JP2014153374A - Image forming apparatus, sensing method, program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of suppressing a reduction in image quality.SOLUTION: A printer control device acquires output signals of a reflective optical sensor 2245 obtained when a light shielding member 100a is in a "closed state" as pre-operation information before the operation of a color printer is started, and calculates a light intensity correction coefficient from the output signals of the reflective optical sensor obtained when the light shielding member is in a "closed state" and the pre-operation information, in surface state check processing performed after the operation of the color printer is started. The printer control device then corrects an influence of a change in temperature and a change over time of the reflective optical sensor with respect to output signals of the reflective optical sensor obtained when the light shielding member is in an "open state" by using the light intensity correction coefficient.

Description

  The present invention relates to an image forming apparatus, a sensing method, a program, and a recording medium. More specifically, the present invention relates to an image forming apparatus having a moving body, a sensing method using a sensor that receives light reflected by an object, and an object. The present invention relates to a program used in an apparatus including a sensor that receives reflected light, and a computer-readable recording medium on which the program is recorded.

  An image forming apparatus generally includes a photosensitive drum and a charging device, an exposure device, a developing device, and the like disposed around the photosensitive drum. The surface of the photosensitive drum is uniformly charged by a charging device, and the charged portion is exposed by laser light emitted from the exposure device. As a result, an electrostatic latent image is formed on the photosensitive drum, and the electrostatic latent image is developed by the developing device to become a toner image.

  The toner image on the photosensitive drum is transferred to the paper that has been transported by the transport belt. The sheet on which the toner image is transferred is peeled off from the conveyance belt and conveyed to the fixing device, where the toner is fixed and discharged.

  The fixing device has a fixing belt for heating and pressurizing the paper. For example, in an image forming apparatus that can use A4 size paper and A3 size paper, if fixing of A4 size paper is repeated in a state of longitudinal paper, the end of the A4 size paper on the surface of the fixing belt in the paper width direction passes. Vertical streak may occur at the position. This occurs when the surface of the fixing belt is roughened by burrs or paper dust at the paper edge.

  At this time, when A4 size paper is passed horizontally or A3 size paper is passed vertically, so-called glossy streaks appear on the image surface corresponding to the vertical streak and image quality deteriorates. Accordingly, an image forming apparatus that can detect the surface state of the fixing member has been devised (see, for example, Patent Document 1 and Patent Document 2).

  The demand for image quality in image forming apparatuses is increasing year by year. However, in the image forming apparatuses disclosed in Patent Document 1 and Patent Document 2, it is difficult to stably and accurately detect the surface state of the fixing member, and there is a possibility that the image quality may be deteriorated.

  The present invention provides a sensor having a light emitting unit and a light receiving unit that emits light toward a moving body, and outputs the sensor by turning on the light emitting unit when the moving body is in a first usage state with respect to usage time. Obtained as a first output value, and when the moving body is in a second usage situation in which the usage time is longer than the first usage situation, the light emitting unit is turned on to obtain the sensor output as a second output value Then, based on the first output value and the second output value, the light emitted from the sensor and reflected by the movable body is incident on the sensor when the movable body is in the second usage state. And a processing device that corrects the output of the sensor at the time.

  According to the image forming apparatus of the present invention, it is possible to suppress a decrease in image quality.

1 is a diagram for describing a schematic configuration of a color printer according to an embodiment of the present invention. FIG. It is a figure for demonstrating a fixing device. FIG. 6 is a diagram for explaining a site where a flaw occurs in the fixing belt. It is a figure for demonstrating the arrangement position of a reflection type optical sensor. It is FIG. (1) for demonstrating a reflection type optical sensor. It is FIG. (2) for demonstrating a reflection type optical sensor. It is FIG. (3) for demonstrating a reflection type optical sensor. It is FIG. (4) for demonstrating a reflection type optical sensor. It is FIG. (5) for demonstrating a reflection type optical sensor. FIGS. 10A to 10D are diagrams for explaining light spots formed on the surface of the fixing belt, respectively. It is a figure for demonstrating the arrangement order of the light emission part regarding the y-axis direction in the group p, and the arrangement order of the formation position of a light spot. It is a figure for demonstrating a light irradiation position. It is a figure for demonstrating the detection range of a reflection type optical sensor. It is FIG. (1) for demonstrating the optical path of reflected light. It is FIG. (2) for demonstrating the optical path of reflected light. FIG. 16A and FIG. 16B are diagrams for explaining the light shielding mechanism. It is a figure for demonstrating the output value of each light-receiving part when a light-shielding member is made into a "closed state" and the light emission part E41, the light emission part E42, the light emission part E43, and the light emission part E44 are lighted separately. It is a figure for demonstrating the reason the output value of a light-receiving part does not become 0 when a light shielding member is a "closed state." It is a figure for demonstrating the output value of each light-receiving part when subtracting the light-receiving part output when a light shielding member is a "closed state" from the light-receiving part output when a light-shielding member is an "open state." Before the start of operation of the color printer 2000, 28 light-receiving units (D1 to D28) when the light-shielding member 100a is in the “closed state” and the 20 light-emitting units from the groups 2 to 6 are individually turned on. It is a figure for demonstrating the output value of (). It is a figure for demonstrating the result (PV value) which subtracted the minimum value from the maximum value of the light-receiving part output value for every light emission part in FIG. 28 light-receiving sections at the same timing after the start of operation of the color printer 2000 when the light-shielding member 100a is in the “closed state” and the 20 light-emitting sections from the groups 2 to 6 are individually lit. It is a figure for demonstrating the output value of (D1-D28). It is a figure for demonstrating the result (PV value) which subtracted the minimum value from the maximum value of the light-receiving part output value for every light emission part in FIG. It is a figure for demonstrating the light quantity correction coefficient computed from FIG. 21 and FIG. 28 light-receiving units at the same timing after the start of operation of the color printer 2000, when the light-shielding member 100a is in the “open state” and the 20 light-emitting units from group 2 to group 6 are individually lit. It is a figure for demonstrating the output value of (D1-D28). It is a figure for demonstrating the sum of the light-receiving part output value for every light emission part in FIG. It is a figure for demonstrating the result of having divided the sum of the light-receiving part output value for every light emission part in FIG. 26 by the light quantity correction coefficient. It is a flowchart for demonstrating the pre-operation information acquisition process. It is a flowchart (the 1) for demonstrating a surface state check process. It is a flowchart (the 2) for demonstrating a surface state check process. It is a flowchart (the 3) for demonstrating a surface state check process. It is a figure for demonstrating the relationship between a 5th detection value and a lighting light emission part. It is a figure for demonstrating the relationship between a 5th detection value and a light irradiation position. It is a figure for demonstrating the method of calculating | requiring a differential value. It is a figure for demonstrating the relationship between a differential value and a light irradiation position. It is a figure for demonstrating a zero cross position. It is FIG. (1) for demonstrating the method of calculating | requiring the depth parameter of a damage | wound. It is FIG. (2) for demonstrating the method of calculating | requiring the depth parameter of a damage | wound. It is a figure for demonstrating the method of calculating | requiring the width | variety of a flaw. It is a flowchart for demonstrating the modification of the pre-operation information acquisition process. It is a flowchart for demonstrating the modification 1 of a surface state check process. It is a flowchart for demonstrating the modification 2 of a surface state check process. FIG. 43A and FIG. 43B are diagrams for explaining a first modification example of the light shielding mechanism. 44 (A) and 44 (B) are diagrams for explaining a second modification example of the light shielding mechanism. It is a figure for demonstrating the modification of the attachment attitude | position of a reflection type optical sensor. It is a figure for demonstrating the case where two reflection type optical sensors are provided.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a color printer 2000 according to an embodiment.

