JP2005215295A - Electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppresses differences in density, color, aspect ratio, etc., among a plurality of images during exposure to the images which are arrayed in a horizontal scanning direction, to prevent dust from adhering to a translucent member of a laser projection window of an optical writing device, and to remove the adhered dust. <P>SOLUTION: There provided an electrophotographic image forming apparatus, which forms an image by forming an electrostatic latent image by exposing a photoreceptor and visualizing by development and transferring the image to image-receiving paper, the electrophotographic image forming apparatus being equipped with an exposure condition setting means of setting exposure conditions in an area to which the image is exposed, according to the position of the area in the horizontal scanning direction when an exposure area on the photoreceptor is divided into a plurality of areas arrayed in the horizontal scanning direction nearly perpendicular to the moving direction of the photoreceptor, and at least two or more areas are exposed to the image. Further, provided is a dustproof mechanism for cleaning the translucent member fitted to the laser projecting window. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic image forming apparatus and a dustproof mechanism thereof, and in particular, an electrophotographic method having a function of eliminating density unevenness, color unevenness, or image distortion due to lens aberration due to an exposure position in the main scanning direction. The present invention relates to an image forming apparatus and a dustproof mechanism for cleaning a transparent member of a laser emission window of an optical writing apparatus that exposes a photosensitive member of an electrophotographic image forming apparatus.

  Conventionally, an electrostatic latent image is formed on an electrostatic latent image carrier (photoreceptor) using a photoconductive phenomenon, and colored charged fine particles (toner) are attached to the electrostatic latent image by electrostatic force. An electrophotographic system for forming a visible image is known.

  In an electrophotographic image forming apparatus to which this is applied, the photosensitive member is uniformly charged with a charger, the charged photosensitive member is exposed with a laser beam with an optical writing device, and an electrostatic latent image is formed on the photosensitive member. Form. The electrostatic latent image is visualized as a toner image by toner of each color by a developing device of each color, and the visualized toner image is transferred as a toner image onto a recording sheet via an intermediate transfer member, fixed, and output. The

  FIG. 26 shows a simplified manner of forming an electrostatic latent image on the photosensitive member by the optical writing device. As shown in FIG. 26, the optical writing apparatus includes a laser diode 201 that emits a laser beam, a polygon mirror (rotating polygonal mirror) 202 that reflects the laser beam while rotating, and other optical elements such as lenses and mirrors that are not shown. Consists of systems. The photosensitive drum 203 is scanned in the main scanning direction indicated by an arrow M in the figure by a laser beam reflected by the polygon mirror 202 and the direction of which is changed by the rotation of the polygon mirror 202, and indicated by an arrow S in the figure. By rotating the photosensitive drum 203 as described above, scanning in the sub-scanning direction orthogonal to the main scanning direction forms a two-dimensional image on the surface.

  At this time, even if the conventional commercial photographic printer has an exposure mechanism in a wide width region, when recording an image on a narrow width recording paper, it is necessary to record in a single row on the narrow width recording paper. In addition, the photosensitive member is exposed to light and the efficiency is poor. In addition, when an image is arranged and exposed on a photoconductor so that the image is cut after being arranged in a plurality of rows on a wide-width recording paper, the density and color tone differ depending on the exposure position in the main scanning direction. There was a problem of uneven density and uneven color.

  In contrast to this, for example, the toner adhesion amount of the toner image formed on the transfer unit is detected by an infrared sensor, and the image density is adjusted by correcting the light amount fluctuation of the exposure optical system based on the detected toner adhesion amount. Thus, there is known one that stabilizes the adjustment of the image density (see, for example, Patent Document 1).

  Further, in a rotary drum type ink jet printer that records an image by ejecting an ink jet toward a recording drum that rotates by winding paper, the density measuring means is moved to a plurality of predetermined positions of the print image to measure the density. A device having a mechanism and correcting the gradation and color of an image based on the density measurement data is known (for example, see Patent Document 2).

  Further, in a heat developing apparatus having a drum that rotates while holding the photosensitive heat developing material on the outer peripheral surface, the image signal is corrected by uneven temperature of the drum and shading unevenness of the deflection optical system that exposes the photosensitive heat developing material. Thus, there is known one that suppresses the occurrence of density unevenness in an image and stabilizes the density (see, for example, Patent Document 3).

  In the electrophotographic image forming apparatus, as shown in FIG. 27, the laser beam reflected by the polygon mirror 202 forms an image on the surface of the photosensitive drum 203 via the scanning lens 204. At this time, if the focal length of the scanning lens 204 is f and the angle of view of the scanning lens 204 is θ, the image height y on the image plane has a characteristic of y = f × θ. Therefore, there is a deviation (aberration Δy) from the original image height. FIG. 28 shows the relationship between this angle of view and the ratio of aberration Δy to the original image height (image distortion). As shown in FIG. 28, the aberration Δy (ratio) is 0 at the center of the scanning lens 204, but image distortion increases as the angle of view (ratio) increases.

  Further, since the polygon mirror 202 rotates at an equiangular speed, when the pixel clock frequency is constant, the width of the image increases as the angle of view increases. Therefore, in such a laser scanning system of an electrophotographic image forming apparatus, when a plurality of images are arranged and exposed in the main scanning direction, the width of the image exposed on the outside increases, and the aspect ratio differs when compared with the same image. The image is completed. Therefore, as a result, the subject in the image appears to be fat, or when cutting before output, some of the adjacent images are mixed, or when a white edge photo image is printed, the white edge There is a possibility that the width of the left and right becomes non-uniform.

  For example, in a scanning system having a maximum scanning width of 12 inches (304.8 mm) and aberration characteristics (fθ characteristics) as shown in FIG. 28, three rows of 89 mm wide images are arranged, and the left image (image area A). Uses an angle of view of −87.5% to −29.2%, the central image (image area B) uses an angle of view of −29.2% to + 29.2%, and the right image (image area C). ) Consider a case where exposure is performed using an angle of view of + 29.2% to + 87.5%.

  At this time, as shown in FIG. 29, the image width of each print is 89.1 mm in the central image area B, 90.1 mm in the image areas A and C on the left and right sides, and 1 mm in width. , A difference of + 1.11% occurs in the ratio. In photographic print applications, this aspect ratio is required to be suppressed to at least less than 0.5%.

  In order to eliminate such image distortion, for example, in an optical scanning device that scans a surface to be scanned without using an fθ lens by deflecting modulated light from a semiconductor laser with a polygon mirror, An image scanning clock whose frequency changes continuously according to the scanning speed of the main scanning is generated, and a signal that changes stepwise in proportion to the change of the scanning speed is obtained, and this signal is modulated, There is known a technique in which a semiconductor laser is driven to perform optical writing scanning to remove distortion and density unevenness in a recorded image (see, for example, Patent Document 4).

  Further, it is known that the fθ correction is performed by changing the number of pulses of the print clock for outputting one dot of the image data in accordance with the output area to the photosensitive member surface in the main scanning direction. (For example, patent document 5).

  In addition, as described above, the electrophotographic method uses an optical writing device to form an electrostatic latent image on an electrostatic latent image carrier (photoconductor) using a photoconductive phenomenon, and is further colored charged fine particles. A visible image is formed by adhering (toner) to an electrostatic latent image with electrostatic force. The optical writing device is hermetically sealed by a housing and a cover so that dust does not enter inside, and a laser emission window for emitting a laser beam is closed by a transparent member such as glass or transparent plastic. .

  In such an electrophotographic system, toner is scattered or dust brought in by the cooling air of the image receiving paper or the device is scattered in the apparatus, and the scattered dust is transferred to the optical writing device (laser beam). It tends to adhere to a transparent member such as glass of the laser exit window of the scanning system.

  When such dust adheres to the transparent member of the laser exit window of the optical writing device, the laser beam passing therethrough is blocked by the attached dust, or the amount of light is reduced. For this reason, if exposure is performed in this state, the laser beam is blocked at a fixed position, or the amount of transmitted light is reduced, and vertical stripes in which only the density is reduced in the conveying direction of the image receiving paper are generated. Furthermore, if this is over a long period of time, the transmissive member of the laser emission window becomes cloudy, and the emitted laser beam is scattered and a blurred image is output.

  Although it depends on the beam spot diameter on the photosensitive member and the distance between the photosensitive member and the optical writing device, generally, the spot diameter on the laser emission window is often less than 1 mm. Further, according to the photographic image quality standard, even if dust having a size of about 10 μm to 20 μm adheres to the laser emission window, it is recognized as a visible image defect. Therefore, even if such vertical streak image defects due to dust adhesion are acceptable image defects in general color copy printer applications, they are acceptable when used in photographic printer applications. There are many things that cannot be done.

  That is, unlike when used as a general color printer / copier, particularly when used as a high-quality photographic printer for business use, for example, 1000 to 2000 sheets per hour are large, and the number of print processes is unmanned. In some cases, printing may continue throughout the day, even if image defects occur, and there may be cases where maintenance is not performed at all.Further, because the amount of processing is large, the frequency of dust adhesion increases, Further, as described above, in the case of photographic prints, since the level of image quality specifications is high, it is desirable that dust adhere to the laser emission window and prevent image defects.

  In conventional electrophotographic copying printers, when the image defect is confirmed by the output print, the user can wipe off dust attached to the laser emission window by a manual mechanism (manual operation) or a toner unit. There has been proposed a structure in which the laser emission window is automatically wiped in conjunction with the attachment / detachment of the door or the opening / closing of a door that can be freely opened and closed.

  For example, a magazine in which a cleaning unit, a toner cartridge, and charging means are integrated is detachably attached to the apparatus main body, and dust-proof glass attached to the front surface of the optical writing means is slidably brought into contact with the magazine when the magazine is attached and removed for cleaning. A cleaning unit is provided, and when the user manually replaces the magazine, the cleaning unit can naturally clean the dustproof glass (see, for example, Patent Document 6).

  In addition, a dustproof glass cleaning member that is supported by a rail and moves while being in sliding contact with the dustproof glass is attached to a paper feed cassette that can be taken in and out of the apparatus main body. There is known one that can clean dust-proof glass while moving along a rail (for example, see Patent Document 7).

