Image-forming device

Abstract

To keep precision for detecting a temperature of a fixing device while simplifying the configuration of the fixing device.SOLUTION: An image-forming device 1 provides a thermopile hole 35 for connecting a heat-insulating duct internal space 32 and the side of a fixing unit 17 in a direction that opposes a thermopile section 60, and a holding member 42 for holding the thermopile section 60 supported by a heat-insulating duct rear sideplate 30b in the heat-insulating duct internal space 32, the holding member 42 is provided between an air path breaking ridge line 50 and a duct joining surface 44S formed continuously from the side of an exhaust fan 23 to the side of an intake fan 22 relative to the thermopile hole 35, and the holding member 42 and the heat-insulating duct rear sideplate 30b in the side of the intake fan 22 relative to the thermopile section 60, and a holder ventilation space 52 and a cover ventilation space 59 that connects the heat-insulating internal space 32 and the thermopile hole 35, and branches cooling air Ca taken in by the intake fan 22 and allows the cooling air to go toward the thermopile hole 35 are formed.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus, and is suitable for application to image forming apparatuses such as copying machines and printers. [Background technology]

[0002] Conventionally, a widely used image forming apparatus is one in which an image is printed by irradiating the surface of a photosensitive drum in an image forming unit with light from a head unit having an exposure head that emits exposure light emitted from an LED (Light Emitting Diode) chip, which is a light emitting element, onto the surface of the photosensitive drum, thereby forming an electrostatic latent image on the surface of the photosensitive drum, and then by attaching a developer to the electrostatic latent image to develop a developer image, which is then transferred to a medium such as paper, and then the developer image is fixed to the medium by a fixing device.

[0003] In such image forming devices, an insulated duct is provided between the image forming unit and the fixing unit, and air is taken in from outside the image forming device by an intake fan, passed through the insulated duct, and exhausted from inside the image forming device to the outside by an exhaust fan, thereby preventing the heat generated by the fixing unit from being transmitted to the image forming unit and maintaining print quality (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-221279 Summary of the Invention [Problem to be solved by the invention]

[0005] In such an image forming apparatus, it is desirable to simplify the configuration of the fixing unit while maintaining accuracy in detecting the temperature of the fixing unit.

[0006] The present invention has been made in consideration of the above points, and aims to propose an image forming apparatus that can maintain accuracy in detecting the temperature of the fixing unit while simplifying the configuration of the fixing unit. [Means for solving the problem]

[0007] In order to solve this problem, the image forming apparatus of the present invention comprises a device housing, an image forming unit that transfers a developer image onto a medium, a fixing device that heats the medium onto which the developer image has been transferred and fixes the developer image to the medium, a partition member that is provided between the image forming unit and the fixing device and that forms an internal space, a sensor that is located in the internal space and detects the temperature of the fixing device, a support part that supports the sensor, a measurement hole that connects the internal space to the fixer side in a direction facing the sensor, an intake part that takes in air outside the device housing into the internal space, an exhaust part that exhausts air from the internal space to the outside of the device housing, and a holding member that holds the sensor supported by the support part in the internal space, wherein the holding member is provided with a ventilation path blocking part that is continuously formed from the exhaust part side of the measurement hole to the intake part side, and a measurement hole ventilation space that is provided between the holding member and the support part on the intake part side of the sensor, that connects the internal space to the measurement hole and branches the air taken in by the intake part and directs it towards the measurement hole.

[0008] As a result, the present invention can prevent air from the fixing unit side from being drawn into the sensor side inside the heat insulating member through the measurement hole even when the exhaust unit is operating. [Effects of the Invention]

[0009] According to the present invention, even when the exhaust section is operating, it is possible to prevent air from the fixing unit side from being drawn into the sensor side inside the insulating member through the measurement hole, thereby realizing an image forming apparatus that can maintain the accuracy of detecting the temperature of the fixing unit while simplifying the configuration of the fixing unit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing the external configuration (1) of an image forming apparatus. [Figure 2] FIG. 2 is a plan view showing the external configuration (2) of the image forming apparatus. [Figure 3] FIG. 1 is a right side view showing the internal configuration (1) of an image forming apparatus. [Figure 4] FIG. 2 is a right side view showing the internal configuration (2) of the image forming apparatus. [Figure 5] FIG. 1 is a perspective view showing the internal configuration (3) of the image forming apparatus, where area A is a view of the thermopile unit seen through the rear side plate of the heat insulating duct. [Figure 6] FIG. 2 is a perspective view showing the configuration of a thermopile unit. [Figure 7] FIG. 2 is an exploded perspective view showing the configuration of a thermopile unit. [Figure 8] This is a rear view showing the flow of cooling air (1) with a portion of the rear side plate of the heat insulating duct transparent. [Figure 9] 9 is a cross-sectional view taken along the line AA in FIG. 8, showing the flow (2) of cooling air, and region A is an enlarged view of a part of the engagement portion. [Figure 10] 9 is a cross-sectional view taken along the arrow BB in FIG. 8, showing the flow (3) of cooling air. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

[0012] [1. External configuration of image forming device] 1, 2, and 3, the image forming apparatus 1 has an exterior housing 2 that is a substantially rectangular parallelepiped and formed by resin molding. Here, the direction from the front to the rear of the housing 2 is defined as the rear direction, the direction from the rear to the front of the housing 2 is defined as the front direction, the direction from the bottom to the top of the housing 2 is defined as the up direction, the direction from the top to the bottom of the housing 2 is defined as the down direction, the direction from the right to the left of the housing 2 is defined as the left direction, and the direction from the left to the right of the housing 2 is defined as the right direction.

