JP2006181870A - Interval detection method and image-forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect an interval between a light source device and an image carrier unit. <P>SOLUTION: A second light beam B2 is projected at an angle different from that of a first light beam B1, an interval between detection patterns L1, L2 formed on a photosensitive drum 12 by the first light beam B1 and the second light beam B2 is detected, and then an interval between an LPH 16 and the photosensitive drum 12 is detected based on the detected interval between the detection patterns L1, L2. That is, used is such a fact that by projecting the first and second light beams B1, B2 at different angles, when the interval between the LPH 16 and the surface of the photosensitive drum 12 becomes longer or shorter, the interval between the detection patterns L1, L2 formed on the photosensitive drum 12 becomes longer or shorter. By using the above fact, it is possible to accurately detect the interval between the LPH 16 and the surface of the photosensitive drum 12 based on the interval between the detection patterns L1, L2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using a light source device including a light emitting element array including a plurality of light emitting elements and an image forming element array including a plurality of image forming elements, and an interval between the image carrier and the light source device. The present invention relates to a method and a configuration for detecting an error.

  Conventionally, a light emitting element array (for example, an LED array) arranged in series in the main scanning direction and controlled to blink by an image signal, and an image forming element array (for example, a cell) for forming an optical image of the light emitting element array 2. Description of the Related Art Image forming apparatuses (for example, copiers and printers) that perform image formation by exposing an image carrier on a light source device (for example, an LED print head) including a Fock lens array are widely used.

  In an LED print head using a Selfoc lens array, in order to realize a high-quality image, when mounting the LED print head and the image carrier, it is possible to suppress misalignment due to the mounting and obtain an appropriate focal length. Since it is important, the LED print head and the image carrier are attached with high accuracy on the basis of the apparatus main body.

Further, as a means for solving the problem that a stable spot size cannot be obtained because the distance between the image carrier and the LED print head varies depending on the rotation position of the image carrier because the image carrier is eccentric. In Document 1, an abutting member is provided on the LED print head, and the abutting member is brought into contact with the surface of the image carrier, so that the LED print head is always connected to the LED array in conjunction with the eccentricity of the image carrier. A configuration in which the interval between the image carriers is constant is disclosed.
Japanese Patent Laid-Open No. 5-19602

  However, in recent years, as the spot size with a high resolution has been reduced, the focal depth of the SELFOC lens array has become very narrow (about 40 to 50 μm) (at an opening angle of 20 °). If only the light source device and the image carrier are attached with high accuracy, an attachment error that affects the image quality occurs.

  Further, in the configuration in which the LED print head is provided with an abutting member to be brought into contact with the surface of the image carrier, the vibration of the image carrier is transmitted to the LED print head and density unevenness (Banding) occurs in the sub-scanning direction. .

  Therefore, in order to prevent banding, it is necessary to provide a configuration that maintains the distance between the LED print head and the image carrier with high accuracy without providing an abutting member. For this purpose, it is considered necessary to detect whether the distance between the LED print head and the image carrier is appropriate, and to adjust the distance between the LED print head and the image carrier based on the detection result.

  In consideration of the above-described facts, an object of the present invention is to accurately detect the distance between a light source device and an image carrier.

  According to a first aspect of the present invention, a plurality of light emitting elements that emit a first light beam and a plurality of connections that image the first light beam emitted from the light emitting element on the surface of the image carrier. And a light source device comprising: an image element; and irradiating the surface of the image carrier with a second light beam at an irradiation angle different from that of the first light beam, and the image carrier using the first light beam and the second light beam. An interval between the electrostatic latent images formed on the surface is detected, and an interval between the light source device and the surface of the image carrier is detected from the detected interval between the electrostatic latent images.

  In the above configuration, the second light beam is irradiated at an angle different from that of the first light beam, and the interval between the electrostatic latent images formed on the image carrier surface by the first light beam and the second light beam is detected, The interval between the light source device and the surface of the image carrier is detected from the detected interval between the electrostatic latent images.

  That is, in the above configuration, when the distance between the light source device and the surface of the image carrier becomes longer or shorter by irradiating the first light beam and the second light beam at different angles, the first light beam and This utilizes the fact that the interval between the electrostatic latent images formed on the surface of the image carrier by the second light beam is also increased or decreased.

