JP2021162747A - Image forming apparatus and method for determining life of fixing device - Google Patents

Abstract

To provide an image forming apparatus that can accurately determine the life of a fixing device.SOLUTION: An image forming apparatus 1 comprises: an image forming device 6 that forms a toner image on a sheet P to be conveyed; a fixing device 7 that thermally fixes the toner image to the sheet passing through a pressure area formed between a fixing belt and a pressure roller; a calculation unit 41 that, in a plurality of virtual division areas defined by partitioning the fixing belt into a plurality of pieces in a width direction orthogonal to a conveyance direction of the sheet, calculates a plurality of non-image passage distances indicating the length in the conveyance direction of a portion where toner is not attached in the sheet passing through the pressure area; and a determination unit 42 that, every time the toner image is formed on the sheet, determines the life of the fixing belt based on an integrated passage distance obtained by integrating the non-image passage distances in the respective virtual division areas.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image forming apparatus provided with a fixing device and a method for determining the life of the fixing device.

For example, in the image forming apparatus described in Patent Document 1, the passing time between the pre-fixing paper passage detecting means and the post-fixing paper passing detecting means is calculated, and the cumulative time obtained by accumulating the operating time of the fixing portion is calculated. The remaining life of the anchorage was calculated from the calculated transit time and cumulative time.

Japanese Unexamined Patent Publication No. 2005-257781

In the above-mentioned image forming apparatus, the life of the fixing portion is determined based on the passing time and the cumulative time, but in order to determine the wear of the rollers of the fixing portion, the fixing portion is determined rather than the passing time and the cumulative time. The total distance of passing paper (integrated value of passing distance) is more important. Therefore, with the above-mentioned image forming apparatus, it is difficult to accurately determine the wear of the rollers in the fixing portion.

More specifically, as the paper passes between the roller pairs, the rollers wear due to friction caused by the slight linear velocity difference between the rollers and the paper. Since the molten toner is interposed between the portion of the paper on which the toner image is formed and the roller, the friction is smaller than that in the portion where the toner image is not formed. In the portion of the paper where the toner image is not formed, the roller comes into direct contact with the surface of the paper, so that it is easily worn by friction. That is, in order to accurately determine the life of the fixing portion, it is preferable to determine the life based on how much the portion of the paper on which the toner image is not formed has passed through the fixing portion.

In order to solve the above problems, the present invention provides an image forming device and a method for determining the life of the fixing device, which can accurately determine the life of the fixing device.

The image forming apparatus of the present invention heats the toner image on the image forming apparatus that forms a toner image on a conveyed medium and the medium that passes through a pressurized region formed between a fixing member and a pressing member. In a plurality of virtual division regions set by partitioning the fixing device for fixing and at least one of the fixing member and the pressurizing member in a width direction orthogonal to the transport direction of the medium, the pressurization is performed. A calculation unit that calculates a plurality of non-image passing distances indicating the length in the transport direction of a portion of the medium that passes through the region to which toner is not adhered, and each time the toner image is formed on the medium, respectively. A determination unit for determining the life of at least one of the fixing member and the pressurizing member based on the integrated passing distance obtained by integrating the non-image passing distances in the virtual division region is provided.

In this case, the image forming apparatus includes an optical scanning apparatus that emits scanning light and a photoconductor that carries toner on a portion that receives the scanning light, and the medium has a plurality of the virtual division regions. A plurality of virtual corresponding regions corresponding to the above are set, and the non-image passing distance does not receive scanning light in the region on the photoconductor corresponding to the virtual corresponding region due to the length of the medium in the transport direction. It may be calculated by multiplying the non-exposure rate, which is a ratio, or a value obtained by correcting the non-exposure rate.

In other cases, the image-forming device includes an optical scanning device that emits scanning light and a photoconductor that carries toner on a portion that has not received the scanning light, and the medium includes a plurality of the virtual devices. A plurality of virtual corresponding regions corresponding to the divided regions are set, and the non-image passing distance receives scanning light in the region of the photoconductor corresponding to the virtual corresponding region according to the length of the medium in the transport direction. It may be calculated by multiplying the exposure rate, which is a ratio, or a value obtained by correcting the exposure rate.

In this case, the virtual division region may be set with the width of one pixel formed on the medium.

In other cases, the virtual division region may be set by the width of a plurality of pixels continuous in the width direction formed on the medium.

In this case, the calculation unit may make a correction for increasing the non-image passing distance in the virtual division region corresponding to the end portion in the width direction of the medium among the plurality of virtual division regions.

In this case, the calculation unit may calculate the non-image passing distance corrected based on at least one of the surface roughness of the medium and the thickness of the medium.

In this case, when the toner image is fixed on the other surface of the medium on which the toner image is fixed on one surface, the calculation unit may make a correction for reducing the non-image passing distance.

The method for determining the life of the fixing device of the present invention includes an image forming step of forming a toner image on a conveyed medium and the toner on the medium passing through a pressure region formed between the fixing member and the pressure member. In the fixing step of thermally fixing the image, and in a plurality of virtual division regions set by partitioning at least one of the fixing member and the pressurizing member in a plurality of width directions orthogonal to the transport direction of the medium. A calculation step of calculating a plurality of non-image passing distances indicating the length of a portion of the medium passing through the pressurized region in which toner is not adhered in the transport direction, and each time the toner image is formed on the medium. The present invention includes a determination step of determining the life of at least one of the fixing member and the pressurizing member based on the integrated passing distance obtained by integrating the non-image passing distances in each of the virtual division regions.

In this case, the image forming step includes an exposure step of emitting scanning light toward the photoconductor and a developing step of supporting a toner on a portion of the photoconductor that has received the scanning light, and the medium includes. , A plurality of virtual correspondence areas corresponding to the plurality of virtual division areas are set, and in the calculation step, the non-image passing distance corresponds to the length of the medium in the transport direction and corresponds to the virtual correspondence area. It may be calculated by multiplying the non-exposure rate, which is the ratio of not receiving scanning light in the region on the photoconductor, or the corrected value of the non-exposure rate.

