JP2014063122A - Optical sensor and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sensor which prevents toner or dust in the air from being deposited during detecting density of an image formed on an image carrier and a position of an image end, and to provide an image forming device.SOLUTION: Toner or dust in the air can be prevented from being deposited on a sensor part 21 by covering the periphery of the sensor part 21 for detecting an image pattern with a cylindrical member 22. The cylindrical member 22 is rotated by transparent cylindrical rotating members 23, 24, to remove the matter deposited on the outer surface thereof with a brush 25.

Description

  The present invention relates to an optical sensor that detects an object to be detected and an image forming apparatus including the optical sensor.

  Conventionally, for example, an image density detection pattern or an image position deviation detection pattern is formed on an image carrier, and these patterns are read as an object to be detected by an optical sensor to correct image density and image writing timing. The device is known.

  Some image forming apparatuses of this type include a cleaning mechanism that removes toner and floating dust attached to optical components such as a light source and a light receiving unit of an optical sensor.

  For example, Patent Document 1 records a shutter 15 for preventing scattered toner and the like from adhering to the detection surface 14a of the image density detection device 14 capable of detecting the density detection pattern formed on the intermediate transfer belt 5, and recording the shutter 15. It is described that a compression spring 17 is provided in conjunction with the operation of the medium transfer device 11.

  However, in the image density detection device of the intermediate transfer device described in Patent Document 1, the shutter 15 having the cleaning member is provided on the front surface of the detection surface 14a, and cleaning is performed by moving the shutter 15. It is possible only before and after detection pattern detection, and it has been impossible to prevent toner or floating dust that has been peeled off from the image carrier during density detection pattern detection from adhering to the optical component or to clean the optical component.

  The present invention aims to solve such problems.

  That is, an object of the present invention is to provide an optical sensor and an image forming apparatus that can prevent the adhesion of dust such as toner and floating dust during the detection operation of an object to be detected.

  In order to solve the problems described above, the invention described in claim 1 is an optical sensor having a sensor unit that is fixed so as to face the object to be detected and detects the object by irradiating light. A cylindrical member formed of a material that allows the curved surface to intersect the optical path of the light emitted from the sensor unit and that transmits the light; and a rotating member that rotates the cylindrical member; A cleaning member that is provided at a position that does not block the optical path and that removes deposits attached to the outer surface of the cylindrical member.

  According to the first aspect of the present invention, by covering the periphery of the sensor unit that detects the object to be detected with the cylindrical member that is formed of a material that transmits the light emitted by the sensor unit, toner and floating on the sensor unit are covered. Adherence of dust such as dust can be prevented. In addition, because the cylindrical member is rotated by the rotating member and the adhering matter adhering to the surface of the cylindrical member is removed by the cleaning member, the cylindrical surface can be cleaned without blocking the optical path of the sensor. The cleaning operation can be performed.

1 is a side view of an optical sensor according to a first embodiment of the present invention. FIG. 2 is a front view of the optical sensor shown in FIG. 1. It is a principal part block diagram of the image forming apparatus which has the optical sensor shown by FIG. It is a side view of the optical sensor concerning the 2nd Embodiment of this invention. It is a side view of the other example of the optical sensor concerning the 2nd Embodiment of this invention. It is a side view of the other example of the optical sensor concerning the 2nd Embodiment of this invention. It is a side view of the optical sensor concerning the 3rd Embodiment of this invention. It is a flowchart which shows the control operation of the optical sensor shown by FIG. It is a flowchart which shows the control action of the optical sensor concerning the 4th Embodiment of this invention.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a side view of an optical sensor according to a first embodiment of the present invention. FIG. 2 is a front view of the optical sensor shown in FIG. FIG. 3 is a configuration diagram of a main part of the image forming apparatus having the optical sensor shown in FIG.

  1 and 2 show an optical sensor 20 according to a first embodiment of the present invention. The optical sensor 20 includes a sensor unit 21, a transparent cylinder 22, transparent cylinder rotating members 23 and 24, a brush 25, transparent cylinder support members 26 and 27, and a fixing unit 28.

  The optical sensor 20 is an endless belt-like intermediate transfer belt 5 as an image carrier on which an image pattern (hereinafter simply referred to as an image pattern) for detecting the density of an image to be detected and the position of the image edge is formed. It is provided so as to face the surface 5a. In addition, the code | symbol 7 of FIG. 1 is a rotation roller, and the code | symbol 11 is a transfer roller. Then, a recording medium such as paper passes between the transfer roller 11 and the intermediate transfer belt 5, so that the image formed on the intermediate transfer belt 5 is transferred to the recording medium.

