JP2018106149A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can suppress an increase in size of the apparatus and suppress an increase in temperature of image detection means.SOLUTION: An image forming apparatus comprises: image detection means, such as an image detection sensor 1 that detects a fixed image on a recording medium that passes through a fixing device 108. A protective member, such as a protective glass 7 that protects the image detection means is arranged between the image detection means and recording medium. The image forming apparatus holds the protective member with a heat radiation member 10, and inhibits heat transferred from the recording medium to the protective member from being radiated by the radiation member 10 and the image detection means from being heated by the heat of the recording medium.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus.

  Conventionally, a fixing device as a heating device that heats an image on a recording medium that has been conveyed and fixes the image on the recording medium, an image detection unit that detects a fixed image on the recording medium that has passed through the fixing device, 2. Description of the Related Art An image forming apparatus is known that includes a protective member such as a protective glass that is disposed between a recording medium and an image detection unit and protects the image detection unit.

  Japanese Patent Application Laid-Open No. 2004-228561 describes the above-described image forming apparatus in which a recording medium that has passed through a fixing device is cooled by a cooling device, and then an image fixed on the recording medium is detected by the image detection unit. . After the recording medium is cooled by the cooling device, an image fixed on the recording medium is detected by the image detection means, so that the temperature of the image detection means rises due to the recording medium heated by the fixing device as a heating device. It is described that it can be suppressed.

  However, in Patent Document 1, the image forming apparatus may be increased in size.

  In order to solve the above problems, the present invention has passed a conveyance path for conveying a recording medium, an image forming unit for forming an image on the recording medium, a heating device for heating the recording medium, and the heating device. An image forming apparatus comprising: an image detecting unit that detects an image on the recording medium; and a protective member that protrudes from the lower end of the image detecting unit to the conveyance path, wherein the protective member has thermal conductivity. It is characterized by being held by a member.

  According to the present invention, it is possible to suppress an increase in the size of the apparatus and suppress an increase in the temperature of the image detection means.

1 is a schematic configuration diagram of a printer according to an embodiment. The schematic block diagram of an image detection apparatus. The figure explaining attachment to the thermal radiation member of an image detection sensor. The schematic block diagram which shows the auxiliary | assistant heat radiating member and the heat radiating member holding the image detection sensor. The figure explaining positioning of an image detection sensor. FIG. 6 is an enlarged cross-sectional view around D surrounded by a chain line in FIG. 5. The perspective view of an image detection apparatus. The schematic block diagram of the image detection apparatus which provided the auxiliary | assistant heat dissipation member in the outer wall of the heat dissipation member. The schematic perspective view of the image detection apparatus which provided the auxiliary | assistant heat dissipation member in the outer wall of the heat dissipation member. The schematic block diagram of the image detection apparatus which provided the heat conductive sheet between the guide member and the heat radiating member.

An embodiment in which the present invention is applied to an electrophotographic printer (hereinafter simply referred to as “printer”) as an image forming apparatus will be described below.
FIG. 1 is a schematic configuration diagram of a printer 100 according to the present embodiment. Symbols “C”, “M”, “Y”, and “K” in the drawing indicate members for each color of cyan, magenta, yellow, and black, respectively.

  As shown in FIG. 1, the printer 100 includes four toner image forming units 101 (C, M, Y, and K) that respectively generate cyan, magenta, yellow, and black square toner images. The four toner image forming units 101 (C, M, Y, and K) use C, M, Y, and K toners having different colors as image forming materials, but the other configurations are the same. Hereinafter, the reference numerals (C, M, Y, K) indicating the color of the toner to be used will be omitted as appropriate.

  As shown in FIG. 1, the printer 100 includes an intermediate transfer belt 107 that is an intermediate transfer body below the four toner image forming units 101. The intermediate transfer unit 120 serving as transfer means moves endlessly while stretching the intermediate transfer belt 107 by a plurality of stretching rollers. Below the intermediate transfer unit 120, a heating device is provided with a fixing device 108 as fixing means, and below the fixing device 108 is provided with paper feed trays 105 a and 105 b for accommodating transfer paper P as a recording medium. A paper portion 105 is provided. The transfer paper P is fed from the paper supply unit 105 to a transport path S for transporting the transfer paper P. The transfer sheet fed to the conveyance path S is conveyed as indicated by an arrow A toward the registration roller pair 116.

  Each toner image forming unit 101 includes a drum-shaped photoreceptor 112 as a latent image carrier, a charging device 111 as a charging unit, a developing device 113 as a developing unit, an exposure device 110 as a latent image forming unit, and the like. ing. The charging device 111 uniformly charges the surface of the photoconductor 112 that is rotated counterclockwise in FIG. The uniformly charged surface of the photoconductor 112 is exposed and scanned by laser light emitted from an exposure device 110 serving as a latent image forming unit based on image information, and an electrostatic latent image corresponding to the image information of each color is formed. Is done. The electrostatic latent image on the surface of the photoreceptor 112 of each color is developed into each color toner image by the developing device 113 using each color toner. The toner images on the surfaces of the respective photoconductors 112 are sequentially intermediate transferred onto the intermediate transfer belt 107.

  In addition to the intermediate transfer belt 107, the intermediate transfer unit 120 includes four primary transfer bias rollers 114 (C, M, Y, K), a secondary transfer backup roller 103, and the like. The intermediate transfer belt 107 is moved endlessly in the clockwise direction in FIG. 1 (the direction of arrow “B” in FIG. 1). The four primary transfer bias rollers 114 (C, M, Y, K) sandwich the intermediate transfer belt 107 moved endlessly in this manner between the four photoconductors 112 (C, M, Y, K). Thus, each primary transfer nip is formed. The four primary transfer bias rollers 114 are of a type that applies a transfer bias having a polarity (for example, plus) opposite to that of the toner to the back surface (loop inner peripheral surface) of the intermediate transfer belt 107.