In other cases, the image forming step includes an exposure step of emitting scanning light toward the photoconductor and a developing step of supporting a toner on a portion of the photoconductor that has not received the scanning light. Is set to a plurality of virtual correspondence areas corresponding to the plurality of virtual division areas, and in the calculation step, the non-image passing distance is set to the length of the medium in the transport direction in the virtual correspondence area. It may be calculated by multiplying the exposure rate, which is the ratio of the scanning light received in the corresponding region of the photoconductor, or the corrected value of the exposure rate.

According to the present invention, the life of the fixing device can be accurately determined.

It is a schematic (front view) which shows the image forming apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows typically the fixing apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the image forming apparatus which concerns on one Embodiment of this invention. It is a flowchart of image formation processing which concerns on one Embodiment of this invention. It is a top view which explains the virtual division area and the virtual correspondence area in the fixing device and the like which concerns on one Embodiment of this invention. It is a flowchart of the life determination method of the fixing device which concerns on one Embodiment of this invention. FIG. 5 is a plan view illustrating a virtual division area and a virtual correspondence area in the fixing device or the like according to the third modification of the embodiment of the present invention. It is a flowchart of the life determination method of the fixing device which concerns on 4th modification of one Embodiment of this invention. It is a block diagram which shows the image forming apparatus which concerns on 5th modification of one Embodiment of this invention. It is a flowchart of the life determination method of the fixing device which concerns on 5th modification of one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each figure, "Fr" indicates "front", "Rr" indicates "rear", "L" indicates "left", "R" indicates "right", and "U" indicates "right". "Upper" indicates "upper" and "D" indicates "lower". Further, in the present specification, the direction in which the paper is conveyed is the conveying direction, and the front-rear direction is an example of the width direction orthogonal to the conveying direction. In addition, "upstream" and "downstream" and similar terms refer to "upstream" and "downstream" in the transport direction and similar concepts.

The image forming apparatus 1 according to the embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic view (front view) showing the image forming apparatus 1. FIG. 2 is a cross-sectional view schematically showing the fixing device 7. FIG. 3 is a block diagram showing the image forming apparatus 1.

The image forming apparatus 1 is a printer that forms an image by transferring the toner image G formed by the electrophotographic method onto the paper P. As shown in FIG. 1, the image forming apparatus 1 includes an apparatus main body 2 that constitutes a substantially rectangular parallelepiped appearance. At the lower part of the apparatus main body 2, for example, a paper feed cassette 3 for accommodating paper P (medium) is detachably provided. A paper output tray 4 is provided on the upper surface of the apparatus main body 2. The paper P as an example of the medium is not limited to paper, and may be a resin sheet or the like.

Further, the image forming apparatus 1 includes a paper feeding device 5, an image forming device 6, a fixing device 7, and a control device 8. The paper feed device 5 is provided at the upstream end of the transport path 9A extending from the paper feed cassette 3 to the output tray 4, and feeds the paper P contained in the paper feed cassette 3 one by one to the transport path 9A. The image forming apparatus 6 is provided in the intermediate portion of the conveying path 9A, and forms the toner image G on the conveyed paper P. The fixing device 7 is provided on the downstream side of the transport path 9A, and heat-fixes the toner image G on the paper P. The control device 8 is provided inside the device main body 2 and controls the image forming device 1 in an integrated manner.

The transport path 9A is formed in a substantially S shape when viewed from the front. The transport path 9A is provided with a resist roller pair 10A that temporarily blocks the paper P to be transported and corrects the inclination (skew correction) of the paper P. Below the transport path 9A, a reverse transport path 9B for reversing the paper P and re-transporting it to the image forming apparatus 6 is provided. The reverse transport path 9B branches off on the downstream side of the transport path 9A and extends downward, and the downstream end of the reverse transport path 9B joins the upstream side of the transport path 9A. The reversing transport path 9B is provided with a plurality of transport roller pairs 10B for transporting the paper P.

<Image drawing device>
The image forming apparatus 6 includes a toner container 11, a drum unit 12, and an optical scanning apparatus 13.

(Toner container)
The toner container 11 is arranged in the upper left portion of the apparatus main body 2, and contains, for example, black toner (developer). The toner may be a two-component developer in which a toner and a carrier are mixed, or a one-component developer composed of a magnetic toner.

(Drum unit)
The drum unit 12 includes a photoconductor drum 14, a charging device 15, a developing device 16, and a transfer roller 17. The photoconductor drum 14 is formed in a substantially cylindrical shape that is long in the front-rear direction (width direction), and is rotationally driven around an axis by a motor (not shown). A photosensitive layer (not shown) carrying an electrostatic latent image is formed on the surface layer of the photoconductor drum 14. The charging device 15, the developing device 16, and the transfer roller 17 are arranged around the photoconductor drum 14 in the order of the image forming process. The transfer roller 17 contacts the photoconductor drum 14 from below to form a transfer nip.

(Optical scanning device)
The optical scanning device 13 is provided above the photoconductor drum 14, and emits scanning light toward the surface (photosensitive layer) of the photoconductor drum 14.

<Fixing device>
As shown in FIG. 2, the fixing device 7 includes a fixing belt 20, a pressure roller 21, and a heater 22. The fixing belt 20 and the pressure roller 21 are rotatably supported inside a housing (not shown), and are supported by the device main body 2 via the housing. The heater 22 is provided inside the fixing belt 20.

(Fixing belt)
The fixing belt 20 as an example of the fixing member is an endless belt, and is formed in a substantially cylindrical shape long in the front-rear direction (width direction). The fixing belt 20 has a film 20A having a thickness of about 20 to 100 μm and a release layer 20B laminated on the film 20A. The film 20A is made of a heat-resistant resin (for example, polyimide, polyamide-imide, polyether ether ketone, etc.), and the release layer 20B is a fluororesin (polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, etc.). ) Is formed. The release layer 20B has a function of suppressing adhesion of molten toner. A silicon rubber layer may be provided between the film 20A and the release layer 20B (not shown).

