Method for evaluating scanning exposure device and scanning exposure device

Abstract

To evaluate the state of deterioration of a scanning exposure device comprising a polygon mirror without complicating the configuration of the device.SOLUTION: Provided is a method for evaluating an exposure unit 500 in an image forming apparatus 10 comprising: the exposure unit 500 having an optical sensor 560 detecting light deflected by a polygon mirror 530 and outputting a detection signal when the quantity of incident light exceeds a threshold; an electrophotographic processing unit 600; and a fixing unit 700, the method including: rotating the polygon mirror 530 in S104; acquiring the detection signal from the optical sensor 560 in S114, S116, and S118; gradually changing optical output from a semiconductor laser 510 in S130, S132, S134, S136, S140, and S142; and acquiring a first optical output value of the semiconductor laser 510 when the detection signal from the optical sensor 560 is obtained at the first optical output value and the detection signal from the optical sensor 560 is not obtained at a second optical output value of the semiconductor laser 510 smaller by α than the first optical output value in S144.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an evaluation method for a scanning exposure apparatus equipped with a polygon mirror that deflects light from a semiconductor laser, and to the scanning exposure apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, as described in, for example, Patent Document 1, a method for predicting the remaining life of a polygon mirror by measuring the output level of an optical sensor that detects a light beam deflected by the polygon mirror has been known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-184806 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the image forming device described in Patent Document 1, the output level of the optical sensor is periodically acquired at a predetermined time interval, the rate of change over time is calculated based on the measured value obtained in the current measurement and the measured value obtained in the previous measurement, and the remaining life of the polygon mirror is predicted according to the calculated rate of change over time. Therefore, a new configuration such as an A / D converter that is not necessary for the original printing operation of the image forming device is required, which causes a problem of a complicated device configuration and an increase in manufacturing costs.

[0005] An object of the present invention is to provide a scanning exposure apparatus and an evaluation method thereof that can evaluate the deterioration state of a scanning exposure apparatus equipped with a polygon mirror without complicating the apparatus configuration. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a method for evaluating a scanning exposure device of the present invention is a method for evaluating a scanning exposure device in an image forming apparatus including a scanning exposure device having a light source having a semiconductor laser, a polygon mirror that deflects light from the semiconductor laser, and an optical sensor that detects the light deflected by the polygon mirror and is configured to output a detection signal when the amount of incident light exceeds a predetermined threshold, an electrophotographic process unit that has a photosensitive member exposed by the scanning exposure device and forms a toner image on a transfer medium, and a fixation unit that fixes the toner image to the transfer medium, the method including a first step of rotating the polygon mirror, a second step of outputting light of the semiconductor laser and acquiring a detection signal from the optical sensor, a third step of changing the optical output of the semiconductor laser and determining whether or not a detection signal is obtained from the optical sensor, and a fourth step of acquiring at least one of the first optical output value or the second optical output value when the detection signal from the optical sensor is obtained at a first optical output value of the semiconductor laser and the detection signal from the optical sensor is no longer obtained at a second optical output value of the semiconductor laser that is smaller than the first optical output value by a predetermined deviation.

[0007] In the scanning exposure apparatus according to the evaluation method of the present invention, the optical sensor is configured to output a detection signal when the amount of incident light exceeds a predetermined threshold. In the evaluation method of the scanning exposure apparatus according to the present invention, a first step, a second step, a third step, and a fourth step are executed. In the first step, the polygon mirror is rotated, and in the second step, light from the semiconductor laser is output and a detection signal from the optical sensor is obtained. In the third step, the optical output of the semiconductor laser is changed to determine whether or not a detection signal is obtained from the optical sensor. In the fourth step, when a detection signal is obtained from the optical sensor at a first optical output value of the semiconductor laser and a detection signal is no longer obtained from the optical sensor at a second optical output value smaller than the first optical output value by a predetermined deviation, at least one of the first optical output value and the second optical output value is obtained. When the output value is lowered by a predetermined deviation from the first optical output value and a detection signal cannot be obtained at the second optical output value, the first optical output value is the lower limit output at which a detection signal can be obtained from the optical sensor. That is, since the larger the first optical output value, the lower the reflectance of the polygon mirror, the deterioration state of the scanning exposure device can be evaluated based on the magnitude of this first optical output value. This is because the larger the first optical output value, the more advanced the deterioration. Note that evaluation can also be performed using the first optical output value and / or the second optical output value. As a result, the deterioration state of the scanning exposure device, mainly caused by dirt on the polygon mirror, can be evaluated without disassembling the device. In particular, the decrease in reflectance due to dirt on the part of the polygon mirror that reflects toward the optical sensor, which is the part that is most susceptible to dirt, can be evaluated. As described above, the evaluation method for a scanning exposure device of the present invention does not require an A / D converter or other components in a sensor output detection circuit, which are unnecessary components of an image forming device, thereby preventing the device configuration from becoming complicated and costs from increasing.

[0008] In addition, in the second step, the optical output of the semiconductor laser is used as a reference value and a detection signal is obtained from the optical sensor, and in the third step, the optical output of the semiconductor laser is gradually reduced from the reference value by the specified deviation and it is determined whether a detection signal is obtained from the optical sensor, and in the fourth step, the first optical output value one step before the second optical output value at which the detection signal from the optical sensor is no longer obtained after the gradually reduced value is obtained.

[0009] In the evaluation method for a scanning exposure device of the present invention, in a second step, a detection signal is obtained from an optical sensor with the optical output of the semiconductor laser set to a predetermined reference value. In a third step, the optical output of the semiconductor laser is gradually reduced by a predetermined deviation from the reference value, and it is determined whether or not a detection signal is obtained from the optical sensor. In a fourth step, a first optical output value that is one step before the second optical output value of the semiconductor laser when the detection signal from the optical sensor is no longer obtained is obtained. After the optical output of the semiconductor laser is set to a reference value and a detection signal of the optical sensor is obtained, the optical output is gradually lowered until a detection signal is no longer obtained at the second optical output value. The deterioration state of the scanning exposure device can be evaluated using the first optical output value at the immediately preceding stage. By simply gradually lowering the optical output from the reference value in stages, the deterioration state can be evaluated smoothly and quickly.