  The color printer 2000 is a tandem multi-color printer that forms a full-color image by superimposing four colors (black, cyan, magenta, and yellow), and includes an optical scanning device 2010, four photosensitive drums (2030a, 2030b, 2030c, 2030d), four cleaning units (2031a, 2031b, 2031c, 2031d), four charging devices (2032a, 2032b, 2032c, 2032d), four developing rollers (2033a, 2033b, 2033c, 2033d), 4 Transfer rollers (2034a, 2034b, 2034c, 2034d), intermediate transfer belt 2040, secondary transfer roller 2042, fixing device 2050, paper feed roller 2054, paper discharge roller 2058, paper feed tray 2060, paper discharge tray 2070 Communication control device 2080, the reflection type optical sensor 2245, blocking mechanism 100, an operation panel (not shown) and a printer control unit 2090 for centrally controlling the above units.

  The communication control device 2080 controls bidirectional communication with a host device (for example, a personal computer) via a network or the like.

  The printer control device 2090 converts a CPU, a program written in a code decipherable by the CPU, and various data used when executing the program, an amplifier circuit, and an analog signal into a digital signal. An A / D conversion circuit is provided. Then, the printer control device 2090 notifies the optical scanning device 2010 of multi-color image information (black image information, cyan image information, magenta image information, yellow image information) received from the host device via the communication control device 2080. To do.

  The operation panel has a plurality of keys for the operator to make various settings and a display for displaying various information.

  The photosensitive drum 2030a, the charging device 2032a, the developing roller 2033a, the transfer roller 2034a, and the cleaning unit 2031a are used as a set and form an image forming station (hereinafter also referred to as “K station” for convenience) that forms a black image. Configure.

  The photosensitive drum 2030b, the charging device 2032b, the developing roller 2033b, the transfer roller 2034b, and the cleaning unit 2031b are used as a set, and form an image forming station (hereinafter also referred to as “C station” for convenience) that forms a cyan image. Configure.

  The photosensitive drum 2030c, the charging device 2032c, the developing roller 2033c, the transfer roller 2034c, and the cleaning unit 2031c are used as a set, and form an image forming station (hereinafter also referred to as “M station” for convenience) that forms a magenta image. Configure.

  The photosensitive drum 2030d, the charging device 2032d, the developing roller 2033d, the transfer roller 2034d, and the cleaning unit 2031d are used as a set and form an image forming station (hereinafter also referred to as “Y station” for convenience) that forms a yellow image. Configure.

  Each photosensitive drum has a photosensitive layer formed on the surface thereof. Here, the surface of each photosensitive drum is a surface to be scanned. Each photosensitive drum is rotated in the direction of the arrow in the plane of FIG. 1 by a rotation mechanism (not shown).

  Each charging device uniformly charges the surface of the corresponding photosensitive drum.

  The optical scanning device 2010 scans the surface of the corresponding charged photosensitive drum with light modulated for each color based on multicolor image information from the printer control device 2090. Thereby, a latent image corresponding to the image information is formed on the surface of each photosensitive drum. The latent image formed here moves in the direction of the corresponding developing roller as the photosensitive drum rotates.

  As each developing roller rotates, toner from a corresponding toner cartridge (not shown) is thinly and uniformly applied to the surface thereof. Then, when the toner on the surface of each developing roller comes into contact with the surface of the corresponding photosensitive drum, the toner moves only to a portion irradiated with light on the surface and adheres to the surface. In other words, each developing roller causes toner to adhere to the latent image formed on the surface of the corresponding photosensitive drum to make it visible. Here, the toner-attached image (toner image) moves in the direction of the intermediate transfer belt 2040 as the photosensitive drum rotates.

  Each transfer roller transfers the toner image to the intermediate transfer belt 2040.

  The yellow, magenta, cyan, and black toner images are sequentially transferred onto the intermediate transfer belt 2040 at a predetermined timing, and are superimposed to form a color image.

  Recording paper is stored in the paper feed tray 2060. A paper feed roller 2054 is disposed in the vicinity of the paper feed tray 2060. The paper feed roller 2054 takes out the recording paper one by one from the paper feed tray 2060. The recording sheet is sent out toward the gap between the intermediate transfer belt 2040 and the secondary transfer roller 2042 at a predetermined timing. As a result, the toner image on the intermediate transfer belt 2040 is transferred to the recording paper. The recording paper on which the toner image is transferred is sent to the fixing device 2050.

  In the fixing device 2050, heat and pressure are applied to the recording paper, thereby fixing the toner on the recording paper. The recording paper on which the toner is fixed is sent to the paper discharge tray 2070 via the paper discharge roller 2058 and is sequentially stacked on the paper discharge tray 2070.

  Each cleaning unit removes toner (residual toner) remaining on the surface of the corresponding photosensitive drum. The surface of the photosensitive drum from which the residual toner has been removed returns to the position facing the corresponding charging device again.

  The reflective optical sensor 2245 is disposed in the vicinity of the fixing device 2050. Details of the reflective optical sensor 2245 will be described later.

  As shown in FIG. 2 as an example, the fixing device 2050 includes a pressure roller 501, a fixing belt 502, a fixing roller 503, a heating roller 504, a tension roller 505, a separation claw 506, a temperature sensor (not shown), and the like. Have.

  Here, in the xyz three-dimensional orthogonal coordinate system, a direction orthogonal to the paper surface of the recording paper conveyed to the fixing device 2050 is defined as a z-axis direction. The conveyance direction of the recording paper is the + x direction.

  The pressure roller 501 is formed by coating a metal core such as aluminum or iron with an elastic member such as silicone rubber and coating the surface with a fluororesin.

  The fixing belt 502 is made of nickel, polyimide, or the like as a base material and has a surface coated with a fluororesin. An elastic member such as silicone rubber may be added between the base material and the fluororesin.

  The fixing belt 502 is wound around a fixing roller 503 and a heating roller 504, and is maintained at an appropriate tension by a tension roller 505.

  The fixing roller 503 is formed by coating a metal core such as aluminum or iron with silicone rubber.

  The heating roller 504 includes an aluminum or iron hollow roller and a heat source such as a halogen heater provided inside the hollow roller.

  The tension roller 505 is a metal core such as aluminum or iron covered with silicone rubber.

  A plurality of separation claws 506 are provided along a direction parallel to the rotation axis of the fixing roller 503 (here, the y-axis direction). The leading end of each separation claw 506 is in contact with the surface of the fixing roller 503.

  The temperature sensor detects the temperature of the fixing belt 502 on the heating roller 504 in a non-contact manner. Note that a contact-type temperature sensor may be used as the temperature sensor.

  In the fixing device 2050, when the recording paper enters the nip portion formed by the fixing roller 503 and the pressure roller 501, a predetermined pressure and heat are applied to the recording paper in the nip portion, and the toner image on the recording paper. Is established.

  When the fixing of the A4 size recording paper is repeated in the state of the longitudinal paper in the fixing device 2050, a vertical streak is generated at a position where the end of the recording paper in the width direction passes on the surface of the fixing belt 502. (See FIG. 3). This occurs when the surface of the fixing belt 502 is roughened by burrs or paper dust at the end of the recording paper. A fixing belt having a high surface hardness is particularly easily damaged.

  At this time, if the A4 recording paper is passed horizontally or the A3 recording paper is passed vertically, so-called glossy streaks appear on the image surface corresponding to the scratches, and the image quality deteriorates.

  Therefore, a reflective optical sensor 2245 is disposed in the vicinity of the fixing device 2050 in order to detect the position of the scratch and the state of the scratch (scratch depth, scratch width) on the fixing belt 502.

  The reflective optical sensor 2245 is disposed on the + z side of the fixing device 2050. With respect to the y-axis direction, the reflective optical sensor 2245 is disposed at a position facing one of the sites where the scratch occurs on the fixing belt 502 (hereinafter, abbreviated as “scratch site”). (See FIG. 4). In FIG. 4, the reflective optical sensor 2245 is arranged at a position facing the −y side wound occurrence part of the two wound occurrence parts, but reflected at a position facing the + y side wound occurrence part. A mold optical sensor 2245 may be arranged.

