Image forming apparatus

Abstract

To provide an image forming apparatus that can determine the type, such as a manufacturer, of a motor substrate installed in the image forming apparatus without providing wiring dedicated to specifying the manufacturer between a controller and the motor substrate.SOLUTION: A polygon motor substrate 78, which is one of a first polygon motor substrate 78A and a second polygon motor substrate 78B, can be mounted in a printer 10. An application specific integrated circuit (ASIC) 72 has a polygon motor terminal 102 connected to the polygon motor substrate 78 via wiring 125. The ASIC 72 causes the polygon motor terminal 102 to switch and output an ON-signal ON for rotating the polygon motor terminal 102 (S2, S7), and determines the type of the polygon motor substrate 78 according to whether a polygon motor 89 is rotated (S8).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present application relates to an image forming apparatus that includes a motor board on which a motor that rotates a drive unit is mounted, and to an image forming apparatus that determines the type of the included motor board. [Background technology]

[0002] For example, the controller board of an image forming apparatus described in Patent Document 1 (JP 2015-197820 A) is connected to a peripheral board via a cable and determines the type of the peripheral board. The cable transmits an output signal from a photointerrupter mounted on the peripheral board to a first port and a second port of a CPU on the controller board. The CPU determines the type of the peripheral board based on the voltage of the output signal input to the first port when the second port is set to a high impedance state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2015-197820 Summary of the Invention [Problem to be solved by the invention]

[0004] The controller of an image forming apparatus identifies a specific motor board from among peripheral boards provided by multiple manufacturers and determines whether to install the selected motor board in the apparatus. Furthermore, the controller must set appropriate control parameters according to the motor board installed in the image forming apparatus. Therefore, the controller must accurately determine which manufacturer's motor board is installed in the image forming apparatus. However, if a dedicated communication line is provided between the controller and the motor board to transmit information identifying the manufacturer of the motor board in order to determine the manufacturer of the motor board, problems may arise regarding how to route the wiring. For this reason, there is a need for a technology that can determine the type of motor board without the need for a dedicated communication line for transmitting information identifying the manufacturer of the motor board between the controller and the motor board.

[0005] The present application has been proposed in view of the above-mentioned problems, and aims to provide an image forming device that can determine the manufacturer and type of motor board that the image forming device has, without installing dedicated wiring between the controller and the motor board to identify the manufacturer. [Means for solving the problem]

[0006] In order to achieve the above object, the image forming apparatus of the present application is an image forming apparatus that forms an image on a sheet, and is equipped with a drive unit, a motor board on which a motor that rotates the drive unit is mounted, and a controller, wherein the motor board can be fitted with any one motor board selected from a plurality of types of motor boards, and the controller has an output terminal that is connected via wiring to the motor board fitted to the image forming apparatus, outputs a control signal for rotating the motor from the output terminal, and is capable of switching and outputting control signals according to at least the number of types of motor boards.

[0007] According to this, the motor board mounted on the image forming apparatus and the output terminal of the controller are connected by wiring, and the controller outputs a control signal by switching from the output terminal to the controller, thereby determining the type of the mounted motor board based on whether or not the drive unit is rotating. Based on the determination result, control parameters according to the type of motor can be used for control. Furthermore, because the controller outputs control signals by switching them from a single output terminal that outputs a control signal for rotating the motor, the controller can determine the type of motor board without adding dedicated wiring between the controller and the motor board to determine the type of motor board, such as the manufacturer.

[0008] The controller may also be configured to output the control signal from the output terminal and determine the type of motor board mounted based on whether or not the motor is rotating.

[0009] According to this, the controller outputs a control signal from the output terminal in a switched manner, and it is possible to determine the type of motor board that is installed based on whether the motor is rotating or not.

[0010] The controller may also be configured to be capable of outputting a Start signal indicating the start of rotational drive or a Stop signal instructing the motor driver of a motor board attached to the image forming apparatus via the output terminal, and to output a control signal indicating the Start signal from the output terminal.

[0011] This allows the controller to determine the type of motor board by outputting multiple control signals using an output terminal that outputs a Start signal to the motor driver, which indicates the start of rotational drive, or a Stop signal, which instructs the motor driver to stop, thereby eliminating the need for dedicated wiring to determine the motor board.

[0012] The image forming unit further includes an image forming section that forms an image on a sheet, the image forming section including a semiconductor laser, a polygon mirror that is the drive section and that deflects light from the semiconductor laser, and the motor board that is the polygon motor board on which a polygon motor that rotates the polygon mirror and a motor driver that rotationally drives the polygon motor are mounted, a laser unit to which one of a plurality of types of polygon motor boards can be mounted, and a photosensitive drum that is exposed by light deflected by the polygon mirror, the laser unit including either a first polygon motor board on which a first polygon motor and a first motor driver are mounted, or a second polygon motor board on which a second polygon motor and a second motor driver are mounted. and the controller has a three-state logic circuit capable of outputting from the output terminal one of a first control signal, a second control signal, and a third control signal, and in the laser unit, if the polygon motor board mounted is the first polygon motor board, when the first control signal or the second control signal is input, the first polygon motor is in a rotating state, and when the third control signal is input, the first polygon motor is in a stopped state, and if the polygon motor board mounted is the second polygon motor board, when the first control signal is input, the second polygon motor is in a rotating state, and when the second control signal or the third control signal is input, the second polygon motor is in a stopped state.

[0013] According to this, the polygon motor substrate of the mounted laser unit and the output terminal of the controller are connected by wiring. The controller can output one of the first to third control signals from the output terminal by controlling the three-state logic circuit. By outputting the first to third control signals, the controller can instruct the first and second polygon motors to start or stop rotation. Furthermore, when the controller outputs the second control signal, it can determine whether the polygon motor is in a rotating state or a stopped state, thereby determining the type of polygon motor substrate mounted.

[0014] The controller may also be configured to execute a first rotation determination process in which the controller outputs the first control signal from the output terminal to the mounted polygon motor board and determines whether the polygon motor of the mounted polygon motor board rotates; a second rotation determination process in which, after the first rotation determination process, the controller outputs the second control signal from the output terminal to the mounted polygon motor board and determines whether the polygon motor of the mounted polygon motor board rotates; and a motor board determination process in which, if the polygon motor of the mounted polygon motor board is rotating in the first rotation determination process and the second rotation determination process, the controller determines that the first polygon motor board is mounted relative to the laser unit; and, if the polygon motor of the mounted polygon motor board is rotating in the first rotation determination process and if the polygon motor of the mounted polygon motor board is not rotating in the second rotation determination process, the controller determines that the second polygon motor board is mounted relative to the laser unit.

[0015] According to this, if the polygon motor rotates in both the first and second rotation determination processes, the controller can determine that the mounted polygon motor substrate is the first polygon motor substrate. Also, if the polygon motor rotates in the first rotation determination process but does not rotate in the second rotation determination process, the controller can determine that the mounted polygon motor substrate is the second polygon motor substrate.

[0016] The controller may be configured to execute the first rotation determination process, the second rotation determination process, and the motor board determination process when the image forming apparatus is powered on.

[0017] According to this, when the image forming apparatus is powered on and started up, the controller executes the first and second rotation determination processes and the motor board determination process to determine the type of polygon motor board installed. If the laser unit is replaced and the type of polygon motor board is changed while the power is off, the type of polygon motor board can be determined when the power is turned on, and control parameters corresponding to the type of polygon motor can be set and used for control. The polygon motor can be controlled appropriately, improving the accuracy of image formation.

[0018] The controller may also be configured to determine that an error has occurred if it determines in the first rotation determination process that the polygon motor is not rotating, and to execute the second rotation determination process and the motor substrate determination process if it determines in the first rotation determination process that the polygon motor is rotating.

[0019] According to this, the controller executes the first rotation determination process before executing the second rotation determination process to determine whether the polygon motor will rotate in response to the first control signal. If the polygon motor does not rotate in response to the first control signal, the controller determines that an error has occurred. If the polygon motor does not rotate despite outputting the first control signal, which should result in a rotation state in both the first and second polygon motors, there is a high possibility that the polygon motor is malfunctioning. For this reason, by reporting an error without determining the type of polygon motor board, it is possible to prompt the user to replace the laser unit, for example.

[0020] The controller may also be configured to, after executing the motor substrate determination process, execute a preparatory process for forming an image using parameters according to the type of polygon motor of the polygon motor substrate determined by the motor substrate determination process.

[0021] According to this, by using parameters according to the type of polygon motor board, it is possible to rotate the polygon motor with high precision in the preparatory processing for forming an image, and the preparatory processing can be executed appropriately.

[0022] The controller may also be configured to store information about the polygon motor substrate determined in the motor substrate determination process in a volatile memory, maintain the memory of the polygon motor substrate information stored in the volatile memory while the image forming apparatus is powered on, and when the image forming apparatus is powered off and then on again, execute the first rotation judgment process, the second rotation judgment process, and the motor substrate determination process, and store the information about the polygon motor substrate determined in the motor substrate determination process in the volatile memory.

[0023] According to this, while the power of the image forming apparatus is on, parameters used for forming an image can be set based on information on the type of polygon motor board stored in the volatile memory. Also, when the power is turned off and then turned on again, the first and second rotation determination processes and the motor board determination process are executed to determine the type of polygon motor board installed at startup and store information on the determined type in the volatile memory. For example, if the laser unit is replaced while the power is off, the type of polygon motor board of the newly installed laser unit can be determined when the power is turned on.

[0024] The controller may also be configured to store information about the polygon motor substrate determined in the motor substrate determination process in a non-volatile memory, and when the image forming apparatus is powered on, execute a memory confirmation process to check whether information about the polygon motor substrate is stored in the non-volatile memory, and if the result of the memory confirmation process shows that information about the motor substrate is stored in the non-volatile memory, not execute the first rotation determination process, the second rotation determination process, and the motor substrate determination process, and if the result of the memory confirmation process shows that information about the polygon motor substrate is not stored in the non-volatile memory, execute the first rotation determination process, the second rotation determination process, and the motor substrate determination process.

[0025] This allows the information on the type of polygon motor substrate determined at the previous startup to be stored in nonvolatile memory, so that the stored information can be reused the next time the power is turned on, eliminating the need to execute the first and second rotation determination processes and the motor substrate determination process each time the power is turned on. Furthermore, if for some reason information is not stored in the non-volatile memory, the first and second rotation determination processes and the motor board determination process can be executed to determine the type of polygon motor board of the laser unit currently installed and store it in the non-volatile memory.

