Image forming apparatus and printing system

Abstract

To provide an image formation apparatus capable of predicting a failure before a polygon mirror motor completely malfunctions.SOLUTION: An image formation apparatus according to an embodiment is the image formation apparatus which uses a polygon mirror rotated by a polygon mirror motor to scan laser light onto a photoreceptor to form an image, and includes: first determination means; second determination means; and storage means. The first determination means, after the polygon mirror motor has been activated and transitions to steady rotation within the target rotation speed range, performs repetition at periodic intervals and determines whether or not the rotation speed of the polygon mirror motor is within the target rotation speed range. The second determination means determines a failure of the polygon mirror motor when the rotation speed is outside the target rotation speed range in the prescribed number of consecutive times. The storage means stores the number of times when the rotation speed returns from outside the target rotation speed range to within the target rotation speed range less than the prescribed number of consecutive times.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an image forming apparatus. and printing systems Regarding. [Background technology]

[0002] Image forming devices installed in workplaces include printers that form visible images corresponding to image data on paper. In addition to these printers, digital multifunction peripherals (MFPs) are also widely used. These printers include scanners that capture text, illustrations, or photographs on a target object as light intensity and generate image data corresponding to the light intensity. Electrophotographic printers are widely used as printers for image forming devices. These electrophotographic printers include an exposure unit that includes multiple laser light sources and an optical system such as a polygon mirror. The exposure unit forms a latent image on a photoreceptor drum 30 by irradiating the photoreceptor drum with laser light controlled according to image data. The image forming device visualizes this latent image with a developing agent to obtain a visible image. The image forming device first transfers the visible image to a transfer belt and then transfers the transferred visible image to paper. The image forming device then fixes (fixes) the transferred visible image to the paper using a fixing unit.

[0003] The polygon mirror motor that rotates the polygon mirror of the exposure unit is supplied with an external power supply, an ON signal, an internal or external clock signal for controlling the rotation speed, etc. When the ON signal is input, the polygon mirror motor starts to rotate and the rotation speed increases. When the rotation speed corresponding to the clock is reached, the polygon mirror motor enters steady rotation and outputs a rotation synchronization signal.

[0004] Conventionally, to detect an abnormality in a polygon mirror motor, an image forming apparatus periodically detects the rotation synchronization signal output from the motor after the polygon mirror motor reaches a steady rotation. If the synchronization signal is not obtained, the image forming apparatus determines that there is an abnormality in the motor, displays the abnormality on the display unit of the operation panel equipped with the image forming apparatus, and stops operation of the image forming apparatus. The image forming apparatus cannot be used until repairs such as replacement of the polygon mirror motor are completed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6980465 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the embodiments of the present invention is to provide an image forming apparatus capable of predicting a failure of a polygon mirror motor before the motor completely fails. and printing systems The aim is to provide the following. [Means for solving the problem]

[0007] In one embodiment, the image forming apparatus is an image forming apparatus that forms an image by scanning a laser beam onto a photosensitive member using a polygon mirror rotated by a polygon mirror motor, and includes a first determining means, a second determining means, a storing means, and A third means of judgment; and The first determination means repeatedly determines at regular intervals whether the rotation speed of the polygon mirror motor is within the target rotation speed range after the polygon mirror motor is started and has transitioned to steady rotation within the target rotation speed range. The second determination means When the polygon mirror motor is rotating steadily, When the number of rotations falls outside the target range for a specified number of consecutive times, it is determined that the polygon mirror motor has failed. When the polygon mirror motor is rotating at a steady state, When the rotation speed returns from outside the target rotation speed range to within the target rotation speed range within a specified number of consecutive times, the number of times is stored. The third determining means determines that there is a sign of a malfunction of the polygon mirror motor when the stored number of times reaches a specified number while the polygon mirror motor is rotating steadily. In one embodiment, a printing system includes an image forming apparatus that forms an image by scanning a laser beam onto a photosensitive element using a polygon mirror rotated by a polygon mirror motor, and a server device that communicates with the image forming apparatus via a network. The image forming apparatus includes a first determination means, a second determination means, a storage means, and a communication means. The first determination means, after the polygon mirror motor is started and transitions to steady rotation within a target rotation speed range, repeatedly determines at regular intervals whether the rotation speed of the polygon mirror motor is within the target rotation speed range. The second determination means determines that the polygon mirror motor is faulty when the rotation speed of the polygon mirror motor falls outside the target rotation speed range a predetermined number of consecutive times during steady rotation. The storage means stores the number of times when the polygon mirror motor returns from outside the target rotation speed range to within the target rotation speed range less than the predetermined number of consecutive times during the steady rotation. The communication means transmits the number of times stored by the storage means to the server device via the network. The server device also includes a third determination means. The third determining means determines that when the number of times transmitted from the image forming apparatus reaches a specified number, it is a sign of a malfunction of the polygon mirror motor provided in the image forming apparatus. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a printing system including an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically illustrating an example of the configuration of the image forming apparatus according to the embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of an exposure unit used in the image forming apparatus according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing an example of the configuration of an exposure unit arranged in the image forming apparatus according to the embodiment. [Figure 5] FIG. 5 is a block diagram showing an example of the configuration of a control system in the image forming apparatus according to the embodiment. [Figure 6] FIG. 6 is a block diagram showing an example of the configuration of a nonvolatile memory of a printer in the image forming apparatus according to the embodiment. [Figure 7] FIG. 7 is a diagram showing the first part of a series of flowcharts for explaining an example of the operation of diagnosing the polygon mirror motor in the image forming apparatus according to the embodiment. [Figure 8] FIG. 8 is a diagram showing the second part of a series of flowcharts for explaining an example of the operation of diagnosing the polygon mirror motor. [Figure 9] FIG. 9 is a time chart showing the relationship between the motor rotation speed, the rotation synchronization signal, and the synchronization detection control when the polygon mirror motor in the image forming apparatus according to the embodiment is normal. [Figure 10] FIG. 10 is a time chart showing the relationship between the motor rotation speed, rotation synchronization signal, synchronization detection signal control, count value of the first counter, and count value of the second counter when a malfunction occurs in the polygon mirror motor. [Figure 11]Figure 11 is a time chart showing the relationship between the motor rotation speed, rotation synchronization signal, synchronization detection signal control, count value of the first counter, and count value of the second counter when the polygon mirror motor is not completely broken but there are signs of a failure. DETAILED DESCRIPTION OF THE INVENTION

[0009] The image forming apparatus according to the embodiment will be described below with reference to the drawings. Note that the scale of each part in each drawing used in the following description of the embodiment has been changed as appropriate. Also, for the sake of explanation, the configuration of each drawing used in the following description of the embodiment has been omitted as appropriate.

[0010] FIG. 1 is a schematic diagram of a printing system including a plurality of image forming apparatuses 100 according to an embodiment. The printing system further includes a plurality of user terminals 200, a server device 300, and a serviceman terminal 400. Each image forming apparatus 100 is placed in a workplace and can be communicatively connected to a user terminal 200 located in the same workplace via an internal network 500 such as a LAN (Local Area Network). This connection can be wired or wireless. The internal network 500 is also connected to an external network 600 such as the Internet. The server device 300 and the serviceman terminal 400 are connected to the external network 600. As a result, the image forming apparatus 100 can be communicatively connected to the server device 300 via the internal network 500 and the external network 600.

[0011] The user terminal 200 is an information processing device, such as a personal computer (PC), smartphone, tablet terminal, or digital camera, that instructs printing on one of the image forming apparatuses 100. The user terminal 200 may be communicatively connected to the image forming apparatus 100 via the external network 600 and the internal network 500. That is, the user terminal 200 may be located outside the workplace where the image forming apparatus 100 is located. The user terminal 200 may also be directly connected to the image forming apparatus 100, i.e., locally connected, without going through the external network 600 and the internal network 500. This local connection may also be a wired connection or a wireless connection.

