JP2012091875A - Detection device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detection device and an image forming apparatus which can suppress change of a transporting position of a recording medium to be transported due to influence of a reference member.SOLUTION: In the case of a failure or the like in an inline sensor 200, there is a case where an image is formed on the recording medium P in a state where the inline sensor 200 is turned off. In this case, a pin 354 is inserted into a through hole 364 while an evacuation face 230 is directed upward (directed toward a transporting path 60). Then, a holding member 350 is fixed at the side plate 302A of a lower housing 302 from outside using a bolt 348. By this means, because a reference roll 226 does not rotate, it is possible to suppress change of a transporting position of the recording medium P due to influence of the reference roll 226.

Description

  The present invention relates to a detection device and an image forming apparatus including the detection device.

  In the image forming apparatus described in Patent Document 1, an image reading unit (detection device) that is arranged on the downstream side of the image forming unit on the paper conveyance path and reads an image on a sheet on which an image is formed in the image forming unit. ) Is provided.

  The image reading unit includes a counter member that has a plurality of reference surfaces and is rotatably provided, and an image reading unit that reads the reference surfaces provided on the counter member.

JP 2010-114498 A

  An object of the present invention is to prevent the conveyance posture of a recording medium to be conveyed from being changed due to the rotation of a counter member.

  According to a first aspect of the present invention, there is provided a detection apparatus comprising: an irradiating unit that irradiates light in a direction of a conveyance path through which a medium is conveyed; and a light receiving unit that receives reflected light of light emitted from the irradiating unit. And detecting means for detecting the image on the medium or the medium transported in the transport path, and the irradiation means sandwiching the medium when the irradiation means irradiates the medium with light. The first surface facing the means and the irradiation means at a position farther from the irradiation means than the first surface with the medium sandwiched when the irradiation medium is not irradiated with light. The second surface facing the means is provided in a phase different from the surface, and a voltage is applied to the facing member that switches between the first surface and the second surface by rotating around the rotation axis. The counter member is rotated or Driving means for driving to stop, in a state where the driving means is not energized, characterized in that it comprises a holding means for holding the rotational position of said opposed member.

  According to a second aspect of the present invention, there is provided the detection device according to the first aspect, wherein the holding means is detachably fixed to the engaging portion formed on the facing member and the apparatus main body, and is attached to the engaging portion. And an engaged portion to be engaged.

  The detection device according to claim 3 of the present invention is the detection device according to claim 2, wherein the engaging portion is a recess formed in the facing member, and the engaged portion is fitted into the recess from the outside. In other words, it is a convex portion that holds the rotation of the facing member.

  A detection device according to a fourth aspect of the present invention is the detection device according to any one of the first to third aspects, wherein the center of gravity of the facing member is on the rotation axis when viewed from the rotation axis direction. The thickness of the plate member constituting the second surface is increased.

  A detection device according to a fifth aspect of the present invention is the detection device according to any one of the first to third aspects, wherein the opposing member rotates only in one direction, and the first surface faces the conveyance path side. When facing, the opposing member is loaded with a load on the one direction side by gravity.

  According to a sixth aspect of the present invention, in the detection device according to the fifth aspect, the first surface is formed with an image for detecting a detection position where the detection means detects or a depth of focus of the detection means. It is characterized by being.

  According to a seventh aspect of the present invention, in the detection device according to the first aspect, the center of gravity of the facing member holds the facing member by gravity at a position where the second surface faces the transport path side. Features.

  According to an eighth aspect of the present invention, there is provided a detection device that irradiates light in the direction of a conveyance path through which the medium is conveyed, and a light receiving unit that receives transmitted light of light emitted from the irradiation unit. And detecting means for detecting the image on the medium conveyed in the conveyance path or the medium, and the irradiation means sandwiches the medium when irradiating light to the medium conveyed A first surface opposed to the detection means, and a position at a position farther from the detection means than the first surface with the medium sandwiched when the irradiation means does not irradiate light to the medium to be conveyed. A second surface facing the detection means is provided in a phase different from the surface, and a voltage is applied to a facing member that switches between the first surface and the second surface by rotating around a rotation axis. Excited to rotate the counter member. The driving means for driving to stop, in a state where the driving means is not energized, characterized in that it comprises a holding means for holding the rotational position of said opposed member.

  An image forming apparatus according to a ninth aspect of the present invention is an image forming unit that forms an image on the medium conveyed by a conveying unit, and detects an image formed on the medium by the image forming unit or the medium. The detection apparatus of any one of claim | item 1 -8 is provided, It is characterized by the above-mentioned.

  According to the detection device of the first aspect of the present invention, the conveyance posture of the recording medium to be conveyed is opposed to that in the case where the opposed member is rotatable in a state where the drive source is not energized and excited. It can suppress changing with the influence of rotation of a member.

  According to the detection device of the second aspect of the present invention, the retracting surface is more effective than the case where the engaging member that engages with the engaged member fixed to the device main body is not provided on the opposing member. The opposing member can be held at a position facing the transport path side.

  According to the detection device of the third aspect of the present invention, the retraction surface can be moved along the transport path with an inexpensive configuration as compared with the case where the concave member that engages with the convex portion fixed to the main body of the device is not provided. The opposing member can be held at a position facing the side.

  According to the detection device of claim 4 of the present invention, the backlash can be suppressed by placing the center of gravity on the rotating shaft as compared with the case where the center of gravity of the opposing member is not disposed on the rotating shaft.

  According to the detection device of claim 5 of the present invention, when the first surface faces the conveyance path side, the opposing member is compared with a case where a load is applied to the other side opposite to the one direction side by gravity. And when the 1st surface turns to the conveyance path | route side, the backlash of an opposing member can be suppressed.

  According to the detection device of the sixth aspect of the present invention, the detection accuracy with which the detection means detects the depth of focus can be improved as compared with the case where this configuration is not provided.

  According to the detection device of claim 7 of the present invention, as compared with the case where the position of the center of gravity of the opposing member is not determined with respect to the rotation shaft so that the opposing member is held at a position where the retreat surface faces the conveyance path side. Thus, it is possible to prevent the transport posture of the transported recording medium from changing due to the influence of the opposing member.

  According to the detection device of the eighth aspect of the present invention, the conveyance posture of the recording medium to be conveyed is opposed to that in the case where the opposed member can be rotated in a state where the drive source is not energized and excited. It can suppress changing with the influence of rotation of a member.

  According to the image forming apparatus of the ninth aspect of the present invention, as compared with the case where the detecting device according to any one of the first to fourth aspects is not provided, a defect such as a paper jam of the conveyed recording medium is caused. Can be suppressed.

It is the perspective view which showed the lower housing provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is the perspective view which showed the lower housing provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is the perspective view which showed the lower housing provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is the perspective view which showed the lower housing provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is the perspective view which showed the lower housing provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is the perspective view which showed the lower housing provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is the perspective view which showed the lower housing provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is the perspective view which showed the baffle provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is sectional drawing which showed the lower unit provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is the top view which showed the composite test | inspection surface of the reference | standard roll provided in the inline sensor which concerns on 1st Embodiment of this invention. It is sectional drawing which showed the substrate chamber etc. which were provided in the in-line sensor which concerns on 1st Embodiment of this invention. It is sectional drawing which showed the in-line sensor which concerns on 1st Embodiment of this invention. 1 is a cross-sectional view illustrating an image forming unit employed in an image forming apparatus according to a first embodiment of the present invention. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention. It is sectional drawing which showed the reference | standard roll employ | adopted as the in-line sensor which concerns on 2nd Embodiment of this invention. It is sectional drawing which showed the lower unit provided in the in-line sensor which concerns on 3rd Embodiment of this invention.