  The configuration of the reflective optical sensor 2245 will be described with reference to FIGS. 6 is a cross-sectional view taken along line AA of FIG. 5, FIG. 7 is a cross-sectional view taken along line BB of FIG. 5, and FIG. 8 is a cross-sectional view taken along line CC of FIG. FIG. 9 is a view when the lens member is removed from FIG.

  The reflective optical sensor 2245 has a quadrangular prism-shaped outer shape whose longitudinal direction is the y-axis direction, and includes 28 light emitting units, 7 illumination lenses (EL1 to EL7), and 1 light receiving lens DL, 28. Each light receiving section (D1 to D28), a substrate 45, a frame member 46, an opening member 47, and the like are provided. The seven illumination lenses and the single light receiving lens DL are all made of resin, and the lens member is a combination of them.

  The 28 light-emitting portions are divided into 7 groups (group 1 to group 7). The four light emitting units in each group are arranged close to each other in the y-axis direction. Then, the four light emitting portions of the set p (p = 1 to 7) are expressed as “light emitting portion Ep1”, “light emitting portion Ep2”, “light emitting portion Ep3”, and “light emitting portion Ep4” in the + y direction. To do. In addition, the distance between the pair is equal in the y-axis direction. Each light emitting unit is turned on and off by the printer control device 2090. Hereinafter, for convenience, the light emitting unit that is turned on is also referred to as a “lighting light emitting unit”.

  Seven illumination lenses are provided corresponding to the set. Each illumination lens guides light emitted from a corresponding set of light emitting portions toward the surface of the fixing belt 502 in a condensed manner. Hereinafter, the illumination lens corresponding to the set p is referred to as “illumination lens ELp”.

  In the set p, the light emitted from the light emitting unit Ep1 is collected by the illumination lens ELp to form a light spot Sp1 on the surface of the fixing belt 502 (see FIG. 10A). The light emitted from the light emitting portion Ep2 is collected by the illumination lens ELp to form a light spot Sp2 on the surface of the fixing belt 502 (see FIG. 10B). The light emitted from the light emitting part Ep3 is collected by the illumination lens ELp to form a light spot Sp3 on the surface of the fixing belt 502 (see FIG. 10C). The light emitted from the light emitting unit Ep4 is collected by the illumination lens ELp to form a light spot Sp4 on the surface of the fixing belt 502 (see FIG. 10D).

  Each light spot is formed at a different position on the surface of the fixing belt 502 with respect to the y-axis direction. Regarding the y-axis direction, the direction in which the four light emitting units are arranged is opposite to the direction in which the four light spots are arranged (see FIG. 11). Here, the formation pitch of the plurality of light spots in the y-axis direction is 1 mm. Note that a position where a light spot is formed on the surface of the fixing belt 502 in the y-axis direction is also referred to as a light irradiation position (see FIG. 12). Here, as an example, the position where the light spot S13 is formed is the origin (0 mm) of the light irradiation position.

  In the present embodiment, the position of the flaw and the flaw state (flaw depth, flaw width) on the fixing belt 502 are detected using 20 light emitting units of the groups 2 to 6. Therefore, as shown in FIG. 13 as an example, the formation position of the light spot S24 by the light emitted from the light emitting portion E24 of the set 2 and the formation position of the light spot S61 by the light emitted from the light emitting portion E61 of the set 6 Is a detection region in the y-axis direction (hereinafter also simply referred to as “detection region”). Here, 19 mm is the detection region.

  By the way, when A4 size recording paper is passed through the fixing belt 502 in the longitudinal direction, the position of the recording paper in the y-axis direction varies slightly. When a so-called “belt shift” occurs in the fixing belt 502, the relative position of the recording paper with respect to the y-axis direction with respect to the fixing belt 502 changes. Furthermore, the position in the y-axis direction may be intentionally changed for each recording sheet. Therefore, the end position of the recording paper in the y-axis direction also varies. The size (variation width) of this fluctuation region is 10 mm or less. Since the flaw occurrence site exists somewhere in the fluctuation area, the detection area of the reflective optical sensor 2245 needs to be set to be larger than the fluctuation width.

  In the present embodiment, the detection area of the reflective optical sensor 2245 is 19 mm, which is larger than the fluctuation range, so that it is possible to reliably detect the site where the scratch has occurred. Further, since the detection area of the reflective optical sensor 2245 is considerably larger than the fluctuation range, the arrangement position of the reflective optical sensor 2245 in the y-axis direction may be somewhat rough.

  The 28 light receiving parts are arranged at equal intervals along the y-axis direction (see FIG. 9). Here, the arrangement pitch of the 28 light receiving parts is 1 mm. Each light receiving unit outputs a signal (photoelectric conversion signal) having a level corresponding to the amount of received light to the printer control device 2090.

  The light receiving lens DL is a single cylindrical lens disposed on the + z side of the 28 light receiving portions, and has a positive optical power only in the x-axis direction (see FIGS. 7 and 8).

  The light reflected by the fixing belt 502 is collected only in the x-axis direction by the light receiving lens DL and enters the light receiving unit (see FIGS. 14 and 15).

  The frame member 46 is disposed between the substrate 45 and the lens member so that the distance between the substrate 45 and the lens member is a desired interval. Therefore, the 28 light emitting units and the 28 light receiving units are sealed in a space formed by the substrate 45, the lens member, and the frame member 46, thereby preventing contamination of the light emitting unit and the light receiving unit. Can do. The frame member 46 may be made of resin, and the frame member 46 may be molded integrally with the lens member.

  The opening member 47 is provided between the plurality of light emitting units and the plurality of illumination lenses, and prevents the light emitted from the light emitting units from entering the illumination lens corresponding to the adjacent set. Light other than the reflected light from the object is prevented from entering the light receiving unit. The opening member 47 may be made of resin, and the opening member 47 may be molded integrally with at least one of the lens member and the frame member 46. Here, the opening member 47 has seven openings (through holes) corresponding to the seven sets. The opening member 47 may be created by making a hole in a block-like member, or may be created by combining a plurality of plate-like members.

  The light shielding mechanism 100 is provided between the reflective optical sensor 2245 and the fixing belt 502. The light shielding mechanism 100 includes a light shielding member 100a and a driving device 100b. As shown in FIGS. 16A and 16B as an example, the light shielding member 100a can be moved in the x-axis direction by the driving device 100b. It is. Hereinafter, the time when the light shielding member 100a is in the position shown in FIG. 16A is also referred to as “closed state”, and the time when it is in the position shown in FIG. 16B is also referred to as “open state”. The driving device 100b is controlled by the printer control device 2090.

  The light shielding member 100a has an opaque engineering plastic having heat resistance against high temperatures as a main member, and a black low reflection member is attached to the surface on the −z side. Engineering plastics are commonly called engineering plastics. A super engineering plastic with particularly high heat resistance may be used for the light shielding member 100a.

  As the black low reflection member, there is a thin light absorption film or the like, and when the light shielding member 100a is in the “closed state”, the light emitted from the reflection type optical sensor 2245 is absorbed and is received by the light receiving portion of the reflection type optical sensor 2245. It has a function to prevent light from being received. If the engineering plastic used for the light shielding member 100a has a low reflection function, the black low reflection member is unnecessary.

  Further, the light shielding member 100a is set so that the length in the y-axis direction is the same as or slightly longer than the width of the fixing belt 502 (length in the y-axis direction), and heat from the fixing belt 502 is reflected. Also has a heat shielding function to prevent direct transmission to the mold optical sensor 2245

  When the light shielding member 100 a is in the “open state”, the light emitted from the reflective optical sensor 2245 is irradiated on the fixing belt 502, and the light reflected on the surface of the fixing belt 502 is incident on the reflective optical sensor 2245. On the other hand, when the light shielding member 100a is in the “closed state”, the light emitted from the reflective optical sensor 2245 is absorbed by the light shielding member 100a and does not enter the reflective optical sensor 2245.

