Optical writing device, image forming apparatus, maintenance assistance method, and program product

Abstract

The present invention relates to an optical writing device, an image forming apparatus, a maintenance assistance method, and a computer program product, the optical writing device comprising: a polygon mirror (212) that deflects a light beam; an optical sensor (403) disposed at a position where the light beam deflected by the polygon mirror (212) is incident; a housing case (300) that houses the polygon mirror (212) in an internal space; and an adjustment member (401) that adjusts a photoelectric conversion gain with respect to incident light to the optical sensor (403), the adjustment member (401) being disposed outside the housing case (300).

Description

Technical Field

[0001] The present invention relates to an optical writing apparatus, an image forming apparatus, a maintenance assistance method, and a maintenance assistance program, and particularly to an optical writing apparatus that emits light deflected in one direction, an image forming apparatus equipped with the optical writing apparatus, a maintenance assistance method executed by the image forming apparatus, and a computer program product that causes a computer to execute the maintenance assistance method. Background Technology

[0002] Image forming apparatuses, such as MFP (Multi-Function Peripheral), form an electrostatic latent image on an image carrier by exposing it to a charged image carrier, and then form a toner image on the image carrier by developing the electrostatic latent image using a toner.

[0003] For example, Japanese Patent Application Publication No. 2018-196942 discloses an image forming apparatus characterized by comprising: a photosensitive drum; a laser light source; a rotating polygonal mirror that scans the laser on the photosensitive drum; a synchronization sensor that generates a synchronization signal in the main scanning direction by receiving the scanned laser at a predetermined position; a drive circuit that drives the light source; and a control circuit that uses the drive circuit to control the emission amount of the light source based on the synchronization signal, wherein the control circuit determines the pulse width of the synchronization signal in an exposure adjustment process, and uses the drive circuit to cause the light source to emit the laser with an emission amount corresponding to the pulse width, thereby adjusting the exposure amount of the laser on the photosensitive drum to a predetermined value.

[0004] Because of its rotation, a rotating polyhedron tends to concentrate contamination on a portion of its reflective surface. It is assumed that dust is drawn into the airflow generated by the mirror's rotation and adheres to this portion of the reflective surface. In this dust-laden area, the reflectivity of light decreases. Therefore, if the light received by a light sensor is reflected from this dust-laden area, there is a possibility that the light sensor may fail to detect it.

[0005] The precision of the position at which the exposure unit illuminates the image carrier affects the image quality formed by the image forming apparatus. The optical path from the point of illumination within the exposure unit to the point of illumination on the image carrier needs to be kept constant. Therefore, cleaning the reflective surfaces of the rotating polygon mirror is also considered, but disassembling the exposure unit requires advanced skills.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-196942 Summary of the Invention

[0007] One of the objectives of this invention is to provide an easy-to-maintain optical writing device.

[0008] Another object of the present invention is to provide an image forming apparatus that is easy to maintain.

[0009] Another object of the present invention is to provide an easy-to-maintain maintenance aid method.

[0010] Another object of the present invention is to provide a computer program product that is easy to maintain.

[0011] According to one aspect of the present invention, an optical writing device includes: a faceted mirror for deflecting a light beam; a light sensor disposed at the position where the light beam deflected by the faceted mirror is incident; a housing housing that houses the faceted mirror in an internal space; and an adjustment member for adjusting the photoelectric conversion gain relative to the incident light toward the light sensor, the adjustment member being disposed outside the housing housing.

[0012] According to another aspect of the present invention, the image forming apparatus includes the above-described optical writing device.

[0013] According to another aspect of the present invention, the maintenance assistance method is a maintenance assistance method performed by the above-described optical writing device, comprising: a resistance value determination step, determining the resistance value of the adjustment component; and a display control step, displaying the resistance value determined in the resistance value determination step.

[0014] According to another aspect of the present invention, the maintenance assistance program is a maintenance assistance program executed by a computer that controls the optical writing device, which causes the computer to perform: a resistance value determination step, which determines the resistance value of the adjustment component; and a display control step, which displays the resistance value determined in the resistance value determination step. Attached Figure Description

[0015] Figure 1 This is a perspective view showing the appearance of the MFP in one embodiment of the present invention.

[0016] Figure 2 This is a schematic cross-sectional view showing the internal structure of the MFP.

[0017] Figure 3 This is a diagram illustrating an example of the internal structure of an exposure unit.

[0018] Figure 4 It is a top view showing the interior of the exposure unit.

[0019] Figure 5 It is a 3D view of the exposure unit.

[0020] Figure 6 This is a top view of the exposure unit.

[0021] Figure 7 This is a diagram illustrating an example of the tendency of multifaceted mirrors to become contaminated.

[0022] Figure 8 This is a circuit diagram representing an example of a circuit formed on a base substrate.

[0023] Figure 9 The first figure is an example of an analog output and digital signal of a base substrate.

[0024] Figure 10 The second figure is an example of the analog output and digital signal of the base substrate.

[0025] Figure 11 The third figure is an example of an analog output and digital signal from a base substrate.

[0026] Figure 12 This is a diagram representing an example of a correspondence table.

[0027] Figure 13 This is a block diagram illustrating the general hardware structure of the MFP in this embodiment.

[0028] Figure 14 This is a block diagram illustrating one example of the functions of the CPU 111 in the MFP of this embodiment.

[0029] Figure 15 This is a flowchart illustrating an example of a maintenance support process.

[0030] Figure 16 This is a diagram representing an example of the correspondence table in the first variation.

[0031] Figure 17 This is a diagram representing an example of the correspondence table in the second variation.

[0032] Figure 18 This is a diagram representing an example of the correspondence table in the third variation.

[0033] Figure 19 This is a diagram representing an example of the correspondence table in the fourth variation.

[0034] Figure 20 This is a diagram representing an example of the correspondence table in the fifth variation.

[0035] Figure 21 This is a diagram representing an example of the correspondence table in the sixth variation.

[0036] Figure 22 This is a diagram representing an example of the correspondence table in the seventh variation.

[0037] Figure 23 This is a diagram illustrating one example of the functions of the CPU 111 in the MFP100 of the eighth variant.

[0038] Figure 24 This is a diagram representing an example of the correspondence table in the eighth variation.

[0039] Figure 25 This is a flowchart illustrating an example of the maintenance auxiliary processing flow in the eighth variation.

[0040] Figure 26 This is a diagram representing an example of the correspondence table in the ninth variation. Detailed Implementation

[0041] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals are used to denote the same parts. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0042] Figure 1 This is a perspective view showing the appearance of an MFP according to one embodiment of the present invention. Figure 1 In the accompanying drawings, arrows indicating the mutually orthogonal X, Y, and Z directions are used. The X and Y directions are orthogonal in the horizontal plane, and the Z direction corresponds to the vertical direction. Furthermore, in the following description, in the X direction, the direction the arrow points is referred to as right, and its opposite direction as left. Similarly, in the Y direction, the direction the arrow points is referred to as forward, and its opposite direction as backward.

[0043] Reference Figure 1 The MFP (Multi-Function Peripheral) 100 is an example of an image forming apparatus. The MFP 100 includes an automatic document feeder 120, a document reading unit 130, an image forming unit 140, a paper feed unit 150, and an operation panel 160 as a user interface.

[0044] The automatic document transport device 120 automatically transports multiple original documents, one by one, from the original document tray to the original document reading position of the original document reading unit 130. After the original document reading unit 130 reads the image formed on the original document, it discharges the original document onto the original document output tray. The original document reading unit 130 optically reads the image formed on the original document and performs photoelectric conversion. The original document reading unit 130 outputs the image data obtained through photoelectric conversion to the image forming unit 140.

[0045] The paper supply unit 150 supplies paper to the image forming unit 140. Based on image data, the image forming unit 140 forms an image on the paper fed by the paper supply unit 150 using a known electronic photographic method. The image forming unit 140 forms an image of the image data onto the paper fed by the paper supply unit 150. The paper with the image formed by the image forming unit 140 is discharged into the paper discharge tray 39.

[0046] The operation panel 160 is the user interface. The operation panel 160 is located on the upper part of the MFP100. The operation panel 160 includes a display section and an operation section.