[0010] Further, the method may include a fifth step of forming and printing a predetermined pattern image on the transfer medium, the pattern image having a first fill pattern extending in the main scanning direction and a second fill pattern arranged with a gap in the main scanning direction from the first fill pattern, and evaluating the scanning exposure device based on the printing density of the gap.

[0011] In the evaluation method of the scanning exposure device of the present invention, in the fifth step, a predetermined pattern image is formed and printed on a transfer medium. The pattern image includes a first fill pattern extending in the main scanning direction and a second fill pattern arranged with a gap in the main scanning direction from the first fill pattern. In this way, when the polygon mirror is dirty, the printing in the gap becomes darker, and the deterioration state of the scanning exposure device caused by the dirt on the polygon mirror can be evaluated based on this. In particular, the diffuse reflection of light caused by the dirt on the part of the polygon mirror that is actually used for printing can be evaluated.

[0012] The predetermined pattern image may be arranged in a plurality of patterns in the sub-scanning direction while being shifted in the main scanning direction.

[0013] In the method for evaluating a scanning exposure apparatus of the present invention, a plurality of predetermined pattern images are arranged in the sub-scanning direction while being shifted in the main scanning direction, so that contamination in a plurality of ranges in the reflection area of ​​the polygon mirror can be evaluated.

[0014] The background of the predetermined pattern image may be filled with a halftone color of the predetermined pattern image.

[0015] In the evaluation method of the scanning exposure device of the present invention, the background of a predetermined pattern image is filled with a halftone color of the predetermined pattern image, so that when a gap is exposed due to diffuse reflection caused by dirt on the polygon mirror, it is easy to compare the print density of the background filled with a halftone color with the print density of the gap, making it easy to detect the dirt.

[0016] The image forming device may also be configured to perform evaluation of the scanning exposure device by executing the first step, the second step, the third step, and the fourth step each time the number of printed sheets exceeds a predetermined number.

[0017] Since the progress of contamination of the polygon mirror differs depending on the environment in which the device is installed, such as whether the air is dirty or not, the degree of deterioration of the scanning exposure device also differs depending on the environment. In the method for evaluating a scanning exposure device of the present invention, the first step, the second step, the third step, and the fourth step are performed every time a predetermined number of printed sheets are counted, thereby making it possible to accurately evaluate the degree of deterioration of the scanning exposure device.

[0018] In addition, the image forming apparatus may have a storage device built into the image forming apparatus, and may further have a sixth step of storing at least one of the first light output value or the second light output value obtained in the fourth step in the storage device.

[0019] In the evaluation method of the scanning exposure apparatus of the present invention, in the sixth step, at least one of the first optical output value and the second optical output value obtained in the fourth step is stored in a storage device built into the apparatus, so that the degree of deterioration can be evaluated from the history of the stored contents.

[0020] The method may further include a seventh step of storing at least one of the first light output value and the second light output value obtained in the fourth step in an external terminal connected to the image forming apparatus.

[0021] In the evaluation method of the scanning exposure apparatus of the present invention, in the seventh step, at least one of the first optical output value and the second optical output value acquired in the fourth step is stored in an external terminal such as a PC, a smartphone, or a server connected to the apparatus. As a result, evaluation of the scanning exposure apparatus can be performed by the external terminal.

[0022] and an eighth step of determining whether or not an evaluation execution request has been received from the external terminal. and when an evaluation execution request is received from the external terminal, the first step, the second step, the third step, and the fourth step may be executed.

[0023] In the method for evaluating a scanning exposure apparatus according to the present invention, in step 8, it is determined whether or not there has been a request to execute evaluation from an external terminal, and if there has been a request to execute evaluation, steps 1, 2, 3, and 4 are executed. As a result, the deterioration state can be obtained whenever desired by a management system or the like.

[0024] In order to achieve the above-mentioned object, the scanning exposure apparatus of the present invention has a light source having a semiconductor laser, a polygon mirror that deflects light from the semiconductor laser, an optical sensor that detects the light deflected by the polygon mirror and is configured to output a detection signal when the amount of incident light exceeds a predetermined threshold, and a control unit, wherein the control unit executes a first process of rotating the polygon mirror, a second process of outputting light of the semiconductor laser and acquiring a detection signal from the optical sensor, a third process of changing the optical output of the semiconductor laser and determining whether a detection signal can be obtained from the optical sensor, and a fourth process of acquiring at least one of the first optical output value or the second optical output value when the detection signal from the optical sensor is obtained at a first optical output value of the semiconductor laser and the detection signal from the optical sensor is no longer obtained at a second optical output value of the semiconductor laser that is smaller than the first optical output value by a predetermined deviation. Effect of the Invention

[0025] According to the present invention, it is possible to evaluate the deterioration state of a scanning exposure apparatus equipped with a polygon mirror without complicating the apparatus configuration. [Brief description of the drawings]

[0026] [Figure 1] 1 is a schematic cross-sectional side view illustrating an overall configuration of an image forming apparatus 10 according to an embodiment of the present invention. [Diagram 2] 5 is a schematic plan view showing a schematic configuration of a scanning unit 505. FIG. [Diagram 3] 5 is a block diagram showing a configuration relating to signal transmission / reception between an ASIC 575 and a motor driver 574 in the exposure section 500 and each section of a scanning unit 505. FIG. [Figure 4] 13 is a circuit diagram showing a detailed configuration of an optical sensor 560. FIG. [Diagram 5] 10 is a flowchart showing a process performed by a control unit 570 to execute a method for evaluating an exposure unit 500 according to an embodiment of the present invention. [Figure 6] 11 is a flowchart showing a detailed procedure of S100. [Figure 7] 1 is an external view of a transfer medium, showing an example of a pattern image printed by an image forming apparatus, used when performing an evaluation method for an exposure unit 500 according to an embodiment of the present invention. FIG. [Figure 8] 1 is an external view of a transfer medium, showing an example of a pattern image printed by an image forming apparatus, used when performing an evaluation method of an exposure unit 500 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] An embodiment of the present invention will be described with reference to the drawings.