  An example of the detection apparatus and the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS.

(overall structure)
The image forming apparatus 10 according to the present embodiment forms a full-color image or a black-and-white image. As shown in FIG. 14, the first processing unit that constitutes a horizontal one side (left side in FIG. 14) A first housing 10A accommodated, and a second housing 10B that is separably connected to the first housing 10A and that accommodates a second processing unit that constitutes the other side in the horizontal direction (the right side in FIG. 14). It has.

  An image signal processing unit 13 that performs image processing on image data sent from an external device such as a computer is provided on the second housing 10B.

  On the other hand, the first special color (V), second special color (W), yellow (Y), magenta (M), cyan (C), and black (K) toners are provided on the upper portion of the first housing 10A. Toner cartridges 14V, 14W, 14Y, 14M, 14C, and 14K are provided so as to be replaceable along the horizontal direction.

  The first special color and the second special color are appropriately selected from colors other than yellow, magenta, cyan, and black (including transparency). In the following description, the first special color (V), the second special color (W), yellow (Y), magenta (M), cyan (C), and black (K) are distinguished for each component. Is described with a letter followed by any letter of V, W, Y, M, C, or K. The first special color (V), the second special color (W), yellow (Y), magenta When not distinguishing (M), cyan (C), and black (K), V, W, Y, M, C, and K are omitted.

  Further, under the toner cartridge 14, image forming units 16 as an example of six image forming units corresponding to the toners of the respective colors are provided along the horizontal direction so as to correspond to the toner cartridges 14. .

  An exposure device 40 provided for each image forming unit 16 receives the image data subjected to the image processing by the image signal processing unit 13 from the image signal processing unit 13 and modulates the light beam L according to the image data. Is applied to an image holding member 18 described later (see FIG. 13).

  As shown in FIG. 13, each image forming unit 16 includes an image carrier 18 that is rotationally driven in one direction (clockwise direction in FIG. 13). By irradiating each image carrier 18 with the light beam L from each exposure device 40, an electrostatic latent image is formed on each image carrier 18. Details of the exposure apparatus 40 will be described later.

  Around each image carrier 18, an electrostatic latent image formed on the image carrier 18 by a corona discharge method (non-contact charging method) scorotron charger 20 that charges the image carrier 18 and an exposure device 40. A developing device 22 that develops with a developer, a blade 24 as a removing member that removes the developer remaining on the image carrier 18 after transfer, and a static eliminator that performs static elimination by irradiating the image carrier 18 after transfer with light. A device 26 is provided.

  The scorotron charger 20, the developing device 22, the blade 24, and the charge eliminating device 26 are arranged in this order from the upstream side to the downstream side in the rotation direction of the image carrier 18 so as to face the surface of the image carrier 18. .

  The developing device 22 includes a developer accommodating member 22A that accommodates a developer G containing toner, and a developing roll 22B that supplies the developer G accommodated in the developer accommodating member 22A to the image carrier 18. Has been. The developer accommodating member 22A is connected to the toner cartridge 14 (see FIG. 14) through a toner supply path (not shown), and the toner is supplied from the toner cartridge 14.

  As shown in FIG. 14, a transfer unit 32 is provided below each image forming unit 16. The transfer unit 32 includes an annular intermediate transfer belt 34 that is in contact with each image carrier 18, and a primary transfer roll 36 that serves as a primary transfer member that multiplex-transfers the toner image formed on each image carrier 18 onto the intermediate transfer belt 34. It is comprised including.

  The intermediate transfer belt 34 includes a drive roll 38 driven by a motor (not shown), a tension applying roll 41 that applies tension to the intermediate transfer belt 34, a counter roll 42 that faces a secondary transfer roll 62 described later, and a plurality of rolls. It is wound around the winding roll 44 and is circulated and moved in one direction (counterclockwise direction in FIG. 14) by the drive roll 38.

  Each primary transfer roll 36 is disposed opposite to the image carrier 18 of each image forming unit 16 with the intermediate transfer belt 34 interposed therebetween. The primary transfer roll 36 is applied with a transfer bias voltage having a polarity opposite to the toner polarity by a power supply unit (not shown). With this configuration, the toner image formed on the image carrier 18 is transferred to the intermediate transfer belt 34.

  On the opposite side of the drive roll 38 across the intermediate transfer belt 34, there is provided a removing device 46 that removes residual toner, paper dust and the like on the intermediate transfer belt 34 by bringing the blade into contact with the intermediate transfer belt 34. .

  Below the transfer unit 32, two recording medium storage units 48 that store a recording medium P as an example of a medium such as paper are provided along the horizontal direction.

  Each recording medium accommodating portion 48 can be pulled out from the first housing 10A. Above one end side (the right side in FIG. 14) of each recording medium accommodating portion 48, a delivery roll 52 for sending the recording medium P from each recording medium accommodating portion 48 to the transport path 60 is provided.

  In each recording medium accommodating portion 48, a bottom plate 50 on which the recording medium P is placed is provided. The bottom plate 50 is lowered by an instruction of a control unit (not shown) when the recording medium accommodating portion 48 is pulled out from the first housing 10A. When the bottom plate 50 is lowered, a space in which the user replenishes the recording medium P is formed in the recording medium accommodating portion 48.

  When the recording medium accommodating portion 48 pulled out from the first housing 10A is attached to the first housing 10A, the bottom plate 50 is raised by an instruction from the control means. As the bottom plate 50 moves up, the uppermost recording medium P placed on the bottom plate 50 and the delivery roll 52 come into contact with each other.

  On the downstream side in the recording medium conveyance direction of the delivery roll 52 (hereinafter sometimes simply referred to as “downstream side”), a separation roll 56 that separates the recording media P delivered from the recording medium accommodating portion 48 one by one. Is provided. A plurality of transport rolls 54 that transport the recording medium P downstream in the transport direction are provided on the downstream side of the separation roll 56.

  The conveyance path 60 provided between the recording medium container 48 and the transfer unit 32 is configured to fold the recording medium P sent out from the recording medium container 48 to the left side in FIG. It extends to the transfer position T between the secondary transfer roll 62 and the opposing roll 42 so as to be folded back to the right side in FIG.

  The secondary transfer roll 62 is applied with a transfer bias voltage having a polarity opposite to the toner polarity by a power feeding unit (not shown). With this configuration, the toner images of each color that have been multiplex-transferred onto the intermediate transfer belt 34 are secondarily transferred onto the recording medium P that has been transported along the transport path 60 by the secondary transfer roll 62.

  A preliminary path 66 extending from the side surface of the first housing 10 </ b> A is provided so as to join the second folding portion 60 </ b> B of the transport path 60. The recording medium P sent out from another recording medium accommodation unit (not shown) arranged adjacent to the first housing 10 </ b> A can enter the conveyance path 60 through the spare path 66.

  On the downstream side of the transfer position T, a plurality of conveying belts 70 that convey the recording medium P on which the toner image has been transferred toward the second casing 10B are provided in the first casing 10A, and are conveyed to the conveying belt 70. A transport belt 80 that transports the recording medium P to the downstream side is provided in the second housing 10B.

