JP2017102149A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can perform suitable cleaning of a light transmissive member of an exposure part according to the consumption and use environment of toner.SOLUTION: An image forming apparatus comprises photoreceptor drums, an exposure part, a cleaning part, a humidity detection part, a dot count part and a control part. After completion of a print job, the control part causes the cleaning part to perform cleaning of a surface of a light transmissive member of the exposure part when the amount of dirt on the light transmissive member exceeds a predetermined threshold, the amount of dirt derived by calculating by using the number of dots in a print image consumed by toner in one print job output from the dot count part and a humidity factor derived on the basis of humidity information output from the humidity detection part.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an image forming apparatus represented by a copying machine.

  An image forming apparatus such as a copying machine, a printer, or a facsimile machine exposes the surface of a photosensitive drum, which is an image carrier, while scanning with a light beam such as a laser beam to form an electrostatic latent image on the surface of the photosensitive drum. An optical scanning unit may be provided as the exposure unit. The optical scanning unit is provided with an opening through which laser light emitted from a light source passes when traveling toward the surface to be scanned, and a light transmissive member that covers the opening. In particular, when the optical scanning unit is disposed below the photosensitive drum, it is indispensable to provide a light transmissive member in the opening.

  Dust such as toner scattered from the image forming unit is prevented from entering the inside of the optical scanning unit by the light transmitting member in the opening, but adheres to the surface of the light transmitting member. This hinders the progress of the laser beam and may cause a problem that an accurate electrostatic latent image cannot be formed on the surface of the photosensitive drum. Therefore, in order to solve such problems, an image forming apparatus including a cleaning unit for cleaning and removing dust such as toner has been proposed, and examples thereof are disclosed in Patent Documents 1 and 2.

  A conventional image forming apparatus described in Patent Document 1 includes a cleaning unit that collects toner remaining on the surface of a photosensitive drum, and a data amount that counts a data amount for writing an electrostatic latent image on the photosensitive drum. A counting unit. The image forming apparatus controls the cleaning unit to execute toner discharge processing when the data amount exceeds a threshold value. This prevents a reduction in cleaning capability due to clogging of the toner collected in the cleaning unit.

  The conventional image forming apparatus described in Patent Document 2 has an intermediate transfer member cleaning device that removes toner on the surface of the intermediate transfer belt, and a condition when toner is removed by the intermediate transfer member cleaning device based on image information. Control means for controlling. This image forming apparatus increases the number of times the toner image area on the intermediate transfer belt passes through the intermediate transfer body cleaning device as the toner image ratio is higher. Accordingly, even when the state of the toner remaining on the surface of the intermediate transfer belt differs according to the image information, the toner is favorably removed.

JP 2001-034134 A JP 2006-113217 A

  However, the conventional image forming apparatuses described in Patent Documents 1 and 2 have a toner amount remaining on the surface of the photosensitive drum and the surface of the intermediate transfer belt based only on the data amount and image information relating to the image printed on the paper. The influence of the surrounding environment of the image forming apparatus is not taken into consideration. Therefore, the amount of toner to be removed varies depending on the surrounding environment of the image forming apparatus, and there is a problem that cleaning suitable for each image forming apparatus cannot be executed. That is, since the actual amount of dirt due to the toner of the image forming apparatus is not taken into consideration, there is a concern that cleaning may be insufficient or excessive.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above points. An image forming apparatus capable of executing suitable cleaning corresponding to the amount of toner consumed and the use environment with respect to cleaning of the light transmissive member of the exposure unit. The purpose is to provide.

  In order to solve the above problems, the image forming apparatus of the present invention includes a photosensitive drum, an exposure unit, a cleaning unit, a humidity detection unit, a dot count unit, and a control unit. The photosensitive drum is used as an image carrier for forming a toner image. The exposure unit has a light transmissive member at the light emitting portion with respect to the photosensitive drum, and performs exposure by irradiating the surface of the photosensitive drum with light. The cleaning unit cleans and removes deposits on the surface of the light transmissive member in the exposure unit. The humidity detector detects the humidity of the surrounding environment. The dot count unit measures the number of toner consumption dots in an image printed on paper. The control unit controls operations of the photosensitive drum, the exposure unit, and the cleaning unit. Further, after the print job is completed, the control unit uses the toner consumption dot number of the print image in one print job output from the dot count unit and the humidity coefficient derived based on the humidity information output from the humidity detection unit. When the contamination amount of the light transmissive member derived by the calculation exceeds a predetermined threshold value, the cleaning unit performs cleaning of the surface of the light transmissive member.