[0028] <General Configuration of Image Forming Apparatus 10> 1, the image forming apparatus 10 is an electrophotographic image forming apparatus, and includes a housing 100. The housing 100 includes a transfer medium supply unit 200, an image forming unit 300, a support frame 101 that supports a discharge roller 400, and an exterior 102 that covers the support frame 101.

[0029] The transfer medium supply section 200 has a tray 210 and a transport roller 230. The transfer medium W accommodated in the tray 210 is transported by the transport roller 230 and sent to the image forming section 300 at a predetermined timing.

[0030] The image forming section 300 includes an exposure section 500 as an example of a scanning exposure device, an electrophotographic process section 600 , and a fixing unit 700 .

[0031] The exposure unit 500 is capable of emitting laser light L. The exposure unit 500 is capable of forming a line-shaped electrostatic latent image on the photoconductor 610 by irradiating and exposing the photoconductor 610 to the laser light L. The configuration of the exposure unit 500 will be described in detail later.

[0032] The electrophotographic process unit 600 includes a photoconductor 610, a charging unit 620, a developing unit 630, and a transfer roller 640. The charging unit 620 uniformly charges the surface of the photoconductor 610. When the surface of the photoconductor 610 uniformly charged by the charging unit 620 is irradiated with the laser light L from the exposure unit 500 described above, an electrostatic latent image is formed on the surface of the photoconductor 610. The developing unit 630 develops the electrostatic latent image formed on the surface of the photoconductor 610 by supplying a developer. As a result, a developer image, for example, a toner image, is formed on the surface of the photoconductor 610. The transfer roller 640 is disposed to face the photoconductor 610, and transfers the toner image formed on the surface of the photoconductor 610 to a transfer medium W conveyed by the transfer medium supply unit 200.

[0033] The fixing unit 700 uses heat to fix the toner image onto the transfer medium W. Thereafter, the transfer medium W is discharged by the discharge rollers 400 through the discharge port 110 onto the discharge tray 120.

[0034] <Exposure unit 500> As shown in FIG. 2, the exposure section 500 includes a scanning unit 505 and a control section 570. The control unit 570 has a substrate 572, an ASIC (application specific integrated circuit) 575 which is an application specific integrated circuit mounted on the substrate 572, and a motor driver 574. The motor driver 574 may be provided on the scanning unit 505 side. The control unit 570, in this example, the substrate 572 thereof is supported by the support frame 101.

[0035] <Detailed configuration of scanning unit 505> The scanning unit 505 has a light source, in this example, a semiconductor laser 510, a first lens unit 515, a polygon mirror 530, a polygon motor 532, a second lens unit 520, and an optical sensor 560 as an example of an optical sensor. The scanning unit 505 is supported by a support frame 101. The LD driver 580 will be described later.

[0036] <Semiconductor laser 510> The semiconductor laser 510 includes an optical sensor 590 and a base portion 592 .

[0037] <Light emitting part LD> A light emitting unit LD is provided on the semiconductor substrate of the base portion 592. The light emitting unit LD emits laser light L from an end face of the semiconductor substrate, and emits back laser light LA ​​from an end face of the semiconductor substrate opposite to the end face from which the laser light L is emitted.

[0038] <Optical Sensor 590> The optical sensor 590 is, for example, a photodiode, and receives the back laser light LA ​​from the light emitting section LD.

[0039] <First lens unit 515, polygon mirror 530, second lens unit 520> The first lens unit 515 is configured by, for example, a collimator lens. The first lens unit 515 converts the laser light L from the light emitting unit LD into a beam and irradiates the beam toward the polygon mirror 530.

[0040] The polygon mirror 530 is, for example, a rotary polygon mirror having six reflecting surfaces 531 arranged so as to form the side surfaces of a regular hexagonal prism. The polygon mirror 530 is rotationally driven by a polygon motor 532, and deflects the laser light L from the semiconductor laser 510. Specifically, the polygon mirror 530 deflects and scans the beam incident from the first lens unit 515.

[0041] The second lens unit 520 is a scanning optical system, and is formed of, for example, an fθ lens. The second lens unit 520 focuses the beam of the laser light L, which is irradiated from the first lens unit 515 and reflected by the reflecting surface 531 of the polygon mirror 530, on the surface of the photoconductor 610.

[0042] When the polygon mirror 530 rotates in accordance with the rotation of the polygon motor 532, the angle of the reflecting surface 531 with respect to the irradiation direction of the laser light L from the first lens unit 515 changes periodically. As a result, the laser light L is periodically deflected by the reflecting surface 531, and a scanning line by the beam of the laser light L is formed on the surface of the photoconductor 610.

[0043] <Optical sensor 560> The optical sensor 560 detects the light deflected by the polygon mirror 530. Specifically, the optical sensor 560 receives the beam of laser light L that is incident from the first lens portion 515 and reflected by the reflecting surface 531 when the angle of the reflecting surface 531 is at a specific angle.

[0044] The semiconductor laser 510, the first lens unit 515, the polygon mirror 530, the polygon motor 532, the second lens unit 520, and the optical sensor 560 are held by an optical frame 506 together with an LD driver 580. The optical frame 506 is supported by the support frame 101 described above.