In addition, when a cover member that can be opened and closed is provided on the outside of the dust-proof glass of the optical writing device, and the cover member is opened, the upper part of the dust-proof glass is exposed, and dust adhering to the dust-proof glass is removed. (For example, see Patent Document 8).
JP-A-5-11562 JP 11-326056 A JP 2000-292897 A Japanese Examined Patent Publication No. 6-14663 Japanese Patent No. 2821354 JP 7-128959 A JP 2002-333802 A JP 2001-33723 A

  However, in the prior art, in the electrophotographic image forming apparatus, due to the transmittance of the optical components of the scanning optical system, the non-uniformity of the exposure amount due to uneven reflectance, or the non-uniform temperature distribution of the fixing device due to the environmental temperature It is still insufficient to solve the problem of density unevenness and color unevenness depending on the exposure position in the main scanning direction, resulting in density unevenness and color unevenness. Further, as described above, in the case of a photographic printer, this aspect ratio is at least 0.5% for the problem that due to lens aberration, the width of the image exposed outside in the main scanning direction becomes wider and the aspect ratio becomes different. Although it is required to suppress the lens to less than 0.5%, the fθ property is suppressed to less than 0.5% while suppressing other aberrations of the lens such as field curvature and chromatic aberration to a level satisfying the photographic image quality with a limited number of lens balls. It is difficult. Further, as in the prior art, it is difficult to continuously change the pixel clock on one line in terms of the complexity of the mechanism, stability and accuracy.

  On the other hand, all of the conventional dustproof glass cleaning systems described above are manually performed by humans, and the timing of cleaning is limited to when a magazine or paper cassette is put in and out. Less frequently. Therefore, when an electrophotographic image forming apparatus is used as a professional photographic printer, if an image defect is recognized at the stage of printing a large amount, loss of image receiving paper output up to that point and time will be enormous. Since there are cases where printing is done unattended for a long time, there is a problem that there are many cases where it is not possible to check the printing one by one or when cleaning is infrequent only at the time of cartridge replacement.

  The present invention has been made in view of such circumstances. When a single wide recording area is divided into a plurality of areas arranged in the main scanning direction and a plurality of images are exposed, the main scanning direction is obtained. It is a first object of the present invention to provide an electrophotographic image forming apparatus that can suppress differences in density, color, aspect ratio, and the like between images arranged side by side.

  The present invention also provides a dustproof mechanism for an electrophotographic image forming apparatus capable of automatically removing dust adhering to a transparent member of a laser exit window of an optical writing device at a specified arbitrary timing. The second object is to provide the above.

  In order to achieve the first object, according to the first aspect of the present invention, there is provided an electrophotographic method in which a photosensitive member is exposed to form an electrostatic latent image, developed, visualized, and transferred onto an image receiving paper to form an image. In the image forming apparatus, the exposure area on the photosensitive member is divided into a plurality of regions arranged in a main scanning direction substantially orthogonal to the moving direction of the photosensitive member, and an image is exposed to at least two or more of the regions. In this case, there is provided an electrophotographic image forming apparatus comprising exposure condition setting means for setting an exposure condition in an area where the image is exposed in accordance with a position of the area in the main scanning direction.

  Accordingly, a plurality of images can be exposed and recorded in the main scanning direction, so that the print processing capability can be improved and the apparatus can be used efficiently, and uneven exposure in the main scanning direction can be suppressed.

  The exposure condition setting means optimizes the LUT for setting the density for exposing the area according to the position in the main scanning direction of the area where the image is exposed, thereby correcting density unevenness due to the position in the main scanning direction. It is characterized by correcting. This makes it possible to correct differences in image density and color, particularly in the main scanning direction.

  The LUT is generated by outputting a LUT creation chart and measuring the density. Further, it is preferable that the LUT is automatically created at the head of the print process for each print order. Furthermore, it is preferable that the LUT can be created at any time.

  Further, the exposure condition setting means sets a pixel clock frequency for exposing an image in an area where the image is exposed, for each image in the main scanning direction corresponding to a lens aberration characteristic of an exposure optical system for exposing the photosensitive member. The difference in the aspect ratio of the image in the main scanning direction due to the lens aberration is corrected by setting according to the position of the region.

  Thereby, the difference in the aspect ratio of the image due to the lens aberration of the exposure optical system in the main scanning direction can be suppressed.

  The exposure condition setting means optimizes a LUT for setting a density for exposing the area according to a position in the main scanning direction of the area where the image is exposed, and in the area where the image is exposed. The pixel clock frequency for exposing the image is set according to the position of each image area in the main scanning direction corresponding to the lens aberration characteristic of the exposure optical system for exposing the photosensitive member.

  Thereby, the difference in aspect ratio due to density unevenness in the main scanning direction and lens aberration can be eliminated at the same time.

  Similarly, in order to achieve the second object, the invention according to claim 8 is the transmission attached to the laser emission window provided on the front surface of the optical writing device of the electrophotographic image forming apparatus. A dustproof mechanism for cleaning a member, the cleaning means for cleaning the surface of the permeable member, the drive means for driving the cleaning means to perform a cleaning operation on the permeable member, and the drive And a dustproof mechanism for an electrophotographic image forming apparatus, characterized in that the transparent member is automatically cleaned.

  Thus, the user can automatically clean the transmissive member without being aware of the cleaning of the transmissive member of the laser emission window, and can prevent dust from adhering to the transmissive member. It is possible to greatly reduce the occurrence of the entered image defect.

  Further, the cleaning means is cleaned by wiping the surface of the permeable member while contacting the permeable member and moving along the permeable member by the driving means. By wiping the surface in this way, the dust adhering to the surface of the permeable member can be reliably removed.

  Moreover, it is preferable that the said drive means moves the said cleaning means along the said permeable member by a wire and motor operation | movement. Thereby, automatic cleaning operation | movement is realizable with a simple apparatus structure.

  The dust-proof mechanism of the electrophotographic image forming apparatus of the present invention preferably further includes a liquid filling unit that fills a portion where the cleaning unit contacts the permeable member with a volatile liquid. This further facilitates removal of dust attached to the surface of the permeable member.

  Moreover, it is preferable that the part which contacts the said permeable member of the said cleaning means is exchangeable. In this way, by replacing the contact portion of the cleaning means that has been soiled by wiping, wiping can always be performed with clean cleaning means.

  Further, the control means controls the driving means so that the cleaning means performs a cleaning operation on the transparent member before the optical writing device exposes the first image for one print order. Features. Thus, by performing the cleaning operation every time processing for a new order is started, exposure can be performed with the optical writing device that is always in a clean state.

  The control means controls the drive means so that the cleaning means performs a cleaning operation on the transmissive member whenever the optical writing device exposes a predetermined number of images. According to this, even when the number of processed images in one order is large, the optical writing apparatus can be kept clean by appropriately performing the cleaning operation.

  The control means controls the drive means so that the cleaning means performs a cleaning operation on the permeable member whenever a predetermined time elapses. According to this, regardless of the order, the optical writing device can always be kept clean by appropriately performing the cleaning operation.

  Further, the control means controls the drive means so that the cleaning means performs a cleaning operation on the permeable member at an arbitrary designated timing. According to this, even when an image defect has occurred when the designated cleaning timing has not yet been met, it can be dealt with immediately and the optical writing apparatus can be cleaned.

  The dust-proof mechanism of the electrophotographic image forming apparatus of the present invention further includes a cleaning timing designating unit that designates a cleaning timing at which the cleaning unit performs a cleaning operation on the permeable member, and the cleaning timing designating unit includes: As the cleaning timing, before the optical writing device exposes the first image for one print order, every time the optical writing device exposes a predetermined number of images, every predetermined time, and any time point Any one of them can be specified.

  As a result, it is possible to perform automatic cleaning repeatedly only by specifying the cleaning timing, and there is no restriction on the timing of wiping as in the case of manual wiping. Printing can be performed without worrying about the occurrence of image defects, and the quality of the output print can be maintained high.

  Similarly, in order to achieve the second object, the invention according to claim 18 is characterized in that the transparency attached to the laser emission window provided on the front surface of the optical writing device of the electrophotographic image forming apparatus. A dust-proof method for cleaning a member, and when there is a print instruction, the transparent member is automatically cleaned prior to the exposure of the first image for each print order. The present invention provides a dustproof method for an electrophotographic image forming apparatus.

  Thereby, it is possible to always perform exposure with a clean optical writing apparatus by always automatically cleaning before starting processing for a new order.

  Similarly, in order to achieve the second object, according to the nineteenth aspect of the present invention, there is provided a transparency attached to a laser emission window provided in front of an optical writing device of an electrophotographic image forming apparatus. A dust-proof method for cleaning a member, and when there is a print instruction, the number of prints exposed is counted, and the cumulative number of prints after the previous cleaning of the transparent member is a predetermined number When the value reaches the above, a dust-proof method for an electrophotographic image forming apparatus is provided in which the transparent member is automatically cleaned.

  According to this, it is possible to always keep the optical writing device clean by appropriately automatically cleaning each time a predetermined number of sheets are processed.

  Similarly, in order to achieve the second object, the invention according to claim 20 is characterized in that the transparency attached to the laser emission window provided on the front surface of the optical writing device of the electrophotographic image forming apparatus. A dust-proof method for cleaning a member, and when there is a print instruction, if the accumulated time after the previous cleaning of the permeable member reaches a predetermined time given in advance, the permeable member is cleaned. The present invention provides a dustproof method for an electrophotographic image forming apparatus, which is characterized by automatically performing the above.

  According to this, the cleaning of the optical writing device can always be kept clean by appropriately automatically cleaning each time a predetermined time elapses.

  The permeable member is preferably cleaned by wiping the surface of the permeable member while bringing a cleaning means into contact with and moving the surface of the permeable member.

  Similarly, in order to achieve the second object, the invention according to claim 22 is characterized in that the transparency attached to the laser emission window provided on the front surface of the optical writing device of the electrophotographic image forming apparatus. A dust-proof mechanism for preventing dust from adhering to a member, covering a casing around a laser emission window of the optical writing device so as to be sealed, and a laser beam emitted from the laser emission window A duct having an opening for passing through, an openable / closable shutter attached to the opening of the duct, a fan for sending air into the duct, and in the air sent into the duct by the fan A dust-proof filter for removing dust, and the fan sends clean air through the dust-proof filter into the duct to pressurize the duct. The air so as to exhaust by opening the shutter unit, provides a dustproof mechanism of electrophotographic image forming apparatus characterized by preventing the adhesion of dirt dust into the transparent member.

