JP2006267665A - Scanning type exposure device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning type exposure device which has capability to effectively detect minor contamination and scratches or the like on an image carrying body and can realistically be assembled into an image forming device. <P>SOLUTION: The scanning type exposure device, which includes a light source and an optical scanner that scans the body to be exposed located within a prescribed range by the light beams from the light source, is provided with a beam splitter arranged between the light source and the optical scanner, a condensing lens which converges scattered light beams being taken by the beam splitter from the body to be exposed and a photodetector which detects the scattered light beams being converged by the condensing lens. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a scanning exposure apparatus capable of detecting a scattering state of scanning light, and an image forming apparatus that has the exposure apparatus and detects certain types of defects related to an image at an early stage and can prevent defects. Relates to the device.

  A photosensitive member is used as an image carrier, and an electrostatic latent image is formed by performing desired image exposure on the photosensitive member, and a colored toner is attached to the electrostatic latent image on the image carrier in a development process to form a toner image. An image forming apparatus that obtains a final output through a process of visualizing and transferring the toner image onto a transfer material as an output medium is widely used as a copying machine, a printer, a fax machine, and the like.

  There are various types of exposure apparatuses that perform image exposure with the image forming apparatus described above. Light from a light source that is intensity-modulated in accordance with electronic information of the image is distributed to a desired range using an optical scanning device, and linear or A scanning exposure apparatus that realizes image exposure for a planar scanning range is one of the most widely used exposure apparatuses.

  In an image forming apparatus using an image carrier, an image defect occurs due to abnormalities on the surface of the image carrier such as dirt or scratches. In a conventional image forming apparatus, a mechanism for detecting an abnormality on the surface of an image carrier is not general, and since an abnormality cannot be detected until an image defect actually occurs, it has been one of the major causes of defects.

  As a technique that can provide an answer to this problem, a line-type light receiving element is arranged in the vicinity of the image carrier, and the line type light-receiving element is read out in synchronization with the scanning position of the optical scanning device, and reflected on the image carrier. A method has been proposed in which the detected light is detected and the unevenness on the surface of the image carrier is determined from the intensity (see Patent Document 1).

Japanese Patent Laid-Open No. 2002-168611

  However, in the configuration described in Patent Document 1, since reflected light is detected, the sensitivity to very slight contamination and scratches on the surface of the image carrier is low, and if it is applied to an image forming apparatus, the image carrier is used. A space for arranging the line type light receiving elements over the entire scanning width is required in the vicinity of the body, and it is extremely difficult to apply to a recent downsized image forming apparatus.

  The present invention provides a scanning exposure apparatus that has the ability to effectively detect minor contamination and scratches on an image carrier and can be practically incorporated into an image forming apparatus, and an image carrier by incorporating this. An object of the present invention is to provide an image forming apparatus that can detect and deal with dirt and scratches on a body surface before image defects become apparent.

  In order to achieve the above object, a light source and an optical scanning device are provided as a scanning exposure apparatus including a light source and an optical scanning device that scans an object to be exposed within a predetermined range with light from the light source. A beam splitter disposed between the beam splitter, a condensing lens for condensing scattered light from the exposed object taken out by the beam splitter, and light detection for detecting the scattered light collected by the condensing lens And a container.

According to the second aspect of the present invention, a photosensitive member is used as the image carrier, and an electrostatic latent image is formed by performing desired image exposure on the photosensitive member, and the electrostatic latent image on the image carrier is colored in the development process. As an image forming apparatus having a process of transferring a toner image to a transfer material by attaching toner to a toner image, as a means for performing image exposure, a light source and light from the light source are within a predetermined range. A scanning exposure apparatus including an optical scanning device that scans the surface of the photosensitive member. The scanning exposure device includes a beam splitter provided between the light source and the optical scanning device, and a surface of the photosensitive member taken out by the beam splitter. A condenser lens that collects the scattered light, and a photodetector that detects the scattered light collected by the condenser lens,
A recording apparatus that records information related to light scattering of the photosensitive member based on the detection signal of the photodetector and the operation information of the image forming apparatus, and changes in the operation of the image forming apparatus based on the information of the recording apparatus, to the outside of the image forming apparatus And a control device that performs the warning.