[0045] <Circuit configuration of exposure unit 500> FIG. 3 shows a configuration relating to signal transmission and reception between the ASIC 575 and the motor driver 574 in the exposure section 500 and each section of the scanning unit 505.

[0046] <LDドライバ580> The LD driver 580 is configured to be capable of outputting a signal for switching the light emitting unit LD of the semiconductor laser 510 between an emitting state and an extinguished state based on control by a video signal from the ASIC 575. Specifically, the LD driver switches the light emitting unit LD between an emitting state and an extinguished state based on a video signal by a supply voltage from a power supply line (not shown).

[0047] <Light amount adjustment section 582> The LD driver 580 also functionally includes a light amount adjustment unit 582. The light amount adjustment unit 582 can adjust the amount of light emitted by the light emitting unit LD so that the photocurrent corresponding to the amount of light received by the light sensor 590 becomes a target value corresponding to a predetermined target amount of light received. In other words, the light amount adjustment unit 582 adjusts the amount of light emitted by the light emitting unit LD so that the amount of light received by the light sensor 590 becomes the target amount of light received. Specifically, the light amount adjustment unit 582 can adjust the amount of light emitted so that the amount of light received by the light sensor 560 when the light emitting unit LD is turned on at 100% light output, which will be described later, becomes the corresponding target amount of light received. The light amount adjustment unit 582 can reduce the light output of the light emitting unit LD from 100% based on the control by the LD power signal from the ASIC 575. The LD power signal is, for example, a signal output by the ASIC 575 using PWM modulation.

[0048] <Optical sensor 560> The detection signal of the optical sensor 560 is input to the ASIC 575 and is used to determine the timing of sending an image signal in the ASIC 575. By determining the image writing position based on the timing at which light reaches the optical sensor 560, it is possible to eliminate positional deviation when generating an image on the photoconductor 610. In addition, the output of the optical sensor 560 is used to check whether each light-emitting unit LD is normally lit and to evaluate the deterioration state of the exposure unit 500 according to this embodiment, which will be described later.

[0049] <Motor driver 574> The motor driver 574 outputs a motor control signal to the polygon motor 532 under the control of the ASIC 575 , and controls the rotation of the polygon mirror 530 .

[0050] <Other components on the board> In addition to the above, the board 572 is provided with a ROM 576, a RAM 577, a USB jack 578, and a LAN module 579. A low-voltage power supply 573 for generating various signals is also connected to the board 572. By attaching a USB cable to the USB jack 578, information can be transmitted and received between the control unit 570 and an external terminal connected to the USB cable. Furthermore, by using the LAN module 579, information can be transmitted and received between the control unit 570 and an external terminal connected via appropriate wireless communication.

[0051] <Detailed configuration of the optical sensor 560> The optical sensor 560 includes a photodiode 561 and an IC chip 562 . The IC chip 562 has an input terminal 563 , a current amplifier 564 , a comparator 565 , and an Ro terminal 566 .

[0052] When the beam of the laser light L is incident on the photodiode 561, a photocurrent is generated. This photocurrent is input to the input terminal 563 of the IC chip 562, amplified by the current amplifier 564, and then flows to the external gain resistor 567. At this time, the voltage VRo of the Ro terminal 566 is compared with the internal reference voltage Vref of the comparator 565. The output Vo from the comparator 565 is set to be High, for example, when Vro > Vref, and Low when Vro < Vref. As a result, the optical sensor 560 is configured to output a detection signal when the amount of incident light exceeds a predetermined threshold value, which is Vref in this example.

[0053] <Principal part of the embodiment> The polygon mirror 530 gets dirty or the like during use, causing irregular reflection of light or a decrease in reflectivity. The principal part of this embodiment is to evaluate the exposure unit 500 based on the presence or absence of the output from the optical sensor 560. Hereinafter, as an example of a method for executing the evaluation method of the exposure unit 500 of this embodiment, the control procedure executed by the control unit 570 will be described with reference to the flowchart shown in FIG. 5.

[0054] First, in S10, a predetermined warm-up of the entire exposure unit 500 is performed. Then, in S20, it is determined whether the printing conditions for printing a predetermined pattern image (details will be described later) determined in advance to evaluate the deterioration state of the exposure unit 500 are satisfied. If the printing conditions for the pattern image are satisfied, a Yes determination is made, and the process proceeds to S30, which is an example of the fifth step and will be described later.

[0055] If the test printing conditions are not met in S20, a No judgment is made, and the process proceeds to S40, which is an example of an eighth step. In S40, it is judged whether or not a predetermined evaluation execution condition for the deterioration state of the exposure unit 500 is met. A specific example of the evaluation execution condition being met is when an evaluation execution request is made via wireless communication from an external terminal connected via the LAN module 579. Alternatively, the evaluation execution condition for the deterioration state may be met when the total number of printed sheets since the previous evaluation exceeds a predetermined number. If the evaluation execution condition for the deterioration state is not met, a No judgment is made, and the process returns to S10. The conditions for determining Yes in S20 at this time may include that a print job is not being executed. To this end, an execution preparation flag may be set when Yes is determined in S20, and if this flag is set, S40 and subsequent steps may be executed at a timing that will not prevent the execution of a job, such as when printing is completed or when the device is started.

[0056] On the other hand, if the condition for evaluating the degradation state is met in S40, a Yes determination is made, and the process proceeds to S100. The detailed procedure of evaluating the degradation state S100 executed by control unit 570 will be described with reference to the flowchart shown in FIG.

[0057] First, in S102, a flag F related to signal detection by an optical sensor 560, which will be described later, is initialized to 0. After that, the process proceeds to S104, which is an example of a first step.