[0047] Figure 2 This is a schematic cross-sectional view showing the internal structure of the MFP. (See reference...) Figure 2 The original document reading unit 130 exposes the image of the original document, which is set on the original document glass 11 by the automatic original document transport device 120, using an exposure lamp 13 mounted on a slider 12 that moves below it. The reflected light from the original document is guided to the lens 16 through the mirror 14 and two mirrors 15, 15A, and imaged on the CCD (Charge Coupled Device) sensor 18.

[0048] The reflected light imaged on the CCD sensor 18 is converted into image data as an electrical signal within the CCD sensor 18. The image data is converted into printing data in yellow (Y), magenta (M), cyan (C), and black (K) and output to the image forming unit 140.

[0049] The exposure unit 21 generates light beams corresponding to yellow, magenta, cyan, and black, respectively, based on the printing data (electrical signals) received from the original document reading unit 130.

[0050] The image forming unit 140 includes developing units 20Y, 20M, 20C, and 20K, and corresponding removable toner bottles 41Y, 41M, 41C, and 41K. The toner bottles 41Y, 41M, 41C, and 41K respectively contain yellow, magenta, cyan, and black toners. Here, "Y", "M", "C", and "K" represent yellow, magenta, cyan, and black, respectively. The toners in the toner bottles 41Y, 41M, 41C, and 41K are supplied to the developing units 20Y, 20M, 20C, and 20K, respectively.

[0051] An image is formed by driving at least one of the developing units 20Y, 20M, 20C, and 20K. If all of the developing units 20Y, 20M, 20C, and 20K are driven, a full-color image is formed. Printing data for yellow, magenta, cyan, and black are input to the developing units 20Y, 20M, 20C, and 20K, respectively. The developing units 20Y, 20M, 20C, and 20K differ only in the color of the toner they process; therefore, the developing unit 20Y, used to form a yellow image, will be described here.

[0052] The developing unit 20Y includes a photosensitive drum (image carrier) 23Y, an electrified roller 22Y, a developer 24Y, and a primary transfer roller 25Y.

[0053] Exposure unit 21 emits a light beam corresponding to the photoreceptor drum 23Y, scanning the surface of the photoreceptor drum 23Y in the main scanning direction. Exposure unit 21 illuminates the light beam with data based on the yellow printed characters, so that the light beam is scanned on the photoreceptor drum 23Y along the main scanning direction. Thus, the photoreceptor drum 23Y is exposed.

[0054] After being energized by the charged roller 22Y, the photosensitive drum 23Y is irradiated by the light beam emitted by the exposure unit 21. This forms an electrostatic latent image on the photosensitive drum 23Y. Next, toner is placed on the electrostatic latent image by the developer 24Y, forming a toner image on the photosensitive drum 23Y. The toner image formed on the photosensitive drum 23Y is then transferred to the intermediate transfer belt 30 via the primary transfer roller 25Y.

[0055] On the other hand, the intermediate transfer belt 30 is suspended by the drive roller 33 and the driven roller 34 to prevent slack. If the drive roller 33 rotates counterclockwise, the intermediate transfer belt 30 rotates counterclockwise at a predetermined speed. Accompanying the rotation of the intermediate transfer belt 30, the driven roller 34 rotates counterclockwise.

[0056] Thus, developing units 20Y, 20M, 20C, and 20K sequentially transfer toner images onto the intermediate transfer belt 30. The timing of the toner image transfers by developing units 20Y, 20M, 20C, and 20K onto the intermediate transfer belt 30 is adjusted by detecting the reference marks attached to the intermediate transfer belt 30. As a result, yellow, magenta, cyan, and black toner images are superimposed on the intermediate transfer belt 30.

[0057] Paper of different sizes is provided in paper feed cassettes 35, 35A, and 35B respectively. The paper contained in paper feed cassettes 35, 35A, and 35B is fed to the conveying path 40 by take-out rollers 36, 36A, and 36B respectively installed in paper feed cassettes 35, 35A, and 35B, and is then sent to the alignment roller pair 31 by the conveying roller 37.

[0058] The alignment roller pair 31 conveys the paper, which is conveyed by the conveyor roller 37, to the gap between the intermediate transfer belt 30 and the secondary transfer roller 26, which is a transfer component.

[0059] The secondary transfer roller 26 generates an electric field in the roller gap. In this gap, due to the electric field force, the toner image formed on the intermediate transfer belt 30 is transferred onto the paper conveyed by the registration rollers 31. The paper with the toner image transferred is conveyed to the fixing roller 32, where it is heated and pressurized. As a result, the toner dissolves and is fixed onto the paper. The paper is then discharged onto the paper discharge tray 39.

[0060] A cleaning squeegee 28 is provided upstream of the developing unit 20Y of the intermediate transfer belt 30. The cleaning squeegee 28 removes toner that remains on the intermediate transfer belt 30 and has not been transferred to the paper.

[0061] Furthermore, here we will describe an example of the MFP100 using a series configuration of developing units 20Y, 20M, 20C, and 20K, each capable of forming four colors of toner on paper. The MFP100 can also form an image using a four-cycle method, where the four colors of toner are sequentially transferred onto the paper using a single photosensitive drum.

[0062] Figure 3 This is a diagram illustrating an example of the internal structure of an exposure unit. Figure 3 In order to show the positional relationship between the exposure unit 21 and the photosensitive drums 23Y, 23M, 23C, and 23K, the exposure unit 21 is illustrated together with the developing units 20Y, 20M, 20C, and 20K. (Refer to...) Figure 3 The exposure unit 21 includes a light source unit 210, a polyhedral unit 211, and a first scanning lens 213. Additionally, the exposure unit 21 includes second scanning lenses 217Y, 217M, 217C, and 217K, first reflecting mirrors 215Y, 215M, 215C, and 215K, second reflecting mirrors 216Y, 216M, 216C, and 216K, and light-transmitting portions 219Y, 219M, 219C, and 219K. The light-transmitting portions 219Y, 219M, 219C, and 219K are disposed on the upper surface of the frame 300 of the exposure unit 21.

[0063] Figure 4 This is a top view showing the interior of the exposure unit. Figure 4 The diagram omits the optical components downstream of the first reflecting mirrors 215Y, 215M, 215C, and 215K. (Refer to...) Figure 3 as well as Figure 4The light source unit 210 illuminates four beams corresponding to the photosensitive drums 23Y, 23M, 23C, and 23K, respectively. The light source unit 210 is equipped with a set of light sources, collimating lenses, and reflectors for each of the photosensitive drums 23Y, 23M, 23C, and 23K. The light source is, for example, a semiconductor laser equipped with a photodiode. The beams illuminating from the light source are parallelized by the collimating lenses, reflected by the reflectors, and illuminate the exterior of the light source unit 210. The four reflectors are positioned at different heights to avoid blocking the beams reflected by the other reflectors. The beams illuminating from the light source unit 210 are reflected by the reflectors and guided to the polyhedral unit 211.

[0064] The polyhedral unit 211 includes a polyhedral mirror 212, a polyhedral motor 212M, and a housing 211A. The housing 211A has a closed space. The housing 211A houses the polyhedral mirror 212 and the polyhedral motor 212M within the closed space. The housing 211A is provided with transmission windows 211B and 211C for the light beam irradiated from the light source unit 210 to pass through.

[0065] The light beam emitted from the light source unit 210 passes through the transmission window 211B and illuminates the polygon mirror 212. The polygon mirror 212 is rotated in one direction by the polygon motor 212M, which deflects the light beam toward the main scanning direction.

[0066] More specifically, the yellow light beam emitted from the light source unit 210 is reflected by the rotating polygonal mirror 212 and deflected in the main scanning direction, then passes through the first scanning lens 213. The first scanning lens 213 corrects the direction of travel of the incident light beam so that the main scanning is performed at a constant speed on the photoreceptor drum 23Y. The light beam after passing through the first scanning lens 213 is redirected by the first reflecting mirror 215Y and guided to the second scanning lens 217Y. The light beam passing through the second scanning lens 217Y is redirected by the second reflecting mirror 216Y, passes through the light-transmitting portion 219Y, and reaches the outer peripheral surface of the photoreceptor drum 23Y.

