JP6406543B2 - Image forming apparatus and object processing apparatus. - Google Patents

Description

  The present invention relates to an image forming apparatus and an object processing apparatus, and more particularly to an image forming apparatus that forms an image on a recording medium and an object processing apparatus that processes an object.

  2. Description of the Related Art Conventionally, an image forming apparatus that obtains surface information of a fixing member (moving body) for fixing an image on a recording medium using a reflective optical sensor is known (see, for example, Patent Document 1).

  However, the image forming apparatus disclosed in Patent Document 1 cannot stably and accurately obtain the surface information of the moving body.

The present invention has at least one moving body for fixing the image, and a light source composed of at least one light emitting unit, which is brought into contact with a recording medium to which the image is transferred, and irradiates the moving body with light. A reflection type optical sensor including at least one irradiation system; and a processing device for obtaining surface information of the moving body based on an output signal of the reflection type optical sensor, the light from the light source on the moving body irradiation region formed in the better direction width than the width of the moving direction of the movable body perpendicular to the movement direction rather narrow, the reflective optical sensor is movable in a direction intersecting the moving direction And the processing device has surface information of the movable body based on output signals of the reflective optical sensor when the reflective optical sensor is located at each of a plurality of positions with respect to a direction intersecting the moving direction. An image forming apparatus and obtaining.

  According to the present invention, the surface information of the moving body can be obtained stably and accurately.

1A to 1C are views (No. 1 to No. 3) for explaining a color printer according to an embodiment, respectively. It is a figure for demonstrating the fixing device of FIG. 1 (A). FIGS. 3A and 3B are views (No. 1 and No. 2) for explaining the reflection type optical sensor, respectively. It is FIG. (3) for demonstrating a reflection type optical sensor. It is FIG. (4) for demonstrating a reflection type optical sensor. FIGS. 6A and 6B are views (No. 5 and No. 6) for explaining the reflective optical sensor. It is a flowchart for demonstrating an example of operation | movement of a surface information detection apparatus. FIGS. 8A and 8B are graphs showing the PD output in a state where the light shielding member is located at the shielding position and the retracted position, respectively. It is a figure which shows a mode that the light from LED is reflected by an opening body, and injects into PD. FIG. 10A is a graph showing PD output for lighting of each LED at 25 ° C. in a state where the light shielding member is positioned at the shielding position, and FIG. 10B is a diagram where the light shielding member is positioned at the retracted position. 11 is a graph showing a value (PD output) obtained by subtracting the PD output shown in FIG. 10 (A) from the PD output with respect to lighting of each LED at 25 ° C. in the above state. FIG. 11A is a graph showing PD output for lighting of each LED at 70 ° C. in a state where the light shielding member is located at the shielding position, and FIG. 11B is a diagram where the light shielding member is located at the retracted position. 12 is a graph showing a value (PD output) obtained by subtracting the corresponding PD output shown in FIG. 11A from the PD output for lighting of each LED at 70 ° C. in the above state. Sum of PD output for each LED shown in FIG. 10B (light quantity variation correction coefficient at 25 ° C.), and sum of PD output for each LED in FIG. 11B (light quantity variation correction coefficient at 70 ° C.) It is a graph which shows. FIG. 13A is a graph showing values (temperature coefficients) obtained by dividing the light amount variation correction coefficient for each LED in a plurality of temperature environments by the light amount variation correction coefficient for the LED at 25 ° C. FIG. 13B is a graph obtained by rewriting FIG. 13A with the temperature on the horizontal axis. It is a graph which shows the result of having corrected the light quantity variation of each LED in a plurality of temperature environments using the corresponding light quantity variation correction coefficient. It is a graph which shows the result (PD output sum) which correct | amended the measured value (PD output sum) in a reflection type optical sensor using the light quantity variation correction coefficient. It is a flowchart (the 1) for demonstrating an example of the surface information detection method. It is a flowchart (the 2) for demonstrating an example of the surface information detection method. It is a graph which shows the light quantity dispersion | variation in each LED in a several temperature environment when the surface information detection method shown by FIG.16 and FIG.17 is performed and a reflection type optical sensor is used for a long time. It is a flowchart for demonstrating the other example of the surface information detection method. 20A and 20B are diagrams for explaining the movement operation of the surface information detection apparatus. FIG. 21A and FIG. 21B are diagrams for explaining the movement operation of the reflective optical sensor. 22A and 22B are views (No. 1 and No. 2) for explaining an example of the light shielding member, respectively. It is a figure for demonstrating the other example of a light shielding member. It is a flowchart for demonstrating the other example of operation | movement of a surface information detection apparatus. FIG. 25A is a graph showing the reflected light intensity from the fixing belt, and FIG. 25B is a graph showing the differential value of the reflected intensity from the fixing belt. FIGS. 26A and 26B are diagrams (No. 1 and No. 2) for acquiring information related to flaws on the fixing belt, respectively. It is a figure for demonstrating how to obtain | require the flaw depth of a fixing belt. FIG. 28A and FIG. 28 are diagrams (No. 3 and No. 4) for acquiring information related to flaws on the fixing belt, respectively. FIG. 11 is a diagram (No. 5) for acquiring information related to a flaw of the fixing belt. It is a figure for demonstrating the further another example of operation | movement of a surface information detection apparatus. FIGS. 31A and 31B are diagrams (No. 6 and No. 7) for acquiring information related to flaws on the fixing belt. FIGS. 32A and 32B are views (No. 1 and No. 2) for explaining an arrangement example of the reflection type optical sensor, respectively. FIG. 33A and FIG. 33B are diagrams for explaining the movement operation of the reflective optical sensor. FIGS. 34A and 34B are views (No. 1 and No. 2) for explaining the light spot (horizontal light spot) of Comparative Example 1, respectively. FIGS. 35A and 35B are diagrams (No. 1 and No. 2) for explaining the light spots of Comparative Example 2, respectively. FIG. 36A and FIG. 36B are diagrams (No. 1 and No. 2) for explaining the light spot (vertically long light spot) of Example 1, respectively. FIGS. 37A and 37B are diagrams for explaining a method of acquiring information regarding a flaw on the fixing belt using two reflective optical sensors in the second embodiment. FIG. 38A and FIG. 38B are diagrams for explaining a method of acquiring information related to flaws on the fixing belt using a single reflective optical sensor in the third embodiment. FIG. 39A is a diagram for explaining the light spot group of the fourth embodiment, and FIG. 39B is a diagram for explaining the rectangular light spot of the fifth embodiment. FIG. 40A is a diagram (part 1) showing a positional relationship between a plurality of horizontally long light spots formed side by side in the Y-axis direction and scratches on the fixing belt in Comparative Example 3, and FIG. FIG. 10 is a diagram (part 1) illustrating a positional relationship between a plurality of vertically long light spots formed side by side in the Y-axis direction and scratches on the fixing belt in Example 6. 41A is a diagram (part 2) showing the positional relationship between a plurality of horizontally long light spots formed side by side in the Y-axis direction and scratches on the fixing belt in Comparative Example 3, and FIG. FIG. 12 is a diagram (part 2) illustrating a positional relationship between a plurality of vertically long light spots formed side by side in the Y-axis direction and scratches on the fixing belt in Example 6. FIG. 13 is a third diagram illustrating the positional relationship between a plurality of vertically long light spots formed side by side in the Y-axis direction and flaws on the fixing belt in Example 6. FIG. 43A is a diagram illustrating a state in which a plurality of vertically long light spots are arranged in the Y-axis direction by the reflective optical sensor positioned at the first position in Example 7, and FIG. FIG. 10 is a diagram showing a state in which a plurality of vertically long light spots are arranged in the Y-axis direction by a reflective optical sensor located at a second position shifted from the first position in the Y-axis direction in Example 7. In Example 7, it is a figure for demonstrating the case where the reflection type optical sensor containing a small number of light emission parts is moved, and several vertical light spots are formed. 45A and 45B are views (No. 1 and No. 2) for explaining the surface polishing apparatus, respectively.

  Hereinafter, an embodiment of the present invention will be described. FIG. 1A schematically shows a configuration of a color printer 100 as an example of the image forming apparatus of the present invention. The image forming apparatus of the present invention is not limited to a color printer, but can be implemented as a monochrome printer, a monochrome copying machine, a color copying machine, a facsimile machine, a plotter apparatus, or an MFP that combines these functions. Needless to say. Hereinafter, description will be made by appropriately using the XYZ three-dimensional orthogonal coordinate system shown in FIG.

  As can be seen from FIG. 1A, the color printer 100 is a so-called “tandem printer”. A transfer belt 11 that is an intermediate transfer member and denoted by reference numeral 11 in FIG. 1A is an endless belt, and is wound around a plurality of rollers (here, three rollers) whose axial direction is the Y-axis direction. It is driven by a driving roller which is one of the plurality of rollers, and rotates in one direction around the Y axis (here, counterclockwise when viewed from the −Y side). As used below, “clockwise” and “counterclockwise” mean the direction of rotation about the Y axis as viewed from the −Y side.

  A portion on the −Z side of the transfer belt 11 is stretched so as to be parallel to the XY plane, and four image forming units UY, UM, UC, and UB are spaced apart from each other in the X-axis direction. ing. Here, “Y, M, C, B” in the code represents each color of “yellow, magenta, cyan, black”, the image forming unit UY is a unit that forms a yellow image, and the image forming unit UM is A unit for creating a magenta image, an image creation unit UC is a unit for creating a cyan image, and an image creation unit UB is a unit for creating a black image.

  On the −Z side of the four image forming units UY to UB, an optical scanning device 13 (exposure device) which is an “image writing device” is arranged, and a cassette 15 is further arranged on the −Z side.

  Since the four image forming units UY to UB have substantially the same configuration, the image forming unit UY will be described briefly with reference to FIG.

  An image forming unit UY shown in FIG. 1B includes a photoconductor drum 20Y as a photoconductive photoconductor (image carrier), a charger 30Y and a developing unit 40Y disposed around the photoconductor drum 20Y. And a transfer roller 50Y and a cleaning unit 60Y. Note that “rectangles indicated by broken lines” in FIG. 1B collectively indicate the units of the image forming unit UY, and do not necessarily indicate an entity such as a casing.

  The charger 30Y is a “contact type charging roller”. An area between the charger 30Y and the developing unit 40Y is set as an image writing unit using the scanning light LY.

  The photosensitive drum 20 </ b> Y is disposed on the −Z side of the −Z side portion of the transfer belt 11 and is in contact with the surface of the transfer belt 11.

  The transfer roller 50 </ b> Y is disposed on the opposite side of the −Z side portion of the transfer belt 11 from the photosensitive drum 20 </ b> Y and is in contact with the back surface of the transfer belt 11. That is, the transfer belt 11 is held in the Z-axis direction by the photosensitive drum 20Y and the transfer roller 50Y.

  The three image forming units UM to UB have the same configuration as that of the image forming unit UY. Regarding these components, the photosensitive drums 20M to 20B, the chargers 30M to 30B, and the developing units 40M to 40M 40B, transfer rollers 50M to 50B, and cleaning units 60M to 60B.

  Such a color image printing process by the color printer 100 is relatively well known, and will be briefly described below.

  When the color image forming process starts, the photosensitive drums 20Y to 20B and the transfer belt 11 start to rotate (circulate). The rotation of the photosensitive drums 20Y to 20B is clockwise, and the rotation of the transfer belt 11 is counterclockwise.

  The photosensitive surfaces (scanned surfaces) of the four photosensitive drums 20Y to 20B are uniformly charged by the corresponding four chargers 30Y to 30B. The optical scanning device 13 performs image writing on the photosensitive surfaces of the four photosensitive drums 20Y to 20B by optical scanning with the corresponding four scanning lights LY to LB.

  Various types of optical scanning devices 13 that perform such image writing have been well known in the past. As the optical scanning device 13, these known devices are appropriately used.

  The photosensitive drum 20Y is optically scanned using a laser beam whose intensity is modulated according to the yellow image as the scanning light LY, and the yellow image is written to form an electrostatic latent image corresponding to the yellow image. .

  The formed electrostatic latent image is a so-called negative latent image, and is visualized as a “yellow toner image” by reversal development using yellow toner by the developing unit 40Y.

  The visualized yellow toner image is electrostatically primarily transferred onto the surface side of the transfer belt 11 by the transfer roller 50Y.

  The photosensitive drum 20M is optically scanned using a laser beam whose intensity is modulated in accordance with the magenta image as the scanning light LM, and the magenta image is written, and an electrostatic latent image (negative latent image) corresponding to the magenta image is written. ) Is formed.

  The formed electrostatic latent image is visualized as a “magenta toner image” by reversal development using magenta toner by the developing unit 40M.

  The photosensitive drum 20C is optically scanned using a laser beam whose intensity is modulated according to the cyan image as the scanning light LC, and the cyan image is written, and an electrostatic latent image (negative latent image) corresponding to the cyan image is written. ) Is formed.

  The formed electrostatic latent image is visualized as a “cyan toner image” by reversal development using cyan toner by the developing unit 40C.

  The photosensitive drum 20B is optically scanned using a laser beam whose intensity is modulated in accordance with the black image as the scanning light LB, the black image is written, and an electrostatic latent image (negative latent image) corresponding to the black image is written. ) Is formed.

  The formed electrostatic latent image is visualized as a “black toner image” by reversal development using black toner by the developing unit 40B.

  The magenta toner image is electrostatically primarily transferred to the transfer belt 11 side by the transfer roller 50M. At this time, the magenta toner image is superimposed on the “yellow toner image previously transferred” on the transfer belt 11.

  Similarly, the cyan toner image is primarily transferred onto the transfer belt 11 by the transfer roller 50C so as to be superimposed on the “yellow toner image and magenta toner image that have been previously superimposed and transferred”. The black toner image is primarily transferred to the yellow, magenta, and cyan color toner images on the transfer belt 11 by the transfer roller 50B.

  In this way, four color toner images of yellow, magenta, cyan, and black are superimposed on the transfer belt 11 to form a “color toner image”.

  The four photosensitive drums 20Y to 20B are cleaned by the corresponding four cleaning units 60Y to 60B after the toner image is transferred, and residual toner and paper dust are removed.

  The color toner image formed on the transfer belt 11 in this way is electrostatically “secondary transferred from the transfer belt 11 onto the recording sheet S (transfer material) as a sheet-like recording medium by the secondary transfer roller 17. The image is fixed on the recording paper S by the fixing device 19 and discharged out of the printer.

  The recording sheet S is stacked and accommodated in the cassette 15, is fed by a well-known paper feeding mechanism (not shown), waits in a state where a pointed portion is held by a timing roller (also called a registration roller) not shown, and is transferred. The color toner image on the belt 11 is sent to the secondary transfer unit in synchronization with the movement.

  The secondary transfer portion is a contact portion between the transfer belt 11 and the secondary transfer roller 17 that rotates in contact with the transfer belt 11, and the timing at which the color toner image on the transfer belt 11 reaches the secondary transfer portion. In addition, the recording sheet S is sent to the secondary transfer portion by the timing roller.

  Thus, the color toner image and the recording paper S are superimposed, and the color toner image is electrostatically transferred onto the recording paper S.