[0012] Server device 300 is a computer device operated directly or by a management company contracted to perform maintenance and inspection of image forming apparatuses 100, through a service provider. Server device 300 periodically or as needed acquires data indicating the operating status of each image forming apparatus 100, or acquires notification data such as alerts sent from image forming apparatuses 100. Based on the acquired data, server device 300 determines whether each image forming apparatus 100 needs to be inspected or repaired. If an image forming apparatus 100 needs to be inspected or repaired, server device 300 transmits information identifying that image forming apparatus 100 to serviceman terminal 400, thereby enabling a serviceman to inspect or repair that image forming apparatus 100.

[0013] The serviceman terminal 400 is an information processing device such as a smartphone or tablet terminal carried by a serviceman who inspects or repairs the image forming apparatus 100. Although only one serviceman terminal 400 is shown in Fig. 1, the printing system may include multiple serviceman terminals 400. In this case, the server device 300 can assign an appropriate serviceman to the image forming apparatus 100 that requires inspection or repair based on information such as the location information of each serviceman using a location detection function provided in the serviceman terminal 400 and the availability of each serviceman.

[0014] 2 is a cross-sectional view schematically illustrating an example of the configuration of an image forming apparatus 100 according to an embodiment. The image forming apparatus illustrated in FIG. 2 is an MFP, and includes a scanner 1, a printer 2, an operation panel 4, and a system control unit 5.

[0015] The scanner 1 is a device that reads an image of an original document and converts it into image data. The scanner 1 is configured, for example, with a CCD (Charge Coupled Device) line sensor that converts an image on the reading surface of the original document into image data. The scanner 1 may have a function of scanning an original document placed on a platen glass. The scanner 1 may also have a function of reading an image of an original document conveyed by an ADF (Auto Document Feeder). The scanner 1 is installed, for example, on top of the main body of the MFP. The scanner 1 is controlled by a system control unit 5. The scanner 1 outputs the image data of the original document to the system control unit 5.

[0016] Printer 2 is an electrophotographic printer. Printer 2 forms images on paper as a recording medium. Printer 2 has a color printing function for printing color images on paper and a monochrome printing function for printing monochrome (e.g., black) images on paper. Printer 2 forms color images using toner of multiple colors (e.g., three colors: yellow (Y), cyan (C), and magenta (M)). Printer 2 also forms monochrome images using monochrome (e.g., black (K)) toner.

[0017] In the exemplary configuration shown in FIG. 2, the printer 2 has paper feed cassettes 20 (20A, 20B, 20C). The paper feed cassette 20 is a paper feed unit that supplies paper on which an image is printed. The printer 2 may also have a manual feed tray or the like as a paper feed unit. For example, each of the paper feed cassettes 20A, 20B, and 20C is detachably provided at the bottom of the MFP main body. Each of the paper feed cassettes 20A, 20B, and 20C stores paper of a set type (e.g., size, paper quality) for that cassette.

[0018] Each of the paper feed cassettes 20A, 20B, and 20C has a pickup roller 21A, 21B, and 21C, respectively. The pickup rollers 21A, 21B, and 21C pick up sheets of paper one by one from each of the paper feed cassettes 20A, 20B, and 20C. The pickup rollers 21A, 21B, and 21C then supply the picked-up sheets to a conveyance path (conveyance unit 22) that is made up of multiple conveyance rollers 22A, 22B, and 22C.

[0019] Conveying unit 22 transports paper within printer 2. For example, conveying unit 22 transports paper picked up by pickup rollers 21A, 21B, and 21C to registration rollers 24. Registration rollers 24 transport the paper to a transfer position at the timing when an image is transferred from transfer belt 27 to the paper. Conveying unit 22 transports paper that has passed through registration rollers 24 to the transfer position. Conveying unit 22 transports paper that has passed through the transfer position from the transfer position to fuser 29. Conveying unit 22 transports paper that has passed fuser 29 to either a paper discharge unit or an automatic double-sided unit (ADU).

[0020] The image forming units 25 (25Y, 25M, 25C, 25K) form images to be transferred onto paper. In the configuration example shown in FIG. 2, the image forming unit 25Y forms an image using yellow toner. The image forming unit 25M forms an image using magenta toner. The image forming unit 25C forms an image using cyan toner. The image forming unit 25K forms an image using black toner.

[0021] Each image forming unit 25 (25Y, 25M, 25C, 25K) has a photosensitive drum 30 (30y, 30m, 30c, 30k), a charger 31 (31y, 31m, 31c, 31k), a developer 32 (32y, 32m, 32c, 32k), a transfer roller 33 (33y, 33m, 33c, 33k), and a cleaner 34 (34y, 34m, 34c, 34k).

[0022] The photosensitive drum 30 is an image carrier on which an electrostatic latent image is formed. The photosensitive drum 30 rotates on a rotary shaft. The charger 31 charges the surface of the photosensitive drum 30 to a predetermined potential. The charger 31 has a grid (not shown) for adjusting the charging output to the photosensitive drum 30. The developer 32 develops the electrostatic latent image formed on the photosensitive drum 30 with toner. The transfer roller 33 transfers the toner image developed on the photosensitive drum 30 to the transfer belt 27. The cleaner 34 cleans the surface of the photosensitive drum 30 after transfer.

[0023] The exposure unit 26 forms an electrostatic latent image on the photosensitive drum 30 of each image forming unit 25 (25Y, 25M, 25C, 25K) using a laser beam. The exposure unit 26 irradiates the photosensitive drum 30 with a laser beam controlled according to image data via an optical system such as a polygon mirror. The laser beam from the exposure unit 26 forms an electrostatic latent image on the surface of each photosensitive drum 30. The exposure unit 26 controls the laser beam according to a control signal from the system control unit 5.

[0024] Each image forming unit 25 (25Y, 25M, 25C, 25K) develops the electrostatic latent image formed on each photosensitive drum 30 by each developing device 32. Each developing device 32 is equipped with a developing container having a developing roller. The developing container stores toner as a developer of each color. The toner is charged by being stirred together with the carrier in the developing container. A developing bias is applied to the developing roller. The developing roller to which the developing bias is applied supplies toner to the electrostatic latent image on the photosensitive drum 30. The electrostatic latent image on the photosensitive drum 30 is developed into a toner image by the supplied toner.

[0025] Transfer belt 27 is an intermediate transfer body. Each image forming unit 25 (25Y, 25M, 25C, 25K) transfers (primary transfer) the toner image formed on photosensitive drum 30 onto transfer belt 27 by applying a primary transfer voltage to transfer belt 27 via transfer roller 33. For example, in image forming unit 25K, transfer roller 33k transfers a toner image developed with black toner by developer 32k onto transfer belt 27. Furthermore, when forming a color image, each image forming unit 25Y, 25M, 25C, 25K transfers toner images developed with toner of each color onto transfer belt 27 in a superimposed manner.

[0026] Transfer unit 28 transfers the toner image on transfer belt 27 to paper at a secondary transfer position. The secondary transfer position is a position where the toner image on transfer belt 27 is transferred to paper. The secondary transfer position is a position where support roller 28a and secondary transfer roller 28b face each other.

[0027] The fuser 29 fuses the toner onto the paper. The fuser 29 applies heat for fusing to the paper. In the example shown in FIG. 2, the fuser 29 is composed of a heat roller 29b incorporating a heating unit 29a and a pressure roller 29c that presses against the fusing belt heated by the heat roller 29b. The heating unit 29a may be any heater capable of controlling its temperature. For example, the heating unit 29a may be composed of a heater lamp such as a halogen lamp, or may be an induction heating (IH) heater. The heating unit 29a may also be composed of multiple heaters. The fuser 29 transports the paper after the fusing process to either the paper discharge unit or the ADU.

[0028] The operation panel 4 is a user interface. The operation panel 4 has various buttons and a display unit 4a equipped with a touch panel 4b. The system control unit 5 controls the content displayed on the display unit 4a of the operation panel 4. The display unit 4a functions as a notification unit. The operation panel 4 also outputs information input to the touch panel 4b or buttons of the display unit 4a to the system control unit 5. The user uses the operation panel 4 to specify an operation mode and input information such as setting information.

[0029] Next, the configuration of the exposure unit 26 will be described.

[0030] 3 is a diagram showing an example of the configuration of the exposure unit 26 used in the image forming apparatus 100. FIG. 4 is a cross-sectional view showing an example of the configuration of the exposure unit 26 installed in the image forming apparatus 100.