  By utilizing this, the distance between the light source device and the surface of the image carrier can be accurately detected from the distance between the electrostatic latent images formed on the surface of the image carrier by the first light beam and the second light beam. .

  According to a second aspect of the present invention, in the configuration of the first aspect, an irradiation angle of the second light beam viewed from the main scanning direction is set to be the same as the first light beam, and the first light beam is set. And an interval in the main scanning direction of the electrostatic latent image formed on the surface of the image carrier by the second light beam, and the light source device and the image are detected from the detected interval in the main scanning direction of the electrostatic latent image. It is characterized by detecting the distance from the surface of the carrier.

  That is, in the above configuration, the irradiation angle viewed from the principal direction of the second light beam irradiated at an angle different from the first light beam is set to be the same as that of the first light beam, so that the light source device and the image carrier are As the interval with the surface becomes longer or shorter, the interval in the main scanning direction of the electrostatic latent image formed on the surface of the image carrier by the first light beam and the second light beam becomes longer or shorter. It is what you use. Therefore, the interval between the light source device and the surface of the image carrier can be accurately detected by detecting the interval in the main scanning direction of the electrostatic latent image.

  If the first light beam and the second light beam have different irradiation angles, basically the same effect can be obtained regardless of the irradiation direction, but the interval in the sub-scanning direction of the electrostatic latent image In the case of detection by the error, an error is likely to occur in the detection result due to the influence of the R surface of the image carrier. Accordingly, by detecting the electrostatic latent image at the interval in the main scanning direction as in the above configuration, the interval between the light source device and the surface of the image carrier can be detected with high accuracy.

  According to a third aspect of the present invention, in the configuration of the first or second aspect, the electrostatic latent image is detected by detecting an interval between toner images formed by developing the electrostatic latent image. It is characterized by detecting the interval of.

  According to the above configuration, the electrostatic latent image formed on the surface of the image carrier is developed by the first light beam and the second light beam, and the interval between the toner images formed by the development is detected, so that Thus, the interval between the electrostatic latent images can be detected, and the interval between the light source device and the surface of the image carrier can be detected from the interval between the electrostatic latent images.

  In the invention according to claim 4 of the present invention, a plurality of arranged light emitting elements that emit the first light beam and a plurality of connections that image the first light beam emitted from the light emitting element on the surface of the image carrier. A light source device provided with an image element, a light irradiation means provided in the light source device, for irradiating the surface of the image carrier with a second light beam at an irradiation angle different from that of the first light beam, and the first light. Detecting means for detecting an interval between the electrostatic latent images formed on the surface of the image carrier by the beam and the second light beam, and the light source device and the image based on the interval between the electrostatic latent images detected by the detecting means. And a calculation means for calculating a distance from the surface of the carrier.

  According to the above configuration, the surface of the image carrier is irradiated with the second light beam at a different irradiation angle from the first light beam irradiated from the light emitting element of the light source device by the light irradiation means provided in the light source device.

  Then, the interval between the electrostatic latent images formed on the surface of the image carrier by the first light beam and the second light beam is detected by the detecting means, and the light source device and the image carrier are detected based on the interval between the electrostatic latent images. The distance from the surface is calculated by the calculation means.

  That is, in the above configuration, when the distance between the light source device and the surface of the image carrier becomes longer or shorter by irradiating the first light beam and the second light beam at different angles, the first light beam and This utilizes the fact that the interval between the electrostatic latent images formed on the surface of the image carrier by the second light beam is also increased or decreased.

  By utilizing this, the distance between the light source device and the surface of the image carrier can be accurately detected from the distance between the electrostatic latent images formed on the surface of the image carrier by the first light beam and the second light beam. .

  In the invention according to claim 5 of the present invention, in the configuration of claim 4, the detection means detects the electrostatic image by detecting an interval between toner images formed by developing the electrostatic latent image. It is characterized by detecting the interval between latent images.

  According to the above configuration, the interval between the toner images formed by developing the electrostatic latent image formed on the surface of the image carrier by the first light beam and the second light beam is indirectly detected. The interval between the electrostatic latent images can be detected, and the interval between the light source device and the surface of the image carrier can be detected from the interval between the electrostatic latent images.

  The invention according to claim 6 of the present invention is characterized in that, in the configuration of claim 4 or claim 5, the light irradiation means is detachably provided in the light source device.