  Of the plurality of rollers that stretch the intermediate transfer belt 107, all the rollers except the primary transfer bias roller 114 are electrically grounded. The intermediate transfer belt 107 sequentially passes through the primary transfer nips for C, M, Y, and K along with its endless movement, and C on the surface of the photoreceptor 112 (C, M, Y, K). , M, Y, and K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as “four-color toner image”) is formed on the intermediate transfer belt 107.

  The secondary transfer backup roller 103 sandwiches the intermediate transfer belt 107 between the secondary transfer roller 115 and forms a secondary transfer nip. The transfer paper P stored in the paper feed trays 105a and 105b is fed one by one to the transport path S by the paper feed roller, and is transported toward the secondary transfer nip by the registration roller pair 116 at a predetermined timing.

The four-color toner image formed on the intermediate transfer belt 107 is transferred to the transfer paper P at the secondary transfer nip. In the secondary transfer nip, the transfer paper P is nipped and conveyed between the intermediate transfer belt 107 and the secondary transfer roller 115 whose surfaces move in the forward direction. When the transfer paper P sent out from the secondary transfer nip passes between the rollers of the fixing device 108, the four-color toner image transferred to the surface is fixed by heat and pressure.
The transfer paper P that has passed through the fixing device 108 is cooled by the cooling roller 109 and then discharged from the transport path S onto a paper discharge tray 117 outside the casing of the printer 100.

  An operation unit 104 having a display unit and an operation panel is provided on the upper surface of the apparatus main body. Further, a reverse retransmission unit may be provided to enable double-sided printing. When performing double-sided printing, the transfer sheet after fixing is conveyed to the reverse retransmission section, the transfer sheet P is reversed and re-supplied to the registration roller pair 116, and the toner image is transferred from the intermediate transfer belt 107 to the back side of the sheet. The Thereafter, fixing is performed by the fixing device 108 as in the case of single-sided printing, and then the paper is discharged onto a paper discharge tray 117 outside the housing of the printer 100.

  Further, an image detection device 201 serving as an image detection unit that detects an image fixed on the transfer paper P is provided between the fixing device 108 and the cooling roller 109. The image detection apparatus 201 includes an image detection sensor such as a contact image sensor, and can detect image information two-dimensionally.

  In the present embodiment, the position of the fixed image on the transfer paper P passing through the image detection apparatus 201 and the image density (color tone) are detected, and the image forming conditions are corrected based on the detection result. When the image position detected by the image detection apparatus 201 is deviated from the specified position, the latent image writing timing of the exposure apparatus 110 is adjusted, or the drive start timing of the registration roller pair 116 is adjusted, thereby adjusting the image. The position is adjusted. If the image density (color tone) detected by the image detection device 201 deviates from the standard, the image density (color tone) is adjusted by adjusting the developing bias, the charging bias, the exposure amount of the exposure device 110, and the like. Adjusted.

  When printing a large number of images continuously, the image detection device 201 detects the image position and image density (color tone) of each image fixed on the transfer paper, and feeds it back to subsequent printing. To do. Thereby, when a large amount of images are continuously printed, it is possible to suppress the occurrence of image quality unevenness such as the quality of the first image being different from the quality of the last image.

  The image detection sensor includes a substrate on which a plurality of light emitting elements and a plurality of imaging elements are arranged in a straight line in the width direction of the transfer paper, and an SLA (Selfoc) as an imaging lens for forming an image on the imaging element. (Registered trademark) lens array).

  The image detection sensor is sensitive to heat. For example, when SLA rises in temperature, components are deposited on the surface, and the components deposited on the surface react with water vapor in the air to make the surface of SLA cloudy, thereby degrading optical performance. I will let you. As a result, good image detection cannot be performed. In addition, due to thermal expansion of the substrate due to heat, the position of the image pickup device may deviate from a specified position, and thus there is a possibility that good image detection may not be performed. Therefore, in order to perform good image detection, the image detection sensor is preferably suppressed to 50 ° C. or lower.

  On the other hand, in order to detect the fixed image on the transfer paper accurately and accurately, there is a restriction that the distance between the image detection sensor and the transfer paper P must be kept at several millimeters, which is heated by the heat of the fixing device. It is necessary to dispose the image detection sensor at a distance close to the transfer paper. The transfer paper heated by the heat of the fixing device exceeds 100 ° C., and when the transfer paper heated by the fixing device passes the image detection position of the image detection sensor, the image detection sensor is heated, The temperature of the detection sensor rises. When a large amount of images are continuously printed, the temperature of the image detection sensor may exceed 50 ° C., and there is a possibility that good image detection cannot be performed.

  A protective glass serving as a protective member for protecting the image detection sensor is disposed between the image detection sensor and the transfer paper to be transported, and heat of the transfer paper is conducted to the image detection sensor through the protective glass. The temperature of the image detection sensor is increased. Therefore, in the present embodiment, the protective glass is held by the heat radiating member, and the heat transferred from the protective glass to the image detection sensor is reduced by radiating the heat of the protective glass by the heat radiating member. The rise was suppressed. Hereinafter, it demonstrates concretely using drawing.

FIG. 2 is a schematic configuration diagram of the image detection apparatus 201.
As shown in FIG. 2, the image detection apparatus 201 includes an image detection sensor 1. The image detection sensor 1 includes a plurality of imaging elements 3 such as photodiodes, a plurality of light emitting elements 4 such as LEDs, an SLA (selfoc lens array) 2 that is an imaging lens for forming an image on the imaging element, and the like. ing. The plurality of imaging elements 3 and the plurality of light emitting elements 4 are arranged on the substrate 5 side by side in the width direction of the transfer paper (direction orthogonal to the paper surface). The SLA 2 is held by the holder 6.