  According to the configuration of the present invention, the stain amount of the light transmissive member of the exposure unit corresponding to the number of dots of the image printed on the paper and the humidity of the surrounding environment of the image forming apparatus is derived. Then, the cleaning unit is caused to clean the surface of the light transmissive member at a predetermined timing based on the amount of dirt. Therefore, in the image forming apparatus, it is possible to execute suitable cleaning of the light transmissive member corresponding to the toner consumption amount and the usage environment.

1 is a front view of an image forming apparatus according to a first embodiment of the present invention. 1 is a block diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a vertical sectional front view of an exposure unit of the image forming apparatus according to the first embodiment of the present invention. 1 is an external perspective view of an exposure unit of an image forming apparatus according to a first embodiment of the present invention. 3 is a flowchart illustrating an example of a cleaning process performed by a cleaning unit of an exposure unit of the image forming apparatus according to the first embodiment of the present invention. 10 is a flowchart illustrating an example of a cleaning process performed by a cleaning unit of an exposure unit of an image forming apparatus according to a second embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following contents.

<First Embodiment>
First, an image forming operation and a printing operation of the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an example of a front view of the image forming apparatus, and FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus. This image forming apparatus is a so-called multi-function machine having functions such as copying, image reading (scanning), printer, facsimile, and the like, and is of a color printing type in which a toner image is transferred onto a sheet using an intermediate transfer belt.

  As shown in FIG. 1, the image forming apparatus 1 has a document transport unit 3 placed on the upper surface of a main body 2, and includes a document image reading unit 4 inside the main body 2 below it. When the user causes the image forming apparatus 1 to execute an image reading job including facsimile transmission, a document on which an image such as a character, a figure, or a pattern is drawn is stacked on the document transport unit 3 or the document is stored in the document image reading unit 4. Or placed on a contact glass (not shown) on the upper surface. In the document conveying section 3, one or a plurality of documents are separated and sent out one by one, and the document image reading section 4 reads the image. With respect to the original on the contact glass, the image is read by scanning light inside the original image reading unit 4. The image data of the read original image is stored in, for example, the storage unit 23 (see FIG. 2).

  A command for the user to cause the image forming apparatus 1 to execute a print job, an image reading job, and a facsimile transmission job is received using an operation panel 5 provided on the upper side of the main body 2 and on the front side of the document image reading unit 4. For example, the operation panel 5 accepts settings such as printing conditions such as the type and size of paper used for printing, enlargement / reduction, and presence / absence of duplex printing, and inputs settings such as a fax number and a sender name in facsimile transmission. Or accept. Furthermore, the operation panel 5 also serves as a notification unit for notifying the user of the operation state, cautions, error messages, and the like of the device by displaying them on the display unit 5w.

  On the other hand, the image forming apparatus 1 includes a printing unit 6 for executing a print job in a portion below the image reading unit 4 of the main body 2. The printing unit 6 includes a paper feeding unit 7, a paper transport unit 8, an exposure unit 30, an image forming unit 10, a transfer unit 12, and a fixing unit 13.

  The paper feed unit 7 stacks and stores the paper P, and separates the paper P one by one and sends it out to the paper transport unit 8. The paper transport unit 8 receives the paper P sent out from the paper feed unit 7 and transports the paper P vertically upward along the right side surface of the main body 2 to the secondary transfer unit 12 w of the transfer unit 12.

  When printing image data of a document, the image data information is subjected to image processing and the like via the control unit 20 shown in FIG. The exposure unit 30 irradiates the image forming unit 10 with laser light controlled based on the image data.

  The image forming unit 10 is provided with four units: an image forming unit 10Y for yellow, an image forming unit 10M for magenta, an image forming unit 10C for cyan, and an image forming unit 10K for black. In the following description, the identification symbols “Y”, “M”, “C”, and “B” representing each color are omitted unless particularly limited.

  The transfer unit 12 includes an intermediate transfer belt 12z, primary transfer units 12Y, 12M, 12C, and 12K, a secondary transfer unit 12w, and an intermediate transfer cleaning unit 12x. The four image forming units 10 are arranged in a so-called tandem system arranged in a line from the upstream side to the downstream side in the rotation direction of the intermediate transfer belt 12z.