  In order to manufacture an image forming apparatus at a low cost, it is indispensable to reduce the number of parts as much as possible. The light irradiation means for forming the second beam having a different irradiation angle with respect to the first light beam detects the distance between the surface of the light source device and the image carrier, and based on the result, the distance between the light source device and the surface of the image carrier. After adjusting, it is unnecessary if the interval is maintained. Therefore, it is possible to reduce the cost by providing the light irradiating means in the light source device so that it can be removed, used when assembling, and removing it when shipped to the market.

  According to a seventh aspect of the present invention, in the configuration according to any one of the fourth to sixth aspects, a light emitting element is arranged in the light irradiation means in parallel with the light emitting element that emits the first beam. It is characterized by.

  The light emitting elements are arranged in the light irradiation means in parallel with the light emitting elements that emit the first beam. In other words, the light emitting elements are arranged in the same direction (for example, main scanning direction) as the light emitting elements that emit the first beam. As described above, by using the light emitting elements arranged in the same manner, an image forming apparatus can be manufactured at low cost.

  The invention according to claim 8 of the present invention is characterized in that, in the configuration of any one of claims 4 to 7, display means for displaying a result calculated by the calculation means is provided.

  In the above configuration, display means for displaying the result calculated by the calculation means is provided. Therefore, the user or the like can see the displayed result, and the distance between the light source device and the surface of the image carrier can be adjusted based on the result. If the distance between the light source device and the surface of the image carrier is adjusted to an optimum distance, even if the spot size is a small diameter, a high-quality image can be realized without misalignment.

  According to a ninth aspect of the present invention, in the configuration according to any one of the fourth to eighth aspects, the distance between the light source device and the surface of the image carrier is calculated based on the result calculated by the calculating means. It is characterized by having an interval adjusting means for adjusting.

  According to the above configuration, since the interval between the light source device and the surface of the image carrier can be adjusted by the interval adjustment unit based on the result calculated by the calculator, the distance between the light source device and the surface of the image carrier can be adjusted. Adjustment is easy.

  According to a tenth aspect of the present invention, in the configuration according to the ninth aspect, the adjusting means includes a screw portion that supports the light source device on a main body frame of the image forming apparatus, and a motor that rotates the screw portion, Control means for controlling the amount of rotation of the motor from the difference between the calculated value calculated and a predetermined value specified in advance is provided.

  In the above configuration, the rotation amount of the motor constituting the adjusting unit is controlled by the control unit from the difference between the calculated calculation value and the predetermined specified value. For this reason, even if a temperature change or installation movement occurs in the image forming apparatus, and the interval between the light source device and the surface of the image carrier changes, it is automatically controlled, and the light source device and the surface of the image carrier are always controlled. The interval can be kept optimal.

  According to an eleventh aspect of the present invention, in the configuration according to the tenth aspect, the control means controls the rotation amount of the motor based on an interval variation pattern with the light source device in one rotation of the image carrier. Features.

  In the above configuration, since the rotation amount of the motor is controlled based on the interval variation pattern with the light source device in one rotation of the image carrier, the image carrier is decentered, and the surface of the light source device and the image carrier is rotated depending on the rotational position. Even when the distance varies, the distance between the light source device and the surface of the image carrier can always be kept optimal.

  According to a twelfth aspect of the present invention, in the configuration according to any one of the fourth to eighth aspects, a light amount for adjusting a light amount of a light emitting element of the light irradiation unit based on a detection result calculated by the calculation unit. An adjustment means is provided.

  When the distance between the light source device and the surface of the image carrier deviates from an appropriate value, the spot size increases. For example, when a line of one pixel is irradiated, the latent image potential cannot be achieved to the development threshold level and development is performed. It may not be possible. In the above configuration, since the light amount of the light emitting element of the light irradiation unit can be adjusted by the light amount adjusting unit, the distance between the light source device and the surface of the image carrier is in accordance with the amount of deviation that deviates from the appropriate value. Thus, it is possible to develop a line of one pixel by increasing the light amount of each pixel.

  According to a thirteenth aspect of the present invention, in the configuration according to the twelfth aspect, the light amount adjusting means determines the light amount of the light emitting element based on an interval variation pattern with the light source device in one rotation of the image carrier. It is characterized by that.

  In the above configuration, since the light amount of the light emitting element of the light irradiating means is determined based on the interval variation pattern with the light source device in one rotation of the image carrier, the image carrier is decentered and the light source device and the image are rotated according to the rotational position. Even if the distance between the surfaces of the carrier fluctuates, the light quantity of the light emitting element of the light irradiation means can always be kept optimal.