  In this way, the periphery of the laser emission window is sealed with a duct, and the air in the sealed part is pressurized so that dust or the like does not enter from the outside through the open shutter part, and the air in the sealed part in the duct is cleaned. It is possible to prevent dust from adhering to the transparent member of the laser emission window.

  In the dust-proof mechanism of the electrophotographic image forming apparatus according to the present invention, the shutter unit opens and closes only when the optical writing device performs an optical writing operation. By opening the shutter portion only at the time of optical writing and closing the shutter portion at other times, it is possible to efficiently prevent dust from adhering to the transparent member of the laser emission window.

  In addition, when the optical writing device performs an optical writing operation, it is preferable that the shutter is opened after the fan works and pressurizes the inside of the duct. By opening the shutter part after pressurizing the inside of the duct in this way, it is possible to prevent dust from entering the duct when the shutter part is opened.

  The dust filter has a double structure, and the outer dust filter has a higher dust collection rate than the inner dust filter and is preferably replaceable. As a result, the air taken in from the fan can be sufficiently cleaned, and dust does not enter the duct when the dustproof filter is replaced.

  In addition, it is preferable that an air intake port of a fan for sending air into the duct is directed to a side opposite to a side where a laser beam is emitted from the optical writing device. Moreover, it is preferable that the space between the air inlet side and the side from which the laser beam is emitted is shielded so that dust does not easily move. Thereby, intrusion of dust from the air inlet can be reduced.

  Moreover, it is preferable that a lid that can be opened and closed is installed on the front surface of the air inlet. Thus, when the optical writing operation is not performed, the fan is not operated, and the front of the air intake port of the fan is covered with the lid, so that dust can be prevented from entering the duct.

  As described above, according to the electrophotographic image forming apparatus of the present invention, a plurality of images (frames) are arranged in the main scanning direction and exposed and processed in multiple rows, thereby improving the print processing capability and improving the device performance. In addition to achieving efficient use, the LUT is switched at each print position of the multi-row, and the exposure is performed by setting individually, so that differences in gradation and color depending on the position in the main scanning direction can be suppressed. . Furthermore, since the pixel clock frequency is switched at each position of the multi-column and individually set for exposure, it is possible to suppress the difference in aspect ratio depending on the position in the main scanning direction.

  Further, according to the dustproof mechanism of the electrophotographic image forming apparatus according to the present invention, the dust adhering to the transparent member of the laser emission window of the optical writing device is automatically removed at a specified arbitrary timing. It becomes possible to do.

  Furthermore, according to the dust-proof mechanism of the electrophotographic image forming apparatus according to the present invention, the inside of the duct in which the periphery of the laser emission window is sealed is automatically cleaned every time the optical writing apparatus performs the optical writing operation. The air can be pressurized to prevent the dust from entering the duct and prevent the dust from adhering to the transparent member of the laser emission window.

  Hereinafter, an electrophotographic image forming apparatus and a dustproof mechanism thereof according to the present invention will be described in detail with reference to the accompanying drawings.

  First, an electrophotographic image forming apparatus according to a first embodiment of the present invention will be described.

  The electrophotographic image forming apparatus according to this embodiment divides a wide exposure area into a plurality of areas in the main scanning direction, and exposes an image in each area, thereby exposing a plurality of images side by side in the main scanning direction. By fixing the exposure conditions in each area according to the position of each area in the main scanning direction, it is possible to fix the unevenness of the exposure amount due to the transmittance and reflectance unevenness of the optical components of the scanning optical system or the environmental temperature. In addition to correcting unevenness in color density and gradation in the main scanning direction due to the temperature distribution non-uniformity, the difference in aspect ratio between the images in the main scanning direction due to lens aberration is corrected. As will be described in detail later, switching of exposure conditions in each region in the main scanning direction is performed by setting, for example, a density LUT (lookup table) and a pixel frequency for recording each pixel for each region. Is called.

  FIG. 1 is a conceptual diagram schematically showing an electrophotographic image forming apparatus according to a first embodiment of the present invention. As shown in FIG. 1, an electrophotographic image forming apparatus 100 according to this embodiment includes an image input / operation unit 110 and an image output unit 120. Basically, the image input / operation unit 110 should be printed. The image data is input and various instructions are input. The image output unit 120 outputs the input image data as a print.

  The image input / operation unit 110 includes an image input unit 112, an operation unit 114, an input unit control unit 116, and a monitor 118. The image output unit 120 includes an optical writing unit 122, a printer output unit 124, and an output unit control unit 128.

  The image input unit 112 captures image data as digital image data. There is no restriction | limiting in particular as digital image data used here, According to the objective, it can select suitably. For example, image data read by a film scanner from a film image taken by a film camera, image data obtained by performing additional processing on the taken image data, image data taken by a digital still camera (DSC), digital video Image data captured from (DV), image data read from a reflective original by a reflective scanner, image data input to a receiving device such as a personal computer, or from a portable information terminal, e-mail, telephone line or network server The input image data and the like are preferably exemplified.

  The operation unit 114 is specifically composed of a mouse and a keyboard attached to a personal computer, and the user gives various instructions to the image forming apparatus. And instructions for finishing prints are input.

  Specifically, the input unit control unit 116 is configured by a personal computer, and controls each unit of the image input / operation unit 110. Specifically, the monitor 118 is a display for displaying various information connected to a personal computer, and displays a reference screen for displaying input image data or inputting various instructions from the operation unit 114. .

  The optical writing unit 122 forms an electrostatic latent image on the photosensitive member by the optical writing device, and the printer output unit 124 visualizes and transfers the electrostatic latent image on the electrophotographic image receiving paper, This is output as a finished print.

  The output unit control unit 128 controls each unit of the image output unit 120. For example, the output unit control unit 128 receives digital image data input from the image input unit 112 and subjected to image processing via the input unit control unit 116, and receives the optical image data. The data is transferred to the writing unit 122 and the optical writing unit 122 is controlled to record an electrostatic latent image, or the printer output unit 124 is controlled to output a print. Further, the output unit control unit 128 divides the exposure area described above into a plurality of areas in the main scanning direction, sets the LUT and the pixel frequency for each area, and performs optical writing according to the set exposure conditions. The unit 122 is controlled.

  In addition, the image output unit 120 is provided with a sorter 130, which sorts and stores the final output prints.

  The electrophotographic image forming apparatus of the present invention is conceptually configured as described above, but a more specific apparatus configuration is shown in FIG. 2, and the operation of each part will be described in detail below based on this. To do.

  FIG. 2 shows the configuration of the electrophotographic image forming apparatus of this embodiment in more detail. FIG. 2 shows in detail the apparatus configuration of the image output unit 120 of the electrophotographic image forming apparatus 100 conceptually shown in FIG.

  An electrophotographic image forming apparatus 10 shown in FIG. 2 includes an electrostatic latent image forming unit, a toner image forming unit, an image forming unit 12 as a toner image forming unit, a roll cutter 14 as a roll cutting unit, and a primary fixing unit. Heating and pressing roller 16, belt fixing device 18 as secondary fixing means for smoothing gloss, XY cutter 20 for cutting prints in the vertical and horizontal directions, roll paper 22 which is a roll-type electrophotographic image receiving paper, back surface A print head 24 for printing and a sorter 26 for sorting and storing output prints are provided. Further, if necessary, a sheet cassette 28 for loading various types and sizes of cut sheets may be provided.

  The image forming unit 12 mainly includes an optical writing device (ROS) 30, a photosensitive drum 32, a developing device 34, an intermediate transfer belt 36, and the like. The optical writing device 30 exposes a digital image that has been input and subjected to image processing as digital image data to the surface of the charged photosensitive drum 32 imagewise to form an electrostatic latent image. This is an image forming unit and corresponds to the optical writing unit 122 described above. The optical writing device 30 emits a laser beam modulated by an image signal, and scans the photosensitive drum 32 by a rotating polygon mirror (not shown). The emitted laser beam is reflected by a mirror 39. The optical path is folded back and imaged on the photosensitive drum 32.

  The photosensitive drum 32 is an electrostatic latent image carrier on which an electrostatic latent image is formed. The photosensitive drum 32 is uniformly charged by the charger 40, and an electrostatic latent image is formed on the surface by exposure from the optical writing device 30. The developing device 34 develops a digital image (electrostatic latent image) formed on the photosensitive drum 32 as a toner image with toner, and constitutes a toner image forming unit. In other words, the electrostatic latent image formed on the photosensitive drum 32 is developed by supplying toners of Y (yellow), M (magenta), C (cyan), and K (black) from the developing device 34. The toner image is a visible image.

  The intermediate transfer belt 36 receives the transfer (primary transfer) of the toner image formed on the photosensitive drum 32 by the voltage applied by the primary transfer roller 42, and this is transferred to the electrophotographic image receiving paper by the secondary transfer roller 44. A toner image is formed on the image receiving paper P by transferring (secondary transfer) to P (hereinafter simply referred to as image receiving paper P), and constitutes a toner image forming means.

  The residual toner on the photosensitive drum 32 is removed by a cleaning device 46, and the charge on the photosensitive drum 32 is temporarily removed by a static elimination lamp. The image receiving paper P on which the toner image is formed is conveyed to the fixing means side by the belt conveyor 15 and is fixed by the heating and pressing roller 16 as the primary fixing means and the belt fixing device 18 as the secondary fixing means. It has become.

  In addition to this, the electrophotographic image forming apparatus 10 of the present embodiment has a mechanism for correcting color density unevenness and gradation differences in the main scanning direction, and an aspect ratio between the images in the main scanning direction due to lens aberration. A mechanism for correcting the difference is provided.