  In each color image forming unit 10, an electrostatic latent image of a document image is formed by the laser light emitted from the exposure unit 30, and a toner image is developed from the electrostatic latent image. At this time, the image forming unit 10 forms an output image for each line from the image data of the original image stored in the storage unit 23, for example, in the direction intersecting the paper transport direction. Then, in the output image (toner image) formed by the image forming unit 10, that is, the image printed on the paper P, the dot count unit 24 (see FIG. 2) determines the number of toner consumption dots, which is the number of dots on the paper P. Measure sequentially.

  The toner images are primarily transferred onto the surface of the intermediate transfer belt 12z by primary transfer units 12Y, 12M, 12C, and 12K disposed above the image forming units 10Y, 10M, 10C, and 10K for the respective colors. The toner image of each image forming unit 10 is transferred to the intermediate transfer belt 12z at a predetermined timing along with the rotation of the intermediate transfer belt 12z, whereby four colors of yellow, magenta, cyan, and black are formed on the surface of the intermediate transfer belt 12z. A color toner image is formed by superimposing the color toner images.

  The color toner image on the surface of the intermediate transfer belt 12z is transferred to the paper P sent in synchronization by the paper transport unit 8 at the secondary transfer nip portion formed in the secondary transfer unit 12w. The intermediate transfer cleaning unit 12x scrapes and cleans the toner remaining on the surface of the intermediate transfer belt 12z after the secondary transfer.

  The sheet P on which the unfixed toner image has been transferred at the secondary transfer nip is sent to the fixing unit 13 and is sandwiched between the heating roller and the pressure roller, and the toner image is heated and pressed to be fixed on the sheet P. The The paper P discharged from the fixing unit 13 is output to the in-body paper discharge unit 15 through the paper discharge port 14. In this way, the printing unit 6 prints the original image on the paper P.

  The image forming apparatus 1 includes a CPU 21 and an image processing unit 22 shown in FIG. 2 and a control unit 20 composed of other electronic components (not shown) for operation control of the entire apparatus. The control unit 20 uses a central processing unit (CPU) 21 and an image processing unit 22 to control components such as the original image reading unit 4 and the printing unit 6 based on programs and data stored and input in the storage unit 23. Thus, a series of printing operations is realized. Note that the printing unit 6 includes constituent elements, such as a sheet feeding unit 7, a sheet conveying unit 8, an exposure unit 30, an image forming unit 10, a transfer unit 12, and a fixing unit 13. The elements are linked to execute printing of the original image on the paper P.

  Further, the image forming apparatus 1 includes a communication unit 25 for performing communication such as facsimile transmission / reception with an external communication device or a computer (see FIG. 2). The communication unit 25 is connected to a telephone line or a network line, and uses these lines to exchange image data with an external communication device or computer. The control unit 20 causes the communication unit 25 to execute transmission and reception of data to an external communication device or the like. The image data of the original image received from the outside is stored in the storage unit 23, for example.

  In addition, the image forming apparatus 1 includes a humidity detector 26 (see FIG. 2). The humidity detector 26 is provided in the image forming apparatus 1 in order to detect the humidity of the surrounding environment of the image forming apparatus 1. The humidity detector 26 is composed of, for example, a capacitance type or electric resistance type humidity sensor using a polymer moisture sensitive material, and detects the relative humidity of the surroundings. The controller 20 receives an output signal corresponding to the humidity information detected by the humidity detector 26.

  Next, the configuration of the exposure unit 30 will be described with reference to FIGS. 3 and 4 in addition to FIGS. 1 and 2. 3 and 4 are a vertical sectional front view and an external perspective view of the exposure unit 30, respectively.

  The exposure unit 30 is disposed below the image forming unit 10 as shown in FIG. The exposure unit 30 is to be mounted on the tandem type image forming apparatus 1 provided with the four photosensitive drums 11Y, 11M, 11C, and 11K shown in FIG. 3 corresponding to each of four colors of yellow, magenta, cyan, and black. This is a designed optical scanning unit (laser scanning unit).

  The exposure unit 30 includes a light source 31, a polygon mirror 32, and an optical system 40 inside a housing 30a configured in a box shape as shown in FIGS.

  Four independent light sources 31 are provided corresponding to the four colors, and are arranged in the vicinity of the polygon mirror 32. The light source 31 is constituted by a laser diode having a specification for irradiating a light beam in a visible region, for example, a laser beam of about 670 nm. The polygon mirror 32 has a regular polygonal shape in plan view and is provided with a plurality of reflecting surfaces for reflecting laser light around it, and is rotated around a vertical axis by a motor (not shown).