  The recording sheet S on which the color toner image has been transferred by the secondary transfer is subsequently fixed on the color toner image when passing through the fixing device 19, and then discharged onto the tray TR on the upper side of the color printer 100.

  The above is a schematic description of the “color image printing process” by the color printer 100.

  Next, the fixing device 19 in the color printer 100 shown in FIG. 1A will be described with reference to FIG.

  The fixing device 19 employs a so-called “belt fixing method” as can be seen from FIG. 1C, and includes a fixing belt 61 as a fixing member, a heating roller 62, a fixing roller 64, a pressure roller 63, a tension roller 65, It has a peeling claw 66 and the like.

  The fixing belt 61 has a “release layer made of PFA, PTFE, etc.” on a base material such as nickel or polyimide, and “elasticity such as silicon rubber” between the base material and the release layer. It is the structure which provided the layer.

  That is, the surface of the fixing belt 61 is “resin such as PFA or PTFE that forms a release layer”, and information on the surface is a detection target.

  The fixing belt 61 is an endless belt, is wound around a heating roller 62 and a fixing roller 64, and “necessary tension” is given by a tension roller 65.

  The heating roller 62 is a hollow roller made of, for example, a metal or an alloy such as aluminum or iron, and incorporates a heat source H such as a halogen heater. Heat from the heat source H is transmitted to the fixing belt 61 through the heating roller 62, and the fixing belt 61 is heated. Although not shown, a temperature sensor (such as a thermopile) for detecting the surface temperature of the fixing belt 61 is provided on the surface of the fixing belt 61 in a non-contact manner. A contact temperature sensor (thermistor) that contacts the fixing belt 61 can also be used.

  The fixing roller 64 is made of, for example, a metal or alloy metal core such as aluminum or iron surrounded by silicon rubber to give elasticity. The fixing roller 64 drives the fixing belt 61 to rotate counterclockwise.

  The pressure roller 63 is provided with an elastic layer such as silicon rubber on a metal or alloy core metal such as aluminum or iron, and the surface layer is composed of a release layer such as PFA or PTFE.

  The pressure roller 63 is in pressure contact with a portion of the fixing belt 61 that is wound around the fixing roller 64. This pressure contact deforms the fixing roller 64 to form a nip portion. This nip portion becomes a fixing portion.

  The tension roller 65 is formed by providing silicon rubber on a metal or alloy core metal such as aluminum or iron.

  A plurality of peeling claws 66 are arranged apart from each other in the axial direction (Y-axis direction) of the fixing roller 64 so that the pointed portion thereof is in contact with the surface of the fixing belt 61.

  When fixing is performed, when the fixing belt 61 rotates counterclockwise while being heated by the heater H, and the pressure roller 63 rotates clockwise, and the surface temperature of the fixing belt 61 reaches a fixable temperature, the color toner image is displayed. Is transferred in the direction of the large arrow in FIG. 1A and enters the fixing portion (nip portion).

  The color toner image receives heat from the fixing belt 61 side in the fixing unit, is pressed against the fixing belt 61 by the pressure roller 63, receives pressure, and is fixed on the recording paper S.

  Supplementally, the color printer 100 has a cleaning device (not shown) for cleaning the transfer belt 11.

  This cleaning device is arranged so as to contact the transfer belt 11 on the −X side of the image forming unit UY in FIG. 1A so as to face the portion of the transfer belt 11 wound around the −X side roller. A cleaning brush and a cleaning blade are provided, and the transfer belt 11 is cleaned by scraping and removing foreign matters such as residual toner and paper dust on the transfer belt 11 with the cleaning brush and the cleaning blade. It has become.

  The cleaning device also has a discharging means (not shown) for carrying out and discarding the residual toner removed from the transfer belt 11.

  In the color printer 100 shown in FIG. 1, as described above, the color toner images formed on the photosensitive drums 20 </ b> Y to 20 </ b> B are sequentially superimposed and transferred to the transfer belt 11 as described above. Although the color toner image is batch-transferred onto the recording paper S by the secondary transfer roller 17, the present invention is not limited to this.

  For example, the recording paper S is carried on the transfer belt 11 and conveyed, and the recording paper S is brought into contact with each photosensitive drum so that the toner images of the respective colors are directly superimposed on the recording paper S and transferred. It is also possible to do. Also in this case, the fixing of the color toner image may be the same as described above.

  Here, in the color printer 100 shown in FIG. 1, the fixing device 19 further includes a surface information detection device 500 that detects surface information of the fixing belt 61.

  The surface information detection apparatus 500 includes a reflective optical sensor 200, a processing apparatus 300, a temperature sensor 400, and the like.

  As shown in FIG. 1C, the reflective optical sensor 200 is disposed to face a portion of the fixing belt 61 wound around the heating roller 62, and the recording paper S is conveyed on the surface of the portion. A plurality of lights arranged in a direction (here, the Y-axis direction) orthogonal to (here, the Z-axis direction) are irradiated in time series, for example, and the reflected light from the surface is received, and an output corresponding to the amount of received light A signal (detection signal) is sent to the processing device 300.

  The width direction of the fixing belt 61 corresponds to the “main scanning direction” in the optical scanning (image writing) by the optical scanning device 13, that is, the longitudinal direction (Y-axis direction) of each photosensitive drum. It is also called “scanning-compatible direction”. The “sub-scanning direction” at the time of optical scanning (image writing) by the optical scanning device 13, that is, the direction corresponding to the rotation direction of each photosensitive drum is also referred to as “sub-scanning corresponding direction”.

  The processing device 300 receives the detection signal (output signal) from the reflective optical sensor 200 and detects the surface state of the fixing belt 61 as surface information. Here, the processing apparatus 300 is disposed in the housing of the color printer 100.

  The temperature sensor 400 measures the temperature of the reflective optical sensor 200 in the housing of the color printer 100 and outputs the measurement result to the processing device 300. The temperature sensor 400 may be either a contact type temperature sensor provided in contact with the reflective optical sensor 200 or a non-contact type temperature sensor provided in a non-contact manner on the reflective optical sensor 200.

  The contact-type temperature sensor is a method of measuring by directly contacting an object, and has a simple structure and is widely used. Main examples include silver temperature measuring resistors, thermistors, thermocouples, IC temperature sensors that use transistor temperature characteristics, and crystal thermometers that use crystal Y-cuts.

  The non-contact temperature sensor is a method of measuring infrared rays emitted from an object and measuring the temperature from the amount of infrared rays. The main types are thermal types such as thermopiles and thermistors that use temperature changes of sensor elements that receive infrared rays, and quantum types such as photodiodes and phototransistors that use changes of sensor elements that receive photons.

  By the way, although the surface of the fixing belt 61 is initially intact (when not used), as the fixing operation is repeated (with an increase in the number of uses), “scratches” due to contact with the peeling claw 66 and the like, “Striped scratches” due to sliding with the edge of the recording paper S and “offset” in which the toner adhering to the recording paper S is transferred to the surface of the fixing belt are generated. When toner is transferred from the preceding recording sheet S to the fixing belt, the succeeding recording sheet S is soiled by the transferred toner.

  Such “the state of the surface of the fixing belt 61 in which scratches and offset have occurred”, that is, “the presence / absence and degree of offset, the state and position of the scratches” is the surface state, and information on the surface state is “surface information”. is there.

  Hereinafter, detection of the surface information of the fixing belt 61 for “streak-like scratches” will be mainly described.

  FIG. 2 is a diagram for explaining fixing by the fixing device 19. A color toner image is transferred onto the recording paper S shown in FIG.

  Here, the recording sheet S is “A4 size” and can be conveyed in a direction parallel to the longitudinal direction or a direction parallel to the short side direction (width direction). 2 indicates the paper width when the A4-sized recording paper S is conveyed in the direction parallel to the longitudinal direction, and the reference A4L in FIG. 2 indicates the direction in which the A4-sized recording paper S is parallel to the lateral direction. The paper width when transporting is shown.

  Since the paper width A4L is substantially equal to the width of the fixing belt 61 (the length in the Y-axis direction), when the A4-sized recording paper S is conveyed in a direction parallel to the short side direction, the paper width A4L is at the end in the width direction of the fixing belt 61. The resulting streak scarcely matters in practice.

  On the other hand, the paper width A4T is shorter than the width of the fixing belt 61, and the streak-like scratches are generated inside the paper width A4L. Therefore, the toner image transferred onto the recording paper S may be unevenly fixed due to the scratches. .

  Reference numerals W1 and W2 in FIG. 2 denote main scanning-corresponding directions (Y-axis direction) at the edge of the recording paper S with respect to the fixing belt 61 when the A4-sized recording paper S is conveyed in a direction parallel to the longitudinal direction. ) Shows the deviation width.

  That is, when the A4 size recording sheet S is conveyed in parallel with the longitudinal direction, the position in the main scanning corresponding direction with respect to the fixing belt 61 cannot be completely matched between the recording sheets S. The passing position of the direction end portion is slightly shifted (varied) between the recording sheets S in the main scanning corresponding direction.

  Further, when a so-called “belt shift” occurs in the fixing belt 61 itself, the surface of the fixing belt 61 is shifted (varied) in the main scanning correspondence direction with respect to the recording sheet S.

  The deviation widths W1 and W2 take this deviation (variation) into consideration.

  In addition, when the deviation width (variation width) of the position where the recording paper S contacts the fixing belt 61 is narrow, streak-like scratches are also concentrated in a narrow range. The transport position in the main scanning corresponding direction may be shifted intentionally.

  The deviation widths W1 and W2 are also considered in such a case. However, the displacement width is about “10 mm” at most.

  Therefore, in consideration of the deviation widths W1 and W2, when the A4 size recording paper S is conveyed in a direction parallel to the longitudinal direction, if the presence / absence of a streak is detected as surface information, the reflective optical sensor The detection range for the main scanning corresponding direction 200 needs to be set larger than the shift widths W1 and W2.

  As shown in FIG. 2, the detection range A related to the main scanning corresponding direction (Y-axis direction) of the reflective optical sensor 200 is set so as to include the shift width W2 out of the shift widths W1 and W2. It is not set on one side. It is considered that the occurrence of a streak is likely to occur in a similar manner in the region of the shift width W1 and the region of the shift width W2, and detection within one shift width is sufficient for practical use. It is possible.

  Of course, a detection range may be set for each of the deviation widths W1 and W2, and further, the detection range may be set to extend over the entire width of the fixing belt 61.

  Therefore, the reflective optical sensor 200 irradiates, for example, a plurality of lights arranged in the main scanning corresponding direction (Y-axis direction) to the detection area 61S that is an area included in the detection range A of the fixing belt 61, for example, in time series.

  As described above, the reflection type optical sensor 200 can detect the detection area 61S that is long in the main scanning corresponding direction of the fixing belt 61. The “relative positional relationship in the corresponding direction” may be relatively rough.

  The processing apparatus 300 can detect the surface state of the detection area 61 </ b> S of the fixing belt 61 by receiving the detection signal (output signal) from the reflective optical sensor 200.

  Then, when the short direction end of the recording paper S is included in the detection range A, the processing apparatus 300 “scratch level”, which is information on a line-shaped flaw formed by the short direction end of the recording paper S. And / or “scratch position (position in the main scanning direction)” is quantified as surface information of the fixing belt 61. This point will be described later.

  Here, the scratch level refers to “degree of scratch”, that is, “scratch depth (roughness) and scratch width (size)”.

  Here, the “scratch depth” will be supplemented.

  When “scratches (scratches due to contact with the thermistor or peeling claw 66 or streak-like scratches)” occur on the surface of the fixing belt 61, as described above, the toner image is formed with the fixing belt 61 at the scratched portion. The contact pressure with the recording paper S becomes weak, “fixing failure” occurs according to the scratches, and “image abnormality” called “white spot (a phenomenon in which image density decreases)” occurs in the fixed image.

  “Scratch depth” in the present specification is a parameter that represents the degree of image abnormality by quantitatively grasping such “correlation between scratch and image abnormality caused by the wound”. .

  Next, the reflective optical sensor 200 will be described. FIG. 3A shows an XY sectional view (No. 1) of the reflective optical sensor 200. FIG. 3B shows an XZ sectional view of the irradiation system of the reflective optical sensor 200. FIG. 4 shows an XY sectional view (No. 2) of the reflective optical sensor 200.

  In FIGS. 3A to 4, reference numeral 61 </ b> S indicates a detection area of the fixing belt 61.

  As an example, the reflective optical sensor 200 includes a plurality of (for example, four) LEDs 211 (light-emitting diodes) arranged in the Y-axis direction (main scanning facing direction), as shown in FIGS. It includes a plurality of (for example, P) LED groups, a lens unit LU, a plurality of PDs 212 (photodiodes), an opening, and the like.

  As an example, a plurality of (for example, P) LED groups are arrayed (mounted) at equal intervals in the Y-axis direction on the surface of the substrate 210 on the + X side, as shown in FIG. Hereinafter, the q-th LED 211 counted from the -Y side in the p-th LED group counted from the -Y side of the plurality of LED groups will be referred to as LED 211-pq. If the total number of LEDs 211 is N, N = 4P. The N LEDs 211 are denoted by reference numerals 211-1-1, 211-1-2, 211-1-3, 211-1-4, 211-2-1,..., 211-2-4,. , 211-pq,... 211-P-4. In general, the value of N is several tens to several hundreds, but can be changed as appropriate.

  As shown in FIGS. 3A and 3B, the lens unit LU includes a lens array LA including a plurality of (for example, P) irradiation lenses 220 and a light receiving lens 220C.

  The lens array LA and the light receiving lens 220C are integrally formed by resin molding, for example.

  A plurality of (for example, P) irradiation lenses 220 individually correspond to a plurality of (for example, P) LED groups, and are disposed on the optical path of light from the corresponding plurality of LED groups. More specifically, the respective irradiation lenses 220 are arranged at equal intervals in the Y-axis direction on the + X side of the substrate 210 so as to face a plurality of (for example, four) LEDs 211 of the corresponding LED group. Furthermore, the optical axis of each irradiation lens 220 is located between the LED 211-p-2 and the LED 211-p-3 of the corresponding LED group. In other words, the LED 211-p-1 and the LED 211-p-2 of each LED group are located on the −Y side of the optical axis of the corresponding irradiation lens 220, and the LED 211-p-3 and the LED 211 of each LED group. −p−4 is located on the + Y side of the optical axis of the corresponding irradiation lens 220. Here, in order to distinguish the P irradiation lenses 220 from each other, the reference numerals 220-1, 220-2,..., 220-p,. P-1) and 220-P.

  Therefore, the light emitted from each LED 211 of each LED group is collected by the corresponding irradiation lens 220 and irradiated to the detection area 61S of the fixing belt 61. As a result, a plurality (N) of light spots S1 to SN (N = 4P) are formed in the detected region 61S so as to be aligned in the Y-axis direction (see FIG. 3A).

  Thus, each LED group and the irradiation lens 220 corresponding to the LED group constitute an irradiation system for irradiating the fixing belt 61 with light. That is, the reflective optical sensor 200 irradiates the fixing belt 61 with light from a plurality of (for example, P) irradiation systems.