  A protective glass 7 serving as a transparent protective member for protecting the image detection sensor 1 is disposed between the image detection sensor 1 and the transfer paper being conveyed. The protective glass 7 is held by the heat radiating member 10, and the image detection sensor 1 is housed in the heat radiating member 10. The heat radiating member 10 has a sensor holding unit 11 that holds the image detection sensor 1, and the image detection sensor 1 is held by the sensor holding unit 11. Further, the heat radiating member 10 has a substantially box shape with an upper portion opened in the figure, and a cover member 31 is attached to the upper portion.

  The heat radiating member 10 is a heat conductive member, and the heat conductive member is one having a heat conductivity of 60 [W / (m · K)] or more. In the present embodiment, it is preferable to use a heat conductive member having a thermal conductivity of 200 [W / (m · K)] or higher, and a heat conductive member of 400 [W / (m · K)] or higher is used. Is more preferable. In the present embodiment, the heat radiating member is made of aluminum (thermal conductivity is 200 [W / (m · K)] or more).

  The heat of the transfer paper P heated by the fixing device first moves to the protective glass 7 when passing through the image detection position of the image detection sensor 1. The heat that has moved to the protective glass 7 can be suppressed to increase in the temperature of the protective glass 7 by moving to the heat radiating member 10 that is made of a heat conductive member that holds the protective glass. The heat radiating member 10 has a substantially box shape, and has side walls extending in four directions in a direction perpendicular to the paper surface of the transfer paper. Since the transfer paper heated by the fixing device passes near the lower transfer paper in the figure, the ambient temperature is high, but the upper ambient temperature in the figure is lower than the lower one in the figure. It is low enough. Since the heat radiating member 10 is composed of a heat conductive member as described above, the heat that has moved from the protective glass 7 quickly moves to the upper side in the drawing having a low ambient temperature and radiates heat. Thereby, even when a large amount of images are continuously printed, the heat of the protective glass 7 heated by the transfer paper P can be favorably transferred to the heat radiating member 10, and the temperature rise of the protective glass 7 can be suppressed. Therefore, it is possible to suppress heat from moving from the protective glass 7 to the image detection sensor 1, and to suppress an increase in temperature of the image detection sensor 1. As a result, it is possible to suppress thermal deformation such as the SLA of the image detection sensor 1 becoming cloudy or the thermal expansion of the substrate 5 holding the light emitting element 4 or the image pickup element 3, thereby achieving good image detection. It can be carried out.

  The heat radiating member 10 is provided with guide members 41 and 42 for guiding the transfer paper P being conveyed. The guide surfaces for guiding the transfer paper of the guide members 41 and 42 protrude from the protective glass 7 toward the transfer paper conveyance side, and guide the transfer paper P so as not to contact the protective glass. Thereby, it can suppress that the protective glass 7 is rubbed with the transfer paper P in conveyance, and the surface is damaged, or the dirt adhering to the transfer paper attaches to the protective glass. As a result, the image fixed on the transfer paper by the image detection sensor can be detected well over time.

  Further, by guiding the transfer paper P so that it does not come into contact with the protective glass 7, it is possible to suppress the heat from directly transferring from the transfer paper to the protective glass 7, and to suppress the temperature rise of the protective glass 7. Can do.

  Further, by providing the guide member on the front side in the transport direction and the rear side in the transport direction with respect to the protective glass 7, it is possible to suppress the transfer paper entering the image detection position from coming into contact with the protective glass 7, and the image. It is possible to suppress the transfer paper that has passed the detection position from coming into contact with the protective glass 7.

  In the present embodiment, the guide members 41 and 42 are made of SUS. By forming with SUS, it is possible to prevent the surface from being damaged by the fixed image on the transfer paper. Further, since the guide members 41 and 42 are in contact with the transfer paper, heat is directly transferred from the transfer paper, and the temperature of the guide members 41 and 42 is increased. The heat that has moved to the guide members 41 and 42 moves from the portion of the guide members 41 and 42 that contacts the heat radiating member 10 to the heat radiating member 10, and the temperature around the heat retaining member 10 that holds the protective glass 7 rises. As a result, the amount of heat transferred from the protective glass 7 to the heat radiating member 10 is reduced, and the temperature rise of the protective glass may not be sufficiently suppressed. Therefore, it is preferable that the guide members 41 and 42 are not in contact with the heat radiating member 10 except for an attachment portion attached to the heat radiating member 10. Thereby, it can suppress that a heat moves from the guide members 41 and 42 to the heat radiating member 10, and can suppress that the moving amount of the heat from the protective glass 7 to the heat radiating member 10 reduces.

  Further, the guide members 41 and 42 are made of a material having a low thermal conductivity, or the guide members 41 and 42 are attached to the heat radiating member 10 via a material having a low thermal conductivity. , 42 is preferably prevented from moving to the heat radiating member.

  In the present embodiment, the guide members 41 and 42 are attached to the side wall portions provided at both ends in the transfer paper width direction, and the attachment positions where the guide members 41 and 42 are attached to the heat radiating member are set to the positions of the heat radiating members. The position is away from the place where the protective glass 7 is held. Thereby, it can suppress that the vicinity which hold | maintains the protective glass 7 of the heat radiating member 10 rises in temperature by the heat which has moved from the guide member.

  Further, by attaching the guide members 41 and 42 to members other than the heat radiating member 10, it is possible to favorably suppress the heat of the guide members 41 and 42 from moving to the heat radiating member 10. However, if each guide member 41, 42 is attached to a part other than the heat radiating member 10 that holds the protective glass 7, the positional accuracy between the guide member 41, 42 and the protective glass 7 is deteriorated due to accumulation of component tolerances and the like. As a result, the transfer paper may not be guided so that the transfer paper does not contact the protective glass 7. For this reason, the guide members 41 and 42 are preferably attached to the heat radiating member 10.