[0058] In S104, the polygon motor 532 is driven via the motor driver 574, and then in S106, the process waits until the rotation speed of the polygon motor 532 stabilizes. Note that the process executed by the control unit 570 in S104 corresponds to an example of a first process.

[0059] Thereafter, in S108, it is determined whether the rotation speed of polygon motor 532 has stabilized. If the rotation speed of polygon motor 532 has not stabilized, the determination is No, and the process proceeds to S100. In S110, a predetermined error notification of polygon motor 532 is performed. Specifically, for example, an appropriate error display is performed on a display unit (not shown) provided in image forming apparatus 10, or the like.

[0060] Then, the driving of the polygon motor 532 is stopped via the motor driver 574, this routine is terminated, and the process proceeds to S50 shown in FIG. 5, which will be described later.

[0061] On the other hand, if the rotation speed of the polygon motor 532 is stabilized in S108, the determination is Yes, and the process proceeds to S114. In S114, the light emitting unit LD of the semiconductor laser 510 is controlled to turn on via the LD driver 580, and the light emitting unit LD outputs laser light with 100% optical output, which is an example of a reference value. 100% optical output is an output used in normal printing. After that, in S116, waiting is performed until the optical output from the light emitting unit LD stabilizes. Then, in S118, a check is performed to see if a detection signal is input from the optical sensor 560. In other words, the detection signal is obtained from the optical sensor 560. S114, S116, and S118 are an example of a second step, and the processing performed by the control unit 570 in S114, S116, and S118 corresponds to an example of a second processing.

[0062] Thereafter, in S120, it is determined whether or not a detection signal is input from the optical sensor 560. If a detection signal is not input from the optical sensor 560, the determination is No, and the process proceeds to S122. In S122, a predetermined error notification of the specific light-emitting unit LD is performed. Specifically, for example, an appropriate error display is performed on a display unit (not shown) provided in the image forming apparatus 10, etc.

[0063] Then, in S124, the light emitting unit LD of the semiconductor laser 510 is controlled via the LD driver 580 to stop the light output from the light emitting unit LD and to turn it off. After that, in S126, the driving of the polygon motor 532 is stopped via the motor driver 574, this routine is ended, and the process proceeds to S50 shown in FIG. 5 described later.

[0064] On the other hand, if a detection signal is input from the optical sensor 560 in S120, a Yes determination is made, and the process proceeds to S128. In S128, a variable output_per representing the optical output of the light-emitting unit LD is set, and the light-emitting unit LD is controlled via the LD driver 580 so that the optical output becomes output_per=A. Note that A may be a value desired by the user, or may be a value that is fixedly determined in advance.

[0065] Then, in S130, waiting is performed until the light output from the light-emitting unit LD becomes stable, and then in S132, it is checked whether a detection signal from the optical sensor 560 is input, in other words, a detection signal from the optical sensor 560 is acquired. Then, in S134, it is determined whether a detection signal from the optical sensor 560 is input. If a detection signal from the optical sensor 560 is input, it is determined as Yes, and the process proceeds to S136. In S136, the value of the variable output_per representing the light output of the light-emitting unit LD is reduced by α, which is an example of a predetermined deviation, by changing the LD power signal. Note that the value of this α may be variable, for example, α1 in the first S136, α2 different from α1 in the second S136, and α3 which is further different in the third S136. Then, in S138, the above-mentioned flag F is set to 1, and the process returns to S130.

[0066] On the other hand, if no detection signal is input from the optical sensor 560 in S134, the result is No and the process proceeds to S140, where it is determined whether the flag F is 1 or not. If F remains 0, the result is No and the process proceeds to S142, where the value of the variable output_per representing the optical output of the light-emitting unit LD is increased by β by changing the LD power signal. Note that this value of β may be the same as the above-mentioned α, or may be a different value. Also, the value of β may be variable, for example, β1 in the first S142, β2 different from β1 in the second S142, and β3 which is further different in the third S142. Then, the process returns to S130.

[0067] S130, S132, S134, S136, S140, and S142 are an example of a third step, and the processes executed by control unit 570 in S130, S132, S134, S136, S140, and S142 correspond to an example of a third process. That is, if the value A of the initial optical output output_per from the light-emitting unit LD in S128 is relatively large, a signal check is performed in S132, and then S134 is judged as Yes, and α is subtracted from output_per in S136. After F=1 is set in S138, the process returns to S130, and the flow of S132 to S134 to S136 to S138 to S130 is repeated, and α is sequentially subtracted in S136, so that the optical output is reduced stepwise in this example. Then, when the detection signal from the optical sensor 560 is no longer input and S134 is judged as No, S140 is judged as Yes, and the process proceeds to S144. At this time, the optical output from the light-emitting unit LD when the detection signal from the optical sensor 560 is no longer obtained and S134 is judged as No corresponds to an example of the second optical output value. In addition, the light output from the light-emitting element LD when a detection signal is obtained from the optical sensor 560 and a Yes judgment is made in S134, which is one step before in the above repetition, i.e., a value that is larger than the second light output value by a predetermined deviation α, corresponds to an example of the first light output value.

[0068] On the other hand, if the value A of the initial optical output output_per from the light-emitting unit LD in S128 is relatively small, a signal check is performed in S132, a No decision is made in S134, F remains 0 and a No decision is made in S140, and β is added to output_per in S142. Thereafter, the process returns to S130, and when the flow of S132 to S134 to S140 to S142 to S130 is repeated, β is added sequentially in S142, and the optical output increases stepwise in this example, and a Yes decision is made in S134 and α is subtracted from output_per in S136. After F=1 is set in S138, the process returns to S130 and the flow of S132-S134-S136-S138-S130... is repeated, whereby the optical output is sequentially reduced by α in S136, so that in this example the optical output decreases stepwise, the detection signal from the optical sensor 560 is no longer input, S134 is judged as No, S140 is judged as Yes, and the process proceeds to S144. In this case, as in the above, the optical output from the light-emitting unit LD when the detection signal from the optical sensor 560 is no longer obtained and S134 is judged as No corresponds to an example of the second optical output value, and the optical output from the light-emitting unit LD when the detection signal from the optical sensor 560 is obtained and the judgment is Yes in the previous S134 corresponds to an example of the first optical output value.