  As shown in FIG. 4, the light receiving lens 220 </ b> C is disposed on the optical path of light that is irradiated from each irradiation system onto the detection area 61 </ b> S of the fixing belt 61 and reflected by the detection area 61 </ b> S. Here, the light receiving lens 220C is a “single cylindrical lens”, and is disposed on the + Z side of the lens array LA and the + X side of the substrate 210 (see FIG. 3B). The light receiving lens 220C has a positive power only in the Z-axis direction.

  A plurality (for example, N) of PDs 212 are mounted side by side at equal intervals in the Y-axis direction on the + Z side of a plurality (for example, N) of LEDs 211 on the + X side surface of the substrate 210 (see FIG. 5). Specifically, the N PDs 212 individually correspond to the N LEDs 211, and each PD 212 is irradiated from at least the corresponding LED 211 to the detection area 61S of the fixing belt 61 and reflected by the detection area 61S for light reception. It arrange | positions on the optical path of the light through the lens 220C. 4 and 5, in order to distinguish the N PDs 212 from each other, reference numerals 212-1, 212-2,..., 212- (N−1), 212− N. Hereinafter, the n-th PD 212 counted from the −Y side will be referred to as PD 212-n. Here, n = 4 (p−1) + q is established.

  As described above, the plurality of (for example, N) PDs 212 and the light receiving lens 220 </ b> C constitute a light receiving system that receives the light irradiated to the fixing belt 61 from each irradiation system and reflected by the fixing belt 61. In other words, the reflection type optical sensor 200 receives the light irradiated to the fixing belt 61 from each irradiation system and reflected by the fixing belt 61 by the light receiving system.

  3A, reference numerals 230-0, 230-1,... 230-p,..., 230-N mainly shield flare light between two irradiation systems adjacent in the Y-axis direction. Therefore, a plate-shaped light shielding plate 230 parallel to the XZ plane is shown.

  Also, reference numerals 231-1 and 231-2 shown in FIG. 3B are plate-like shapes parallel to the XY plane for mainly shielding flare light between the LED 211-n and the PD 212-n. A light shielding plate 231 is shown.

  In FIG. 6A and FIG. 6B, as an example, eight light shielding plates 230 (230-0 to 230-7) and two light shielding plates 231 (231-231) when p = 7. 1, 231-2) is shown as an integrated body.

  In this opening, as can be seen from FIG. 6B, eight light shielding plates 230 (230-0 to 230-7) arranged in the Y-axis direction are opposed to each other in the Z-axis direction. 231-2. That is, the opening is formed with seven openings arranged in the Y-axis direction, which individually correspond to the seven irradiation systems. That is, each opening is located between the four LEDs 211 and the irradiation lens 220 of the corresponding irradiation system.

  With the opening configured in this manner, light from an arbitrary LED 211 to be lit is transmitted through the irradiation lens 220 or the light receiving lens 220C other than the corresponding irradiation lens 220 and irradiated to the fixing belt 61. Directly reflected light from the lens surface of the irradiation lens 220 other than the irradiation lens 220 corresponding to the arbitrary LED 211 to be lit or the lens surface of the irradiation lens 220 corresponding to the arbitrary LED to be lit (hereinafter referred to as these lights) (Referred to as flare light) is prevented from directly entering the PD 212.

  Reference numeral 240 in FIGS. 3A and 3B denotes a frame-shaped member whose both ends in the X-axis direction are open ends. The lens unit LU is bonded to the opening end on the + X side of the frame-shaped member 240, and the substrate 210 is bonded to the opening end on the −X side of the frame-shaped member 240. That is, the lens unit LU, the frame-like member 240, and the substrate 210 form a single case as a whole.

  Here, the case and the opening are integrated by resin molding.

  In the reflective optical sensor 200 configured as described above, when the LED 211 -pq is turned on, the emitted “divergent light beam” is emitted to the irradiation lens 220 -p corresponding to the LED 211 -pq. And a light spot is formed in the detection area 61S on the surface of the fixing belt 61.

  As shown in FIG. 4, the reflected light at the “portion where the light spot is formed” in the detection area 61 </ b> S is condensed only in the Z-axis direction by the light receiving lens 220 </ b> C and enters a plurality of PDs 212.

  Here, the reflection of light on the surface of the fixing belt 61 is not specular reflection, and the reflected light from the fixing belt 61 is not condensed in the Y-axis direction by the light receiving lens 220C. The reflected light is received by a plurality of PDs 212 including “PD212-n”.

  Next, the operation of the surface information detection apparatus 500 will be described with reference to the flowchart of FIG. In the surface information detection apparatus 500, the reflective optical sensor 200 is controlled by the processing apparatus 300.

  In the first step Q1, 1 is set to p.

  In the next step Q2, 4 is set to q.

  In the next step Q3, the LED 211-pq is turned on. At this time, the detection region 61S is irradiated with light by an irradiation system including the LEDs 211-pq and the irradiation lens 220-p.

  In the next step Q4, in synchronization with the lighting of the LEDs 211-pq, the reflected light from the detection region 61S is collected only in the Z-axis direction by the light receiving lens 220C, that is, a plurality of PDs 212 including the PD 212-n, Light is received by PD212- (nm) to PD212- (n + m). As described above, n = 4 (p−1) + q.

  Here, to simplify the description, the number of PDs 212 that receive light is “odd”, that is, m is an integer and 2m + 1.

  In this case, the reflected light when the LED 211-pq is turned on is received by the PD 212-n and the m PDs 212 arranged on both sides thereof.

  For example, if m = 2, the plurality of PDs 212 that receive the reflected light are five PDs 212, that is, PD 212-n-2, PD 212-n-1, PD 212-n, PD 212-n + 1, PD 212-n + 2. is there.

  The value of m may be other than 2. What is necessary is just to experimentally obtain the correlation with the image in advance and select a good m. However, when m is small (for example, m = 0), there is only one PD output value, and the detection variation becomes large because the value is small. In addition, when m is large enough to correspond to the sum of PDs, the contrast of the streak-like wound to be detected is lowered. Good m is about 2-6.

  In the next step Q5, the LED 211-pq is turned off.

  In the next step Q6, the detection signal of each PD 212 is sent to the processing device 300. Specifically, each PD 212 photoelectrically converts the amount of received light. The photoelectrically converted signal is amplified and becomes a “detection signal”. The detection signal of each PD is sent to the processing device 300 every time it is detected.

  In the next step Q7, it is determined whether q> 1. If the determination in step Q7 is affirmative, the process proceeds to step Q8. On the other hand, if the determination in step Q7 is negative, the process proceeds to step Q9.

  In step Q8, q is decremented. When step Q8 is executed, the flow returns to step Q3.

  In step Q9, it is determined whether p <P. If the determination in step Q9 is affirmed, the process proceeds to step Q10. On the other hand, if the determination in step Q9 is negative, the process proceeds to step Q11.

  In step Q10, p is incremented. When step Q10 is executed, the flow returns to step Q2.

  That is, the N LEDs 211 scan each of the detected areas 61S of the fixing belt 61 from the left end S-1 to the right end SN (see FIG. 3A) with light, and each LED group (p = 1). To P), the LED 211-p-4 to the LED 211-p-1 are sequentially turned on and off one by one. This is so-called “sequential lighting”.

  When the sequential lighting is repeated, p = P, q = 1, and the final LED 211-P-1 is “lighted / extinguished”, this is sequentially turned on, that is, the measurement for one cycle is completed.

  In step Q11, it is determined whether or not to measure another period. For example, when the detection accuracy needs to be increased, the determination in step Q11 is affirmed. In other words, the detection accuracy can be improved by performing sequential lighting over a plurality of cycles and performing an average value processing of detection results in each cycle. If the determination in step Q11 is affirmed, the flow returns to step Q1. On the other hand, if the determination in step Q11 is negative, the flow ends.

  Therefore, in the color printer 100, for example, the optical scanning device 13 as an image writing device is controlled based on the detection result of the processing device 300 in order to improve the image quality.

  Specifically, after the determination in step Q11 is denied, the optical scanning device 13 is controlled based on the position of the flaw, that is, the detection result in the processing device 300. Specifically, the light emission amount of the light source of the optical scanning device 13 is adjusted according to the scanning timing in the main scanning direction on each photosensitive drum, that is, the position in the main scanning direction.

  More specifically, for example, the amount of light emitted from the light source is set to a normal size at a scanning timing corresponding to a position where the fixing belt 61 is not damaged, and larger than normal at a scanning timing corresponding to a position where the fixing belt 61 is damaged. To do. As a result, the exposure amount (toner adhesion amount) at a position corresponding to the position where the fixing belt 61 is scratched on each photosensitive drum becomes larger than the exposure amount (toner adhesion amount) at other positions, and as a result. The toner image is fixed uniformly on the recording paper S via the fixing device 19. That is, the image quality is improved.

  Further, the optical scanning device 13 may be controlled based on the position and depth of the scratch. Specifically, it is preferable that the light emission amount of the light source is increased (the toner adhesion amount is increased) as the depth of the scratch is deeper.

  Further, the optical scanning device 13 may be controlled based on the position, depth, and width of the scratch. Specifically, it is preferable that the longer the scratch width is, the longer the time for increasing the amount of light emitted from the light source (increasing the amount of toner adhesion).

  Here, when the light spot is in S-1 or S-2 near the end of the detected region 61S on the -Y side, that is, when the LED 211-1 or the LED 211-2 is lit, the irradiation lens 220 is Since it is an inverted magnification system, the number of PDs 212 that receive light is less than five. The same applies to the case where the light spot is at S− (N−1) or S−N near the + Y side end of the detected region 61S.

  Therefore, instead of setting the number of LEDs 211 to be sequentially turned on to N, the light spot on the detected region 61S is, for example, two LEDs 211 near the end on the −Y side and two LEDs 211 near the end on the + Y side. It is also possible to sequentially turn on the remaining N-4 pieces, for example, without sequentially turning on the lights.

  That is, it is not always necessary to use all N LEDs 211 to be turned on / off, and any N ′ (≦ N) of them may be used.

  FIGS. 8A and 8B show experimental results when the reflective optical sensor 200 is operated according to the flowchart of FIG.

  8A shows, for example, a state in which light from the reflective optical sensor 200 is not incident on the fixing belt 61 or a state in which reflected light from the fixing belt 61 is not incident on the reflective optical sensor 200, that is, from the surface information detection device 500. PD212-n (n = 1 to 2) when the LED 211-pq (p = 4, q = 1 to 4) is turned on in a state where it can be considered that the fixing belt 61 as a detection target does not exist. 28) shows the PD output value.

  In this case, the PD output is ideally zero, but as can be seen from FIG. 8A, a mountain-shaped PD output is obtained centering on PD14 (PD212-14) and PD15 (PD212-15). You can see that

  In FIG. 8B, the PD output acquired when the light shielding member 600 shown in FIG. 8A is located at the shielding position is subtracted from the PD output obtained when the light shielding member 600 is located at the retracted position. The PD output at this time, that is, the PD output of only the reflected light from the fixing belt 61 is shown.

  When attention is paid to the peak of the peak of the PD output shown in FIG. 8B, the LEDs 211-p-4, LED 211-p-3, LED 211-p-2, and LED 211-p-1 are sequentially turned on in this order. In this case, it can be seen that the PD number at which the PD output reaches a peak shifts from smaller to larger. This is because when the LED 211-p-4, the LED 211-p-3, the LED 211-p-2, and the LED 211-p-1 are sequentially lit in this order, the detected area 61S of the fixing belt 61 is exposed from the -Y side by light. It is clear from the fact that scanning is performed to the + Y side.

  When the inventors investigated the cause of this mountain-shaped PD output, as shown in FIG. 8B, when the LED 211-pq (p = 4, q = 1-4) is turned on, A part of the divergent light flux passes through the opening end on the −X side (LED 211-pq side) of the opening corresponding to the LED 211-pq in the opening, that is, the opening corresponding to the LED 211-pq. The light shielding plate 230- (p-1), the light shielding plate 230-p, the light shielding plate 231-1, and the light shielding plate 231-2 are reflected and scattered by the respective surfaces on the -X side and received by a plurality of PDs 212. Ascertained (see FIG. 9). In other words, the aperture allows a portion including the principal ray of light from each LED 211 to pass through the corresponding opening, and blocks (reflects) a peripheral portion (flare light) of the portion including the principal ray of the light.

  Therefore, in the present embodiment, as an example, a light shielding member 600 (see FIGS. 22A and 22B) for shielding light emitted from the reflective optical sensor 200 as necessary is provided. .

  More specifically, the light shielding member 600 includes an actuator (not shown) or a manual operation between a shielding position that is a position on the optical path between the reflective optical sensor 200 and the fixing belt 61 and a retreat position that retreats from the shielding position. (See FIGS. 22A and 22B). The light shielding member 600 is moved between the shielding position and the retracted position as necessary by the processing apparatus 300, for example.

  Here, when the light shielding member 600 is located at the retracted position, that is, when the light from the reflective optical sensor 200 enters the fixing belt 61 and the reflected light from the fixing belt 61 enters the reflective optical sensor 200. In other words, in addition to the reflected light from the fixing belt 61 which is the detection target, the PD output of the reflected light from the opening is detected.

  Therefore, the aperture is irradiated with light from each irradiation system in a state where the light shielding member 600 is positioned at the shielding position, and PD output is detected, and the light irradiation member 600 is moved from each irradiation system in a state where the light shielding member 600 is in the retracted position. By irradiating the opening and the fixing belt 61 with light, detecting the PD output, and obtaining the difference between these detection results, it is possible to obtain the PD output of only the reflected light from the fixing belt 61.

  Hereinafter, an example of a surface information detection method for the fixing belt 61 using the surface information detection apparatus 500 will be described.

  Here, the reflective optical sensor 200 and the glass plate as the reference reflector can be opposed to each other (see FIGS. 20A to 21B), and the optical path between the reflective optical sensor 200 and the glass plate. Can be shielded by a light shielding member (not shown). Since the glass plate reflects light on both sides, it is preferable that the glass plate be processed or treated so that it can be reflected only on one side. Specifically, it is desirable that the glass plate be roughened on one side (scattering surface) and further black coated so that it can be reflected only on one side.

  In FIG. 10A, the LED 211 from the LED 211-2-4 to the LED 211-6-1 in a state where the light shielding member is positioned on the optical path between the reflective optical sensor 200 and the glass plate, that is, 28 pieces of light. 28 PD outputs when 20 LEDs 211 among the LEDs 211 are sequentially turned on are shown.

  In FIG. 10B, the LED 211 from the LED 211-2-4 to the LED 211-6-1 in a state where the light shielding member is located at a position off the optical path between the reflective optical sensor 200 and the glass plate. That is, from the 28 PD outputs when the 20 LEDs 211 among the 28 LEDs 211 are sequentially turned on, the 28 PD outputs shown in FIG. A PD output with only reflected light is shown.

  The measured value (measurement result) at the temperature sensor 400 when the measured value (PD output) of FIGS. 10A and 10B is obtained, that is, the temperature of the reflective optical sensor 200 is 25 ° C. Met.

  11A and 11B show PD outputs corresponding to FIGS. 10A and 10B obtained when the measurement result by the temperature sensor 400 is 70.degree. Has been.

  From FIGS. 10A to 11B, it can be seen that when the temperature is 70 ° C., the amount of light emitted from the LED is decreased and the PD output is decreased as compared to when the temperature is 25 ° C.