[0026] Furthermore, the first motor driver and the second motor driver may be capable of outputting a LOCKn signal to the controller, which indicates whether or not the polygon motor has rotated to a predetermined number of rotations, and the controller may be configured to receive the LOCKn signal from the motor driver of the mounted motor board, and determine whether or not the polygon motor of the mounted polygon motor board is rotating based on the LOCKn signal in the first rotation determination process and the second rotation determination process.

[0027] This allows the controller to determine whether the polygon motor is rotating or not based on the LOCKn signals input from the first and second motor drivers.

[0028] The mounted polygon motor board has a power supply unit and a pull-up resistor having one end connected to the wiring and the other end connected to the power supply unit, the mounted polygon motor board rotates the polygon motor when a signal higher than a predetermined voltage level is input from the output terminal, and stops the polygon motor when a signal lower than the predetermined voltage level is input from the output terminal, the first polygon motor board and the second polygon motor board each have a first pull-up resistor and a second pull-up resistor having different resistance values ​​as the pull-up resistor, and further comprises a main board on which the controller is mounted, the main board having a pull-up resistor having one end connected to the wiring and the other end connected to ground. and a pull-down resistor, and when the controller outputs a high-impedance signal as the second control signal from the output terminal, a voltage obtained by dividing the voltage generated by the power supply unit by the pull-up resistor and the pull-down resistor is input to the polygon motor board, and the resistance value of the pull-down resistor is set so that when the controller outputs the second control signal and the attached polygon motor board is the first polygon motor board, a signal greater than the predetermined voltage level is input from the output terminal, and when the controller outputs the second control signal and the attached polygon motor board is the second polygon motor board, a signal less than the predetermined voltage level is input from the output terminal.

[0029] According to this, when the controller outputs a high-impedance signal as a second control signal from the output terminal, a voltage generated by the power supply unit is divided by a pull-up resistor and a pull-down resistor, and the divided voltage is input to the polygon motor substrate. Each of the first and second polygon motor substrates has a first pull-up resistor and a second pull-up resistor, each having a different resistance value, as the pull-up resistor. The resistance value of the pull-down resistor is set so that when the mounted polygon motor substrate is the first polygon motor substrate, a signal higher than a predetermined voltage level is input from the output terminal, and when the mounted polygon motor substrate is the second polygon motor substrate, a signal lower than the predetermined voltage level is input from the output terminal. As a result, when the second control signal is output, the second control signal of different voltage levels is input to the first polygon motor substrate and the second polygon motor substrate. The second control signal can cause one of the first or second polygon motor to rotate and the other to stop. By checking the operation of the polygon motor when the second control signal is output, the type of polygon motor substrate can be determined.

[0030] The first polygon motor substrate may also be configured such that the first pull-up resistor is arranged outside the first motor driver, and the second polygon motor substrate may be configured such that the second pull-up resistor is arranged inside the second motor driver.

[0031] According to this, when the mounted polygon motor substrate is the first polygon motor substrate, the voltage generated by the power supply unit is divided by the first pull-up resistor and pull-down resistor outside the first motor driver, and the divided voltage is input to the first polygon motor substrate. Also, if the attached polygon motor substrate is the second polygon motor substrate, the voltage generated by the power supply unit is divided by the second pull-up resistor and pull-down resistor inside the second motor driver, and the divided voltage is input to the second polygon motor substrate. [Effects of the Invention]

[0032] According to the image forming apparatus of the present application, it is possible to determine the manufacturer and type of the motor board of the image forming apparatus while eliminating the dedicated wiring between the controller and the motor board. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a color laser printer according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing electrical connections between a main board and a laser unit according to the first embodiment. [Figure 3] FIG. 2 is a diagram showing the laser unit according to the first embodiment as viewed from above, illustrating the path of a beam emitted from a semiconductor laser until it reaches a BD sensor. [Figure 4] FIG. 10 is a diagram showing the connection configuration between the polygon motor terminals of the ASIC and the polygon motor board when the polygon motor board manufactured by company A is mounted. [Figure 5] FIG. 10 is a diagram showing the connection configuration between the polygon motor terminals of the ASIC and the polygon motor board when a polygon motor board manufactured by company B is mounted. [Figure 6] 10 is a flowchart of a determination process according to the first embodiment. [Figure 7] 10 is a flowchart of a determination process according to the second embodiment. [Figure 8] 10 is a flowchart of a determination process (motor determination process) according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0034] (First embodiment) A color laser printer according to a first embodiment, which is an embodiment of the image forming apparatus of the present application, will be described below with reference to FIG. 1. FIG. 1 is a cross-sectional view showing the schematic configuration of a color laser printer 10 according to the first embodiment. The color laser printer 10 is an example of the image forming apparatus of the present application. Hereinafter, the color laser printer 10 will be abbreviated to printer 10. The printer 10 includes a main body housing 2, a conveying unit 3, a processing unit 4, and a fixing device 5. For ease of explanation, the up-down direction and the front-rear direction of the printer 10 will be defined as indicated by the arrows in FIG. 1. The front side of the paper will be defined as the right, and the far side of the paper will be defined as the left.

[0035] The main body housing 2 has an openable front cover 11 and a rear cover 12, a supply tray 13, a discharge tray 15, and a transport path 17. The supply tray 13 is detachably attached to the bottom of the main body housing 2. Sheets S are placed on the supply tray 13. The sheets S are standard-sized paper such as A4 size. The sheets S are not limited to paper media such as plain paper or cardboard, and may be other recording media such as overhead projector film. The discharge tray 15 is provided at the top of the main body housing 2, and sheets S on which images have been formed are placed on the discharge tray 15.

[0036] The conveying unit 3 includes a pickup roller 21, a separation roller 22, and a plurality of conveying rollers 23. The pickup roller 21 picks up the sheets S in the supply tray 13 and conveys them toward the conveying path 17. The separation roller 22 separates the sheets S picked up by the pickup roller 21 one by one. The plurality of conveying rollers 23 eject the sheets S separated by the separation roller 22 along the conveying path 17, passing them through the process unit 4 and the fixing device 5 in this order, and onto the discharge tray 15. The conveying unit 3 rotates each roller based on the drive of a main motor (not shown) provided inside the main body housing 2.

[0037] The conveying unit 3 also includes a plurality of switchback rollers 25 that reverse the sheet S printed on one side, and a reverse conveying path 27. The printer 10 can switch the conveying destination of the sheet S between the discharge tray 15 and the reverse conveying path 27 indicated by the dashed line by swinging a flapper 28 provided downstream of the fixing device 5 on the conveying path 17. The conveying unit 3 swings the flapper 28 to the position indicated by the two-dot chain line based on the drive of the main motor, and rotates the plurality of switchback rollers 25, thereby conveying the sheet S upward along the reverse conveying path 27. The conveying unit 3 reversely rotates the switchback rollers 25 to convey the sheet S conveyed upward along the reverse conveying path 27, passing below the supply tray 13 and conveying it to the front side. As a result, the sheet S is reversed and conveyed to the base end of the conveying path 17. The printer 10 performs double-sided printing by printing on the top side of the reversed sheet S (the side opposite to the side printed the first time). Furthermore, the printer 10 is capable of printing even with the rear cover 12 open, and the printed sheet S can be discharged onto the open rear cover 12.

[0038] The process unit 4 has a function of forming an image on the sheet S, and transfers a toner image onto the sheet S. The process unit 4 includes a laser unit 31, a drum unit 32, four developing cartridges 33Y, 33M, 33C, and 33K, and a transfer unit 34.

[0039] The laser unit 31 is disposed in the upper part of the main body housing 2, and exposes the surface of the photosensitive drum 41 by emitting laser light indicated by the dashed line onto the surface of the photosensitive drum 41 of the drum unit 32. Details of the laser unit 31 will be described later.

[0040] The drum unit 32 is disposed between the supply tray 13 and the laser unit 31 inside the main body housing 2, and includes four photosensitive drums 41, four chargers 43, and a support frame 45 that supports the photosensitive drums 41, etc. The drum unit 32 is detachable from the main body housing 2 when the front cover 11 is open.

[0041] The developer cartridges 33Y, 33M, 33C, and 33K correspond to four colors: yellow (Y), magenta (M), cyan (C), and black (K), respectively, and are detachably mounted in the drum unit 32 in that order from the front to the rear of the printer 10. Each of the developer cartridges 33Y, 33M, 33C, and 33K includes a developer roller 51, a supply roller 52, and a toner storage section 53. Note that the four developer cartridges 33Y, 33M, 33C, and 33K differ in toner color but are otherwise identical in configuration. For this reason, in the following description, the four developer cartridges 33Y, 33M, 33C, and 33K corresponding to each color will be collectively referred to as developer cartridges 33. In addition, other devices (such as semiconductor laser 77) corresponding to the colors yellow, magenta, cyan, and black may be described individually with the letters Y, M, C, and K added after their reference numbers, or collectively without reference numbers, just like the developing cartridge 33.

[0042] The transfer unit 34 is disposed between the supply tray 13 and the drum unit 32 inside the main body housing 2, and includes a drive roller 61, a driven roller 62, a conveyor belt 63, and four transfer rollers 64. The conveyor belt 63 is stretched between the drive roller 61 and the driven roller 62, and its upper surface is in contact with the photosensitive drum 41. The four transfer rollers 64 are disposed inside the conveyor belt 63 so as to sandwich the conveyor belt 63 between themselves and the corresponding photosensitive drum 41.

[0043] The charger 43 is provided above the photosensitive drum 41 and is, for example, a scorotron charger having a charging wire or grid. The process unit 4 generates a corona discharge using the charger 43, uniformly positively charging the surface of the photosensitive drum 41. The laser unit 31 irradiates the surface of the photosensitive drum 41 with laser light to expose it, thereby forming an electrostatic latent image based on image data on the surface of the photosensitive drum 41. Note that the device that charges the photosensitive drum 41 is not limited to a scorotron charger, and may be another device such as a roller-type charging roller. Furthermore, the polarity with which the photosensitive drum 41 is charged is not limited to positive charging, and may be negative charging.