  The sensor unit 21 includes a light source that emits light, a light receiving unit that receives light emitted from the light source reflected by the object to be detected, and the like. Then, the intensity of light received by the light receiving unit is converted into an electrical signal and output to a control device (not shown). The sensor unit 21 is formed in a groove shape, and is fixed to a fixing unit 28 extending in a direction parallel to the intermediate transfer bell 5 and the surface 5a of the 5 by screwing or the like.

  The transparent cylinder 22 is a transparent cylindrical member formed in a thin shape with a transparent resin or the like, and accommodates the sensor unit 21 so that the optical path of light irradiated by the sensor unit 21 intersects the curved surface of the transparent cylinder 22. . Transparent cylinder support members 26 and 27 are provided at both ends of the transparent cylinder 22 so that the transparent cylinder 22 can be rotated on a rotation axis parallel to the intermediate transfer belt 5 by transparent cylinder rotating members 23 and 24 described later. It has been. The transparent cylinder 22 is not limited to being transparent as long as light from the sensor unit 21 can be transmitted. For example, when using infrared light, it is not necessary to be transparent. In other words, it may be formed of a material that transmits the light emitted from the sensor unit 21.

  As represented by the Fresnel equation, light is reflected on the surface of the transparent cylinder 22 even if the incident angle of the light to the transparent cylinder 22 is small. Reflection causes light attenuation, and the amount of light received decreases. Further, the reflected light from the transparent cylinder 22 enters the light receiving portion as stray light, causing a decrease in detection accuracy. These phenomena occur particularly noticeably when the gloss of the transparent cylinder 22 is uneven. Therefore, in order to eliminate the gloss unevenness of the transparent cylinder 22 and prevent a reduction in the amount of reflected light, the transparent cylinder 22 may be subjected to an optical coating process such as an AR (Anti Reflective) coat. That is, the surface of the cylindrical member may be subjected to a treatment for preventing light reflection.

  The transparent cylindrical support members 26 and 27 as support members enter the transparent cylinder 22 and rotate to rotate the transparent cylinder 22 connected to the small diameter portions 26a and 27a that rotatably support the transparent cylinder 22 and the small diameter portions 26a and 27a. The large-diameter portions 26b and 27b restrict the movement in the direction parallel to the axis. In addition, the transparent cylindrical support members 26 and 27 are provided with holes through which the fixing portion 28 passes, and the positions thereof are fixed by the fixing portion 28. Thus, by fixing the positions of the transparent cylinder support members 26 and 27, the transparent cylinder 22 can be positioned so as to accommodate the sensor unit 21 near the center in the axial direction of the transparent cylinder 22.

  The transparent cylinder rotating members 23 and 24 are configured by rollers, rollers, or the like having a smaller diameter than the transparent cylinder 22. The transparent cylindrical rotating members 23 and 24 are provided at a position where the optical path of the sensor unit 21 is not obstructed by being provided below the transparent cylinder 22 in FIGS.

  One of the transparent cylindrical rotating members 23 and 24 is rotated by a drive motor or the like (not shown), and the other is a driven rotating member rotated by the transparent cylinder 22 rotated by one rotating member. In addition, as shown in FIG. 2, the transparent cylindrical rotating members 23 and 24 contact the outer surfaces of both ends of the transparent cylinder 22 with rollers or the like, so that toner or floating dust adhering to the rollers or the like enters the transparent cylinder 22. It can prevent adhering and having a bad influence on the optical path of sensor part 21.

  The brush 25 as a cleaning member (brush member) has a bristle brush formed in the circumferential direction of a cylindrical central member that is rotatable along a rotation axis parallel to the rotation axis of the transparent cylinder 22. The brush 25 is formed to have a width substantially the same as the width of the transparent cylinder 22, but it is sufficient that at least a portion where the optical path of the sensor unit 21 is located can be cleaned. The tip of the brush 25 is in contact with the outer surface of the transparent cylinder 22. In FIG. 1 and FIG. 2, the brush 25 is provided at a position that does not block the optical path of the sensor unit 21 by being provided on the side of the transparent cylinder 22.