  FIG. 12 shows the sum of the plurality of PD outputs for each LED shown in FIGS. 10B and 11B, that is, the light received from the LEDs and reflected by the glass plate at the plurality of PDs. A sum of quantities (PD output) (hereinafter also referred to as PD output sum) is shown.

  Here, the sum total of all 28 PD outputs may be obtained, or the sum of an arbitrary number of PD outputs including the maximum value may be obtained. Since this depends on the optical system of the reflective optical sensor 200, it may be determined in advance through experiments or the like. Here, the sum of 13 peripheral PD outputs including the maximum value was obtained.

  That is, FIG. 12 represents the variation (light amount variation) of the light emission amount of each LED at 25 ° C. and 70 ° C. with reference to the glass plate as the reference reflector.

  Here, the glass plate as the reference reflector is used as a reference common to a plurality of reflective optical sensors 200 to be mass-produced.

  Therefore, it can be said that the difference in the graph of FIG. 12 among the plurality of reflective optical sensors 200 represents the individual difference of the reflective optical sensors 200. Therefore, by correcting the light amount variation including individual differences, it becomes possible to compare the output levels of a plurality of reflective optical sensors 200 that are mass-produced with reference to a common reference. That is, the numerical value of each LED shown in FIG. 12 can be used as a light quantity variation correction coefficient for correcting the light quantity variation of each LED in the initial (initial state).

  The movement of the glass plate may be performed manually or automatically using an actuator. Further, the reflective optical sensor 200 may be configured to be movable with respect to the glass plate.

  Moreover, it may replace with a glass plate and may use the member which has the characteristic and function equivalent to this as a reference | standard reflector.

  Moreover, instead of the glass plate, for example, an unused fixing belt 61 may be used as the reference reflector. However, in the case where the fixing belt 61 is used as a reference reflector, the fixing belt 61 that is a component of the actual machine (color printer 100) may be used as it is, but a reference reflector need not be separately prepared. There are concerns such as deformation in the environment. On the other hand, in the case of a glass plate, there are many advantages when used as a reference, such as stability over time and environment and surface uniformity.

  Here, “when the fixing belt 61 is in an unused state” is “before the start of use of the color printer 100”, for example, before the manufacture of the color printer 100, at the time of manufacture, or before the start of printing after manufacture.

  When the reference reflector is used as an unused fixing belt 61, the opening member and the unused fixing belt 61 from each irradiation system in a state where the light shielding member 600 is positioned at the retracted position before the use of the color printer 100 is started. Irradiating light to detect the PD output (the former), and irradiating the opening body with light from each irradiation system with the light shielding member 600 positioned at the shielding position to detect the PD output (the latter), The difference between the former and the latter can be taken. As a result, it is possible to obtain a PD output of only the reflected light from the unused fixing belt 61 as a reference reflector.

  FIG. 13A shows a plurality of temperature environments when a glass plate is used as a reference reflector (for example, the temperature of the reflective optical sensor 200 is 25 ° C., 40 ° C., 50 ° C., 60 ° C., 70 ° C., 80 ° C. Variation in the amount of light of each LED in a temperature environment that becomes a reference when a glass plate is used as a reference reflector (for example, a temperature environment in which the temperature of the reflective optical sensor 200 is 25 ° C.). The value obtained by dividing the LED light quantity variation (see FIG. 12), that is, the temperature coefficient of each LED light quantity variation in a plurality of temperature environments (change rate with respect to temperature change from the reference temperature (25 ° C.)) It is shown. FIG. 13B is a graph in which the graph of FIG. 13A is rewritten with the horizontal axis representing temperature.

  As can be seen from FIGS. 13A and 13B, even if the variation in the amount of light of each LED at 25 ° C. is corrected, the PD output sum for each LED varies as the temperature of the reflective optical sensor 200 increases. I can see it coming. This is because the amount of light emitted from each LED changes linearly with respect to temperature, and the temperature coefficient varies from LED to LED and further from temperature to temperature.

  Therefore, the measurement is performed in the plurality of temperature environments, and the light quantity variation of each LED when the temperature of the reflective optical sensor 200 is the reference temperature (for example, 25 ° C.) and the temperature coefficient of each LED in the plurality of temperature environments. Is preferably stored in a memory 300a (eg, flash memory, DRAM, SRAM, ROM, universal memory, etc.) of the processing device 300. Note that another storage medium such as a hard disk may be used instead of the memory 300a.

  Then, the PD output sum of only the reflected light from the fixing belt 61 for each LED is acquired, the temperature at the time of acquisition is measured by the temperature sensor 400, and the measured value and the reference temperature (for example, 25 ° C.) stored in the memory 300a. ) To calculate the light amount variation correction coefficient in each temperature environment using the light amount variation (light amount variation correction coefficient) of each LED and the temperature coefficient of each LED in a plurality of temperature environments, and the calculated light amount variation correction coefficient If the obtained PD output sum for each LED is corrected, the surface state of the fixing belt 61 can be accurately detected regardless of the temperature at the time of detection.

  FIG. 14 shows a result of correcting the sum of the PD outputs for the LED when the reference reflector is irradiated with light from the LED in a plurality of temperature environments (the above six temperature environments) using this correction method. ing. From FIG. 14, it can be seen that almost the same result is obtained regardless of the temperature environment, and the variation in the light emission quantity of each LED due to the temperature change can be sufficiently corrected.

  Further, FIG. 15 shows a result of detecting the surface state of the fixing belt 61 after the start of use of the color printer 100 by using this correction method (PD output sum based only on the reflected light from the fixing belt 61 for each LED). It is shown. FIG. 15 shows that the degree of scratches at the position on the fixing belt 61 where the light spot by the LED 211-3-3 is formed can be detected with high accuracy.

  In the above description, the variation in the amount of light emitted from the LED accompanying a change in temperature is corrected. However, originally, the variation in the amount of emitted light from the LED accompanying a change with time, the temperature change or change with time of the light receiving sensitivity of the PD, optical Needless to say, correction should be performed in consideration of changes in the characteristics of the entire reflective optical sensor 200 including changes in system temperature and changes over time.

  Actually, it has been found that the change in the light receiving sensitivity of the PD is sufficiently smaller than the change in the light emission amount of the LED, and the influence of the characteristic change (change in the optical characteristic) on the temperature change of the optical system is sufficiently small. Therefore, the change in the amount of light emitted from the LED is taken up as a main factor of the change in the reflective optical sensor 200. However, in terms of measurement, the reflective optical sensor 200 is regarded as a PD output value that reflects the influence of changes in the characteristics of the LED, optical system, and PD. This indicates a change in the amount of light.

  Next, a specific procedure of the surface information detection method for the fixing belt 61 using the surface information detection apparatus 500 will be described with reference to the flowcharts shown in FIGS. 16 and 17.

  First, a series of processes before the start of use of the color printer 100 will be described with reference to FIG. Here, an unused fixing belt 61 is used as the reference reflector. The light shielding member 600 is initially located at the retracted position.

  In the first step J1, 1 is set to n.

  In the next step J2, the temperature of the reflective optical sensor 200 is set to the nth temperature (1 ≦ n ≦ N). Specifically, for example, by adjusting the temperature of the heat source H of the heating roller 62, the temperature of the reflective optical sensor 200 can be set to an arbitrary temperature of, for example, 25 ° C. to 80 ° C. The temperature setting here is performed while monitoring the measurement value of the temperature sensor 400. Here, 25 ° C. is the first temperature, 40 ° C. is the second temperature, 50 ° C. is the third temperature, 60 ° C. is the fourth temperature, 70 ° C. is the fifth temperature, and 80 ° C. is the sixth temperature. That is, N = 6. Note that the temperature setting of the reflective optical sensor 200 may be performed by a heat source other than the heating roller 62. N is not limited to 6 and may be 2 or more. The temperature range is not limited to 25 ° C to 80 ° C. The first to Nth temperatures can also be changed as appropriate.

  In the next step J3, the light shielding member 600 is positioned at the shielding position.

  Then, according to the procedure of the flowchart shown in FIG. 7, the plurality of LEDs 211 are sequentially turned on (step J4), and the PD output 1 for each PD corresponding to the lighting of each LED is obtained (step J5). The acquired PD output is stored in the memory 300a of the processing device 300.

  In the next step J6, the light shielding member 600 is positioned at the retracted position. Then, the plurality of LEDs 211 are sequentially turned on in the procedure of the flowchart shown in FIG. 7 (step J7), and the PD output 2 for each PD corresponding to the lighting of each LED is acquired (step J8).

  In the next step J9, the light shielding member 600 is positioned at the shielding position. Here, the light shielding member 600 is not necessarily located at the shielding position, but it can be expected that the reflective optical sensor 200 is protected from heat and dust by being located at the shielding position. That is, it is preferable to place the light shielding member 600 at the shielding position except when the fixing belt 61 is irradiated with light.

  In the next step J10, the PD output difference is acquired. Specifically, PD output 2 for each PD with respect to lighting of each LED 2 -PD output 1 (PD output difference for each PD) is obtained. That is, the PD output 1 is detected in a state where the light shielding member 600 is located at the shielding position, the PD output 2 is detected in a state where the light shielding member 600 is located in the retracted position, and the difference between the two is obtained, thereby obtaining the reference reflection. It becomes possible to obtain a PD output for each PD by only reflected light from the unused fixing belt 61 as a body.

  In the next step J11, an nth light quantity variation correction coefficient that is a light quantity variation of each LED at the nth temperature is calculated. The nth light quantity variation correction coefficient is a sum of PD output differences (PD output sums) for each PD with respect to each LED at the nth temperature.

  In the next step J12, the nth temperature coefficient is calculated. The nth temperature coefficient is obtained by dividing the nth light quantity variation correction coefficient by the first light quantity variation correction coefficient that is the light quantity variation of each LED at the first temperature.

  In the next step J13, it is determined whether or not n is smaller than N. If the determination in step J13 is affirmed, the process proceeds to step J14. On the other hand, if the determination in step J13 is negative, the process proceeds to step J15.

  In step J14, n is incremented. When step J14 is executed, the process returns to step J2.

  In this way, a series of operations are performed at each set temperature, and the light quantity variation correction coefficient and the temperature coefficient at the set temperature are calculated.

  In step J15, the first light quantity variation correction coefficient, the first to Nth temperature coefficients, and the measured values (first to Nth temperatures) of the temperature sensor 400 are stored in the memory 300a of the processing apparatus 300 in a tabulated state. Instead of the first to Nth temperature coefficients, the second to Nth light quantity variation correction coefficients may be stored in the memory 300a.

  Here, when a reference reflector other than the fixing belt 61 in an unused state (for example, a glass plate) is used, the reference reflector is a predetermined position between the reflective optical sensor 200 and the fixing belt 61 and the predetermined position. (See FIGS. 20A and 20B), the surface information detecting device 500, the reflective optical sensor 200 may be attached to the fixing belt 61. You may comprise so that a movement between the position which opposes and the position where the reflection type optical sensor 200 opposes a reference | standard reflector is possible (refer FIG. 21 (A) and FIG. 21 (B)).

  For example, when a glass plate is used as the reference reflector, a step (step) of positioning the glass plate between the reflective optical sensor 200 and the fixing belt 61 or the reflective optical sensor 200 before step J7. It is necessary to perform a step (step) for positioning the substrate at a position facing the glass plate.

  Next, a series of processes performed at an arbitrary timing after the start of use of the color printer 100 will be described with reference to FIG. Here, for example, a glass plate is used as the reference reflector. The light shielding member 600 is initially located at the retracted position.

  Note that “after the start of use of the color printer 100” means that image formation (printing) including a fixing operation by the fixing device 19 has been performed at least once. The arbitrary timing can be set at a time when a predetermined number of printed sheets elapses, for example, every 1000 sheets. Note that, if the job is stopped during printing, the productivity is lowered. Therefore, it is preferable to perform the job after the completion of the predetermined number of printings.

  In the first step U1, the light shielding member 600 is positioned at the shielding position.

  Then, the plurality of LEDs 211 are sequentially turned on in the procedure of the flowchart shown in FIG. 7 (step U2), and the PD output 3 for each PD corresponding to the lighting of each LED is acquired (step U3).

  In the next step U4, the light shielding member 600 is positioned at the retracted position.

  Then, the plurality of LEDs 211 are sequentially turned on in the procedure of the flowchart shown in FIG. 7 (step U5), and the PD output 4 for each PD corresponding to the lighting of each LED is acquired (step U6).

  In the next step U7, the light shielding member 600 is positioned at the shielding position. Here, the light shielding member 600 is not necessarily positioned at the shielding position, but it can be expected that the reflective optical sensor 200 is protected from heat and dust by being positioned at the shielding position. For this reason, it is preferable that the fixing belt 61 is positioned at the shielding position except when light is irradiated.

  In the next step U8, the acquired PD output difference is acquired. Specifically, PD output 4 for each PD with respect to lighting of each LED 4 -PD output 3 (PD output difference for each PD) is obtained. That is, the PD output is detected in a state where the light shielding member 600 is located at the shielding position, and then the PD output is detected in a state where the light shielding member 600 is located in the retracted position. It becomes possible to obtain a PD output only by the reflected light from 61.

  In the next step U9, the measurement value obtained by the temperature sensor 400 is acquired.

  In the next step U10, the measured values obtained by the temperature sensor 400, the plurality of temperatures (first to Nth temperatures) stored in the memory 300a, the plurality of temperature coefficients corresponding to the plurality of temperatures, and the first Based on the table including the light amount variation correction coefficient, the kth light amount variation correction coefficient is calculated. Specifically, the k-th light amount variation correction coefficient includes the k-th temperature coefficient that is the temperature coefficient of the k-th temperature that is the closest to the measurement value of the temperature sensor 400 in the first to N-th temperature environments, and the first light amount. It is obtained by multiplying by the variation correction coefficient. In Step J15 of the flowchart of FIG. 16, when the second to Nth light quantity variation correction coefficients are stored in the memory 300a instead of the first to Nth temperature coefficients, the first to Nth temperature environments are stored. Of these, the light quantity correction coefficient at the k-th temperature that most closely approximates the measurement value of the temperature sensor 400 may be used as the k-th light quantity variation correction coefficient.

  In the next step U11, the variation in the light amount (the variation in the PD output sum due to only the reflected light from the fixing belt 61) is corrected using the kth light amount variation correction coefficient.

  In the next step U12, the PD output sum based only on the reflected light from the fixing belt 61 for each LED, in which the light quantity variation is corrected, is quantified as the surface information of the fixing belt 61. This quantification method will be described later.

  FIG. 18 shows a light amount variation correction when the series of processes of FIG. 17 is performed at a predetermined timing when the reflective optical sensor 200 is used for a long period of time (the time that the LED deteriorates) after the use of the color printer 100 is started. The PD output sum for each subsequent LED is shown. In this case, the light amount variation is larger than the PD output sum (FIG. 14) for each LED after the light amount variation correction when the series of processing of FIG. 17 is performed when the reflective optical sensor 200 is almost new. Therefore, the detection accuracy of the surface information of the fixing belt 61 is lowered.