  According to a third aspect of the present invention, in the second aspect of the present invention, the recording apparatus uses the detection signal of the photodetector and the operation information of the image forming apparatus to obtain information on light scattering on the surface of the photoconductor and / or the operation. A history recording apparatus that stores time series in association with a history, wherein the control device changes the operation of the main body and warns the outside of the image forming apparatus based on information of the history recording apparatus.

  According to the first aspect of the present invention, the light from the light source is swung by the optical scanning device in the same way as a normal scanning exposure device, and scans the object to be exposed disposed at a predetermined position. The light that has reached the object to be exposed is reflected and scattered according to the surface state of the object to be exposed at the arrival point. Here, it is assumed that the incident direction of the scanning light is set so that the regular reflection light from the exposure object does not return to the scanning exposure apparatus.

  Then, when the light is incident on a normal surface of the object to be exposed, that is, a surface that is smooth and highly specularly reflected, very little light returns to the scanning exposure apparatus. However, on an abnormal surface with uneven contaminants and scratches on the surface, scattering due to the contaminants and scratches occurs, and part of the scattered light traces back on the incident path from the scanning exposure apparatus and goes back to the light source. . Furthermore, a part is bent from the optical path to the light source by a beam splitter disposed between the optical scanning device and the light source, and reaches the photodetector via the condenser lens.

  From the above, it can be seen that the intensity of light reaching the photodetector on the normal surface and the abnormal surface changes at a large ratio, and the detection of the abnormality conforms to the spatial resolution of the scanning optical system. In addition, by setting the light source and the light detector to be in an optically conjugate condition and using a confocal optical system, scattered light from the exposure position reaching the light detector and multiple scattering from outside the exposure position The ratio of light and ambient light can be maximized, which is very advantageous in terms of detection sensitivity and effective spatial resolution.

  In the above configuration, it is not necessary to provide a photodetector or the like in the vicinity of the object to be exposed, and it is sufficient that only the optical path can be secured around the object to be exposed as in the conventional scanning exposure apparatus. That is, it is possible to realize a scanning type exposure apparatus that can detect minor scratches and contamination with high sensitivity and high spatial resolution without changing the configuration in the vicinity of the object to be exposed.

  According to the second aspect of the present invention, a photosensitive member is used as the image carrier, and an electrostatic latent image is formed by performing desired image exposure on the photosensitive member, and the electrostatic latent image on the image carrier is developed in the development process. A scanning type exposure according to claim 1 as an image exposure means of an image forming apparatus for obtaining a final output through a process of attaching a colored toner to a toner to visualize the toner image and transferring the toner image onto a transfer material as an output medium. Use the device. Therefore, the image forming apparatus according to the second aspect detects light at a very early stage when the surface of the photoconductor is damaged or the toner adheres and is contaminated while repeating the image forming operation. The incident light quantity of the device changes and can be detected. Further, it is not necessary to arrange a mechanism for detecting scattered light in the vicinity of the photosensitive member, and this does not hinder downsizing of the apparatus.

  Furthermore, the image forming apparatus according to the present invention has a recording device that records information related to light scattering on the surface of the photoreceptor based on the detection signal of the light detector and the operation information of the image forming device, and the control device outputs the light detector. Can be properly interpreted in consideration of the operation of the main body. For example, an area that does not require improper recording or inspection by enabling recording only during a period in which scanning light exposes an evaluation area on the surface of the photoreceptor under appropriate exposure conditions, or by evaluating only recording during the period. This information can be evaluated by removing the scattering information of the light source, and shading correction is performed on the output signal of the light detector by recording the light output information together with the light detector output signal and the optical system scanning position information. It becomes possible to improve the evaluation accuracy. Alternatively, by recording the output signal of the photodetector and the scanning position information on the photosensitive member together, the control device can analyze the abnormal part on the photosensitive member and its state from the information on the light scattering and its distribution. It becomes possible, and the prediction accuracy of the deterioration of the abnormality can be increased.