[0067] The magenta light beam emitted from the light source unit 210 is reflected by the rotating polygonal mirror 212 and deflected in the main scanning direction, then passes through the first scanning lens 213. The first scanning lens 213 corrects the direction of travel of the incident light beam so that the main scanning is performed at a constant speed on the photoreceptor drum 23M. The light beam after passing through the first scanning lens 213 is redirected by the first reflecting mirror 215M and guided to the second scanning lens 217M. The light beam passing through the second scanning lens 217M is redirected by the second reflecting mirror 216M, passes through the light-transmitting part 219M, and reaches the outer peripheral surface of the photoreceptor drum 23M.

[0068] The cyan light beam emitted from the light source unit 210 is reflected by the rotating polygonal mirror 212 and deflected in the main scanning direction, then passes through the first scanning lens 213. The first scanning lens 213 corrects the direction of travel of the incident light beam so that the main scanning is performed at a constant speed on the photoreceptor drum 23C. The light beam after passing through the first scanning lens 213 is redirected by the first reflecting mirror 215C and guided to the second scanning lens 217C. The light beam passing through the second scanning lens 217C is redirected by the two second reflecting mirrors 216C, passes through the light-transmitting part 219C, and reaches the outer peripheral surface of the photoreceptor drum 23C.

[0069] The black light beam emitted from the light source unit 210 is reflected by the rotating polygonal mirror 212 and deflected in the main scanning direction, passing through the first scanning lens 213. The first scanning lens 213 corrects the direction of travel of the incident light beam so that the main scanning is performed at a constant speed on the photosensitive drum 23K. The light beam after passing through the first scanning lens 213 is guided to the second scanning lens 217K. The light beam passing through the second scanning lens 217K has its optical path changed by the first reflecting mirror 215K, passes through the light-transmitting part 219K, and reaches the outer peripheral surface of the photosensitive drum 23K.

[0070] Exposure unit 21 and developing units 20Y, 20M, 20C, and 20K are fixed to the frame of MFP100. The relative positions of exposure unit 21 and developing units 20Y, 20M, 20C, and 20K are determined by the relative positions of exposure unit 21 and the frame, as well as the relative positions of developing units 20Y, 20M, 20C, and 20K and the frame.

[0071] Figure 5 It is a 3D view of the exposure unit. Figure 6 This is a top view of the exposure unit. (Refer to...) Figure 5 as well as Figure 6 The frame 300 of the exposure unit 21 includes an open base 301 and a cover 303 covering the upper part of the base 301. The base 301 includes a bottom and a right side wall 225, a left side wall 226, a front side wall 227, and a rear side wall 228. The cover 303 is mounted on the base 301, thereby forming an internal space inside the frame 300. The internal space is surrounded by the base 301 and the cover 303 and is a closed space. Light-transmitting portions 219Y, 219M, 219C, and 219K are provided on the cover 303. The light-transmitting portions 219Y, 219M, 219C, and 219K are arranged on the cover 303 in a manner that extends along the main scanning direction. The frame 300 houses the light source unit 210, the polyhedral unit 211, the first scanning lens 213, the second scanning lenses 217Y, 217M, 217C, 217K, the first reflector 215Y, 215M, 215C, 215K, and the second reflector 216Y, 216M, 216C, 216K within its internal space.

[0072] A generally cylindrical first protrusion 221 is provided on the right side wall 225 of the base 301 of the exposure unit 21, protruding outward from the right side wall 225. A generally cylindrical second protrusion 224 is provided on the left side wall 226 of the base 301 of the exposure unit 21, protruding outward from the left side wall 226. Additionally, two generally cuboid third protrusions 223 are provided, protruding outward from the right side wall 225. The two third protrusions 223 are positioned to sandwich the first protrusion 221 in the Y direction. When the exposure unit 21 is mounted on the main frame, the first protrusion 221 and the two third protrusions 223 are respectively formed through openings in the main frame. Furthermore, when the exposure unit 21 is mounted on the main frame, the second protrusion 224 is also formed through an opening in the main frame. This determines the relative position of the exposure unit 21 and the main frame.

[0073] Return to Figure 4 A base substrate 400B is disposed on the front sidewall 227 of the frame 300 of the exposure unit 21. The base substrate 400B forms part of the front sidewall 227. A hole is formed through the front sidewall 227, and this hole is blocked by the base substrate 400B. Therefore, the internal space of the frame 300 remains closed. At least a portion of the base substrate 400B forms a closed wall that divides the internal space of the frame 300, i.e., part of the front sidewall 227. A base substrate 400A is disposed on the rear sidewall 228 of the frame 300. The base substrate 400A forms part of the rear sidewall 228. A hole is formed through the rear sidewall 228, and this hole is blocked by the base substrate 400A. Therefore, the internal space of the frame 300 remains closed. At least a portion of the base substrate 400A forms a closed wall that divides the internal space of the frame 300, i.e., part of the rear sidewall 228.

[0074] The base substrates 400A and 400B have a symmetrical structure in the XZ plane; therefore, base substrate 400A will be used as an example for explanation. Base substrate 400A is a printed circuit board. Base substrate 400A has an inner surface facing the interior space of the frame 300 and an outer surface facing the opposite side of the interior space. A photosensor 403 is disposed on the inner surface of base substrate 400A, and an adjustment member 401 is disposed on the outer surface. In this embodiment, only the adjustment member 401 is disposed on the outer surface of base substrate 400A. Therefore, the adjustment member 401 is easily replaceable.

[0075] The light beam, deflected in the main scanning direction by the polygon mirror 212, is guided by the first rear reflector 411A and the second rear reflector 412A to the photosensor 403 disposed on the base substrate 400A. The light beam, deflected in the main scanning direction by the polygon mirror 212, is guided by the first front reflector 411B and the second front reflector 412B to the photosensor 403 disposed on the base substrate 400B. The first rear reflector 411A and the first front reflector 411B are disposed outside the main scanning directions of the first reflectors 215Y, 215M, 215C, and 215K, respectively.

[0076] The first rear reflector 411A is arranged along the main scanning direction on the outer side of the upstream end of the first reflector 215K. The first front reflector 411B is arranged along the main scanning direction on the outer side of the downstream end of the first reflector 215K. Among the first reflectors 215Y, 215M, 215C, and 215K, the first reflector 215K is the longest at a distance from the polygon mirror 212.

[0077] The light beam reflected by the first rear reflector 411A and the second rear reflector 412A is incident on the photosensitive sensor 403 disposed on the base substrate 400A. The light detection signal output by the photosensitive sensor 403 disposed on the base substrate 400A is used as an SOS (Start of Scan) signal to synchronize the start of the main scan of the light beam deflected by the polygon mirror 212 in the main scanning direction.

[0078] The light beam reflected by the first front reflector 411B and the second front reflector 412B is incident on the photosensitive sensor 403 disposed on the base substrate 400B. The light detection signal output by the photosensitive sensor 403 disposed on the base substrate 400B is used as an EOS (End of Scan) signal to synchronize the end of the main scan of the light beam deflected by the polygon mirror 212 in the main scanning direction.

[0079] Figure 7 This is a diagram illustrating an example of the tendency of multifaceted mirrors to become contaminated. Figure 7 The upper part represents a top view of the polygon mirror 212, and the lower part represents a side view of the polygon mirror 212. (Refer to...) Figure 7 The polygon mirror 212 has a low profile, for example, a regular hexagonal prism shape, and has six reflecting surfaces forming the lateral faces of the hexagonal prism. Furthermore, the top view shape of the polygon mirror 212 is not limited to a regular hexagon; any polygon is acceptable. The reflecting surfaces are planar. The polygon mirror 212 rotates about its rotational symmetry axis. During the rotation of the polygon mirror 212, light incident from the light source unit 210 is deflected in the main scanning direction by each of the six reflecting surfaces. The beam deflected by one reflecting surface scans one line in the main scanning direction.

[0080] As the polygon mirror 212 rotates, airflow is generated around it. The polygon mirror 212 is in the shape of a regular hexagonal prism, and the airflow generated varies at different positions along the rotation direction of the mirror. In particular, during the rotation of the polygon mirror 212, vortices sometimes form on the front side of the mirror in the direction of rotation. Sometimes, due to these airflow vortices, dust suspended around the polygon mirror 212 adheres to the front side of the mirror. Therefore, the front side of the mirror tends to accumulate more dust compared to other parts.