  Each of the plurality of conveyance belts 70 and the conveyance belt 80 is formed in an annular shape and is wound around a pair of winding rolls 72. The pair of winding rolls 72 are respectively arranged on the upstream side and the downstream side in the conveyance direction of the recording medium P, and when one of them is driven to rotate, the conveyance belt 70 (conveyance belt 80) moves in one direction (in FIG. 14). Cycle in the clockwise direction.

  A fixing unit 82 for fixing the toner image transferred onto the surface of the recording medium P to the recording medium P with heat and pressure is provided on the downstream side of the conveyance belt 80.

  The fixing unit 82 includes a fixing belt 84 and a pressure roll 88 disposed so as to contact the fixing belt 84 from below. A fixing unit N is formed between the fixing belt 84 and the pressure roll 88 to fix the toner image by pressurizing and heating the recording medium P.

  The fixing belt 84 is formed in an annular shape and is wound around the drive roll 89 and the driven roll 90. The drive roll 89 faces the pressure roll 88 from above, and the driven roll 90 is disposed above the drive roll 89.

  Each of the driving roll 89 and the driven roll 90 includes a heating unit such as a halogen heater. As a result, the fixing belt 84 is heated.

  As shown in FIG. 14, on the downstream side of the fixing unit 82, a conveyance belt 108 that conveys the recording medium P sent out from the fixing unit 82 to the downstream side is provided. The conveyor belt 108 is formed in the same manner as the conveyor belt 70.

  A cooling unit 110 that cools the recording medium P heated by the fixing unit 82 is provided on the downstream side of the conveyance belt 108.

  The cooling unit 110 includes an absorption device 112 that absorbs the heat of the recording medium P, and a pressing device 114 that presses the recording medium P against the absorption device 112. The absorbing device 112 is disposed on one side (upper side in FIG. 14) with respect to the conveyance path 60, and the pressing device 114 is disposed on the other side (lower side in FIG. 14).

  The absorption device 112 includes an annular absorption belt 116 that contacts the recording medium P and absorbs the heat of the recording medium P. The absorption belt 116 is wound around a driving roll 120 that transmits a driving force to the absorption belt 116 and a plurality of winding rolls 118.

  A heat sink 122 made of an aluminum material that dissipates heat absorbed by the absorption belt 116 by contacting the absorption belt 116 in a planar shape is provided on the inner peripheral side of the absorption belt 116.

  Furthermore, a fan 128 for removing heat from the heat sink 122 and discharging the hot air to the outside is disposed on the back side of the second housing 10B (the back side of the paper surface shown in FIG. 14).

  The pressing device 114 that presses the recording medium P against the absorbing device 112 includes an annular pressing belt 130 that conveys the recording medium P while pressing the recording medium P against the absorbing belt 116. The pressing belt 130 is wound around a plurality of winding rolls 132.

  On the downstream side of the cooling unit 110, there is provided a correction device 140 that conveys the recording medium P and corrects the curl of the recording medium P.

  On the downstream side of the correction device 140, an in-line sensor 200 is provided as an example of a detection device that detects a toner density defect, an image defect, an image position defect, and the like of the toner image fixed on the recording medium P. Details of the inline sensor 200 will be described later.

  On the downstream side of the inline sensor 200, a discharge roll 198 is provided for discharging the recording medium P having an image formed on one side thereof to a discharge unit 196 attached to the side surface of the second housing 10B.

  On the other hand, when images are formed on both sides, the recording medium P sent from the inline sensor 200 is conveyed to a reversing path 194 provided on the downstream side of the inline sensor 200.

  The reversing path 194 includes a branch path 194A that branches from the transport path 60, a paper transport path 194B that transports the recording medium P transported along the branch path 194A toward the first housing 10A, and a paper transport path. A reversing path 194C is provided for turning the recording medium P conveyed along 194B in the reverse direction to switch back and reversing it.

  With this configuration, the recording medium P that is switched back and conveyed by the reverse path 194C is conveyed toward the first housing 10A, and further enters the conveyance path 60 provided above the recording medium container 48, and is transferred to the transfer position. It is sent to T again.

  Next, an image forming process of the image forming apparatus 10 will be described.

  The image data that has been subjected to image processing by the image signal processing unit 13 is sent to each exposure device 40. In each exposure device 40, each light beam L is emitted according to the image data and exposed to each image carrier 18 charged by the scorotron charger 20, and an electrostatic latent image is formed.

  As shown in FIG. 13, the electrostatic latent image formed on the image carrier 18 is developed by the developing device 22, and the first special color (V), the second special color (W), yellow (Y), Magenta (M), cyan (C), and black (K) toner images are formed.

  As shown in FIG. 14, the toner images of the respective colors formed on the photoreceptors 18 of the image forming units 16V, 16W, 16Y, 16M, 16C, and 16K have six primary transfer rolls 36V, 36W, 36Y, 36M, Multiple transfer is sequentially performed on the intermediate transfer belt 34 by 36C and 36K.

  The toner images of the respective colors that have been multiplex-transferred onto the intermediate transfer belt 34 are secondarily transferred onto the recording medium P conveyed from the recording medium accommodating portion 48 by the secondary transfer roll 62. The recording medium P onto which the toner image has been transferred is transported toward the fixing unit 82 provided inside the second housing 10B by the transport belt 70.

  The toner images of the respective colors on the recording medium P are fixed on the recording medium P by being heated and pressurized by the fixing unit 82. Further, the recording medium P on which the toner image is fixed is cooled by passing through the cooling unit 110 and then sent to the correction device 140 to correct the curvature generated in the recording medium P.

  The recording medium P whose curvature is corrected is discharged to the discharge unit 196 by the discharge roll 198 after an image defect or the like is detected by the in-line sensor 200.

  On the other hand, when an image is formed on a non-image surface where no image is formed (in the case of double-sided printing), after passing through the inline sensor 200, the recording medium P is reversed by the reversing path 194 and above the recording medium container 48. And a toner image is formed on the back surface according to the above-described procedure.

  In the image forming apparatus 10 according to the present embodiment, components for forming images of the first special color and the second special color (image forming units 16V and 16W, exposure devices 40V and 40W, toner cartridges 14V and 14W, The primary transfer rolls 36V and 36W) are configured to be attachable to the first housing 10A as additional parts according to the user's selection. Accordingly, the image forming apparatus 10 does not include a part for forming the first special color and second special color images, and the image of any one of the first special color and the second special color. It is good also as a structure which has only the components for forming.

  Next, the inline sensor 200 will be described.

In the following description, the length direction of the image forming apparatus 10 (sub-scanning direction that is the conveyance direction of the recording medium P) is the X direction, the height direction of the apparatus is the Y direction, and the depth direction of the apparatus (main scanning direction) is Z. The direction.
(Basic configuration and function of inline sensor)
As shown in FIG. 12, the inline sensor 200 receives an irradiation unit 202 that irradiates light toward a recording medium P on which an image is recorded, and light that is irradiated from the irradiation unit 202 and reflected by the recording medium P. An image forming unit 208 including an image forming optical system 206 that forms an image on a CCD sensor 204 as an example of a means, and a setting unit 210 in which various standards are set when the inline sensor 200 is used or calibrated. ing. Note that the detection unit 201 that detects an image on the recording medium P conveyed along the conveyance path 60 includes an irradiation unit 202 and an imaging unit 208.