[0044] Furthermore, the process unit 4 supplies toner in the toner storage unit 53 to the supply roller 52, which then supplies the toner to the development roller 51. The toner supplied to the development roller 51 is carried on the development roller 51 as the development roller 51 rotates. The development roller 51 is rotated by the rotational driving force of the main motor, supplies toner to the photosensitive drum 41, develops the electrostatic latent image formed on the surface of the photosensitive drum 41, and carries a toner image. The toner carried on the development roller 51 moves to the electrostatic latent image on the photosensitive drum 41 due to the potential difference between the development roller 51 and the electrostatic latent image formed on the photosensitive drum 41, and forms a toner image. This toner image is transferred to the sheet S by applying a negative voltage to the transfer roller 64 while the photosensitive drum 41 is in contact with the sheet S on the transport path 17.

[0045] The fixing device 5 is disposed behind the process unit 4 within the main body housing 2. The sheet S onto which the toner image has been transferred is transported to the fixing device 5. The fixing device 5 has a heating roller 67 that heats the sheet S and a pressure unit 68 that sandwiches the sheet S between the heating roller 67 and the sheet S. The heating roller 67 has a heater 69 therein that heats the heating roller 67. The pressure unit 68 has an endless belt, a pressure pad that sandwiches the endless belt between the heating roller 67 and the pressure pad, a holder that supports the pressure pad, a belt guide, etc. The pressure unit 68 is rotated by the rotational driving force transmitted from the main motor, and presses the sheet S against the heating roller 67 to apply pressure to the sheet S. In this way, the fixing device 5 fixes the toner image to the sheet S.

[0046] (Regarding laser unit 31) Next, the laser unit 31 will be described. As shown in FIG. 2, the printer 10 is equipped with a main board 71 that controls the laser unit 31. The main board 71 has an ASIC 72. The ASIC 72 is an Application Specific Integrated Circuit and includes a CPU and the like. The ASIC 72 reads and executes a control program from a storage device (such as a non-volatile memory 76 described below) and performs overall control of the printer 10. Note that the configuration of the main board 71 shown in FIG. 2 is one example. For example, the main board 71 may be equipped with an SoC (System on a Chip) as a controller instead of an ASIC.

[0047] The main board 71 is connected to the laser unit 31 via a harness 73. The harness 73 is, for example, a flexible flat cable. The main board 71 controls the operation of the laser unit 31 via the harness 73.

[0048] The laser unit 31 also has an LD substrate 75, four semiconductor lasers 77Y, 77M, 77C, and 77K corresponding to the respective colors, and a polygon motor substrate 78. The LD substrate 75 has four LD drivers 79Y, 79M, 79C, and 79K corresponding to the respective colors, four generation circuits 81Y, 81M, 81C, and 81K corresponding to the respective colors, a first BD sensor 83, and a second BD sensor 84.

[0049] The LD driver 79, semiconductor laser 77, and generation circuit 81 corresponding to each color have the same configuration. Therefore, in the following description, they will be referred to as the LD driver 79, semiconductor laser 77, and generation circuit 81. As shown in FIG. 2, the semiconductor laser 77 has a first laser diode LD1, a second laser diode LD2, and a photodiode PD. Note that FIG. 2 illustrates the first laser diode LD1 and the like only for the semiconductor laser 77K corresponding to black. The semiconductor laser 77 is, for example, a unitized unit in which the first and second laser diodes LD1 and LD2 and the photodiode PD are housed in a cap and electrically connected to the LD substrate 75. The first and second laser diodes LD1 and LD2 are, for example, edge-emitting elements that emit laser light from two end faces of the element. The first laser diode LD1 of the semiconductor laser 77 emits laser light L from the end face facing the polygon mirror 92 (the upper end face in FIG. 3) and emits back laser light (not shown) from the opposite end face. The second laser diode LD2 has the same configuration as the first laser diode LD1. The photodiode PD is attached in a position within the unit where it can receive the back laser light from both the first and second laser diodes LD1 and LD2.

[0050] The first and second laser diodes LD1 and LD2 are examples of the semiconductor laser of the present application. The semiconductor laser of the present application is not limited to an edge-emitting element, but may be a surface-emitting element. Furthermore, the element that receives laser light such as back laser light is not limited to a photodiode, but may be another light-receiving element that can convert light into an electrical signal, such as a CMOS image sensor.

[0051] The LD driver 79 is a driver circuit that causes the semiconductor laser 77 to emit light, and includes, for example, a light intensity control circuit (APC), a modulation circuit, and a current mirror circuit corresponding to each of the first and second laser diodes LD1 and LD2. Therefore, in the following description, the first laser diode LD1 will be mainly described, and the description of the second laser diode LD2 will be omitted as appropriate.

[0052] When the first laser diode LD1 emits light and receives the back laser light, the photodiode PD generates a photocurrent Ipd corresponding to the amount of received back laser light. The LD driver 79 detects a detection voltage corresponding to the magnitude of the photocurrent Ipd using a current mirror circuit, compares the detection voltage detected by the current mirror circuit with a reference voltage Vref1 input from the generation circuit 81 using a light amount adjustment circuit, and controls the current Ild1 flowing through the first laser diode LD1 so that the voltage value of the detection voltage becomes the reference voltage Vref1. As a result, the current Ild1 is adjusted based on the reference voltage Vref1 and the detection voltage, and the light emission amount of the first laser diode LD1 is adjusted.

[0053] The generation circuit 81 includes, for example, a linear regulator, a transistor, a voltage dividing resistor, and a smoothing circuit, and generates reference voltages Vref1 and Vref2 based on the voltage input from the power circuit of the main board 71. The ASIC 72 also outputs PWM signals (pulse width modulation signals) PWM1 and PWM2 to the generation circuit 81 via the harness 73. The generation circuit 81 turns on and off a transistor based on the duty ratio of the PWM signal PWM1 to change the reference voltage Vref1. This allows the ASIC 72 to change the duty ratio of the PWM signal PWM1 to change the voltage value of the reference voltage Vref1 and control the light emission intensity of the first laser diode LD1. Similarly, the ASIC 72 controls the light emission intensity of the second laser diode LD2 using the PWM signal PWM2.

[0054] The light intensity adjustment circuit of the LD driver 79 is connected to the anode of the first laser diode LD1 via a modulation circuit. This modulation circuit turns the light emission of the first laser diode LD1 on and off by turning on and off the current Ild1 based on the binary video signal VS1 input from the ASIC 72. As a result, the LD driver 79 switches the first and second laser diodes LD1 and LD2 between an on-state and an off-state based on the video signals VS1 and VS2 input from the ASIC 72.

[0055] For example, during printing, the ASIC 72 changes the video signals VS1 and VS2 based on image data and turns on and off the first and second laser diodes LD1 and LD2 to form an electrostatic latent image on the photosensitive drum 41. The printer 10 of this embodiment can simultaneously perform exposure using two laser diodes. Specifically, the first and second laser diodes LD1 and LD2 are, for example, arranged at offset positions. As shown in FIG. 3 , the laser beams L of the first and second laser diodes LD1 and LD2 are reflected by the respective reflective surfaces of the polygon mirror 92 at offset positions in the direction of the rotation axis of the polygon mirror 92 (first direction, described below). Therefore, by rotating at high speed, the polygon mirror 92 periodically deflects the laser beams L emitted from the first and second laser diodes LD1 and LD2, thereby simultaneously forming two scanning lines on the surface of the photosensitive drum 41 in a direction perpendicular to the rotation direction of the photosensitive drum 41, i.e., parallel to the main scanning direction. The laser unit 31 may be configured to include only one laser diode, or may be configured to include three or more laser diodes.

[0056] Furthermore, the ASIC 72 is connected to each of the four LD drivers 79 via a harness 73, and outputs an enable signal ENABLE to each LD driver 79. This enable signal ENABLE is a control signal that switches between a state in which the LD driver 79 is driven and a state in which the LD driver 79 is stopped. In this embodiment, the wiring that outputs the enable signal ENABLE to the four LD drivers 79 is shared, thereby reducing the number of wirings. Note that the wiring that outputs the enable signal ENABLE to the four LD drivers 79Y, 79M, 79C, and 79K may be separate wirings.

[0057] The polygon motor board 78 also has a motor driver 87 and a polygon motor 89. The polygon motor board 78 is connected to the main board 71 via a harness 73. The harness 73 connecting the LD board 75 and the main board 71 may be a harness separate from the harness 73 connecting the polygon motor board 78 and the main board 71.

[0058] The main board 71 also has three polygon motor terminals 102, 103, and 104 as terminals for connection to the motor driver 87. The motor driver 87 also has an ON signal terminal 121 to which an ON signal ON is input, a motor clock signal terminal 122 to which a motor clock signal CLK is input, and a LOCKn signal terminal 123 that outputs a LOCKn signal LOCKn.

[0059] The ON signal terminal 121 is connected to the polygon motor terminal 102 via a wire 125 included in the harness 73, and an ON signal ON is input thereto. The ASIC 72 can output, as the ON signal ON, a Start signal that instructs the motor driver 87 to start rotational driving, or a Stop signal that instructs the motor driver 87 to stop rotational driving. The Start signal is, for example, a High-level signal that is higher than a predetermined voltage level (threshold), and the Stop signal is a Low-level signal that is equal to or lower than the predetermined voltage level.

[0060] The motor clock signal terminal 122 is connected to the polygon motor terminal 103 via a wiring 126 included in the harness 73, and receives the motor clock signal CLK. The polygon motor 89 is, for example, a DC brushless motor. The motor driver 87 supplies, for example, a 24V DC current supplied from the main board 71 to the windings of the polygon motor 89. The motor driver 87 has multiple switch elements that switch the current supplied to the windings of the polygon motor 89. The motor clock signal CLK is a control signal for switching the switch elements of the motor driver 87 on and off. When an ON signal ON indicating a Start signal is input, the motor driver 87 drives each circuit and enters a state (rotation state) in which the switch elements are controlled to be turned on and off based on the motor clock signal CLK. This causes the polygon motor 89 to start rotating. The ASIC 72 can control the rotation speed, etc. of the polygon motor 89 by changing the frequency, etc., of the motor clock signal CLK. When an ON signal indicating a Stop signal is input, the motor driver 87 stops each circuit and enters a stop state in which the rotation of the polygon motor 89 is stopped.