[0069] The value A of the initial optical output output_per from the light-emitting unit LD in S128 may be set to 100% optical output, which is an example of the reference value. In this case, after checking by obtaining a detection signal from the optical sensor 560 in S132, S134 is judged as Yes, and α, which is an example of the predetermined deviation, is subtracted from output_per in S136. After F=1 is set in S138, the process returns to S130 and the flow of S132 to S134 to S136 to S138 to S130 is repeated, and α is sequentially subtracted in S136, so that the optical output is reduced stepwise in this example. That is, in this example, the optical output of the semiconductor laser 510 is reduced stepwise by the predetermined deviation from the reference value. Then, when the detection signal from the optical sensor 560 is no longer input and S134 is judged as No, S140 is judged as Yes, and the process proceeds to S144. At this time, the optical output from the light-emitting unit LD when the detection signal from the optical sensor 560 is no longer obtained and S134 is judged as No corresponds to an example of the second optical output value. Also, the optical output value from the light-emitting unit LD when the detection signal from the optical sensor 560 is obtained and S134, one step before in the above repetition, is judged as Yes corresponds to an example of the first optical output value.

[0070] As a result, in S130, S132, S134, S136, S140, and S142, the optical output of the semiconductor laser 510 is changed stepwise, and it is determined whether or not a detection signal is obtained from the optical sensor 560.

[0071] Then, in S144, which is an example of the fourth step, the value output_per+α, which is the value one step before the optical output output_per from the light emitting unit LD at this time, that is, the first optical output value, is acquired as an evaluation value of the deterioration state of the exposure unit 500. As an example, the first optical output value may be a ratio when the reference value is set to 100%. In S144, the optical output of the semiconductor laser 510 when the detection signal from the optical sensor 560 is no longer input and S134 is judged as No, that is, the second optical output value, may be acquired as an evaluation value, or both the first optical output value and the second optical output value may be acquired as evaluation values. In addition, the process executed by the control unit 570 in S144 is an example of a fourth process.

[0072] Thereafter, in S146, the light emitting unit LD of the semiconductor laser 510 is controlled via the LD driver 580 to stop the light output from the light emitting unit LD and to turn it off. Then, in S148, the driving of the polygon motor 532 is stopped via the motor driver 574, this routine is ended, and the process proceeds to S50 shown in FIG. 5 described later.

[0073] After the above S100 is completed, the process returns to FIG. 5. In S50, which is an example of a sixth step, the evaluation result of the deterioration state of the exposure unit 500, i.e., the deterioration state evaluation value which is the first optical output value determined in S144, is stored. The storage destination is, for example, a storage device built into the image forming apparatus 10, for example, a non-volatile memory (not shown) provided on the board 572. Thereafter, in S60, which is an example of a seventh step, the evaluation result of the deterioration state of the exposure unit 500, i.e., the deterioration state evaluation value which is the first optical output value determined in S144, is transmitted to an external terminal connected via the LAN module 579 and stored in the external terminal. After the completion of S60, the process returns to S10.

[0074] Meanwhile, in S30 as an example of a fifth step to which the process proceeds when a Yes determination is made in S20, a predetermined pattern image is printed in order to evaluate the deterioration state of the exposure unit 500. Specifically, as in the normal printing process, a toner image based on an electrostatic latent image of the photoconductor 610 formed by irradiating the laser light L from the exposure unit 500 is transferred to the transfer medium W, and the pattern image 800 is printed.

[0075] For example, in the example shown in Fig. 7, a plurality of pattern images 800 are arranged in the sub-scanning direction while being shifted in the main scanning direction. The pattern image 800 is composed of a left pattern portion 800L having a U-shape facing left and a right pattern portion 800R having a U-shape facing right. The left pattern portion 800L includes two first fill patterns 800a each extending in the main scanning direction and a connecting pattern portion 800c extending to connect between the two first fill patterns 800a, and the right pattern portion 800R includes a second fill pattern 800b arranged with a gap m in the main scanning direction from the first fill pattern 800a, and a connecting pattern portion 800d extending to connect between the two second fill patterns 800ab.

[0076] The backgrounds of the multiple pattern images 800 are filled with halftone CL of the color of the pattern image. Halftone is, for example, an image of a binary dot pattern in which the filling area per predetermined area is a predetermined value.

[0077] 8(a) and 8(b) show an example of the print result of the pattern image 800 when the exposure section 500 deteriorates as described above. In the example of FIG. 8(a), bleeding due to a decrease in reflectance or diffuse reflection of the polygon mirror 530 is seen in the pattern images 800 from the first to sixth rows from the top in the figure, and in particular, bleeding occurs in the gap m between the first filling pattern 800a and the second filling pattern 800b. In the example of FIG. 8(b), bleeding due to a decrease in reflectance or diffuse reflection of the polygon mirror 530 is seen in the pattern images 800 from the first to fifth rows from the bottom in the figure, as described above, and bleeding also occurs in the gap m. The exposure section 500 can be evaluated based on the bleeding in the gap m, in other words, the print density of the gap m. Specifically, the evaluation may be performed visually by an operator, based on the reading result of a reading device provided in the image forming apparatus 10, or based on the reading result of a reading device of an external device such as a camera of a mobile terminal.