  As a mechanism for correcting density unevenness in the main scanning direction, as will be described in detail later, means for reading an LUT creation chart that is output to optimize the LUT applied in each area obtained by dividing the exposure area in the main scanning direction As a density meter 50, a density measurement result of the chart by the density meter 50 is received and an LUT is created, the created LUT is stored in the LUT memory 54, and the optical writing device 30 is controlled using this LUT 52 exists. The control unit 52 corresponds to the output unit control unit 128 of FIG.

  The control unit 52 also modulates the clock signal input from the clock signal generating means 56 as a mechanism for correcting the difference in aspect ratio between the images in the main scanning direction, and in each region according to the position in the main scanning direction. The optical writing device 30 is controlled by switching the pixel frequency.

  Here, a normal print creation operation other than the correction operation of the electrophotographic image forming apparatus 10 will be briefly described.

  The sheet-shaped image receiving paper P pulled out from the roll paper 22 by the transport roll and cut to a predetermined length by the roll cutter 14 is transported by a number of transport rollers provided in the transport path, and predetermined content is printed on the back surface by the print head 24. Is done. At this time, cut sheets that are cut in advance and loaded in the sheet cassette 28 may be used.

  Thereafter, the image receiving paper P is conveyed to the image forming unit 12. In the image forming unit 12, an electrostatic latent image is formed on the photosensitive drum 32 by the optical writing device 30 according to the image data, and the toner image formed by the developing device 34 is transferred to the intermediate transfer belt 36. . The toner image on the intermediate transfer belt 36 is transferred onto the image receiving paper P as a toner image.

  The image receiving paper P on which the toner image is formed is conveyed by the belt conveyor 15 to the side of the heating and pressing roller 16 as the primary fixing means, where heating and pressing are performed. Thereafter, the toner is conveyed to a belt fixing device 18 as a secondary fixing unit, and smooth glossy processing is performed. The belt fixing device 18 includes a heating roller 18a, a pressure roller 18b, a mirror belt 18c, a peeling roller 18d, and a cooling device 19, and smoothes and glosses the toner image on the image receiving paper P. Finally, it is cut into a predetermined size by the XY cutter 20 according to the print, and is accumulated in the sorter 26.

  Here, from the viewpoint of print creation efficiency, a case will be considered in which a plurality of images are arranged and exposed in the main scanning direction, the plurality of images are transferred and fixed on the image receiving paper, and then cut (cut) and output.

  For example, as shown in FIG. 3, images are recorded as an image A and an image B on a sheet-like image receiving paper 60 in the main scanning direction orthogonal to the conveying direction. Hereinafter, while conveying the sheet-shaped image receiving paper 60, two rows of images are arranged and recorded, such as an image C and an image D, and an image E and an image F, respectively. Thereafter, the image is fixed and cut by the cutter 20, and the images A, B, C, D, E, and F are output as separate rose prints 61.

  At this time, as described above, since the density and color vary depending on the position in the main scanning direction, the exposure area is divided into a plurality of areas in the main scanning direction to correct this, and the exposure condition is switched in each area. Like that. For example, the exposure area is divided into three in the main scanning direction, and an optimized LUT is set for each area. This LUT is preferably created prior to printing.

  A method for creating an LUT and a method for using the LUT will be described with reference to FIGS. FIG. 4 is a schematic diagram illustrating a method for creating and using an LUT, and FIG. 5 is a flowchart illustrating an example of a method for creating an LUT.

  First, in step S100 of FIG. 5, the control unit 52 takes in test chart image data. For example, the test chart image data may be stored in advance in a predetermined memory and taken in from here. In the next step S102, the control unit 52 displays a preset LUT indicating the relationship between the image data and the modulation signal at the time of exposure recording according to the type of the image receiving paper 60 on which the test chart image is exposed and recorded. The test chart image data is converted into a modulation signal, the optical writing device 30 is controlled by this modulation signal, and the test chart image is exposed and recorded on the image receiving paper 60. The test chart (LUT) as shown in FIG. A creation chart 62 is created (corrected).

  A test chart 62 as shown in FIG. 4 is created for each color of cyan (C), magenta (M), yellow (Y), and black (K). That is, the test chart 62 for each color, for example, as shown in FIG. 4, divides the exposure area into three areas, area A, area B, and area C, in the main scanning direction, and the density of the color for each area. It consists of patches that change in steps. The test chart 62 exposed and recorded on the image receiving paper 60 is output after fixing.

  In step S104, the density of each patch of the output test chart 62 is measured by the densitometer 50. The densitometer 50 measures the density of each patch of the test chart 62, and the measured density value is sent to the control unit 52.

  In the next step S106, the control unit 52 estimates the logarithmic exposure amount corresponding to the target density value based on the density measurement value of each patch of the test chart 62. This logarithmic exposure amount represents the logarithmic exposure amount necessary for color development of the image receiving paper 60 currently set in the electrophotographic image forming apparatus 10 to a target density. An estimation calculation is performed using the logarithmic value of the exposure amount when the test chart 62 is created.

  In the next step S108, the control unit 52 calculates a correction coefficient for correcting the LUT according to the log exposure amount estimated now. An initial value is set in advance for the correction coefficient. In the next step S110, it is determined whether or not the correction coefficient just calculated is within a predetermined range representing a preset normal value.

  If it is determined in step S110 that the calculated correction coefficient is not within the predetermined range, the process proceeds to step S112, and the correction coefficient is set to an initial value. If it is determined that the calculated correction coefficient is within the predetermined range, in step S114, the control unit 52 corrects the conversion characteristics of the LUT using the correction coefficient to obtain the image data and this. An LUT 63 as shown in FIG. 4 is created for each color, showing the correspondence with the modulation signal corresponding to the logarithmic exposure required to develop the target density on the image receiving paper 60.

  At this time, as the correspondence between the logarithmic exposure amount and the modulation signal, a value measured in advance and stored in the memory may be used. For example, a halfway is present in the optical path of the laser beam emitted from the optical writing device 30. A mirror may be inserted to split a part of the beam, and this may be measured by a light quantity measuring device to determine the relationship between the modulation signal and the logarithmic exposure amount on the image receiving paper 60 by the optical writing device 30. .

  In step S116, it is determined whether the created LUT 63 is OK. For example, if no abnormality such as the correction coefficient being out of the predetermined range has occurred in the processing after step S108, the LUT 63 is OK, the LUT creation processing is terminated, and if not, Returning to step S102, the LUT creation processing after step S102 is repeated again.

This LUT 63 is, for each area A, B, C, for each color of cyan (C), magenta (M), yellow (Y), black (K), for example, a cyan LUT (C _A ) in area A. , Magenta LUT (M _A ), yellow LUT (Y _A ), and black LUT (K _A ). The created LUT 63 is stored in the LUT memory 54.

When the image is actually exposed in three rows in the main scanning direction, the control unit 52 calls the LUT from the LUT memory 54 and controls the optical writing device 30 using the LUT to perform exposure. At this time, as shown in FIG. 4, the images A ₁ , A ₂ , and A ₃ recorded (exposed) in the area _A are used by the LUTC _A , M _A , Y _A , and K _A set for the area A. For the images B ₁ , B ₂ , and B ₃ recorded (exposed) in the area B, the LUTC _B , M _B , Y _B , and K _B set for the area _B are used, and the same applies to the area C. is there. In this manner, as shown in FIG. 4, three rows are arranged in the main scanning direction, and an image 64 created using the LUT 63 optimized in each of the areas A, B, and C is obtained. Since the LUT 63 is optimized so as to correct the density unevenness at the position in each of the areas A, B, and C, the image 64 created using this is an image having no density unevenness.

  The output and reading of the LUT creation chart for creating this LUT can be automatically performed at the head of each print order, and the result can be set to be reflected in each image exposure. Alternatively, a message that prompts the user to set the LUT only when the system is started or when the temperature or humidity has changed more than a certain level since the last time the LUT was created, without being set for each order. The user may create the LUT manually instead of automatically.

Further, the number of divisions of the LUT area is not particularly limited. For example, when the LUT is set for each print order, the pattern of the number of divisions of the image exposed in the main scanning direction in the order print immediately after the LUT is set. Create with. For example, as shown in FIG. 6, when recording an image 65 such as images A ₁ , B ₁ , C _1, etc. arranged in three rows in the main scanning direction, for example, the central images B ₁ , B ₂ , B ₃ Even when the width of the image is narrower than other images A ₁ , C _1, etc., when three images are exposed side by side, LUTs 66 corresponding to the three areas A, B, C are created.

  Further, when the LUT is created when the system is started or periodically, as shown in FIG. 7, the LUT 67 in which the area is divided into four in the main scanning direction and set correspondingly is divided into three similarly. Like the LUT 68 set as described above or the LUT 69 set as divided into two, a pattern having the possible number of divisions may be created from the width of the recording medium and the minimum value of the image width that can be printed. By creating LUTs with various patterns in this way and using the LUTs in accordance with the number of print divisions, it is possible to cope finely and the image quality is improved accordingly. However, a large number of LUTs 67, 68, and 69 (for each color) must be held in the LUT memory 54, and there is a problem that the burden on the system is large.

  Therefore, when a large number of LUTs cannot be set, the divided area (LUT area) is fixed to three areas A, B, and C, for example, as shown in FIG. LUT (A) may be associated with LUT (B) for the central area B, and LUT (C) may be associated with the area C on the right side. For example, when the number of LUT areas is fixed in this way, the LUT is allocated according to the image division pattern when only one column of an image is printed in the main scanning direction as shown in FIG. When using the central LUT (B) and printing in two rows, the left area A LUT (A), the right area C LUT (C), etc. may be used.

  Further, as a pattern of the LUT creation chart, for example, when there are three areas, patterns of four colors K, C, M, and Y may be created for each area, as shown in FIG. As shown in FIG. 11, two step patterns of K color and gray patterns of CMY three colors may be created for each area.

  In addition, regarding correction of the difference in aspect ratio between the images in the main scanning direction due to lens aberration, which is another problem, a pixel clock is set for each region divided in the main scanning direction according to the lens aberration characteristics. A method is conceivable.