A support member 23 is provided inside the fixing belt 20. The support member 23 is formed of, for example, a metal material in a substantially square cylinder shape that is long in the front-rear direction. The support member 23 penetrates the fixing belt 20 in the front-rear direction and is supported by the housing (see FIG. 5). Caps (not shown) are attached to both front and rear ends of the fixing belt 20, and the fixing belt 20 is rotatably supported by the support member 23 via a pair of caps. Further, the fixing belt 20 is held in a substantially cylindrical shape by a cap. By providing a belt guide (not shown) inside the fixing belt 20 instead of the cap, the substantially cylindrical shape of the fixing belt 20 may be maintained.

(Pressurized roller)
The pressure roller 21 as an example of the pressure member is formed in a substantially cylindrical shape long in the front-rear direction. The pressure roller 21 has an elastic layer 21B laminated on the outer peripheral surface of the core metal 21A and a mold release layer 21C coated on the outer peripheral surface of the elastic layer 21B. For example, the elastic layer 21B is made of silicone rubber, and the release layer 21C is made of a fluororesin. Both ends of the core metal 21A are rotatably supported by a pair of movable frames (not shown). The pressure roller 21 is rotationally driven around an axis by a motor (not shown), and the fixing belt 20 is driven by the pressure roller 21 to rotate.

The movable frame is supported by the housing so as to be swingable in the vertical direction, and is connected to a pressure adjusting unit (not shown) including a spring, an eccentric cam, and the like. When the pressure adjusting unit rotates the movable frame toward the fixing belt 20, the pressure roller 21 is pressed against the fixing belt 20 to form a pressurized region N between the movable frame and the fixing belt 20. On the other hand, when the pressure adjusting unit rotates the movable frame in the direction away from the fixing belt 20, the pressure roller 21 is released from being pressed against the fixing belt 20 to form a pressure-reduced pressure region N. The pressurizing region N refers to a region from the position on the upstream side where the pressure is 0 Pa to the position on the downstream side where the pressure becomes 0 Pa again via the position where the maximum pressure is reached.

(heater)
The heater 22 is formed in a substantially rectangular plate shape that is long in the front-rear direction, and is fixed to the lower surface of the support member 23 via the holding member 24. The holding member 24 is formed of, for example, a heat-resistant resin material in a substantially semi-cylindrical shape that is long in the axial direction, and is arranged along the lower inner surface of the fixing belt 20. The heater 22 has a heat generating resistor (not shown) laminated on the substrate. The heater 22 is held on the lower surface of the holding member 24 in a posture in which the heat generating resistor is directed toward the pressure roller 21, and the heat generating resistor is brought into contact with the inner surface of the fixing belt 20. The heater 22 is in contact with the inner peripheral surface of the fixing belt 20 at a position corresponding to the pressurizing region N. The heat generation resistor generates heat when energized and heats the fixing belt 20.

<Control device>
As shown in FIG. 3, the control device 8 includes an arithmetic processing unit 30, a storage unit 31, and an interface unit 32.

The arithmetic processing unit 30 is a processor that executes arithmetic processing according to a program stored in the storage unit 31. The storage unit 31 includes an auxiliary storage device such as a RAM (Random Access Memory), a ROM (Read Only Memory), and a semiconductor drive. The storage unit 31 stores (stores) programs and data used in the image forming apparatus 1. Controlled devices such as a paper feeding device 5, an image drawing device 6, and a fixing device 7 are electrically connected to the interface unit 32. Further, an external terminal such as a personal computer is connected to the interface unit 32 via a network or the like (not shown). The arithmetic processing unit 30, the storage unit 31, and the interface unit 32 are electrically connected to each other.

The control device 8 and the device to be controlled are connected to a power source via various drive circuits (not shown). Further, the image forming apparatus 1 is provided with an operation panel 33 on which a user operates and information is displayed, and a speaker 34 that emits sound. The operation panel 33 and the speaker 34 are also electrically connected to the interface unit 32 and controlled by the control device 8.

[Image formation process]
Here, the operation of the image forming apparatus 1 will be described with reference to FIGS. 1, 2 and 4. FIG. 4 is a flowchart of the image forming process. For example, the control device 8 executes the image forming process as follows based on the image data input from the external terminal.

First, the control device 8 executes the image forming step S1 for forming the toner image G on the conveyed paper P. The image forming step S1 is an image forming process in the electrophotographic method, and includes a charging step S11, an exposure step S12, a developing step S13, and a transfer step S14 (see FIG. 4).

Specifically, the charging device 15 charges the surface (photosensitive layer) of the photoconductor drum 14 (for example, gives a negative charge (charging step S11)). The optical scanning device 13 emits scanning light based on the image data input to the photoconductor drum 14 (exposure step S12). The photoconductor drum 14 receives scanning light and carries an electrostatic latent image. Specifically, the negative charge disappears in the portion of the photosensitive layer of the photoconductor drum 14 that receives the scanning light, and an electrostatic latent image (negative latent image) drawn by the negative charge is formed on the photoconductor drum 14. Will be done.

Subsequently, the developing apparatus 16 develops the toner image G on the photoconductor drum 14 using the toner supplied from the toner container 11 (development step S13). Specifically, the negatively charged toner repels the portion that has not received the scanning light and adheres to the portion that has received the scanning light. Therefore, the photoconductor drum 14 carries the toner (toner image G) on the portion that has received the scanning light.

The paper feed device 5 separates the paper P in the paper feed cassette 3 one by one and sends it out to the transport path 9A. The paper P is conveyed along the transfer path 9A, skew-corrected by the resist roller pair 10A, and enters the transfer nip. The transfer roller 17 transfers the toner image G on the photoconductor drum 14 to the surface of the paper P passing through the transfer nip (transfer step S14).

Next, the control device 8 executes the fixing step S2 (see FIG. 4). In the fixing step S2, the fixing device 7 heat-fixes the toner (toner image G) on the paper P passing through the pressure region N formed between the fixing belt 20 and the pressure roller 21. Specifically, the paper P on which the toner image G is transferred enters the pressurizing region N of the fixing device 7, and the fixing belt 20 heated by the heater 22 passes through the pressurizing region N while rotating around the axis. The toner (toner image G) on the paper P is heated. The pressurizing roller 21 pressurizes the toner on the paper P passing through the pressurizing region N while rotating around the axis. The paper P on which the toner image G is fixed on one surface is discharged to the paper ejection tray 4.