  FIG. 17 shows the light-emitting part E41, the light-emitting part E42, the light-emitting part E43, and the light-emitting part E44 when the light-shielding member 100a is in the “closed state”, that is, when there is no object that reflects the light emitted from the reflective optical sensor 2245. The relative output value of each light-receiving unit when is individually turned on is shown. If there is no object that reflects light, the output value of each light receiving unit should be zero if it is originally, but the output values of the light receiving unit D14 and the light receiving unit D15 are set as shown in FIG. A peak output distribution is obtained. The inventors investigated the cause of the output distribution in detail. As shown in FIG. 18, a part of the light emitted from the light emitting part is reflected by the front surface of the opening member 47 and received by the light receiving part. I found out that it was because it was done.

  In FIG. 19, light is emitted when the light shielding member 100a is in the “open state”, that is, the light emitted from the reflective optical sensor 2245 is reflected by the fixing belt 502 and the reflected light is incident on the reflective optical sensor 2245. From the output values of the respective light receiving parts when the part E41, the light emitting part E42, the light emitting part E43, and the light emitting part E44 are individually turned on, the light shielding member 100a is “closed”, that is, emitted from the reflective optical sensor 2245. The result of subtracting the output value of each light-receiving unit when the light-emitting unit E41, the light-emitting unit E42, the light-emitting unit E43, and the light-emitting unit E44 are individually turned on with no object reflecting light is shown. Thereby, it is possible to obtain the output value of each light receiving unit when only the light reflected by the fixing belt 502 is received.

  When attention is paid to the peak of the output value in FIG. 19, when the lighting light emitting part changes as E44 → E43 → E42 → E41, the light receiving part where the output value reaches the peak is D10 → D15 → D16 → D18. The number is shifted from the smallest to the largest. This corresponds to the fact that the position of the light spot on the surface of the fixing belt 502 changes in the + y direction when the lighting light emitting unit changes in the -y direction.

  By the way, when one light emitting part is turned on when the light shielding member 100a is in the “closed state”, the light emitted from the light emitting part is directly reflected by the opening member 47 and received by the light receiving part. If the shape of the opening member 47 when viewed from the light emitting unit is the same, it is considered that a signal proportional to the amount of light emitted from the light emitting unit is output from the reflective optical sensor 2245. Here, since the size of the opening portion corresponding to one set in the opening member 47 is sufficiently larger than the size of the arrangement region of the four light emitting portions of the one set, it can be seen from any light emitting portion. It can be considered that the shape of the opening member 47 is the same. Therefore, when the light shielding member 100a is set to the “closed state” and the plurality of light emitting units are individually turned on to obtain the output of the reflective optical sensor 2245 for each light emitting unit, the relationship between the light emitting unit and the output of the reflective optical sensor 2245 is obtained. Is considered to correspond to the variation in the amount of light emitted by the plurality of light emitting units at that time.

  Also, FIG. 20 shows 28 units before the start of operation of the color printer 2000 and when the light-shielding member 100a is in the “closed state” and the 20 light emitting units from the group 2 to the group 6 are individually turned on. The output of the light receiving unit is shown.

  The term “before the start of operation of the color printer 2000” means a point in time before the color printer 2000 is used by the user, and specifically refers to the time when the color printer 2000 is manufactured or shipped. Alternatively, it may be sold to the user and installed in the user's usage environment (when it arrives). At these times, the color printer 2000 is generally at room temperature (20 to 25 °). Since the fixing device 2050 is not operated, the temperature in the vicinity of the reflective optical sensor 2245, that is, in each light emitting unit is also in the same state as the room temperature. Here, the temperature at that time is T0.

  FIG. 21 shows a difference (PV value) between the maximum value and the minimum value of the output value of the reflective optical sensor 2245 for each lighting light emitting unit, which is obtained from the result of FIG. The PV value for each lighting light emitting unit is acquired before the operation of the printer control apparatus 2090 is started, and is stored in the memory of the printer control apparatus 2090 as pre-operation information.

  When the fixing belt 502 is replaced with a new one due to long-term use of the color printer 2000 or the like, immediately after the replacement, the PV value for each lighting light emitting unit is acquired in the same manner as described above, and the printer controller 2090 Update the pre-operation information stored in the memory.

  FIG. 22 shows a timing 28 after the start of operation of the color printer 2000 when the light-shielding member 100a is in the “closed state” and the 20 light emitting units from the group 2 to the group 6 are individually turned on. The outputs of the light receiving parts are shown.

  If the timing is after the print job, the temperature in the vicinity of the reflective optical sensor 2245 is higher than room temperature because the fixing device 2050 is in operation. If the temperature at this time is T1, generally T1> T0. The peak value of the light receiving unit output at this timing is smaller than that before the start of operation in any light emitting unit. This is partly because the light output is lowered because the temperature of each light emitting section is high. Moreover, the fall of the light output by a time-dependent change is also included. The temperature T1 is preferably known, but the effect is not changed even if it is not known.

  FIG. 23 shows a difference (PV value) between the maximum value and the minimum value of the output of the reflective optical sensor 2245 for each lighting light emitting unit, which is obtained from the result of FIG.

  In FIG. 24, for each light emitting unit, a value obtained by dividing the PV value shown in FIG. 23 by the PV value shown in FIG. 21 is shown as the light amount correction coefficient. The light quantity correction coefficient indicates a value in the vicinity of 0.65 for each light emitting unit.

  The light amount correction coefficient indicates a change in the light emission amount of each light emitting unit at an arbitrary timing (temperature T1) after the start of operation when the operation before the start of operation of the color printer 2000 (temperature T0) is used as a reference. Note that a change in light emission amount of each light emitting unit due to a change with time at an arbitrary timing (time t) after the start of operation, including time 0 before the start of operation, is included. If attention is paid to one light emitting portion, the light emission amount changes due to temperature change or temporal change, and if attention is paid to 20 light emitting portions, it is also a change in light emission amount variation between the light emitting portions due to temperature change or temporal change.

  FIG. 25 shows 28 light reception timings when the light amount correction coefficient is obtained and when the light-shielding member 100a is in the “open state” and the 20 light emitting units from the group 2 to the group 6 are individually turned on. The output of the part is shown.

  FIG. 26 shows the result of calculating the sum of the output values of the light receiving units shown in FIG. 25 for each light emitting unit. That is, for each light emitting unit, the amount of light emitted from the light emitting unit, reflected by the fixing belt 502, and received by the reflective optical sensor 2245 is meant. The light receiving units for obtaining the sum of outputs may be all 28 light receiving units, or a number smaller than 28 consisting of a light receiving unit having the maximum output and a plurality of light receiving units close to the light receiving unit. The light receiving unit may be selected. Since this depends on the optical system of the reflective optical sensor 2245, it may be determined in advance by experiments or the like.

  FIG. 26 includes surface information of the fixing belt. However, this surface information is the surface information detected at the temperature T1 and the elapsed time t. This is sufficient if relative surface information at a certain timing is desired. However, in order to grasp the change compared with the surface information at different temperatures and different elapsed times, absolute surface information in which the light emission amount change of the light emitting part is corrected is required.

  FIG. 27 shows the result of dividing the sum of the output values of each light receiving unit in FIG. 26 by the light amount correction coefficient for each light emitting unit. This result is obtained by quantitatively converting the surface information detected at the temperature T1 and the elapsed time t into the surface information at the temperature T0 and the elapsed time 0.

  The change in the output value of each light receiving part is not only the change in the light emission amount of the light emitting part, but also the reflection including the temperature change and time change of the light receiving sensitivity of the light receiving part and the temperature change and time change of the optical characteristics of the optical system. Needless to say, this is caused by a change in characteristics of the optical sensor. However, it has been found that the change in the light receiving sensitivity is sufficiently smaller than the change in the light emission amount, and the influence of the change in the optical characteristics is sufficiently small.