[0081] As the contamination of the polygon mirror 212 changes over time, the reflectivity of the light beam decreases due to contamination of the reflective surface. As mentioned above, the contamination of the reflective surface progresses faster in the front-end portion than in other portions, therefore the degree of decrease in reflectivity is greater in the front-end portion than in other portions.

[0082] If the reflectivity of the front-end portion of the reflective surface of the polygon mirror 212 decreases excessively, the amount of light received by the photosensor 403 disposed on the base substrate 400A decreases, and an SOS signal cannot be obtained. Without an SOS signal, the start synchronization of the main scan of the light beam cannot be achieved. On the other hand, the reflectivity of the portion different from the front-end portion of the reflective surface of the polygon mirror 212 is greater than that of the front-end portion. Therefore, there is a sufficient amount of light in the light beam output by the exposure unit 21 to the developing units 20Y, 20M, 20C, and 20K. In this embodiment, the exposure unit 21 can output an SOS signal by increasing the sensitivity of the photosensor 403 when the front-end portion of the reflective surface of the polygon mirror 212 is contaminated.

[0083] Figure 8 This is a circuit diagram illustrating an example of a circuit formed on a substrate. (Refer to...) Figure 8 The circuit formed on the base substrate 400A includes an adjustment component 401, a light sensor 403, an amplifier 405, and a comparator 407. The light sensor 403 is a photoelectric conversion element. The light sensor 403 can be, for example, a photodiode or a charge-coupled device (CCD). The light sensor 403 can also be a phototransistor. Here, the case where the light sensor 403 uses a photodiode will be described as an example. The amplifier 405 is an amplifier that amplifies the current. The adjustment component 401 adjusts the photoelectric conversion gain in the light sensor 403. In this embodiment, the adjustment component 401 is a resistor that converts the current generated by the light received by the light sensor 403 into a voltage. The resistance value of the adjustment component 401 is predetermined.

[0084] An amplifier 405 and an adjustment component 401 are connected in series with a light sensor 403. When a light beam is incident on the light sensor 403, the light sensor 403 generates a current proportional to the amount of light from the incident beam. The amplifier 405 receives the current generated by the light sensor 403 as input. The amplifier 405 amplifies the current. The amplified current flows through the adjustment component 401. The adjustment component 401 converts the current output from the amplifier 405 into a voltage.

[0085] Comparator 407 is a comparator. A reference voltage Vref, which serves as the comparison reference, and a voltage converted from current via adjustment component 401 are input to comparator 407. Comparator 407 compares the input voltage converted from current via adjustment component 401 with the reference voltage Vref and outputs a digital signal. When the input voltage is above the reference voltage Vref, comparator 407 outputs a high-level digital signal H; when the input voltage is below the reference voltage Vref, it outputs a low-level digital signal L. Additionally, the input voltage converted from current via adjustment component 401 is output as an analog signal.

[0086] Here, the resistance value of the adjusting component 401 is set to R, the current flowing through the adjusting component 401 is set to Igain, and the voltage converted from the current through the adjusting component 401 is set to Vgain.

[0087] Vgain=Igain×R…(1)

[0088] Equation (1) above holds true. Vgain is equivalent to the analog output of the base substrate 400A. Hereinafter, the resistance value of the adjustment component 401 will be referred to as the gain resistance value R.

[0089] Figures 9-11 This is a diagram illustrating an example of analog output and digital signal from a base substrate. Figure 9 This is a diagram showing an example of the analog output and digital signal of the faceted mirror 212 in its initial, uncontaminated state. (Refer to...) Figure 9 In the analog output, the voltage difference between the state where no light beam is incident on the light sensor 403 and the state where the light beam is incident on the light sensor 403 is 2.0V. In the digital signal, the period of the high-level digital signal H is 480ns.

[0090] Figure 10 This is a diagram illustrating an example of the analog output and digital signal of a polygon mirror 212 with moderate contamination. (See reference...) Figure 10 In the analog output, the voltage difference between the state where the light beam is not incident on the light sensor 403 and the state where the light beam is incident on the light sensor 403 is 1.6V. In the digital signal, the period of the high-level digital signal H is 270ns.

[0091] Figure 11 This is a diagram illustrating an example of the significant contamination of the polygon mirror 212 in both analog and digital outputs. (See reference...) Figure 11 In the analog output, the voltage difference between the state where the light beam is not incident on the light sensor 403 and the state where the light beam is incident on the light sensor 403 is 1.0V. In the digital signal, the period of being high level is 190ns.

[0092] The peak value of the analog output decreases as contamination of the polygon mirror 212 progresses. The degree of contamination of the polygon mirror 212 can be detected based on the peak value. Furthermore, the pulse width of the digital signal shortens as contamination of the polygon mirror 212 progresses. The degree of contamination of the polygon mirror 212 can be detected based on the pulse width of the digital signal.

[0093] When the contamination of the polygon mirror 212 becomes extremely large, the peak value of the analog output decreases further. In this case, the analog output is not above the reference voltage Vref, and the digital signal is not a high-level digital signal H. As shown in equation (1) above, the analog output is determined by Igain and the gain resistor value R of the adjustment component 401. Therefore, by increasing the gain resistor value R of the adjustment component 401, Vgain can be increased. Thus, the analog output can be set to a value greater than the reference voltage Vref.

[0094] Figure 12 This is a diagram illustrating an example of a correspondence table. The table establishes a correspondence between the analog output Vgain of the base substrate 400A and the required gain resistance value R of the adjustment component 401. The required gain resistance value R of the adjustment component 401 represents the resistance value of the adjustment component 401 that should be replaced from the adjustment component 401 currently mounted on the base substrate 400A. The analog output Vgain shows the analog output relative to the gain resistance value R of the adjustment component 401 in its initial state. For analog output Vgain of 0 to 0.2 (V), no correspondence can be established for the gain resistance value R. This means that when the analog output Vgain is 0 to 0.2 (V) relative to the gain resistance value R in its initial state, the polygon mirror 212 needs to be replaced. Within the range of analog output Vgain of the base substrate 400A being above 0.2V and below 3.0V, the required gain resistance value R of the adjustment component 401 is determined in steps of 0.2V. For example, it is shown that when the analog output Vgain of the base substrate 400A is greater than 0.2 and less than 0.4V, the required gain resistance value R of the adjustment component 401 is 10.0kΩ.

[0095] Figure 13 This is a block diagram illustrating the general hardware structure of the MFP in this embodiment. (Refer to...) Figure 4The MFP100 includes a main circuit 110, a document reader 130, an automatic document feeder 120, an image forming unit 140, a paper feeder 150, and an operation panel 160. The operation panel 160 is the user interface.

[0096] The main circuit 110 includes a CPU 111, a communication interface (I / F) unit 112, a ROM 113, a RAM 114, an HDD 115, a fax unit 116, and an external storage device 117. The HDD 115 is a high-capacity storage device. A solid-state drive (SSD) can also be used instead of the HDD 115. The CPU 111 is connected to the automatic document feeder 120, the document reader 130, the image forming unit 140, the paper feeder 150, and the operation panel 160, controlling the entire MFP 100. The HDD 115 stores... Figure 12 The corresponding table is shown below.

[0097] The fax unit 116 is connected to the Public Switched Telephone Network (PSTN) and sends fax data to the PSTN. Additionally, the fax unit 116 receives fax data from the PSTN. The fax unit 116 stores the received fax data in the HDD 115 and converts it into printable data that can be printed in the image forming unit 140, then outputs it to the image forming unit 140. Thus, the image forming unit 140 forms an image on paper from the fax data received by the fax unit 116. Furthermore, the fax unit 116 converts the data stored in the HDD 115 into fax data and sends it to a fax device connected to the PSTN.

[0098] The communication I / F unit 112 is an interface for connecting the MFP100 to a network. The communication I / F unit 112 communicates with the PC200 connected to the network using communication protocols such as TCP (Transmission Control Protocol) or FTP (File Transfer Protocol).

[0099] ROM 113 stores the program executed by CPU 111 or the data required to execute the program. RAM 114 is used as the working area when CPU 111 executes the program. In addition, RAM 114 temporarily stores the read images continuously sent from the original document reading unit 130.

[0100] An operation panel 160 is disposed on the upper surface of the MFP100. The operation panel 160 includes a display unit 161 and an operation unit 163. The display unit 161 is, for example, a liquid crystal display (LCD) device, which displays user-instruction menus, information related to acquired image data, etc. Alternatively, instead of an LCD, any device that displays images, such as an organic EL display, may be used.