[0061] Furthermore, the LOCKn signal terminal 123 is connected to the polygon motor terminal 104 via a wire 127 included in the harness 73 and outputs a LOCKn signal LOCKn. The LOCKn signal LOCKn is a signal indicating whether the polygon motor 89 has rotated to a predetermined number of rotations (a predetermined number of rotations or rotation speed). For example, the motor driver 87 outputs a high-level LOCKn signal LOCKn from the LOCKn signal terminal 123 until the number of rotations per unit time of the polygon motor 89 reaches a predetermined number of rotations, and when it detects that the number of rotations per unit time has reached the predetermined number of rotations, it outputs a low-level LOCKn signal LOCKn from the LOCKn signal terminal 123. This allows the ASIC 72 to detect whether the polygon motor 89 has rotated to the predetermined number of rotations based on the LOCKn signal LOCKn. For example, the ASIC 72 waits a predetermined waiting time after the low-level LOCKn signal LOCKn is input to the polygon motor terminal 104, and then allows image formation. That is, after the predetermined waiting time has elapsed, the rotation speed of the polygon motor 89 increases to the rotation speed required to form an image, and it is determined that the rotation speed is stable. Note that the predetermined rotations in the present disclosure are not limited to the number of rotations per unit time, but may also refer to a state in which the rotation speed of the motor reaches a predetermined rotation speed.

[0062] 3 is a diagram of the laser unit 31 viewed from above, showing the path of the beam LB emitted from the semiconductor laser 77 until it reaches the first and second BD sensors 83 and 84. As shown in FIG. 3, the laser unit 31 has four collimating lenses (which may also be called coupling lenses) 91Y, 91M, 91C, and 91K, a polygon mirror 92, two fθ lenses (which may also be called scanning lenses) 93YM and 93CK, four reflecting mirrors 94Y, 94M, 94C, and 94K corresponding to each color, a first mirror 95, a second mirror 96, and a frame 97. The collimating lens 91 and other components are attached to the frame 97. In the following description, a direction parallel to the rotation axis X1 of the polygon mirror 92 (a direction perpendicular to the plane of FIG. 3) is referred to as a "first direction." Furthermore, the direction perpendicular to the first direction, in which the polygon mirror 92 and the fθ lenses 93YM and 93CK are aligned (the left-right direction in FIG. 3), is referred to as the "second direction." Furthermore, the direction perpendicular to the first and second directions is referred to as the "third direction." The third direction corresponds to the main scanning direction, and the first direction corresponds to the sub-scanning direction. Arrows indicating each direction in the drawings point to one side in each direction.

[0063] The LD substrate 75 is attached to a side surface of the frame 97 in the third direction. The four semiconductor lasers 77 are attached to the center of the LD substrate 75 in the first and second directions. Each of the four collimating lenses 91 is disposed facing a corresponding semiconductor laser 77 corresponding to each color in the third direction. The polygon mirror 92, collimating lens 91, and semiconductor laser 77 are disposed side by side along the third direction. The collimating lens 91 converts laser light L from the semiconductor laser 77 into a beam LB and emits the beam LB toward the polygon mirror 92. In the following description, to avoid complication, the beam LB may be referred to as laser light L. For example, the laser light L emitted from the semiconductor laser 77 toward the polygon mirror 92 refers to the beam LB emitted from the semiconductor laser 77, converted by the collimating lens 91, and emitted toward the polygon mirror 92. The above-described optical system configuration is merely an example. The laser unit 31 may include an aperture plate and a focusing lens through which the laser light L passes.

[0064] The laser unit 31 converts the laser light L emitted from the semiconductor laser 77 into a beam LB, and the beam LB deflected by a polygon mirror 92 is directed toward and exposes the photosensitive drum 41 of the developer cartridge 33. The polygon mirror 92 is a rotating polygonal mirror, and is shaped, for example, like a regular pentagonal prism, with five reflective surfaces constituting each side of the pentagonal prism. The polygon mirror 92 is driven to rotate by a polygon motor 89 (see FIG. 2) and deflects the laser light L from the semiconductor laser 77. The polygon mirror 92 rotates, for example, clockwise in FIG. 3, and deflects the beam LB incident from the collimator lens 91 in the main scanning direction.

[0065] The fθ lens 93 focuses the beam LB reflected by the polygon mirror 92. The reflecting mirrors 94 are provided corresponding to each color and are arranged side by side in the second direction. The four reflecting mirrors 94 are arranged side by side in the order of 94Y, 94M, 94C, and 94K from one side in the second direction (the right side in FIG. 3). The polygon mirror 92 is arranged between the reflecting mirrors 94C and 94M in the second direction. The fθ lens 93YM is shared by the beams LB of the semiconductor lasers 77Y and 77M and is arranged between the reflecting mirror 94M and the polygon mirror 92 in the second direction. The fθ lens 93CK is shared by the beams LB of the semiconductor lasers 77C and 77K and is arranged between the reflecting mirror 94C and the polygon mirror 92 in the second direction.

[0066] The four reflecting mirrors 94 are attached, for example, at different positions and in different orientations in the first direction, and focus the beams LB emitted from the four semiconductor lasers 77 and focused by the fθ lenses 93 onto the surfaces of the photosensitive drums 41 of the respective colors. Therefore, the optical distances (optical paths) of the beams LB corresponding to the respective colors from the semiconductor lasers 77 to the photosensitive drums 41 are different. When the polygon mirror 92 rotates in conjunction with the rotation of the polygon motor 89, the angle of the reflecting surface relative to the emission direction of the beam LB from the collimator lens 91 periodically changes. As a result, the beams LB are periodically deflected by the reflecting surface of the polygon mirror 92, forming scan lines on the surface of the photosensitive drums 41.

[0067] The first BD sensor 83 and the second BD sensor 84 are disposed at positions that are opposite ends of the LD substrate 75 in the second direction. The first BD sensor 83 is a sensor that detects the beam LBY corresponding to yellow out of the beams LB deflected by the polygon mirror 92. When the reflecting surface of the polygon mirror 92 is at a specific angle, the first mirror 95 reflects the beam LBY, which is irradiated from the polygon mirror 92 via the fθ lens 93YM, toward the first BD sensor 83. Note that the first effective scanning range RA1 shown in FIG. 3 indicates the scanning range used for forming an image of the beam LBY corresponding to yellow, and the second effective scanning range RA2 indicates the scanning range used for forming an image of the beam LBK corresponding to black.

[0068] The first BD sensor 83 includes, for example, a photodiode and a comparison circuit, and outputs a high-level detection signal Vo1 (see FIG. 2) when the amount of light of the beam LBY received by the photodiode is equal to or less than a predetermined threshold, and outputs a low-level detection signal Vo1 when the amount of light is greater than the predetermined threshold. The first BD sensor 83 outputs the detection signal Vo1 to the ASIC 72 on the main board 71 via the harness 73. The ASIC 72 detects a predetermined timing after writing of the beam LBY to the photosensitive drum 41 corresponding to yellow is completed based on the detection signal Vo1 of the first BD sensor 83.

[0069] The second BD sensor 84 and the second mirror 96 have the same configuration as the first BD sensor 83 and the first mirror 95, and therefore detailed description thereof will be omitted. Like the first BD sensor 83, the second BD sensor 84 receives the beam LBK, which is irradiated from the polygon mirror 92 via the fθ lens 93CK and reflected by the second mirror 96 when the reflective surface of the polygon mirror 92 is at a specific angle. The second BD sensor 84 outputs a detection signal Vo2 corresponding to the amount of received beam LBK to the ASIC 72. For example, the ASIC 72 changes the video signals VS1 and VS2 output to the LD drivers 79 of each color based on the time when the second BD sensor 84 detects the beam LBK, thereby controlling the timing at which the LD substrate 75 starts exposing the photosensitive drum 41. The ASIC 72 may also perform correction for thermal expansion of the laser unit 31 (such as the frame 97 and lens) based on the detection signals Vo1 and Vo2 of the first and second BD sensors 83 and 84.

[0070] 2, the main board 71 is mounted with a volatile memory 74 and a nonvolatile memory 76. The volatile memory 74 is, for example, a RAM (Random Access Memory). The nonvolatile memory 76 is, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory). Note that the nonvolatile memory 76 is not limited to an EEPROM, and may be other nonvolatile memories such as a flash memory or an EPROM.

[0071] The volatile memory 74 and the nonvolatile memory 76 are used to store information about the manufacturer of the motor driver 87. The nonvolatile memory 76 also stores, for example, control parameters for each manufacturer of the motor driver 87. Specifically, the nonvolatile memory 76 stores, for each manufacturer, information about the waiting time from when a low-level LOCKn signal LOCKn is input until the polygon motor 89 rotates to a predetermined number of revolutions, as the LOCKn signal LOCKn. The control parameter for each manufacturer is not limited to the above-described waiting time information, and may also be information about the motor clock signal CLK for each manufacturer. Alternatively, the control parameter may be a value indicating the magnitude of the current or voltage supplied from the motor driver 87 to the polygon motor 89, or a value indicating the rotational speed at which the polygon motor 89 rotates.

[0072] (Connection between the polygon motor terminal 102 of the ASIC 72 and the polygon motor board 78) 4 and 5 show the connection configuration between the polygon motor terminal 102 of the ASIC 72 and the polygon motor board 78. Here, the polygon motor board 78 to be mounted is determined from polygon motor boards 78 made by different manufacturers, and the determined polygon motor board 78 is mounted in the printer 10. The ASIC 72 needs to set control parameters corresponding to the polygon motor 89 of the mounted polygon motor board 78 from among the control parameters stored in the nonvolatile memory 76. For this reason, the ASIC 72 needs to determine the manufacturer of the polygon motor board 78.

[0073] On the other hand, if a dedicated wiring for determining the manufacturer of the polygon motor board 78 were provided between the ASIC 72 and the polygon motor board 78, the number of wiring lines would increase, raising the issue of how to route the wiring. In the printer 10 of this embodiment, the ASIC 72 determines the manufacturer of the motor driver 87 using the wiring 125 that transmits the ON signal ON. That is, the wiring used for control during image formation processing is also used as the wiring for determining the manufacturer of the polygon motor board 78. In the following explanation, as an example, a case where the polygon motor board 78 manufactured by Company A shown in FIG. 4 is mounted on the printer 10 will be compared with a case where the polygon motor board 78 manufactured by Company B shown in FIG. 5 is mounted on the printer 10. The polygon motor board 78 and motor driver 87 manufactured by Company A will be referred to as the first polygon motor board 78A and the first motor driver 87A. The polygon motor board 78 and motor driver 87 manufactured by Company B will be referred to as the second polygon motor board 78B and the second motor driver 87B.