  By the way, T1 <T0 may be satisfied depending on the timing. In this case, when the increase in the light emission amount due to the temperature decrease is larger than the decrease in the light emission amount due to the change with time at this timing, the light amount correction coefficient becomes a value of 1 or more.

  Here, a pre-operation information acquisition process for acquiring the pre-operation information performed by the printer control device 2090 using the reflective optical sensor 2245 before the operation of the color printer 2000 is started will be described with reference to FIG. The flowchart in FIG. 28 corresponds to a series of processing algorithms executed by the CPU of the printer control apparatus 2090 during the pre-operation information acquisition process.

  In the first step 401, the light shielding member 100a is set to the “closed state” via the driving device 100b. If the light shielding member 100a is already in the “closed state”, the process in step 401 is skipped.

  In the next step S403, an initial value 1 is set to a variable m indicating the number of repetitions.

  In the next step S405, an initial value 2 is set in a variable p indicating a set.

  In the next step S407, an initial value 4 is set to a variable q indicating the light emitting unit in the set p.

  In the next step S409, the light emitting unit Epq is turned on. That is, the light emitting unit Epq is a lighting light emitting unit.

  In the next step S411, an output signal of the light receiving unit corresponding to the light emitting unit Epq is acquired. In this embodiment, as an example, when light is emitted from one light emitting unit, the total of the light receiving unit having the maximum output and the two light receiving units positioned on the + y side and the −y side of the light receiving unit, respectively. The five light receiving portions are light receiving portions corresponding to one light emitting portion.

  In the next step S413, the light emitting unit Epq is turned off.

  In the next step S415, the output signal of the light receiving unit corresponding to the light emitting unit Epq is stored in the memory of the printer control device 2090 in association with the light emitting unit Epq.

  In the next step S417, it is determined whether or not the value of q exceeds 1. If the value of q exceeds 1, the determination here is affirmed and the process proceeds to step S419.

  In step S419, the value of q is decremented by 1, and the process returns to step S409.

  Thereafter, the processes in steps S409 to S419 are repeated until the determination in step S417 is denied.

  When the value of q becomes 1, the determination in step S417 is denied, and the process proceeds to step S421.

  In step S421, it is determined whether the value of p is less than 6. If the value of p is less than 6, the determination here is affirmed and the process proceeds to step S423.

  In step S423, the value of p is incremented by 1, and the process returns to step S407.

  Thereafter, the processes in steps S407 to S423 are repeated until the determination in step S421 is denied.

  When the value of p becomes 6, the determination in step S421 is denied, and the process proceeds to step S425.

  In step S425, it is determined whether or not the value of m is less than a preset integer M (M ≧ 2). If the value of m is less than M, the determination here is affirmed and the process proceeds to step S427.

  In step S427, the value of m is incremented by 1, and the process returns to step S405.

  Thereafter, the processes in steps S405 to S427 are repeated until the determination in step S425 is denied.

  When the value of m becomes M, the determination in step S425 is denied, and the process proceeds to step S429.

  In this step S429, the output signal of the light receiving unit corresponding to the lighting light emitting unit at each lighting timing is read from the memory, and the average value, median value, and abnormal value of the M output values of each light receiving unit are removed for each light emitting unit. Either the average value or the median value excluding the abnormal value is obtained as the detected value. If M is 5 or more, the average value of three or more output values excluding the maximum and minimum values, the median value, the average value excluding abnormal values, or the median value excluding abnormal values May be obtained as a detection value.

  In the next step S431, the minimum value is subtracted from the maximum value of the detection value for each light emitting unit. Here, the subtraction result obtained for each light emitting unit is the pre-operation information.

  In the next step S433, the pre-operation information obtained in step S431 is stored in the memory of the printer control apparatus 2090. Then, the pre-operation information acquisition process ends.

  When the number of printed sheets exceeds a predetermined number (for example, 1000 sheets), the printer controller 2090 prints a predetermined number (for example, 500 sheets) of A4 recording paper in a vertical state, The surface state of the fixing belt 502 is checked using the reflective optical sensor 2245 when printing in a state or when printing A3 recording paper. This surface state check process will be described with reference to FIGS. The flowcharts of FIGS. 29 to 31 correspond to a series of processing algorithms executed by the CPU of the printer control apparatus 2090 during the surface state check process.

  In the first step S501, the light shielding member 100a is set to the “closed state” via the driving device 100b. If the light shielding member 100a is already in the “closed state”, the process in step S501 is skipped.

  In the next step S503, an initial value 1 is set to a variable m indicating the number of repetitions.

  In the next step S505, an initial value 2 is set in a variable p indicating a set.

  In the next step S507, an initial value 4 is set to a variable q indicating the light emitting unit in the set p.

  In the next step S509, the light emitting unit Epq is turned on. That is, the light emitting unit Epq is a lighting light emitting unit.

  In the next step S511, an output signal of the light receiving unit corresponding to the light emitting unit Epq is acquired.

  In the next step S513, the light emitting unit Epq is turned off.

  In the next step S515, the output signal of the light receiving unit corresponding to the light emitting unit Epq is stored in the RAM of the printer control device 2090 in association with the light emitting unit Epq.

  In the next step S517, it is determined whether or not the value of q exceeds 1. If the value of q exceeds 1, the determination here is affirmed, and the routine goes to Step S519.

  In step S519, the value of q is decremented by 1, and the process returns to step S509.

  Thereafter, the processes in steps S509 to S519 are repeated until the determination in step S517 is denied.

  When the value of q becomes 1, the determination in step S517 is denied, and the process proceeds to step S521.

  In this step S521, it is determined whether or not the value of p is less than 6. If the value of p is less than 6, the determination here is affirmed and the process proceeds to step S523.

  In step S523, the value of p is incremented by 1, and the process returns to step S507.

  Thereafter, the processes in steps S507 to S523 are repeated until the determination in step S521 is denied.

  When the value of p becomes 6, the determination in step S521 is denied, and the process proceeds to step S525.

  In step S525, it is determined whether or not the value of m is less than a preset integer M (M ≧ 2). If the value of m is less than M, the determination here is affirmed and the process proceeds to step S527.

  In step S527, the value of m is incremented by 1, and the process returns to step S505.

  Thereafter, the processes in steps S505 to S527 are repeated until the determination in step S525 is denied.

  When the value of m becomes M, the determination in step S525 is denied and the process proceeds to step S601.

  In step S601, the light shielding member 100a is set to the “open state” via the driving device 100b.

  In the next step S603, an initial value 1 is set to a variable m indicating the number of repetitions.

  In the next step S605, an initial value 2 is set in a variable p indicating a set.

  In the next step S607, an initial value 4 is set to a variable q indicating the light emitting unit in the set p.

  In the next step S609, the light emitting unit Epq is turned on. That is, the light emitting unit Epq is a lighting light emitting unit.

  In the next step S611, an output signal of the light receiving unit corresponding to the light emitting unit Epq is acquired.

  In the next step S613, the light emitting unit Epq is turned off.

  In the next step S615, the output signal of the light receiving unit corresponding to the light emitting unit Epq is stored in the memory of the printer control device 2090 in association with the light emitting unit Epq.

  In the next step S617, it is determined whether or not the value of q exceeds 1. If the value of q exceeds 1, the determination here is affirmed and the process proceeds to step S619.

  In step S619, the value of q is decremented by 1, and the process returns to step S609.

  Thereafter, the processes in steps S609 to S619 are repeated until the determination in step S617 is denied.

  When the value of q becomes 1, the determination in step S617 is denied, and the process proceeds to step S621.

  In step S621, it is determined whether or not the value of p is less than 6. If the value of p is less than 6, the determination here is affirmed and the process proceeds to step S623.

  In step S623, the value of p is incremented by 1, and the process returns to step S607.

  Thereafter, the processes in steps S607 to S623 are repeated until the determination in step S621 is denied.

  When the value of p becomes 6, the determination in step S621 is denied, and the process proceeds to step S625.