  In the optical sensor 20 configured as described above, the transparent cylinder 22 is rotated by rotating any one of the transparent cylinder rotating members 23 and 24 with a drive motor or the like. For example, in FIG. 1, when the transparent cylindrical rotating member 23 is rotated in the arrow C direction, the transparent cylinder 22 rotates in the arrow D direction, and the transparent cylindrical rotating member 24 rotates in the arrow B direction. Then, the part located on the optical path of the sensor part 21 of the transparent cylinder 22 is moved, and the brush 25 can remove dust and the like adhering to the outer surface of the part and clean it. Further, by rotating the transparent cylinder 22 one or more times, the outer surface of the portion of the transparent cylinder 22 with which the brush 25 is in contact (the portion located on the optical path of the sensor unit 21) is cleaned over the entire circumference.

  Next, the main part of the image forming apparatus having the optical sensor 20 configured as described above will be described with reference to FIG. The image forming apparatus includes a drum-shaped photosensitive member 1 as an image forming device, a cleaning device 2 that scrapes off toner remaining on the surface after transfer to the outer periphery of the photosensitive member 1, and a charging device that charges the surface of the photosensitive member 1. 3 and a developing device 4 for developing the charged photoreceptor 1 with toner.

  The photoreceptor 1 is a drum-shaped photoreceptor 1Y, 1C, or the like that forms toner images of four colors, for example, yellow (Y), cyan (C), magenta (M), and black (K) according to image information. 1M and 1K are provided.

  The photoconductor 1 is formed by providing an organic semiconductor layer, which is a photoconductive material, on a cylindrical surface of aluminum having a diameter of about 30 to 100 mm. Only is in contact with the surface 5 a of the intermediate transfer belt 5.

  The intermediate transfer belt 5 is stretched between rotating rollers 6 and 7 that rotate in the counterclockwise direction and rotates in the direction of arrow A, and a primary transfer device 8 is connected to each of the photoreceptors 1Y and 1Y on the back surface 5b side. 1C, 1M, 1K and the intermediate transfer belt 5 are disposed in the vicinity of the nip portion. The intermediate transfer belt 5 is an endless belt having a base film thickness of 50 to 600 μm as a base, and has a resistance value that enables transfer of toner from the photoreceptor 1.

  On the rotating roller 7 side of the intermediate transfer belt 5, the image transferred from the photosensitive member 1 to the intermediate transfer belt 5 by the primary transfer device 8 is transferred from the registration roller 10 to a recording medium supplied in time. A roller 11 is provided.

  In addition to the above-described components, the image forming apparatus includes a scanner unit that photoelectrically converts reflected light from an exposed document, a writing unit that projects laser light emitted from a light source onto the photosensitive member 1, and a recording medium Although not shown, the sheet feeding device for supplying the sheet and the discharging device for discharging the sheet on which the image is formed are configured as well-known copying machines and printers.

  The optical sensor 20 is provided so as to face the surface 5a of the intermediate transfer belt 5 as shown in FIG. In FIG. 3, it is provided at the lower part of the intermediate transfer belt 5, but the position is not limited to this and may be a position where an image pattern can be detected.

  According to the present embodiment, the sensor unit 21 that detects the image pattern is accommodated and covered in the transparent cylinder 22, thereby preventing adhesion of toner, floating dust, and the like to the sensor unit 21. Further, since the adhering matter adhering to the outer surface of the transparent cylinder 22 is removed by the brush 25 by being rotated by the transparent cylinder rotating members 23 and 24, the portion corresponding to the optical path of the sensor portion 21 of the transparent cylinder 22 is moved. Can be cleaned. Therefore, since the outer surface of the transparent cylinder 22 can be cleaned without blocking the optical path of the sensor unit 21, the cleaning operation can be performed during the detection operation of the image pattern formed on the intermediate transfer belt 5.

  In addition, by supporting the both ends of the transparent cylinder 22 rotatably with the transparent cylinder support members 26 and 27, it is possible to reduce the entry of toner, floating dust, and the like from both ends of the transparent cylinder 22.

  By the way, frictional charging occurs due to friction between the transparent cylinder 22 and the brush 25. The transparent cylinder 22 charged with this frictional charge may attract the toner on the intermediate transfer belt 5 and floating dust (for example, paper powder) around the transparent cylinder 22. In particular, when the toner on the intermediate transfer belt 5 is peeled off, the image is defective.