  In addition, an auxiliary heat radiating member 21 that assists the heat radiating of the heat radiating member 10 is provided inside the heat radiating member 10. The auxiliary heat radiating member 21 is made of aluminum like the heat radiating member, and has a heat receiving portion 25 on the left side in the drawing. The heat receiving portion 25 is radiated through the first heat conductive sheet 12. 10 is thermally connected. On the right side in the figure, there is an attachment portion 24, which is attached to the attached portion 18 of the heat radiating member 10 with screws. The auxiliary heat radiating member 21 is formed with a heat radiating portion 21a composed of a plurality of fins extending in the width direction of the transfer paper (direction perpendicular to the paper surface). Part of the heat of the heat radiating member 10 moves to the auxiliary heat radiating member 21 via the first heat conductive sheet 12 and is radiated from the heat radiating portion 21 a of the auxiliary heat radiating member 21. Thereby, compared with what dissipates heat only with the heat radiating member 10, heat dissipation efficiency can be improved and the temperature rise of the heat radiating member 10 can be suppressed. As a result, the heat of the protective glass can be favorably moved to the heat radiating member 10, and the temperature rise of the protective glass can be suppressed. As a result, the heat moving from the protective glass 7 to the image detection sensor 1 can be reduced, and the temperature rise of the image detection sensor 1 can be suppressed.

  Further, the auxiliary heat radiating member 21 is thermally connected to the substrate 5 of the image detection sensor 1 through the second heat conductive sheet 22. The substrate 5 of the image detection sensor 1 has an image processing chip 5a (see FIG. 3) that processes an image captured by the imaging device 3, and this image processing chip generates heat. In addition, since the light emitting element 4 such as an LED held by the substrate 5 also generates heat, the substrate 5 may rise in temperature and may be thermally deformed, for example, the substrate 5 may thermally expand. When the substrate 5 is thermally deformed, the position of the imaging element held on the substrate may be shifted from a specified position, and the focal position may change. As a result, the image picked up by the image sensor 3 may be out of focus and the image detection accuracy may be reduced. Further, the heat of the substrate 5 moves to the SLA 2 and raises the temperature of the SLA 2, so that the surface of the SLA 2 may become clouded.

  In the present embodiment, the heat of the substrate 5 moves to the auxiliary heat radiating member 21 via the second heat conductive sheet 22. And the heat | fever of the board | substrate 5 which moved to the auxiliary | assistant heat radiating member 21 is radiated by the thermal radiation part 21a. Thereby, the temperature rise of the board | substrate 5 can be suppressed, it can suppress that the board | substrate 5 deform | transforms with a heat | fever, and the fall of image detection accuracy can be suppressed. In addition, the temperature of the SLA 2 can be prevented from rising due to the heat of the substrate 5, and the surface of the SLA 2 can be prevented from becoming clouded.

  Moreover, since the auxiliary | assistant heat radiating member 21 is comprised with aluminum and is electroconductive, it is preferable to make the said 2nd heat conductive sheet 22 into insulation. By making the 2nd heat conductive sheet 22 insulative, the electric current which flows into the auxiliary | assistant heat radiating member through the board | substrate 5 can be prevented from flowing into the auxiliary | assistant heat radiating member 21 via a 2nd heat conductive sheet.

FIG. 3 is a diagram illustrating the attachment of the image detection sensor 1 to the heat radiating member 10.
As shown in FIG. 3, the heat radiating member 10 is provided with sensor holding portions 11 that hold the box-shaped image detection sensors 1 at two locations in the width direction of the transfer paper (left and right in the drawing). Positioning portions 15 for positioning the image detection sensor 1 in a direction orthogonal to the image forming surface of the transfer paper (a direction orthogonal to the paper surface) are provided at both ends of the sensor holding unit 11 in the transfer paper width direction. Then, the two image detection sensors 1 are fitted into the corresponding sensor holding portions 11 and held by the heat radiating member 10 side by side in the width direction of the transfer paper.

  On the surface opposite to the surface on which the image sensor or light emitting element of the substrate 5 of the image detection sensor 1 is mounted (hereinafter referred to as the back surface of the substrate), images taken by the image sensor at two locations in the transfer paper width direction are processed. An image processing chip 5a is mounted.

FIG. 4 is a schematic configuration diagram showing the auxiliary heat radiating member 21 and the heat radiating member 10 holding the image detection sensor 1.
As shown in FIG. 4, four leaf springs 23 are attached to the opposing surface of the auxiliary heat radiating member 21 facing the substrate 5 of the image detection sensor 1. Each leaf spring 23 is provided on the opposing surface of the auxiliary heat radiating member 21 facing the substrate 5 of the image detection sensor so as to contact the end of the substrate 5 in the transfer paper width direction, as indicated by a chain line X in the figure. . In addition, a second heat conductive sheet 22 is attached to the opposite surface of the auxiliary heat radiating member 21 that faces the substrate 5. In FIG. 4, the second heat conductive sheet 22 is provided so that the second heat conductive sheet 22 is in close contact with almost the entire back surface of the substrate 5, but only in contact with only the image processing chip 5 a that generates a large amount of heat. The heat of the image processing chip 5a may be moved to the auxiliary heat radiating member.

  Moreover, the 1st heat conductive sheet 12 is affixed on the lower side wall of the heat radiating member 10 in the figure. The first heat conductive sheet 12 is made of an elastic material such as acrylic rubber or silicone rubber, and is crushed by the auxiliary heat radiating member 21 so as to be in close contact with the heat receiving portion 25 of the auxiliary heat radiating member 21, and the heat of the heat radiating member 10 is radiated as auxiliary heat. Heat is transferred to the member 21 satisfactorily. The auxiliary heat radiating member 21 is assembled by sliding the heat receiving portion 25 against the surface of the first heat conducting sheet 12 while crushing the first heat conducting sheet 12 with the heat receiving portion 25. However, since the first heat conductive sheet 12 is made of an elastic body such as acrylic rubber or silicone rubber and has poor sliding properties, the heat receiving portion 25 does not slide smoothly on the surface of the first heat conductive sheet 12, 1 The heat conductive sheet 12 might peel off from the heat radiating member 10.