  Therefore, for example, a series of processing (step W1 to step W27) shown in the flowchart of FIG. 19 may be performed at the predetermined timing after the start of use of the color printer 100. Steps W1 to W15 in FIG. 19 correspond to Steps J1 to J15 in FIG. 16, and Steps W17 to W27 in FIG. 19 correspond to Steps U2 to U12 in FIG. When Step W17 in FIG. 19 is started, the light shielding member is located at the shielding position (see Step W9).

  However, although not explicitly shown in the flowchart of FIG. 19, a step (step) of making the reflective optical sensor 200 and the glass plate face each other is performed before step W7, and reflection is performed between step W8 and step W17. A step (step) of releasing the facing of the mold optical sensor 200 and the glass plate is performed. This is because the fixing belt 61 may be damaged after the use of the color printer 100 is started, and it is necessary to use a reference reflector other than the fixing belt 61 (for example, a glass plate). In these steps, the glass plate may be moved, or the reflective optical sensor 200 may be moved.

  By performing a series of processes shown in FIG. 19, light amount variation correction is performed in consideration of (reflects) a variation in light emission amount due to a change with time (deterioration with time) as well as a variation in light emission amount due to a temperature change of each LED. Can do.

  Then, after the use of the color printer 100 is started, the series of processing shown in FIG. 19 is periodically performed, so that it is possible to perform light amount variation correction considering (reflecting) the deterioration state and temperature of each LED at the time of detection. The surface information of the fixing belt 61 can be accurately detected regardless of the detection timing.

  In the flowchart of FIG. 19, the series of processes of steps W1 to W15 and the series of processes of steps W17 to W27 are performed continuously, but the present invention is not limited to this. For example, after performing a series of processes of steps W1 to W15, a series of processes of steps W17 to W27 may be performed after a predetermined time has elapsed, or after performing a series of processes of steps W1 to W15, steps W17 to W27 are performed. Only a series of processes may be performed periodically.

  However, after the series of processing of steps W1 to W15 is performed, before the use (printing) of the color printer 100 is performed as much as possible, the series of steps W17 to W27 is preferably performed before the use of the color printer 100 (before printing). It is desirable to perform the process. This is because by performing Steps W17 to W27 before each LED is deteriorated as much as possible after performing Step W15, the variation in the light amount can be accurately corrected, and the surface information of the fixing belt 61 can be detected with high accuracy. In the color printer 100, the inside of the apparatus becomes hot each time printing is performed, and the deterioration of each LED proceeds.

  Further, when acquiring PD output 1, PD output 2, PD output 3, and PD output 4, as shown in the flowchart of FIG. 7, the plurality of LEDs 211 are sequentially turned on for a plurality of cycles, and averaged by the number of cycles. Alternatively, detection accuracy can be improved by using a median for removing abnormal values.

  In addition, it is preferable to sequentially turn on the plurality of LEDs 211 for at least one cycle over the circumference of the fixing belt 61. In this case, it is possible to reduce the influence of the detection error due to the rotation fluctuation of the fixing belt 61. it can. In particular, it is possible to remove abnormal values by sequentially lighting for 5 cycles or more and using data for 3 cycles or more excluding the maximum value and the minimum value.

  Here, the light shielding member 600 will be specifically described. 22A shows a state where the light shielding member 600 is located at the shielding position, and FIG. 22B shows a state where the light shielding member 600 is located at the retracted position. 22A and 22B, the illustration of the fixing belt 61 and the like is omitted.

  Here, the light shielding member 600 can be moved in the Z-axis direction between the shielding position and the retracted position by the actuator 700. The light shielding member 600 is mainly composed of an opaque engineering plastic having high temperature heat resistance, and a black low reflection member (not shown) is attached to the reflective optical sensor 200 side.

  The actuator 700 is automatically operated by the processing device 300 in synchronization with the operation timing of the reflective optical sensor 200. The light shielding member 600 may be manually movable.

  The engineering plastic used for the light shielding member 600 shields the heat from the fixing belt 61 from being directly transferred to the reflective optical sensor 200 when the light shielding member 600 is located at the shielding position, and reduces the heat transfer. It has a function.

  Engineering plastics are also called engineering plastics, and super engineering plastics with particularly high heat resistance may be used. Examples of the black low-reflection member include a thin film and the like, and it has a function of absorbing light from the reflective optical sensor 200 and preventing reflection of incident light to the PD 212. Of course, if the engineering plastic itself has a low reflection function, the black low reflection member may not be provided.

  The length of the light shielding member 600 shown in FIGS. 22A and 22B in the Y-axis direction is, for example, substantially the same as or slightly the entire width of the fixing belt 61 in the Y-axis direction (main scanning corresponding direction). It is formed long and reduces heat transfer from the entire fixing belt 61 to the reflective optical sensor 200.

  On the other hand, as another example of the light shielding member, a light shielding member whose length in the Y-axis direction is shorter than the entire width of the fixing belt 61 in the Y-axis direction and longer than the reflective optical sensor 200 may be used. In this case, direct heat transfer from the portion of the fixing belt 61 facing the reflective optical sensor 200 can be reduced, but heat transfer from the periphery of the portion cannot be reduced, and therefore FIG. 22 (A) and FIG. The effect of reducing heat transfer is smaller than in the case of the light shielding member 600 shown in B). However, if the performance of the reflective optical sensor 200 can be sufficiently ensured, priority is given to downsizing the light shielding member, and this direct reduction in heat transfer may be sufficient. As a result, the installation space for the light shielding member can be reduced, and the size of the color printer 100 can be reduced.

  FIG. 23 shows still another example of the light shielding member. In FIG. 22B, it is necessary to secure a space corresponding to the movable range of the light shielding member 600 in the Z-axis direction. Therefore, as shown in FIG. 23, as an example, a belt-shaped light shielding member 650 may be wound around a rotation axis parallel to the Y axis. That is, the light shielding member 650 can be wound and pulled out by rotating the rotation shaft, for example, by an actuator or manually. As a result, space saving can be achieved. Note that the rotation shaft may be manually rotated or automatically rotated. In FIG. 23, illustration of the fixing belt 61 and the like is omitted.

  Normally, the surface temperature of the fixing belt is set to about several tens of degrees to 200 degrees, so that the heat transfer directly occurs in the reflective optical sensor disposed facing the fixing belt. The reflective optical sensor is composed of, for example, an LED, a PD, a lens, an electronic circuit, a case for housing these, and particularly at a high temperature, such as thermal deformation of the lens and the case, an LED, a PD, an electronic circuit, and the like. There is a problem that performance degradation occurs due to thermal characteristics. Alternatively, in order to ensure sensor performance, there is a problem that components that can withstand high temperatures must be selected, and the reflective optical sensor itself becomes very expensive.

  Further, from the viewpoint of enhancing the dustproof effect of the reflective optical sensor, it is preferable that the light shielding member has a longer length in the main scanning correspondence direction. On the other hand, from the viewpoint of miniaturization, it is preferable that the light shielding member has a short length in the main scanning correspondence direction or can be wound and pulled out as described above.

  Here, in step U12 of FIG. 17 and step W27 of FIG. 19, there are several methods for quantifying the surface state of the fixing belt 61, that is, “scratch level” and / or “scratch position”. An example will be described.

  As described above, when the LEDs 211-pq are sequentially turned on and a detection signal (PD output) for each lighting is sent to the processing device 300, the processing device 300 performs differential processing and light amount variation correction. The surface state of the fixing belt 61 is quantified by the procedure of the flowchart shown in FIG.

  The processing apparatus 300 receives the detection signals of all the PDs 212 (212-1 to 212-N) (in principle, the number of detection signals is (2m + 1) each time one LED is turned on / off). Every time it is received (step G1), the “sum” of (2m + 1) detection signals is calculated, and this is set as “detection result: Rpq” (step G2). In this way, it is possible to obtain the reflected light intensity: Rpq from the surface of each of the plurality of lights sequentially irradiated onto the surface of the fixing belt 61 so as to be separated in the main scanning corresponding direction.

Next, the surface information of the fixing belt 61 is detected based on the detection result: Rpq. In general, when the surface of the fixing belt 61 is scratched, the reflected light from the fixing belt 61 “decreases regular reflection component” and “diffuse reflection component increases” compared to the case where there is no scratch.
In the above-described example, when the LED 211-pq is turned on, if there is a flaw at the position of the irradiated light spot, the specular reflection light component is reduced at this portion, so the PD 212-n receives light. The amount of light decreases, and the amount of received light increases in the surrounding PD212-n-m to PD212-n-1, PD212-n + 1 to PD212-n + m. However, in general, the detection result Rpq corresponding to a site with a wound is reduced as compared with that of a site without a wound.

  Based on such characteristics of the detection signal, “surface presence / absence”, “scratch level”, and “scratch position (position in the main scanning corresponding direction)” as the surface state are quantified as surface information.

  For this purpose, the detection result: Rpq obtained as described above is “differentiated” (step G3). Although there are various methods for the differentiation operation, here, the simplest operation will be described as “the difference between detection results of two adjacent PDs is divided by the arrangement pitch of the PDs”. That is, it is an operation for calculating “the inclination of the detection result of two adjacent PDs”.

  FIG. 25A schematically shows an example of a detection result: Rpq obtained from sequential lighting of a plurality of LEDs 211 for one cycle. In FIG. 25A, 13 data points are drawn, but this is for simplification of illustration, and there is no particular meaning that there are 13 data points.

  In the reflective optical sensor 200, the reflected light intensity can be obtained corresponding to each position in the main scanning corresponding direction on the surface of the fixing belt 61. Therefore, the processing apparatus 300 compares a plurality of reflected light intensities in the main scanning corresponding direction. By doing so, it is possible to determine the presence or absence of scratches on the surface of the fixing belt 61. That is, it can be seen that there is a flaw at the “position where the reflected light intensity is reduced”.

  In FIG. 25 (A), in the vicinity of the center of the detection range A, the value of the detection result: Rpq (the reflected light intensity on the vertical axis) is decreased, and thus “there is a flaw”. I understand. In this manner, “existence of a flaw” is detected as the surface information. If no flaw exists, the flow ends (step G4).

  Next, detection of “scratch position”, that is, step G5 “determination of scratch position” will be described.

  FIG. 25B shows the result of performing the above-described differentiation operation on the detection result data shown in FIG. As is clear from general differential theory, “the differential value is 0” at the minimum position, and “the differential value changes from negative to positive” before and after the minimum position.

  Therefore, as shown in FIG. 25B, the “scratch position” can be detected (determined) by obtaining the “zero cross position where the differential value greatly changes from negative to positive”.

  When the “absolute value of the differential value” is smaller than a predetermined value set in advance, it indicates that “the decrease in reflected light intensity is small”, and it is determined that “there is no flaw”.

  Hereinafter, a specific example (Example) will be described. Here, the reflective optical sensor 200 shown in FIGS. 3A and 3B is configured as follows.

Number of arrays of LEDs 211 and PD 212: N = 24
Sequentially lit LEDs 211: n = 3-22
LED 211, PD212 arrangement pitch: 1mm

  In this reflective optical sensor 200, light spots are irradiated on the surface of the fixing belt 61 at a pitch of 1 mm. Detection results obtained by using the above-described reflective optical sensor 200 on the fixing belt 61 after fixing on 400,000 transfer sheets (A4 size transported in the direction parallel to the longitudinal direction). The relationship between Rpq and the position in the main scanning direction is shown in FIG.

  Since the light spot is irradiated onto the surface of the fixing belt 61 at P = 1 mm, n on the horizontal axis in FIG. 26A is equivalent to the light spot irradiation position expressed in “mm units”.

  FIG. 26B shows a result obtained by differentiating the detection result of FIG. 26A with respect to the main scanning corresponding direction.

  In order to smooth the differential value, “slope at three points of R− (n−1), R−n, and R− (n + 1)” may be calculated.

  When the “zero cross position” in FIG. 26B is obtained, n = 12.5, and the “12.5 mm position” that is the middle of the light spot irradiation positions corresponding to the LED 211-12 and the LED 211-13 is the position of the scratch. Can be detected (determined).

  Next, detection (determination) of the scratch level will be described. The scratch level includes the above-described “scratch depth” and “scratch width”. First, detection of “scratch depth”, that is, determination of the depth of the scratch will be described. Note that the determination of the depth of the flaw is performed as necessary. If not, the flow ends (step G6).

  Qualitatively, it is considered that “the deeper the flaw is, the greater the roughness of the surface of the fixing belt 61 and the greater the decrease in reflected light intensity”. Therefore, in order to detect “scratch depth”, “the amount of decrease in reflected light intensity” is obtained. A schematic diagram thereof is shown in FIG.

  When the detection result: R-n (reflected light intensity) is as shown in FIG. 27, the “detection result: minimum value of R-n” may be simply obtained. It is also conceivable that “the inclination component is superimposed” on the detection result: R−n due to the inclination (attachment accuracy) of the mounting state, the inclination of the fixing belt 61, and the like.

  The “scratch position” can be detected as described above. A position without a flaw is “a detection result: a position where the variation of R−n is small”, that is, a “position where the differential value gathers around 0”. Considering this point, a position without a flaw is calculated from the differential result in the main scanning corresponding direction (step G7).

  Referring to FIG. 28A and FIG. 28B, the position where there is a flaw: the detection result at n0: R-n0 and the detection result at at least two flaws: n1, n2: R- An example of obtaining the “reduction amount of reflected light intensity” from n1 and R-n2 will be described.

  Detection result: In order to subtract the slope component superimposed on Rn, the distance between the "approximate straight line connecting the detection results at a position without a plurality of flaws" and the detection result at a flawed position may be obtained.

  A case will be described in which this method is applied to the results of FIGS. 26A and 26B described above to determine the amount of decrease in reflected light intensity.

  FIG. 28 (A) shows the “position where a plurality of points are collected within a range of ± 20 where the differential value is small” with respect to the position of the scratch from FIG. 26 (B). From FIG. 28A, it is possible to select n = 6 and n = 15 as positions without a flaw.

  Therefore, a position having a flaw: n0 = 12.5, a position having no flaw: n1 = 6, and n2 = 15 are extracted, and the detection result: R−n is used to calculate “depth (roughness) of flaws”. Is calculated (step G8).

  The broken line in FIG. 28B is a “straight line connecting Rn-n1 and Rn-n2”, and the “dashed arrow corresponds to the depth of the flaw”. Here, “scratch depth is 63.1”.

  The “ratio of decrease in reflected light intensity” at the position of the scratch is 0.16 (16%). As described above, “scratch depth” quantitatively captures “correlation between scratches and image abnormalities caused by scratches” and is expressed as a parameter representing the degree of image abnormalities. The depth “63.1” specifies not the “physical depth of the scratch itself” but the “degree of image abnormality (density reduction)” corresponding to this.

  From FIG. 28B, it can be seen that the “scratch depth is superimposed” on the slope component indicated by the broken line.

  As the scratch level (scratch depth) increases, this “decrease in reflected light intensity” increases.

  Detection of “scratch width (size)” as another surface information, that is, determination of the scratch width will be described. Note that the determination of the width of the scratch is performed as necessary (step G9), and if not, the flow ends.

  The center position of the flaw is detected as described above. Therefore, a detection result at a position having a flaw: a position having a reflected light intensity at which “a reduction amount of the reflected light intensity corresponding to the depth (roughness) of the flaw” is reduced by a predetermined amount (for example, 50%) from RN. Is calculated.