  In order to prevent the transparent cylinder 22 from adsorbing toner and floating dust, one of the following two methods may be used.

  The first method is to suppress the charging of the transparent cylinder 22, and for example, the transparent cylinder 22 and the brush 25 are subjected to an antistatic treatment with, for example, a titanium oxide coating, an antistatic fluororesin coating, or a conductive polymer. Like that. Furthermore, the brush 25 may be formed of a conductive member such as a resin fiber mixed with carbon fiber or carbon fine particles and grounded (grounded). In the case of using this method, it is desirable that the transparent cylinder 22 and the brush 25 are made of materials having the same charge train (charging series) (the same material may be used) and are in a state in which frictional charging is unlikely to occur in advance. Examples of the combination of materials close to the charged column include fluororesin and acrylic fiber, glass and polyamide resin. In the above-described combination, for example, the transparent cylinder 22 may be formed of fluororesin and the brush 25 may be formed of acrylic fiber. Conversely, the brush 25 is formed of fluororesin and the transparent cylinder 22 is formed of acrylic fiber. May be formed. The same applies to the combination of glass and polyamide resin. That is, the transparent cylinder 22 and the brush 25 can be made less likely to be charged by friction by selecting and forming a combination of materials whose charging series is close to the above-described combination of materials.

  The second method is a method in which the toner is positively charged while matching the polarity of the toner on the transparent cylinder 22 and the intermediate transfer belt 5, and focuses on preventing the toner on the intermediate transfer belt 5 from being peeled off. . In order to realize this method, in contrast to the first method, the transparent cylinder 22 and the brush 25 are selected from a combination of materials separated from each other in the charged row. Examples of combinations of materials that are separated from the charged column include fluororesin and polyamide resin, fluororesin and glass, and the like. In the above-described combination, for example, the transparent cylinder 22 may be formed of fluororesin and the brush 25 may be formed of polyamide resin. Conversely, the brush 25 is formed of fluororesin and the transparent cylinder 22 is formed of polyamide resin. May be formed. The same applies to the combination of fluororesin and glass. That is, the transparent cylinder 22 and the brush 25 can be easily charged by friction by selecting and forming a combination of materials that are separated from each other by a charge series that is approximately equal to the combination of the materials described above. In the case of this method, since the transparent cylinder 22 is positively charged, floating dust around the transparent cylinder 22 is easily adsorbed, and is strongly attached and difficult to remove with the brush 25. It is desirable to use in an environment where there is little floating dust.

(Second Embodiment)
Next, an optical sensor 20 according to a second embodiment of the present invention will be described with reference to FIGS. Note that the same parts as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted. FIG. 4 is a side view of the optical sensor according to the second embodiment of the present invention. FIG. 5 is a side view of another example of the optical sensor according to the second embodiment of the present invention. FIG. 6 is a side view of another example of the optical sensor according to the second embodiment of the present invention.

  As shown in FIGS. 4 and 5, the present embodiment is characterized in that toner, floating dust, or the like is blown out or sucked by using an airflow generating unit that generates an airflow instead of a brush as a cleaning unit. .

  FIG. 4 shows an example in which toner, floating dust, and the like on the outer surface of the transparent cylinder 22 are blown away by an air flow. In FIG. 4, similarly to the brush 25, the blowout nozzle 29 as an airflow generating means is provided at a position where the optical path of the sensor unit 21 is not blocked by being provided on the side of the transparent cylinder 22. Then, an air stream is blown from the blowing nozzle 29 onto the outer surface of the transparent cylinder 22 to blow off toner, floating dust, and the like.

  On the other hand, FIG. 5 shows an example in which toner, floating dust, and the like on the outer surface of the transparent cylinder 22 are sucked by an air flow. In FIG. 5, the suction nozzle 30 as the airflow generation means is provided at a position where the optical path of the sensor unit 21 is not blocked by being provided on the side of the transparent cylinder 22, similarly to the brush 25. Then, the suction nozzle 30 sucks in airflow near the outer surface of the transparent cylinder 22 to suck in toner, floating dust, and the like.

  Furthermore, as shown in FIG. 6, the cleaning member and the rotating member can be integrated by disposing the duct 31 below the transparent cylinder 22 (a position that does not block the optical path of the sensor unit 21).