  Therefore, in this embodiment, the sliding sheet 13 is affixed on the surface of the first heat conductive sheet 12. The sliding sheet 13 is a member having a lower coefficient of friction with the heat receiving portion 25 than the first heat conductive sheet, and in this embodiment, a PET film is attached. Thereby, when the auxiliary heat radiating member 21 is assembled to the heat radiating member 10, it is possible to suppress the first heat conductive sheet 12 from being peeled off from the heat radiating member 10.

  The auxiliary heat radiating member 21 is attached to the heat radiating member 10 by passing a screw through a through hole 24 a provided in the mounting portion 24 of the auxiliary heat radiating member 21 and screwing the screw into the screw hole of the attached portion 18 of the heat radiating member 10. It is done. When the auxiliary heat radiating member 21 is attached to the heat radiating member 10, the second heat conductive sheet 22 is crushed and adheres closely to the back surface of the substrate 5.

  In addition, the code | symbol 16 of FIG. 4 is a communicating hole for letting the duct for flowing air in the heat radiating member 10 mentioned later passing.

FIG. 5 is a diagram illustrating the positioning of the image detection sensor 1, and FIG. 6 is an enlarged cross-sectional view of the vicinity of D surrounded by a chain line in FIG.
When the auxiliary heat radiating member 21 is attached to the heat radiating member 10, the leaf springs 23 press both ends of the substrate 5 in the transfer paper width direction toward the protective glass. As a result, the holder 6 of the image detection sensor 1 abuts against the positioning portion 15 of the heat radiating member 10 and the image detection sensor 1 is positioned in a direction perpendicular to the image forming surface of the transfer paper. Thereby, the focus of the image sensor 3 can be adjusted to the transfer area of the transfer paper, and the image of the transfer paper can be detected with high accuracy.

  Moreover, when the heat radiated by the heat radiating portion 21 a of the auxiliary heat radiating member 21 enters the heat radiating member 10, the temperature of the heat radiating member 10 rises, the heat radiating efficiency of the protective glass 7 decreases, and the heat radiated from the auxiliary heat radiating member 21. Efficiency is also reduced. Therefore, it is preferable to flow air inside the heat radiating member 10 to exhaust the heated air in the heat radiating member 10 and to cool the auxiliary heat radiating member 21 with air.

FIG. 7 is a perspective view of the image detection apparatus 201.
As shown in FIG. 7, a communication hole 16 through which the duct 52 passes is provided in the heat dissipation member 10 at one end in the transfer paper width direction of the heat dissipation member 10, and the duct 52 is inserted into the communication hole 16. 52 air outlets are provided to face the heat radiating portion 21a of the auxiliary heat radiating member. A blower port of the sirocco fan 51 is attached to the air intake port of the duct 52. On the other hand, an exhaust lid 32 provided with a plurality of exhaust ports 32a is attached to the other end of the heat radiating member 10 in the transfer paper width direction.

  The air taken in by the sirocco fan 51 moves through the duct 52 into the heat radiating member 10 and is ejected from the air ejection port of the duct 52. Then, as indicated by an arrow A in the figure, the air flows toward the other end in the transfer paper width direction, and the heat radiating portion 21a of the auxiliary heat radiating member 21 is air-cooled. The air whose temperature has risen due to heat removal from the heat radiating portion 21 a is exhausted from a plurality of exhaust ports 32 a of the exhaust lid 32 provided at the other end in the transfer paper width direction of the heat radiating member 10. Thereby, the temperature rise of the auxiliary | assistant heat radiating member 21 can be suppressed, and the heat | fever of a board | substrate and the heat radiating member 10 can be thermally radiated favorably.

  Further, since the temperature inside the image forming apparatus is higher than the outside air due to heat generated from various apparatuses, the outside air is preferable as the air that the sirocco fan 51 takes in. Therefore, it is preferable to provide an intake port in the housing of the image forming apparatus and connect the intake port to the air intake port of the sirocco fan 51 to take in outside air.

  For example, when the transfer paper is thick paper or when the image has a high image area ratio, the amount of heat required for fixing increases, so the temperature of the fixing device is increased. As a result, the temperature of the transfer paper that has passed through the fixing device increases, and the temperature of the image detection sensor tends to increase. Therefore, in such a case, it is preferable to increase the flow rate of the air flowing into the heat radiating member 10. On the other hand, if only one image is formed, the image detection sensor 1 is not heated to 50 ° C. or higher without air cooling the auxiliary heat radiating member. Therefore, in such a case, for example, it is preferable to stop the driving of the sirocco fan 51.

  Therefore, in the present embodiment, the sirocco fan 51 is connected to the control unit 90 as control means, and the control unit 90 controls the flow rate of the air flowing to the heat radiating member 10. Accordingly, the flow rate of air flowing to the heat radiating member 10 can be controlled by controlling the sirocco fan 51 by the control unit 90 based on the thickness of the transfer paper, the image area ratio, and the number of sheets to be printed. Thereby, while suppressing the temperature rise of the favorable image detection sensor 1, it becomes possible to reduce noise, such as a wind noise emitted from a sirocco fan, and the electric power supply to a sirocco fan.

  In the present embodiment, the auxiliary heat radiating member 21 is provided with a fin-shaped heat radiating portion 21a, and the heat radiating portion 21a is air-cooled to cool the auxiliary heat radiating member 21. It may be cooled. Alternatively, the auxiliary heat radiating member 21 may be eliminated, and the heat radiating member 10 may be cooled by a liquid cooling device to increase the heat radiating efficiency of the heat radiating member 10.