  Each of the laser beams emitted from the four light sources 31 is incident on the reflecting surface around the polygon mirror 32 while being shifted by a minute angle in the sub-scanning direction (vertical direction in FIG. 3). The polygon mirror 32 reflects each laser beam on its reflection surface while rotating and guides it to the optical system 40 while deflecting it in the main scanning direction (perpendicular to the paper surface of FIG. 3).

  The optical system 40 is provided in a region inside the housing 30a where the laser light reflected by the polygon mirror 32 travels. The optical system 40 includes a first fθ lens 41, a second fθ lens 42, and reflection mirrors 43, 44, and 45.

  The first fθ lens 41 deflects each laser beam corresponding to each color at a constant speed in the main scanning direction, and slightly widens the angle of each laser beam in the sub-scanning direction while correcting adverse effects on scanning. Each laser beam that has passed through the first fθ lens 41 is reflected by the reflection mirrors 43, 44, and 45, reaches the surface of the photosensitive drum 11 that is the surface to be scanned, and forms an image. Each laser beam that has passed through the first fθ lens 41 passes through the second fθ lens 42 before reaching the surface of the photosensitive drum 11.

  A flat lid 30b shown in FIGS. 3 and 4 is provided on the upper surface of the housing 30a. The lid 30b includes an opening 33 through which the laser light emitted from the light source 31 passes toward the surface to be scanned, and a light transmissive member 34 that covers the opening 33. The opening 33 and the light transmissive member 34 are provided at four locations corresponding to the four colors of laser light. The four openings 33 and the light transmissive member 34 are arranged side by side along the rotation direction of the intermediate transfer belt 12z, similarly to the four photosensitive drums 10 corresponding to the respective laser beams.

  The four openings 33 and the light transmissive member 34 have a rectangular shape in plan view extending in the main scanning direction. The light transmissive member 34 is made of, for example, dustproof glass, and is provided so as to close the opening 33 so that dust such as scattered toner does not enter the housing 30 a from the opening 33.

  A cleaning portion 50 of the light transmissive member 34 shown in FIG. 4 is provided in a region corresponding to the light transmissive member 34 outside the housing 30a and the lid 30b.

  As shown in FIGS. 2 and 4, the cleaning unit 50 of the light transmissive member 34 includes a slide member 51, a cleaning member 52, a wire 53, a pulley 54, a drive mechanism 55, a cleaning motor 56, a drive circuit unit 57, and a current detection unit. 58.

  The slide member 51 is a rod-like member that extends along the direction in which the four light transmissive members 34 are arranged, and is disposed close to and above the light transmissive member 34 with a predetermined interval. The slide member 51 is supported by a guide portion (not shown) extending along the main scanning direction, that is, the longitudinal direction of the light transmitting member 34, and can slide and move in the longitudinal direction of the light transmitting member 34.

  The cleaning member 52 is formed of, for example, a brush, and four corresponding to the four light transmissive members 34 are provided on the lower surface of the slide member 51. Each of the four cleaning members 52 comes into contact with the upper surface of the corresponding light transmissive member 34 (the outer surface of the exposure unit 30). The cleaning member 52 only needs to be able to clean and remove deposits on the surface of the light transmissive member 34 and does not damage the surface of the light transmissive member 34. In addition to a brush, for example, sponge, felt, non-woven fabric, etc. A resin blade may also be used.

  The wire 53 is wound around two pulleys 54 so as to form an ellipse extending along the longitudinal direction of the light transmissive member 34. The slide member 51 is fixed to one place of the wire 53.

  One of the pulleys 54 is connected to a gear of a drive mechanism 55 composed of a plurality of gear groups. The drive mechanism 55 is connected to a cleaning motor 56 that is a drive unit. As the cleaning motor 56, for example, a DC brushless motor capable of normal rotation and reverse rotation is adopted, but there is no particular limitation on the type of the motor. The drive circuit unit 57 receives a command from the control unit 20 and performs switching of power supply to the cleaning motor 56 (rotation ON / OFF).

  When the cleaning motor 56 is driven, the pulley 54 rotates via the drive mechanism 55. As the pulley 54 rotates, the wire 53 rotates in the extending direction, and the slide member 51 slides along the longitudinal direction of the light transmissive member 34. Thereby, the cleaning member 52 cleans and removes the deposits on the surface of the light transmissive member 34.