For example, in the example shown in FIG. 29 described above, the image width of the central image area B is 89.1 mm, whereas the image widths of the left and right image areas A and C are 90.1 mm. There is a difference of 1 mm in width and + 1.11% in ratio. On the other hand, when the reference pixel clock frequency of the area B near the center of the angle of view is F _B , the frequency F _AC for exposing the areas A and C at both ends is F _AC = F _B / (1 + 0. 0111), the image width drawn in the area A and the area C can be printed with the same image width 89.1 mm as the area B.

That is, as shown in FIG. 12, the pixel clock frequency is set for each area, the frequency F _AC is set in the area A and the area C on both sides, and the frequency F _B is set in the center area B. Differences in aspect ratio can be suppressed.

  The setting of the pixel clock frequency for each region (area) is performed in the control unit 52. Based on the reference clock frequency generated from the clock signal generating means 56, the control unit 52 generates a pixel clock frequency for each region according to a lens characteristic (fθ characteristic) that is known in advance, and thereby optical writing is performed. The image recording device 30 is controlled to record an image.

  The switching position of the pixel clock frequency is the boundary position of the image, and the frequency selection of each area is determined by the image division pattern.

For example, as shown in FIG. 13, the pixel clock frequency may be optimized according to the position in the main scanning direction (the width of each region), and a number of frequencies corresponding to the number of divisions may be prepared and used. As shown in FIG. 13, when only one column is printed in the main scanning direction, one frequency F ₀ is sufficient. However, when two rows are printed, each main scanning is performed on each region. The frequencies F ₁ and F ₂ corresponding to the position in the direction are set. At this time, the two areas are not necessarily the same width, and differ depending on the size of each image, but one frequency is applied to the recording of one image.

Similarly, when printing in three rows, a total of three frequencies F _A2 , F _B2 , and F _C2 are set for each area, and when printing in four rows, four frequencies F _{A3 are set.} , F _B3 , F _C3 and F _D3 are set.

Alternatively, as shown in FIG. 14, the frequency may be fixed to three, and these three frequencies may be used in an appropriate combination according to the number of prints exposed in parallel in the main scanning direction. For example, as shown in FIG. 14, using frequency F _A, F _B, the F _C 3 Tsutoshi, in the case of one row printing, using a frequency F _B, in the case of two rows printing the frequency F _A And F _C may be used.

  In this way, by dividing the image exposure area and setting the frequency for each area and using it for image recording, it becomes possible to correct the distortion of the aspect ratio caused by the lens aberration, particularly at both ends of the exposure area. However, since the timing from the start point detection to the start of image writing must be constant, it must be returned to the reference frequency outside the image area.

  As described above, according to the present embodiment, a plurality of images (frames) can be arranged and exposed and processed in multiple rows in the main scanning direction, and the print processing capability can be improved and the apparatus can be used efficiently. Become. In addition, since the LUT is switched at each print position of the multi-row, and individually set and exposed, it is possible to suppress a difference in gradation and color depending on the position in the main scanning direction. Furthermore, since the pixel clock frequency is switched at each position in the multi-row and individually set for exposure, it is possible to suppress the difference in aspect ratio depending on the position in the main scanning direction.

  Next, the dustproof mechanism of the electrophotographic image forming apparatus according to the second embodiment of the present invention will be described in detail.

  FIG. 15 is a conceptual diagram schematically showing an electrophotographic image forming apparatus including a dustproof mechanism according to the second embodiment of the present invention. As shown in FIG. 15, the electrophotographic image forming apparatus of the present embodiment is basically substantially the same as the electrophotographic image forming apparatus of the first embodiment shown in FIG. Is different in that a dust-proof mechanism for preventing dust from adhering to the transparent member of the laser emission window of the optical writing device is provided with a cleaning unit for cleaning the transparent member.

  That is, the components other than the cleaning unit are the same as those in the first embodiment described above, and the same components are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted.

  As shown in FIG. 15, the electrophotographic image forming apparatus 100 of the present embodiment includes an image input / operation unit 110 and an image output unit 120, and the image input / operation unit 110 includes an image input unit 112, an operation unit. The image output unit 120 includes an optical writing unit 122, a printer output unit 124, a cleaning unit 126, and an output unit control unit 128.

  The cleaning unit 126 constitutes the dust-proof mechanism of the present invention, and cleans the transmissive member installed on the laser emission window of the optical writing device and removes adhering dust.

  The operation unit 114 gives various instructions to the image forming apparatus by the user. The user instructs the operation unit 114 about an image processing method and a finished print, and when the cleaning unit 126 performs a cleaning operation. An instruction of cleaning timing or the like to be performed is input. The output unit control unit 128 controls the cleaning operation of the cleaning unit 126 according to the cleaning timing specified by the operation unit 114.

  The electrophotographic image forming apparatus provided with the dustproof mechanism of the present invention is conceptually configured as described above. FIG. 16 shows a more specific apparatus configuration.

  FIG. 16 shows a more detailed configuration of an electrophotographic image forming apparatus provided with a dustproof mechanism according to the present embodiment. FIG. 16 mainly shows the apparatus configuration of the image output unit 120 and the dustproof mechanism of the electrophotographic image forming apparatus 100 conceptually shown in FIG.

  The electrophotographic image forming apparatus 10 shown in FIG. 16 is basically the same as the electrophotographic image forming apparatus 10 of the first embodiment shown in FIG. 2 described above, and the same components are denoted by the same reference numerals. A detailed description is omitted.

  The electrophotographic image forming apparatus 10 of this embodiment includes a dustproof mechanism 70 that cleans a laser emission window (described later) of the optical writing device 30.

  The dustproof mechanism 70 includes a cleaning unit 72 that cleans the laser emission window of the optical writing device 30, a driving unit 74 that drives the cleaning unit 72, a control unit 76 that controls the driving unit 74, and a cleaning timing that specifies the cleaning timing. A designation means 78 is included. Here, the cleaning unit 72 and the driving unit 74 correspond to the cleaning unit 126 described above, the output unit control unit 128 has the function of the control unit 76, and the operation unit 114 has the function of the cleaning timing designation unit 78. Also serves as.

  The image forming unit 12 is enlarged and shown in FIG. As described above, the image forming unit 12 is mainly configured by the optical writing device 30, the photosensitive drum 32, the developing device 34, and the intermediate transfer belt 36.

  In the electrophotographic image forming apparatus according to the first embodiment, the optical path of the laser beam emitted from the optical writing device 30 is turned back by the mirror 39 to form an image on the photosensitive drum 32. In the present embodiment, in order to simplify the apparatus configuration by omitting the mechanism for cleaning the mirror 39, the laser beam is directly irradiated onto the photosensitive drum 32 from the optical writing device 30 without arranging the mirror 39. I am doing so.

  The optical writing device 30 emits a laser beam modulated by an image signal, and scans the photosensitive drum 32 by a polygon mirror. A window glass 38 is attached to a laser emission window 37 that emits the laser beam, Prevents toner and paper dust from entering inside.

  FIG. 18 shows a view of the laser emission window 37 of the optical writing device 30 viewed from the emitted laser beam side. As shown in FIG. 18, the laser emission window 37 has a horizontally long and narrow rectangle, and a window glass 38 is fitted therein. The window glass 38 is attached by being closely fixed with a filler between the window glass 38 and the housing covering the entire optical writing device 30. Although the window glass 38 is used in the present embodiment, this is not particularly limited to glass, and may be a transparent plastic, or any material that transmits a laser beam, and may be a general transmissive member.

  The dustproof mechanism 70 of the present embodiment is for cleaning the surface of the window glass 38 and removing attached dust and the like. FIG. 19 shows an embodiment of the dustproof mechanism 70.

  The dustproof mechanism 70 shown in FIG. 19 is configured to wipe the surface of the window glass 38 with a soft material such as cloth. That is, the cleaning means 72 of the dust-proof mechanism 70 of this embodiment includes a wiping portion (contact portion) 72b that contacts the window glass 38 and wipes the surface of the window glass 38 at the tip of the support portion 72a. The drive means 74 is composed of a motor 74a and a wire 74b, and a support portion 72a of the cleaning means 72 is fixed to the wire 74b.

  When the wire 74b is driven by the motor 74a, the support portion 72a moves with the movement of the wire 74b, and the wiping portion 72b wipes the surface of the window glass 38.

  The driving of the motor 74a is controlled by the control means 76. The control means 76 is constituted by, for example, a microcomputer and has a predetermined control program built therein, and controls the driving of the motor 74a in accordance with an instruction input from the cleaning timing designation means 78 to control the cleaning operation of the window glass 38. It is supposed to be.

  The above-described operation unit 114 shown in FIG. 15 serves as the cleaning timing designating unit 78. Specifically, for example, a mouse or a keyboard connected to a microcomputer can be used.

  Further, as the dustproof mechanism 70, a liquid filling means 80 for filling the contact portion between the wiping portion 72b and the window glass 38 with a volatile liquid may be provided. This includes, for example, a tank 80a that stores volatile liquid such as ethanol and a nozzle 80b that fills the wiping portion 72b with liquid. The liquid filling operation can be controlled by the control means 76.

  The wiping portion 72b and the liquid filled in the wiping portion 72b are not particularly limited. However, since the window glass 38 is normally coated with anti-reflection coating, the coating is applied so that the window glass 38 is not peeled off. Those that do not affect are preferred. Moreover, it becomes easy to remove the dust adhering to the surface of the window glass 38 by filling the liquid.

  Further, the material and shape of the wiping portion 72b are not particularly limited. For example, in the case of a structure in which a soft thick cloth is wound around the square columnar support portion 72a, when one surface is slidably contacted with the window glass 38 and the wiping operation is performed several times, the surface becomes dirty. Other surfaces may be used. Furthermore, it is preferable that the wiping portion 72b itself can be replaced.

  The liquid filling unit 80 may be installed on one side of the laser emission window 37 and may be filled with liquid at the start of each wiping operation of the wiping unit 72b. The liquid filling unit 80 is the same as the wiping unit 72b. You may make it move along the window glass 38. At this time, the liquid filling unit 80 may move before the wiping unit 72b, and the wiping unit 72b may wipe the window glass 38 after spraying the liquid from the nozzle 80b onto the window glass 38.

  The wiping operation performed by the wiping unit 72b may be performed while moving once from one end to the other end. Moreover, you may comprise so that the wiping part 72b itself may wipe the window glass 38, rotating. If it does in this way, it will become easier to remove adhering dust.