FIG. 8 is a schematic configuration diagram of an image detection device in which the auxiliary heat radiating member 21 is provided on the outer wall of the heat radiating member 10, and FIG. 9 is an image detection device in which the auxiliary heat radiating member 21 is provided on the outer wall of the heat radiating member 10. It is a schematic perspective view shown.
As shown in FIGS. 8 and 9, the auxiliary heat radiating member 21 may be provided on the outer wall of the heat radiating member 10. Even in such a configuration, the heat of the heat radiating member 10 can be moved to the auxiliary heat radiating member and radiated by the heat radiating portion 21 a of the auxiliary heat radiating member 21. Thereby, the temperature rise of the thermal radiation member 10 can be suppressed and the heat | fever of a protective glass can be moved to the thermal radiation member 10 favorably. Also in such a configuration, it is preferable to cool the heat radiating portion by air-cooling the heat radiating portion.

  Moreover, in the above-mentioned, by suppressing that heat transfers from the guide members 41 and 42 to the heat radiating member 10, it suppresses that the movement amount of the heat from the protective glass 7 to the heat radiating member 10 reduces, and the protective glass 7 The temperature rise is suppressed. However, depending on the configuration of the apparatus and the like, it may be more probable that heat is actively released from the guide members 41 and 42 to the heat radiating member 10, and the transfer paper is actively deprived of heat by the guide members 41 and 42. 7 may be suppressed, and the temperature rise of the protective glass 7 may be suppressed.

FIG. 10 is a schematic configuration diagram of an image detection apparatus in which a heat conductive sheet is provided between the guide members 41 and 42 and the heat radiating member 10 so that the heat of the guide members 41 and 42 is actively released to the heat radiating member 10. It is.
As shown in FIG. 10, the guide member 41 and the heat radiating member 10 are in close contact with each other, and the third heat conductive sheet 43 that moves the heat of the guide member 41 to the heat radiating member 10, and the guide member 42 and the heat radiating member 10 are in close contact with each other. The fourth heat conductive sheet 44 moves the heat of the guide member 42 to the heat radiating member 10. Thereby, part of the heat of the guide member 41 moves to the heat radiating member 10 through the third heat conductive sheet 43 and is radiated from the heat radiating member 10. Further, part of the heat of the guide member 42 moves to the heat radiating member 10 through the fourth heat conductive sheet 44 and is radiated from the heat radiating member 10. Furthermore, a part of the heat of the guide members 41 and 42 moved to the heat radiating member 10 moves to the auxiliary heat radiating member 21 via the first heat conductive sheet 12 and is radiated from the auxiliary heat radiating member. As a result, the temperature rise of the guide members 41 and 42 can be suppressed, and the heat of the transfer paper can be satisfactorily taken away by the guide members 41 and 42. Therefore, the transfer paper can be cooled, and the amount of heat transferred from the transfer paper to the protective glass 7 can be reduced. Thereby, the temperature rise of the protective glass 7 can be suppressed, the heat which moves from the protective glass 7 to the image detection sensor 1 can be reduced, and the temperature rise of the image detection sensor 1 can be suppressed.

  In the above description, the fixing device is used as the heating device. However, the present invention is not limited to this, and any device that heats the recording medium may be used. For example, examples of the heating device include a drying device that heats a recording medium and dries ink ejected onto the recording medium in an inkjet recording apparatus that is an image forming apparatus.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect 1)
A conveyance path for conveying a recording medium such as transfer paper P, an image forming unit (in this embodiment, four toner image forming units 101, an intermediate transfer unit 120, etc.) for forming an image on the recording medium, and the recording A heating device such as a fixing device 108 that heats the medium, an image detection unit such as an image detection sensor 1 that detects an image on the recording medium that has passed through the heating device, and the transport path from the lower end of the image detection unit The protective member is held by a heat conductive member such as the heat radiating member 10.
According to this, as described in the embodiment, the protective member such as the protective glass 7 disposed between the image detection unit such as the image detection sensor 1 and the recording medium such as the transfer paper P is replaced with the heat radiating member 10 or the like. By holding by the heat conductive member, when the recording medium heated by the fixing device 108 passes through the image detection position of the image detecting means, the heat transferred from the recording medium to the protection member is radiated by the heat conductive member. be able to. As a result, the image detection means can be prevented from being heated by the heat of the recording medium, and the temperature rise of the image detection means can be suppressed without providing a cooling device for cooling the recording medium. An increase in size can be suppressed.

(Aspect 2)
In the aspect 1, the auxiliary heat radiation member 21 that assists the heat radiation of the heat conductive member such as the heat radiation member 10 is provided.
According to this, as described in the embodiment, the heat conductive member such as the heat radiating member 10 and the auxiliary heat radiating member 21 can radiate heat from the protective member such as the protective glass 7 and are protected by the heat conductive member. The heat radiation efficiency can be increased as compared with the member that radiates the heat of the member. Thereby, the temperature rise of a heat conductive member can be suppressed and the heat of protective members, such as the protective glass 7, can be favorably moved to a heat conductive member. Thereby, it is possible to satisfactorily suppress the image detection unit from being heated by the heat of the recording medium, and it is possible to suppress the temperature rise of the image detection unit.

(Aspect 3)
In the aspect 2, the auxiliary heat radiating member 21 receives heat from the substrate 5 of the image detection means such as the image detection sensor 1 to radiate heat.
According to this, as explained in the embodiment, it is possible to suppress the temperature of the substrate 5 from rising due to the heat generated by the substrate 5 of the image detection means such as the image detection sensor 1, and the substrate 5 is thermally expanded. Can be suppressed. As a result, it is possible to suppress the occurrence of problems such as the image sensor provided on the substrate 5 being displaced from the specified position and the fixed image on the recording medium such as transfer paper imaged by the image sensor being out of focus. . Further, the temperature of the imaging lens such as the SLA 2 of the image detection means can be suppressed from increasing due to the heat of the substrate 5. As a result, it is possible to suppress occurrence of a situation in which components are deposited on the surface from the imaging lens and the deposited components react with water vapor to cause the lens surface to become cloudy. Therefore, good image detection can be performed.