[0031] 3 and 4 includes an exposure unit for each color that forms an image. In the image forming apparatus 100 that forms a color image as shown in FIG. 2, the exposure section 26 has an exposure unit for each color that forms the color image. In an image forming apparatus that forms only monochrome images, the exposure section 26 may be provided with one set of exposure units for forming monochrome images.

[0032] The exposure section 26 shown in Figures 3 and 4 includes exposure units for each color (yellow, magenta, cyan, and black) and a beam detect (BD) detection unit. Each color exposure unit includes a laser unit 40 (40y, 40m, 40c, 40k) and an optical system. Each laser unit 40 has multiple light-emitting elements. For example, it is configured as a laser array in which multiple laser diodes (LDs) are arrayed. The optical system that makes up each color exposure unit includes a mirror 41k, mirrors 42 (42m, 42c, 42k), a polygon mirror 43, lenses 44 and 45, and a mirror group 48 (48y, 48m, 48c, 48k).

[0033] The exposure unit for yellow includes a laser unit 40y, a polygon mirror 43, lenses 44 and 45, and a mirror group 48y. The laser unit 40y emits laser light for forming a yellow image. The polygon mirror 43, lenses 44 and 45, and mirror group 48y form an optical system for guiding the laser light emitted by the laser unit 40y onto the photosensitive drum 30y. The polygon mirror 43 is rotated by a polygon mirror motor 43a. As the polygon mirror 43 rotates, it scans the laser light in the main scanning direction on the photosensitive drum 30y. The main scanning direction is the direction of the rotation axis of the photosensitive drum 30y. The scanning position of the laser light emitted by the laser unit 40y moves in the sub-scanning direction on the photosensitive drum 30y due to the rotating polygon mirror 43. The sub-scanning direction is a direction perpendicular to the main scanning direction.

[0034] The magenta exposure unit includes a laser unit 40m, a mirror 42m, a polygon mirror 43, lenses 44 and 45, and a mirror group 48m. The laser unit 40m emits laser light to form a magenta image. The polygon mirror 43, lenses 44 and 45, and mirror group 48m form an optical system for guiding the laser light emitted by the laser unit 40m onto the photosensitive drum 30m. The polygon mirror 43 is rotated by a polygon mirror motor 43a. As the polygon mirror 43 rotates, it scans the laser light in the main scanning direction on the photosensitive drum 30m. The main scanning direction is the direction of the rotation axis of the photosensitive drum 30m. The scanning position of the laser light emitted by the laser unit 40m moves in the sub-scanning direction on the photosensitive drum 30m due to the rotating polygon mirror 43. The sub-scanning direction is a direction perpendicular to the main scanning direction.

[0035] The exposure unit for cyan includes a laser unit 40c, a mirror 42c, a polygon mirror 43, lenses 44 and 45, and a mirror group 48c. The laser unit 40c emits laser light to form a cyan image. The polygon mirror 43, lenses 44 and 45, and mirror group 48c form an optical system for guiding the laser light emitted by the laser unit 40c onto the photosensitive drum 30c. The polygon mirror 43 is rotated by a polygon mirror motor 43a. As the polygon mirror 43 rotates, it scans the laser light in the main scanning direction on the photosensitive drum 30c. The main scanning direction is the direction of the rotation axis of the photosensitive drum 30c. The scanning position of the laser light emitted by the laser unit 40c moves in the sub-scanning direction on the photosensitive drum 30c due to the rotating polygon mirror 43. The sub-scanning direction is a direction perpendicular to the main scanning direction.

[0036] The black exposure unit includes a laser unit 40k, mirrors 41k and 42k, a polygon mirror 43, lenses 44 and 45, and a mirror group 48k. The laser unit 40k emits laser light for forming a black image. The polygon mirror 43, lenses 44 and 45, and mirror group 48k form an optical system for guiding the laser light emitted by the laser unit 40k onto the photosensitive drum 30k. The polygon mirror 43 is rotated by a polygon mirror motor 43a. As the polygon mirror 43 rotates, it scans the laser light in the main scanning direction on the photosensitive drum 30k. The main scanning direction is the direction of the rotation axis of the photosensitive drum 30k. The scanning position of the laser light emitted by the laser unit 40k moves in the sub-scanning direction on the photosensitive drum 30k due to the rotating polygon mirror 43. The sub-scanning direction is a direction perpendicular to the main scanning direction.

[0037] The BD detection unit of the exposure unit 26 includes a mirror 46 and a BD sensor 47. The mirror 46 guides the laser light scanned by the polygon mirror 43 to the BD sensor 47. The BD sensor 47 detects the laser light from any one of the light sources in the laser unit 40. The BD sensor 47 detects the laser light as a signal (BD signal, reference signal) that serves as a reference for scanning in the main scanning direction. The BD sensor 47 is set on the scanning line along which the laser light from the LD (reference light-emitting element) to be detected is scanned. In other words, the BD sensor 47 detects that the laser light is at the reference position in the main scanning direction. The LD of each laser unit 40 controls the emission of laser light based on the BD signal detected by the BD sensor 47.

[0038] Next, the configuration of the control system of the image forming apparatus 100 will be described.

[0039] FIG. 5 is a block diagram showing an example of the configuration of the control system in the system control unit 5 and the printer 2 of the image forming apparatus 100. As shown in FIG.

[0040] In this configuration example, the system control unit 5 has a system CPU (Central Processing Unit) 51, which is a processor, RAM (Random Access Memory) 52, ROM (Read Only Memory) 53, non-volatile memory (referred to as NVM (Non-volatile Memory) in the figure) 54, HDD (Hard Disk Drive) 55, an external interface (referred to as I / F in the figure) 56, an input image processing unit 57, a page memory 58, and an output image processing unit 59.

[0041] The system CPU 51 is a control unit that performs overall control of each unit of the image forming apparatus 100. The system CPU 51 is a processor that performs processing by executing a program. The system CPU 51 is connected to each unit in the system control unit 5 via a system bus. The system CPU 51 is also connected to the scanner 1, printer 2, operation panel 4, etc. via the system bus. The system CPU 51 outputs operation instructions to each unit and obtains various information from each unit through two-way communication with the scanner 1, printer 2, and operation panel 4.

[0042] The CPU, which is a processor constituting the control unit, may be multi-core / multi-threaded and can execute multiple processes in parallel. The processor is not limited to a CPU and may be a microprocessing unit (MPU). Furthermore, the processor may be implemented in various other forms, including integrated circuits such as an application-specific integrated circuit (ASIC), a graphics processing unit (GPU), a field-programmable gate array (FPGA), a digital signal processor (DSP), a system on a chip (SoC), and a programmable logic device (PLD). The processor may also be a combination of these.

[0043] The RAM 52 is a volatile memory. The RAM 52 functions as a working memory or a buffer memory. The ROM 53 is a non-rewritable non-volatile memory that stores programs, control data, and the like. The system CPU 51 performs various processes by using the RAM 52 and executing programs stored in the ROM 53 (or the non-volatile memory 54 or the HDD 55). For example, the system CPU 51 performs functions such as issuing a print command and prohibiting printing by executing the programs.

[0044] The nonvolatile memory 54 is a rewritable nonvolatile memory. The nonvolatile memory 54 stores control programs and control data executed by the system CPU 51. The nonvolatile memory 54 also stores various setting information and processing conditions. For example, the nonvolatile memory 54 stores setting information for each paper feed cassette (paper feed unit).

[0045] The HDD 55 is a large-capacity storage device. The HDD 55 stores image data and various types of operation history information. The HDD 55 may also store control programs and control data. The HDD 55 may also store setting information and processing conditions.

[0046] The external interface 56 is an interface for communicating with an external device. For example, the external interface 56 receives a print job from the user terminal 200, which is an external device, and transmits data to the server device 300, which is also an external device. The external interface 56 may be any interface that performs data communication with an external device.

[0047] The input image processing unit 57 processes the image data read by the scanner 1. The input image processing unit 57 has functions such as shading correction processing, gradation conversion processing, inter-line correction processing, and compression / expansion processing. The input image processing unit 57 stores the processed image data in a page memory 58.