  In this step S625, it is determined whether or not the value of m is less than a preset integer M (M ≧ 2). If the value of m is less than M, the determination here is affirmed and the process proceeds to step S627.

  In step S627, the value of m is incremented by 1, and the process returns to step S605.

  Thereafter, the processing from step S605 to step S627 is repeated until the determination at step S625 is negative.

  When the value of m becomes M, the determination in step S625 is denied, and the process proceeds to step S629.

  In this step 629, the light shielding member 100a is brought into the “closed state” via the driving device 100b. As described above, by keeping the light shielding member 100a in the “closed state” except when necessary, it is possible to suppress the temperature of the reflective optical sensor 2245 from being increased by the heat from the fixing device 2050.

  In the next step S701, the output signal of the light receiving unit corresponding to the lighting light emitting unit at each lighting timing acquired when the light shielding member 100a is in the “closed state” is read from the memory, and the M of each light receiving unit is read for each light emitting unit. Any one of an average value, a median value, an average value excluding abnormal values, and a median value excluding abnormal values is obtained as the first detection value. If M is 5 or more, the average value of three or more output values excluding the maximum and minimum values, the median value, the average value excluding abnormal values, or the median value excluding abnormal values May be obtained as the first detection value.

  In the next step S703, the minimum value is subtracted from the maximum value of the first detection value for each light emitting unit.

  In the next step S705, the pre-operation information stored in the memory is read out, and for each light emitting unit, the subtraction result obtained in step S703 is divided by the pre-operation information to calculate a light amount correction coefficient. The light amount correction coefficient for each light emitting unit calculated here is temporarily stored in the memory.

  In the next step S707, the output signal of the light receiving unit corresponding to the lighting light emitting unit at each lighting timing acquired when the light shielding member 100a is in the “open state” is read from the RAM, and the M of each light receiving unit is read for each light emitting unit. Any one of an average value, a median value, an average value excluding abnormal values, and a median value excluding abnormal values is obtained as the second detection value. If M is 5 or more, the average value of three or more output values excluding the maximum and minimum values, the median value, the average value excluding abnormal values, or the median value excluding abnormal values May be obtained as the second detection value.

  In the next step S709, the second detection value-the first detection value is calculated for each light receiving unit for each light emitting unit to obtain a third detection value. Thereby, it is possible to obtain the output value of each light receiving unit when only the light reflected by the fixing belt 502 is received.

  In the next step S711, the third detection values of the respective light receiving parts are added together for each light emitting part to obtain a fourth detection value.

  In the next step S713, the fourth detection value / light quantity correction coefficient is calculated for each light emitting unit to obtain a fifth detection value. An example of the fifth detection value for each light emitting unit is shown in FIG.

  In the next step S715, the lighting light emitting unit in FIG. 32 is converted into a light irradiation position, and the relationship between the light irradiation position and the fifth detection value is obtained (see FIG. 33).

  In the next step S717, with respect to the fifth detection value, values at two light irradiation positions adjacent to each other in the y-axis direction are connected by a straight line (see FIG. 34), and the inclination is set at the midpoint between the two light irradiation positions. The differential value of And the relationship between a light irradiation position and a differential value is calculated | required (refer FIG. 35). Note that the method of obtaining the differential value is not limited to this. For example, the values at both ends of three consecutive light irradiation positions may be connected with a straight line, and the slope may be a differential value at the central light irradiation position among the three.

  In the next step S719, it is determined whether or not there is a scratch. Here, if there is a differential value whose absolute value exceeds 20 (au), it is determined that there is a scratch, and the process proceeds to the next step S721.

  In step S721, a scratched position is obtained. Here, when the derivative value changes from a value smaller than −20 (au) to a value larger than +20 (au), the position where the derivative value becomes 0 (au), A so-called zero cross position is obtained (see FIG. 36). The light irradiation position corresponding to this zero cross position is a position with a flaw. In FIG. 36, it is determined that there is a scratch at a position of 12.5 mm.

  In the next step S723, a parameter related to the depth of the flaw (hereinafter abbreviated as “depth parameter”) is obtained. By the way, it is thought that the fall of the intensity | strength of the reflected light received by a light-receiving part is so large that the depth of a damage | wound is deep. That is, the amount of decrease in the reflected light intensity corresponds to the depth of the scratch.

  Therefore, although the depth parameter of the scratch may be obtained from the detection value at the position where the scratch is present, the light irradiation position and the detection value are determined due to the attachment error of the reflective optical sensor 2245, the inclination of the fixing belt 502, and the like. In some cases, an inclination component is superimposed on the relationship.

  In this case, first, the relationship between the light irradiation position and the differential value is referred to, and the light irradiation position that is clear that there is no flaw is obtained on the −y side and the + y side of the flawed position (see FIG. 37). In FIG. 37, it is clear that the differential value is close to 0 at the light irradiation position of 6 mm and 15 mm and there is no scratch.

  Next, in the relationship between the light irradiation position and the fifth detection value, the fifth detection values at two light irradiation positions that are clearly free of scratches are connected by a straight line L (see FIG. 38). The inclination of the straight line L is the inclination component.

  Next, an average value of two fifth detection values sandwiching the scratched position or a smaller value is set as a detection value at the scratched position.

  Next, the difference k (see FIG. 38) between the value of the straight line L at the scratched position and the fifth detection value at the scratched position is calculated. In FIG. 38, k is 63.1 (au), which corresponds to about 16% as the rate of decrease in reflected light intensity. K calculated here is a depth parameter, and the larger the value of k, the deeper the flaw. Here, the relationship between the value of k and the image quality is acquired in advance through experiments or the like and stored in the memory.

  In the next step S725, the width of the flaw is obtained. Here, the width of the light irradiation position corresponding to k / 2 is the width w of the scratch (see FIG. 39). In FIG. 39, the width w of the scratch is about 3 mm. Then, the surface state check process ends.

  In step S719, if the absolute value of all the differential values is 20 (au) or less, it is determined that there is no flaw and the surface state check process is terminated.

  In the present embodiment, the influence of the reflection at the opening member 47 is removed from the light receiving unit output when the light reflected by the fixing belt 502 is received, and the temperature change and temporal change of the reflective optical sensor 2245 are removed. Since the influence is corrected, the flawed position, flaw depth parameter, and flaw width on the fixing belt 502 can be obtained with high accuracy.

  When at least one of the flaw depth parameter and the flaw width exceeds a preset threshold value, the printer controller 2090 displays a flaw on the surface of the fixing belt 502 on the operation panel display. A flaw position, a flaw depth parameter, and a flaw width are displayed together with a message indicating that there is a flaw. The operator notifies the maintenance company of the display content of the display. This information may be automatically notified from the color printer 2000 to the maintenance company via a public line.

  The maintenance company scrapes the surface of the fixing belt 502 in accordance with the position of the scratch, the depth parameter of the scratch, and the width of the scratch. In this case, since the position with the flaw, the flaw depth parameter, and the flaw width are obtained with high accuracy, insufficient cutting or excessive cutting can be prevented. That is, maintenance of the fixing belt 502 can be performed appropriately. Therefore, the printer control apparatus 2090 can suppress a decrease in image quality and can stably form a good image.

  As is apparent from the above description, in this embodiment, the timing before the start of operation of the color printer 2000 corresponds to the first usage state of the present invention, and the timing at which the surface state check process is performed is the second. Corresponds to the usage situation.

  The light blocking mechanism 100 constitutes the light incident adjusting mechanism of the present invention. Here, the “open state” is the first state, and the “closed state” is the second state. Further, the printer control apparatus 2090 constitutes the processing apparatus of the present invention.

  And the sensing method of this invention is implemented in the pre-operation information acquisition process and the surface state check process. Here, the detection value in the pre-operation information acquisition process is the first output value, and the first detection value in the surface state check process is the second output value.