  According to a fourteenth aspect of the present invention, in the configuration according to any one of the fourth to thirteenth aspects, the detection means is formed on each of a plurality of image carriers by a plurality of light source devices. A sensor that detects color misregistration from a pattern is used.

  The detection means for detecting the interval between the electrostatic latent images formed on the surface of the image carrier by the first light beam and the second light beam is formed on each of the plurality of image carriers by each of the plurality of light source devices. Since a sensor that detects color misregistration from the pattern is used, parts can be shared and the cost of the image forming apparatus can be reduced.

  Since the present invention is configured as described above, the distance between the light source device and the image carrier can be accurately detected.

  One embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a schematic configuration of an image forming apparatus 10 according to the present embodiment.

  As shown in FIG. 1, the image forming apparatus 10 includes an apparatus housing 30, and the apparatus housing 30 is provided with a photosensitive drum 12 that rotates at a constant speed in an arrow B direction. The rotation direction (arrow B direction) of the photosensitive drum 12 corresponds to the sub-scanning direction. Around the photosensitive drum 12, along the rotation direction of the photosensitive drum 12, a charger 14, an LED print head (hereinafter referred to as LPH) 16 as a light source device, a developing device 18, a transfer roller 20, a cleaner ( An erase lamp (not shown) is sequentially arranged.

  After the surface of the photosensitive drum 12 is uniformly charged by the charger 14, an electrostatic latent image is formed on the photosensitive drum 12 by the light beam B1 emitted from the LPH 16.

  Toner is supplied from the developing unit 18 to the formed electrostatic latent image, and a toner image is formed on the photosensitive drum 12. The toner images on the photosensitive drum 12 are transferred one by one from the paper tray 22 by the transfer roller 20 and transferred onto the paper 26 that has been transported by the paper transport belt 24. The toner remaining on the photosensitive drum 12 after the transfer is removed by a cleaner (not shown), neutralized by an erase lamp (not shown), charged by the charger 14 again, and the same processing is repeated.

  On the other hand, the paper 26 onto which the toner image has been transferred is conveyed to a fixing device 28 including a pressure roller 28A and a heating roller 28B, and subjected to a fixing process. As a result, the toner image is fixed and a desired image is formed on the paper 26. The paper 26 on which the image is formed is discharged out of the apparatus housing 30. A series of image formation is performed as described above.

  A sensor 29 is disposed above the sheet conveying belt 24 between the photosensitive drum 12 and the driving roller 27. The sensor 29 reads a later-described toner image line (detection pattern) transferred onto the paper transport belt 24, and detects the interval between the detection patterns. After this detection, the detection pattern transferred onto the paper transport belt 24 is cleaned by the cleaner 15. The apparatus housing 30 is provided with a monitor (display means) 57.

  Next, the configuration of the LPH 16 will be described with reference to FIGS.

  FIG. 2 shows a configuration diagram of the LPH 16 viewed from the main scanning direction.

  As shown in FIG. 2, the LPH 16 forms an image on the surface of the photosensitive drum 12 with the LED array 32, the printed circuit board 40 that supports the LED array 32, and the first light beam B <b> 1 emitted from the LED array 32. The SELFOC lens array 34 is provided.

  The printed board 40 is disposed in the housing 36 with the mounting surface of the LED array 32 facing the photosensitive drum 12.

  As shown in FIG. 3, the printed circuit board 40 includes a shift register 42 that stores image data for one line, a latch circuit 44, and a driver 46.

  The LEDs 48 of the LED array 32 connected to the driver 46 are provided for the number of pixels (dots) corresponding to the resolution. For example, the LEDs 48 correspond to A3 size (420 mm, 297 mm) paper, and 600 dpi in the main scanning direction. In the case of printing, about 7020 are provided. The LEDs 48 are arranged in a line along a direction (main scanning direction) orthogonal to the rotation direction (sub-scanning direction) of the photosensitive drum 12.

  The printed circuit board 40 is connected to the control device 50, and the control device 50 sends image data for one line (pixel data for 7020 dots in the above example) to the shift register 42 in synchronization with the transfer clock. When the image data for one line is output to the shift register 42, the SET signal is output to the latch circuit 44. As a result, the image data for one line stored in the shift register 42 is latched in the latch circuit 44.