[0074] As shown in FIGS. 4 and 5, the ASIC 72 includes a tri-state logic circuit 131 connected to the polygon motor terminal 102, which outputs an ON signal ON. The tri-state logic circuit 131 is a circuit capable of outputting one of a first control signal CL1, a second control signal CL2, and a third control signal CL3 from the polygon motor terminal 102. The tri-state logic circuit 131 includes a first switch element SW1 and a second switch element SW2. Based on the control of the ASIC 72, the first switch element SW1 switches between a state in which the connection part 133 is connected to the second power supply Vcc2 and a state in which the connection part 133 is connected to ground GND. Based on the control of the ASIC 72, the second switch element SW2 switches between a connection state in which the connection part 133 is connected to the polygon motor terminal 102 and a disconnection state in which the connection part 133 is disconnected from the polygon motor terminal 102. The main board 71 also includes a pull-down resistor Rdown. The pull-down resistor Rdown has one end connected to the wiring 125 and the other end connected to the ground GND.

[0075] 4, the first polygon motor substrate 78A has a first pull-up resistor Rup1. The first pull-up resistor Rup1 is mounted on the first polygon motor substrate 78A and is provided outside the first motor driver 87A. One end of the first pull-up resistor Rup1 is connected to the wiring 125, and the other end is connected to a first power supply unit Vcc1. The first power supply unit Vcc1 supplies, for example, a power supply voltage Vcc (e.g., 3.3 V) that has the same potential as the second power supply unit Vcc2.

[0076] As shown in FIG. 5, the second motor driver 87B of the second polygon motor substrate 78B has a second pull-up resistor Rup2. Therefore, the second pull-up resistor Rup2 is mounted inside the first motor driver 87A. One end of the second pull-up resistor Rup2 is connected to the wiring 125 via the ON signal terminal 121 of the second motor driver 87B, and the other end is connected to the first power supply Vcc1. The circuit configurations shown in FIGS. 4 and 5 are merely examples. For example, the first pull-up resistor Rup1 may be provided inside the first motor driver 87A of the first polygon motor substrate 78A. Alternatively, the second pull-up resistor Rup2 may be provided outside the second motor driver 87B.

[0077] 4 and 5 show, from top to bottom, the first state, the second state, and the third state. The first control signal CL1, the second control signal CL2, and the third control signal CL3 are control signals output from the polygon motor terminal 102 in the first state, the second state, and the third state, respectively.

[0078] In the first state shown in the upper diagrams of Figures 4 and 5, the ASIC 72 connects the first switch element SW1 to the second power supply Vcc2 and puts the second switch element SW2 in a connected state. The potential of the polygon motor terminal 102 becomes the power supply voltage Vcc. The potential of the ON signal terminal 121 also becomes the power supply voltage Vcc. In both Company A and Company B, the ASIC 72 outputs a High-level ON signal ON, which is higher than a predetermined voltage level (threshold), as the first control signal CL1 to each of the first and second polygon motor boards 78A and 78B.

[0079] When the first and second motor drivers 87A and 87B receive an input voltage Vin greater than a predetermined voltage level (e.g., 1.5 V), they determine that a Start signal instructing the start of rotational driving has been input, and they rotate the polygon motor 89. Furthermore, when the first and second motor drivers 87A and 87B receive an input voltage Vin equal to or less than the predetermined voltage level, they determine that a Stop signal instructing the start of rotational driving has been input, and they stop the rotation of the polygon motor 89. The voltage value of the power supply voltage Vcc is greater than the predetermined voltage level. Therefore, when the tri-state logic circuit 131 is in the first state, the first and second motor drivers 87A and 87B receive an input voltage Vin greater than the predetermined voltage level, and execute control to start the rotational driving of the polygon motor 89.

[0080] In the third state shown in the lower diagrams of FIGS. 4 and 5, the ASIC 72 connects the first switch element SW1 to ground GND and keeps the second switch element SW2 connected. The potential of the polygon motor terminal 102 becomes the reference potential of ground GND. A current Ir flows from the first power supply Vcc1 through the first pull-up resistor Rup1 (or second pull-up resistor Rup2) and the wiring 125 to ground GND. In both companies, the ASIC 72 outputs a low-level ON signal ON below a predetermined voltage level as the third control signal CL3 to each of the first and second polygon motor substrates 78A and 78B. The input voltage Vin input from the ON signal terminal 121 to the first and second motor drivers 87A and 87B becomes below a predetermined voltage level (e.g., 0 V), which is a threshold. Therefore, since the input voltage Vin is equal to or lower than the predetermined voltage level, the first and second motor drivers 87A and 87B determine that a Stop signal has been input and stop the rotation of the polygon motor 89. For example, when starting the image formation process, the ASIC 72 outputs a first control signal CL1 and a motor clock signal CLK to rotate the polygon motor 89. When completing the image formation process and stopping the polygon motor 89, the ASIC 72 outputs a third control signal CL3 to instruct the first and second motor drivers 87A and 87B to stop the rotation and stops the output of the motor clock signal CLK.

[0081] 4 and 5, the ASIC 72 connects the first switch element SW1 to ground GND and disconnects the second switch element SW2. The ASIC 72 disconnects the connection between the connection unit 133 and the polygon motor terminal 102, thereby outputting a high-impedance (Hi-Z) signal from the polygon motor terminal 102 as the second control signal CL2. When the second switch element SW2 is disconnected, a current Ir flows from the first power supply unit Vcc1 to ground GND via the first pull-up resistor Rup1 (or the second pull-up resistor Rup2), the wiring 125, and the pull-down resistor Rdown. The value of the input voltage Vin input to the ON signal terminal 121 of the motor driver 87 is given by the following equation. (In the case of Figure 4) Vin = Vcc * Rdown / (Rup1 + Rdown) (In the case of Figure 5) Vin = Vcc * Rdown / (Rup2 + Rdown)

[0082] In the case of company A shown in Fig. 4, when the ASIC 72 outputs the second control signal CL2, the first motor driver 87A receives an input voltage Vin obtained by dividing the power supply voltage Vcc of the first power supply unit Vcc1 by a first pull-up resistor Rup1 and a pull-down resistor Rdown. Also, in the case of company B shown in Fig. 5, the second motor driver 87B receives an input voltage Vin obtained by dividing the power supply voltage Vcc of the first power supply unit Vcc1 by a second pull-up resistor Rup2 and a pull-down resistor Rdown as the second control signal CL2.

[0083] Therefore, the input voltage Vin is determined by the power supply voltage Vcc and the resistance value of each resistor. The resistance values ​​of the first pull-up resistor Rup1 and the second pull-up resistor Rup2 are determined, for example, by the manufacturer of the polygon motor board 78. The resistance value of the pull-down resistor Rdown is adjusted so that the signal level of the second control signal CL2 is greater than a predetermined voltage level (threshold) for one of Company A and Company B, and the signal level is equal to or less than the predetermined voltage level for the other. Note that a variable resistor may be connected as the pull-down resistor Rdown, and the resistance value may be adjusted after the printer 10 is manufactured.

[0084] In this embodiment, the resistance value of the first pull-up resistor Rup1 is smaller than that of the second pull-up resistor Rup2. For example, the resistance value of the first pull-up resistor Rup1 is approximately 5 kΩ, and the resistance value of the second pull-up resistor Rup2 is approximately 50 kΩ. The resistance value of the pull-down resistor Rdown is set so that when the pull-up resistor is the first pull-up resistor Rup1 (when the mounted polygon motor board 78 is the first polygon motor board 78A manufactured by company A), an input voltage Vin greater than a predetermined voltage level is input to the first motor driver 87A. The resistance value of the pull-down resistor Rdown is set so that when the pull-up resistor is the second pull-up resistor Rup2 (when the mounted polygon motor board 78 is the second polygon motor board 78B manufactured by company B), an input voltage Vin equal to or less than a predetermined voltage level is input to the second motor driver 87B.

[0085] By connecting the pull-down resistor Rdown having the above resistance value between the wiring 125 and ground GND, in the second state of the manufacturer A shown in the middle diagram of FIG. 4, a high-level input voltage Vin is input to the first polygon motor substrate 78A, which controls the polygon motor 89 to start rotating. On the other hand, in the second state of the manufacturer B shown in the middle diagram of FIG. 5, a low-level input voltage Vin is input to the second polygon motor substrate 78B, which stops the polygon motor 89 from rotating. By setting the resistance value of the pull-down resistor Rdown in this way, the operating state of the first polygon motor substrate 78A manufactured by manufacturer A and the operating state of the second polygon motor substrate 78B manufactured by manufacturer B in the second state can be made different. The ASIC 72 determines the manufacturer of the polygon motor substrate 78 based on the difference in the operating state of the second state.

[0086] (Regarding the process for determining the manufacturer of the motor driver 87) Next, the determination process by the ASIC 72 to determine the manufacturer of the motor driver 87 will be described with reference to Fig. 6. Fig. 6 shows a flowchart of the determination process. The ASIC 72 starts the process of Fig. 6 when the printer 10 is turned on. Note that the condition for starting the process of Fig. 6 is not limited to the condition that the power is turned on, but may also be the condition that the laser unit 31 is replaced, for example.

[0087] 6, the ASIC 72 outputs a third control signal CL3 in step (hereinafter simply referred to as S) 1. For example, when the power of the printer 10 is turned off, the ASIC 72 transitions the tri-state logic circuit 131 to the third state. Therefore, in the initial state when the power of the printer 10 is turned on, the tri-state logic circuit 131 is in the third state, and the third control signal CL3 is output from the polygon motor terminal 102. Because a Stop signal is input to both the first and second motor drivers 87A and 87B, the polygon motor 89 does not rotate.

[0088] Next, in S2, the ASIC 72 transitions the tri-state logic circuit 131 to the first state and outputs a first control signal CL1 from the polygon motor terminal 102. The ASIC 72 also outputs a motor clock signal CLK of a predetermined frequency from the polygon motor terminal 103. When the Start signal and the motor clock signal CLK are input to both the first and second motor drivers 87A and 87B, the polygon motor 89 is rotated.

[0089] Next, the ASIC 72 executes a first rotation determination process to determine whether the polygon motor 89 has rotated (S3). For example, if a low-level LOCKn signal LOCKn is input to the polygon motor terminal 104 within a predetermined time after starting to output the first control signal CL1 in S2, the ASIC 72 determines that the polygon motor 89 has rotated (S3: YES) and executes S5. On the other hand, if a low-level LOCKn signal LOCKn is not input within a predetermined time after starting to output the first control signal CL1 in S2, the ASIC 72 determines that the polygon motor 89 is not rotating (S3: NO) and executes S6. Note that the method of determining whether the polygon motor 89 has rotated is not limited to the method using the LOCKn signal LOCKn, and a method using an encoder or a sensor may also be used.