  In the present embodiment, the processing shown in the flowcharts of FIGS. 28 to 31 performed by the CPU of the printer control apparatus 2090 is stored in the memory (recording medium) of the printer control apparatus 2090 as a program.

  As described above, according to the color printer 2000 according to the present embodiment, the optical scanning device 2010, the four image forming stations, the intermediate transfer belt 2040, the secondary transfer roller 2042, the fixing device 2050, the reflective optical sensor 2245, the light shielding. A mechanism 100, an operation panel, a printer control device 2090, and the like are provided.

  The reflective optical sensor 2245 is disposed along the substrate 45, the frame member 46, the y-axis direction, 28 light emitting units (E11 to E74) that emit light toward the fixing belt 502, and 7 illumination lenses. (EL1 to EL7) One light receiving lens DL, and 28 light receiving portions (D1 to D28) that are arranged at equal intervals along the y-axis direction and receive the light reflected by the fixing belt 502, etc. Have.

  And since the several light emission part respond | corresponds to one lens for illumination, the structure of a lens member can be simplified.

  The light shielding mechanism 100 includes a light shielding member 100a and a driving device 100b that moves the light shielding member 100a in the x-axis direction, and can selectively select an “open state” and a “closed state” of the light shielding member 100a.

  Before the operation of the color printer 2000 is started, the printer control device 2090 obtains the output signal of the reflective optical sensor 2245 obtained when the light shielding member 100a is in the “closed state” as pre-operation information, and In the surface state check process performed after the operation of the printer 2000 is started, the light amount correction coefficient is calculated from the output signal of the reflective optical sensor 2245 obtained when the light shielding member 100a is in the “closed state” and the pre-operation information. To do.

  Since the difference (PV value) between the maximum value and the minimum value in the output values of the plurality of light receiving units is used when obtaining the light amount correction coefficient, the noise component included in the output value can be reduced. The accuracy of the correction coefficient can be improved.

  Then, in the surface state check process, the printer control device 2090 removes the influence of reflection at the opening member 47 on the output signal of the reflective optical sensor 2245 obtained when the light shielding member 100a is in the “open state”. In addition, since the influence of temperature change and temporal change of the reflective optical sensor 2245 is corrected using the light amount correction coefficient, the position of the flaw on the fixing belt 502, the flaw depth parameter, and the flaw width are conventionally determined. More accurately.

  As a result, the fixing belt 502 can be properly maintained, and the color printer 2000 can suppress a decrease in image quality and can stably form a good image.

  Further, the light shielding member 100a has heat resistance, and when in the “closed state”, the heat from the fixing belt 502 is prevented from being directly transmitted to the reflection type optical sensor 2245. Therefore, the reflection type optical sensor 2245 has heat resistance. There is no need to have. That is, the cost increase of the reflective optical sensor 2245 can be suppressed.

  In the above-described embodiment, the case where the difference (PV value) between the maximum value and the minimum value in the output values of the plurality of light receiving units is used when obtaining the light amount correction coefficient has been described. However, the present invention is not limited to this. . For example, when the noise component contained in the output value of the light receiving unit is small, the sum of the output values of a plurality of light receiving units (for example, 28 light receiving units D1 to D28) may be used. Also, a value obtained by subtracting the minimum value from the sum of the output values of the plurality of light emitting units close to the maximum value and the maximum value may be used.

  Moreover, although the said embodiment demonstrated the case where the number of groups was seven, it is not limited to this.

  Moreover, although the said embodiment demonstrated the case where the number of the light emission parts contained in one group was four, it is not limited to this.

  Moreover, although the said embodiment demonstrated the case where the number of light emission parts and the number of light receiving parts were equal, it is not limited to this. The number of light receiving parts may be smaller than the number of light emitting parts. In this case, electronic components such as operational amplifiers can be reduced, and cost reduction can be achieved. Moreover, you may use what has a single light-receiving surface as a light-receiving part.

  In short, the reflective optical sensor 2245 has N (≧ 1) light emitting units arranged in one direction and K (K ≧ 1) light receiving units that receive the reflected light from the fixing belt 502. It should be.

  In the above-described embodiment, the illumination lens may be enlarged and used as the light receiving lens.

  Moreover, although the said embodiment demonstrated the case where 20 light emission parts of the groups 2-6 were used in the pre-operation information acquisition process, it is not limited to this.

  Further, in the pre-operation information acquisition process of the above-described embodiment, the case of repeating M times has been described, but the repetition may not be performed (see FIG. 40). In this case, the output value of each light receiving unit is the detection value.

  In the above embodiment, in the surface state check process, after obtaining the output signal of the reflective optical sensor 2245 when the light shielding member 100a is in the “closed state”, the reflective type when the light shielding member 100a is in the “open state”. Although the case where the output signal of the optical sensor 2245 is acquired has been described, the present invention is not limited to this. After obtaining the output signal of the reflective optical sensor 2245 when the light shielding member 100a is in the “open state”, the output signal of the reflective optical sensor 2245 when the light shielding member 100a is in the “closed state” may be obtained.

  Moreover, although the said embodiment demonstrated the case where 20 light emission parts of the groups 2-6 were used in the surface state check process, it is not limited to this.

  Further, in the surface state check process of the above-described embodiment, a case has been described where M times are repeated when the light shielding member 100a is in the “closed state”, but the repetition may not be performed (see FIG. 41). In this case, the output value of each light receiving unit becomes the first detection value, and the step S701 is unnecessary.

  Further, in the surface state check process of the above-described embodiment, a case has been described in which M times of repetition are performed when the light shielding member 100a is in the “open state”, but the repetition may not be performed (see FIG. 42). In this case, the output value of each light receiving unit becomes the second detection value, and step S707 is unnecessary. Of course, the flowchart of FIG. 41 and the flowchart of FIG. 42 may be combined.

  In the surface state check process of the above embodiment, when the influence of reflection at the opening member 47 is small, the second detection value may be used as it is as the third detection value. In this case, step S709 is not necessary.

  Moreover, although the said embodiment demonstrated the case where the arrangement pitch of several light-receiving parts was 1 mm, it is not limited to this.

  Moreover, although the said embodiment demonstrated the case where the formation pitch of several light spots was 1 mm, it is not limited to this.

  Moreover, although the said embodiment demonstrated the case where the some lens for illumination and one light reception lens were integrated, it is not limited to this.

  Moreover, although the said embodiment demonstrated the case where a some light emission part was lighted sequentially sequentially, it is not limited to this. For example, a plurality of light emitting units may be turned on simultaneously. In this case, one light receiving unit corresponds to one light emitting unit.

  Further, in the above-described embodiment, a processing device may be provided in the reflective optical sensor 2245, and the processing device may perform at least a part of the processing in the printer control device 2090 in the pre-operation information acquisition processing and the surface state check processing. .

  Further, in the above embodiment, as shown in FIG. 43A and FIG. 43B as an example, the driving device 100b of the light shielding mechanism 100 rolls up the light shielding member 100a to open the light shielding member 100a in the “open state”. "It may be." In this case, the arrangement space of the light shielding mechanism 100 can be reduced.

  Moreover, although the said embodiment demonstrated the case where the light-shielding mechanism 100 had the light-shielding member 100a and the drive device 100b, it is not limited to this. In short, the first state in which the light emitted from the reflective optical sensor 2245 and reflected by the fixing belt 502 is incident on the reflective optical sensor 2245, and the reflected light of the light emitted from the reflective optical sensor 2245 is reflected into the reflective optical sensor. It is only necessary that the second state not incident on 2245 can be selected alternatively.

  For example, as shown in FIGS. 44A and 44B, the reflective optical sensor 2245 is rotated so that the light emitted from the reflective optical sensor 2245 travels in a different manner from the fixing belt 502. A rotary driving device (not shown) may be used instead of the driving device 100b. In this case, the light shielding member 100a may be omitted, but the light shielding member 100a is preferably disposed in front of the rotated reflective optical sensor 2245.