  The current detection unit 58 detects, for example, a voltage between terminals of a resistor (not shown) provided to convert a current flowing through the cleaning motor 56 into a voltage, and performs cleaning by calculation using the voltage value and the resistance value of the resistor. The amount of current flowing through the motor 56 can be detected. The current detection unit 58 transmits information on the detected current value to the control unit 20.

  Then, after the print job is completed, the control unit 20 of the image forming apparatus 1 derives the stain amount of the light transmissive member 34 based on the toner amount used for printing in the printing operation and the humidity of the surrounding environment. The control unit 20 causes the cleaning unit 50 to clean the surface of the light transmissive member 34 when the amount of dirt exceeds a predetermined threshold value. More specifically, the amount of dirt on the light transmissive member 34 is the number of dots consumed by toner for all four colors of a print image in one print job output by the dot count unit 24, and the humidity information output by the humidity detection unit 26. And a humidity coefficient derived based on the above. More specifically, the amount of dirt can be calculated by the following equation.

Stain amount = (number of toner consumption dots of a print image in one print job) × (humidity coefficient)
Humidity coefficient = 1 / (Relative humidity during print job execution [%])

  The above calculation formula for the amount of dirt indicates that as the number of toner consumption dots in the printed image increases, the amount of toner consumption increases and the light transmissive member 34 becomes more easily contaminated. As the humidity increases, the amount of dirt in the atmosphere decreases. , Has been taken into account. Note that the above calculation formula for the humidity coefficient is an example, and other formulas may be used as long as it is considered that the higher the humidity, the less contamination in the atmosphere. A threshold value for determining the amount of dirt is determined in advance and stored in the storage unit 23.

  When the contamination amount exceeds the threshold value and the cleaning of the surface of the light transmissive member 34 is executed, the contamination amount is reset. On the other hand, if the stain amount does not exceed the threshold value, the control unit 20 stores the stain amount in the storage unit 23 in order to add the stain amount to the stain amount derived after the end of the next print job.

  Next, the cleaning process of the light transmissive member 34 by the cleaning unit 50 of the exposure unit 30 will be described along the flow shown in FIG. FIG. 5 is a flowchart showing an example of the cleaning process by the cleaning unit 50 of the exposure unit 30.

  When the print job is completed, the image forming apparatus 1 starts the cleaning process of the light transmissive member 34 by the cleaning unit 50 (start of FIG. 5). This cleaning process is started every time a print job is completed.

  In step # 101, the control unit 20 derives the amount of dirt on the light transmissive member. At this time, the control unit 20 obtains the toner consumption dot numbers of all four colors in the print image in one print job output from the dot count unit 24 and the humidity information output from the humidity detection unit 26, and The amount of dirt is derived based on the calculation formula.

  If the stain amount derived after the end of the previous print job is stored in the storage unit 23, the stored previous stain amount is added to the stain amount derived this time. On the other hand, when the surface of the light transmissive member 34 is cleaned after the end of the previous print job, 0 (zero) should be set in advance as the initial value of the stain amount.

  In step # 102, the control unit 20 determines whether or not the derived amount of dirt exceeds a predetermined threshold value. If the amount of dirt exceeds the threshold, the process proceeds to step # 103. When the amount of dirt does not exceed the threshold value, the cleaning process of the light transmissive member 34 is ended (end of FIG. 5).

  In step # 103, the control unit 20 causes the cleaning unit 50 of the exposure unit 30 to start cleaning the surface of the light transmissive member 34. At this time, the control unit 20 transmits an operation command to the drive circuit unit 57, causes the cleaning motor 56 to start rotating, causes the slide member 51 to slide along the longitudinal direction of the light transmissive member 34, and cleans the cleaning member 52. Thus, cleaning and removal of deposits on the surface of the light transmissive member 34 are executed. Then, since the surface of the light transmissive member 34 has been cleaned, the amount of dirt is reset to 0 (zero).

  In step # 104, the control unit 20 causes the current detection unit 58 of the cleaning unit 50 to detect the amount of current flowing through the cleaning motor 56 when the surface of the light transmissive member 34 is cleaned. At this time, the control unit 20 receives information on the current value detected by the current detection unit 58 from the current detection unit 58.