  Next, a specific timing of wiping will be described as a dust-proof method that is an operation of the dust-proof mechanism 70 of the present embodiment. The timing for wiping is designated by the user via the cleaning timing designation means 78.

  As the wiping timing (cleaning timing), for example, when there is one print order, there is a case where it is automatically performed before the first image of the one print is exposed. According to this, when one print order is processed, the cleaning operation is always automatically performed at the beginning, and the laser beam always transmitted through the window glass 38 in a clean state is used. One exposure can be started.

  The processing sequence in this case will be described below along the flowchart of FIG.

  First, when a print instruction is issued by the user in step S200 of FIG. 20, image data to be printed is acquired in step S202. That is, the image data is read from the image input unit 112, and the image data is transferred to the output unit control unit 128 via the input unit control unit 116. Image data may be acquired by reading all image data to be printed at once, temporarily storing the image data in the internal memory of the apparatus, and taking out the image data from the image data for printing. The image data recorded on one image receiving paper P may be read.

  In step S204, the conveyance of the image receiving paper is started. That is, the image receiving paper P is pulled out from the roll paper 22, cut into a predetermined size sheet by the roll cutter 14, and conveyed. At this time, a cut sheet that has been cut to a predetermined size in advance can be pulled out from the sheet cassette 28 and used. Thereafter, the image receiving paper is continuously conveyed in parallel with the following processing such as exposure until printing is completed.

  In step S206, the controller 76 issues a wiping instruction to the driving unit 74 in order to perform cleaning once before starting printing for one item. Upon receiving the wiping instruction, the driving unit 74 drives the cleaning unit 72 to perform wiping (cleaning operation). That is, by driving the wire 74b by the motor 74a of the driving means 74, the cleaning means 72 fixed to the wire 74b is moved along the laser emission window 37, and the surface of the window glass 38 is removed by the wiping portion 72b of the cleaning means 72. Wipe off. At this time, it is desirable to fill the contact portion between the wiping portion 72 b and the window glass 38 with a volatile liquid such as ethanol from the nozzle 80 b of the liquid filling means 80.

  When the wiping operation is completed, in step S208, the optical writing device 30 exposes the photoconductor 32 to form an electrostatic latent image of the transferred image data on the photoconductor 32. Thereafter, in step S210, development and fixing are performed. That is, first, a toner image which is a visible image is formed by the developing device 34. Next, the toner image is transferred onto the image receiving paper P as a toner image, and the image receiving paper P on which the toner image is formed is fixed by the primary fixing means 16 and the secondary fixing means 18 and outputted as a finished print, and is sorted into the sorter 26. Is accumulated.

  Next, in step S212, it is determined whether or not one print creation process has been completed. If there is still image data to be printed, the process returns to step S208, and the next image is exposed. If one print creation process is completed, the process ends. The steps S202 to S206 may be executed in parallel.

  As the wiping timing, the optical writing device 30 may automatically clean the photosensitive drum 32 every time a predetermined number of images are exposed. The predetermined number of sheets may be input by the user from the cleaning timing designating unit 78, for example, 100 sheets, or may be selected by the user from several set values. When this cleaning timing is designated, the control means 76 counts the number of exposures of the optical writing device 30, and controls to perform the cleaning operation when the designated number of times is reached.

  Hereinafter, the processing sequence in this case will be described with reference to the flowchart of FIG.

  First, in step S300 of FIG. 21, the user issues a print instruction and designates a cleaning operation through the cleaning timing designating unit 78 for every N exposures. In step S302, image data to be printed is acquired. In step S304, the conveyance of the image receiving paper is started.

  Next, in step S <b> 306, the optical writing device 30 exposes an image on the photosensitive drum 32. Further, after the exposure of the image, the number of prints is counted in step S308. In this case, the number of exposed image receiving papers is counted. When the photosensitive drum 32 is rotated once, an image (one or more) is exposed on one image receiving paper. Alternatively, the rotational speed of the photosensitive drum 32 can be measured by a rotary encoder or the like. The control means 76 adds the number of prints to the cumulative number of prints after the previous cleaning (wiping).

  In step S <b> 310, the control unit 76 compares the cumulative number of prints after the previous wiping with a predetermined print number N. If the accumulated number of prints has not yet reached the predetermined number N, the wiping is not performed yet, and the process proceeds to the next step S316, where development and fixing are performed. When the cumulative number of prints reaches the predetermined number N, the window glass 38 of the laser emission window 37 is wiped in the next step S312.

  If wiping has been performed, in the next step S314, the control means 76 clears the cumulative number of prints to zero, and newly starts accumulating the cumulative number of prints. After wiping, development and fixing are performed in step S316.

  Thereafter, in step S318, it is determined whether or not the printing process has been completed for all image data to be printed. If image data to be printed still remains, the process returns to step S306, and the next image data is exposed. Further, when the print processing is completed for all the image data, the processing is ended.

  In the example described above, if it is determined that the cumulative number of printed sheets has reached a predetermined number N after exposure, the laser emission window 37 is wiped, and then development and fixing are performed. Actually, when the cumulative number of prints reaches the predetermined number N, the exposed image is developed and fixed, and at the same time, the wiping operation is performed before the next image is exposed. May be. Further, the comparison between the accumulated number of printed sheets and the predetermined number N (step S310), wiping (step S312), and clearing the accumulated number of printed sheets 0 (step S314) together with image data acquisition (step S302) and image receiving paper conveyance (step S304). Further, it may be performed in parallel before the exposure (step S306).

  Further, as a cleaning timing, cleaning may be performed when a predetermined time has elapsed since the previous cleaning operation. In this case, the control unit 76 counts the elapsed time and performs control so that the cleaning operation is performed every predetermined time.

  Hereinafter, the processing sequence in this case will be described with reference to the flowchart of FIG.

  First, in step S400 of FIG. 22, the user issues a print instruction and designates the cleaning operation through the cleaning timing designating unit 78 every predetermined time T. In step S402, image data to be printed is acquired. In step S404, the conveyance of the image receiving paper is started.

  Next, in step S <b> 406, the optical writing device 30 exposes an image on the photosensitive drum 32. In addition, after the image exposure, in step S408, the cumulative time since the previous cleaning operation (wiping) is counted. This accumulated time may be counted only when the system is on, or may be counted including the time when the system is off.

  In step S410, the control means 76 compares the accumulated time after the previous wiping with a predetermined time T. If the accumulated time has not yet reached the predetermined time T, the wiping is not performed yet, and the process proceeds to the next step S416 as it is and development / fixing is performed. When the accumulated time reaches the predetermined time T, the window glass 38 of the laser emission window 37 is wiped off in the next step S412.

  If wiping has been performed, in the next step S414, the control means 76 clears the accumulated time to 0 and starts counting the accumulated time anew. After wiping, development / fixing is performed in step S416.

  Thereafter, in step S418, it is determined whether or not the printing process has been completed for all image data to be printed. If image data to be printed still remains, the process returns to step S406, and the next image data is exposed. Further, when the print processing is completed for all the image data, the processing is ended.

  Even in the example described above, when the accumulated time reaches a predetermined time T after exposure, the laser emission window 37 is wiped, and then development and fixing are performed. When the accumulated time reaches the predetermined time T, the exposed image may be developed and fixed, and in parallel, a wiping operation may be performed before the next image is exposed. Further, the comparison between the accumulated time and the predetermined time T (step S410), wiping (step S412), and clearing the accumulated time 0 (step S414) are performed together with image data acquisition (step S402) and image receiving paper conveyance (step S404). You may make it perform in parallel before (step S406).

  Moreover, you may make it perform cleaning as the cleaning timing at the arbitrary time designated by the user. According to this, when the user finds an image defect such as a vertical stripe by looking at the output print, for example, cleaning can be performed immediately. This image defect may be determined by the user looking at the print, or the print may be scanned by a CCD sensor or the like to automatically detect the presence or absence of vertical stripes. Alternatively, it may be detected from the surface of the photosensitive drum 32 after exposure instead of printing, and further, the laser beam itself emitted from the optical writing device 30 is received at the same position as the photosensitive drum 32. Further, laser beam impermeability, light quantity shortage, and the like may be detected.

  When the image defect is automatically detected, the control unit 76 may control to automatically start the cleaning operation as it is. In this way, the cleaning operation can be completely automated.

  In the above example, the driving means 74 of the cleaning means 72 is the motor 74a and the wire 74b driven by the motor 74a. However, the driving means 74 is not limited to this, and the cleaning means 72 is attached to the window glass 38. Anything can be used as long as it can be moved in parallel. For example, a ball screw may be used instead of a wire.

  As described above, according to the present embodiment, the user only specifies the cleaning timing, and thereafter, the cleaning operation is automatically performed at the specified timing. You can create a print without And by always cleaning automatically, dust attached to the window glass of the laser emission window can always be removed and kept clean anytime, preventing the occurrence of image defects such as vertical stripes, It is possible to maintain high image quality.

  As described above, the image forming apparatus may be designed so that the user can freely specify the cleaning timing from among a plurality of cleaning timings, or all the cleaning timings described above can be specified. Instead, only some cleaning timings may be designated. Alternatively, for example, one cleaning timing for performing a cleaning operation for each predetermined number of exposure sheets may be set in advance, and the user may only specify the number of sheets. Thus, by limiting the functions, the apparatus configuration and the apparatus cost may be reduced, and the user may select an apparatus according to the purpose.

  Next, a third embodiment of the present invention will be described.

  FIG. 23 is a conceptual diagram schematically showing an electrophotographic image forming apparatus including a dustproof mechanism according to the third embodiment of the present invention. As shown in FIG. 23, the electrophotographic image forming apparatus of this embodiment is basically substantially the same as the electrophotographic image forming apparatus of the first embodiment shown in FIG. The photographic image forming apparatus is different from the electrophotographic image forming apparatus of the first embodiment as a dust-proof mechanism for preventing dust from adhering to the transparent member of the laser emission window of the optical writing apparatus. The difference is that a dustproof portion is provided that covers the periphery, seals and pressurizes the inside thereof to prevent dust from adhering to the laser emission window.