When printing (image formation) is performed on both sides of the paper P, the paper P that has passed through the fixing device 7 is switched back at the downstream end of the transport path 9A and sent to the reverse transport path 9B. The paper P is conveyed by the transfer roller pair 10B, returned from the reverse transfer path 9B to the transfer path 9A, skew-corrected by the resist roller pair 10A, and then sent to the transfer nip. Then, the image forming step S1 and the fixing step S2 are executed again, and the double-sided printed paper P is discharged to the paper ejection tray 4.

[Determination of life of conventional fixing device]
By the way, when the paper P passes through the pressure region N, the release layer 20B of the fixing belt 20 is worn due to the friction caused by the slight difference in linear velocity between the fixing belt 20 and the paper P. For example, as the release layer 20B wears, the molten toner adheres to the fixing belt 20, and the adhered toner (offset toner) reattaches to the paper P to be conveyed later, so-called offset occurs. Further, for example, the offset toner may adhere to the pressure roller 21 and may adhere to the back surface of the paper P which is later conveyed. Conventionally, it has been determined that the fixing belt 20 or the pressure roller 21 has reached the end of its life when an offset image is output or when a transfer defect (jam) occurs due to the adhesive force between the offset toner and the paper P. .. When such a problem occurred, the image forming apparatus 1 was stopped, and the fixing belt 20, the pressure roller 21, or the entire fixing device 7 was replaced. Therefore, conventionally, the fixing device 7 and the like cannot be replaced until the end of the service life, and it is not possible to prevent the occurrence of defects such as offset images and jams. Further, since the image forming apparatus 1 cannot be used until the replacement of the fixing apparatus 7 and the like is completed, the productivity for the user is lowered.

[Fixing belt wear]
Here, the wear of the fixing belt 20 will be described in detail. Since the molten toner is interposed between the portion of the paper P on which the toner image G is formed and the fixing belt 20, the friction between the two is smaller than that in the portion where the toner image G is not formed. .. On the other hand, in the portion of the paper P where the toner image G is not formed, the fixing belt 20 is in direct contact with the surface of the paper P and is easily worn by friction. Therefore, in the image forming apparatus 1 according to the first embodiment, in order to accurately determine the life of the fixing apparatus 7, how much the portion of the paper P on which the toner image G is not formed forms the pressure region N. It is provided with a lifespan determination unit 40 that determines the lifespan based on whether or not the material has passed.

[Life judgment unit]
The life determination unit 40 for determining the life of the fixing device 7 will be described with reference to FIGS. 3 and 5. FIG. 5 is a plan view illustrating the virtual division area A1 and the virtual correspondence area A2.

As shown in FIG. 3, the life determination unit 40 is provided as a function of the control device 8. The life determination unit 40 includes a calculation unit 41, a determination unit 42, and a notification unit 43.

<Calculation unit>
The calculation unit 41 is realized by the arithmetic processing unit 30 and a program (including data stored in the storage unit 31) executed by the calculation processing unit 30. The calculation unit 41 sets a plurality of non-image passing distances (D) indicating the length in the transport direction of the portion of the paper P passing through the pressurized region N in the plurality of virtual division regions A1 in the transport direction. calculate.

The virtual division area A1 will be described. As shown by the alternate long and short dash line in FIG. 5, a plurality of virtual division areas A1 divided into a plurality of sections (divided) in the front-rear direction (width direction) are set in the fixing belt 20. To be precise, the fixing belt 20 (pressurizing roller 21) is set with a maximum width W that allows the pressure region N to pass through, and a plurality of the maximum width W can be divided in the front-rear direction. Virtual division area A1 is set. The virtual division area A1 is coordinate information set by virtually dividing the fixing belt 20 in the width direction, and is set by, for example, the width of one pixel formed on the paper P. The virtual division area A1 is stored in the storage unit 31. The virtual division area A1 shown in FIG. 5 is schematically shown, and does not indicate an accurate width of one pixel.

(Calculation method of non-image passing distance)
Next, a method for calculating the non-image passing distance (D) will be specifically described. As shown by the alternate long and short dash line in FIG. 5, a plurality of virtual correspondence areas A2 corresponding to the plurality of virtual division areas A1 are set on the paper P. The virtual division area A1 is coordinate information set by virtually dividing the paper P in the width direction, and is stored in the storage unit 31. The non-image passing distance (D) is the non-exposure rate (NE), which is the ratio of the length L of the paper P in the transport direction to the region on the photoconductor drum 14 corresponding to the virtual correspondence region A2, which is not received by scanning light. It is a value calculated by multiplying. The calculation unit 41 stores the calculated non-image passing distance (D) in the storage unit 31.

The paper cassette 3 is provided with a paper detection unit 35 (see FIG. 3) for reading the size of the paper P (length L in the transport direction and width in the front-rear direction). For example, the paper detection unit 35 is electrically connected to the interface unit 32 (FIG. 3). (See). The size of the paper P detected by the paper detection unit 35 is stored in the storage unit 31, and the calculation unit 41 grasps the size of the paper P by referring to the storage unit 31. The installation is not limited to the paper feed cassette 3, and may be installed at a position facing the transport path 9A. In this case, the paper detection unit 35 reads the size of the paper P transported through the transport path 9A. In the case of paper P having a large size, the user may input the size of paper P from the operation panel 33.

Further, since margins are generally provided at both ends of the paper P in the transport direction, the calculation unit 41 describes the non-image passing distance (D) including the margins at both ends of the paper P in the transport direction. Is calculated. For example, the calculation unit 41 reads the margin information from the image data and adds it to the non-image passing distance (D).