  In Step # 105, the control unit 20 determines whether or not the current value of the cleaning motor 56 at the time of cleaning the surface of the light transmissive member 34 exceeds a predetermined threshold value. A threshold value for determining the current value is determined in advance and stored in the storage unit 23. If the current value exceeds the threshold value, the process proceeds to step # 106. If the current value does not exceed the threshold value, the cleaning process for the light transmissive member 34 is terminated (END in FIG. 5).

  In step # 106, the control unit 20 determines whether or not the cleaning of the surface of the light transmissive member 34 performed repeatedly and repeatedly has reached a predetermined number of times (for example, three times in this case). To do. If cleaning has already been performed three times in succession, the process proceeds to step # 107. If the cleaning has not been performed three times in succession, the process returns to step # 103 and the cleaning of the surface of the light transmissive member 34 is started.

  In step # 107, the control unit 20 causes the display unit 5w, which is a notification unit, to display precautions, an error message, and the like to notify the user of error information. At this time, the control unit 20 causes the display unit 5w to display, for example, a message that prompts the user to clean the surface of the light transmissive member 34 with his / her hand.

  In step # 108, when the amount of dirt does not exceed the threshold value in step 102, the control unit 20 stores the amount of dirt in the storage unit 23. The stored amount of stain is added to the amount of stain derived after the end of the next print job.

  Then, the cleaning process of the light transmissive member 34 is completed (end of FIG. 5).

Second Embodiment
Next, an image forming apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a flowchart illustrating an example of the cleaning process performed by the cleaning unit of the exposure unit of the image forming apparatus. Since the basic configuration of this embodiment is the same as that of the first embodiment described above, the description of the configuration common to the first embodiment may be omitted.

  The image forming apparatus 1 according to the second embodiment performs the surface cleaning process of the light transmissive member 34 according to the operation flow illustrated in FIG. 6.

  When the cleaning process of the light transmissive member 34 by the cleaning unit 50 is started (start of FIG. 6), the control unit 20 derives the amount of dirt on the light transmissive member 34 in step # 201.

  Here, when the dot count unit 24 measures the toner consumption dots of the output image (toner image) formed by the image forming unit 10, the number of all-color dots based on the toner of all four colors and each color dot based on the toner of each color Measure numbers and numbers individually. The control unit 20 calculates the total color smear amount derived by calculation using the number of all color dots of the print image and the humidity coefficient in one print job, and the number of each color dot of the print image in one print job. Each color stain amount derived by calculating using the humidity coefficient is obtained.

  In step # 202, the control unit 20 determines whether or not the derived all-color stain amount exceeds a predetermined all-color threshold value. Note that the all-color threshold value for determining the all-color stain amount is determined in advance and stored in the storage unit 23. When the amount of all color stains exceeds the all color threshold, the process proceeds to step # 203. If the all-color stain amount does not exceed the all-color threshold, the process proceeds to step # 204.

  In Step # 203, the control unit 20 determines whether or not each derived color stain amount has exceeded a predetermined color threshold value. Each color threshold value for determining each color stain amount is determined in advance and stored in the storage unit 23. If each color stain amount exceeds each color threshold, the process proceeds to step # 205. When the amount of each color stain does not exceed each color threshold, the process proceeds to step # 206.

  In step # 204, the control unit 20 determines whether or not each derived color stain amount exceeds a predetermined color threshold value. If each color stain amount exceeds each color threshold, the process proceeds to step # 206. When the amount of each color stain does not exceed each color threshold, the cleaning process of the light transmissive member 34 is ended (end of FIG. 6).

  In step # 205, the control unit 20 causes the cleaning unit 50 of the exposure unit 30 to clean the surface of the light transmissive member 34. At this time, the control unit 20 does not execute processing related to detection of the current value of the cleaning motor 56.

  In Step # 206, the control unit 20 causes the cleaning unit 50 to start cleaning the surface of the light transmissive member 34, and resets the amount of dirt to 0 (zero). Further, in step # 207, the control unit 20 causes the current detection unit 58 to detect the amount of current flowing through the cleaning motor 56 when the surface of the light transmissive member 34 is cleaned.

  As described above, the control unit 20 of the second embodiment cleans the surface of the light transmissive member 34 by the cleaning unit 50 when the amount of all color stains exceeds the all color threshold value and the amount of each color stain exceeds each color threshold value. The number of times is added by a predetermined number of times (for example, once here).