  FIG. 29 is an enlarged view of the vertical axis of FIG. From FIG. 29, it is possible to detect (determine) that the “half-width of scratch” is 3 mm (step G10). When step G10 is executed, the flow ends.

  As described above, when a flaw exists, the flaw depth and flaw width, that is, surface information (surface state parameters) may be detected, or only necessary parameters may be determined.

  Hereinafter, the thought process that the inventors have reached this embodiment will be described.

  In the experiment, the inventors have disclosed an LED and an irradiating lens for eliminating light (referred to as flare light) that passes through an irradiating lens other than the irradiating lens corresponding to the LED to be lit and irradiates the fixing belt. Since the opening provided with an opening between the two has a thickness, there has been a problem in that reflected light on the front surface of the opening (LED side surface) is directly incident on the PD.

  That is, when it can be considered that there is no fixing belt as a detection target of the reflection type optical sensor, since there is no light reflected from the fixing belt, the PD output should ideally be zero. However, the PD output does not become zero due to the reflected light at the front surface of the opening. For this reason, when a fixing belt is present, there is a problem in that PD output including the reflected light from the front surface of the opening is detected in addition to the reflected light from the fixing belt to be detected.

  Conversely, the PD output when it can be considered that the fixing belt does not exist does not include the reflected light from the fixing belt, which is the detection target, and is therefore an output proportional to the light emission amount of the LED, and the change in the light emission amount of the LED Focused on being able to use to figure out.

  By the way, when using several LED, it is calculated | required to adjust the emitted light quantity (or light spot light quantity) of each LED equally. Generally, the current value and the resistance value are adjusted so that the light amount of the light spot after passing through the lens is equal at the time of factory shipment (initial), but the deterioration rate of the light emission amount of light with time of each LED is uneven. Therefore, the amount of light emitted by each LED after a predetermined time has elapsed is not equal. In addition, since the temperature dependence of the light emission amount of each LED is also non-uniform, the light emission amount of each LED does not become equal when the temperature in the usage environment changes.

  As described above, if the light emission quantity of each LED is adjusted to be completely equal at the time of factory shipment (initial stage) (if the light quantity variation is zero), there is no effect on the detection accuracy, but this is very costly. It takes.

  Therefore, in order to reduce costs, it is necessary to be applicable even when there is an adjustment error or when adjustment is not performed. For this reason, for example, correction using a light amount variation correction coefficient based on the light amount of the light spot is necessary.

  However, in order to measure the light amount of the light spot, a dedicated measuring device for measurement, such as an optical power meter, is required separately, resulting in an increase in manufacturing equipment costs.

  Therefore, the inventors have proposed a correction method that combines the calculation of the light amount variation correction coefficient before or after the start of use of the color printer and the light amount correction at an arbitrary timing and temperature after the start of use of the color printer. A surface information detection device has been realized that can perform quantitatively equal detection even when a change with time or a change in temperature occurs.

  In particular, when correcting the light quantity variation, a special measurement device is not required by using the light reception result of the light receiving unit (for example, PD) of the sensor itself.

  Further, it is possible to accurately detect streak-like scratches in the conveyance direction of the recording medium caused by contact between the sheet-shaped recording medium and the surface of the fixing belt.

  Furthermore, based on the detection result of the surface information detection device, a signal for notifying that it is time to replace the fixing belt is issued, or the surface condition is improved by the surface condition adjusting means of the fixing belt. An image forming apparatus capable of forming a high-quality image without streaks can be provided.

  The color printer 100 of the present embodiment described above includes an image including the fixing belt 61 for fixing the toner image transferred to the recording paper S, and the surface information detecting device 500 for detecting the surface information of the fixing belt 61. The surface information detection apparatus 500 is a forming apparatus, and includes a reflective optical sensor 200 having an irradiation system and a light receiving system including a plurality of LEDs, a temperature sensor 400 that measures the temperature of the reflective optical sensor 200, and an irradiation system. A first light reception result in the light receiving system for each temperature environment and a first measurement result in the temperature sensor 400 when at least the first irradiation for irradiating the reference reflector with light is performed in a plurality of temperature environments; Based on the second light reception result in the light receiving system and the second measurement result in the temperature sensor 400 when the second irradiation for irradiating at least the fixing belt 61 from the irradiation system is performed. Includes a processing unit 300 for obtaining the surface information of the fixing belt 61, a.

  The surface information detection method of the present embodiment is a surface information detection method for detecting surface information of the fixing belt 61 for fixing the toner image transferred to the recording paper S. In a plurality of temperature environments, a plurality of surface information detection methods are used. At least the reference reflector is irradiated with light from the irradiation system of the reflective optical sensor 200 having the irradiation system including the LED and the light receiving system, and the reflected light is received by the light receiving system and the temperature of the reflective optical sensor 200 is measured. In the first step, the second step of irradiating at least the fixing belt 61 from the irradiation system, receiving the reflected light by the light receiving system and measuring the temperature of the reflective optical sensor 200, and the first step And a step of obtaining surface information of the fixing belt 61 based on the light reception result and the measurement result and the light reception result and the measurement result in the second step.

  In the color printer 100 and the surface information detection method of the present embodiment, the first light reception result and the first measurement result (the light reception result in the first step) reflecting the state of the reflective optical sensor 200 in a plurality of temperature environments. And the measurement result) and the second light reception result and the second measurement result (light reception result and measurement result in the second step) reflecting the surface state of the fixing belt 61 in an arbitrary temperature environment. The surface information of the belt 61 can be obtained.

  More specifically, the light quantity variation correction coefficient for each temperature environment is calculated from the first light reception result and the first measurement result (light reception result and measurement result in the first step) in a plurality of temperature environments, and the second The second light reception result (the light reception result in the second step) can be corrected using the light quantity variation correction coefficient corresponding to the measurement result (the measurement result in the second step).

  As a result, according to the color printer 100 and the surface information detection method of the present embodiment, the surface information of the fixing belt 61 can be detected stably and accurately.

  On the other hand, for example, when the light from the irradiation system is measured using an optical power meter or the like, the cost increases, and data reflecting the characteristics of the light receiving system cannot be acquired.

  Further, for example, in the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2006-251165, since a plurality of photosensors are used, individual variations in the characteristics of the photosensors and mounting variations are likely to occur, and the reflectance measurement is performed. Variations will increase. Furthermore, the temporal change of the light emission amount of the LED and the temperature change are not taken into consideration.

  Further, the reference reflector is the unused fixing belt 61 that is actually used in the color printer 100, thereby detecting the reflected light state and the surface information of the fixing belt 61 when calculating the light quantity variation correction coefficient. In this case, the state of the reflected light can be made the same except for the difference in the surface state of the fixing belt 61 at the time of reflection, and more accurate detection is possible. In addition, the configuration is simple compared to the case where another member is added as the reference reflector, and it does not take time to calculate the light quantity variation correction coefficient and detect the surface information.

  In addition, by using, for example, a glass plate for the reference reflector, the stability over time and the environment is high, and the surface uniformity is also high, so there are many advantages as a reference, and more accurate detection is possible. .

  In addition, the reflective optical sensor 200 is provided with a plurality of openings for individually passing the portions including the principal rays of the light from the plurality of light emitting units LED 211, and reflects the peripheral portion of the portion including the principal rays of the light. Since it has an opening, the flare light from each LED can be shielded by the opening. Further, the aperture can be used as a reference (reference reflector) for correcting variations in the amount of light emitted from each LED 211.

  Further, the surface information detection device 500 includes a shielding position on the optical path between the opening and the fixing belt 61 or on the optical path between the fixing belt 61 and the light receiving system, and a retreating position for retreating from the light shielding position. It further includes a light shielding member 600 that can move between the two.

  In this case, PD output detection with the light shielding member 600 positioned at the shielding position and PD output detection with the light shielding member 600 retracted from the shielding position are possible. It is possible to cancel the PD output component not caused by the fixing belt 61 or calculate the light quantity variation correction coefficient from the PD output detection before and after the start of use of the color printer 100 in a state where the light shielding member 600 is located at the shielding position. Become. The light shielding member 600 also has a function of reducing heat transfer from the fixing belt 61 to the reflective optical sensor 200 and a function of preventing dust and the like from entering the reflective optical sensor 200.

  As a detection result in a plurality of PDs 212, a PV value obtained by subtracting a minimum value from a maximum value (effective in subtracting the influence of electrical noise or the like), a PD output sum in a plurality of PDs 212 (error is reduced), By subtracting the minimum value from the sum of the multiple PD output values near the maximum value (subtracting the effect of electrical noise and reducing the error), etc., it can be selected according to the specifications of the reflective optical sensor 200 for high accuracy. It is possible to calculate a correct light quantity variation correction coefficient.

  The color printer 100 is an image forming apparatus that forms an image on the recording paper S (sheet-like recording medium), and a fixing belt 61 for fixing the toner image formed on the recording paper S to the recording paper S. And the reflective optical sensor 200 of the present embodiment that uses the fixing belt 61 as an object.

  In this case, scratches on the surface of the fixing belt 61 can be detected with high accuracy, and deterioration of image quality can be prevented in advance.

  Conventionally, it was not possible to detect the presence or absence of a flaw while correcting the temperature change or temporal change of the LED, but in this embodiment, the presence or absence of a flaw is quantitatively detected by using a light quantity variation correction coefficient. can do.

  Conventionally, the position of the flaw and the width of the flaw cannot be detected. In the present embodiment, the flaw of the detection area 61S corresponding to the detection range A of the fixing belt 61 is detected from the detection result in the present embodiment. It is possible to detect the position and the width of the scratch.

  Further, as the surface state of the fixing belt 61, it is possible to simultaneously detect the scratch level (scratch depth and scratch width) and the position of the scratch in the main scanning direction. Conventionally, even if the depth of the scratch is known, the width of the scratch related to the size of the recording paper S and the position of the scratch in the main scanning direction cannot be detected.

  Hereinafter, another example of the surface information detection method using the reflective optical sensor 200 (an example simpler than the above embodiment) will be described with reference to the flowchart of FIG.

  Here, based on the specific result shown in FIG. 31A, the surface information of the fixing belt 61 is detected based on the detection result: Rpq.

  In addition, since LED211-pq (p = 2-6, q = 1-4) in FIG. 31 (A) shows Rpq (refer FIG.31 (B)), in FIG. It is read as Rpq.

  In the above embodiment, the “presence / absence of scratch” is first determined, but here the “presence / absence of scratch” is determined last.

  In the first step V1, each PD detection signal is received in the same manner as in step G1 in FIG.

  In the next step V2, the detection result Rpq for the LED 211-pq is calculated in the same manner as in step G2 in FIG.

  In the next step V3, the “scratch position” is determined.

  Specifically, the largest scratch, that is, the position at which the PD output sum at Rpq takes the smallest value is defined as the “scratch position”. FIG. 31B shows that the position of the scratch is R-4-3.

  In the next step V4, a position without a flaw is calculated. The position without a flaw is a position where the left and right sides of FIG. 31B are searched for the flaw position R-4-3, and the PD output sum takes the second largest value. From FIG. 31B, it is R-3-2 on the left side and R-5-4 on the right side.

  Here, one reason for not taking the largest value is shown. Assuming that there is one flaw and both ends of the flaw are positions where there is no flaw, the value is ideally constant (see FIG. 25A). However, since it actually includes variations in measurement such as variations in the fixing belt 61 and variations in the reflective optical sensor 200, some abnormal value may be included. For this reason, the second largest value is taken with the meaning of the abnormal value removal.

  In the next step V5, “scratch depth” is determined. The depth of the scratch corresponds to a value obtained by subtracting the PD output sum of R-4-3 from the average value of the PD output sum of R-3-2 and R-5-4.

  As described above, “scratch depth” quantitatively captures “correlation between scratches and image abnormalities caused by scratches” and is expressed as a parameter representing the degree of image abnormalities. This is not the “depth”, but the “degree of image abnormality (density reduction)” corresponding to this. By using this “scratch depth”, “the presence or absence of a scratch” is determined (step V6).

  Here, the correlation between the depth of the flaw and the image abnormality is grasped in advance by experiments or the like, and the depth of the flaw to be determined as having a flaw is set. By comparing this set value with the depth of the detected flaw, it is determined that there is a flaw if the detected flaw depth is greater than or equal to the set value, and if it is less than that, it is determined that there is no flaw.

  In the reflective optical sensor 200 of the above embodiment, the plurality of LEDs 211 are “sequentially lit”, but the plurality of LEDs 211 may be lit simultaneously. In this case, the plurality of PDs 212 also receive the reflected light in synchronization with the simultaneous lighting timing.

  In this case, the surface information detection apparatus adopts “the detection content of the PD 212-n corresponding to the LED 211-pq as the detection result: Rpq without taking the sum of the detection signals of the PD 212 as described above. .

  That is, the reflected light intensity can be obtained in correspondence with each light spot irradiated in the main scanning corresponding direction, in other words, “each position in the main scanning corresponding direction on the surface of the fixing belt 61”.

  The form of the reflective optical sensor is not limited to the reflective optical sensor 200 of the above embodiment.

  The point is that the surface of the fixing belt 61 may be “a configuration that can irradiate a plurality of light spots separated in the main scanning direction and receive the reflected light”.

  Incidentally, the reflective optical sensor 200 described in the above embodiment uses a reflective optical sensor that irradiates the surface of the fixing belt 61 with a plurality of light spots in the main scanning direction and receives the reflected light. The detection range A including the end can be reduced by disposing it at a position facing the vicinity of the end of the size sheet. That is, the reflective optical sensor 200 can be downsized. Further, the reflection-type optical sensor 200 is, for example, in a direction orthogonal to the transport direction when transporting a small size (for example, A4 size) paper in a direction parallel to the longitudinal direction in the main scanning corresponding direction on the surface of the fixing belt 61. Can be placed relatively rough on one side.

  Even if the length of the detection range A in the main scanning correspondence direction is shortened by installing the reflective optical sensor 200 at a location facing the vicinity of the end in the direction orthogonal to the conveyance direction of the recording paper S, the paper width edge Can be included in the detection range A. The fact that the detection range A can be shortened has the advantage that the reflective optical sensor 200 can be reduced in size particularly in the main scanning direction.

  Since the “scratch width” is about several hundred μm to several mm and the fluctuating position variation range is about several mm, the detection range A has a size of “about 5 mm to 15 mm in the main scanning corresponding direction”. Is preferred.

  In the color printer 100, for example, “a plurality of sizes of transfer sheets” such as A3 size, A4 size, and A5 size can be used.

  In general, the largest transfer paper (recording paper S) that can be passed is A3 size, and this is often conveyed in a direction parallel to the longitudinal direction. As the “small paper width”, The detection of surface information due to “streak-like scratches” using transfer paper of a size other than A3 size is an object.

  If the recording paper S of A2 size or larger can be passed in the longitudinal direction, the surface information due to the streak of the recording paper S having a size other than the size of the recording paper S is a detection target. .