(Aspect 4)
In the aspect 3, the auxiliary heat radiating member 21 includes a pressing unit such as a leaf spring 23 that presses the positioning unit 15 that positions the image detection unit such as the image detection sensor 1.
According to this, the auxiliary heat radiating member 21 can also be used as a pressing mechanism that presses the positioning unit 15 that positions the image detecting means such as the image detection sensor 1, and the auxiliary heat radiating member 21 and the pressing mechanism are provided respectively. The number of parts can be reduced as compared with the device, and the cost of the apparatus can be reduced.

(Aspect 5)
In the aspect 3 or 4, the second heat conductive sheet 22 that is in close contact with the substrate 5 of the image detecting means such as the image detection sensor 1 and the auxiliary heat radiating member 21 and moves the heat of the substrate 5 to the auxiliary heat radiating member 21. The substrate has a heat conductive member.
Since the substrate 5 and the auxiliary heat radiating member 21 are rigid bodies and are not completely smooth surfaces, the entire surface of the substrate cannot be brought into close contact with the auxiliary heat radiating member 21, and a gap (air layer) is inevitably formed. There is a risk that efficient heat transfer to the auxiliary heat radiating member 21 cannot be performed.
However, in the fifth aspect, since there is a substrate heat conducting member such as the second heat conducting sheet 22 in close contact with the substrate 5 of the image detecting means and the auxiliary heat radiating member 21, either the substrate 5 of the image detecting means or the auxiliary heat radiating member 21 is used. In addition, efficient heat transfer from the substrate 5 to the auxiliary heat radiating member 21 can be performed via the heat conducting member that is in close contact therewith. Thereby, the temperature rise of a board | substrate can be suppressed favorably.

(Aspect 6)
In Aspect 5, the substrate heat conducting member such as the second heat conducting sheet 22 is insulative.
According to this, as described in the embodiment, it is possible to prevent the current flowing in the substrate 5 from flowing to the auxiliary heat radiating member 21 via the heat conductive member such as the second heat conductive sheet 22.

(Aspect 7)
In any one of the aspects 2 to 6, the first heat conductive sheet 12 that is in close contact with the heat conductive member such as the heat radiating member 10 and the auxiliary heat radiating member 21 and moves the heat of the heat radiating member 10 to the auxiliary heat radiating member 21 The second thermal conductive member.
The heat conductive member such as the heat radiating member 10 and the auxiliary heat radiating member 21 are rigid bodies and are not completely smooth surfaces. An air layer) is formed, and efficient heat transfer from the heat conductive member to the auxiliary heat radiating member 21 is impossible.
Therefore, in the aspect 7, since the heat conductive member such as the heat radiating member 10 and the second heat conductive member such as the first heat conductive sheet 12 that is in close contact with the auxiliary heat radiating member 21 are provided, the heat conductive member and the auxiliary heat radiating member are provided. Efficient heat transfer from the heat conductive member to the auxiliary heat radiating member 21 can be performed via the second heat conductive member in close contact with any member 21. Thereby, the temperature rise of a heat conductive member can be suppressed and heat can be moved to the heat radiating member 10 favorably for protective members, such as the protective glass 7. FIG.

(Aspect 8)
In the aspect 7, the second heat conductive member such as the first heat conductive sheet 12 is any one of the heat conductive members such as the auxiliary heat radiating member 21 and the heat radiating member 10 (in this embodiment, the heat radiating member 10). The contact portion that is attached to the other member and made of a sheet-like member such as the sliding sheet 13 having a lower coefficient of friction with the other member than the second heat conductive member.
According to this, when the other member (the auxiliary heat radiating member 21 in this embodiment) is attached so as to slide with the second heat conductive member such as the first heat conductive sheet 12, the second member is attached. The surface of the heat conductive member can be smoothly slid, and the second heat conductive member can be prevented from being peeled off from one member (the heat dissipating member 10 in this embodiment).

(Aspect 9)
In any one of Aspects 2 to 8, a cooling means (in the present embodiment, composed of a sirocco fan 51, a duct 52, etc.) for cooling the auxiliary heat radiating member 21 is provided.
According to this, as explained using FIG. 7, the temperature increase of the auxiliary heat radiating member 21 can be suppressed, and the heat that has moved from the heat radiating member 10 can be radiated well.

(Aspect 10)
Aspect 9 includes control means such as a control unit 90 for controlling the cooling means (in this embodiment, the sirocco fan 51, the duct 52, etc.).
According to this, as described with reference to FIG. 7, the cooling unit can be controlled based on the temperature of the transfer paper conveyed to the image detection position where the image detection unit detects the image, and the like. The temperature rise of the image detection means can be suppressed, and the necessary minimum cooling can be suppressed, and the power consumption of the apparatus can be suppressed.

(Aspect 11)
In any one of aspects 1 to 10, the recording medium such as transfer paper that passes through the image detection position of the image detection unit such as the image detection sensor 1 is not in contact with a protective member such as the protective glass 7. Guide members 41 and 42 for guiding are provided, and the guide member is attached to the thermally conductive member.
According to this, as described in the embodiment, by attaching the guide member to the heat conductive member such as the heat radiating member 10 that holds the protective member, the stacking of the component tolerance or the like can be minimized, and the protective member and the guide member Can be prevented from deviating from the prescribed relationship. Thereby, it can guide so that a favorable recording medium may not contact a protection member, and the contamination of a protection member and a temperature rise can be suppressed.