  As in the first and second embodiments, the image forming apparatus 1 includes the photosensitive drum 11, the exposure unit 30, the cleaning unit 50, the humidity detection unit 26, the dot count unit 24, and the control unit 20. The photosensitive drum 11 is used as an image carrier for forming a toner image. The exposure unit 30 includes a light transmissive member 34 at a light emission portion with respect to the photosensitive drum 11, and performs exposure by irradiating the surface of the photosensitive drum 11 with light. The cleaning unit 50 cleans and removes deposits on the surface of the light transmissive member 34 of the exposure unit 30. The humidity detector 26 detects the humidity of the surrounding environment. The dot count unit 24 measures the number of toner consumption dots in an image printed on paper. The control unit 20 controls operations of the photosensitive drum 11, the exposure unit 30, and the cleaning unit 50. Further, after the print job is finished, the control unit 20 calculates the toner consumption dot number of the print image in one print job output from the dot count unit 24 and the humidity coefficient derived based on the humidity information output from the humidity detection unit 26. When the amount of contamination of the light transmissive member 34 derived by using the calculated value exceeds a predetermined threshold value, the cleaning unit 50 cleans the surface of the light transmissive member 34.

  According to this configuration, it is possible to derive the stain amount of the light transmissive member 34 of the exposure unit 30 corresponding to the number of toner consumption dots in the image printed on the paper and the humidity of the surrounding environment of the image forming apparatus 1. Based on the amount of dirt, the cleaning unit 50 can clean the surface of the light transmissive member 34 at a predetermined timing. Therefore, in the image forming apparatus 1, it is possible to execute a suitable cleaning of the light transmissive member 34 corresponding to the toner consumption amount and the usage environment.

  Then, when the stain amount does not exceed the threshold value, the control unit 20 stores the stain amount in the storage unit 23 in order to add to the stain amount derived after the next print job is completed.

  According to this configuration, when the amount of dirt does not exceed the threshold value and the cleaning unit 50 does not perform cleaning of the surface of the light transmissive member 34, the amount of dirt is reflected in cleaning after the end of the next print job. it can. As a result, it is possible to cause the cleaning unit 50 to clean the surface of the light transmissive member 34 at a suitable timing.

  Further, the image forming apparatus 1 includes a cleaning motor 56 that is a driving unit for driving the cleaning unit, and a current detection unit 58 for detecting the amount of current flowing through the cleaning motor 56. The control unit 20 transmits light again to the cleaning unit 50 when the current value output from the current detection unit 58 exceeds a predetermined threshold value when the cleaning unit 50 performs cleaning of the surface of the light transmissive member 34. The surface of the adhesive member 34 is cleaned.

  According to this configuration, when the deposits on the surface of the light transmissive member 34 cannot be removed by a predetermined number of cleanings (for example, once), it corresponds to the deposits actually remaining on the surface of the light transmissive member 34. Cleaning can be performed. As a result, the cleaning performance for the surface of the light transmissive member 34 can be improved.

  Further, the image forming apparatus 1 includes a display unit 5w that is a notification unit for notifying the user of the operation state. When the cleaning of the surface of the light transmissive member 34 by the cleaning unit 50 that has been repeatedly executed repeatedly reaches a predetermined number of times (for example, three times), the control unit 20 informs the display unit 5w of error information.

  According to this configuration, it is possible to set an upper limit on the number of cleanings that are continuously and repeatedly performed. Therefore, it is possible to suppress the endless cleaning of the surface of the light transmissive member 34 indefinitely. As a result, the image forming apparatus 1 can be preferably operated, and an unintended increase in power consumption and wear of the cleaning member 52 can be prevented.

  Further, the image forming apparatus 1 is an image forming apparatus having a plurality of photosensitive drums 11 corresponding to a plurality of color toners, and the dot count unit 24 is based on the toner of all the plurality of colors regarding the measurement of the number of toner consumption dots. The number of all color dots and the number of each color dot based on the toner of each color are individually measured. When the all-color stain amount derived by calculating using the number of all-color dots of the print image and the humidity coefficient in one print job exceeds a predetermined all-color threshold, When the amount of each color stain derived by calculation using the number of dots of each color of the print image and the humidity coefficient in one print job exceeds a predetermined color threshold value, the light transmissive member 34 is supplied to the cleaning unit 50. Cleaning of the surface of the transparent member 34 is performed, and when the amount of all color stains exceeds the all color threshold value and the amount of each color stain exceeds each color threshold value, the predetermined number of times of cleaning the surface of the light transmissive member 34 by the cleaning unit 50 is determined in advance. Add the number of times (for example, one time).