  In the above embodiment, one reflection type optical sensor 200 is installed. For example, one reflection type optical sensor 200 is provided at a position facing both ends in a direction orthogonal to the conveyance direction of the A4 size recording paper S. A total of two can be arranged. Further, a larger number of reflective optical sensors 200 can be arranged so as to support transfer papers of a plurality of sizes.

  However, as described above, the occurrence of streak-like scratches occurs in substantially the same manner at both ends in the width direction of the recording paper, and no significant difference is seen in the scratch level. It is.

  Further, for example, in the image forming apparatus such as the color printer 100, the surface state of substantially the entire region of the fixing belt 61 in the main scanning corresponding direction can be detected so that the reflective optical sensor 200 can cope with various paper sizes. good.

  For example, in the case of an image forming apparatus capable of A1 portrait paper, it contacts both ends in the width direction of A2 size, A3 size, A4 size, A5 size, B3 size, B4 size, B5 size, and B6 size paper. The reflective optical sensor is designed to be long in the direction corresponding to the main scanning so that the surface state of the fixing belt 61 can be detected by the reflective optical sensor.

  That is, the length of the reflective optical sensor can correspond to various paper sizes (recording media of various sizes) with respect to the arrangement direction of the plurality of irradiation lenses of the reflective optical sensor (here, the main scanning corresponding direction). By making the size sufficiently large, it is possible to prevent undetected scratches appearing at different locations on the fixing belt 61 depending on the paper size.

  If one reflection type optical sensor 200 is provided, the surface information of the fixing belt 61 can be obtained without being affected by “characteristic variation or mounting variation of the reflection type optical sensor 200” that occurs when a plurality of reflection type optical sensors 200 are used. It can be detected well.

  In the above embodiment, the “arrangement of a plurality of light spots” irradiated by the reflective optical sensor 200 is the “main scanning correspondence direction” orthogonal to the conveyance direction of the recording paper S (FIG. 32A). However, the arrangement of the light spots indicated by the reference sign S-P in FIG. 3 is not limited to this. In short, the arrangement of the plurality of light spots only needs to intersect the transport direction.

  FIG. 32B is an example of “when the arrangement of the light spots SP intersects the transport direction”, and shows a state inclined by 45 degrees with respect to the transport direction (Y direction). In this case, the detection range A ′ in the direction corresponding to the main scanning is “1 / √2” of the detection range A, which is shortened. However, the arrangement pitch of the light spots in the direction corresponding to the main scanning can also be reduced to 1 / √2. The resulting position resolution can be improved.

  Further, in the above embodiment, the surface information due to “striated scratches” in the fixing belt 61 is the main detection target. However, the detection target is not limited to this, and the above-described offset or “contact with the thermistor or the peeling claw” is not limited thereto. It may be a "scratch caused".

  For example, in the case of offset, when the state of the toner fixed on the surface of the fixing belt 61 is “film-like”, the decrease in reflected light intensity: Rpq as a detection result is “relatively small and wide range”. It can be detected from such characteristics.

  Further, as described above, the width of the “scratches caused by contact with the thermistor or the peeling nail” is “several tens μm to several hundreds μm”, whereas the “scratch width” is about several hundred μm to several mm as described above. Since the occurrence position is almost determined, it can be distinguished from the “streak-like wound” by the detection position and the width of the wound.

  In the above embodiment, the case where the “fixing belt” is used as the fixing member has been described. However, the fixing member is not limited to this, and it is needless to say that, for example, a fixing roller can be used.

  When a fixing belt is used as the fixing member, the “fixing belt using a material having a high surface hardness such as PFA as the surface layer” is easily damaged as the fixing belt, and detection of surface information is important. By detecting surface information using 200, management such as belt replacement becomes easy.

  Further, the surface information on the surface of the fixing member is related to “striped scratches along the recording medium conveyance direction, which are generated by contact (sliding) between the sheet-like recording medium and the surface of the fixing member, as in the above embodiment. In this case, as the surface information, it is possible to simultaneously detect the scratch level (scratch depth and scratch width) and the position of the scratch in the main scanning correspondence direction.

  In addition, when the surface information on the surface of the fixing member is information related to the scratch level and the position of the flaw of a streak, as described above, the position of the flaw is detected with respect to a plurality of detection results: Rpq. The inflection point (valley value) of the detection result can be calculated with high accuracy by specifying the differential operation in the arrangement direction of the plurality of light spots, and the position of the flaw can be calculated with high accuracy.

  Further, as described above, the scratch level is determined from the detection result at the position of the scratch and the detection result at at least two positions where the absolute value of the differential value, which is the result of the differential operation on the plurality of detection results, gathers near zero. By doing so, the detection result at a position without a flaw is also used, so that the flaw level can be accurately calculated by “removing the superimposed inclination component”.

  In addition, by irradiating a plurality of light spots on the surface of the fixing belt “sequentially spaced apart in a direction crossing the conveyance direction”, crosstalk (when viewed from one PD, a plurality of light spots is compared). In other words, it is possible to improve the detection accuracy of the detection result obtained corresponding to each light spot position in the main scanning corresponding direction.

  The reflective optical sensor has N (≧ 1) LEDs arranged in one direction, and M (N ≧ M ≧) that collects light from each of the N LEDs as a light spot on the surface of the fixing member. 1) A lens array including one condenser lens and K (≧ 1) photosensors that receive reflected light on the surface of the fixing member in each light spot may be used.

  In this case, a plurality of LEDs correspond to one condenser lens, and the structure of the lens array is simplified. Further, by reducing the number of photosensors, electronic components such as operational amplifiers can be reduced, which is advantageous in terms of cost. Furthermore, the photosensor may have a single light receiving surface. The condensing lens can be made to function as a light receiving lens that guides reflected light to the photosensor by increasing the size.

  In the above embodiment, before and after the start of use of the color printer 100, the LED 211 from the LED 211-2-4 to the LED 211-6-1 with the light shielding member 600 positioned at the shielding position, that is, of the 28 LEDs 211. Although the 28 PD outputs when the 20 LEDs 211 are sequentially turned on are used, it is possible to calculate the light quantity variation correction coefficient even when the light shielding member 600 is located at the retracted position.

  However, when the degree of scratching on the fixing belt 61 is inferior, it is affected by that portion, and the accuracy of the calculated light quantity variation correction coefficient is reduced. For this reason, it is preferable to acquire the detection results of the plurality of PDs 212 in a state that does not include the reflected light from the fixing belt 61, that is, in a state where the light shielding member 600 is positioned at the shielding position.

  33 (A) and 33 (B) show an example in which the reflective optical sensor 200 is movable with respect to the fixing belt 61 in FIG. 1 (C). The reflective optical sensor 200 can be moved by an actuator. As this actuator, for example, any one of a moving stage, a rotating stage, a solenoid mechanism, a feed screw mechanism, a linear motor device, a cylinder device and the like may be used.

  More specifically, as shown in FIG. 33A, the reflective optical sensor 200 may be movable between a facing position facing the fixing belt 61 and a retracted position retracted from the facing position. In this case, a reference reflector (for example, plate glass) may be disposed on the optical path of the light from the reflective optical sensor 200 located at the retracted position.

  In addition, as shown in FIG. 33B, the reflective optical sensor 200 may be rotatably provided between a position facing the fixing belt 61 side and a position facing the reference reflector (for example, plate glass) side. good.

  As a result, since the position of the reflective optical sensor 200 can be changed between a position where the fixing belt 61 is irradiated with light and a position where the fixing belt 61 is not irradiated, the light shielding member 600 is provided as compared with the case where the light shielding member 600 is moved by an actuator. There is no need, and the number of parts can be reduced.

  In the above embodiment, the reflective optical sensor 200 has a configuration in which the LED and the PD correspond one-to-one. However, the present invention is not limited to this. For example, the laser beam is deflected by an optical deflector and the fixing belt is used. It may have a configuration in which reflected light from the surface of 61 is received by at least one PD, and a reflective optical sensor including one LED and one PD is moved in the main scanning-corresponding direction by driving means. You may have the structure to make.

  Incidentally, as in Comparative Example 1 shown in FIG. 34A, the width of the light spot in the Z-axis direction (hereinafter also referred to as the sub-direction) that is the moving direction of the fixing belt 61 is the moving direction of the fixing belt 61. When the width of the light spot is equal to or less than the width of the light spot in the Y-axis direction (hereinafter also referred to as the main direction), that is, the light spot is horizontally long or the light spot is horizontally long (the main direction is the longitudinal direction). In the case where the light spot is formed on the vertical streak of the fixing belt 61, the smaller the width of the scratch relative to the width of the light spot in the main direction, the smaller the portion of the light spot (scratched portion). The ratio of the occupancy decreases (see FIG. 34B), and the accuracy of detecting the state of the flaw is reduced. This is because the difference in detection value between the case where a scratched part and a non-scratched part (parts other than the scratched part) are mixed in the light spot and the case where only the non-scratched part is present in the light spot is reduced. .

  In order to increase the ratio of scratches in the light spot, it is conceivable to reduce the light spot as in Comparative Example 2 shown in FIGS. 35 (A) and 35 (B). In order to reduce the light spot, it is necessary to reduce the magnification of the irradiation optical system that guides the light from the light emitting part to the fixing belt, or to reduce the area of the light emitting part (for example, LED).

  However, if the distance between the light emitting part and the irradiating lens is increased in order to reduce the magnification of the irradiation optical system, the light use efficiency is reduced (side effect 1). Further, if the distance between the light emitting unit and the fixing belt is shortened in order to reduce the magnification of the irradiation optical system, the output of the reflective optical sensor is reduced, deteriorated, or damaged due to the temperature rise (side effect 2).

  In addition, reducing the area of the light emitting section also leads to a decrease in output, increasing the SN ratio and decreasing the detection accuracy.

  Therefore, as in the first embodiment shown in FIG. 36A, the width of the light spot in the sub direction may be made wider than the width in the main direction. That is, the shape of the light spot as the irradiation region may be set to be vertically long (the sub direction is the longitudinal direction). Here, the “irradiation area” means an area irradiated with light from one light emitting unit of the reflective optical sensor. In the first exemplary embodiment, when the reflective optical sensor includes a plurality of light emitting units, a plurality of irradiation areas are formed on the fixing belt 61. In the first embodiment, the shape of the light spot is, for example, an ellipse whose longitudinal direction is the sub direction.

  Since the formation of the vertically elongated light spot can be realized by making the width of the light emitting portion in the sub direction wider than the width of the main direction (for example, making the shape of the light emitting portion an ellipse having the sub direction as the longitudinal direction), Without reducing the magnification of the irradiation optical system or reducing the area of the light emitting part (without the side effects 1 and 2), the ratio of the wound part in the light spot can be improved, The state detection accuracy can be improved. As a result, it is possible to accurately determine the influence of scratches on the fixing belt 61 on the image.

  In addition, as a method for making the irradiation region vertically long, in addition to the method of widening the width of the light emitting unit in the sub direction more than the width of the main direction, for example, the sub direction from the light emitting unit having the same width in the main direction There is also a method of condensing light having a cross-sectional shape having the same width in the main direction with a lens having a condensing power in the main direction larger than that in the sub direction.

  Here, as one method for determining the state of the vertical streak-like scratches on the fixing belt 61, as in the second embodiment shown in FIGS. A position facing a portion where a vertical streak flaw occurs (a portion that contacts the end of the recording paper in the Y-axis direction) and a portion where a flaw-like flaw occurs in the fixing belt 61 (the Y direction of the recording paper) Reflective optical sensors 1 and 2, which are reflective optical sensors of Example 1, are respectively installed at positions facing each other at a position that is not in contact with the end of the optical sensor 1 and output signals of the reflective optical sensors 1 and 2. A method of determining the influence of the scratch on the image quality by comparing (detection value) can be considered.

  Further, as in the third embodiment shown in FIGS. 38A and 38B, detection is performed while the reflective optical sensor of the first embodiment is moved in the main direction, and a vertical streak in the fixing belt 61 is detected. An output signal (detected value) when the reflective optical sensor is located at a position facing the position where the occurrence of the occurrence of the occurrence of a vertical streak, and a position where the reflective optical sensor is located at a position facing the position where the vertical streak-like scratch does not occur. It is conceivable to determine the effect of the scratch on the image quality by comparing the output signal (detection value) when the image is detected. Here, among the detection values of the reflective optical sensor, the minimum value may be adopted as a detection value for a spot where a scratch occurs, and the maximum value may be adopted as a detection value for a spot where no scratch occurs.

  According to the second and third embodiments, even when the position of the scratch is shifted in the main direction, the detection result of the scratch and the non-scratch portion in the light spot is used to influence the scratch on the fixing belt 61 on the image. It can be determined with high accuracy.

  In the first embodiment, the shape of the light spot is vertically long (the sub-direction is the longitudinal direction). Instead of this, a plurality of light spots are formed, for example, as in the fourth embodiment shown in FIG. A light spot group may be formed by arranging the light spots in the sub-direction, and a vertically long irradiation region may be configured as a whole (as viewed macroscopically). This can be realized by using a light source (light emitting unit group) in which a plurality of light emitting units are arranged in a direction parallel to the sub direction.

  In this case, if the sum of the areas of the scratches in the plurality of light spots is larger than the sum of the areas of the non-scratch parts, it is possible to improve the detection accuracy of the state of the vertical streak without the side effects 1 and 2 described above. . Furthermore, the intensity (light quantity) of the irradiation region can be improved and the SN ratio can be reduced.

  Further, as in the fifth embodiment shown in FIG. 39B, when the irradiation region is a single vertically long light spot, the shape of the light spot may be a square shape. Here, “square” means a shape between an ellipse and a rectangle. By making the shape of the light spot close to a rectangle, it becomes possible to make the scratched part in the light spot larger than the elliptical light spot having the same width in the sub direction as the light spot, and in the sub direction of the scratched state. Since the variation can be averaged, the detection accuracy is improved. In order to make the shape of the light spot square, the shape of the light emitting portion needs to be substantially rectangular.

  Note that each of the plurality of light spots arranged in the sub-direction illustrated in FIG. The “square shape” here means a shape between a circle and a square. Also in this case, the detection accuracy can be further improved. In order to make the shape of the light spot square, it is necessary to make the shape of the light emitting portion substantially square.

  Here, as in Comparative Example 3 shown in FIG. 40A, a case where a plurality of horizontally long light spots are formed on the fixing belt 61 side by side in the main direction by a reflective optical sensor is shown in FIG. 40B. A case where a plurality of vertically long light spots are arranged in the main direction on the fixing belt 61 by a reflective optical sensor as in the modification 6 and a light spot is formed on the flaw of the fixing belt 61 (case 1). In comparison, the detection accuracy of Example 6 can be made higher than that of Comparative Example 3. That is, in case 1, when the shape of the light spot is vertically long rather than horizontally long, the ratio of the scratches in the light spot increases, and the detection accuracy increases.

  On the other hand, when Comparative Example 3 and Example 6 are compared in the case where two light spots are formed at positions where the flaw of the fixing belt 61 is sandwiched (case 2), Comparative Example 3 is detected more than Example 6. The accuracy can be increased (see FIGS. 41A and 41B). In other words, in case 2, when the shape of the light spot is horizontally long rather than vertically long, the ratio of the scratched portion in the light spot increases, and the detection accuracy increases.