  The irradiation unit 202 is disposed on the upper side of the conveyance path 60 of the recording medium P, and has a pair of lamps 212 as an example of irradiation means. Each of the lamps 212 is a xenon lamp that is elongated in the Z direction, and the length of the irradiation range is larger than the width of the maximum recording medium P to be conveyed. The pair of lamps 212 are arranged symmetrically with respect to the optical axis OA (designed optical axis) that is reflected by the recording medium P and travels toward the image forming unit 208. More specifically, the lamps 212 are arranged symmetrically with respect to the optical axis OA so that the irradiation angles to the recording medium P are 45 ° to 50 °, respectively.

  Specifically, the pair of lamps 212 is opposite to the first lamp 212A as an example of a first light source provided on the upstream side in the conveyance direction of the recording medium P, with the optical axis OA interposed therebetween. And a second lamp 212B as an example of a second light source provided on the side.

  The imaging optical system 206 reflects the light guided along the optical axis OA in the X direction (in this embodiment, on the downstream side in the conveyance direction of the recording medium P), and the first mirror 214 reflects the light. The second mirror 216 that reflects light upward, the third mirror 218 that reflects the light reflected by the second mirror 216 to the upstream side in the transport direction of the recording medium P, and the light reflected by the third mirror 218 are the CCD sensor 204. The main part is a lens 220 that focuses (images) the light. The CCD sensor 204 is arranged on the upstream side in the transport direction of the recording medium P with respect to the optical axis OA.

  The length of the first mirror 214 in the Z direction is larger than the width of the maximum recording medium P. The first mirror 214 to the third mirror 218 reflect the reflected light of the recording medium P incident on the image forming optical system 206 while reducing the reflected light in the Z direction (main scanning direction). Thus, the reflected light from each part in the width direction of the recording medium P is incident on the substantially cylindrical lens 220.

  With the above configuration, in the in-line sensor 200, the CCD sensor 204 outputs (feeds back) the imaged light, that is, a signal corresponding to the image density, to the control device 192 (see FIG. 14) of the image forming apparatus 10. ing. The control device 192 corrects an image formed in the image forming unit 16 based on a signal from the inline sensor 200. In the image forming apparatus 10, as an example, the intensity of irradiation light by the exposure apparatus 40, the image formation position, and the like are corrected based on a signal from the inline sensor 200.

  Further, a light amount diaphragm unit 224 is provided between the third mirror 218 and the lens 220 in the imaging optical system 206. The light amount diaphragm unit 224 narrows the light amount of light that forms an image on the CCD sensor 204 across the optical path in the Z direction in the Y direction (direction intersecting with the main scanning direction), and adjusts the amount of light diaphragm by operating from the outside. It is configured to be possible. The light amount stop amount by the light amount stop unit 224 is adjusted so that the light amount imaged on the CCD sensor 204 becomes a predetermined amount even if the light emission amount of each lamp 212 changes with time.

  On the other hand, the setting unit 210 includes a reference roll 226 as an example of a counter member that is long in the Z direction. The reference roll 226 is used when the image detection of the recording medium P is not performed by the detection reference surface 228 as an example of the first surface facing the conveyance path 60 when the image detection of the recording medium P is performed, and the inline sensor 200. A retraction surface 230 as an example of a second surface facing the conveyance path side, a white reference surface 232, a color reference surface 234 on which a multicolor pattern is formed along the longitudinal direction, and a plurality of inspection patterns are formed. And a combined inspection surface 236. In this embodiment, the reference roll 226 is formed in a polygonal cylindrical shape having eight or more surfaces formed in the circumferential direction. Only one detection reference surface 228, retraction surface 230, color reference surface 234, and composite inspection surface 236 are provided, and two white reference surfaces 232 are provided.

  The reference roll 226 is configured to switch the surface facing the conveyance path 60 side by rotating around the rotation shaft 226A. Switching of the surface of the reference roll 226 is performed by a control circuit provided on a circuit board 262 described later. Moreover, the reference | standard roll 226 is formed in the polygonal cylinder shape more than an octagon, The distance difference with respect to the rotation center of the circumferential direction center of each surface and the corner | angular part between surfaces is suppressed small. Thus, the corner between the surfaces of the reference roll 226 does not interfere with the irradiation unit 202 while keeping the distance between each surface of the reference roll 226 and the irradiation position (window glass 286 described later) of each lamp 212 small. ing.

  The detection reference surface 228 has a circumferential width smaller than the other surfaces, and the surfaces on both sides in the circumferential direction are guide surfaces 238 that do not have the above-described functions as the respective references. The detection reference surface 228 is a position reference surface for positioning the detected (read) surface of the conveyed recording medium P at the irradiation position by each lamp 212.

  The retracting surface 230 has a circumferential width larger than that of other surfaces. The retracting surface 230 is a guide surface that guides the recording medium P when the image detection of the recording medium P by the inline sensor 200 is not performed, and the distance from the axis of the rotating shaft 226A is smaller than the detection reference surface 228. It is said that. Accordingly, when the image detection of the recording medium P by the inline sensor 200 is not performed, the conveyance with the irradiation unit 202 (window glass 286) is wider than when the image detection of the recording medium P by the inline sensor 200 is performed. A path is formed.

  The white reference surface 232 is used for calibration of the illumination unit 202 and the imaging optical system 206, and is configured by adhering a reference white film from which a predetermined signal is output from the imaging optical system 206. . The color reference plane 234 is used for calibration of the illumination unit 202 and the imaging optical system 206, and is a film on which a reference color pattern is output in which a predetermined signal corresponding to each color is output from the imaging optical system 206. Is affixed.

  As shown in FIG. 10, the composite inspection surface 236 includes a position adjustment pattern 240 for calibrating the position of the reference roll 226 in the rotation direction (conveyance direction of the recording medium P), a focus detection pattern 242, and depth detection. The pattern 244 is formed on the same surface.

  The position adjustment pattern 240 is configured such that a black “N” pattern is pasted on a white film formed such that the vertical line of the “N” is along the conveyance direction of the recording medium P. ing. The focus detection pattern 242 is configured by adhering a white film on which a ladder pattern such as a large number of black straight lines along the conveyance direction of the recording medium P is arranged.

  The depth detection pattern 244 is a sheet material on which a pattern in which three white surfaces 244A, 244B, and 244C having different distances from the rotation axis 226A of the reference roll 226 are arranged stepwise in the longitudinal direction of the composite inspection surface 236 is formed. It is formed by sticking.

  At least one position adjustment pattern 240 is provided at both ends in the longitudinal direction of the composite inspection surface 236. The focus detection pattern 242 is disposed adjacent to the center side in the longitudinal direction of the composite inspection surface 236 with respect to the position adjustment patterns 240 disposed at both ends. A total of three depth detection patterns 244 are provided at both ends in the longitudinal direction of the composite inspection surface 236 and at the center. In this embodiment, one position adjustment pattern 240 and one focus detection pattern 242 are further arranged between the depth detection pattern 244 arranged at the center and the depth detection pattern 244 arranged at one end in the longitudinal direction.

  Next, a calibration procedure for the CCD sensor 204 will be described.

  As shown in FIG. 12, first, the white reference surface 232 is directed toward the conveyance path 60 of the recording medium P. The CCD sensor 204 outputs a shading correction signal for correcting the light amount distribution in the Z direction (main scanning direction).