[0078] FIG. 8(c) shows an example of a pattern image 850 in another embodiment. In this example, a plurality of pattern images 850 are arranged in the sub-scanning direction while being shifted in the main scanning direction. The pattern image 850 is composed of a left pattern portion 850L and a right pattern portion 850R. The left pattern portion 800L has one first filling pattern 850a extending in the main scanning direction, and the right pattern portion 800R has a second filling pattern 850b arranged with a gap m in the main scanning direction from the first filling pattern 850a. As described above, the background of the plurality of pattern images 850 is filled with a halftone CL of the color of the pattern image.

[0079] Fig. 8(d) shows an example of the print result of the pattern image 850 when deterioration of the exposure unit 500 occurs. In the example of Fig. 8(d), bleeding due to a decrease in the reflectance of the polygon mirror 530 or diffuse reflection is seen in the pattern images 850 from the first to fifth rows from the top in the figure, and in particular bleeding occurs in the gap m between the first filling pattern 850a and the second filling pattern 850b.

[0080] <Effects of the embodiment and modified examples> As described above, in the exposure unit 500 of the image forming apparatus 10 of this embodiment, the optical sensor 560 is configured to output a detection signal when the amount of incident light exceeds the internal reference voltage Vref of the comparator 565. In the evaluation method of the exposure unit 500 of this embodiment, S104, S114 to S118, and S130 to S144 are executed. In S104, the polygon mirror 530 is rotated, and in S114, S116, and S118, the light of the semiconductor laser 510 is output and a detection signal from the optical sensor 560 is obtained. In S130, S132, S134, S136, S140, and S142, the optical output of the semiconductor laser 510 is changed to determine whether or not a detection signal is obtained from the optical sensor 560. In S144, when a detection signal is obtained from the optical sensor 560 at a first optical output value of the semiconductor laser 510 and a detection signal is no longer obtained from the optical sensor 560 at a second optical output value that is smaller than the first optical output value by α, at least one of the first optical output value or the second optical output value is obtained. When the output value is decreased by α from the first optical output value and the detection signal is no longer obtained at the second optical output value, the first optical output value is the lower limit output at which the detection signal is obtained from the optical sensor 560. That is, since the larger the first optical output value, the lower the reflectance of the polygon mirror 530, the deterioration state of the exposure unit 500 can be evaluated based on the magnitude of this first optical output value. This is because the larger the first optical output value, the more advanced the deterioration. Note that the evaluation can also be performed using the first optical output value and / or the second optical output value. As a result, the deterioration state of the exposure unit 500, which is mainly caused by dirt on the polygon mirror 530, can be evaluated without disassembling the device. In particular, the decrease in reflectance due to dirt on the part of the polygon mirror 530 that reflects toward the optical sensor 560, which is the part of the polygon mirror 530 that is most susceptible to dirt, can be evaluated. As described above, the evaluation method of the exposure section 500 of this embodiment does not require an A / D converter or the like in the sensor output detection circuit, which is a configuration that is not necessary for the image forming apparatus 10, thereby preventing the device configuration from becoming complicated and costs from increasing.

[0081] In particular, in this embodiment, in S114, S116, and S118, the optical output of the semiconductor laser 510 is set to a predetermined 100% optical output, and a detection signal is obtained from the optical sensor 560. In S130, S132, S134, S136, S140, and S142, the optical output of the semiconductor laser 510 is reduced stepwise by α from the above 100% optical output, and it is determined whether or not a detection signal is obtained from the optical sensor 560. In S144, a first optical output value that is one step before the second optical output value of the semiconductor laser 510 when the detection signal from the optical sensor 560 is no longer obtained is obtained. After the optical output of the semiconductor laser 510 is set to 100% optical output and a detection signal of the optical sensor 560 is obtained, the optical output is gradually lowered until a detection signal is no longer obtained at the second optical output value, at which point the deterioration state of the exposure section 500 can be evaluated using the first optical output value at the immediately preceding stage. By simply gradually lowering the optical output from 100% optical output in stages, the deterioration state can be evaluated smoothly and quickly.

[0082] In this embodiment, in particular, in S30, predetermined pattern images 800, 850 are formed and printed on the transfer medium W. The pattern images 800, 850 include first filling patterns 800a, 850a extending in the main scanning direction, and second filling patterns 800b, 850b arranged with a gap m in the main scanning direction from the first filling patterns 800a, 850a. As a result, when the polygon mirror 530 is dirty, as shown in an example in FIG. 8(a), FIG. 8(b), and FIG. 8(d), the deterioration state of the exposure unit 500 caused by the dirt on the polygon mirror 530 can be evaluated based on the fact that the printing of the gap m becomes darker. In particular, the diffuse reflection of light caused by the dirt on the part of the polygon mirror 530 that is actually used for printing can be evaluated.

[0083] 7 and 8(c), in this embodiment, a plurality of predetermined pattern images 800, 850 are arranged in the sub-scanning direction while being shifted in the main scanning direction, thereby making it possible to evaluate dirt in a plurality of ranges in the reflection area of ​​the polygon mirror 530.

[0084] Furthermore, particularly in this embodiment, the background of the predetermined pattern images 800, 850 is filled with a halftone CL of the color of the predetermined pattern images 800, 850. As a result, when the gap m is exposed to light due to diffuse reflection caused by dirt on the polygon mirror 530, it is easy to compare the print density of the background filled with the halftone CL and the print density of the gap m as shown in Figures 8(a), 8(b), and 8(d), making it easy to detect dirt.

[0085] Furthermore, because the degree of contamination of the polygon mirror 530 differs depending on the installation environment of the device, such as whether the air is dirty, the degree of deterioration of the exposure unit 500 also differs depending on the environment. In particular, in this embodiment, the total number of printed sheets since the previous evaluation exceeds a predetermined number, and this is set as the condition for executing evaluation of the deterioration state in S40, so that S104, S114 to S118, and S130 to S144 can be executed every time the predetermined number of printed sheets is counted. As a result, the degree of deterioration of the exposure unit 500 can be accurately evaluated.