Further, the non-image passing distance (D) is a value obtained by simply multiplying the length L of the paper P in the transport direction and the non-exposure rate (NE), but the present invention is not limited to this. For example, the non-image passing distance (D) may be calculated by multiplying the length L of the paper P in the transport direction by a value (NE') corrected for the non-exposure rate (NE). The value obtained by multiplying the length L of the paper P in the transport direction and the corrected value (NE') of the non-exposure rate (NE) is simply the product of the length L and the non-exposure rate (NE). It is preferable that the value (NE') corrected for the non-exposure rate (NE) is set so that the value is smaller than the value.

<Judgment unit>
As shown in FIG. 3, the determination unit 42 is realized by the arithmetic processing unit 30 and the program (including the data stored in the storage unit 31) executed by the arithmetic processing unit 30. Each time the toner image G is formed on the paper P (for each image formation or for each paper P), the determination unit 42 calculates an integrated passing distance (AD) obtained by integrating the non-image passing distances (D) in each virtual division region A1. calculate. The determination unit 42 stores the calculated integrated passing distance (AD) in the storage unit 31.

The determination unit 42 determines the life of the fixing belt 20 based on the integrated passing distance (AD) each time a toner image G is formed on the paper P (each image formation). Specifically, the storage unit 31 stores a threshold value (T) of an integrated passing distance (AD) indicating the life of the fixing belt 20. The threshold value (T) is, for example, a value determined based on an experiment or the like. The threshold value (T) is not limited to a value indicating that the life of the fixing belt 20 has completely expired, and is preferably a value indicating that the life of the fixing belt 20 will soon be reached. The determination unit 42 determines that the fixing belt 20 will soon reach the end of its life when any one of the plurality of integrated passage distances (AD) corresponding to the plurality of virtual division regions A1 exceeds the threshold value (T).

<Notification unit>
The notification unit 43 is realized by the arithmetic processing unit 30 and a program (including data stored in the storage unit 31) executed by the arithmetic processing unit 30. The notification unit 43 notifies the user of the determination result by the determination unit 42. Specifically, when the determination unit 42 determines that the fixing belt 20 has reached the end of its life, the determination unit 42 controls to display information prompting the replacement of the fixing device 7 on the operation panel 33, a warning sound from the speaker 34, or the like. Controls to output sound.

[Method for determining the life of the fixing device]
Next, a method of determining the life of the fixing device 7 will be described with reference to FIG. FIG. 6 is a flowchart of a method for determining the life of the fixing device 7.

As described above, the control device 8 executes the image forming process (image forming step S1, fixing step S2). Further, the control device 8 executes the life determination process of the fixing device 7 (fixing belt 20) in parallel with the image forming process after the exposure step S12.

First, the calculation unit 41 of the control device 8 calculates the non-image passing distance (D) by taking the product of the length L of the paper P in the transport direction and the non-exposure rate (NE) in each virtual division region A1. (Calculation step S3). The calculation unit 41 repeatedly executes the calculation step S3 until the non-image passing distance (D) is calculated for all the virtual division regions A1 (NO in S31).

After calculating the non-image passing distance (D) for all the virtual division regions A1 (YES in S31), the determination unit 42 of the control device 8 executes the integration determination step S4. The integration determination step S4 includes an integration step S41 that integrates the non-image passing distance (D) for each virtual division region A1 to calculate the integrated passing distance (AD), and the integrated passing distance (AD) and the threshold value (T). A determination step S42 for comparing the above.

When the integrated passing distance (AD) is equal to or less than the threshold value (T) (NO in S42), the determination unit 42 determines whether or not the integrated passing distance (AD) has been determined for all the virtual division regions A1 (S43). ). The determination unit 42 repeatedly executes the integration step S41 until the integration passage distance (AD) is determined for all the virtual division regions A1 (NO in S43). When the integrated passing distance (AD) is equal to or less than the threshold value (T) and the integrated passing distance (AD) is determined for all the virtual division regions A1 (YES in S43), the determination unit 42 does nothing and performs the life determination process. To finish.

On the other hand, when at least one integrated passing distance (AD) exceeds the threshold value (T) (YES in S42), the notification unit 43 of the control device 8 waits for the end of the image formation process and presses the operation panel 33 and the speaker 34. It controls and notifies the user that it is time to replace the fixing device 7 (notification step S5).

After that, the user contacts the exchange service provider, and the exchange service provider replaces the entire fixing device 7. The entire fixing device 7 may be replaced, but only the fixing belt 20 may be replaced.

In the life determination method of the fixing device 7 according to the present embodiment, the integration step S41 is included in the integration determination step S4, but the integration step S41 may be included in the calculation step S3. That is, instead of the determination unit 42 calculating the integrated passage distance (AD), the calculation unit 41 may calculate the integrated passage distance (AD).

In the image forming apparatus 1 (method for determining the life of the fixing apparatus 7) according to the present embodiment described above, the non-image passing distance (D) of the paper P passing through the pressurized region N is calculated, and the non-image passing distance (D) is calculated. The life of the fixing belt 20 and the pressure roller 21 was determined by the integrated value of D). According to this configuration, the life of the fixing device 7 (fixing belt 20) is accurately determined based on how much the portion of the paper P on which the toner image G is not formed has passed through the pressure region N. can do. As a result, since the fixing device 7 can be replaced before the fixing device 7 reaches the end of its life, it is possible to prevent the occurrence of defects such as offset images and jams, and the productivity associated with the replacement of the fixing device 7 can be prevented. Can be prevented from decreasing.

Further, according to the image forming apparatus 1 according to the present embodiment, the ratio of the toner not adhering to the virtual corresponding region A2 of the paper P can be obtained by the non-exposure rate (NE). As a result, the non-image passing distance (D) can be easily calculated by taking the product of the length L of the paper P in the transport direction and the non-exposure rate (NE).

Further, according to the image forming apparatus 1 according to the present embodiment, since the virtual division region A1 has a width of one pixel (distance in the width direction), the life of the fixing belt 20 can be determined in detail.