  Subsequently, the composite inspection surface 236 is directed to the conveyance path 60 of the recording medium P, and the position detected by the CCD sensor 204 in the conveyance direction of the recording medium P is automatically adjusted by the position adjustment pattern 240 (see FIG. 6). . That is, by detecting the “N” -shaped pattern across the Z direction (main scanning direction), a hatched portion 240B is detected between the two straight portions 240A and 240C as shown in FIG. Then, the reference roll 226 is rotated so that the interval between the straight portion 240A and the shaded portion 240B is equal to the interval between the straight portion 240C and the shaded portion 240B, and the detection position is adjusted.

  As shown in FIG. 12, after the detection position in the conveyance direction of the recording medium P is adjusted, the focus of the CCD sensor 204 is confirmed by the focus detection pattern 242 and the illumination depth is confirmed by the depth detection pattern 244. .

  Further, the color reference surface 234 is directed to the conveyance path 60 of the recording medium P. The CCD sensor 204 is automatically adjusted so that a signal having a predetermined intensity is output for each color.

  As described above, the calibration of the CCD sensor 204 is performed, for example, when the image forming apparatus 10 is turned on (once / day). On the other hand, the calibration of the image forming apparatus 10 based on the signal from the CCD sensor 204 (adjustment of the exposure apparatus 40 described above) is performed as an example every time when a job that forms an image on a recording medium P of a predetermined amount or more ( 10 times / day).

(Division structure of inline sensor)
The above-described inline sensor 200 can be divided into a center unit 246 whose main part is the irradiation part 202, an upper unit 248 whose main part is the imaging part 208, and a lower unit 250 whose main part is the setting part 210. It is said that.

  The upper unit 248 can be attached to and detached from the second casing 10B (see FIG. 14) of the image forming apparatus 10 by sliding in the Z direction. The center unit 246 is detachable from the upper unit 248 by sliding in the Z direction. The lower unit 250 can be attached to and detached from the center unit 246 and the upper unit 248 by sliding in the Z direction. Note that the lower unit 250 arranged below the conveyance path 60 of the recording medium P is arranged only in the Z direction on a lower drawer (not shown) pulled out from the second housing 10B in order to eliminate clogging of the recording medium P. The center unit 246 and the upper unit 248 are attached to and detached from the lower drawer. This will be specifically described below.

(Configuration of upper unit)
The upper unit 248 includes an upper housing 254. The upper housing 254 accommodates the imaging unit 208 and a circuit board 262 to be described later, and configures a duct 265 as an example of a cooling main air flow path. The upper housing 254 includes an imaging system housing 256 as an example of a first aperture member that houses the CCD sensor 204 and the imaging optical system 206.

  The imaging system housing 256 is formed in a substantially rectangular box shape that is long in the X direction when viewed from the Z direction, and has one end in the X direction (in this embodiment, the end on the upstream side in the transport direction of the recording medium P). ) Houses the CCD sensor 204. A second mirror 216 and a third mirror 218 are disposed at the other end portion in the X direction of the imaging system housing 256. A window portion 256A as an example of a first passage hole through which light enters along the optical axis OA is formed at a substantially central portion in the X direction of the imaging system housing 256. In the imaging system housing 256, the window portion 256A is closed by a light-transmissive window glass 258 so that the inside is hermetically sealed (airtight) and the optical chamber 205 in which the CCD sensor 204 and the like are accommodated. Is provided.

  The upper housing 254 includes an upper cover 260 that covers the imaging system housing 256 from above. Thus, a substrate chamber 264 in which the circuit substrate 262 is accommodated is formed between the upper wall 256U of the imaging system housing 256 and the upper cover 260. In addition, the upper housing 254 includes a duct cover 268 that forms a duct 265 outside the one end in the X direction, which is the side where the CCD sensor 204 is disposed in the imaging system housing 256. The duct cover 268 covers the end of the imaging system housing 256 from the upstream side in the conveyance direction of the recording medium P and the sheet conveyance path side, and forms a duct 265 having an “L” shape in the XY cross section. Yes.

  The upper end of the duct 265 is an air intake 266A, and the end of the duct 265 opposite to the air intake 266A is a connection port 266B connected to a duct 308 as an example of a first air flow path of a lamp housing 284 described later. It is said that. The duct 265 is provided with a fan 270 as an example of an air flow generating means for generating an air flow from the upper side to the lower side in the duct 265. In addition, a fan 272 for sending air into the optical chamber 205 provided in the imaging system housing 256 (for making the inside of the optical chamber 205 positive pressure) is disposed in the duct 265. Further, the duct 265 is provided with a fan 274 (see FIG. 11) that sends air into the substrate chamber 264.

  Further, the upper housing 254 includes a cover 275 that covers the imaging system housing 256 from the second mirror 216 and the third mirror 218 side. The cover 275 forms a heat insulating space 276 between the imaging system housing 256 and the cover 275.

  The upper housing 254 is provided with a slider 278 that is elongated in the Z direction. In this embodiment, a pair of sliders 278 are provided on the upper cover 260 in parallel with the arrow X direction. Each slider 278 is fitted to a rail provided on a frame (not shown) of the second housing 10B. Accordingly, each slider 278 moves while being guided by the rail, and the upper unit 248 is moved in the Z direction with respect to the second housing 10B.

(Configuration of center unit)
The center unit 246 includes a lamp housing 284 that houses a pair of lamps 212 and a window cover 288 that holds a window glass 286 that emits light from the lamps 212 toward the recording medium P. The lamp housing 284 has a box shape that opens up and down. The upper opening end is closed by the upper housing 254 and the lower opening end is closed by the window cover 288.

  In the irradiation unit 202, the light emitted from each lamp 212 is applied to the recording medium P through the window glass 286, and the light reflected by the recording medium P passes through the window glass 286 along the optical axis OA in the lamp housing 284. It is made to enter. The reflected light from the recording medium P incident on the lamp housing 284 is configured to be guided into the image forming unit 208 through the window glass 258 of the image forming system housing 256 constituting the image forming unit 208.

  The lamp housing 284 includes a pair of sliders 290 extending in the Z direction and projecting in a flange shape from the upper opening edge in the arrow X direction. The slider 290 is fitted to a rail 292 formed on the upper housing 254. Accordingly, each slider 290 moves while being guided by the rail 292, and the lamp housing 284 is attached to and detached from the upper housing 254 (upper unit 248) in the Z direction.

  The window cover 288 is configured such that its own edge and the edge of the window glass 286 do not face the upstream side in the conveyance direction of the recording medium P. The window glass 286 closes the window 288A formed on the window cover 288, and both ends in the longitudinal direction are pressed against the window cover 288 by attachment springs (not shown). That is, the window glass 286 is configured to be detachable from the window cover 288.

  Further, the window cover 288 is detachable from the lamp housing 284. Specifically, the window cover 288 is formed in a “U” shape whose XY cross-sectional shape opens upward, and a pair of sliders 298 is provided at the opening edge. The slider 298 is fitted to a rail 300 formed on the lamp housing 284. Accordingly, each slider 298 moves while being guided by the rail 300, and the window cover 288 is attached to and detached from the window glass 286 in the Z direction. As described above, in the inline sensor 200, the window cover 288 can be replaced or cleaned as a single item.