  When the control device 50 outputs the STROB signal to the driver 46, the driver 46 supplies the LED 48 with a current having a current value corresponding to the corresponding pixel data. At this time, each driver 46 adjusts the output current based on correction data for correcting the amount of light emitted from the LED 48. Each LED 48 emits light according to the current value of the current output from the driver, and the photosensitive drum 12 is exposed to form an electrostatic latent image corresponding to one line of image data on the photosensitive drum 12. Is done.

  Next, a light irradiation device (light irradiation means) that is provided with the LPH 61 and that irradiates the photosensitive drum 12 with the second light beam at an angle different from the first light beam B1 will be described.

  4 is a sectional view of the photosensitive drum 12 and the LPH 16 as viewed from a direction (sub-scanning direction) perpendicular to the rotation axis of the photosensitive drum 12, and FIG. The enlarged view of the structure of the dashed-dotted line part) is shown.

  As shown in FIG. 5, a light irradiation device (light irradiation means) 61 including an LD and a collimator is disposed at one end of the LPH 16. The second light beam B2 is emitted from the LD of the light irradiation device 61, the second light beam B2 passes through the collimator and reaches the photosensitive drum 12, and an electrostatic latent image is formed on the surface of the photosensitive drum 12. The

  Further, the light irradiation device 61 is arranged to be inclined inward by θ degrees with respect to the first light beam B1, and the emission surface side of the light irradiation device 61 faces the central portion of the photosensitive drum 12. For this reason, the second light beam B2 emitted from the LD of the light irradiation device 61 is irradiated at an irradiation angle inclined inward by θ ° with respect to the first light beam B1. The irradiation angle of the second light beam B2 viewed from the main scanning direction is set to be the same as that of the first light beam B1.

  When detecting the interval between the LPH 16 and the surface of the photosensitive drum 12, a detection pattern L 1 is formed along the sub-scanning direction by the first light beam B 1 emitted from the LED array 32, and the light irradiation device 61 emits the light. The detection pattern L2 along the sub-scanning direction is formed by the second light beam B2.

  Then, the detection patterns L1 and L2 are developed by the developing unit 18, the developed detection patterns L1 and L2 are transferred to the paper transport belt 24, and the detection pattern L1 is detected by a sensor (detection means) 29 as shown in FIG. , L2 is detected in the main scanning direction.

  The detection patterns L1 and L2 may be transferred to the paper 26 instead of the paper transport belt 24 to detect the interval therebetween.

  Also, as shown in FIG. 7, an image forming apparatus that primarily transfers the toner image formed on the photosensitive drum 12 to the intermediate transfer belt 56 and secondarily transfers the primary transferred toner image to the paper 26. 13, the developed detection patterns L 1, L 2 are transferred to the intermediate transfer belt 56, and when the interval between the detection patterns L 1, L 2 is detected by the sensor (detection means) 71 at the stage of being transferred to the intermediate transfer belt 56. I do not care.

  Further, as shown in FIG. 7, in the image forming apparatus 13 that forms an image with the photosensitive drum 12 for each color, a color shift sensor for detecting a color shift between the colors is used to detect the detection patterns L1 and L2. The sensor 71 can be used. In this way, parts can be shared and low cost can be realized.

  Furthermore, it is also possible to detect the detection patterns L1 and L2 of the latent image state on the photosensitive drum 12.

  As shown in FIG. 5, when the distance between the detection pattern L1 and the detection pattern L2 is A when the target value (ideal value) is the distance between the LPH 61 and the surface of the photosensitive drum 12, the LPH 61 and the photosensitive drum 12 are used. When the distance between the surface of the photosensitive drum 12 is shorter than the target value, the distance between the detection patterns L1 and L2 is longer than A. Conversely, when the distance between the surface of the LPH 61 and the photosensitive drum 12 is longer than the target value, the detection pattern is detected. The interval between L1 and L2 is shorter than A (this relationship is shown in FIG. 8).

  By utilizing this, it is possible to accurately detect the interval between the LPH 16 and the surface of the photosensitive drum 12 from the interval between the detection patterns L1 and L2.

  Further, since the detection is performed based on the interval between the detection patterns L1 and L2 in the main scanning direction, the detection is not affected by the R surface of the photosensitive drum 12 as in the case where detection is performed at the interval in the sub scanning direction of the electrostatic latent image. There is no error in the detection result.