  With the above configuration, the control device can detect an abnormality on the surface of the photoconductor before it becomes apparent as a defect, and based on this, the operation of the main body can be changed, for example, the adjustment operation or the setting change, or the image signal can be corrected. It is possible to prevent the occurrence of defects by suppressing the deterioration of abnormalities and the influence on the image, and by giving warnings about the presence of the abnormality outside the image forming apparatus, its cause, countermeasures, and the timing of the defect appearance. it can.

  That is, with the configuration based on the present claims, it is possible to realize an image forming apparatus that can prevent a malfunction due to an abnormality of the surface of the photosensitive member in advance and can notify a countermeasure item in advance in a small and low cost.

  According to the invention of claim 3, by recording information on light scattering along with time, operation history, etc. in time series, the control device is caused by considering the transition in addition to the position and distribution of light scattering intensity. The situation can be determined, and a more accurate failure can be predicted, so that the operation of the main body can be changed more accurately and a warning can be given to the outside of the image forming apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
A scanning exposure apparatus according to the present invention is shown in FIG.

  The laser diode 111 is driven by a laser driver (not shown) in accordance with a video signal from a control device (not shown). The laser light from the laser diode 111 is converged by the collimator lens 112, passes through the beam splitter, is reflected by the polygon mirror 141 that is driven to rotate at a constant speed by the motor, and changes on the optical path 101 that changes depending on the rotation angle of the polygon mirror 141. Then, the light passes through the f-θ lens 142 and enters the exposure object 151 placed at a predetermined position.

  The optical path 101 changes as the polygon mirror 141 rotates, and the f-θ lens 142 moves the incident position at a constant speed on a predetermined straight line on the surface of the object 151 to be exposed. A part is absorbed, and the rest is emitted as specularly reflected light 102a and irregularly reflected light 102b. A part of the irregularly reflected light 102 b traces on the optical path 101 in the opposite direction to the incident time, passes through the f-θ lens 142, is reflected by the polygon mirror 141, and reaches the beam splitter 131. Then, the light reflected by the beam splitter 131 is converged by the condenser lens 122 and detected by the optical sensor 121 including the aperture 121a and the photodiode 121b at the confocal position with the laser diode 111.

  By moving the object to be exposed on a predetermined path, scanning exposure can be performed in a two-dimensional region, and at the same time, an output signal of the optical sensor 121 reflecting a change in scattered light can be obtained. Since the ratio of the regular reflection light 102a and the irregular reflection light 102b varies greatly depending on the surface state of the object to be exposed, the amount of light detected by the optical sensor 121 varies greatly depending on the surface state of the object to be exposed. That is, by monitoring the output of the optical sensor, it is possible to know the change in the surface state at the scanning position of the object to be exposed.

  That is, by using the operation type exposure apparatus shown in the present embodiment, the output signal of the optical sensor 121 is read by a control device (not shown), so that the surface state of the object to be exposed is extremely sensitive and almost the same as that of the scanning exposure apparatus. We can know with spatial resolution.

<Embodiment 2>
A portion related to the present invention of the image forming apparatus according to the present invention is shown in FIG.

  The scanning exposure apparatus 200 shown in the first embodiment as an exposure apparatus that performs image exposure is installed so that the scanning light is focused on the photoreceptor 210 via the reflecting mirror 214. Here, the scanning light is set so as not to be perpendicularly incident on the surface of the photosensitive member 210 at an arbitrary scanning position.

  Around the photoreceptor 210, a charging roller 211, a developing device 212, a transfer device (not shown), and a cleaning device 213 are disposed, and the scanning exposure device 200 also constitutes an image forming mechanism. The image forming mechanism functions as follows.

  That is, the photosensitive member is driven to rotate by the photosensitive member driving motor 215, charged to a predetermined surface potential in the vicinity of the contact portion with the charging roller 211, and image-exposed by the scanning light of the scanning exposure apparatus 200 to form an electrostatic latent image. Then, a toner image is formed with colored toner in the developing device 212. This toner image is transferred onto a transfer material by a transfer device (not shown) to obtain a desired image. The surface of the photosensitive member 210 after the toner image is transferred reaches the cleaning device 213 and is cleaned, and again proceeds to the contact portion with the charging roller 211 to perform the next image formation.