  That is, the components other than the dustproof portion are the same as those in the first embodiment described above, and the same components are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted.

  As shown in FIG. 23, the electrophotographic image forming apparatus 100 of this embodiment includes an image input / operation unit 110 and an image output unit 120. The image input / operation unit 110 includes an image input unit 112, an operation unit, and the like. The image output unit 120 includes an optical writing unit 122, a printer output unit 124, a dustproof unit 127, and an output unit control unit 128.

  The dustproof portion 127 constitutes the dustproof mechanism of the present invention, and prevents dust from adhering to the transparent member installed in the laser emission window of the optical writing device. The operation of the dustproof unit 127 is controlled by the output unit control unit 128.

  The electrophotographic image forming apparatus provided with the dustproof mechanism of the present embodiment is conceptually configured as described above. FIG. 24 shows a more specific apparatus configuration.

  FIG. 24 shows the apparatus configuration of the image output unit 120 and the dustproof mechanism of the electrophotographic image forming apparatus 100 conceptually shown in FIG.

  The electrophotographic image forming apparatus 10 shown in FIG. 24 is basically the same as the electrophotographic image forming apparatus 10 of the first embodiment shown in FIG. 2 described above, and the same components are denoted by the same reference numerals. A detailed description is omitted.

  The electrophotographic image forming apparatus 10 of the present embodiment includes a dustproof mechanism 90 that prevents dust from adhering to a transparent member (described later) of a laser emission window of the optical writing device 30. The dust-proof mechanism 90 of this embodiment prevents dust from adhering to the transparent member of the laser emission window by sealing the periphery of the laser emission window of the optical writing device 30 and pressurizing the inside thereof. Corresponds to the dustproof part 127.

  The image forming unit 12 is the same as that of the second embodiment shown in FIG. 17, and mainly includes an optical writing device 30, a photosensitive drum 32, a developing device 34, and an intermediate transfer belt 36. The optical writing device 30 emits a laser beam modulated by an image signal, and scans the photosensitive drum 32 by a polygon mirror. A window glass 38 is attached to a laser emission window 37 that emits the laser beam, Prevents toner and paper dust from entering inside. Further, the view of the laser writing window 37 of the optical writing device 30 viewed from the side of the emitted laser beam is the same as FIG. 18 in the second embodiment described above. As shown in FIG. 18, the laser emission window 37 has a long and narrow rectangular shape, and a window glass 38 is fitted therein. The window glass 38 is attached by being closely fixed with a filler between the window glass 38 and the housing covering the entire optical writing device 30. Although the window glass 38 is used in the present embodiment, this is not particularly limited to glass, and may be a transparent plastic, or any material that transmits a laser beam, and may be a general transmissive member.

  The dustproof mechanism 90 of this embodiment is for preventing dust from adhering to the surface of the window glass 38. FIG. 25 shows an embodiment of the dustproof mechanism 90.

  The dustproof mechanism 90 shown in FIG. 25 prevents dust from adhering to the transparent member of the laser emission window by sealing the periphery of the laser emission window 37 of the optical writing device 30 and pressurizing the inside thereof. .

  As shown in FIG. 25, the dustproof mechanism 90 mainly covers the laser emission window 37 of the optical writing device 30 and the housing of the optical writing device 30, and particularly seals the portion around the laser emission window 37. A duct 91 formed, an openable / closable shutter part 93 formed in an opening 92 at one end of the duct 91 so as to allow a laser beam to pass through, and the duct 91 to pressurize the inside of the duct 91. It is constituted by a fan 94 installed at the other end of the duct 91 for feeding air.

  The air suction port of the fan 94 faces the side opposite to the side from which the laser beam is emitted from the optical writing device 30, and a dustproof filter 95 is provided inside the fan 94 (duct 91 side). 94 removes dust and the like in the air taken into the duct 91 to clean the air taken into the duct 91. The dustproof filter 95 has a double structure of an outer first filter 95a and an inner second filter 95b, and the outer first filter 95a has a dust collection rate higher than that of the inner second filter 95b. Is expensive and replaceable. As described above, since the dustproof filter 95 has a double structure, it is possible to prevent dust from entering the duct 91 when the outer first filter 95a is replaced.

  An openable / closable lid (shutter) 96 is installed in front of the air suction port on the front side of the fan 94 so that the fan 94 is closed when outside air is not taken in. The shutter section 93 is opened at the time of optical writing (exposure) and emits a laser beam emitted from the optical writing apparatus 30 outward from the opening 92. There are no particular limitations on the opening / closing mechanisms of the lid 96 and the shutter section 93, and any opening / closing mechanism may be employed. For example, the shutter 93 may be opened by using one end as a hinge and the other end pulled upward by a solenoid.

  At the time of optical writing (exposure), the lid 96 opens, the fan 94 rotates, the outside air is taken into the duct 91 and the inside of the duct 91 is pressurized, and the shutter portion 93 is opened. Is opened, and exposure with a laser beam is performed. At this time, the air taken into the duct 91 by the fan 94 flows as shown by arrows in the figure, and is exhausted to the outside from the opening 92.

  As described above, the air suction port of the fan 94 that takes air into the duct 91 is disposed on the side opposite to the side from which the laser beam is emitted, and the toner scattered when forming the toner image on the photosensitive drum 32, It is designed not to be affected by paper scraps scattered from the image receiving paper. Further, it is preferable to provide a partition wall 97 so as to block the source of such dust and the air intake port of the fan 94 so that the dust does not easily move to the air intake port side of the fan 94. The partition 97 is provided with a slit 98 for allowing the laser beam to pass therethrough.

  Next, the operation of the dustproof mechanism of this embodiment will be described.

  When a print instruction is issued by the user, the image data is read and transferred, and the image receiving paper P is pulled out from the roll paper 22, and is cut into a sheet of a predetermined size by the roll cutter 14 and conveyed. .

  At the same time, the lid 96 is opened and the fan 94 is rotated, whereby clean air that has passed through the dust filter 95 is sucked into the duct 91 and the inside of the duct 91 is pressurized. After pressurizing the inside of the duct 91, the shutter part 93 is opened and the opening part 92 is opened. Thereby, an air flow as indicated by an arrow is generated in the duct 91 of FIG. That is, the air sucked from the fan 94 flows through the duct 91 and is discharged from the opening 92.

  At this time, since the inside of the duct 91 is pressurized, dirty air containing dust does not flow into the duct 91 from the opening 92. Further, since the dust-proof mechanism 90 and the portion where the electrostatic latent image, the toner image, and the like are formed are partitioned by the partition wall 97, dirty air containing dust near the toner image forming portion moves to the dust-proof mechanism side. Therefore, dust in the air sucked from the fan 94 can be further reduced. By such a function of the dustproof mechanism 90, it is possible to sufficiently prevent dust and the like from adhering to the window glass 38.

  Under such circumstances, optical writing is performed by the optical writing device 30. That is, the optical writing device 30 exposes the photosensitive drum 32 to form an electrostatic latent image of the transferred image data on the photosensitive drum 32. When the exposure is completed, the shutter portion 93 is closed, the rotation of the fan 94 is stopped, and the lid 96 on the front surface of the fan 94 is closed.

  On the photosensitive drum 32 on which the electrostatic latent image is formed, a toner image which is a visible image is formed by the developing device 34. The toner image is transferred onto the image receiving paper P as a toner image, and the image receiving paper P on which the toner image is formed is fixed by the primary fixing means 16 and the secondary fixing means 18 and output as a finished print, and is sorted by the sorter 26. Accumulated.

  Thus, according to this embodiment, when optical writing (exposure) is not performed, the periphery of the laser emission window 37 of the optical writing device 30 is sealed with the duct 91, and a laser beam is emitted during exposure. Therefore, only the minimum necessary opening portion is opened, and air is sucked into the duct 91 by the fan 94 to pressurize the inside of the duct 91 so that dirty air containing dust or the like does not flow from the opening portion. By doing so, adhesion of dust to the window glass 38 of the laser emission window 37 can be prevented.

  The electrophotographic image forming apparatus and the dustproof mechanism thereof according to the present invention have been described in detail above. However, the present invention is not limited to the above examples, and various improvements and modifications can be made without departing from the gist of the present invention. Of course, you may also do.