  Although one end portion side of the LPH 16 has been described, a light irradiation device is similarly provided at the other end portion, and the interval between both end portions of the LPH 16 is detected, and the interval between the LPH 16 and the surface of the photosensitive drum 12 is adjusted as will be described later. In this case, the distance between the LPH 16 and the photosensitive drum 12 can be set to a target value uniformly in the main scanning direction.

  The light irradiation device 61 can obtain the same effect regardless of whether it is fixed or detachable. However, in order to provide a low-cost image forming apparatus, it is essential to reduce the number of components as much as possible. Therefore, it is preferable that the light irradiation device 61 is detachably provided on the LPH 16.

  In this way, after adjusting the distance between the LPH 16 and the photosensitive drum 12 to a target value, if the distance is maintained, the light irradiation device 61 is unnecessary, and therefore, the LPH 16 is used at the time of assembly. It is possible to reduce the cost by adjusting the distance between the photosensitive drum 12 and the photosensitive drum 12 and removing it when shipped to the market.

  In the case of an image forming apparatus that requires replacement of the LPH 16 in the market, in the configuration in which the light irradiation device 61 is removed after the assembly of the image forming device is completed, the light irradiation is performed again when the interval between the LPH 16 and the photosensitive drum 12 is adjusted to a target value. It is necessary and troublesome to install the device 61.

  Therefore, as shown in FIG. 9, the LED array 58 is similarly arranged in the main scanning direction adjacent to the LED array 32, and the second light beam B <b> 2 emitted from the LED array (LED) 58 is reflected by the reflection mirror 60. Then, the light is reflected by the concave mirror 62, and the photosensitive drum 12 is irradiated with an inclination of θ ° with respect to the first light beam B1. Thus, by using the LED array 58 arranged in the same manner as the LED array 32, the cost can be reduced.

  Next, display means for displaying the detection result between the detection patterns L1 and L2, and interval adjustment means for adjusting the interval between the LPH 16 and the surface of the photosensitive drum 12 from the detection result between the detection patterns L1 and L2 will be described. To do.

  As described above, the monitor (display unit) 57 is provided in the apparatus housing 13 (see FIG. 1), and the operator can easily recognize the result of detecting the interval between the detection patterns L1 and L2 by the sensor 29. And displayed on the monitor 57. Further, if the value obtained by calculating the necessary adjustment amount of the LPH 16 from the result of detecting the interval between the detection patterns L1 and L2 is displayed, the operation is performed when the interval between the LPH 16 and the surface of the photosensitive drum 12 is adjusted. Efficiency is improved.

  As shown in FIGS. 5 and 9, a spacer 54 is provided between the protrusion 50 provided at one end of the LPH 16 and the main body frame 52. By changing the thickness of the spacer 54, the distance between the LPH 16 and the surface of the photosensitive drum 12 can be adjusted. That is, the operator confirms the necessary adjustment amount on the monitor 57, and performs the adjustment by changing to the spacer 54 having a thickness necessary for the distance between the LPH 16 and the surface of the photosensitive drum 12 to be a target value.

  A stepping motor can be used as an interval adjusting means for adjusting the interval between the LPH 16 and the surface of the photosensitive drum 12. As shown in FIG. 10, a stepping motor 64 in which an abutting member 66 is provided with respect to the main body frame 52 is incorporated at the end of the LPH 16.

  In this stepping motor 64, it is possible to adjust the distance between the LPH 16 and the surface of the photosensitive drum 12 by rotating the abutting portion 66 to expand and contract.

  Next, the control part which adjusts the rotation amount of Stepingmotor 64 is demonstrated based on FIG.

  As shown in FIG. 11, when image data and detection data are input to a control unit (control means) 80 and a driving circuit 82 of the photosensitive drum 12, the photosensitive drum 12 to which the image data is input is rotationally driven. Then, the control unit 80 having the image data and the detection data inputs the detection pattern creation signal to the LD drive circuit 84 of the light irradiation device 61 and the image pattern creation signal to the drive circuit 86 of the LED 48 of the LPH 16.

  As a result, the LD is driven to irradiate the photosensitive drum 12 with the second light beam B2, and the detection pattern L2 is formed on the photosensitive drum 12. Further, the LED 48 is driven to irradiate the photosensitive drum 12 with the first light beam B1, and the detection pattern L1 is formed on the photosensitive drum 12.