[0090] If a low-level LOCKn signal LOCKn is not input, there is a possibility that some kind of failure or error has occurred in the polygon motor board 78 or the polygon motor 89. Therefore, in S6, the ASIC 72 executes processing to notify the user of the error and executes processing to stop the polygon motor 89. The ASIC 72 displays, for example, on a touch panel (not shown) of the printer 10, that an error has occurred. The ASIC 72 also transitions the tri-state logic circuit 131 to the third state, outputs a third control signal CL3, stops the polygon motor 89, and stops the output of the motor clock signal CLK. The ASIC 72 then ends the processing shown in FIG. 6.

[0091] In addition, in S5, the ASIC 72 stops the polygon motor 89. The ASIC 72 transitions the tri-state logic circuit 131 to the third state, outputs the third control signal CL3, stops the polygon motor 89, and stops the output of the motor clock signal CLK. Next, in S7, the ASIC 72 transitions the tri-state logic circuit 131 to the second state and outputs a second control signal CL2 from the polygon motor terminal 102. The ASIC 72 also outputs a motor clock signal CLK of a predetermined frequency from the polygon motor terminal 103. The ASIC 72 may continue outputting the motor clock signal CLK up to S7 without stopping the output of the motor clock signal CLK in S5. As shown in FIG. 4, if the motor driver 87 is a first motor driver 87A manufactured by company A, a Start signal is output as the second control signal CL2, and the polygon motor 89 rotates. On the other hand, as shown in FIG. 5, if the motor driver 87 is a second motor driver 87B manufactured by company B, a Stop signal is output as the second control signal CL2, and the polygon motor 89 does not rotate.

[0092] After executing S7, the ASIC 72 executes a second rotation determination process to determine whether the polygon motor 89 is rotating (S8). As in S3, if a Low-level LOCKn signal LOCKn is input before a predetermined time has elapsed since the ASIC 72 started outputting the second control signal CL2 in S7, the ASIC 72 determines that the polygon motor 89 is rotating (S8: YES). The ASIC 72 stores information indicating that a laser unit 31 equipped with a first polygon motor board 78A manufactured by Company A is installed in the volatile memory 74 (S9, an example of the motor board determination process of the present application). After executing S9, the ASIC 72 executes S10.

[0093] On the other hand, if a Low-level LOCKn signal LOCKn is not input even after a predetermined time has elapsed, the ASIC 72 determines that the polygon motor 89 is not rotating (S8: NO). The ASIC 72 stores information indicating that the laser unit 31 on which the second polygon motor board 78B manufactured by company B is mounted in the volatile memory 74 (S11, an example of the motor board determination process of the present application). After executing S11, the ASIC 72 executes S10.

[0094] In S10, the ASIC 72 transitions the tri-state logic circuit 131 to the third state and outputs a third control signal CL3 to stop the polygon motor 89. Next, the ASIC 72 executes preparatory processing based on the manufacturer information of the polygon motor substrate 78 stored in the volatile memory 74 in S9 or S11 (S12). As the preparatory processing, the ASIC 72 executes, for example, processing to check the operation of the motors of each drive source. The ASIC 72 outputs a first control signal CL1 and a motor clock signal CLK. After a predetermined waiting time has elapsed since the input of a low-level LOCKn signal LOCKn, the ASIC 72 causes the semiconductor laser 77 to emit light and determines whether there is an abnormality in the rotational operation of the polygon motor 89 based on the detection signals Vo1 and Vo2 of the first and second BD sensors 83 and 84. The ASIC 72 reads and uses, as this waiting time, information on the waiting time corresponding to the manufacturer determined in the processing of FIG. 6 from among the waiting times (control parameters) for each manufacturer stored in the non-volatile memory 76.

[0095] Furthermore, the content of the preparation process is not limited to the process of checking the operation of the polygon motor 89. The ASIC 72 may perform other processes as preparation processes, such as driving the agitator of the developer cartridge 33 to agitate the toner, rotating the pickup roller 21 and the transport roller 23 to check the operational state of the transport path, and warming up the fixing device 5. In this case, parameters corresponding to the manufacturer determined by a determination process similar to that shown in FIG. 6 may be used as parameters for controlling the operation of the motors of each drive source. Therefore, motors other than the polygon motor 89 (such as a main motor), i.e., motors for other purposes that may be provided in the image forming apparatus, may be used as the motors of the present application. For motors for other purposes, a process of determining the manufacturer by switching control signals may be performed, similar to the determination process shown in FIG. 6, and the preparation process may be performed using control parameters corresponding to the determination result.

[0096] 6 when it completes the preparation process in S12. The ASIC 72 executes printing and the like based on the acceptance of the print job. Furthermore, the ASIC 72 maintains the manufacturer information stored in the volatile memory 74 in S9 or S11 while the printer 10 is powered on. When the ASIC 72 executes control of the polygon motor 89, it executes control of the motor driver 87 using control parameters corresponding to the manufacturer information stored in the volatile memory 74.

[0097] 6 again, and stores and uses the determined information about the manufacturer of the polygon motor board 78 in the volatile memory 74. In this way, the ASIC 72 of this embodiment can determine the manufacturer of the polygon motor board 78 based on the operation of the polygon motor board 78 when the second control signal CL2 is output, and can perform control using appropriate parameters as parameters for controlling the polygon motor 89.

[0098] As described above, the first embodiment provides the following effects. (1) The printer 10 of this embodiment can be fitted with one of multiple types of polygon motor boards 78 (first polygon motor board 78A, second polygon motor board 78B). The ASIC 72 has a polygon motor terminal 102 connected to the polygon motor board 78 via wiring 125. The ASIC 72 outputs an ON signal ON from the polygon motor terminal 102 to rotate the polygon motor terminal 102, and can switch between and output at least as many ON signals ON as there are types of polygon motor boards 78 (for example, two types).

[0099] According to this, the ASIC 72 switches between outputting an ON signal from the polygon motor terminal 102, thereby determining the type of the attached polygon motor board 78 based on the presence or absence of rotation of the polygon mirror 92. Based on the determination result, control parameters according to the type (manufacturer) of the polygon motor 89 can be used for control. Furthermore, since the ASIC 72 outputs an ON signal ON by switching it from one output terminal (polygon motor terminal 102) that outputs an ON signal ON for rotating the polygon motor 89, the ASIC 72 can determine the type of polygon motor board 78 without adding dedicated wiring between the ASIC 72 and the polygon motor board 78 for determining the type of polygon motor board 78. For example, when the laser unit 31 is replaced, the ASIC 72 can determine the type of polygon motor board 78 and use appropriate control parameters to control the polygon motor 89. In addition to setting control parameters, when a printing defect occurs, for example, the ASIC 72 can also record in a log or report to a server which type of polygon motor board 78 (laser unit 31) is causing the printing defect.

[0100] (2) The ASIC 72 also outputs an ON signal ON from the polygon motor terminal 102, and determines the type of polygon motor board 78 that is mounted based on whether the polygon motor 89 is rotating or not. According to this, the ASIC 72 switches and outputs the ON signal from the polygon motor terminal 102, and it is possible to determine the type of polygon motor board 78 that is mounted based on whether or not the polygon motor 89 is rotating.

[0101] (3) In addition, the ASIC 72 can output a Start signal indicating the start of rotational drive or a Stop signal instructing the motor driver 87 to stop rotational drive via the polygon motor terminal 102, and outputs an ON signal ON indicating the Start signal from the polygon motor terminal 102. According to this, the ASIC 72 can determine the type of polygon motor board 78 by outputting multiple types of ON signals ON using the polygon motor terminal 102, which outputs a Start signal to the motor driver 87 to indicate the start of rotational drive or a Stop signal to instruct the motor driver 87 to stop, thereby eliminating the need for dedicated wiring to determine the polygon motor board 78.

[0102] (4) The ASIC 72 also has a three-state logic circuit 131 that can output any one of the first to third control signals CL1 to CL3 from the polygon motor terminal 102. The first polygon motor board 78A manufactured by company A puts the polygon motor 89 into a rotating state when the first control signal CL1 or the second control signal CL2 is input, and puts the polygon motor 89 into a stopped state when the third control signal CL3 is input. On the other hand, the second polygon motor board 78B manufactured by company B puts the polygon motor 89 into a rotating state when the first control signal CL1 is input, and puts the polygon motor 89 into a stopped state when the second control signal CL2 or the third control signal CL3 is input.

[0103] According to this, the ASIC 72 can output one of the first to third control signals CL1 to CL3 from the polygon motor terminal 102 by controlling the tri-state logic circuit 131. By outputting the first to third control signals CL1 to CL3, the ASIC 72 can instruct the polygon motor 89 to start or stop rotation. Furthermore, when the ASIC 72 outputs the second control signal CL2, it can determine the type of polygon motor board 78 that is attached by determining whether the polygon motor 89 is rotating or stopped.

[0104] (5) The ASIC 72 also outputs a first control signal CL1 from the polygon motor terminal 102 to the mounted polygon motor board 78, and determines whether the polygon motor board 78 of the mounted polygon motor board 78 rotates (S2, S3). After executing S3, the ASIC 72 outputs a second control signal CL2, and determines whether the polygon motor 89 of the mounted polygon motor board 78 rotates (S7, S8). If the polygon motor 89 rotates in response to both the first and second control signals CL1 and CL2 (S3: YES, S8: YES), the ASIC 72 determines that the first polygon motor board 78A is mounted (S9). If the polygon motor 89 rotates in response to the first control signal CL1 but does not rotate in response to the second control signal CL2 (S3: YES, S8: NO), the ASIC 72 determines that the second polygon motor board 78B is mounted (S11). According to this, the ASIC 72 can use the first and second control signals CL1, CL2 to determine whether the attached polygon motor board 78 is the first polygon motor board 78A or the second polygon motor board 78B based on whether the polygon motor 89 is rotating or not.

[0105] (6) Furthermore, when the power of the printer 10 is turned on, the ASIC 72 starts the process of FIG. According to this, if the laser unit 31 is replaced and the type of polygon motor board 78 is changed while the power is off, the type of polygon motor board 78 can be determined when the power is turned on, and control parameters can be set and used for control according to the type of polygon motor board 78. This allows for more appropriate control of the polygon motor 89, improving the accuracy of image formation.