[0101] The operation unit 163 includes a touch panel 165 and a hard key unit 167. The touch panel 165 is capacitive. However, the touch panel 165 is not limited to capacitive methods; for example, it can use other methods such as resistive film, surface acoustic wave, infrared, or electromagnetic induction. The hard key unit 167 includes multiple hard keys. These hard keys are, for example, contact switches.

[0102] The external storage device 117 is controlled by the CPU 111 and is equipped with a CD-ROM 118. In this embodiment, an example of the CPU 111 executing a program stored in the ROM 113 will be described. Alternatively, the CPU 111 can also control the external storage device 117 to read a program for execution from the CD-ROM 118 and store the read program in the RAM 114 for execution.

[0103] Figure 14 This is a block diagram illustrating one example of the functions of the CPU 111 in the MFP of this embodiment. Figure 14 The functions shown are implemented by the CPU 111, which executes programs stored in ROM 113, HDD 115, or CD-ROM 118, through the CPU 111 of the MFP100. Additionally, Figure 14 The functions shown can also be implemented by the hardware available in the MFP100.

[0104] Reference Figure 14 The CPU 111 of the MFP100 includes a resistance value determination unit 51 and a resistance value display unit 53. The resistance value determination unit 51 controls the base substrates 400A and 400B, acquiring the digital signals and analog outputs from the base substrates 400A and 400B respectively. The resistance value determination unit 51 determines the gain resistance value based on the analog output of the base substrate 400A. Specifically, the resistance value determination unit 51 refers to a mapping table stored in the HDD 115 to determine the gain resistance value corresponding to the analog output of the base substrate 400A. The resistance value determination unit 51 outputs the gain resistance value to the resistance value display unit 53.

[0105] The resistance value display unit 53 notifies the user of the gain resistance value. For example, the resistance value display unit 53 displays the gain resistance value on the display unit 161. The user can observe the gain resistance value displayed on the display unit 161 and replace the adjustment member 401 disposed on the base substrate 400A with a resistor of the gain resistance value. The adjustment member 401 is disposed on the outside of the frame 300, so it is not necessary to remove the cover 303 from the base 301 of the frame 300. Therefore, it is easy to replace the adjustment member 401. In addition, it is not necessary to disassemble the exposure unit 21, so the position of the optical components inside the exposure unit 21 can remain unchanged.

[0106] Figure 15This is a flowchart illustrating an example of a maintenance assistance process. The maintenance assistance process is performed by the CPU 111 of the MFP100, which executes maintenance assistance programs stored in ROM 113, HDD 115, or CD-ROM 118. (See reference...) Figure 15 The CPU 111 of the MFP100 acquires the voltage applied to the adjustment component 401 (step S01) and causes the process to proceed to step S02. The CPU 111 determines the voltage applied to the adjustment component 401 based on the analog output of the base substrate 400A.

[0107] In step S02, the voltage is compared with a threshold Th1. The peak voltage of the analog output is compared with the threshold Th1. The threshold Th1 is a predetermined value stored in HDD115. If the peak voltage is below the threshold Th1, CPU111 causes the process to proceed to step S03; otherwise, the process returns to step S01.

[0108] In step S03, the gain resistor value R is determined, and the process proceeds to step S04. CPU 111 refers to the correspondence table stored in HDD 115 to determine the gain resistor value R corresponding to the peak voltage. In step S04, the gain resistor value R is displayed, and the process ends. CPU 111 displays the gain resistor value R on display unit 161.

[0109] <First Variation>

[0110] Figure 12 The corresponding table shows the relationship between the analog output Vgain of the base plate 400A and the required gain resistor value R of the adjustment component 401. The corresponding table can also establish a correspondence between the resistance multiplier of the currently installed adjustment component 401 and the analog output Vgain of the base plate 400A.

[0111] Figure 16This is a diagram illustrating an example of the correspondence table in the first modification. The correspondence table in the first modification establishes a correspondence between the analog output Vgain of the base substrate 400A and the multiplier of the resistance value relative to the currently mounted adjustment component 401. The analog output Vgain shows the analog output relative to the gain resistance value R of the currently mounted adjustment component 401. For analog output Vgain values ​​of 0 to 0.2 (V), a multiplier relative to the current resistance value cannot be established. This indicates that the polygon mirror 212 needs to be replaced. Within the range of 0.2V or higher and less than 3.0V for the analog output Vgain of the base substrate 400A, the multiplier relative to the resistance value of the currently mounted adjustment component 401 is determined in 0.2V increments. For example, when the analog output Vgain of the base substrate 400A is 0.2V or higher and less than 0.4V, there is a corresponding multiplier of 10.0 times the resistance value relative to the currently mounted adjustment component 401. The user can calculate the resistance value of the adjustment component 401 that should be replaced based on the resistance value and multiplier of the adjustment component 401 currently installed on the base substrate 400A. By using the correspondence table in the first modified example, the adjustment component 401 can be replaced multiple times.

[0112] <Second Variation>

[0113] The correspondence table can also establish a correspondence between the pulse width of the digital signal of the 400A base plate and the gain resistor value. Figure 17 This is a diagram illustrating an example of the correspondence table in the second variation. The correspondence table establishes a correspondence between the pulse width of the digital signal of the base substrate 400A and the gain resistor value R required by the adjustment member 401. The pulse width of the digital signal of the base substrate 400A shows the pulse width of the digital signal relative to the gain resistor value R in the initial state. For the pulse width of the digital signal of the base substrate 400A being 0 to 0.2 (μs), a correspondence cannot be established for the gain resistor value R. This means that when the pulse width of the digital signal is 0 to 0.2 (μs) relative to the gain resistor value R in the initial state, the polygon mirror 212 needs to be replaced. In the range where the pulse width of the digital signal of the base substrate 400A is 0.2 μs or more and less than 2.0 μs, the replacement gain resistor value R is determined in steps of 0.2 μs. For example, it is shown that when the pulse width of the digital signal of the base substrate 400A is 0.2 μs or more and less than 0.4 μs, a resistor with a gain resistor value R of 4.7 kΩ is replaced.

[0114] <Third Variation>

[0115] Figure 17The correspondence table in the second variation shown determines the relationship between the pulse width of the digital signal of the base substrate 400A and the required gain resistor value R of the adjustment component 401. The correspondence table in the third variation establishes a correspondence between the multiplier of the resistance value of the currently installed adjustment component 401 and the pulse width of the digital signal of the base substrate 400A.

[0116] Figure 18 This is a diagram illustrating an example of the correspondence table in the third modification. The correspondence table in the third modification establishes a correspondence between the pulse width of the digital signal of the base substrate 400A and the multiplication factor relative to the resistance value of the currently mounted adjustment component 401. The pulse width of the digital signal of the base substrate 400A shows the pulse width of the digital signal relative to the gain resistance value R of the currently mounted adjustment component 401. For a pulse width of 0 to 0.2 (μs) for the digital signal of the base substrate 400A, a multiplication factor relative to the current resistance value cannot be established. This indicates that the polygon mirror 212 needs to be replaced. Within the range where the pulse width of the digital signal of the base substrate 400A is 0.2 μs or more and less than 3.0 μs, the multiplication factor relative to the resistance value of the currently mounted adjustment component 401 is determined in steps of 0.2 μs. For example, when the pulse width of the digital signal of the base substrate 400A is 0.2 μs or more and less than 0.4 μs, there is a corresponding multiplication factor of 4.7 times relative to the resistance value of the currently mounted adjustment component 401. The user can calculate the resistance value of the adjustment component 401 that should be replaced based on the resistance value and multiplier of the adjustment component 401 currently installed on the base substrate 400A. By using the correspondence table in the third variation, the adjustment component 401 can be replaced multiple times.