  Therefore, in Example 6, in order to improve the detection accuracy in Case 2, it is conceivable to reduce the intervals in the main direction of the plurality of light spots (see FIG. 42).

  However, in this case, the total detectable range in the main direction is narrowed.

  Therefore, as in Example 7 shown in FIGS. 43A and 43B, the reflective optical sensor of Example 6 is moved in the main direction, detection is performed at a plurality of positions in the main direction, and fixing is performed. If the detection result when the light spot is formed on the scratch on the belt 61 and the detection result when the light spot is formed on a portion where the fixing belt 61 is not damaged are used to determine the state of the scratch, It is possible to accurately determine the state of the scratch without narrowing the total detectable range of directions.

  Specifically, as shown in FIG. 43A and FIG. 43B as an example, a plurality of (for example, 20) vertically elongated light spots are formed on the fixing belt 61 by the reflective optical sensor of the seventh embodiment. After S-1 to S-20 are formed at equal intervals, the reflective optical sensor is moved in the main direction by L / 2, which is half of the light spot pitch L (interval between the centers of two adjacent light spots). 20 vertical light spots S-1 to S-20 are formed at equal intervals on the fixing belt 61, and the state of the vertical streak-like scratches is detected using the detection values of the reflective optical sensor before and after the movement. If determined, the resolution in the main direction, which is the arrangement direction of the light spots, can be doubled. The reflective optical sensor of Example 7 includes 20 light emitting units or light emitting unit groups arranged at equal intervals in the Y-axis direction.

  Further, the movement distance of the reflective optical sensor in the main direction is (L / N), (L / N) × 2, (L / N) × 3,..., (L / N) × (N−1). ) (Where N is an integer equal to or greater than 3), the light spots S-1 to S-20 are formed on the fixing belt 61, respectively, and the reflective optical system is positioned at each of the N-1 positions. If the state of the wound is determined using the detection value of the sensor, detection with higher resolution can be performed.

  In addition, since the reflective optical sensor of Example 7 can be moved in the main direction, the number of light emitting portions (the number of light spots) can be reduced as shown in FIG. Can also be realized.

  As a means for moving the reflective optical sensors of Examples 3 and 7, a solenoid actuator using a magnetic field when a coil is energized and a magnetic field of a permanent magnet, a motor as a driving source, a rack and pinion mechanism, a ball Examples include an actuator that converts a rotational motion including a screw mechanism into a linear motion. Although the reflective optical sensors of Examples 3 and 4 are moved in the main direction, the point is that the reflection type optical sensors may be moved in the direction intersecting the sub direction (the moving direction of the fixing belt 61).

  Then, by providing a position sensor that measures the movement distance of the reflective optical sensor, the measurement result of the position sensor is fed back to the control unit that controls the actuator, so that the reflective optical sensor can be accurately It can be moved to a position.

  In addition, as described above, Examples 1 to 7 are also modifications of the above-described embodiment, and the reflective optical sensor, the surface information detection device, and the color printer of Examples 1 to 7 are each a reflective optical sensor according to the above-described embodiment. The sensor 200, the surface information detection device 500, and the color printer 100 have the same configuration.

  That is, in the color printers of the first to seventh embodiments, the recording sheet S (recording medium) on which the image is transferred is brought into contact with the fixing belt 61 (moving body) for fixing the image, and at least one light emitting unit. A reflection type optical sensor having at least one light source comprising at least one irradiation system for irradiating the fixing belt 61 with light, and surface information of the fixing belt 61 based on an output signal of the reflection type optical sensor. An irradiation area formed on the fixing belt 61 by the light from the light source, a direction (main direction) orthogonal to the moving direction rather than the width of the fixing belt 61 in the moving direction (sub direction). ) Is narrower.

  According to the first to seventh embodiments, the surface information of the fixing belt 61 can be obtained stably and accurately.

  In Examples 2, 3, 6, and 7, a plurality of irradiation areas are formed side by side in the main direction. However, the present invention is not limited to this, and the point is that the direction intersects the sub direction (the movement direction of the fixing belt 61). They may be formed side by side. That is, a plurality of light emitting units or a plurality of light emitting unit groups may be arranged side by side in a direction parallel to the direction intersecting the sub direction.

  Incidentally, in the above-described embodiment and each example, a surface polishing apparatus that polishes the surface of the fixing belt 61 may be provided in the image forming apparatus. In this case, the influence of scratches generated on the surface of the fixing belt can be reduced by polishing the surface of the fixing belt flat with the surface polishing apparatus. For example, the surface of the fixing belt can be polished more flatly by adjusting the polishing position, polishing time, and polishing force by the polishing device based on the detection result of the reflective optical sensor, and fixing unevenness occurs. Can be suppressed, and as a result, the image quality can be improved.

  Below, the surface polishing apparatus 1000 which is a specific example of a surface polishing apparatus is demonstrated.

  As an example, the surface polishing apparatus 1000 is disposed in a housing of the color printer 100 (see FIG. 1A), and as shown in FIGS. 45A and 45B, the surface of the fixing belt 61 is removed. A drive including a polishing roller 800 for polishing, and a motor as a drive source for moving the polishing roller 800 between a position where it abuts on the fixing belt 61 and a retracted position where it is retracted from the corresponding contact position, and rotationally driving it. Unit 900 and a control unit 950 for controlling the drive unit 900 based on the detection result of the reflective optical sensor.

  More specifically, the control unit 950 controls the polishing roller 800 via the drive unit 900 according to the determination result of the surface information from the processing apparatus 300. More specifically, the processing device 300 determines the effect of flaws on the fixing belt 61 on the image based on the output signal of the reflective optical sensor, and outputs the determination result to the control unit 950. When the control unit 950 receives the determination result that the scratch is at a level that makes the image quality NG (a level that does not satisfy the acceptance standard), the control unit 950 performs surface polishing of the fixing belt 61 using the surface polishing apparatus 1000.

  Note that the control unit 950 may receive the output signal of the reflective optical sensor and perform the above determination itself. In this case, the control unit 950 performs the polishing operation on the surface of the fixing belt 61 using the surface polishing apparatus 1000 when it is determined that the vertical streak is at a level that makes the image quality NG.

  As shown in FIGS. 45 (A) and 45 (B), the polishing roller 800 is rotatably provided around the Y axis at the other end of an arm 69 fixed at one end to a rotation shaft 68 parallel to the Y axis. It has been. The rotating shaft 68 and the shaft of the polishing roller 800 are individually driven to rotate by the drive unit 900.

  The length of the polishing roller 800 in the Y-axis direction (the width direction of the fixing belt 61) is set to be longer than the width of the fixing belt 61 so that the entire width direction of the fixing belt 61 can be polished.

  In this case, the fixing belt 61 can not only flatten the portion including the vertical streak-like scratches formed in the fixing belt 61 due to sliding with both ends in the width direction (Y-axis direction both ends) of the recording paper S. The flatness of the surface of the fixing belt 61 can be improved over substantially the entire area in the width direction of the 61 (the surface can be made uniform), and the fixing belt 61 can be effectively used against scratches caused by the separation claw and the contact temperature sensor, or offset. Can improve the surface condition.

  In addition, the numerical values of parameters such as the LED arrangement pitch, the PD arrangement pitch, and the lens curvature radius in the above embodiment and each example are not limited to the above-described numerical values.

  Moreover, in the said embodiment and each Example, although several PD was provided corresponding to several LED separately, one PD may be provided corresponding to several LED.

  Moreover, in the said embodiment and each Example, although several PD was provided corresponding to several LED separately, even if one PD containing several light-receiving area | region corresponding to several LED is provided. Good.

  In the above embodiment and each example, the light receiving lens converges the reflected light from the fixing belt 61 only in the direction orthogonal to the Y-axis direction. It is preferable to converge in an orthogonal direction.

  Moreover, in the said embodiment and each Example, although the lens for irradiation of a some irradiation system and the lens for light reception are integrated, a separate body may be sufficient.

  Moreover, in the said embodiment and each Example, although the opening body provided with the opening located between the LED group containing several LED of each of several irradiation system and the lens for irradiation is provided, it does not necessarily provide. It does not have to be done.

  If no opening is provided, steps J3 to J6 and J10 are unnecessary in FIG. 16, steps U1 to U4 and U8 are unnecessary in FIG. 17, and steps W3 to W6, W10, and FIG. W17 to W19 and W23 are unnecessary.

  In the above embodiment and each example, light is sequentially irradiated to a plurality of positions in the Y-axis direction of the fixing belt 61. However, at least two positions may be irradiated simultaneously.

  In the above embodiment and each example, the fixing belt is adopted as the detection target of the surface information detection device. However, the present invention is not limited to this. It can be set as a detection target of the detection device. For example, the transfer belt 11 may be employed as the moving body, and the surface information of the transfer belt 11 may be detected in the same manner as in the above-described embodiments and examples. In this case, based on the detected surface information of the transfer belt 11, for example, the charging condition by the charging device, the exposure condition by the optical scanning device 13, the developing condition by the developing device, the transfer condition by the transferring device, and the like are controlled. Uneven transfer of the toner image to the paper S (transfer material) can be suppressed.

  That is, the surface information detection apparatus including the reflective optical sensor and the processing apparatus performs an object processing apparatus (for example, an image forming process, a rolling process, and a transport process) on an object (for example, a recording medium, a steel material, a transported object) (for example, an object processing apparatus). An image forming apparatus, a rolling processing apparatus, a belt conveyor apparatus, and a movable body (for example, a fixing belt 61, a transfer belt 11, a rolling roller, a rolling belt, and a conveying belt) on which surface information is detected. ).

  In the above-described embodiment and each example, the fixing device 19 includes the fixing belt 61 as a moving body. However, instead of this, the fixing device 19 may include a fixing roller as a moving body. In this case, the recording paper S is conveyed to the nip formed by the fixing roller and the pressure roller. That is, the moving body may be not only an endless belt but also a roller. The moving body may be a reciprocating member as well as a rotating belt and a rotating roller.

  Further, in the above-described embodiment and each example, the optical scanning device 13 as the exposure device is controlled based on the detection result of the reflective optical sensor. For example, the developing bias by the developing device, the transfer potential by the transfer device, the charging potential by the charging device, and the like may be controlled such that the toner adhesion amount at the position becomes larger than the toner adhesion amount at a position where there is no scratch.

  In the above embodiment and each example, the case where the image forming apparatus has four photosensitive drums has been described. However, the present invention is not limited to this. Specifically, the image forming apparatus may be a color printer having, for example, five or more photosensitive drums, or may be a monochrome printer having one photosensitive drum, for example.

  Moreover, in the said embodiment and each Example, although LED is used as a light emission part of a reflection type optical sensor, it is not restricted to this, For example, an organic EL element, an end surface emitting laser, a surface emitting laser, other lasers, etc. May be used.

  In the above embodiment and each example, the optical scanning device 13 is employed as the image writing device (exposure device). However, the present invention is not limited to this, and a plurality of images arranged side by side in one axis direction (for example, the Y axis direction). An optical print head that includes a light emitting unit and irradiates the photosensitive drum with a plurality of lights modulated according to image information to form a latent image may be employed. In this case, based on the detection result of the reflective optical sensor, at least one light emitting unit emits light so that the toner adhesion force at the flawed position on the fixing belt is larger than the toner adhesion amount at the flawless position. The amount of light may be adjusted.

  In the embodiment and each example, as the “reference reflector”, a glass plate, an opening, a fixing belt 61 in an unused state, and the like are used. It is preferably a member that does not reflect information (information related to scratches), and more preferably a member that has a uniform reflectance in a region irradiated with light.

  DESCRIPTION OF SYMBOLS 61 ... Fixing belt (moving body), 100 ... Color printer (image forming apparatus), 200 ... Reflective optical sensor, 211 ... LED (light emission part, a part of irradiation system), 220 ... Irradiation lens (one of irradiation system) Part), 300 ... processing device, 650 ... light shielding member, 1000 ... surface polishing device, S ... recording paper (recording medium).

Japanese Patent No. 4632820

Claims (11)

A moving body for contacting the recording medium to which the image is transferred and fixing the image;
A reflective optical sensor having at least one light source including at least one light emitting unit, and including at least one irradiation system for irradiating the movable body with light;
A processing device for obtaining surface information of the movable body based on an output signal of the reflective optical sensor,
Irradiation region formed on the movable body by the light from the light source, more of the width in the direction perpendicular to the moving direction than the moving direction of width of the moving body is rather narrow,
The reflective optical sensor is movable in a direction intersecting the moving direction;
The processing device obtains surface information of the movable body based on an output signal of the reflective optical sensor when the reflective optical sensor is located at each of a plurality of positions related to a direction intersecting the moving direction. An image forming apparatus. The irradiation system includes a lens disposed on an optical path of light from the light source,
The light source is composed of one light emitting unit,
The image forming apparatus according to claim 1, wherein the irradiation region is a light spot emitted from the light emitting unit and formed on the moving body by light passing through the lens. The irradiation system includes a lens disposed on an optical path of light from the light source,
The light source includes a plurality of the light emitting units arranged in a direction parallel to the moving direction,
The said irradiation area | region consists of a several light spot arranged in the said moving direction formed in the said moving body by the several light inject | emitted from the said several light emission part and passing through the said lens. The image forming apparatus described.   The image forming apparatus according to claim 2, wherein the light spot is rectangular. The at least one irradiation system is a plurality of irradiation systems;
5. The image formation according to claim 1, wherein a plurality of the irradiation regions are formed on the movable body in a direction intersecting the moving direction by the plurality of irradiation systems. apparatus. The plurality of irradiation areas are formed at equal intervals on the moving body,
The spacing between two adjacent positions of the plurality of positions, the image forming apparatus according to any one of claims 1 to 5, characterized in that said at more of the following pitch L of the irradiation region. The image forming apparatus according to claim 6 , wherein the plurality of positions are N−1 positions where N is an integer, and an interval between two adjacent positions is L / N. A light shielding member capable of moving between a light shielding position on an optical path between the reflective optical sensor and the moving body and a retreat position retracted from the light shielding position;
The processing unit, according to claim 1-7, wherein the light blocking member based on an output signal of the reflective optical sensor when located at the respective blocking position and the retracted position, and obtains the surface information of the movable body The image forming apparatus according to claim 1. The recording medium is in the form of a sheet,
The surface information is any one of claims 1-8, characterized in that the end portion in the width direction of the recording medium and the moving body is information about the scratches generated on the moving body by sliding The image forming apparatus described in the item. The image forming apparatus according to claim 9 , further comprising a surface polishing apparatus that polishes the surface of the movable body based on an output signal of the reflective optical sensor. An object processing apparatus for processing an object,
A moving body against which the object abuts;
A reflective optical sensor having at least one light source including at least one light emitting unit, and including at least one irradiation system for irradiating the movable body with light;
A processing device for obtaining surface information of the movable body based on an output signal of the reflective optical sensor,
Irradiation region formed on the movable body by the light from the light source, more of the width in the direction perpendicular to the moving direction than the moving direction of width of the moving body is rather narrow,
The reflective optical sensor is movable in a direction intersecting the moving direction;
The processing device obtains surface information of the movable body based on an output signal of the reflective optical sensor when the reflective optical sensor is located at each of a plurality of positions related to a direction intersecting the moving direction. An object processing apparatus.