[0048] The page memory 58 is a memory for expanding image data. For example, the page memory 58 stores image data that has been processed by the input image processing unit 57 on image data read by the scanner 1. The page memory 58 may also store image data included in a print job acquired via the external interface 56.

[0049] The output image processing unit 59 generates image data for printing on paper by the printer 2. The output image processing unit 59 performs image processing to convert the image data stored in the page memory 58 into image data for printing. The output image processing unit 59 sends the image-processed data to the printer 2.

[0050] Next, an example of the configuration of the control system in the printer 2 will be described.

[0051] In the configuration example shown in Figure 5, the printer 2 has a control system configuration including a printer CPU 61, RAM 62, ROM 63, non-volatile memory (NVM) 64, a conveyance control unit 65, an exposure control unit 70, an image formation control unit 71, a transfer control unit 72, and a fixing control unit 73.

[0052] The printer CPU 61 controls the entire printer 2. The printer CPU 61 is a processor that performs processing by executing programs. The processor is not limited to a CPU, and may be realized in various other forms, including integrated circuits such as an MPU, ASIC, GPU, FPGA, DSP, SoC, and PLD. The processor may also be a combination of two or more of these. The printer CPU 61 is connected to each unit in the printer 2 via a system bus or the like. The printer CPU 61 outputs operation instructions to each unit in the printer 2 in response to operation instructions from the system CPU 51. The printer CPU 61 also notifies the system CPU 51 of information indicating the processing status of the printer 2.

[0053] The RAM 62 is a volatile memory. The RAM 62 functions as a working memory or a buffer memory. The ROM 63 is a non-rewritable non-volatile memory that stores programs, control data, and the like. The printer CPU 61 uses the RAM 62 to execute programs stored in the ROM 63 (or the non-volatile memory 64) to perform various processes.

[0054] The nonvolatile memory 64 is a rewritable nonvolatile memory. For example, the nonvolatile memory 64 stores the control program and control data executed by the printer CPU 61, and history data generated by the printer CPU 61 executing the control program. The nonvolatile memory 64 may also store setting information, processing conditions, and the like.

[0055] 6 is a block diagram showing an example of the configuration of the nonvolatile memory 64. In this embodiment, the nonvolatile memory 64 includes two counters: a first counter 641 and a second counter 642. The first counter 641 is a counter that counts the length of a deviation period when the polygon mirror motor 43a deviates from the steady rotation state after being started and transitioning to steady rotation. The second counter 642 is a counter that counts the number of times the polygon mirror motor 43a deviates from the steady rotation state and then returns to the steady rotation state.

[0056] The transport control unit 65 controls the transport of paper within the printer 2. The transport control unit 65 controls the driving of the pickup roller 21 and the transport rollers 22A, 22B, 22C of the transport unit 22. The transport control unit 65 controls the driving of the transport rollers 22A, 22B, 22C as the transport unit 22 within the printer 2 in response to an operation instruction from the printer CPU 61. For example, the printer CPU 61 instructs the transport control unit 65 to control the transport of paper in response to an instruction from the system control unit 5 to start printing.

[0057] The exposure control unit 70 controls the exposure unit 26. The exposure control unit 70 forms an electrostatic latent image on the photosensitive drum 30 (30y, 30m, 30c, 30k) of each image forming unit 25 (25Y, 25M, 25C, 25K) by the exposure unit 26 in response to an operation instruction from the printer CPU 61. For example, the exposure control unit 70 controls the laser light that the exposure unit 26 irradiates onto each photosensitive drum 30 in response to image data that the printer CPU 61 is instructed to print. For example, the exposure control unit 70 controls the scanning of the laser light emitted by each laser unit based on a BD signal obtained from the exposure unit 26.

[0058] The image formation control unit 71 controls the driving of each image forming unit 25 (25Y, 25M, 25C, 25K). For example, the image formation control unit 71 charges the photosensitive drum 30 to a predetermined potential using the charger 31. The image formation control unit 71 develops the electrostatic latent image formed on the photosensitive drum 30 after charging with a toner image of each color using the developer 32. The image formation control unit 71 controls the density of the toner to be developed by controlling the development bias and the like for the developer 32. The image formation control unit 71 transfers the toner image developed on the photosensitive drum 30 to the transfer belt 27 using the transfer roller 33. The image formation control unit 71 also cleans the surface of the photosensitive drum 30 after the transfer process using the cleaner 34.

[0059] In addition, the transfer control unit 72 controls the drive and transfer current of the transfer unit 28. The transfer control unit 72 transfers the toner image transferred onto the transfer belt 27 onto paper by the transfer unit 28 in accordance with operation instructions from the printer CPU 61. The fixing control unit 73 controls the drive of the fixing device 29. The fixing control unit 73 drives the heat roller 29b and the pressure roller 29c in accordance with operation instructions from the printer CPU 61. The fixing control unit 73 controls the surface temperature of the heat roller 29b to the fixing temperature by controlling the heating unit 29a.

[0060] In image forming apparatus 100 configured as described above, when power is turned on by operating a power switch (not shown), system CPU 51 and printer CPU 61 execute operations in accordance with their respective programs stored in ROMs 53 and 63 (or non-volatile memories 54 and 64). For example, in response to a print job received from user terminal 200, system CPU 51 instructs printer 2 to print the data indicated in the print job, or in response to a copy instruction entered by the user on touch panel 4b of operation panel 4, system CPU 51 scans an original document with scanner 1 and instructs printer 2 to print an image of the scanned original document. Furthermore, printer CPU 61 of printer 2 performs printing in response to a print instruction from system CPU 51.

[0061] In addition to this normal operation, the printer CPU 61 also performs diagnostic operations to identify defects in various parts of the printer 2. One such operation is a diagnostic operation for the polygon mirror motor 43a. FIGS. 7 and 8 are a series of flowcharts illustrating an example of the diagnostic operation for the polygon mirror motor 43a. Note that the processing shown in FIGS. 7 and 8 and described below is merely an example, and various other processes that can achieve similar results can be used as appropriate. For example, when the printer CPU 61 is powered on by turning the power switch ON, the printer CPU 61 executes this diagnostic processing based on a control program stored in the non-volatile memory 64. Note that unless otherwise specified, the processing of the printer CPU 61 transitions from ACTn (n is a natural number) to ACT(n+1).

[0062] In ACT1, the printer CPU 61 transmits the count value of the second counter 642 in the nonvolatile memory 64 to the server device 300. Specifically, the printer CPU 61 reads the count value of the second counter 642 in the nonvolatile memory 64, and requests the system CPU 51 of the system control unit 5 to transmit the count value. In response to this request, the system CPU 51 transmits the count value to the server device 300 via the external interface 56.

[0063] In ACT2, the printer CPU 61 determines whether or not to send the count value to the server device 300. Specifically, the printer CPU 61 determines whether or not there has been a count value read request from the system CPU 51. When the system CPU 51 receives a count value transmission request from the server device 300, it requests the printer CPU 61 to read this count value. Based on the determination that there has been a count value read request, i.e., that the count value will be transmitted to the server device 300 (ACT2, YES), the printer CPU 61 proceeds to the processing operation of ACT1 described above.

[0064] Based on the determination that there is no request to read the count value, i.e., that the count value will not be sent to the server device 300 (ACT2, NO), the printer CPU 61 determines in ACT3 whether or not to start printing. Specifically, the printer CPU 61 determines whether or not there has been a print instruction from the system CPU 51. Based on the determination that printing will not be started (ACT3, NO), the printer CPU 61 proceeds to the processing operation of ACT2 above.

[0065] Based on the determination that printing should be started (ACT3, YES), the printer CPU 61 determines in ACT4 whether the synchronization detection waiting period SDW has elapsed.

[0066] FIG. 9 is a time chart showing the relationship between the motor rotation speed, the rotation synchronization signal, and the synchronization detection control when the polygon mirror motor 43a is normal.