[0117] <Fourth Variation>

[0118] The correspondence table can also establish a correspondence between the cumulative number of printed sheets and the gain resistor value. Figure 19 This is a diagram illustrating an example of the correspondence table in the fourth variation. The correspondence table establishes a relationship between the cumulative number of printed sheets and the required gain resistor value R for the adjustment component 401. For a printed sheet count of 0 to 50 (k sheets), the gain resistor value R corresponds to "no need to replace". This means that in the case of a cumulative printed sheet count of 0 to 50 (k sheets), the adjustment component 401 does not need to be replaced. For a printed sheet count of 450 to 500 (k sheets), the gain resistor value R corresponds to "no". This means that in the case of a cumulative printed sheet count of 450 to 500 (k sheets), the polygon mirror 212 needs to be replaced. In the range of a cumulative printed sheet count of 50k sheets or more but less than 500k sheets, the replacement gain resistor value is determined in steps of 50k sheets. For example, it shows that in the case of a cumulative printed sheet count of 50k sheets or more but less than 100k sheets, a resistor with a gain resistor value of 1.0kΩ is replaced.

[0119] <Fifth Variation>

[0120] Figure 19 The correspondence table in the fourth variation shows the relationship between the cumulative number of printed sheets and the gain resistance value R required by the adjustment component 401. The correspondence table in the fifth variation establishes a correspondence between the multiplier of the resistance value of the currently installed adjustment component 401 and the cumulative number of printed sheets.

[0121] Figure 20 This diagram illustrates an example of the correspondence table in the fifth modification. The correspondence table in the fifth modification establishes a correspondence between the cumulative number of printed sheets and the multiplier of the resistance value relative to the currently installed adjustment component 401. For a printed sheet count of 0 to 50 (k sheets), the multiplier relative to the current resistance value corresponds to a value where replacement is not required. This means that when the cumulative printed sheet count is 0 to 50 (k sheets), the adjustment component 401 does not need to be replaced. For a cumulative printed sheet count of 450 to 500 (k sheets), the multiplier relative to the current resistance value is not required. This means that the polygon mirror 212 needs to be replaced. Within the range of 50k sheets or more but less than 450k sheets, the multiplier relative to the resistance value of the currently installed adjustment component 401 is determined in steps of 50k sheets. For example, when the cumulative printed sheet count is 50k sheets or more but less than 100k sheets, the corresponding multiplier relative to the resistance value of the currently installed adjustment component 401 is 1.1 times. The user can calculate the resistance value of the adjustment component 401 that should be replaced based on the resistance value and multiplier of the adjustment component 401 currently installed on the base plate 400A. By using the correspondence table in the fifth variation, the adjustment component 401 can be replaced multiple times.

[0122] <Sixth Variation>

[0123] The correspondence table can also establish a relationship between the cumulative working time of the multifaceted mirror and the gain resistor value. Figure 21 This diagram illustrates an example of the correspondence table in the sixth modification. The correspondence table in the sixth modification establishes a correspondence between the cumulative operating time of the polygon mirror 212 and the required gain resistor value R for the adjustment component 401. For a cumulative operating time of 0 to 500 hours, the gain resistor value R corresponds to "no need to replace". This means that when the cumulative operating time is 0 hours or more but less than 500 hours, the adjustment component 401 does not need to be replaced. For a cumulative operating time of 4500 to 5000 hours, the gain resistor value R corresponds to "no". This means that when the cumulative operating time is 4500 hours or more but less than 5000 hours, the polygon mirror 212 needs to be replaced. Within the range of 500 hours or more but less than 5000 hours, the replacement gain resistor value is determined in 500-hour increments. For example, it shows that when the cumulative operating time is 500 hours or more but less than 1000 hours, a resistor with a gain resistor value of 1.0 kΩ is used.

[0124] <Seventh Variation>

[0125] Figure 21 The correspondence table in the sixth variation shows the relationship between the cumulative operating time and the required gain resistance value R of the adjustment component 401. The correspondence table in the seventh variation establishes a correspondence between the cumulative operating time and the multiplier of the resistance value of the currently installed adjustment component 401.

[0126] Figure 22 This is a diagram illustrating an example of the correspondence table in the seventh modification. The correspondence table in the seventh modification establishes a correspondence between accumulated operating time and a multiple of the resistance value of the currently installed adjustment component 401. For accumulated operating time of 0 to 500 hours, the multiple of the current resistance value corresponds to a situation where replacement is not required. This means that in the case of accumulated operating time of 0 to 500 hours, adjustment component 401 does not need to be replaced. For accumulated operating time of 4500 to 5000 hours, the multiple of the current resistance value corresponds to a situation where replacement is not required. This means that polygon mirror 212 needs to be replaced. In the range of accumulated operating time of 500 hours or more but less than 4500 hours, the multiple of the resistance value of the currently installed adjustment component 401 is determined in 500-hour increments. For example, in the case of accumulated operating time of 500 hours or more but less than 1000 hours, there is a corresponding multiple of 1.1 times the resistance value of the currently installed adjustment component 401. The user can calculate the resistance value of the adjustment component 401 that should be replaced based on the resistance value and multiplier of the adjustment component 401 currently installed on the base substrate 400A. By using the correspondence table in the seventh variation, the adjustment component 401 can be replaced multiple times.

[0127] <Eighth Variation>

[0128] In the above-described embodiments, the CPU 111 of the MFP100 determines the resistance value of the adjustment member 401 disposed on the base substrate 400A based on the analog output of the base substrate 400A. In the eighth variation, the CPU 111 of the MFP100 determines the resistance value of the adjustment member 401 disposed on the base substrate 400A based on the density difference of the toner image formed by the image forming unit 140.

[0129] Figure 23 This diagram illustrates an example of the functions of CPU 111 in the MFP100 of the eighth variant. (See reference...) Figure 23 The MFP100 in the eighth variant includes two concentration sensors 421 and 423. The CPU111 includes a resistance value determination unit 51A, a resistance value display unit 53, and a concentration detection unit 55.

[0130] Two density sensors 421 and 423 detect the density at both ends of the toner image formed by the developing unit 20Y in the main scanning direction. For example, the two density sensors 421 and 423 are positioned near the photoreceptor drum 23Y to detect the density of toner at both ends of the main scanning direction in the toner image formed on the photoreceptor drum 23Y. Alternatively, the two density sensors 421 and 423 can be positioned near any one of the photoreceptor drums 23Y, 23M, 23C, and 23K. In other words, the two density sensors 421 and 423 can detect the density of the toner image formed on any one of the photoreceptor drums 23Y, 23M, 23C, and 23K. Furthermore, the two density sensors 421 and 423 can also detect the density at both ends of the main scanning direction of the image formed on the paper. Here, the example is given where density sensor 421 detects the density upstream of the main scanning direction, and density sensor 423 detects the density downstream of the main scanning direction.

[0131] The concentration detection unit 55 controls the concentration sensors 421 and 423 to acquire the concentration detected by each sensor. The concentration detection unit 55 calculates the difference between the two concentrations and outputs the concentration difference to the resistance value determination unit 51A. The concentration is set to a value within the range of 0 to 255. The concentration in the portion of the photoreceptor drum 23Y that does not carry toner is 0, and the concentration in the portion of the photoreceptor drum 23Y that carries the maximum amount of toner is 255.

[0132] The resistance value determination unit 51A determines the gain resistance value R based on the concentration difference. Specifically, the resistance value determination unit 51A refers to the correspondence table stored in the eighth variant of HDD115 to determine the gain resistance value R of the adjustment member 401 disposed on the base substrate 400A. The resistance value determination unit 51A outputs the gain resistance value to the resistance value display unit 53.

[0133] The resistance value display unit 53 notifies the user of the gain resistance value R. The user can observe the gain resistance value displayed on the display unit 161 and replace the adjustment member 401 disposed on the base substrate 400A with a resistor of gain resistance value R. The adjustment member 401 is disposed on the outside of the frame 300, so it is not necessary to remove the cover 303 from the base 301 of the frame 300. Therefore, it is easy to replace the adjustment member 401. In addition, it is not necessary to disassemble the exposure unit 21, so the position of the optical components inside the exposure unit 21 can remain unchanged.

[0134] Figure 24This is a diagram illustrating an example of the correspondence table in the eighth variation. The correspondence table in the eighth variation establishes a correspondence between the concentration difference and the required gain resistance value R for the adjustment component 401. For concentration differences between 0 and 31, the corresponding gain resistance value R does not require replacement. This means that when the concentration difference is above 0 and below 31, the adjustment component 401 does not need to be replaced. In the range of concentration differences between 32 and 255, the replacement gain resistance value is determined in steps of 32. For example, it is shown that when the concentration difference is above 32 and below 63, a resistor with a gain resistance value of 1.0 kΩ is used.