  The detection patterns L 1 and L 2 are detected by the sensor 29, and detection data at intervals between the detection patterns L 1 and L 2 is input to the control unit 80. The control unit 80 to which the detection data is input compares the detection data with a predetermined value A set in advance by the comparison circuit (calculation means), and the calculation circuit (calculation means) requires the LPH 16 based on the comparison result. The adjustment amount is calculated, and the calculated value is stored in the storage circuit. Then, the control unit 80 inputs a height adjustment control signal based on the necessary adjustment amount calculated by the calculation circuit to the drive circuit of the Steping motor 64. Thereby, the Steping motor 64 rotates the abutting member 66 and adjusts the distance between the LPH 16 and the surface of the photosensitive drum 12.

  By controlling the distance between the LPH 16 and the photosensitive drum 12 in this way, for example, even if a temperature change or installation movement occurs and the distance between the LPH 16 and the photosensitive drum 12 varies, the LPH 16 and the photosensitive drum 12 are frequently changed. The distance between the drum 12 can be detected and the result can be fed back to automatically adjust the distance between the LPH 16 and the photosensitive drum 12, and the distance between the LPH 16 and the photosensitive drum 12 can always be kept optimal.

  Next, a configuration for correcting the gap between the LPH 16 and the photosensitive drum 12 by the eccentricity of the photosensitive member 12 will be described.

  As shown in FIG. 12, the light irradiation devices 61 are arranged at both ends of the LPH 16 to detect the distances K and M between the detection patterns L <b> 1 and L <b> 2 formed at both ends of the photosensitive drum 12.

  Further, a rotary encoder (rotation detector) is attached to the rotation shaft of the photoconductive drum 12, and based on the rotation position (rotation angle) signal of the photoconductive drum 12 from the rotary encoder, as shown in FIG. A pattern for detecting the interval between the carriers is formed, and the data is stored. By feeding back the result so that the distance between the LPH 16 and the image carrier becomes a target value and controlling the amount of rotation of the Stepping motor 64 based on the reference signal, the distance between the LPH 16 and the photosensitive drum 12 can be kept constant. It is possible to obtain a stable small-diameter beam.

  As described above, in the configuration in which the stepping motor 64 and the like are provided and the distance between the LPH 16 and the photosensitive drum 12 is adjusted, the number of parts increases, so that the apparatus becomes large.

  Therefore, instead of the configuration for adjusting the interval between the LPH 16 and the photosensitive drum 12, a configuration in which the light quantity of the LED 48 is adjusted according to the interval between the LPH 16 and the photosensitive drum 12 is conceivable.

  Also in this case, as in the case of adjusting the interval between the LPH 16 and the photosensitive drum 12, detection data of the interval between the detection patterns L 1 and L 2 detected by the sensor 29 is input to the control unit 80. The control unit 80 to which the detection data is input compares the detection data with a predetermined value A set in advance by the comparison circuit (calculation means), and the calculation circuit (calculation means) requires the LED 48 based on the comparison result. The amount of light is calculated, and the calculated value is stored in the storage circuit. Then, the control unit 80 inputs light amount correction data based on the necessary light amount calculated by the calculation circuit to the driver 46 of the printed circuit board 40. The driver 46 adjusts the output current to the LED 48, and the light quantity of the LED 48 is adjusted (see FIG. 3).

  If the distance between the LPH 16 and the photosensitive drum 12 deviates from the target value, the spot size increases. For example, when a line of one pixel is irradiated, the latent image potential cannot be achieved to the development threshold level and development cannot be performed. End up. As described above, it is possible to develop a line of one pixel by increasing the light amount of each pixel according to the amount by which the distance between the LPH 16 and the photosensitive drum 12 is deviated from the target value. Further, it is possible to compensate for image quality deterioration without increasing the number of parts.