  According to this configuration, the amount of dirt is derived for each color corresponding to the image forming apparatus that handles toner of a plurality of colors. Accordingly, in the image forming apparatus that consumes a relatively large amount of a specific color, it is possible to cause the cleaning unit 50 to clean the surface of the light transmissive member 34 at a suitable timing.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the first and second embodiments, after the contamination amount exceeds the threshold value, the number of cleanings to be executed before determining whether the current value exceeds the threshold value is set to one and executed until an error is notified. Although the total number of cleanings is 3, the number of cleanings is not limited to the number of times, and other numbers may be set. Similarly, in the second embodiment, the number of cleanings to be added when the amount of all color stains exceeds the all color threshold value and the amount of each color stain exceeds each color threshold value is set to one. The number of times is not limited, and other times may be set.

  In the cleaning unit 50 of the above embodiment, the surface of the four light transmissive members 34 is simultaneously cleaned using one cleaning motor 56, but the four light transmissive properties using four motors. The surface of the member 34 may be individually cleaned. As a result, the cleaning can be performed based on the individual amount of dirt corresponding to each of the four light transmissive members 34, and therefore, the cleaning timing can be further improved.

  The present invention can be used in an image forming apparatus.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Operation panel 5w Display part (notification part)
6 Printing Unit 10 Image Forming Unit 11 Photosensitive Drum 16 Paper Size Detection Unit 20 Control Unit 23 Storage Unit 24 Dot Counting Unit 26 Humidity Detection Unit 30 Exposure Unit 30b Lid 31 Light Source 33 Opening 34 Light Transmissive Member 50 Cleaning Unit 56 Cleaning Motor (drive unit)
58 Current detector

Claims (5)

A photosensitive drum used as an image carrier to form a toner image;
An exposure unit for exposing the surface of the photoconductive drum by irradiating light on the surface of the photoconductive drum having a light transmissive member at a light emitting portion with respect to the photoconductive drum;
A cleaning unit for cleaning and removing deposits on the surface of the light transmissive member of the exposure unit;
A humidity detector that detects the humidity of the surrounding environment;
A dot count unit for measuring the number of toner consumed dots in an image printed on paper,
A control unit for controlling operations of the photosensitive drum, the exposure unit, and the cleaning unit;
With
After the print job is finished, the control unit calculates the toner consumption dot number of the print image in one print job output by the dot count unit and a humidity coefficient derived based on the humidity information output by the humidity detection unit. An image that causes the cleaning unit to perform cleaning of the surface of the light-transmitting member when the amount of dirt of the light-transmitting member that is derived by using the calculated value exceeds a predetermined threshold value. Forming equipment.   2. The control unit according to claim 1, wherein when the stain amount does not exceed the threshold value, the control unit stores the stain amount for addition to the stain amount derived after the end of the next print job. The image forming apparatus described. A driving unit for driving the cleaning unit;
A current detection unit for detecting the amount of current flowing through the drive unit;
With
When the cleaning unit performs cleaning of the surface of the light transmissive member, a current value output from the current detection unit exceeds a predetermined threshold value, and then the cleaning unit is returned to the cleaning unit. The image forming apparatus according to claim 1, wherein the surface of the light transmissive member is cleaned. A notification unit for notifying a user of an operation state of the image forming apparatus;
The said control part makes the said alerting | reporting part alert | report an error information, when the cleaning of the surface of the said light transmissive member by the said cleaning part performed repeatedly repeatedly reaches the predetermined predetermined number of times. Item 4. The image forming apparatus according to Item 3. An image forming apparatus having a plurality of the photosensitive drums corresponding to a plurality of color toners,
Regarding the measurement of the number of toner consumption dots, the dot count unit individually measures the number of all color dots based on the toner of the plurality of colors and the number of each color dot based on the toner of each color,
The control unit, when the amount of all-color stains derived by calculating using the number of all-color dots of the print image and the humidity coefficient in one print job exceeds a predetermined all-color threshold value In addition, when the amount of each color stain derived by calculation using the number of color dots of the print image and the humidity coefficient in a single print job exceeds a predetermined color threshold value, the cleaning unit When the surface of the light transmissive member is cleaned, and the amount of all color stains exceeds the all color threshold value and the amount of each color stain exceeds the color threshold value, the cleaning unit performs the cleaning of the light transmissive member. 5. The image forming apparatus according to claim 1, wherein the number of times of cleaning the surface is added by a predetermined number of times.

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