[0135] Figure 25 This is a flowchart illustrating an example of the maintenance auxiliary processing flow in the eighth variation. (See also...) Figure 25 ,and Figure 15 The difference in the maintenance assistance process shown is that steps S01 and S02 are changed to steps S01A and S02A respectively. Other processes are the same as... Figure 15 The processing shown is the same, so it will not be repeated here.

[0136] The CPU 111 of the MFP100 acquires the concentration (step S01A), causing the process to proceed to step S02A. The CPU 111 acquires the concentrations output by concentration sensors 421 and 423 respectively. In step S02A, the concentration difference is compared with a threshold Th2. The threshold Th2 is a pre-determined value stored in HDD 115. If the concentration difference is below the threshold Th2, the CPU 111 causes the process to proceed to step S03; otherwise, the process returns to step S01A.

[0137] <Ninth Variation Example>

[0138] Figure 24 The correspondence table in the sixth variation shows the relationship between the concentration difference and the required gain resistance value R of the adjustment component 401. The correspondence table in the ninth variation establishes a correspondence between the concentration difference and the multiplier of the resistance value of the currently installed adjustment component 401.

[0139] Figure 26This diagram illustrates an example of the correspondence table in the ninth modification. The correspondence table in the ninth modification establishes a correspondence between the concentration difference and a multiple of the resistance value of the currently installed adjustment component 401. For concentration differences of 0 to 31, the multiple of the current resistance value corresponds to a situation where replacement is not required. This means that in the case of a concentration difference of 0 to 31, the adjustment component 401 does not need to be replaced. In the range of a concentration difference of 32 or more and 255 or less, the multiple of the resistance value of the currently installed adjustment component 401 is determined in steps of 32. For example, in the case of a concentration difference of 32 or more and 63 or less, there is a multiple of 1.1 times the resistance value of the currently installed adjustment component 401. The user can calculate the resistance value of the adjustment component 401 that should be replaced based on the resistance value and multiple of the adjustment component 401 currently installed on the base substrate 400A. By using the correspondence table in the ninth modification, the adjustment component 401 can be replaced multiple times.

[0140] <Other variations>

[0141] (1) The adjustment component 401 can also be configured as a DIP shape. The DIP shape is a shape having a main body and a connecting terminal, with the connecting terminal extending from the main body in one direction. Therefore, by moving the adjustment component 401 in one direction, it can be mounted and dismounted relative to the base plate 400A, thus making it easy to mount and dismount.

[0142] (2) The adjusting component 401 can also be a variable resistor whose resistance value can be changed. Since the resistance value of the adjusting component 401 can be changed, it is not necessary to replace the adjusting component 401, so the operation of changing the resistance value of the adjusting component 401 is easy.

[0143] (3) The adjustment component 401 may also have multiple resistors with different resistance values ​​and a switching unit that allows switching to any one of the multiple resistors. The switching unit allows switching to any one of the multiple resistors. Therefore, the user can easily switch the resistance value by operating the switching unit to select any one of the multiple resistors.

[0144] (4) In this embodiment, only the adjustment member 401 is disposed on the outer surface of the base substrate 400A. Alternatively, other members besides the adjustment member 401 may be disposed on the outer surface of the base substrate 400A. In this case, it is preferable that the size of the adjustment member 401 is larger than the size of the other members. In this case, the adjustment member 401 can be easily identified from among the multiple members disposed on the outer surface of the base substrate 400A.

[0145] <Summary of Implementation Methods>

[0146] (Item 1) An optical writing device, comprising:

[0147] Multifaceted mirrors deflect light beams;

[0148] A light sensor is positioned at the point where the light beam, after being deflected by the aforementioned polygonal mirror, is incident;

[0149] A housing housing that houses the aforementioned polygonal mirrors within its internal space; and

[0150] The adjustment component adjusts the photoelectric conversion gain relative to the incident light directed to the aforementioned optical sensor.

[0151] The aforementioned adjustment components are disposed on the outside of the aforementioned housing.

[0152] According to this aspect, an adjustment component for adjusting the photoelectric conversion gain of the incident light relative to the position of the light sensor disposed at the point of incidence of the light beam deflected by the polygonal mirror is disposed outside the housing housing containing the polygonal mirror within the internal space. Therefore, with the polygonal mirror housed within the internal space of the housing housing, the photoelectric conversion gain of the adjustment component can be adjusted. As a result, an easily maintainable optical writing device can be provided.

[0153] (Item 2) The optical writing device according to Item 1, wherein,

[0154] The aforementioned housing encloses the aforementioned internal space.

[0155] According to this aspect, the internal space is enclosed by the housing, so the photoelectric conversion gain can be adjusted without opening the internal space of the housing to the outside.

[0156] (Item 3) The optical writing device according to Item 2, wherein,

[0157] It also includes a base component for arranging the aforementioned adjustment components.

[0158] At least a portion of the aforementioned base component constitutes part of a closed wall that divides the aforementioned internal space of the aforementioned housing.

[0159] According to this aspect, at least a portion of the base component equipped with the adjustment member constitutes part of the enclosing wall of the housing, thus enabling the housing component to be enclosed and the adjustment member to be disposed outside the housing.

[0160] (Item 4) The optical writing device according to Item 3, wherein,

[0161] The aforementioned base component has an inner surface facing the internal space of the aforementioned housing and an outer surface facing the side opposite to the aforementioned internal space.

[0162] The aforementioned optical sensor is disposed on the aforementioned inner surface.

[0163] The aforementioned adjustment component is disposed on the aforementioned outer surface.

[0164] According to this aspect, the light sensor is disposed on the inner surface and the adjustment component is disposed on the outer surface. Therefore, the photoelectric conversion gain of the light sensor can be adjusted while the housing component is closed.

[0165] (Item 5) The optical writing device according to Item 4, wherein,

[0166] The aforementioned outer surface is only fitted with the aforementioned adjustment components.

[0167] In this respect, no parts different from the adjustment parts are installed on the outer surface, so that the user can easily access the adjustment parts.

[0168] (Item 6) The optical writing device according to Item 4, wherein,

[0169] The dimensions of the aforementioned adjustment component are larger than the dimensions of other components mounted on the aforementioned outer surface.

[0170] In this respect, the size of the adjustment component is larger than that of other components mounted on the outer surface, so that the user can easily distinguish the adjustment component from the other components.

[0171] (Item 7) The optical writing device according to any one of items 3 to 6, wherein,

[0172] The aforementioned adjustment components are installed on the aforementioned base components in a detachable manner.

[0173] In this respect, the adjusting component can be mounted and dismounted relative to the base component, thus making it easy to replace the adjusting component.

[0174] (Item 8) The optical writing device according to any one of items 2 to 7, wherein,

[0175] The aforementioned housing also houses the aforementioned optical sensor, the motor that drives the aforementioned polygon mirror, the light source, the lens, and the reflector within the aforementioned internal space.

[0176] According to this aspect, a light sensor, a motor, a light source, a lens, and a reflector are housed within the internal space of the housing. The photoelectric conversion gain can be adjusted without disassembling the housing, thus suppressing changes in the optical path that occur with the disassembly of the housing.

[0177] (Item 9) The optical writing device according to any one of items 2 to 8, wherein,

[0178] The aforementioned housing is provided with a light-transmitting section that allows light to pass through.

[0179] Based on this, a light-transmitting part is provided in the housing, so that light can be output to the outside.

[0180] (Item 10) The optical writing device according to any one of items 1 to 9, wherein,

[0181] The aforementioned adjustment component is a resistor.

[0182] Based on this, the adjustment component is a resistor, thus the photoelectric conversion gain can be easily adjusted.

[0183] (Item 11) The optical writing device according to Item 10, wherein,

[0184] The aforementioned adjustment component is a variable resistor.

[0185] In this respect, the adjustment component is a variable resistor, so the photoelectric conversion gain can be adjusted without replacing the adjustment component.

[0186] (Item 12) The optical writing device according to any one of items 1 to 11, wherein,

[0187] The aforementioned adjustment component is in DIP shape.

[0188] In this respect, the adjustment part is DIP shaped, so it is easy to replace.