  The drive mechanism of the image forming apparatus, that is, the photosensitive member drive motor 215, the polygon mirror drive motor of the scanning exposure apparatus 200, and other motors (not shown) that drive other parts of the image forming apparatus, actuators, and other power control mechanisms are controlled. Control is performed in an appropriate sequence by the main body control unit of the apparatus 220. The photoconductor drive motor 215 can output the rotation angle information of the photoconductor 210 and sends it to the recording device 221.

  In the image forming operation, image data from an external host (not shown) is received by the communication device 225, and the control device detects this and starts sequence control of each part of the image forming device including the image forming mechanism and the main body. The image data is sent to the rasterizer 223 by the data transfer mechanism of the control unit. The rasterizer 223 converts the image data into raster information suitable for the image forming apparatus and sends it to the image control unit of the control device 220.

  The image control unit of the control device 220 adjusts the raster information according to the control information and operation information of the main body from the main body control unit to form a video signal, and sends it to the laser driver 222. The laser driver 222 drives the laser diode of the scanning exposure apparatus 200 according to the video signal. Image exposure is performed on the photoreceptor 210 of the image forming mechanism controlled and driven by the control device 220 by the laser light modulated in accordance with the video signal.

  The control device performs a photoconductor inspection sequence based on the operation history of the main body and settings from the outside. In the photoconductor inspection sequence, at least the photoconductor 210 is rotationally driven, and the entire surface of the inspection area of the photoconductor 210 is scanned and exposed by the scanning exposure apparatus 200. At this time, the recording device sets the photosensor output of the scanning exposure device 220 to the entire circumference of the photosensitive member 210 according to the photosensitive member rotation angle information from the photosensitive member driving motor 215 and the scanning position information from the image control unit of the control device 220. It records over time. As a result, the optical sensor output related to the light scattering state of the entire surface of the inspection area of the photoconductor 210 can be recorded in the recording device 221 in association with the position on the surface of the photoconductor 210.

  By matching the reading / recording rate of the optical sensor output by the recording device 221 with the video rate for driving the laser diode at the time of image writing, the optical sensor output due to the surface state distribution of the photoreceptor 210 with the spatial resolution according to the image writing. Can be recorded.

  Along with the photoconductor inspection sequence, the main body control unit of the control device 220 analyzes the output information of the optical sensor recorded in the recording device 221 and extracts the position and state of the abnormality on the surface of the photoconductor 210, and the state, The type of abnormality is classified from the distribution shape and recorded together with the position information. Then, the degree of influence of each abnormality on the image and the degree of future deterioration are estimated, and a countermeasure method is determined and implemented. A processing example of the above process is shown below.

  First, in consideration of the fact that the optical sensor output for the same surface state differs depending on the scanning position, shading correction is performed to obtain a scattering intensity distribution.

  Next, from the scattering intensity distribution, the abnormality is detected, the type is determined, and the state is grasped and recorded based on the distribution state of the abnormal scattering. For example, an abnormality having a thin line distribution in the circumferential direction of the photoconductor is determined as a scratch, and the peak value of the scattering intensity is recorded. Abnormalities having a thick and broad linear distribution over the entire circumference are determined as poor cleaning, and the peak value and width of the scattering intensity are recorded. An irregular abnormality is determined as an adhering substance, and the peak value of the scattering intensity is recorded. A circular abnormality is determined as a spherical protrusion, and the diameter is recorded.

  Next, the status and timing of the manifestation of defects are evaluated. In the case of a flaw, the image defect occurrence time is estimated based on the table from the peak value of the scattering intensity. In the case of poor cleaning, the image defect occurrence time is estimated based on the table from the peak value and width of the scattering intensity. The deposits are classified into three types based on the table from the peak value of the scattering intensity: serious image defect, minor image defect, and no image defect. Spherical protrusions are classified into three types based on the table based on the diameter: serious image defect, minor image defect, and no image defect.

  Based on the above evaluation result, the control device implements the following abnormality countermeasures.