1 is a conceptual diagram schematically showing an electrophotographic image forming apparatus according to a first embodiment of the present invention. 1 is a configuration diagram showing the electrophotographic image forming apparatus of the present embodiment in more detail. It is explanatory drawing which shows a mode that multi-row printing is performed in the main scanning direction. It is explanatory drawing which shows the method of producing LUT for density correction. It is a flowchart which shows the method of producing LUT. It is explanatory drawing which shows the method using LUT. It is explanatory drawing which shows the division | segmentation method of LUT. It is explanatory drawing which shows LUT at the time of fixing a division area. It is explanatory drawing which shows a mode that LUT is applied according to multi-row printing. It is explanatory drawing which shows the example of the pattern of the chart for LUT creation. It is explanatory drawing which shows the other example of the pattern of the chart for LUT creation. It is a diagram which shows the frequency set corresponding to the area. It is explanatory drawing which shows a response | compatibility with the exposure area and frequency in the case of multi-row printing. It is another explanatory drawing which shows a response | compatibility with the exposure area and frequency in the case of multi-row printing. It is a conceptual diagram which shows typically the electrophotographic image forming apparatus provided with the dustproof mechanism which concerns on 2nd Embodiment of this invention. 1 is a schematic configuration diagram of an electrophotographic image forming apparatus including a dustproof mechanism according to the present embodiment, which mainly represents specific device configurations of an image output unit and a dustproof mechanism. 1 is an enlarged schematic configuration diagram illustrating an image forming unit of an electrophotographic image forming apparatus according to an exemplary embodiment. It is the front view which looked at the laser emission window of the optical writing device from the direction which a laser beam advances. It is a schematic block diagram which shows the dustproof mechanism which concerns on this embodiment. In this embodiment, it is a flowchart which shows the sequence of the dust-proof method which performs cleaning operation | movement at the beginning of one case. In this embodiment, it is a flowchart which shows the sequence of the dust prevention method which performs cleaning operation | movement every time a predetermined number of sheets are printed. In this embodiment, it is a flowchart which shows the sequence of the dust prevention method which performs cleaning operation | movement for every predetermined time. It is a conceptual diagram which shows typically the electrophotographic image forming apparatus provided with the dustproof mechanism which concerns on 3rd Embodiment of this invention. 1 is a schematic configuration diagram of an electrophotographic image forming apparatus including a dustproof mechanism according to the present embodiment, which mainly represents specific device configurations of an image output unit and a dustproof mechanism. It is a schematic block diagram which shows the dustproof mechanism which concerns on this embodiment. It is a block diagram which shows the outline of an optical writing device. It is explanatory drawing which shows the problem by the lens aberration in an optical writing apparatus. It is a diagram which shows the f (theta) property of a lens. It is explanatory drawing which shows the difference in the aspect ratio by the exposure position by lens aberration.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electrophotographic image forming apparatus, 12 ... Image forming part, 14 ... Roll cutter, 16 ... Heating and pressing roller (primary fixing means), 18 ... Belt fixing apparatus (secondary fixing means), 20 ... XY cutter, 22 ... roll paper, 24 ... print head, 26 ... sorter, 28 ... sheet cassette, 30 ... optical writing device, 32 ... photoconductor drum, 34 ... developing device, 36 ... intermediate transfer belt, 37 ... laser emission window, 38 ... Window glass, 39 ... Mirror, 40 ... Charger, 42 ... Primary transfer roller, 44 ... Secondary transfer roller, 46 ... Cleaning device, 50 ... Densitometer, 52 ... Controller, 54 ... Memory for LUT, 56 ... Clock signal Generating means, 60 ... image receiving paper, 62 ... test chart, 63 ... LUT, 70 ... dust-proof mechanism, 72 ... cleaning means, 72a ... support part, 72b ... wiping part, 74 ... drive means, 7 a ... motor, 74b ... wire, 76 ... control means, 78 ... cleaning timing designation means, 80 ... liquid filling means, 80a ... liquid tank, 80b ... nozzle, 90 ... dustproof mechanism, 91 ... duct, 62 ... opening, 93 ... Shutter unit, 94 ... Fan, 95 ... Dust-proof filter, 95a ... First filter, 95b ... Second filter, 96 ... Lid, 97 ... Partition, 98 ... Slit, 100 ... Electrophotographic image forming apparatus, 110 ... Image input / Operation unit 112 ... Image input unit 114 ... Operation unit 116 ... Input unit control unit 118 ... Monitor 120 ... Image output unit 122 ... Optical writing unit 124 ... Printer output unit 128 ... Output unit control Part, 130 ... sorter

Claims (28)

An electrophotographic image forming apparatus that exposes a photoreceptor to form an electrostatic latent image, develops and visualizes the image, and transfers the image onto an image receiving paper to form an image,
When the exposure area on the photoconductor is divided into a plurality of areas arranged in the main scanning direction substantially orthogonal to the moving direction of the photoconductor, and at least two or more of the areas are exposed with an image,
An electrophotographic image forming apparatus comprising: exposure condition setting means for setting an exposure condition in an area where the image is exposed in accordance with a position of the area in the main scanning direction.   The exposure condition setting unit corrects the density unevenness due to the position in the main scanning direction by optimizing the LUT for setting the density for exposing the area according to the position in the main scanning direction of the area where the image is exposed. The electrophotographic image forming apparatus according to claim 1.   The electrophotographic image forming apparatus according to claim 2, wherein the LUT is created by outputting a LUT creation chart and measuring the density.   4. The electrophotographic image forming apparatus according to claim 2, wherein the creation of the LUT is automatically performed at the head of the print processing for each print order.   4. The electrophotographic image forming apparatus according to claim 2, wherein the LUT can be created at an arbitrary time.   The exposure condition setting means sets a pixel clock frequency for exposing an image in an area where the image is exposed to an image area in the main scanning direction corresponding to a lens aberration characteristic of an exposure optical system for exposing the photoconductor. The electrophotographic image forming apparatus according to claim 1, wherein the difference in the aspect ratio of the image in the main scanning direction due to the lens aberration is corrected by setting according to the position.   The exposure condition setting means optimizes a LUT for setting a density for exposing the area in accordance with a position in the main scanning direction of the area where the image is exposed, and images in the area where the image is exposed. 2. The pixel clock frequency to be exposed is set in accordance with the position of each image area in the main scanning direction corresponding to the lens aberration characteristic of an exposure optical system for exposing the photosensitive member. The electrophotographic image forming apparatus described in 1. A dust-proof mechanism for cleaning a transparent member attached to a laser emission window provided on the front surface of an optical writing device of an electrophotographic image forming apparatus,
Cleaning means for cleaning the surface of the permeable member;
Drive means for driving the cleaning means to perform a cleaning operation on the permeable member;
Control means for controlling the drive means;
And a dustproof mechanism for an electrophotographic image forming apparatus, wherein the permeable member is automatically cleaned.   The said cleaning means is cleaned by wiping off the surface of the said permeable member, contacting the said permeable member, and moving along the said permeable member by the said drive means. Dust-proof mechanism of the electrophotographic image forming apparatus.   The dust-proof mechanism of the electrophotographic image forming apparatus according to claim 9, wherein the driving unit moves the cleaning unit along the transparent member by a wire and motor operation.   11. The dust-proof mechanism of the electrophotographic image forming apparatus according to claim 9, further comprising a liquid filling unit that fills a volatile liquid in a portion where the cleaning unit contacts the transparent member. A dust-proof mechanism for an electrophotographic image forming apparatus.   The dust-proof mechanism of an electrophotographic image forming apparatus according to any one of claims 9 to 11, wherein a portion of the cleaning unit that contacts the transparent member is replaceable.   The control unit controls the driving unit so that the cleaning unit performs a cleaning operation on the transparent member before the optical writing apparatus exposes the first image for one print order. The dust-proof mechanism of the electrophotographic image forming apparatus according to any one of claims 8 to 12.   The control unit controls the driving unit so that the cleaning unit performs a cleaning operation on the transmissive member every time the optical writing device exposes a predetermined number of images. The dust-proof mechanism of the electrophotographic image forming apparatus according to any one of -12.   13. The control unit according to claim 8, wherein the control unit controls the driving unit so that the cleaning unit performs a cleaning operation on the permeable member every time a predetermined time elapses. Dust-proof mechanism of the electrophotographic image forming apparatus.   The said control means controls a drive means so that the said cleaning means may perform the cleaning operation | movement with respect to the said permeable member at the designated arbitrary timings, The any one of Claims 8-12 characterized by the above-mentioned. Dust-proof mechanism of the electrophotographic image forming apparatus. 13. The dust-proof mechanism of the electrophotographic image forming apparatus according to claim 8, further comprising: a cleaning timing designating unit that designates a cleaning timing at which the cleaning unit performs a cleaning operation on the transmissive member. With
The cleaning timing designating unit, as the cleaning timing, before the optical writing device exposes a first image for one print order, every time the optical writing device exposes a predetermined number of images, and every elapse of a predetermined time. , And any time point can be designated. A dustproof mechanism for an electrophotographic image forming apparatus. A dust-proof method for cleaning a transparent member attached to a laser emission window provided in front of an optical writing device of an electrophotographic image forming apparatus,
An electrophotographic image formation characterized in that, when a print instruction is given, the transparent member is automatically cleaned prior to the exposure of the first image for each print order. Dust proofing method for equipment. A dust-proof method for cleaning a transparent member attached to a laser emission window provided in front of an optical writing device of an electrophotographic image forming apparatus,
When there is a print instruction, count the number of exposed prints,
An electrophotographic image forming apparatus, wherein the transmissive member is automatically cleaned when the cumulative number of printed sheets after the previous cleaning of the transmissive member reaches a predetermined number of sheets given in advance. Dust-proof method. A dust-proof method for cleaning a transparent member attached to a laser emission window provided in front of an optical writing device of an electrophotographic image forming apparatus,
When there is a print instruction, the permeable member is automatically cleaned when the accumulated time after the previous cleaning of the permeable member reaches a predetermined time given in advance. A dustproof method for an electrophotographic image forming apparatus.   21. The cleaning of the permeable member is performed by wiping off the surface of the permeable member while bringing a cleaning means into contact with and moving the surface of the permeable member. 2. A dustproof method for an electrophotographic image forming apparatus according to 1. A dust-proof mechanism for preventing dust from adhering to a transparent member attached to a laser emission window provided on the front surface of an optical writing device of an electrophotographic image forming apparatus,
A duct having an opening for covering a casing around a laser emission window of the optical writing device so as to be sealed and allowing a laser beam emitted from the laser emission window to pass through;
An openable and closable shutter attached to the opening of the duct;
A fan for sending air into the duct;
A dust filter for removing dust in the air sent into the duct by the fan;
The clean air is sent to the inside of the duct by the fan through the dust filter, the inside of the duct is pressurized, and the pressurized air is exhausted by opening the shutter portion. A dustproof mechanism for an electrophotographic image forming apparatus, characterized in that it prevents dust from adhering to a conductive member.   23. The dustproof mechanism of an electrophotographic image forming apparatus according to claim 22, wherein the shutter portion opens and closes only when the optical writing device performs an optical writing operation.   24. The electronic device according to claim 22, wherein when the optical writing device performs an optical writing operation, the shutter is opened after the fan is actuated to pressurize the duct. A dust-proof mechanism for photographic image forming devices.   The dustproof filter has a double structure, and the outer dustproof filter has a higher dust collection rate than the inner dustproof filter and is replaceable. 2. A dustproof mechanism for an electrophotographic image forming apparatus according to item 1.   26. The air intake port of a fan for sending air into the duct is directed to a side opposite to a side from which a laser beam is emitted from the optical writing device. 2. A dustproof mechanism for an electrophotographic image forming apparatus according to item 1.   27. The dust-proof mechanism of the electrophotographic image forming apparatus according to claim 26, wherein a dust is blocked between the air suction port side and a side from which the laser beam is emitted so that the dust does not easily move. . 28. The dust-proof mechanism of an electrophotographic image forming apparatus according to claim 26, wherein a lid that can be opened and closed is installed on a front surface of the air suction port.

Images