  Although not shown, the center unit 246 and the upper unit 248 are positioned with high accuracy in the X, Y, and Z directions by pins and holes that are inserted and removed with relative movement in the Z direction. ing. The upper unit 248 and the housing are positioned in the X, Y, and Z directions with high accuracy by pins and holes that are inserted and removed with relative movement in the Z direction.

(Lower unit configuration)
The lower unit 250 includes a lower housing 302 that houses a reference roll 226 and a motor 251 (see FIG. 9) as an example of a drive unit that drives the reference roll 226. The lower housing 302 is supported by the lower drawer as described above, and the position in the Z direction is determined by the lower drawer. Further, the lower unit 250, the center unit 246, and the upper unit 248 are positioned with high accuracy in the X and Y directions by pins and holes that are inserted and removed with relative movement in the Z direction. . Accordingly, the position of the lower unit 250 in which the conveyance path 60 of the recording medium P is located between the center unit 246 and the X, Y, and Z directions with respect to the center unit 246 and the upper unit 248 is determined.

(Measures against stray light)
A baffle 304 as an example of a second aperture member is provided in the lamp housing 284 so as to surround the optical axis OA above the pair of lamps 212. As shown in FIG. 8, the baffle 304 includes at least a pair of side walls 304 </ b> S as an example of a side portion and a bottom wall 304 </ b> B as an example of a bottom portion. In this embodiment, the pair of side walls 304S are connected by a pair of front and rear walls 304F and 304R facing in the Z direction. On the bottom wall 304B, a lower window 304W is formed as an example of a second passage hole into which the optical axis OA is incident. The upper opening end of the baffle 304 surrounds the window portion 256 </ b> A of the imaging system housing 256. Therefore, the light traveling along the optical axis OA is incident on the imaging unit 208 via the baffle 304.

  The size of the baffle 304 is set so that light irradiated from the back side of each lamp 212 does not reach the window portion 256A. That is, the position of the opening edge of the lower window 304W is set so that the light emitted from the back side of each lamp 212 does not directly reach the window portion 256A. Further, the side wall 304S has an inclination angle with respect to OA so that the light irradiated from the back side of each lamp 212 does not reach the window portion 256A even if it is reflected once.

As shown in FIG. 12, in the imaging system housing 256, a plurality of partition walls 306 that partition parts other than the light guide path by the imaging optical system 206 are arranged. Each partition wall 306 has a size (upper limit) of the light passage portion in accordance with the diffusion angle of the light reflected by the recording medium P as long as the diffused light reflected by the recording medium P is not narrowed in the Y direction and the Z direction. Has a predetermined opening 306A.
(Air flow)
In the lamp housing 284, a duct 308 is formed by one side wall 304S (in this embodiment, the upstream side in the conveyance direction of the recording medium P) and the peripheral wall of the lamp housing 284. The upper open end of the duct 308 is connected to the duct 265 through the connection port 266B in a state where the lamp housing 284 is mounted on the upper housing 254. Thus, the air flow generated by the operation of the fan 270 is also generated in the lamp housing 284.

  An air discharge port 310 is formed in a portion of the peripheral wall of the lamp housing 284 located on the opposite side of the duct 308 in the X direction. Therefore, the air flow from the duct 265 is guided by the peripheral wall of the lamp housing 284 and the window cover 288 in the lamp housing 284, while the first lamp 212A on the upstream side in the conveyance direction of the recording medium P and the downstream side thereof. The air flows through the second lamp 212B and is discharged to the outside of the lamp housing 284 through the air discharge port 310.

  Further, from the lower end of the side wall 304S constituting the duct 308, an overhanging portion 312 as an example of a light shielding portion for suppressing light irradiated from the back side of the first lamp 212A from reaching the lower window 304W is provided. It is overhanging. The amount of overhang of the overhang portion 312 is set so that the cooling effect of the pair of lamps 212 by the air flow to the pair of lamps 212 is equal.

(Light stop)
The light quantity diaphragm unit 224 has a side wall 224S, an upper wall 224U, and a lower wall 224L, and has an X-Y cross-sectional shape that is open to the third mirror 218 side. A substantially rectangular opening 314 is formed in the side wall 224 </ b> S of the light quantity diaphragm 224. A rib 316 is suspended from the free end of the upper wall 224U. The light amount restrictor 224 is configured to cut light from the recording medium P and reduce the amount of light in the Y direction at the lower edge 314L of the opening 314 and the lower end 316L of the rib 316.

  One end in the longitudinal direction of the light quantity diaphragm unit 224 reaches the wall on the near side of the imaging system housing 256, and an adjustment lever (not shown) is provided at one end in the longitudinal direction of the light quantity diaphragm unit 224 through an operation hole formed in the wall. Is attached.

  The light quantity diaphragm unit 224 is rotated in accordance with the operation of the adjustment lever, and is moved to a posture in which the diaphragm quantity is gradually reduced from the initial position where the light quantity is most reduced.

(Clogging suppression structure)
As shown in FIG. 9, the conveyance path 60 between the center unit 246 (irradiation unit 202) and the lower unit 250 (setting unit 210) is configured to be higher toward the downstream side in the conveyance direction of the recording medium P. Has been. The window cover 288 and the lower housing 302 are chamfered or rounded at their respective corners, whereby the inline sensor 200 has an entrance that is a lead-in portion that faces the upstream side in the conveyance direction of the recording medium P. A chute 320 is formed.

  The upper chute 320U that forms the upper portion of the inlet chute 320 is formed of a smooth curved surface that protrudes downward. When the extension line of the detection reference surface 228 is IL when viewed from the Z direction when the detection reference surface 228 of the reference roll 226 faces the conveyance path 60 side of the recording medium P, the upper chute 320U interferes with the extension line IL. The dimension shape is set so as to be located below the upper chute 320U protruding end extension line IL.

  Further, a convex portion 322 formed of a smooth curved surface that protrudes downward is formed on the downstream side of the window cover 288 in the transport direction of the recording medium P from the window glass 286. The convex portion 322 is located above the extension line IL.

  The lower chute 320L that forms the lower part of the inlet chute 320 is brought closer to the reference roll 226 by a lower chute member 324 fixed to a flange 302F that extends inward from the opening end of the lower housing 302. A downstream end of the lower chute member 324 in the conveyance direction of the recording medium P is a rounded portion 324A that is rounded to have an upward convexity.

  On the other hand, an exit chute 326 is formed between the downstream portion of the convex portion 322 in the conveyance direction of the recording medium P and the lower housing 302. The lower chute 326L that forms the lower part of the outlet chute 326 is configured by fixing a lower chute member 328 to a flange 302F that extends outward from the opening end of the lower housing 302. A downstream end of the lower chute member 328 in the conveyance direction of the recording medium P is a rounded portion 328A that is rounded to have an upward convexity.

  Further, the detection reference surface 228 of the reference roll 226 is directed toward the recording medium P in a posture that is substantially parallel to the window glass 286 when an image is detected by the CCD sensor 204. The guide surfaces 238 provided on both sides of the detection reference surface 228 receive the recording medium P from the inlet chute 320 and guide the recording medium P toward the outlet chute 326.

  On the other hand, when the CCD sensor 204 does not detect an image, the retracting surface 230 of the reference roll 226 is closer to the window glass 286 toward the downstream side in the conveyance direction of the recording medium P (non-parallel attitude). To be directed to. The retracting surface 230 is a wide surface extending from the rounded portion 324A of the lower chute member 324 to the vicinity of the outlet chute 326, receives the recording medium P from the inlet chute 320 in the above-described posture, and toward the outlet chute 326. Guide P.