[0067] At time t0, when printing begins, the printer CPU 61 sends a rotation-on signal to the polygon mirror motor 43a of the exposure unit 26. In response to this rotation-on signal, the polygon mirror motor 43a begins to rotate. A target rotation speed range TRR is determined according to a clock supplied from the printer CPU 61 to the polygon mirror motor 43a or a clock provided within the polygon mirror motor 43a. As the rotation speed of the polygon mirror motor 43a increases, when the rotation speed enters the target rotation speed range TRR, the polygon mirror motor 43a enters steady rotation. While the rotation speed of the polygon mirror motor 43a is within the target rotation speed range TRR, a rotation synchronization signal is sent from the polygon mirror motor 43a to the printer CPU 61. The printer CPU 61 detects this rotation synchronization signal and continues the printing operation.

[0068] However, it takes time for the polygon mirror motor 43a to reach a steady rotation speed after it starts rotating. Therefore, the synchronization detection operation in the printer CPU 61 does not start immediately after outputting the rotation-on signal, but waits for a fixed time t1 before starting. This waiting period until time t1 is the synchronization detection waiting period SDW.

[0069] Returning to the explanation of Figure 8. Based on the determination that the synchronization detection wait period SDW has not elapsed (ACT4, NO), the printer CPU 61 repeats the processing operation of ACT4. That is, the printer CPU 61 continues the processing operation of ACT4 until it determines that the synchronization detection wait period SDW has elapsed. In other words, the printer CPU 61 waits for the synchronization detection wait period SDW to elapse.

[0070] Based on the determination at time t1 that the synchronization detection waiting period SDW has elapsed (ACT4, YES), the printer CPU 61 starts the synchronization determination operation in ACT5.

[0071] Basically, in the synchronization detection control shown in FIG. 9, the printer CPU 61 determines whether the polygon mirror motor 43a is synchronized based on the rotation synchronization signal output from the polygon mirror motor 43a when the high state is reached. Specifically, the printer CPU 61 determines whether the rotation synchronization signal sent from the polygon mirror motor 43a is low. The printer CPU 61 performs this synchronization determination operation at predetermined regular intervals. This regular interval is set to a time, for example, from several seconds to 30 seconds, to prevent erroneous detection, and is stored in the non-volatile memory 64.

[0072] In ACT6, the printer CPU 61 determines whether synchronization of the polygon mirror motor 43a has been detected at the time set as the regular interval. Specifically, the printer CPU 61 determines whether a rotation synchronization signal is being output from the polygon mirror motor 43a, that is, whether the rotation synchronization signal is in the low state. If synchronization is not detected (ACT6, NO), the printer CPU 61 repeats the processing operation of ACT6. By continuing the processing operation of ACT6 in this way, the printer CPU 61 determines whether synchronization has been detected at each time set as the regular interval. In other words, the printer CPU 61 waits for the polygon mirror motor 43a to enter a synchronized state.

[0073] As shown in FIG. 9, at time t2, which is the first synchronization determination timing after the rotation speed of the polygon mirror motor 43a reaches the target rotation speed range TRR and the rotation synchronization signal goes low, the printer CPU 61 determines that synchronization has been detected.

[0074] Based on the determination that synchronization has been detected (ACT6, YES), the printer CPU 61 determines in ACT7 whether the synchronization determination wait period SJW has elapsed. Based on the determination that the synchronization determination wait period SJW has not elapsed (ACT7, NO), the printer CPU 61 repeats the processing operation of ACT7. That is, the printer CPU 61 continues the processing operation of ACT7 until it determines that the synchronization determination wait period SJW has elapsed. It can also be said that the printer CPU 61 waits for the synchronization determination wait period SJW to elapse.

[0075] Even when the rotation speed of the polygon mirror motor 43a enters the target rotation speed range TRR, the motor rotation speed does not immediately stabilize in the steady rotation range SSR. That is, as shown in Figure 9, when the motor rotation speed first reaches the target rotation speed range TRR, the rotation overshoots. Therefore, the rotation speed is adjusted to maintain the target rotation speed range TRR. During this adjustment period, the motor rotation speed fluctuates and becomes unstable. The rotation synchronization signal is turned on and off multiple times, and then the motor finally maintains steady rotation. If the polygon mirror motor 43a does not rotate at a steady speed, the scanning speed of the laser beam rotating and scanning the polygon mirror becomes unstable, resulting in distortion in the print. Therefore, the printer CPU 61 must wait the time equivalent to the unstable rotation speed range USR after the rotation speed of the polygon mirror motor 43a reaches the target rotation speed range TRR before performing a printing operation. The unstable rotation speed range USR is calculated based on parameters such as the performance of the polygon mirror motor 43a and the weight of the polygon mirror 43, and is stored in the non-volatile memory 64 as setting information for each image forming apparatus 100. For example, the unstable rotation speed region USR is about 0.5 seconds to 1.5 seconds.

[0076] The synchronization determination wait period SJW corresponds to the time in this unstable rotation speed region USR. Based on the determination that the synchronization determination wait period SJW has elapsed (ACT7, YES), the printer CPU 61 determines in ACT8 whether synchronization of the polygon mirror motor 43a has been detected at the time set as the regular interval.

[0077] 9, the printer CPU 61 detects synchronization at time t3, which is the timing when the synchronization detection control signal first rises to a high state after the synchronization determination wait period SJW has elapsed since time t2. Based on this determination that synchronization has been achieved (ACT8, YES), the printer CPU 61 determines in ACT9 whether printing has ended, that is, whether the polygon mirror motor 43a has stopped. Based on the determination that printing has not ended (ACT9, NO), the printer CPU 61 proceeds to the processing operation of ACT8.

[0078] In this way, if the printer CPU 61 detects synchronization of the polygon mirror motor 43a after the synchronization determination wait period SJW has elapsed, it will perform synchronization detection at regular intervals until printing is completed. The period during which synchronization detection is performed at regular intervals, starting from the synchronization detection timing after the synchronization determination wait period SJW has elapsed, is defined as the synchronization determination period SJP.

[0079] Based on the determination that printing during this synchronization determination period SJP is to be completed (ACT11, YES), the printer CPU 61 proceeds to the processing operation of ACT2.

[0080] FIG. 10 is a timing chart showing the relationship between the motor rotation speed, rotation synchronization signal, synchronization detection signal control, count values ​​of the first counter 641, and count values ​​of the second counter 642 when the polygon mirror motor 43a fails. When a malfunction occurs in the polygon mirror motor 43a, the motor rotation speed gradually decreases and falls outside the target rotation speed range TRR. In this case, as shown in FIG. 10, the rotation synchronization signal goes high when the motor rotation speed falls outside the target rotation speed range TRR. At time t11, which is the first synchronization determination timing after the rotation synchronization signal goes high, the printer CPU 61 determines that synchronization is not detected.

[0081] Based on this determination that synchronization has not been detected (ACT8, YES), the printer CPU 61 determines in ACT10 whether the count value of the first counter 641 in the nonvolatile memory 64 is the default value, "3" in this example. Here, the count value of the first counter 641 is initially set to "0." Therefore, at this time t11, the printer CPU 61 determines that the count value of the first counter 641 is not the default value of "3."

[0082] Based on the determination that the count value of the first counter 641 is not the default value of "3" (ACT10, NO), the printer CPU 61 increments the count value of the first counter 641 in ACT11. As a result, the count value of the first counter 641 changes from "0" to "1."

[0083] In ACT12, the printer CPU 61 determines whether or not synchronization of the polygon mirror motor 43a is detected at the time set as the regular interval, i.e., at time t12. If synchronization is not detected (ACT12, NO), the printer CPU 61 proceeds to the processing operation of ACT10.

[0084] As a result, in ACT10, the printer CPU 61 determines whether the count value of the first counter 641 is the default value of "3." Here, the count value of the first counter 641 is "1," so in ACT11, the count value of the first counter 641 is updated from "1" to "2." Then, at time t13 when the regular interval has elapsed, the printer CPU 61 determines in ACT12 whether synchronization of the polygon mirror motor 43a has been detected. In this case, too, it is determined that synchronization has not been detected, and the printer CPU 61 proceeds to the processing operation of ACT10.

[0085] Similarly, in ACT10, the printer CPU 61 determines whether the count value of the first counter 641 is the default value of "3." Here, the count value of the first counter 641 is "2," so in ACT11, the count value of the first counter 641 is updated from "2" to "3." Then, at time t14 when the regular interval has elapsed, the printer CPU 61 determines in ACT12 whether synchronization of the polygon mirror motor 43a has been detected. In this case, too, it is determined that synchronization has not been detected, and the printer CPU 61 proceeds to the processing operation of ACT10.