  The first is a countermeasure operation. If there is an image defect serious or image defect slight deposit, a photosensitive member cleaning sequence is executed only once for developing the toner band on the photosensitive member 210 and rotating the photosensitive member for a predetermined time without transferring. Test again. In addition, if there is a spherical protrusion at the same scanning direction position and there is a cleaning defect whose image defect occurrence time is estimated to be closer than a predetermined period, the cause of the cleaning defect can be considered as a blade scratch due to the spherical protrusion. If the system has a configuration in which the cleaning device can be displaced in the axial direction of the photosensitive member by an actuator (not shown) as a failure countermeasure mechanism, the cleaning failure deterioration preventing operation for slightly shifting the longitudinal position of the cleaning device 213 is executed.

  The second is a maintenance request. The maintenance request is made when there is an abnormality in which the image defect occurrence time is estimated to be closer than a predetermined period or is classified as serious image defect, and is made on the main body and via a communication line. On the main body, a warning message indicating that maintenance is necessary is displayed on the display device, and a list of abnormalities, a necessary countermeasure timing, and a countermeasure method are displayed by performing a predetermined operation. The warning performed via the communication line notifies a contact list on a preset communication line of a list of abnormalities, a necessary countermeasure timing, and a countermeasure method.

  The third is countermeasures against abnormalities during the image forming operation. When there are projections or deposits with serious image defects, the recording device 221 is referred to during the image forming operation, and the image formation start position is determined so that the projections are colored portions as much as possible and the white background portions are deposited. And avoiding the appearance of image defects.

  In the above configuration, it is recommended to use a history recording device that stores the results of a plurality of past inspection operations in time series together with the time when the inspection operation was performed and / or the operation history of the main body as the recording device 221. The As a result, it is possible to evaluate the time-series transition of the detected abnormality, and it becomes possible to determine the cause in more detail and to estimate the occurrence of a failure with higher accuracy.

  By adopting the above configuration, abnormalities on the surface of the photoreceptor 210 can be discovered before or immediately after a defect occurs, the abnormality is resolved as much as possible, optimal maintenance is possible, and the manifestation of the defect is avoided as much as possible. An image forming apparatus capable of doing this can be realized.

1 is a simplified diagram of a scanning exposure apparatus according to a first embodiment of the present invention. It is a simplified diagram of an image forming apparatus according to Embodiment 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Optical path of scanning exposure apparatus 102 Reflection and scattered light of scanning light impinging on an object to be scanned 111 Laser diode 112 Collimator lens 121 Photo detector 122 Condensing lens 131 Beam splitter 141 Polygon mirror 142 f-θ lens 200 Scanning type Exposure device 211 Charging roller 212 Developing device 213 Cleaning device 214 Mirror 215 Photoconductor drive motor 220 Control device 221 Recording device 222 Laser driver 223 Rasterizer 224 Display device 225 Communication device

Claims (3)

A scanning exposure apparatus including a light source and an optical scanning device that scans an object to be exposed within a predetermined range with light from the light source,
A beam splitter disposed between the light source and the optical scanning device, a condensing lens for condensing the scattered light from the exposure object taken out by the beam splitter, and the scattered light collected by the condensing lens A scanning type exposure apparatus, comprising: A photosensitive member is used as an image carrier, and an electrostatic latent image is formed by performing desired image exposure on the photosensitive member, and a colored toner is attached to the electrostatic latent image on the image carrier in a development process to form a toner image. An image forming apparatus having a process of visualizing and transferring the toner image onto a transfer material,
As a means for performing image exposure, a scanning exposure apparatus including a light source and an optical scanning device that scans the surface of the photoreceptor within a predetermined range with light from the light source is provided. The scanning exposure apparatus includes a light source and an optical scanning device. A beam splitter, a condenser lens that collects scattered light from the surface of the photoreceptor taken out by the beam splitter, and a photodetector that detects the scattered light collected by the condenser lens, Have
A recording apparatus that records information related to light scattering of the photosensitive member based on the detection signal of the photodetector and the operation information of the image forming apparatus, the operation of the image forming apparatus is changed based on the information of the recording apparatus, and the outside of the image forming apparatus And an image forming apparatus characterized by comprising:   The recording device is a history recording device that stores information related to light scattering on the surface of the photoreceptor in association with time and / or operation history based on a detection signal of a photodetector and operation information of the image forming apparatus. The image forming apparatus according to claim 2, wherein the control device changes the operation of the main body and issues a warning to the outside of the image forming apparatus based on information of the history recording apparatus.

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