(Aspect 12)
In the aspect 11, the heat radiating member 10 is not in contact with the guide members 41 and 42 except for the attachment portion attached to the heat conductive member such as the heat radiating member 10.
According to this, as described in the embodiment, the heat that heats the guide members 41 and 42 moves to the heat conductive member such as the heat radiating member 10 such that the transfer paper contacts the guide members 41 and 42. Can be suppressed. Thereby, it can suppress that a heat conductive member raises a temperature, heat of protection members, such as protective glass 7, can be moved to a heat conductive member favorably, and a temperature rise of a protection member is controlled. be able to.

(Aspect 13)
In the aspect 11, the third heat conductive sheet 43 and the third heat conductive sheet 43 which are in close contact with the guide members 41 and 42 and the heat conductive member such as the heat radiating member 10 and move the heat of the guide members 41 and 42 to the heat conductive member. 4 It has a guide heat conductive member such as a heat conductive sheet 44.
According to this, as described in the embodiment, the heat of the guide members 41 and 42 can be moved to the heat conductive member such as the heat radiating member 10 via the guide heat conductive member. Temperature rise can be suppressed. Thus, the heat of the recording medium such as transfer paper can be satisfactorily taken away by the guide members 41 and 42, and the recording medium can be cooled well by the guide members 41 and 42. Thereby, the amount of heat transferred from the recording medium to the protective member such as the protective glass 7 can be reduced, and the temperature rise of the protective member can be suppressed.

(Aspect 14)
In any one of the aspects 11 to 13, the guide member is provided before and after the conveyance direction of the recording medium such as the transfer paper P with respect to the protection member such as the protection glass 7.
According to this, as described in the embodiment, the recording medium such as transfer paper that enters the image detection position where the image detection unit such as the image detection sensor 1 detects the image contacts the protection member such as the protection glass 7. And the contact of the recording medium that has passed the image detection position with the protective member can be suppressed.

(Aspect 15)
In any one of aspects 1 to 14, the heat conductive member is a metal.
According to this, the heat of the protective member such as the protective glass 7 can be favorably moved to the heat conductive member such as the heat radiating member 10 and can be radiated by the heat conductive member.

1: Image detection sensor 2: SLA
3: Image sensor 4: Light emitting element 5: Substrate 5a: Image processing chip 6: Holder 7: Protective glass 10: Heat radiating member 11: Sensor holding part 12: First heat conductive sheet 13: Sliding sheet 15: Positioning part 16: Communication hole 18: Mounted portion 21: Auxiliary heat radiating member 21a: Heat radiating portion 22: Second heat conductive sheet 23: Leaf spring 24: Mounting portion 24a: Through hole 25: Heat receiving portion 31: Cover member 32: Exhaust lid 32a: Exhaust Ports 41 and 42: Guide member 43: Third thermal conductive sheet 44: Fourth thermal conductive sheet 51: Sirocco fan 52: Duct 90: Control unit 100: Printer 108: Fixing device P: Transfer paper S: Conveyance path

Japanese Patent No. 4983813

Claims (15)

A conveyance path for conveying the recording medium;
An image forming unit for forming an image on the recording medium;
A heating device for heating the recording medium;
Image detecting means for detecting an image on the recording medium that has passed through the heating device;
An image forming apparatus comprising: a protective member that protrudes from the lower end of the image detection unit to the conveyance path;
The image forming apparatus, wherein the protective member is held by a heat conductive member. The image forming apparatus according to claim 1.
An image forming apparatus comprising an auxiliary heat radiating member for assisting heat radiation of the heat conductive member. The image forming apparatus according to claim 2.
The auxiliary heat radiating member radiates heat by receiving heat of the substrate of the image detecting means. The image forming apparatus according to claim 3.
The image forming apparatus according to claim 1, wherein the auxiliary heat radiating member includes a pressing unit that presses a positioning unit that positions the image detecting unit. The image forming apparatus according to claim 3 or 4, wherein:
An image forming apparatus, comprising: a substrate heat conduction member that is in close contact with the substrate of the image detection unit and the auxiliary heat dissipation member and moves heat of the substrate to the auxiliary heat dissipation member. The image forming apparatus according to claim 5.
The image forming apparatus, wherein the substrate heat conducting member is insulative. The image forming apparatus according to any one of claims 2 to 6,
An image forming apparatus comprising: a second heat conductive member that is in close contact with the heat conductive member and the auxiliary heat radiating member and moves heat of the heat conductive member to the auxiliary heat radiating member. The image forming apparatus according to claim 7.
The second heat conductive member is attached to one of the auxiliary heat radiating member and the heat conductive member, and a contact portion in contact with the other member is defined as the second heat conductive member. An image forming apparatus comprising a sheet-like member having a lower coefficient of friction with the other member. The image forming apparatus according to any one of claims 2 to 8,
An image forming apparatus comprising cooling means for cooling the auxiliary heat radiating member. The image forming apparatus according to claim 9.
An image forming apparatus comprising control means for controlling the cooling means. The image forming apparatus according to claim 1,
A guide member that guides the recording medium so that the recording medium that passes through the image detection position of the image detection unit does not contact the protection member;
An image forming apparatus, wherein the guide member is attached to the thermally conductive member. The image forming apparatus according to claim 11.
An image forming apparatus, wherein the guide member is not in contact with the heat conductive member except for a mounting portion attached to the heat conductive member. The image forming apparatus according to claim 11.
An image forming apparatus comprising: a guide heat conductive member that is in close contact with the guide member and the heat conductive member and moves heat of the guide member to the heat conductive member. The image forming apparatus according to claim 11,
An image forming apparatus, wherein the guide member is provided before and after the protective member in the conveyance direction of the recording medium. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the heat conductive member is a metal.

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