  In the above-described embodiment, the case where the length of the light shielding member 100a in the y-axis direction is the same as or slightly longer than the width of the fixing belt 502 (the length in the y-axis direction) has been described. is not. For example, when downsizing is prioritized over the heat shielding effect, the length of the light shielding member 100a in the y-axis direction may be shorter than the width of the fixing belt 502. However, even in this case, the length of the light shielding member 100a in the y-axis direction is preferably longer than the length of the reflective optical sensor 2245 in the y-axis direction.

  In the above embodiment, the frame member 46 may be composed of four side plates.

  Moreover, although the said embodiment demonstrated the case where the several light emission part was arrange | positioned along the y-axis direction, it is not limited to this, The several light emission part inclined with respect to the y-axis direction You may arrange | position along a direction.

  For example, as shown in FIG. 45, the detection range when a plurality of light emitting units are arranged along the y-axis direction is A, and the plurality of light emitting units are along a direction inclined by 45 ° with respect to the y-axis direction. When the detection range is A ′, the detection range A ′ is 1 / √2 times as small as the detection range A, but the position of the flaw on the fixing belt 502 and the state of the flaw (depth of the flaw) , The position resolution when obtaining the width of the scratch) can be increased.

  Moreover, although the said embodiment demonstrated the case where one reflection type optical sensor 2245 was provided, it is not limited to this. For example, as shown in FIG. 46, a reflective optical sensor 2245 may also be provided at a position facing the + y side flaw occurrence site. Further, when there are three or more scratched sites corresponding to a large number of recording papers, a reflective optical sensor 2245 may be provided for each scratched site.

  In the above embodiment, at least a part of the processing according to the program by the CPU of the printer control device 2090 may be configured by hardware, or all may be configured by hardware.

  In the above embodiment, the case where the reflection optical sensor 2245 is used to detect the position of the flaw, the flaw depth parameter, and the flaw width on the surface of the fixing belt 502 has been described. However, the present invention is not limited to this. Instead, at least one of a flaw position, a flaw depth parameter, and a flaw width may be detected.

  In the above-described embodiment, the case where the reflection-type optical sensor 2245 is used to detect the vertical streak on the surface of the fixing belt 502 has been described. However, the present invention is not limited to this. For example, a scratch caused by contact with the separation claw 506 or the temperature sensor may be detected using the reflective optical sensor 2245.

  While the width of the vertical streak is several hundred μm to several mm, the width of the scratch caused by contact with the separation claw 506 and the temperature sensor is several tens μm to several hundred μm. In addition, the occurrence position of scratches caused by contact with the separation claw 506 and the temperature sensor is almost determined. Therefore, it is easy to distinguish a vertical streak from a scratch caused by contact with the separation claw 506 or the temperature sensor.

  Further, the reflection type optical sensor 2245 may be used to detect foreign matter (for example, toner) adhering to the surface of the fixing belt 502.

  Further, the surface state of the moving body other than the fixing belt 502 may be detected by using the reflective optical sensor 2245.

  In the above-described embodiment, the case of a tandem multi-color printer that forms a full-color image by superimposing four colors (black, cyan, magenta, and yellow) has been described as an image forming apparatus. Is not to be done. For example, it may be a multicolor printer that further uses auxiliary colors, or a printer that forms a monochrome image.

  In the above-described embodiment, the case of a color printer has been described as the image forming apparatus. However, the present invention is not limited to this, and an image forming apparatus other than a printer, for example, a copier, a facsimile, or a multifunction machine in which these are integrated. There may be.

  Further, in an apparatus other than the image forming apparatus, the reflective optical sensor 2245 may be used to detect the surface state of the object.

  45 ... Substrate, 46 ... Frame member, 47 ... Opening member, 100 ... Light shielding mechanism (light incident adjustment mechanism), 100a ... Light shielding member (plate member), 100b ... Drive device, 501 ... Pressure roller, 502 ... Fixing belt ( (Moving body, object), 503 ... fixing roller, 504 ... heating roller, 505 ... tension roller, 2000 ... color printer (image forming apparatus), 2010 ... light scanning device, 2030a-2030d ... photosensitive drum, 2040 ... intermediate transfer Belt, 2050 ... Fixing device, 2090 ... Printer control device (processing device), 2245 ... Reflective optical sensor (sensor), D1 to D28 ... Light receiving portion, DL ... Light receiving lens, E11 to E74 ... Light emitting portion, EL1 to EL7 ... lighting lens.

Japanese Patent Laid-Open No. 5-113737 Japanese Patent No. 4632820

Claims (10)

A sensor having a light emitting part and a light receiving part for emitting light toward the moving body;
Regarding the usage time, the light emitting unit is turned on when the moving body is in a first usage state, and the output of the sensor is acquired as a first output value. The usage time of the mobile body is longer than that in the first usage state. The light emitting unit is turned on in a long second usage state, and the output of the sensor is acquired as a second output value. Based on the first output value and the second output value, the moving body is An image forming apparatus comprising: a processing device that corrects an output of the sensor when light emitted from the sensor and reflected by the moving body in the second usage state enters the sensor. A part of the light when the light emitting unit is turned on is scattered inside the sensor and received by the light receiving unit,
The image forming apparatus according to claim 1, wherein when acquiring the first output value and the second output value, reflected light of light emitted from the sensor does not enter the sensor.   The processing device according to claim 1, wherein a value obtained by dividing the second output value by the first output value is used as a light amount correction coefficient, and the correction is performed using the light amount correction coefficient. Image forming apparatus.   The processing device emits light from the sensor based on an output of the sensor when light that is emitted from the sensor and reflected by the movable body is incident on the sensor when the movable body is in the second usage state. The surface information of the moving body is obtained based on a result obtained by subtracting the output of the sensor when the reflected light of the emitted light is not incident on the sensor and then dividing by the light amount correction coefficient. The image forming apparatus according to 3.   5. The image forming apparatus according to claim 4, wherein the surface information of the moving body is streak-like flaw information extending in a moving direction of the moving body.   The image forming apparatus according to claim 5, wherein the flaw information is information on at least one of a flaw position and a flaw depth.   The image forming apparatus according to claim 1, wherein the movable body is a fixing belt. A sensing method using a sensor having a light emitting part and a light receiving part for emitting light toward an object,
In the sensor, a part of the light when the light emitting unit is turned on is scattered inside the sensor and received by the light receiving unit,
The light output unit is turned on when the object is in the first use state with respect to the use time, and the reflected light of the light emitted from the sensor does not enter the sensor, and the output of the sensor is the first output. A process for obtaining a value;
The light emitting unit is turned on when the object is in a second usage situation that is longer than the first usage situation, so that the reflected light of the light emitted from the sensor does not enter the sensor. Obtaining the output of the sensor as a second output value;
When the object is in the second usage state, light emitted from the sensor and reflected by the object is incident on the sensor, and the output of the sensor is converted into the first output value and the second detection value. Correcting based on:
Obtaining surface information of the object based on the corrected output of the sensor. A program used for an apparatus including a sensor having a light emitting unit and a light receiving unit that emits light toward an object,
In the sensor, a part of the light when the light emitting unit is turned on is scattered inside the sensor and received by the light receiving unit,
The light output unit is turned on when the object is in the first use state with respect to the use time, and the reflected light of the light emitted from the sensor does not enter the sensor, and the output of the sensor is the first output. The procedure to obtain as a value,
The light emitting unit is turned on when the object is in a second usage situation that is longer than the first usage situation, so that the reflected light of the light emitted from the sensor does not enter the sensor. , A procedure for obtaining the output of the sensor as a second output value;
When the object is in the second usage state, light emitted from the sensor and reflected by the object is incident on the sensor, and the output of the sensor is converted into the first output value and the second detection value. Correction procedure based on
A program for causing a control computer of the apparatus to execute a procedure for obtaining surface information of the object based on the corrected output of the sensor.   A computer-readable recording medium on which the program according to claim 9 is recorded.