By the way, the paper P is generally provided with margins at both ends in the width direction and both ends in the transport direction, and the non-image passing distance (D) (D) corresponding to both ends in the width direction of the paper P. It is also conceivable to calculate only (= the integrated value of the lengths of the paper P in the transport direction) to determine the life of the fixing belt 20. However, since the contact positions between both ends of the paper P in the width direction and the fixing belt 20 differ depending on the size of the paper P, only the non-image passing distance (D) corresponding to both ends of the paper P in the width direction is calculated. It is not possible to make an accurate life judgment by itself. Therefore, in order to accurately determine the life, the image forming apparatus 1 according to the present embodiment is divided into a plurality of virtual division areas A1, and the non-image passage distance (D) is set for each virtual division area A1. It becomes important to ask.

[Modification example]
Hereinafter, various modifications of the image forming apparatus 1 (method for determining the life of the fixing apparatus 7) according to the present embodiment will be described. Hereinafter, the same or corresponding configurations as those of the image forming apparatus 1 (method for determining the life of the fixing apparatus 7) already described will be designated by the same reference numerals, and the description thereof will be omitted.

<First modification>
In the image forming apparatus 1 (method for determining the life of the fixing device 7) described above, the life determining unit 40 determines the life of the fixing belt 20, but the present invention is not limited to this. In the image forming apparatus 1 according to the first modification, the life determination unit 40 may determine the life of the pressure roller 21 or may determine the life of both the fixing belt 20 and the pressure roller 21. That is, a plurality of virtual division regions A1 may be set on the pressurizing roller 21, and the calculation unit 41 may calculate a plurality of non-image passage distances (D) in these virtual division regions A1.

According to the image forming apparatus 1 (method for determining the life of the fixing device 7) according to the first modification described above, the life of the fixing belt 20 and the pressure roller 21 can be accurately determined. The entire fixing device 7 may be replaced, but only the parts (fixing belt 20 or pressure roller 21) determined to reach the end of their service life may be replaced.

<Second modification>
In the image forming apparatus 1 (method for determining the life of the fixing apparatus 7) described above, the toner (toner image G) is carried on the portion where the photoconductor drum 14 receives the scanning light, but the present invention is not limited to this. In the image forming apparatus 1 according to the second modification, on the contrary, the photoconductor drum 14 carries toner on a portion that has not received scanning light. In this case, the portion of the photosensitive layer of the negatively charged photoconductor drum 14 that receives the scanning light loses its charge, and an electrostatic latent image (positive latent image) drawn by the negative charge is displayed on the photoconductor drum 14. It is formed. In the developing step S13, the positively charged toner repels the portion that has received the scanning light and adheres to the portion that has not received the scanning light. As a result, the toner image G is formed on the portion of the photoconductor drum 14 that has not received the scanning light.

Further, in the calculation step S3 of the life determination method of the fixing device 7 according to the second modification, the non-image passing distance (D) is the length L of the paper P in the transport direction and the photoconductor corresponding to the virtual corresponding region A2. It is calculated by multiplying the exposure rate (E), which is the ratio of the scanning light received in the region of the drum 14, or the corrected value (E') of the exposure rate (E). The value obtained by multiplying the length L of the paper P in the transport direction and the corrected value (E') of the exposure rate (E) is simply the product of the length L and the exposure rate (E). It is preferable that the value (E') corrected for the exposure rate (E) is set so that the value is smaller than the value.

According to the image forming apparatus 1 (method for determining the life of the fixing device 7) according to the second modification described above, the life of the fixing device 7 can be accurately determined, and the image forming according to the above-described embodiment is performed. The same effect as that of the device 1 can be obtained.

<Third modification example>
In the image forming apparatus 1 (method for determining the life of the fixing apparatus 7) described above, the virtual division region A1 is set by the width of one pixel formed on the paper P, but the present invention is not limited to this. As shown in FIG. 7, in the image forming apparatus 1 according to the third modification, the virtual division region A3 is set by the width of a plurality of pixels continuous in the width direction formed on the paper P. That is, the virtual division area A3 and the corresponding virtual correspondence area A4 are set in a strip shape extending in the transport direction. The number of settings (number of divisions) of the virtual division area A3 may be two or more. Further, the method of calculating the non-image passing distance (D) is the same as the method already described. That is, the non-image passing distance (D) is the non-exposure rate (NE) which is the ratio of the length L of the paper P in the transport direction to the region on the photoconductor drum 14 corresponding to the virtual correspondence region A4 so as not to receive the scanning light. ) Etc. are multiplied.

According to the image forming apparatus 1 (method for determining the life of the fixing apparatus 7) according to the third modification described above, since the virtual division region A3 has a width of a plurality of pixels continuous in the width direction, the width of one pixel is used. Compared with the case where the non-image passing distance (D) is calculated using the set virtual division area A1, the amount of calculation required for calculating the non-image passing distance (D) can be reduced. As a result, the calculation of the non-image passing distance (D) can be speeded up.

<Fourth modification>
In the image forming apparatus 1 (life determination method of the fixing apparatus 7) described above, the non-image passing distance (D) was calculated by the same calculation method in all the virtual division regions A1. However, the release layer 20B of the fixing belt 20 (the release layer 21C of the pressure roller 21) is likely to be worn at the portion of the paper P that comes into contact with the end (edge) in the front-rear direction (width direction). Therefore, in the image forming apparatus 1 according to the fourth modification, the calculation unit 41 performs the non-image passing distance (D) in the virtual division area A1 corresponding to the front-rear end of the paper P among the plurality of virtual division areas A1. ) Is increased. The correction amount is experimentally obtained and stored in the storage unit 31 in advance.

As shown in FIG. 8, in the calculation step S3, it is determined whether or not the virtual division area A1 corresponds to the edge of the paper P (step S6). When the virtual division area A1 does not correspond to the edge of the paper P (NO in S6), the non-image passing distance (D) (without correction) is calculated (step S61). On the other hand, when the virtual division area A1 corresponds to the edge of the paper P (YES in S6), the non-image passing distance (D) is calculated, and the calculated non-image passing distance (D) is positively corrected (step S62). .. After that, after calculating the non-image passing distance (D) for all the virtual division regions A1, the integration determination step S4 and the like are executed.