  A portion of the duct 31 corresponding to the lower portion of the transparent cylinder 22 is opened so that the airflow strikes the transparent cylinder 22, and the airflow can be generated from one side of the duct 31 to the other as shown in FIG. Therefore, the transparent cylinder can be rotated in the direction of the arrow D by the air current, and at the same time, the air current strikes the outer surface of the transparent cylinder 22 so that it can be removed from the other side of the duct 31 by being removed from the toner and floating dust.

  According to the present embodiment, as the cleaning means, the nozzles 29, 30 and the duct 31 which are airflow generating members that generate an airflow on the surface of the transparent cylinder 22 are provided. Blowing away or sucking off toner or floating dust. Further, when the cleaning means is constituted by the brush 25, frictional charging is caused by the brush 25, and the transparent cylinder 22 is likely to adsorb floating dust. When the cleaning means is configured, frictional charging does not occur.

  Further, when the cleaning means is constituted by an air flow as in the second embodiment, in order to reduce the frictional resistance between the transparent cylinder 22 and the transparent cylinder support members 26 and 27 and smooth the rotation, the transparent cylinder It is desirable to insert a bearing such as a ball bearing or a sliding bearing between the cylindrical member 22 and the transparent cylindrical support members 26 and 27. Of course, a bearing may be used in the first embodiment.

  In the first and second embodiments, the rotating member is disposed in the lower portion and the cleaning member is disposed in the side portion. However, the present invention is not limited thereto, and any position that does not block the optical path of the sensor unit 21 may be used.

  In addition to the configurations shown in the first and second embodiments, the rotating member directly rotates from the rotating shaft of the transparent cylinder 22 or a driving force is transmitted to the end of the transparent cylinder 22 with a gear or the like. Various configurations such as a configuration can be adopted.

(Third embodiment)
Next, an optical sensor 20 according to a third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first and second embodiments described above are denoted by the same reference numerals and description thereof is omitted. FIG. 7 is a side view of an optical sensor according to the third embodiment of the present invention. FIG. 8 is a flowchart showing a control operation of the optical sensor shown in FIG.

  In the present embodiment, the configuration of the optical sensor 20 may be any of the first and second embodiments, but the control of the cleaning operation of the optical sensor 20 is different. FIG. 8 clearly shows the drive motor 32 for rotating the transparent cylindrical rotating member 23 and the control means 33 for controlling the drive motor 32 based on the output from the sensor unit 21 in the configuration shown in FIG. . The control means 33 can be constituted by a microcomputer provided with a memory such as a CPU, a ROM, and a RAM.

  In the first and second embodiments, the sensor unit 21 is covered with the transparent cylinder 22, and the cleaning means such as the transparent cylinder rotating members 23 and 24 and the brush 25 are arranged at positions that do not block the optical path of the sensor unit 21. The cleaning operation can be performed at an arbitrary timing such as during the image pattern detection operation. In the present embodiment, in addition to that, by measuring sensor outputs at all rotational positions (one round of the outer surface) of the transparent cylinder 22 in advance, the degree of dirt is grasped and cleaned in advance. It is a thing. The detailed operation will be described with reference to the flowchart of FIG. The flowchart shown in FIG. 8 is executed by the control means 33.

  First, in step S11, the intermediate transfer belt 5 is stopped and the operation of forming an image pattern on the intermediate transfer belt 5 is stopped, and the process proceeds to step S12.

  Next, in step S12, the drive motor 32 is operated to measure the output signal levels of the sensor units 21 at all rotational positions of the transparent cylinder 22, and the process proceeds to step S13. The measured output of the sensor unit 21 is recorded in the control means 33. That is, the control unit 33 functions as a first recording unit that records the output of the sensor unit at all the rotational positions of the cylindrical member.

  Next, in step S13, the drive motor 32 is operated to clean the outer surface of the transparent cylinder 22, and the process proceeds to step S14.

  Next, in step S14, it is determined whether or not the amount of dirt is equal to or less than a certain amount. When the amount is less than or equal to a certain amount (in the case of Y), the process ends. Returns to step S13 to perform cleaning. The determination as to whether or not the amount has reached a certain amount or less may be made based on whether or not the output signal from the sensor unit 21 is at a predetermined level or higher. If the output signal level of the sensor unit 21 is high, the transparent cylinder 22 is less contaminated, and strong light is detected by the light receiving unit. Therefore, the degree of contamination is determined by the output signal level of the sensor unit 21. It is possible. That is, the control unit 33 rotates the cylindrical member with the rotating member, and the output of the sensor unit recorded in the first recording unit exceeds the predetermined value determined in advance at all the rotational positions. It functions as a first cleaning control means for performing removal.