[0189] (Item 13) The optical writing device according to any one of items 1 to 12, wherein,

[0190] The aforementioned adjustment component includes multiple resistors with different resistance values ​​and a switching unit for switching any one of the multiple resistors.

[0191] Based on this, by switching from a number of resistors with different resistance values ​​to any one of them, the photoelectric conversion gain can be easily adjusted.

[0192] (Item 14) The optical writing device according to any one of items 1 to 13, wherein,

[0193] There are multiple optical sensors mentioned above.

[0194] Based on this, there are multiple light sensors, thus enabling the detection of light beams deflected at multiple positions on the multifaceted mirror.

[0195] (Item 15) An image forming apparatus, comprising:

[0196] The optical writing device described in any one of items 1 to 14;

[0197] The resistance value determining unit determines the resistance value of the aforementioned adjusting component; and

[0198] The display control unit displays the resistance value determined by the aforementioned resistance value determination unit.

[0199] Based on this, the resistance value of the adjustment component is determined and displayed, thus enabling the provision of an image forming apparatus that is easy to maintain.

[0200] (Item 16) The image forming apparatus according to Item 15, wherein,

[0201] The resistance value determination unit determines the resistance value of the adjustment component based on the output voltage value or output voltage width of the optical sensor.

[0202] Based on this, the resistance value of the adjustment component is determined by the output voltage value or the output voltage width of the optical sensor, thus enabling the determination of the resistance value corresponding to the contamination of the multifaceted mirror.

[0203] (Item 17) The image forming apparatus according to item 15 or 16, wherein,

[0204] It also includes an image forming unit that forms an image on the recording medium.

[0205] The resistance value determination unit determines the resistance value of the adjustment component based on the cumulative number of images formed on the recording medium by the image forming unit.

[0206] Based on this aspect, the resistance value of the adjustment component is determined according to the cumulative number of images on the recording medium, thus making it easy to determine the resistance value corresponding to the contamination of the multifaceted mirror.

[0207] (Item 18) The image forming apparatus according to any one of items 15 to 17, wherein,

[0208] The resistance value determination unit determines the resistance value of the adjustment component based on the cumulative working time of the multifaceted mirror.

[0209] Based on this, the resistance value of the adjustment component is determined according to the cumulative working time of the multifaceted mirror, thus making it easy to determine the resistance value corresponding to the contamination of the multifaceted mirror.

[0210] (Item 19) The image forming apparatus according to any one of items 15 to 18, wherein,

[0211] It also has:

[0212] The image forming unit forms an image on the recording medium; and

[0213] The concentration detection unit detects the concentration of the image formed by the image forming unit described above.

[0214] The resistance value determination unit determines the resistance value of the adjustment component based on the concentration detected by the concentration detection unit.

[0215] Based on this aspect, the resistance value of the adjustment component is determined according to the density of the image formed on the recording medium, thus making it easy to determine the resistance value corresponding to the contamination of the multifaceted mirror.

[0216] (Item 20) A maintenance assistance method, which is a maintenance assistance method performed by the optical writing device described in any one of items 1 to 14, wherein,

[0217] The above methods include:

[0218] The resistance value determination step determines the resistance value of the aforementioned adjustment component; and

[0219] The display control steps show the resistance value determined in the resistance value determination steps described above.

[0220] Based on this, easy-to-maintain maintenance assistance methods can be provided.

[0221] (Item 21) A maintenance assistance program, which is executed by a computer of the optical writing device described in any one of control items 1 to 14, wherein the computer is made to execute:

[0222] The resistance value determination step determines the resistance value of the aforementioned adjustment component; and

[0223] The display control steps show the resistance value determined in the resistance value determination steps described above.

[0224] Based on this, easy-to-maintain maintenance assistance programs can be provided.

[0225] (Item 22) The optical writing device according to any one of items 1 to 14, wherein,

[0226] The position where the aforementioned optical sensor is configured is the position illuminated by the upstream end of the beam in the main scanning direction of the beam deflected by the aforementioned polygonal mirror in the main scanning direction.

[0227] According to this aspect, a light sensor is positioned at the upstream end of the beam in the main scanning direction of the beam deflected by the polygon mirror. Regarding the amount of dust adhering to the reflective surface of the polygon mirror, the upstream end of the reflective surface in the main scanning direction has more dust than other parts. Therefore, it is possible to detect the amount of light deflected by the portion of the beam that is more heavily contaminated by the polygon mirror.

[0228] The embodiments disclosed herein should be considered illustrative in all respects and not intended to limit the invention. The scope of the invention is defined not by the foregoing description but by the claims, and is intended to include all equivalents of the claims and all modifications within the scope.

Claims

1. An optical writing device, wherein, have: Multifaceted mirrors deflect light beams; A light sensor is positioned at the incident point of the light beam after it has been deflected by the multifaceted mirror; A housing housing that houses the polygonal mirror within its internal space; and The adjustment component adjusts the photoelectric conversion gain relative to the incident light directed to the optical sensor. The adjustment component is disposed outside the housing.

2. The optical writing device according to claim 1, wherein, The housing encloses the internal space.

3. The optical writing device according to claim 2, wherein, It also includes a base component for mounting the adjustment component. At least a portion of the base component forms part of a closed wall that divides the interior space of the housing.

4. The optical writing device according to claim 3, wherein, The base component has an inner surface facing the interior space of the housing and an outer surface facing the side opposite to the interior space. The optical sensor is disposed on the inner surface. The adjustment component is disposed on the outer surface.

5. The optical writing device according to claim 4, wherein, Only the adjustment component is installed on the outer surface.

6. The optical writing device according to claim 4, wherein, The size of the adjustment component is larger than the size of other components mounted on the outer surface.

7. The optical writing apparatus according to any one of claims 3 to 6, wherein, The adjustment component is installed on the base component in a detachable manner.

8. The optical writing apparatus according to any one of claims 2 to 7, wherein, The housing also houses the light sensor, the motor that drives the polygon mirror, the light source, the lens, and the reflector in the internal space.

9. The optical writing apparatus according to any one of claims 2 to 8, wherein, The housing is provided with a light-transmitting section that allows light to pass through.

10. The optical writing apparatus according to any one of claims 1 to 9, wherein, The adjusting component is a resistor.

11. The optical writing apparatus according to claim 10, wherein, The adjusting component is a variable resistor.

12. The optical writing apparatus according to any one of claims 1 to 11, wherein, The adjustment component is DIP shaped.

13. The optical writing apparatus according to any one of claims 1 to 12, wherein, The adjustment component includes multiple resistors with different resistance values ​​and a switching part for switching any one of the multiple resistors.

14. The optical writing apparatus according to any one of claims 1 to 13, wherein, There are multiple optical sensors.

15. An image forming apparatus, wherein, have: The optical writing apparatus as described in any one of claims 1 to 14; The resistance value determining unit determines the resistance value of the adjusting component; and The display control unit displays the resistance value determined by the resistance value determination unit.

16. The image forming apparatus according to claim 15, wherein, The resistance value determination unit determines the resistance value of the adjustment component based on the output voltage value or output voltage width of the optical sensor.

17. The image forming apparatus according to claim 15 or 16, wherein, It also includes an image forming unit that forms an image on a recording medium. The resistance value determination unit determines the resistance value of the adjustment member based on the cumulative number of images formed on the recording medium by the image forming unit.

18. The image forming apparatus according to any one of claims 15 to 17, wherein, The resistance value determination unit determines the resistance value of the adjustment component based on the cumulative working time of the multifaceted mirror.

19. The image forming apparatus according to any one of claims 15 to 18, wherein, It also has: The image forming unit forms an image on the recording medium; and The concentration detection unit detects the concentration of the image formed by the image forming unit. The resistance value determination unit determines the resistance value of the adjustment component based on the concentration detected by the concentration detection unit.

20. A maintenance assistance method, performed by the optical writing device according to any one of claims 1 to 14, wherein, The maintenance assistance method includes: The resistance value determination step determines the resistance value of the adjustment component; and The display control steps show the resistance value determined in the resistance value determination step.

21. A computer program product executed by a computer controlling the optical writing device described in any one of claims 1 to 14, wherein, The computer program product causes the computer to execute: The resistance value determination step determines the resistance value of the adjustment component; and The display control steps show the resistance value determined in the resistance value determination step.

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