According to the image forming apparatus 1 (method for determining the life of the fixing device 7) according to the third modification described above, the fixing belt is considered to be easily worn by the release layers 20B and 21C at the edge of the paper P. The life of 20 etc. can be determined. Thereby, the life of the fixing device 7 can be determined more accurately.

<Fifth modification>
In the image forming apparatus 1 (method for determining the life of the fixing apparatus 7) according to the fifth modification, the calculation unit 41 calculates the non-image passing distance (D) corrected based on the surface roughness of the paper P and the thickness of the paper P. calculate.

The surface roughness and thickness of the paper P are detected by an optical sensor 45 provided on the paper feed cassette 3. As shown in FIG. 9, the optical sensor 45 is electrically connected to the interface unit 32 and transmits a detection signal to the control device 8. The optical sensor 45 includes a light emitting unit that irradiates light toward the paper P, a first light receiving unit that receives the light reflected on the surface of the paper P, and a second light receiving unit that receives the light transmitted through the paper P. have. The surface roughness of the paper P is detected by the amount of light received by the first light receiving unit, and the thickness of the paper P is detected by the amount of light received by the second light receiving unit.

As the surface roughness of the paper P becomes rougher, the release layers 20B and 21C tend to wear. Therefore, when the surface roughness of the paper P becomes rough, the calculation unit 41 makes a correction to increase the non-image passing distance (D). conduct. Further, since the release layers 20B and 21C tend to wear as the thickness of the paper P increases, the calculation unit 41 makes a correction to increase the non-image passing distance (D) when the thickness of the paper P becomes thick. conduct. On the other hand, when the surface roughness of the paper P is low (smooth) or the paper P is thin, the calculation unit 41 makes a correction to reduce the non-image passing distance (D).

The median surface roughness and thickness of the paper P are arbitrarily set according to the specifications of the image forming apparatus 1, and are stored in the storage unit 31 in advance. The control device 8 determines whether the surface roughness of the paper P is rough or smooth based on the median value. Further, the control device 8 determines the thickness of the paper P as well as the surface roughness of the paper P. Further, the storage unit 31 stores a control table showing the correspondence between the surface roughness and thickness of the paper P and the correction amount. The calculation unit 41 refers to the control table and changes the correction amount according to the surface roughness and thickness of the paper P. The amount of correction may be obtained experimentally.

As shown in FIG. 10, before executing the calculation step S3, the control device 8 receives the detection result from the optical sensor 45, determines the surface roughness and the thickness of the paper P, and responds to the determination result. The correction amount is selected (paper quality determination step S7). Next, in the calculation step S3, the non-image passing distance (D) corrected by the correction amount selected in the paper quality determination step S7 is calculated. After that, after calculating the non-image passing distance (D) for all the virtual division regions A1, the integration determination step S4 and the like are executed.

According to the image forming apparatus 1 (method for determining the life of the fixing apparatus 7) according to the fifth modification described above, as the surface roughness and thickness of the paper P increase, the release layers 20B and 21C are likely to be worn. In consideration of this, the life of the fixing belt 20 and the like can be determined. Thereby, the life of the fixing device 7 can be determined more accurately. The surface roughness and thickness of the paper P are not limited to the configuration read by the optical sensor 45, and the user may input the surface roughness and thickness of the paper P from the operation panel 33, for example. Further, in the above description, the calculation unit 41 calculates the corrected non-image passing distance (D) based on both the surface roughness of the paper P and the thickness of the paper P, but the present invention is not limited to this. The corrected non-image passing distance (D) may be calculated based on at least one of the surface roughness of P and the thickness of the paper P.

<6th modification>
By the way, when the paper P passes through the pressure region N, it is presumed that calcium carbonate or the like on the surface of the paper P is peeled off or embedded. Therefore, when double-sided printing is performed, the paper P on which the toner image G is fixed on one side, in other words, the paper P that has passed through the pressure region N, has a rougher surface than the paper P before passing through the pressure region N. It is presumed that the paper is smoothed and becomes very slightly thin. Therefore, in the image forming apparatus 1 (method for determining the life of the fixing device 7) according to the sixth modification, when the toner image G is fixed on the other surface of the paper P on which the toner image G is fixed on one surface, the calculation unit 41 determines. A correction is performed to reduce the non-image passing distance (D). That is, when performing double-sided printing, the calculation unit 41 negatively corrects the non-image passing distance (D). The correction amount is experimentally obtained and stored in the storage unit 31 in advance.

According to the image forming apparatus 1 (method for determining the life of the fixing device 7) according to the sixth modification described above, the life of the fixing belt 20 is extended in consideration of the fact that the surface of the paper P is smoothed during double-sided printing. It can be determined. Thereby, the life of the fixing device 7 can be determined more accurately.

The features of the inventions according to the first to sixth modifications may be combined with each other as long as there is no contradiction.

In the image forming apparatus 1 according to the present embodiment (including the first to sixth modifications; the same applies hereinafter), the calculation unit 41 has a length L of the paper P and a non-exposure rate (NE) (exposure rate (exposure rate (exposure rate)). The product with E)) was defined as the non-image passing distance (D), but the present invention is not limited to this. For example, the calculation unit 41 may calculate the non-image passage distance (D) in the virtual correspondence areas A2 and A4 (virtual division areas A1 and A3) based on the image data transmitted from the external terminal. Further, an image sensor (not shown) for photographing the toner image G transferred to the paper P is provided, and the non-image passing distance in the virtual corresponding areas A2 and A4 (virtual division areas A1 and A3) from the image captured by the image sensor. (D) may be calculated.

Further, in the image forming apparatus 1 according to the present embodiment, the fixing belt 20 is adopted as an example of the fixing member, but the fixing belt 20 is not limited to this, and as another example of the fixing member, a roller such as a pressure roller 21 is used. May be (not shown). Further, although the pressure roller 21 has been adopted as an example of the pressure member, the pressure roller 21 is not limited to this, and a belt such as the fixing belt 20 may be used as another example of the pressure member (not shown). .. Further, although the pressure roller 21 was rotationally driven, the fixing belt 20 may be rotationally driven instead. Further, the pressure adjusting unit moves the pressure roller 21 to change the pressure in the pressure region N, but the pressure is not limited to this, and the fixing belt 20 is moved to change the pressure in the pressure region N. It may be configured. Further, the heater 22 has a configuration having a heat generating resistor in contact with the inner peripheral surface of the fixing belt 20, but the present invention is not limited to this, and for example, a halogen heater or an induction heating type heater may be used (not shown). ).