  That is, in the flowchart of FIG. 8, the cleaning is performed until the contamination of the transparent cylinder 22 becomes a certain amount or less before the image pattern detection.

  According to this embodiment, the control means 33 operates the drive motor 32 to rotate the transparent cylinder 22 by the transparent cylinder rotating members 23, 24, and all the output signal levels of the sensor unit 21 recorded in the control means 33 are all. Since the cleaning is performed by the brush 25 until a predetermined value is exceeded at the rotational position, the cleaning can be performed until the contamination of the transparent cylinder 22 becomes a predetermined amount or less before the image pattern is detected.

(Fourth embodiment)
Next, an optical sensor 20 according to a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first to third embodiments described above are denoted by the same reference numerals and description thereof is omitted. FIG. 9 is a flowchart showing the control operation of the optical sensor according to the fourth embodiment of the present invention.

  In the present embodiment, the transparent cylinder 22 is rotated by a predetermined number of rotations to perform a cleaning operation, and then sensor outputs at all rotational positions of the transparent cylinder 22 are measured, and based on the output signal level of the sensor unit 21. It is determined whether or not error notification is performed. In this way, useless cleaning operation can be prevented and an abnormality can be notified to the user or the like. The detailed operation of this embodiment will be described with reference to the flowchart of FIG. The flowchart shown in FIG. 9 is executed by the control means 33.

  First, in step S21, the drive motor 32 is operated to rotate the transparent cylinder 22 by a predetermined number of rotations to clean the transparent cylinder 22, and the process proceeds to step S22. That is, the control means 33 functions as a second cleaning control means for rotating the cylindrical member by the rotating member and removing the deposits by the cleaning member by a predetermined number of rotations.

  Next, in step S22, the drive motor 32 is operated to measure the output signal level of the sensor unit 21 for one round of the transparent cylinder 22, and the process proceeds to step S23. The output of the sensor unit 21 measured in this step is recorded in the control means 33.

  Next, in step S23, it is determined whether or not all output signal levels of the sensor unit 21 measured in step S22 are equal to or higher than a predetermined value. As a result of the determination, if it is equal to or greater than a predetermined value, image pattern image formation is started as normal termination, and if any output signal level is less than the predetermined value, error output is performed as abnormal termination. The error output is, for example, stopping the image forming operation of the image forming apparatus or making an announcement such as replacement of parts of the optical sensor 20 (transparent cylinder 22) to the user. That is, after the removal of the deposits by the cleaning control means is completed, the control means 33 rotates the cylindrical member once again by the rotating member, and all the outputs of the sensor units at the rotational positions of all the cylindrical members are predetermined values. If the value of the output of the sensor part for one round does not exceed a predetermined value, it functions as a detection control means that outputs information indicating an error. ing.

  That is, in the flowchart of FIG. 9, when the optical sensor 20 (transparent cylinder 22) is severely soiled or scratched, the user can be notified of an error.

  According to this embodiment, the control means 33 operates the drive motor 32 to rotate the transparent cylinder 22 by the transparent cylinder rotating members 23 and 24 a predetermined number of times, and after the cleaning is completed, the sensor unit 21 of all the rotation positions of the transparent cylinder 22. Measure the output signal level. When all of the measured values are equal to or greater than a predetermined value, image formation of the image pattern is started as normal termination, and when even one of the measured values is less than the predetermined value, error display is performed as abnormal termination. Therefore, when the optical sensor 20 is severely soiled or scratched, an error can be notified to the user.

  As another form of the control operation as in the third and fourth embodiments, all the rotational positions of the transparent cylinder 22 are rotated by rotating the transparent cylinder 22 once (periods may be arbitrary) from the time of shipment. The output signal level of the sensor unit 21 is measured and recorded. Then, based on the recorded output signal level, sensitivity reduction due to scratches or clouding of the transparent cylinder 22 is calculated as a correction value, and the output signal level of the sensor unit 21 at the time of image pattern detection is corrected. Also good. That is, the control means 33 is a rotation control means, a second recording means, and a sensitivity correction value calculation means. You may make it function as a correction | amendment means.