[0106] (7) In addition, if the ASIC 72 determines in S3 that the polygon motor 89 is not rotating (S3: NO), it determines that an error has occurred (S6), and if it determines that the polygon motor 89 is rotating (S3: YES), it executes S7 and S8. According to this, the ASIC 72 executes S3 before executing S7 and S8, and if the polygon motor 89 does not rotate in response to the first control signal CL1, it determines that an error has occurred. If the polygon motor 89 does not rotate despite having output the first control signal CL1 that should cause the polygon motor 89 to rotate regardless of whether it is made by company A or company B, there is a high possibility that the polygon motor 89 is malfunctioning. For this reason, by reporting an error without determining the type of polygon motor board 78, it is possible to urge the user to replace the laser unit 31, for example.

[0107] (8) After executing S9 or S11, the ASIC 72 executes a preparatory process for forming an image using parameters according to the determined type of polygon motor board 78 (S12). According to this, by using parameters according to the type of polygon motor board 78, the polygon motor 89 can be rotated with precision in the preparatory processing for forming an image, and the preparatory processing can be executed appropriately.

[0108] (9) The ASIC 72 also stores the information about the polygon motor board 78 determined in S9 and S11 in the volatile memory 74, and maintains the information about the polygon motor board 78 stored in the volatile memory 74 while the printer 10 is powered on. When the power is turned off and then on again, the ASIC 72 executes the process of FIG. 6 and stores the information about the determined polygon motor board 78 in the volatile memory 74.

[0109] According to this, while the power of the printer 10 is on, parameters and the like used for forming an image can be set based on information about the type of polygon motor board 78 stored in the volatile memory 74. Furthermore, when the power is turned off and then turned on again, the type of polygon motor board 78 attached at startup can be determined by executing the process of Fig. 6, and information about the determined type can be stored in the volatile memory 74. In cases such as when the laser unit 31 is replaced while the power is off, the type of polygon motor board 78 of the newly attached laser unit 31 can be determined when the power is turned on.

[0110] (10) The ASIC 72 also receives the LOCKn signal LOCKn from the motor driver 87, and in the processes of S3 and S8 in FIG. 6, determines whether the polygon motor 89 is rotating based on the LOCKn signal LOCKn. This allows the ASIC 72 to determine whether or not the polygon motor 89 is rotating based on the LOCKn signal LOCKn input from the first and second motor drivers 87A and 87B.

[0111] (11) Furthermore, each of the first and second polygon motor substrates 78A and 78B rotates the polygon motor 89 when an ON signal ON greater than a predetermined voltage level is input from the polygon motor terminal 102, and stops the polygon motor 89 when an ON signal ON equal to or less than the predetermined voltage level is input. The resistance value of the first pull-up resistor Rup1 of the first polygon motor substrate 78A is different from the resistance value of the second pull-up resistor Rup2 of the second polygon motor substrate 78B. The main substrate 71 has a pull-down resistor Rdown, one end of which is connected to the wiring 125 and the other end of which is connected to ground GND. When the ASIC 72 outputs a high-impedance signal as the second control signal CL2 from the polygon motor terminal 102, the voltage generated by the first power supply unit Vcc1 is divided by the first pull-up resistor Rup1 (or the second pull-up resistor Rup2) and the pull-down resistor Rdown, and the divided voltage is input to the polygon motor substrate 78. The resistance value of the pull-down resistor Rdown is set so that when the mounted polygon motor substrate 78 is the first polygon motor substrate 78A (see Figure 4), an input voltage Vin greater than a predetermined voltage level is input from the polygon motor terminal 102, and when the mounted polygon motor substrate 78 is the second polygon motor substrate 78B (see Figure 5), an input voltage Vin less than the predetermined voltage level is input from the polygon motor terminal 102.

[0112] According to this, when the second control signal CL2 is output, the second control signal CL2 of different voltage levels is input to the first polygon motor substrate 78A and the second polygon motor substrate 78B. The second control signal CL2 can cause one of the first and second polygon motor substrates 78A, 78B to rotate and the other to stop. By checking the operation of the polygon motor 89 when the second control signal CL2 is output, the type of polygon motor substrate 78 can be determined.

[0113] (12) Furthermore, the first polygon motor substrate 78A has a first pull-up resistor Rup1 arranged outside the first motor driver 87A, and the second polygon motor substrate 78B has a second pull-up resistor Rup2 arranged inside the second motor driver 87B. According to this, when the mounted polygon motor substrate 78 is the first polygon motor substrate 78A, the voltage generated by the first power supply unit Vcc1 is divided by the first pull-up resistor Rup1 and pull-down resistor Rdown external to the first motor driver 87A, and the divided voltage is input to the first polygon motor substrate 78A. Furthermore, when the mounted polygon motor substrate 78 is the second polygon motor substrate 78B, the voltage generated by the first power supply unit Vcc1 is divided by the second pull-up resistor Rup2 and pull-down resistor Rdown inside the second motor driver 87B, and the divided voltage is input to the second polygon motor substrate 78B.

[0114] (Second embodiment) Next, a second embodiment of the present invention will be described. In the first embodiment described above, information about the determined manufacturer is stored in volatile memory 74 in S9 and S11 of the determination process in FIG. 6. In contrast, the second embodiment differs from the first embodiment in that information about the determined manufacturer is stored in non-volatile memory 76. FIGS. 7 and 8 show flowcharts of the determination process according to the second embodiment. In the following description, the same components and steps as those in the first embodiment described above are denoted by the same reference numerals, and their description will be omitted as appropriate.

[0115] 7 when the printer 10 is powered on, the ASIC 72 starts the processing of Fig. 7, and in S21 determines whether information on the result of determining the manufacturer of the polygon motor board 78 has already been stored in the non-volatile memory 76 (an example of the memory confirmation processing of the present application). If the information on the determination result has already been stored (S21: YES), the ASIC 72 executes the preparation processing of S12 based on the stored information, and if the information on the determination result has not been stored (S21: NO), it executes the motor determination processing of S22.

[0116] As shown in Fig. 8, when the ASIC 72 starts the motor determination process of S22, it executes the processes of S1 to S8, as in the first embodiment. If the ASIC 72 determines in S8 that the polygon motor 89 is rotating (S8: YES), it stores information indicating that a laser unit 31 equipped with a first polygon motor board 78A manufactured by company A is installed in the nonvolatile memory 76 (S25). If the ASIC 72 determines that the polygon motor 89 is not rotating (S8: NO), it stores information indicating that a laser unit 31 equipped with a second polygon motor board 78B manufactured by company B is installed in the nonvolatile memory 76 (S26). After executing S25 or S26, the ASIC 72 stops the rotation of the polygon motor 89 (S10) and ends the process shown in Fig. 8.

[0117] On the other hand, if the ASIC 72 determines in S3 that the polygon motor 89 is not rotating (S3: NO), it notifies an error and stops the polygon motor 89 (S27), similar to S6 in Fig. 6. The ASIC 72 also stores an error flag indicating that an error has occurred in, for example, the volatile memory 74 (S27), and ends the processing shown in Fig. 8.

[0118] 7, when the motor determination process of S22 ends, the ASIC 72 determines whether an error has occurred in the motor determination process (S29). If an error flag is set in the volatile memory 74, the ASIC 72 determines that an error has occurred (S29: YES), and ends the process shown in FIG.

[0119] On the other hand, if no error flag is stored in the volatile memory 74, the ASIC 72 determines that no error has occurred (S29: NO) and executes S12. In S12, the ASIC 72 executes preparatory processing similar to the first embodiment based on the information on the determination result (manufacturer) stored in the non-volatile memory 76. When the preparatory processing of S12 is completed, the ASIC 72 ends the processing shown in FIGS. 7 and 8.

[0120] Therefore, in the second embodiment, if manufacturer information is already stored in the nonvolatile memory 76 (S21: YES), the ASIC 72 does not execute the motor determination process of S22, but instead reads control parameters corresponding to the stored manufacturer information from the nonvolatile memory 76 and executes the preparation process (S12). On the other hand, if manufacturer information is not stored in the nonvolatile memory 76 (S21: NO), the ASIC 72 executes the motor determination process of S22, determines the manufacturer of the polygon motor board 78, stores the determined manufacturer in the nonvolatile memory 76, and then executes the preparation process of S12. This allows the information in the nonvolatile memory 76 to be used instead of executing the process of determining the manufacturer of the polygon motor board 78 each time the printer 10 is turned on.

[0121] The ASIC 72 may erase the manufacturer information stored in the nonvolatile memory 76 based on a predetermined condition. For example, the ASIC 72 may erase the information in the nonvolatile memory 76 when it detects that the laser unit 31 has been removed. Alternatively, the ASIC 72 may erase the information in the nonvolatile memory 76 when a predetermined period of time has elapsed since the manufacturer information was stored in the nonvolatile memory 76.

[0122] As described above, the second embodiment provides the same effects as the first embodiment. Furthermore, the second embodiment provides the following effects. (1) The ASIC 72 of the second embodiment stores information about the manufacturer of the polygon motor substrate 78 determined in the process of Fig. 8 in the nonvolatile memory 76 (S25, S26). Then, the next time the printer 10 is turned on, the ASIC 72 determines whether or not information about the manufacturer of the polygon motor substrate 78 is stored in the nonvolatile memory 76 (S21 of Fig. 7). If information about the polygon motor substrate 78 is stored in the nonvolatile memory 76 (S21: YES), the ASIC 72 does not execute the process of Fig. 8, and if information about the polygon motor substrate 78 is not stored in the nonvolatile memory 76 (S21: NO), the ASIC 72 executes the process of Fig. 8 (S22).

[0123] According to this, by storing information about the type of polygon motor substrate 78 determined at the previous startup in the nonvolatile memory 76, the stored information can be reused the next time the power is turned on again, eliminating the need to execute the process of FIG. 8 every time the power is turned on. Furthermore, if for some reason information is not stored in the non-volatile memory 76, the type of polygon motor board 78 of the laser unit 31 currently installed can be determined by executing the process of Figure 8, and the determined type can be stored in the non-volatile memory 76.