Further, the image forming apparatus 1 according to the present embodiment is a monochrome printer, but the present invention is not limited to this, and the present invention may be applied to, for example, a color printer, a copying machine, a facsimile, a multifunction device, or the like. When the image forming apparatus forms a color image, the integrated non-exposure rate (integrated exposure rate) obtained by superimposing (totaling) the non-exposure rates (NE) (exposure rate (E)) of a plurality of colors is obtained. The non-image passing distance (D) is calculated using this integrated non-exposure rate and the like.

The description of the above-described embodiment shows one aspect of the method for determining the life of the image forming apparatus and the fixing apparatus according to the present invention, and the technical scope of the present invention is not limited to the above-described embodiment. .. The present invention may be variously modified, replaced or modified without departing from the spirit of the technical idea, and the claims include all embodiments that may be included within the scope of the technical idea.

1 Image forming device 6 Image forming device 7 Fixing device 13 Optical scanning device 14 Photoreceptor drum (photoreceptor)
20 Fixing belt (fixing member)
21 Pressurizing roller (pressurizing member)
41 Calculation unit 42 Judgment unit A1, A2 Virtual division area A2, A4 Virtual correspondence area G Toner image N Pressurized area S1 Image drawing process S2 Fixing process S3 Calculation process S12 Exposure process S13 Development process S42 Judgment process

Claims (11)

An image-forming device that forms a toner image on the conveyed medium,
A fixing device for thermally fixing the toner image to the medium passing through a pressure region formed between the fixing member and the pressure member.
The medium passing through the pressurizing region in a plurality of virtual division regions set by partitioning at least one of the fixing member and the pressurizing member in a plurality of width directions orthogonal to the transport direction of the medium. A calculation unit that calculates a plurality of non-image passing distances indicating the length of the portion to which toner is not attached in the transport direction, and
Each time the toner image is formed on the medium, the life of at least one of the fixing member and the pressurizing member is determined based on the integrated passing distance obtained by integrating the non-image passing distances in each virtual division region. An image forming apparatus including a determination unit for performing an image. The image forming device is
An optical scanning device that emits scanning light,
It has a photoconductor that supports toner on the portion that has received the scanning light, and has
A plurality of virtual correspondence areas corresponding to the plurality of virtual division areas are set in the medium.
The non-image passing distance is obtained by correcting the non-exposure rate or the non-exposure rate, which is the ratio of not receiving scanning light in the region on the photoconductor corresponding to the virtual corresponding region, to the length in the transport direction of the medium. The image forming apparatus according to claim 1, wherein the image forming apparatus is calculated by multiplying the values. The image forming device is
An optical scanning device that emits scanning light,
It has a photoconductor that supports toner on a portion that has not received the scanning light.
A plurality of virtual correspondence areas corresponding to the plurality of virtual division areas are set in the medium.
The non-image passing distance is obtained by multiplying the length of the medium in the transport direction by the exposure rate, which is the ratio of the scanning light received in the area of the photoconductor corresponding to the virtual corresponding area, or a value obtained by correcting the exposure rate. The image forming apparatus according to claim 1, wherein the image forming apparatus is calculated by combining the images. The image forming apparatus according to any one of claims 1 to 3, wherein the virtual division region is set with a width of one pixel formed on the medium. The image forming apparatus according to any one of claims 1 to 3, wherein the virtual division region is set by the width of a plurality of pixels continuous in the width direction formed on the medium. The calculation unit is characterized in that, among the plurality of virtual division regions, a correction for increasing the non-image passing distance is performed in the virtual division region corresponding to the end portion in the width direction of the medium. The image forming apparatus according to any one of 5. The calculation unit according to any one of claims 1 to 6, wherein the calculation unit calculates the non-image passing distance corrected based on at least one of the surface roughness of the medium and the thickness of the medium. Image forming device. 7. The image forming apparatus according to item 1. An image forming process that forms a toner image on the conveyed medium,
A fixing step of thermally fixing the toner image to the medium passing through a pressure region formed between the fixing member and the pressure member.
The medium passing through the pressurizing region in a plurality of virtual division regions set by partitioning at least one of the fixing member and the pressurizing member in a plurality of width directions orthogonal to the transport direction of the medium. A calculation process for calculating a plurality of non-image passing distances indicating the length of the portion to which the toner is not adhered in the transport direction, and
Each time the toner image is formed on the medium, the life of at least one of the fixing member and the pressurizing member is determined based on the integrated passing distance obtained by integrating the non-image passing distances in each virtual division region. A method for determining the life of a fixing device, which comprises a determination step for performing. The image forming process is
An exposure process that emits scanning light toward the photoconductor,
Including a developing step of supporting toner on a portion of the photoconductor that has received the scanning light.
A plurality of virtual correspondence areas corresponding to the plurality of virtual division areas are set in the medium.
In the calculation step, the non-exposure rate or the non-exposure rate, which is the ratio of the non-image passing distance to the length in the transport direction of the medium, in the region on the photoconductor corresponding to the virtual correspondence region, is not received by scanning light. The method for determining the life of a fixing device according to claim 9, wherein the calculation is performed by multiplying the values obtained by correcting the exposure rate. The image forming process is
An exposure process that emits scanning light toward the photoconductor,
A development step of supporting a toner on a portion of the photoconductor that has not received the scanning light is included.
A plurality of virtual correspondence areas corresponding to the plurality of virtual division areas are set in the medium.
In the calculation step, the exposure rate or the exposure rate, which is the ratio of the non-image passing distance to the length in the transport direction of the medium, in which the scanning light is received in the region of the photoconductor corresponding to the virtual correspondence region. The method for determining the life of a fixing device according to claim 9, wherein the calculation is performed by multiplying the corrected values.

Images