(Inline sensor action)
As shown in FIG. 12, the inline sensor 200 irradiates the recording medium P passing between the irradiation unit 202 and the setting unit 210 with a pair of lamps 212. The light reflected by the recording medium P is guided to the imaging unit 208 along the optical axis OA, and is imaged on the CCD sensor 204 by the imaging optical system 206 of the imaging unit 208. The CCD sensor 204 outputs a signal corresponding to the image density for each image position to the control device 192 of the image forming apparatus 10. The control device 192 corrects the image density, the image forming position, and the like based on the signal from the CCD sensor 204.

  On the other hand, when the CCD sensor 204 constituting the inline sensor 200 is calibrated, first, the motor of the lower unit 250 is operated so that the white reference surface 232 is directed to the conveyance path 60 of the recording medium P. The CCD sensor 204 is adjusted so that a predetermined signal is output.

  Next, as shown in FIG. 10, the composite inspection surface 236 is directed toward the conveyance path 60 of the recording medium P, and the interval between the straight line portion 240A and the shaded portion 240B of the position adjustment pattern 240, and between the 240C and the shaded portion 240B. The detection position of the CCD sensor 204 is adjusted so that the intervals are equal. Thereafter, the CCD sensor 204 is adjusted to a focus capable of reading the ladder pattern 242. Further, the output characteristics are adjusted by the depth detection pattern 244 so that the output is constant regardless of the illumination depth.

  Further, the color reference surface 234 is directed to the conveyance path 60 of the recording medium P. The CCD sensor 204 is adjusted so that a predetermined signal is output for each color.

(Main part configuration)
Next, a method for holding the rotational position of the reference roll 226 will be described.

  As shown in FIG. 7, when the in-line sensor 200 is operated, a current is supplied to a motor that drives the reference roll 226, and a coil provided in the motor (not shown) is excited, so that the reference roll 226 is It is held at a predetermined rotational position.

  However, when the power is turned off due to a failure of the inline sensor 200 or the like, current does not flow to the motor that drives the reference roll 226, so the reference roll 226 can rotate.

  As shown in FIGS. 4, 5, and 7, one side of the lower housing 302 in the Z direction (the above-described lower drawer is pulled out from the second housing 10 </ b> B: the side of arrow D shown in FIG. 4). A holding member 350 as an example of a convex portion that holds the rotational position of the reference roll 226 is provided so as to be detachable from the outside with respect to the side plate 302A of the lower housing 302.

  Specifically, as shown in FIG. 6, the holding member 350 includes a plate-like plate portion 352 and a columnar pin 354 whose base end portion is fixed to the plate portion 352. The plate portion 352 is formed with a circular through hole 352A and a positioning long hole 352B extending in the Z direction. Then, the long hole 352B is fitted into the first convex portion 356A formed on the side plate 302A of the lower housing 302, and further, the bolt 348 is inserted into the through hole 352A, and the screw hole 358 formed in the side plate 302A of the lower housing 302 is inserted. It is configured to be screwed. Accordingly, as shown in FIG. 5, the tip end side of the pin 354 protrudes toward the reference roll 226 side through the through hole 360 formed in the side plate 302A.

  Here, when the pin 354 is inserted through the through-hole 360, the pin 354 and the reference roll 226 are separated in the Z direction, and the reference roll 226 is rotatable. That is, when the in-line sensor 200 is operated, the holding member 350 is fixed at this position, so that the reference roll 226 is rotated by receiving the driving force of the motor and is held at the determined rotation position.

  On the other hand, as shown in FIGS. 1 and 3, when the retracting surface 230 is directed upward, one end of the composite inspection surface 236 of the reference roll 226 directed to the side plate 302 </ b> A is an example of a recess. A through hole 364 is provided.

  Then, with the retracting surface 230 facing upward (the state facing the transport path 60), as shown in FIGS. 1 and 2, the holding member 350 removed from the lower housing 302 is centered on the through hole 352A. The long hole 352B is fitted into the second convex portion 356B formed on the side plate 302A of the lower housing 302 by rotating 180 degrees. Further, the bolt 348 is inserted into the through hole 352A and screwed into the screw hole 358 formed in the side plate 302A of the lower housing 302. Thus, as shown in FIG. 1, the tip side of the pin 354 protrudes toward the reference roll 226 through the through hole 362 provided on the opposite side of the through hole 360 with the screw hole 358 interposed therebetween. It has become.

  When the pin 354 is inserted through the through hole 362, the pin 354 is fitted into the through hole 364 formed in the composite inspection surface 236 of the reference roll 226. As a result, even when the motor is not excited, the rotational position of the reference roll 226 is held with the retracting surface 230 facing upward (the state facing the transport path 60).

  Further, the plate member constituting the retracting surface 230 is thickened so that the center of gravity of the reference roll 226 is located on the rotating shaft 226A when viewed from the rotational axis direction (the plate member constituting the retracting surface 230). If the plate thickness is the same as the plate thickness of the other surface, the retraction surface 230 is closer to the rotation shaft 226A than the other surface, so that the position of the center of gravity is shifted).

(Function)
Next, the effect | action in the rotation operation of the reference | standard roll 266 is demonstrated.

  As shown in FIGS. 5 and 6, when the in-line sensor 200 (see FIG. 12) is operated, the holding member 350 is externally connected to the lower housing 302 with the pin 354 of the holding member 350 inserted into the through hole 360 ( It is fixed by bolts 348 from the outside. Thereby, since the pin 354 and the reference roll 226 are separated in the Z direction, the reference roll 226 is rotated by the driving force of the motor. Further, when the rotational force is not transmitted from the motor, the state in which a current is passed through the motor is maintained, and the reference roll 226 is held at a predetermined rotational position by exciting a coil provided in the motor. Is done.

  On the other hand, in the case of a failure of the inline sensor 200, an image may be formed on the recording medium P with the power of the inline sensor 200 turned off.

  In this case, the lower drawer described above is pulled out from the second housing 10B, and as shown in FIG. 2, the bolt 348 is loosened from the outside, the holding member 350 is removed, and the retracting surface 230 faces upward ( The pin 354 is inserted through the through hole 362 in a state of being directed to the transport path 60. Then, the holding member 350 is fixed to the side plate 302 </ b> A of the lower housing 302 from the outside using the bolts 348.

  Thereby, as shown in FIG. 1, the pin 354 is fitted into the through hole 364 formed in the composite inspection surface 236 of the reference roll 226. Even when the motor is not excited, the rotational position of the reference roll 266 is held with the retracting surface 230 facing upward (the state facing the transport path 60).

  As described above, the rotational position of the reference roll 226 is maintained by fitting the pin 354 into the through hole 364 formed in the composite inspection surface 236 of the reference roll 266 even when the power of the in-line sensor 200 is turned off. Thus, the retreating surface 230 faces the transport path 60.

  Further, by holding the rotational position of the reference roll 226 with the retreat surface 230 facing the conveyance path 60, the recording medium P is stored even when the image forming apparatus 10 is operated with the power of the inline sensor 200 turned off. It passes above the reference roll 226 while being guided by the retreat surface 230.

  Further, when the recording medium P passes above the reference roll 226, the reference roll 226 does not rotate even if the recording medium P hits the reference roll 226.