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the internal configuration of the LPH according to the embodiment of the present invention. FIG. 3 is a block diagram showing a schematic circuit configuration on the printed circuit board according to the embodiment of the present invention. FIG. 4 is a cross-sectional view of the photosensitive drum and LPH viewed from a direction orthogonal to the rotation axis of the photosensitive drum according to the embodiment of the present invention. FIG. 5 is an enlarged view of the configuration of one end of FIG. FIG. 6 is a diagram illustrating a sensor that detects a detection pattern according to an embodiment of the present invention. FIG. 7 is a graph showing the interval between the photoconductor and LPH and the interval between detection patterns according to the embodiment of the present invention. FIG. 8 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 9 is a cross-sectional view showing the internal configuration of the LPH according to the embodiment of the present invention. FIG. 10 is a cross-sectional view showing the internal configuration of the LPH according to the embodiment of the present invention. FIG. 11 is a control diagram according to the embodiment of the present invention. FIG. 12 is a plan view showing an LPH according to the embodiment of the present invention. FIG. 13 is a graph showing the interval between the photoconductor and LPH and the interval between detection patterns.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 13 Image forming apparatus 16 LPH (light source device)
29 Sensor (detection means)
46 Driver (Light intensity adjustment means)
54 Spacer (Spacing adjustment means)
57 Monitor (display means)
61 Light irradiation device (light irradiation means)
64 Stepingmotor (interval adjustment means)
71 Sensor (detection means)

Claims (14)

A plurality of light emitting elements arranged to emit the first light beam;
A plurality of imaging elements that image the first light beam emitted from the light emitting element on the surface of the image carrier, and a light source device comprising:
Irradiating the surface of the image carrier with the second light beam at an irradiation angle different from that of the first light beam;
Detecting an interval between electrostatic latent images formed on the surface of the image carrier by the first light beam and the second light beam;
An interval detection method comprising detecting an interval between the light source device and the surface of the image carrier from an interval between the detected electrostatic latent images. An irradiation angle of the second light beam viewed from the main scanning direction is set to be the same as that of the first light beam,
Detecting an interval in the main scanning direction of the electrostatic latent image formed on the surface of the image carrier by the first light beam and the second light beam;
The interval detection method according to claim 1, wherein the interval between the light source device and the surface of the image carrier is detected from the interval in the main scanning direction of the detected electrostatic latent image.   The interval detection according to claim 1, wherein the interval between the electrostatic latent images is detected by detecting an interval between toner images formed by developing the electrostatic latent image. Method. A light source device comprising: a plurality of arranged light emitting elements that emit a first light beam; and a plurality of imaging elements that form an image of the first light beam emitted from the light emitting element on an image carrier surface;
A light irradiating means provided on the light source device for irradiating the surface of the image carrier with a second light beam at an irradiation angle different from that of the first light beam;
Detecting means for detecting an interval between electrostatic latent images formed on the surface of the image carrier by the first light beam and the second light beam;
A calculation means for calculating a distance between the light source device and the surface of the image carrier from an interval between the electrostatic latent images detected by the detection means;
An image forming apparatus comprising:   5. The detection unit according to claim 4, wherein the detection unit detects an interval between the electrostatic latent images by detecting an interval between toner images formed by developing the electrostatic latent image. Image forming apparatus.   The image forming apparatus according to claim 4, wherein the light irradiation unit is detachably provided in the light source device.   7. The image forming apparatus according to claim 4, wherein the light emitting unit includes a light emitting element arranged in parallel with the light emitting element that emits the first beam. 8.   The image forming apparatus according to claim 4, further comprising a display unit configured to display a result calculated by the calculation unit.   9. The image according to claim 4, further comprising an interval adjusting unit that adjusts an interval between the light source device and a surface of the image carrier based on a result calculated by the calculating unit. Forming equipment. The adjusting means includes a screw part that supports the light source device on the main body frame of the image forming apparatus, and a motor that rotates the screw part.
The image forming apparatus according to claim 9, further comprising a control unit that controls a rotation amount of the motor based on a difference between the calculated calculated value and a predetermined specified value.   The image forming apparatus according to claim 10, wherein the control unit controls a rotation amount of the motor based on an interval variation pattern with respect to the light source device in one rotation of the image carrier.   The image forming apparatus according to claim 4, further comprising a light amount adjusting unit that adjusts a light amount of a light emitting element of the light irradiation unit based on a detection result calculated by the calculating unit.   The image forming apparatus according to claim 12, wherein the light amount adjusting unit determines a light amount of the light emitting element based on an interval variation pattern with respect to the light source device in one rotation of the image carrier.   14. The sensor according to claim 4, wherein a sensor that detects a color shift from a pattern formed on each of the plurality of image carriers in each of the plurality of light source devices is used as the detection unit. The image forming apparatus described in the item.

Images