[0086] In this embodiment, at least one of the first light output value and the second light output value acquired at S144 is stored in a non-volatile memory device built into the device at S50, so that the degree of deterioration can be evaluated from the history of the stored contents.

[0087] In particular, in this embodiment, in S60, at least one of the first light output value and the second light output value acquired in S144 is stored in an external terminal such as a PC, a smartphone, or a server connected to the apparatus. As a result, the external terminal can evaluate the exposure unit 500.

[0088] In particular, in this embodiment, the existence of a request to execute evaluation from an external terminal is regarded as the establishment of the condition for executing evaluation of the deterioration state in S40, so that S104, S114 to S118, and S130 to S144 can be executed. As a result, the deterioration state can be obtained whenever desired by a management system or the like.

[0089] In the above embodiment, the evaluation value is the first optical output value or the second optical output value. For example, when the scanning unit 505 is new and the first optical output value obtained by the deterioration state evaluation is A, and the first optical output value obtained by the current deterioration state evaluation is B, Evaluation score = (BA) / (reference score - A) x 100(%) It may be done like this.

[0090] In addition to the above, the methods according to the above embodiments and their modifications may be used in appropriate combination.

[0091] Although not specifically illustrated, the present invention can be implemented with various modifications without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0092] 500 Exposure section (an example of a scanning exposure device) 505 Scanning Unit 510 Semiconductor Laser 530 Polygon Mirror 560 Light Sensor 570 Control Unit 600 Electrophotographic Process Section 610 Photoreceptor 700 Fixing unit L Laser light LD light emitting section W Transfer medium

Claims

1. a scanning exposure device including a light source having a semiconductor laser, a polygon mirror that deflects light from the semiconductor laser, and an optical sensor that detects the light deflected by the polygon mirror and is configured to output a detection signal when an amount of incident light exceeds a predetermined threshold; an electrophotographic process unit having a photoconductor exposed by the scanning exposure device and forming a toner image on a transfer medium; a fixing device for fixing the toner image onto the transfer medium; A method for evaluating the scanning exposure device in an image forming apparatus comprising: a first step of rotating the polygon mirror; a second step of outputting light from the semiconductor laser and acquiring a detection signal from the optical sensor; a third step of changing the optical output of the semiconductor laser and determining whether or not a detection signal is obtained from the optical sensor; a fourth step of acquiring at least one of the first optical output value and the second optical output value when the detection signal is obtained from the optical sensor at a first optical output value of the semiconductor laser and the detection signal is no longer obtained from the optical sensor at a second optical output value of the semiconductor laser that is smaller than the first optical output value by a predetermined deviation; 1. A method for evaluating a scanning exposure apparatus, comprising:

2. In the second step, acquiring a detection signal from the optical sensor using the optical output of the semiconductor laser as a reference value; In the third step, The optical output of the semiconductor laser is gradually decreased by the predetermined deviation from the reference value, and it is determined whether or not a detection signal is obtained from the optical sensor; In the fourth step, The first optical output value, which is one step before the second optical output value at which the detection signal from the optical sensor is no longer obtained by the stepwise reduction, is obtained.

2. The method for evaluating a scanning exposure apparatus according to claim 1.

3. moreover, a fifth step of forming and printing a predetermined pattern image on the transfer medium, the pattern image having a first fill pattern extending in a main scanning direction and a second fill pattern disposed with a gap in the main scanning direction from the first fill pattern, and evaluating the scanning exposure device based on the print density of the gap. have 2. The method for evaluating a scanning exposure apparatus according to claim 1.

4. The predetermined pattern images are arranged in a plurality in the sub-scanning direction while being shifted in the main scanning direction.

4. The method for evaluating a scanning exposure apparatus according to claim 3.

5. The background of the predetermined pattern image is filled with a halftone of the color of the predetermined pattern image.

4. The method for evaluating a scanning exposure apparatus according to claim 3.

6. The image forming apparatus is configured to execute the first step, the second step, the third step, and the fourth step to perform evaluation of the scanning exposure device every time the number of printed sheets exceeds a predetermined number.

2. The method for evaluating a scanning exposure apparatus according to claim 1.

7. the image forming apparatus has a storage device built in the image forming apparatus, moreover, a sixth step of storing at least one of the first light output value and the second light output value obtained in the fourth step in the storage device.

2. The method for evaluating a scanning exposure apparatus according to claim 1.

8. moreover, a seventh step of storing at least one of the first light output value and the second light output value acquired in the fourth step in an external terminal connected to the image forming apparatus; 2. The method for evaluating a scanning exposure apparatus according to claim 1.

9. moreover, an eighth step of determining whether or not an evaluation execution request has been received from the external terminal; having When an evaluation execution request is received from the external terminal, the first step, the second step, the third step, and the fourth step are executed.

9. The method for evaluating a scanning exposure apparatus according to claim 8.

10. a light source having a semiconductor laser; a polygon mirror that deflects light from the semiconductor laser; an optical sensor that detects light deflected by the polygon mirror, the optical sensor being configured to output a detection signal when an amount of incident light exceeds a predetermined threshold; A control unit; A scanning exposure apparatus having The control unit is a first process of rotating the polygon mirror; a second process of outputting light from the semiconductor laser and acquiring a detection signal from the optical sensor; a third process of changing an optical output of the semiconductor laser and determining whether or not a detection signal is obtained from the optical sensor; a fourth process of acquiring at least one of the first optical output value and the second optical output value when the detection signal from the optical sensor is obtained at a first optical output value of the semiconductor laser and the detection signal from the optical sensor is no longer obtained at a second optical output value of the semiconductor laser that is smaller than the first optical output value by a predetermined deviation; A scanning exposure apparatus comprising:

Images