[0086] In this case, the count value of the first counter 641 is "3," so in ACT 10, the printer CPU 61 determines that the count value of the first counter 641 is the default value of "3." Based on this determination that the count value of the first counter 641 is "3" (ACT 10, YES), the printer CPU 61 stops the operation of the printer 2 in ACT 13.

[0087] In ACT14, the printer CPU 61 notifies the system CPU 51 of the motor abnormality. Then, the printer CPU 61 ends operation. Upon receiving this notification of the motor abnormality, the system CPU 51 displays on the display unit 4a of the operation panel 4 that the polygon mirror motor 43a has broken down and printing is not possible. Upon seeing this display, the user can request repairs from a maintenance inspection company. The system CPU 51 may also notify the server device 300 of the motor abnormality via the external interface 56. This allows the server device 300 to arrange for repairs of the image forming device 100 via the serviceman terminal 400.

[0088] As described above, after starting the polygon mirror motor 43a, the printer CPU 61 detects the motor rotation synchronization signal, and if it determines that the rotation speed of the polygon mirror motor 43a has reached the target rotation speed range TRR, it continues to detect the rotation synchronization signal at regular intervals.The printer CPU 61 then counts the number of consecutive times that it has not detected a synchronization signal within the regular interval using the first counter 641 as a rotation abnormality counter, and if the count value reaches a preset value, it determines that an abnormality such as a breakdown has occurred in the polygon mirror motor 43a, and terminates the operation of the polygon mirror motor 43a and its own operation.

[0089] Note that a malfunction of the polygon mirror motor 43a may also occur in which rotation suddenly stops and the motor locks up. When such a malfunction occurs, the printer CPU 61 can stop the operation of the printer 2 in ACT 13 and notify the system CPU 51 of the motor malfunction in ACT 14, just as in the malfunction pattern shown in Figure 10, when the count value of the first counter 641 reaches the specified value of "3".

[0090] Furthermore, the rotation failure of the polygon mirror motor 43a can also occur in the following pattern: the rotation of the polygon mirror motor 43a temporarily becomes unstable and then returns to a stable state, repeatedly, the rotation characteristics gradually deteriorate, the time required to return to a stable state increases, and finally, the motor is unable to return to a stable state, resulting in a state in which it is ultimately determined to have failed, as shown in Figure 10. In this embodiment, the state in which the rotation characteristics gradually deteriorate and the rotation becomes unstable, prior to the state in which it is ultimately determined to have failed, is detected as a sign of failure in the following manner.

[0091] 11 is a time chart showing the relationship between the motor rotation speed, rotation synchronization signal, synchronization detection signal control, count value of the first counter 641, and count value of the second counter 642 when the polygon mirror motor 43a is not completely broken but there are signs of a failure. In this case, when the polygon mirror motor 43a is rotating within the target rotation speed range TRR and the rotation speed drops and falls outside the target rotation speed range TRR, the rotation speed is controlled so as to return to the target rotation speed range TRR, and this process of returning to the target rotation speed range TRR is repeated.

[0092] Therefore, as shown in FIG. 11, at time t21, which is the first synchronization determination timing after the rotation speed of the polygon mirror motor 43a decreases and falls outside the target rotation speed range TRR, and the rotation synchronization signal goes high, the printer CPU 61 determines that synchronization is not detected.

[0093] Based on this determination that synchronization has not been detected (ACT8, YES), as described above, the printer CPU 61 determines in ACT10 whether the count value of the first counter 641 in the nonvolatile memory 64 is the default value, in this example, "3." Here, since the count value of the first counter 641 is initially set to "0," in ACT11 the count value of the first counter 641 is updated from "0" to "1."

[0094] Then, at time t22 after the regular interval has elapsed, the printer CPU 61 determines in ACT 12 whether synchronization of the polygon mirror motor 43a has been detected. At this time, as shown in Figure 11, the rotation speed control is attempting to bring the polygon mirror motor 43a into the target rotation speed range TRR, but the rotation speed has not yet reached the target rotation speed range TRR. Therefore, the rotation synchronization signal remains high, and the printer CPU 61 determines that synchronization has not been detected.

[0095] Based on the determination that synchronization has not been detected (ACT12, NO), the printer CPU 61 proceeds to the processing operation of ACT 10. As a result, in ACT 10, the printer CPU 61 determines whether the count value of the first counter 641 is the default value of "3." Here, since the count value of the first counter 641 is "1," in ACT 11, the count value of the first counter 641 is updated from "1" to "2."

[0096] Then, at time t23 when the regular interval has elapsed, the printer CPU 61 determines whether or not synchronization of the polygon mirror motor 43a has been detected in ACT 12. At this time, as shown in Figure 11, if the rotation speed of the polygon mirror motor 43a has returned to the target rotation speed range TRR, the rotation synchronization signal will be low, and synchronization will be detected.

[0097] Based on the determination that synchronization has been detected (ACT12, YES), the printer CPU 61 resets the count value of the first counter 641 to "0" in ACT15.

[0098] In ACT16, the printer CPU 61 increments the count value of the second counter 642 in the nonvolatile memory 64. The count value of the second counter 642 is initially set to "0." Therefore, at time t23, the count value of the second counter 642 changes from "0" to "1."

[0099] In ACT17, the printer CPU 61 determines whether the count value of the second counter 642 has reached a specified number. If the specified number is too high, the system may progress to a complete failure state before any signs of failure are detected, so it is preferable to set the specified number to between several and a dozen. This specified number is stored in the non-volatile memory 64 as setting information for each image forming apparatus 100. If the count value of the second counter 642 is "1," the printer CPU 61 determines that the count value of the second counter 642 has not reached the specified number. Based on this determination (ACT17, NO), the printer CPU 61 proceeds to the processing operation of ACT8 above.

[0100] 11, at time t24, which is the time set as the next regular interval, the rotation speed of the polygon mirror motor 43a has returned to the target rotation speed range TRR. Therefore, at this time t24 and thereafter, the printer CPU 61 repeats the processing operations of ACT8 and ACT9 described above. Therefore, the count value of the first counter 641 is maintained at "0," and the count value of the second counter 642 is maintained at "2."

[0101] In the example shown in FIG. 11, after an arbitrary time has elapsed, the rotation of the polygon mirror motor 43a deviates from the target rotation speed range TRR and then returns to the target rotation speed range TRR, causing the rotation synchronization signal to temporarily go high.

[0102] When synchronization determination is performed at time t31, when this high state occurs, it is determined that synchronization has not been detected. Based on this determination that synchronization has not been detected (ACT8, YES), the printer CPU 61 determines in ACT10 whether the count value of the first counter 641 in the non-volatile memory 64 is the default value, in this example, "3." Here, the count value of the first counter 641 has been reset to "0," so in ACT11, the count value of the first counter 641 is updated from "0" to "1." At this time t31, no operation has been performed on the second counter 642, so the count value of "1" is maintained.

[0103] Then, at time t32 after the regular interval has elapsed, the printer CPU 61 determines in ACT 12 whether synchronization of the polygon mirror motor 43a has been detected. At this time, as shown in Figure 11, the rotation speed of the polygon mirror motor 43a has returned to the target rotation speed range TRR, and the rotation synchronization signal is in the low state. Therefore, synchronization is detected.

[0104] Based on the determination that synchronization has been detected (ACT12, YES), the printer CPU 61 resets the count value of the first counter 641 to "0" in ACT15.

[0105] In ACT16, the printer CPU 61 increments the count value of the second counter 642 in the nonvolatile memory 64. Thus, at this time t32, the count value of the second counter 642 changes from "1" to "2."

[0106] In ACT17, the printer CPU 61 determines whether the count value of the second counter 642 has reached the specified number of times, and if the count value of the second counter 642 is "2", it determines that the count value has not reached the specified number of times. Based on this determination (ACT17, NO), the printer CPU 61 proceeds to the processing operation of ACT8.