[0124] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiments, the polygon mirror 92 is used as the drive unit of the present invention, and the polygon motor 89 is used as the motor. However, this is not limiting. For example, the photosensitive drum 41 may be used as the drive unit. In this case, a process motor that drives the photosensitive drum 41 may be used as the motor of the present invention. Alternatively, the fixing device 5, pickup roller 21, separation roller 22, conveyance roller 23, drive roller 61, etc. may be used as the drive unit. In this case, a main motor that drives the fixing device 5 and each roller may be used as the motor of the present invention. Alternatively, the flapper 28 may be used as the drive unit, and a motor that operates the flapper 28 may be used as the motor. Therefore, the ASIC 72 may determine the type of motor board based on whether each roller rotates, whether the photosensitive drum 41 rotates, whether the sheet S is conveyed, whether printing is successful, whether the flapper 28 switches the conveyance path, etc. Furthermore, although an ON signal ON is employed as the control signal in the present application, this is not limiting. For example, a motor clock signal CLK may be employed as the control signal in the present application, and the polygon motor terminal 103 may be employed as the output terminal. In this case, the ASIC 72 may, for example, switch between a first status (high-level signal) and a second status (impedance signal) at a predetermined frequency, and output the motor clock signal CLK, in which a high-level signal and a high-impedance signal are alternately repeated, from the polygon motor terminal 103 to the polygon motor substrate 78. The ASIC 72 may then determine the type of polygon motor substrate 78 depending on whether the polygon motor 89 rotates in response to the input of the motor clock signal CLK.

[0125] 4 and 5 show only examples of the signal levels of the first to third control signals CL1 to CL3, the on / off states of the first switch element SW1 and the second switch element SW2, and the rotation state of the polygon motor 89. Furthermore, in each of the above embodiments, the type of polygon motor board 78 is determined for two types, but this is not limited to this. For example, for three or more types of polygon motor board 78, the type of polygon motor board 78 may be determined by switching the control signal. For example, the ASIC 72 may determine the type of three or more types of polygon motor board 78 by combining the ON signal ON and the motor clock signal CLK. Furthermore, the ASIC 72 executes the process of FIG. 6 to determine the type of polygon motor board 78 and executes the preparation process based on the determination result, but the preparation process does not have to be executed. Furthermore, the ASIC 72 may be configured to execute the processes from S7 onwards without executing S1 to S5. In this case, the type of polygon motor board 78 can be determined by the second control signal CL2.

[0126] Furthermore, in the above-described embodiments, a color laser printer capable of color printing is employed as the image forming apparatus of the present application, but this is not limited thereto. The image forming apparatus of the present application may also be a monochrome laser printer. Therefore, the image forming apparatus of the present application may be configured to include only one set of an LD driver and a semiconductor laser. Furthermore, the laser unit of the present application is not limited to a device used for printing, but may also be a device used for scanning, such as a laser scanner. Therefore, the image forming apparatus of the present application is not limited to a printer, but may also be a scanner or a fax machine. Furthermore, the image forming apparatus of the present application may also be a multifunction device equipped with multiple functions, such as a printing function, a copying function, a fax function, and a scanning function. Therefore, the configuration of the laser unit is appropriately changed depending on the functions of the image forming apparatus. [Explanation of symbols]

[0127] 10 color laser printer (image forming apparatus), 3 conveying section (driving section), 4 process section (image forming section), 5 fixing device (driving section), 31 laser unit, 41 photosensitive drum, 71 main board, 72 ASIC (controller), 74 volatile memory, 76 non-volatile memory, 77 semiconductor laser, 78 polygon motor board (motor board), 78A first polygon motor board (motor board), 78B second polygon motor board (motor board), 87 motor driver, 87A first motor driver, 87B second motor driver, 89 polygon motor (motor, first polygon motor, second polygon motor), 92 polygon mirror (driving section), 102, 103 polygon motor terminal (output terminal), 125, 126 wiring, 131 three-state logic circuit, ON ON signal (control signal), CL1 first control signal, CL2 second control signal, CL3 third control signal, CLK Motor clock signal (control signal), GND ground, LOCKn LOCKn signal, Rdown pull-down resistor, Rup1 first pull-up resistor (pull-up resistor), Rup2 second pull-up resistor (pull-up resistor), S sheet, Vcc1 first power supply unit (power supply unit), Vin input voltage (signal).

Claims

1. An image forming apparatus for forming an image on a sheet, A drive unit; a motor board on which a motor that rotates the drive unit is mounted; A controller; Equipped with The motor board can be mounted with any one motor board selected from a plurality of types of motor boards, The controller an output terminal connected to a motor board mounted on the image forming apparatus via a wiring, and a control signal for rotating the motor is output from the output terminal, and the control signal can be switched and output according to at least the number of types of the motor board; Image forming device.

2. The controller outputting the control signal from the output terminal, and determining the type of the mounted motor board based on whether or not the motor is rotating; The image forming apparatus according to claim 1 .

3. The controller A Start signal indicating the start of rotation driving or a Stop signal instructing the stop of rotation driving can be output to a motor driver of a motor board attached to the image forming apparatus via the output terminal, outputting a control signal indicating a Start signal from the output terminal; The image forming apparatus according to claim 2 .

4. further comprising an image forming unit for forming an image on the sheet; The image forming unit includes: a laser unit including a semiconductor laser, a polygon mirror serving as the drive unit and deflecting light from the semiconductor laser, and a polygon motor board serving as the motor board on which a polygon motor for rotating the polygon mirror and a motor driver for driving the polygon motor are mounted, the laser unit being capable of mounting one of a plurality of types of polygon motor boards, and a photosensitive drum exposed to light deflected by the polygon mirror; The laser unit includes: Either a first polygon motor substrate on which a first polygon motor and a first motor driver are mounted, or a second polygon motor substrate on which a second polygon motor and a second motor driver are mounted, can be mounted; The controller a tri-state logic circuit capable of outputting any one of a first control signal, a second control signal, and a third control signal from the output terminal; In the laser unit, When the mounted polygon motor substrate is the first polygon motor substrate, the first polygon motor is in a rotating state when the first control signal or the second control signal is input, and the first polygon motor is in a stopped state when the third control signal is input, When the mounted polygon motor substrate is the second polygon motor substrate, the second polygon motor is in a rotating state when the first control signal is input, and the second polygon motor is in a stopped state when the second control signal or the third control signal is input. The image forming apparatus according to claim 2 .

5. The controller a first rotation determination process for outputting the first control signal from the output terminal to the mounted polygon motor board and determining whether or not the polygon motor of the mounted polygon motor board rotates; a second rotation determination process for outputting the second control signal from the output terminal to the mounted polygon motor board after the first rotation determination process, and determining whether or not the polygon motor of the mounted polygon motor board rotates; In the first rotation determination process and the second rotation determination process, if the polygon motor of the attached polygon motor board is rotating, it is determined that the first polygon motor board is attached to the laser unit, a motor board determination process for determining that the second polygon motor board is attached to the laser unit when the polygon motor of the attached polygon motor board rotates in the first rotation determination process and the polygon motor of the attached polygon motor board does not rotate in the second rotation determination process; 5. The image forming apparatus according to claim 4, wherein the image forming apparatus executes the following.

6. The controller When the power supply of the image forming apparatus is turned on, Executing the first rotation determination process, the second rotation determination process, and the motor substrate determination process. The image forming apparatus according to claim 5 .

7. The controller In the first rotation determination process, if it is determined that the polygon motor is not rotating, it is determined that an error has occurred; When it is determined in the first rotation determination process that the polygon motor is rotating, the second rotation determination process and the motor substrate determination process are executed. The image forming apparatus according to claim 5 .

8. The controller 6. The image forming apparatus according to claim 5, wherein after the motor substrate determination process is executed, a preparatory process is executed for forming an image using parameters according to the type of polygon motor of the polygon motor substrate determined by the motor substrate determination process.

9. The controller storing information about the polygon motor substrate determined in the motor substrate determination process in a volatile memory, and maintaining the information about the polygon motor substrate stored in the volatile memory while the power supply of the image forming apparatus is turned on; When the power supply of the image forming apparatus is turned off and then turned on again, the first rotation determination process, the second rotation determination process, and the motor substrate determination process are executed, and information on the polygon motor substrate determined in the motor substrate determination process is stored in the volatile memory. The image forming apparatus according to claim 5 .

10. The controller storing information on the polygon motor substrate determined in the motor substrate determination process in a nonvolatile memory; When the power supply of the image forming apparatus is turned on, a memory confirmation process is executed to confirm whether or not information on the polygon motor board is stored in the nonvolatile memory; If the result of the memory confirmation process is that information on the motor board is stored in the nonvolatile memory, the first rotation determination process, the second rotation determination process, and the motor board determination process are not executed, If the result of the memory confirmation process is that the information on the polygon motor substrate is not stored in the nonvolatile memory, the first rotation determination process, the second rotation determination process, and the motor substrate determination process are executed. The image forming apparatus according to claim 5 .

11. the first motor driver and the second motor driver are capable of outputting a LOCKn signal indicating whether or not the polygon motor has rotated a predetermined number of times to the controller; The controller The LOCKn signal is input from the motor driver of the mounted motor board, In the first rotation determination process and the second rotation determination process, 6. The image forming apparatus according to claim 5, wherein it is determined whether or not the polygon motor of the polygon motor board mounted thereon is rotating based on the LOCKn signal.

12. The mounted polygon motor board is a power supply unit; and a pull-up resistor having one end connected to the wiring and the other end connected to the power supply unit, the mounted polygon motor board rotates the polygon motor when a signal greater than a predetermined voltage level is input from the output terminal, and stops the polygon motor when a signal equal to or less than the predetermined voltage level is input from the output terminal; the first polygon motor substrate and the second polygon motor substrate respectively have, as the pull-up resistors, first pull-up resistors and second pull-up resistors which are resistances of different values; a main board on which the controller is mounted, the main board has a pull-down resistor, one end of which is connected to the wiring and the other end of which is connected to ground; The controller when a high-impedance signal is output as the second control signal from the output terminal, a voltage generated by the power supply unit is divided by the pull-up resistor and the pull-down resistor, and the divided voltage is input to the polygon motor board, The resistance value of the pull-down resistor is When the controller outputs the second control signal and the mounted polygon motor substrate is the first polygon motor substrate, a signal greater than the predetermined voltage level is input from the output terminal, and when the controller outputs the second control signal and the mounted polygon motor substrate is the second polygon motor substrate, a signal equal to or less than the predetermined voltage level is input from the output terminal. The image forming apparatus according to claim 4 .

13. the first polygon motor substrate has the first pull-up resistor disposed outside the first motor driver; the second polygon motor substrate has the second pull-up resistor disposed inside the second motor driver; The image forming apparatus according to claim 12.

Images