  Further, since the reference roll 226 does not rotate, it is possible to prevent the transport posture of the recording medium P from being changed due to the influence of the reference roll 226.

  In addition, since the change in the transport posture of the recording medium P is suppressed, defects such as a paper jam of the recording medium P are suppressed.

  Further, since the holding member 350 can be attached to and detached from the lower housing 302 from the outside (outside) of the lower housing 302, the rotation position of the reference roll 226 is easily held using the holding member 350.

  Moreover, the plate | board member which comprises the evacuation surface 230 is made thick so that the gravity center of the reference | standard roll 226 may be on the rotating shaft 226A seeing from a rotating shaft direction. Thereby, backlash is suppressed.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is clear to the contractor. For example, in the above-described embodiment, the pin 354 is inserted into the through hole 364 to hold the rotation position of the reference roll 226. However, the present invention is not limited to this. You may hold | maintain a rotation position by pressing a pressing member.

  Next, an example of the detection apparatus and the image forming apparatus according to the second embodiment of the present invention will be described with reference to FIG. In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 15, in the second embodiment, a holding member having a pin is not provided, and the rotating shaft is held so that the reference roll 226 is held at a position where the retracting surface 230 faces the conveyance path side. A center-of-gravity structure 390 that can determine the position of the center of gravity of the reference roll 226 with respect to 226A is provided.

  Specifically, each surface of the reference roll 226 is placed so that the center of gravity of the reference roll 226 is located below the rotation shaft 226A when viewed from the Z direction with the retracting surface 230 facing the conveyance path side. The plate thickness to be configured and the plate thickness of the rib 392 that holds each surface are determined.

  Next, an example of the detection apparatus and the image forming apparatus according to the third embodiment of the present invention will be described with reference to FIG. In addition, about the same member as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 16, the reference roll 404 according to the third embodiment is configured to rotate only in one direction (the direction of arrow J shown in FIG. 16).

  The reference roll 404 is loaded with a load that rotates in one direction due to gravity in a state where the composite inspection surface 236 is directed toward the recording medium conveyance path 60.

  Specifically, when viewed from the Z direction, the composite inspection surface 236 disposed on the opposite side to the transport path 60 and the transport path 60 are set in a parallel state (see FIG. 16). At this position, a vertical line K that passes through the center of rotation of the reference roll 404 is drawn, and a rib plate that holds each surface so that the center of gravity of the reference roll 404 is arranged on the right side (shaded side) of the vertical line K. Determine the thickness.

  With such a configuration, a load that rotates in one direction due to gravity is applied to the reference roll 404 in a state where the composite inspection surface 236 is directed toward the recording medium conveyance path 60.

  This suppresses the rotation of the reference roll 40 on the opposite side (backlash side) to the rotation direction of the reference roll 40 in a state where the composite inspection surface 236 is directed to the recording medium conveyance path 60 (reference roll). 404 position is stable).

  Further, the rotation of the reference roll 40 on the reverse side (backlash side) is suppressed, so that the position adjustment pattern 240 in the composite inspection surface 236 is prevented from moving in the conveyance direction of the recording medium P. , Variation in cash register values is suppressed.

  In addition, the rotation of the reference roll 40 on the opposite side (backlash side) is suppressed, so that the depth detection pattern 244 in the composite inspection surface 236 is prevented from moving in the conveyance direction of the recording medium P. The variation of the depth adjustment value is suppressed.

  In the first embodiment, the position of the center of gravity of the reference roll 226 is on the rotation axis. In the second embodiment, the position of the center of gravity of the reference roll 226 is lower than the rotation axis 226A. This can be selected as appropriate.

  In this embodiment, light is applied from the front side of the recording medium P. However, when a recording medium P that transmits light is used, light may be applied from the back side of the recording medium P.

  The in-line sensor 200 of the present invention is not limited to a detection device that detects an image on a recording medium, and can also be applied to a detection device that detects the shape of a recording medium.

  The in-line sensor 200 of the present invention is not limited to the detection device for the reflective recording medium, but can also be applied to a transmission recording medium detection device that illuminates from the lower housing 302 side.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 16 Image forming unit (an example of image forming means)
200 Inline sensor (an example of a detection device)
201 Detection means 204 CCD sensor (an example of light receiving means)
208 Imaging unit 212 Lamp (an example of irradiation means)
226 Reference roll (an example of opposing member)
226A Rotating shaft 228 Detection reference surface (an example of the first surface)
230 Retraction surface (an example of the second surface)
251 Motor (an example of drive means)
350 Holding member (example of convex part)
364 Through hole (an example of a recess)
390 Center of gravity structure 404 Reference roll (an example of an opposing member)

Claims (9)

An irradiation unit configured to irradiate light toward a conveyance path in which the medium is conveyed; and a light receiving unit configured to receive reflected light of light emitted from the irradiation unit, and is conveyed in the conveyance path. Detecting means for detecting an image on the medium or the medium;
When irradiating light to the medium to which the irradiating means is transported, the first surface facing the irradiating means with the medium interposed therebetween, and when not irradiating the medium to which the irradiating means is transported And a second surface facing the irradiation unit at a position further away from the irradiation unit than the first surface is provided in a phase different from the surface, and rotates about a rotation axis. An opposing member that switches between the first surface and the second surface,
A driving means that excites when a voltage is applied and drives the opposing member to rotate or stop;
Holding means for holding the rotational position of the facing member in a state where the driving means is not excited;
A detection device comprising: The holding means is
An engaging portion formed on the facing member;
An engaged portion that is detachably fixed to the apparatus main body and engages with the engaging portion;
The detection device according to claim 1. The engaging portion is a recess formed in the facing member,
The detection device according to claim 2, wherein the engaged portion is a convex portion that is fitted into the concave portion from the outside and holds the rotation of the facing member.   The thickness of the plate member constituting the second surface is increased so that the center of gravity of the opposing member is on the rotation axis when viewed from the rotation axis direction. The detection device described in 1.   The counter member rotates in only one direction, and when the first surface faces the conveyance path side, the load is applied to the counter member by gravity in the one direction side. The detection device according to any one of the above.   6. The detection apparatus according to claim 5, wherein an image for detecting a detection position where the detection means detects or a depth of focus of the detection means is formed on the first surface.   The detection device according to claim 1, wherein the opposing member holds the opposing member by gravity at a position where the second surface faces the transport path side. An irradiation unit configured to irradiate light toward a conveyance path in which the medium is conveyed; and a light receiving unit configured to receive transmitted light of light emitted from the irradiation unit, and are conveyed in the conveyance path. Detecting means for detecting an image on the medium or the medium;
When irradiating light to the medium transported by the irradiating means, a first surface facing the detecting means across the medium, and when not irradiating the medium transported by the irradiating means And a second surface facing the detection means at a position further away from the detection means than the first surface is provided in a phase different from the surface, and rotates around the rotation axis. An opposing member that switches between the first surface and the second surface,
A driving means that excites when a voltage is applied and drives the opposing member to rotate or stop;
Holding means for holding the rotational position of the facing member in a state where the driving means is not excited;
A detection device comprising: Image forming means for forming an image on the medium conveyed by the conveying means;
The detection device according to any one of claims 1 to 8, wherein an image formed on the medium or the medium is detected by the image forming unit;
An image forming apparatus comprising:

Images