[0107] In the example shown in Figure 11, at time t33, which is the time set as the next regular interval, and at any time thereafter, the rotation speed of the polygon mirror motor 43a is stable within the target rotation speed range TRR. Therefore, the printer CPU 61 repeats the processing operations of ACT8 and ACT9 described above. Therefore, the count value of the first counter 641 is maintained at "0," and the count value of the second counter 642 is maintained at "2."

[0108] In this way, during the current printing or subsequent printing operations, the count value of the second counter 642 is incremented each time the rotation speed temporarily falls outside the target rotation speed range TRR.

[0109] Based on the determination that the count value of the second counter 642 has reached the specified number of times (ACT 17, YES), the printer CPU 61 notifies the system CPU 51 of a motor abnormality sign in ACT 18. The notification of the motor abnormality sign includes the count value of the second counter 642. Thereafter, the printer CPU 61 proceeds to the processing operation of ACT 8 above.

[0110] Upon receiving the notification of the motor abnormality warning, the system CPU 51 displays the count value included in the notification or displays an alert based on the count value on the display unit 4a of the operation panel 4. A user who sees this display can request an inspection from a maintenance inspection company. The system CPU 51 may also transmit the motor abnormality warning notification including the count value or the alert content to the server device 300 via the external interface 56. This allows the server device 300 to arrange for an inspection of the image forming apparatus 100 via the serviceman terminal 400.

[0111] As described above, if the printer CPU 61 fails to detect the rotation synchronization signal of the polygon mirror motor 43a rotating within the target rotation speed range TRR fewer times (e.g., 1 or 2 times) than the consecutive number of times (e.g., 3 times) required for determining a malfunction, the printer CPU 61 determines that a malfunction has occurred in the polygon mirror motor 43a, but that the motor is still rotating and is therefore usable, even if there are some defects in the image, and continues printing. However, at this time, the printer CPU 61 increments the count value of the second counter 642, which serves as a motor abnormality possibility counter, and stores the count value in a non-volatile manner. In this way, the second counter 642 can count the number of times a temporary synchronization failure has occurred. Then, when the count value of the second counter 642 reaches a predetermined number, the printer CPU 61 determines that the polygon mirror motor 43a is currently usable but may eventually become unusable, and provides the count value of the second counter 642 to the system CPU 51. This allows the system CPU 51 to display the count value directly or an alert based on the count value on the display unit 4a of the operation panel 4, or to transmit the count value or the content of the alert to the server device 300.

[0112] Therefore, a user who sees the display or server device 300 who receives the count value or the alert content can arrange for a serviceman to repair the image forming apparatus 100 while the image forming apparatus 100 is still usable. This makes it possible to prevent the image forming apparatus 100 from becoming unusable due to a complete failure of polygon mirror motor 43a, or to shorten the period of unusable time until repair even if the image forming apparatus 100 breaks down before repair can actually be performed.

[0113] As described above, the printer CPU 61 of the image forming apparatus 100 according to this embodiment, which forms an image by scanning a laser beam onto the photosensitive drum 30 with the polygon mirror 43 rotated by the polygon mirror motor 43a, repeatedly determines at regular intervals whether the rotation speed of the polygon mirror motor 43a is within the target rotation speed range TRR after the polygon mirror motor 43a is started and transitions to steady rotation within the target rotation speed range TRR. In this way, the printer CPU 61 functions as a first determination unit. Furthermore, the printer CPU 61 determines that the polygon mirror motor 43a is faulty when the rotation speed falls outside the target rotation speed range TRR a predetermined number of times in succession. In this way, the printer CPU 61 functions as a second determination unit. Furthermore, when the rotation speed returns from outside the target rotation speed range TRR to within the target rotation speed range TRR within a predetermined number of consecutive times, the printer CPU 61 stores the number of times in, for example, nonvolatile memory 64. In this way, the printer CPU 61 and the nonvolatile memory 64 function as storage units. As described above, in the image forming apparatus 100 according to this embodiment, after the polygon mirror motor 43a is started and transitions to steady rotation within the target rotation speed range TRR, the printer CPU 61 periodically checks whether the rotation speed of the polygon mirror motor 43a is within the target rotation speed range TRR. If the rotation speed falls outside the target rotation speed range TRR but returns to the target rotation speed range TRR within a specified number of consecutive times, the printer CPU 61 stores the number of times in the nonvolatile memory 64. Therefore, by checking the number of times stored in the nonvolatile memory 64, it is possible to determine whether or not an abnormality, such as a malfunction, of the polygon mirror motor 43a may occur before the polygon mirror motor 43a completely fails. If an abnormality is detected, an inspection of the polygon mirror motor 43a can be requested. This prevents the image forming apparatus 100 from becoming unusable due to a complete malfunction of the polygon mirror motor 43a, or, if the polygon mirror motor 43a does not function properly before repairs can be performed, shortens the period of unusable operation until repairs are performed.

[0114] Here, the image forming apparatus 100 according to this embodiment includes a second counter 642 that counts the number of times the rotation speed returns from outside the target rotation speed range TRR to within the target rotation speed range TRR less than a specified number of times in succession. Therefore, by using the second counter 642, the image forming apparatus 100 according to this embodiment can easily store the number of times that the rotation speed of the polygon mirror motor 43a falls outside the target rotation speed range TRR and returns to within the target rotation speed range TRR within less than the specified number of consecutive times.

[0115] Furthermore, the printer CPU 61 counts the number of consecutive times that it has determined that the rotation speed is outside the target rotation speed range TRR using a first counter 641, and resets the first counter 641 when it determines that the rotation speed is within the target rotation speed range TRR. When the number of times counted by the first counter 641 reaches a specified number of consecutive times, it determines that the polygon mirror motor 43a has failed. Therefore, the image forming apparatus 100 according to this embodiment can easily count the number of consecutive times that the rotation speed of the polygon mirror motor 43a falls within the target rotation speed range TRR using the first counter 641, and can easily determine whether the polygon mirror motor 43a has failed based on this counted number of consecutive times.

[0116] In this case, the image forming apparatus 100 includes a second counter 642 that counts the number of resets of the first counter 641. Therefore, the image forming apparatus 100 according to this embodiment uses the second counter 642 to count the number of resets of the first counter 641, and can easily store the number of times the rotation speed of the polygon mirror motor 43a falls outside the target rotation speed range TRR and returns to within the target rotation speed range TRR within a specified number of consecutive times.

[0117] In addition, when the polygon mirror motor 43a is rotating within the target rotation speed range TRR, it outputs a rotation synchronization signal, and the printer CPU 61 detects the rotation synchronization signal at regular intervals to determine whether the rotation speed of the polygon mirror motor 43a is within the target rotation speed range TRR. Therefore, the image forming apparatus 100 according to this embodiment can easily determine whether the rotation speed of the polygon mirror motor 43a is within the target rotation speed range TRR by using the rotation synchronization signal from the polygon mirror motor 43a.

[0118] Moreover, the image forming apparatus 100 according to this embodiment further includes a display unit 4a that displays the number of times data has been saved in the nonvolatile memory 64. In this way, the display unit 4a functions as a display unit. Therefore, the image forming apparatus 100 according to this embodiment allows the user to check the number of times that the rotation speed of the polygon mirror motor 43a has fallen out of the target rotation speed range TRR and returned to within the target rotation speed range TRR within a specified number of consecutive times or less, and allows the user to easily determine whether or not to request inspection of the polygon mirror motor 43a. In addition, a service technician who has been requested to inspect the polygon mirror motor 43a can easily check this number of times.

[0119] Alternatively, the image forming apparatus 100 according to this embodiment further includes an external interface 56 that transmits the number of times stored in the nonvolatile memory 64 to the server device 300 via the external network 600. In this way, the external interface 56 functions as a communication means. Therefore, the image forming apparatus 100 according to this embodiment transmits to the server device 300 the number of times that the rotation speed of the polygon mirror motor 43a falls outside the target rotation speed range TRR and returns to within the target rotation speed range TRR within a specified number of consecutive times or less, thereby enabling the server device 300 to determine whether or not there is a possibility of an abnormality, such as a breakdown, occurring in the polygon mirror motor 43a based on the number of times.