  In the above-described embodiment, the optical sensor used in the image forming apparatus has been described. However, the present invention is applied to any optical sensor that detects an object to be detected and has a possibility of dust adhering to the periphery. can do.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention.

1 Photoconductor (image forming device)
5 Intermediate transfer belt (image carrier)
20 Optical sensor 21 Sensor part 22 Transparent cylinder (cylindrical member)
23, 24 Transparent cylindrical rotating member (Rotating member)
25 Brush (cleaning member, brush member)
26, 27 Transparent cylindrical support member (support member)
29 Nozzles (cleaning members, airflow generating members)
30 nozzles (cleaning members, airflow generating members)
31 Duct (Rotating member, Cleaning member, Airflow generating member)
33 Control means (first recording means, first cleaning control means, second cleaning control means, detection control means, rotation control means, second recording means, sensitivity correction value calculation means, correction means)

Japanese Patent No. 431547

Claims (15)

In an optical sensor having a sensor unit that is fixed so as to face the object to be detected, and detects the object by irradiating light.
A cylindrical member that is formed of a material through which the curved surface intersects the optical path of the light emitted from the sensor unit and that accommodates the sensor unit;
A rotating member that rotates the cylindrical member;
A cleaning member that is provided at a position that does not block the optical path, and that removes adhering matter adhering to the outer surface of the cylindrical member;
An optical sensor comprising:   The optical sensor according to claim 1, wherein the cleaning member includes a brush member.   The optical sensor according to claim 1, wherein the surface of the cylindrical member is subjected to a treatment for preventing reflection of light.   The optical sensor according to claim 2, wherein the cylindrical member and the brush member are subjected to antistatic treatment.   The optical sensor according to claim 2, wherein the brush member is formed of a conductive member and is grounded.   The said cylindrical member and the said brush member are formed with the combination in any one of a fluororesin and an acrylic fiber, or glass and a polyamide resin, The Claim 1 thru | or 5 characterized by the above-mentioned. Optical sensor.   4. The optical sensor according to claim 2, wherein the cylindrical member and the brush member are formed of any combination of fluororesin and polyamide resin, or fluororesin and glass.   The optical sensor according to claim 1, wherein the cleaning member includes an airflow generation member that generates an airflow on an outer surface of the cylindrical member.   The optical sensor according to claim 8, wherein the rotating member and the cleaning member are integrally formed. A support member for supporting the cylindrical member so as to be rotatably positioned at a predetermined position;
The optical sensor according to claim 1, wherein a bearing is provided between the cylindrical member and the support member. First recording means for recording the output of the sensor unit at all rotational positions of the cylindrical member;
The cylindrical member is rotated by the rotating member, and the output of the sensor unit recorded in the first recording means exceeds the predetermined value determined in advance at all the rotational positions, and the deposit by the cleaning member is removed. First cleaning control means for performing removal;
The optical sensor according to claim 1, further comprising: A second cleaning control means for rotating the cylindrical member by the rotating member and removing the deposit by the cleaning member by a predetermined number of rotations;
After the removal of the deposits by the second cleaning control means, the cylindrical member is again rotated once by the rotating member, and all the outputs of the sensor unit at all rotational positions of the cylindrical member are predetermined. Detection control means for detecting the detected object when a predetermined value is exceeded;
The optical sensor according to claim 1, further comprising:   The optical sensor according to claim 12, wherein the detection control unit outputs information indicating an error when there is a value that does not exceed a predetermined value among outputs of the sensor unit for one round. . Rotation control means for rotating the cylindrical member once by the rotating member at an arbitrary interval;
Second recording means for recording the output of the sensor unit at all rotational positions of the cylindrical member when the rotation control means rotates the cylindrical member;
Sensitivity correction value calculating means for calculating a sensitivity correction value of the sensor unit based on the output of the sensor unit recorded in the second recording unit;
Correction means for correcting the sensor unit output at the time of detection of the detected object based on the sensitivity correction value calculated by the sensitivity correction value calculation means;
The optical sensor according to claim 1, comprising: An image forming apparatus comprising: an image forming apparatus that forms an image pattern on an image carrier; and an optical sensor that detects the image pattern formed on the image carrier by irradiating the image carrier with light.
An image forming apparatus comprising the optical sensor according to claim 1, wherein the optical sensor is provided to face the image carrier.

Images