[0120] Although the above embodiment has been described, the embodiment is not limited to this. For example, in the above embodiment, the count value of second counter 642 in ACT1 is transmitted to server device 300 when power is turned on and when a request is received from server device 300. However, transmission may not be performed when power is turned on. Instead, the count value may be transmitted at some specified time, such as by starting a timer in image forming apparatus 100 at a specified time, such as midnight, and transmitting the count value to server device 300 at that time. Furthermore, the count value may be transmitted based on conditions other than time, such as every time the count value of second counter 642 is incremented or every time the count value of second counter 642 increases by a certain number of times since the previous transmission.

[0121] Furthermore, in the above embodiment, the image forming apparatus 100 is provided with two processors, the system CPU 51 and the printer CPU 61. However, it goes without saying that the image forming apparatus 100 may be configured to perform various processing operations using a single processor.

[0122] In the above embodiment, the control program is pre-stored in the non-volatile memory 64 of the printer 2 of the image forming apparatus 100. In this regard, the control program, which is transferred separately from the image forming apparatus, may be written to a writable storage device provided in the image forming apparatus 100 in response to an operation by an administrator or the like. The transfer of the control program, etc., may be performed by storing it in a removable computer-readable storage medium or by communication via a network. The computer-readable storage medium may take any form, such as a CD-ROM or memory card, as long as it can store the program and is readable by the device.

[0123] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope of the invention and the scope of the inventions and their equivalents as defined in the claims. The inventions described in the original claims of this application are set forth below. [1] An image forming apparatus that forms an image by scanning a laser beam onto a photosensitive member using a polygon mirror rotated by a polygon mirror motor, a first determination means for repeatedly determining at regular intervals whether the rotation speed of the polygon mirror motor is within the target rotation speed range after the polygon mirror motor is started and has transitioned to a steady rotation within the target rotation speed range; a second determination means for determining that the polygon mirror motor has failed when the rotation speed falls outside the target rotation speed range for a specified number of consecutive times; a storage means for storing the number of times when the rotation speed returns from outside the target rotation speed range to within the target rotation speed range less than the specified number of times in succession; An image forming apparatus comprising: [2] The storage means includes a counter that counts the number of times the engine has returned from outside the target rotation speed range to within the target rotation speed range within less than the specified number of consecutive times. [1] The image forming apparatus according to [1]. [3] The second determination means: a first counter is used to count the number of consecutive times that the first determination means determines that the rotation speed is outside the target rotation speed range, and the first counter is reset when the first determination means determines that the rotation speed is within the target rotation speed range; When the number of times counted by the first counter reaches the specified number of consecutive times, it is determined that the polygon mirror motor has failed. [1] The image forming apparatus according to [1]. [4] The storage means includes a second counter that counts the number of resets of the first counter. [3] The image forming apparatus according to [3]. [5] When the polygon mirror motor is rotating within the target rotation speed range, it outputs a rotation synchronization signal; the first determination means detects the rotation synchronization signal at the regular intervals to determine whether the rotation speed of the polygon mirror motor is within the target rotation speed range; [1] The image forming apparatus according to [1]. [6] The device further includes a communication unit that transmits the number of times the storage unit has stored the information to a server device via a network. [1] The image forming apparatus according to [1]. [Explanation of symbols]

[0124] REFERENCE SIGNS LIST 1...scanner, 2...printer, 4...operation panel, 4a...display unit, 4b...touch panel, 5...system control unit, 25, 25Y, 25M, 25C, 25K...image forming unit, 26...exposure unit, 27...transfer belt, 28...transfer unit, 28a...support roller, 28b...secondary transfer roller, 29...fuser, 29a...heating unit, 29b...heat roller, 29c...pressure roller, 30, 30y, 30m, 30c, 30k...photosensitive drum, 31, 31y, 31m, 31c, 31k...charger, 32, 32y, 32m, 32c, 32k...developer, 33, 33y, 33m, 33c, 33k...transfer roller, 34, 34y, 34m, 34c, 34k...cleaner, 40, 40y, 40m, 40c, 40k...laser unit, 41k, 42, 42m, 42c, 42k...mirror, 43...polygon mirror, 43a...polygon mirror motor, 44, 45...lens, 46...mirror, 47...BD sensor, 48, 48y, 48m, 48c, 48k...mirror group, 51...system CPU, 52, 62...RAM, 53, 63...ROM, 54, 64...non-volatile memory (NVM), 55...HDD, 56...external interface (I / F), 57...input image processing unit, 58...page memory, 59...output image processing unit, 61...printer CPU, 65...conveyance control unit, 70...exposure control unit, 71...image formation control unit, 72...Transfer control unit, 73...Fusing control unit, 100...Image forming apparatus, 200...User terminal, 300...Server device, 400...Serviceman terminal, 500...In-house network, 600...External network, 641...First counter, 642...Second counter, MST...Motor start time, SDW...Synchronization detection waiting period, SJP...Synchronization judgment period, SJW...Synchronization judgment waiting period, SSR...Steady rotation region, TRR...Target rotation speed range, USR...Unstable rotation speed region.

Claims

1. An image forming apparatus that forms an image by scanning a laser beam onto a photosensitive member using a polygon mirror rotated by a polygon mirror motor, a first determination means for repeatedly determining at regular intervals whether the rotation speed of the polygon mirror motor is within the target rotation speed range after the polygon mirror motor is started and has transitioned to a steady rotation within the target rotation speed range; a second determination means for determining that the polygon mirror motor has failed when the number of rotations of the polygon mirror motor falls outside the target rotation number range for a specified number of consecutive times while the polygon mirror motor is rotating at a steady rate; a storage means for storing the number of times when the polygon mirror motor returns from outside the target rotation speed range to within the target rotation speed range less than the specified number of times in succession while the polygon mirror motor is rotating at the steady state; a third determination means for determining that the stored number of times has reached a specified number of times while the polygon mirror motor is rotating at a steady state, as a sign of a malfunction of the polygon mirror motor; An image forming apparatus comprising:

2. the storage means includes a counter that counts the number of times the engine has returned from outside the target rotational speed range to within the target rotational speed range less than the specified number of consecutive times; the third determination means determines that the number of counts by the counter reaches the specified number as a sign of a malfunction of the polygon mirror motor; The image forming apparatus according to claim 1 .

3. The second determination means a first counter is used to count the number of consecutive determinations by the first determination means that the rotation speed is outside the target rotation speed range, and the first counter is reset when the first determination means determines that the rotation speed is within the target rotation speed range; When the number of times counted by the first counter reaches the specified number of consecutive times, it is determined that the polygon mirror motor has failed. The image forming apparatus according to claim 1 .

4. the storage means includes a second counter that counts the number of resets of the first counter; the third determination means determines that the number of counts by the second counter reaches the specified number as a sign of a malfunction of the polygon mirror motor; The image forming apparatus according to claim 3 .

5. the polygon mirror motor outputs a rotation synchronization signal when rotating within the target rotation speed range; the first determination means detects the rotation synchronization signal at the regular intervals to determine whether the rotation speed of the polygon mirror motor is within the target rotation speed range; The image forming apparatus according to claim 1 .

6. A printing system comprising: an image forming device that forms an image by scanning laser light onto a photosensitive body using a polygon mirror rotated by a polygon mirror motor; and a server device that communicates with the image forming device via a network, the image forming apparatus, a first determination means for repeatedly determining at regular intervals whether the rotation speed of the polygon mirror motor is within the target rotation speed range after the polygon mirror motor is started and has transitioned to a steady rotation within the target rotation speed range; a second determination means for determining that the polygon mirror motor has failed when the number of rotations of the polygon mirror motor falls outside the target rotation number range for a specified number of consecutive times while the polygon mirror motor is rotating at a steady rate; a storage means for storing the number of times when the polygon mirror motor returns from outside the target rotation speed range to within the target rotation speed range less than the specified number of times in succession while the polygon mirror motor is rotating at the steady state; a communication means for transmitting the number of times the storage means has stored data to the server device via the network; Equipped with the server device further comprises a third determination means for determining, when the number of times transmitted from the image forming device reaches a specified number, that the number of times is a sign of a malfunction of the polygon mirror motor included in the image forming device. Printing system.

Images