[0013] The device housing 2 has a device housing front portion 2f on the front side, a device housing top portion 2u on the top side, a device housing rear portion 2b on the rear side, a device housing right side portion 2r on the right side, and a device housing left side portion 2l on the left side.

[0014] The device housing right side 2r has a device housing intake section 4 to the right of a heat insulating duct 30 (described later). The device housing intake section 4 is made up of multiple air vents, connecting the right and left sides of the device housing right side 2r. The device housing left side 2l has a device housing exhaust section 6 to the left of the heat insulating duct 30. The device housing exhaust section 6 is made up of multiple air vents, connecting the right and left sides of the device housing left side 2l. The image forming apparatus 1 takes in air from outside the device housing 2 through the device housing intake section 4 and exhausts air from inside the device housing 2 to the outside through the device housing exhaust section 6.

[0015] [2. Internal structure of image forming device] 3, the image forming apparatus 1 is a monochrome electrophotographic printer that performs monochrome printing and prints a desired monochrome image on paper P, for example, A3 size, A4 size, etc. Inside the apparatus housing 2, various parts are arranged along a transport path R along which the paper P is transported.

[0016] As shown in Fig. 2, main body frames 8r and 8l made of sheet metal and a heat insulating duct 30 are provided inside the device housing 2. The main body frame 8r is a plate-like member extending in the vertical and front-rear directions slightly to the left of the device housing right-side surface 2r inside the device housing 2. The main body frame 8l is a plate-like member extending in the vertical and front-rear directions slightly to the right of the device housing left-side surface 2l inside the device housing 2. Hereinafter, the main body frames 8r and 8l will be collectively referred to as the main body frame 8. The device housing 2 is fixed to this main body frame 8, thereby supporting the device housing 2.

[0017] Heat insulating duct 30 is made of a highly rigid material such as sheet metal, and is disposed between image forming unit 11 and fixing unit 17 in the front-to-rear direction. Heat insulating duct 30 maintains the strength of main body frame 8 by being fixed at its right end to main body frame 8r and its left end to main body frame 8l.

[0018] 3, one image forming unit 11 corresponding to the color of developer (for example, black (K) toner) used in the image forming apparatus 1 is provided on the upper front side between the main body frames 8r and 8l inside the device housing 2. Hereinafter, the left-right direction perpendicular to the transport direction of the paper P and the thickness direction perpendicular to the paper surface of the paper P will also be referred to as the transport width direction.

[0019] The image forming unit 11 forms an electrostatic latent image on the surface of the photosensitive drum 13 by irradiating and exposing the surface of the photosensitive drum 13 with light using the LED head of the head unit 12, and then forms a developer image on the surface of the photosensitive drum 13 by attaching developer supplied from a developer container to the electrostatic latent image.

[0020] A transfer unit 14 is provided below the image forming unit 11 between the main body frames 8r and 8l inside the device housing 2. The transfer unit 14 has a circular transport belt (not shown) that is provided so as to be able to move freely in the front-to-rear direction along the transport path R, and a transfer roller 15 that is disposed below the photosensitive drum 13 and faces the transport belt across it. When the paper P passes between the photosensitive drum 13 and the transport belt, the transfer roller 15 charges the paper P to a polarity opposite to that of the developer, thereby transferring the developer image formed on the photosensitive drum 13 onto the paper P.

[0021] Furthermore, inside the device housing 2, a paper tray 16 for storing paper P is provided below the transfer unit 14 between the main body frame 8r and the main body frame 8l (i.e., at the bottom of the device housing 2). Furthermore, inside the device housing 2, between the main body frame 8r and the main body frame 8l, a pair of conveying rollers for conveying paper P is provided on the conveying path R between the paper tray 16 and the transfer unit 14.

[0022] Furthermore, inside the device housing 2, a fixing unit 17 is provided downstream (i.e., rearward) of the image forming unit 11 in the paper transport direction between the main body frames 8r and 8l. The fixing unit 17 has various components arranged inside a fixing unit housing formed in a substantially box shape. The fixing unit 17 takes in the paper P transported along the transport path R through this paper intake port into the fixing unit housing.

[0023] The fixing unit 17 has a heating roller 18 above the transport path R and a pressure roller 19 disposed below the heating roller 18 and facing the transport path R, and fixes the developer image transferred to the paper P by the transfer unit 14 onto the paper P by applying heat and pressure with the heating roller 18 and pressure roller 19. Furthermore, inside the device housing 2, between the main body frame 8r and the main body frame 8l, on the transport path R between the fixing unit 17 and the paper discharge port 20 (FIG. 3), a pair of discharge rollers and the like are provided, which discharge the paper P from the paper discharge port 20 to a paper stacker section 21 that accumulates the paper P.

[0024] Furthermore, between the main frame 8r and the main frame 8l inside the device housing 2, a heat insulating duct 30 is provided downstream (i.e., rearward) of the image forming unit 11 in the paper transport direction and upstream (i.e., forward) of the fixing unit 17 in the paper transport direction, i.e., between the image forming unit 11 and the fixing unit 17 in the transport direction (front-to-back direction).

[0025] An intake fan 22 (FIG. 2) is fixed to an air vent that is drilled in the main frame 8r at a location facing the device housing intake section 4 of the device housing 2 to communicate between the right and left sides of the main frame 8r. The intake fan 22 takes in air from the outside to the inside of the device housing 2 via the device housing intake section 4 provided in the device housing 2.

[0026] An exhaust fan 23 (FIG. 2) is fixed to a vent hole that is drilled in the main frame 8l at a location facing the device housing exhaust section 6 of the device housing 2 to communicate between the right and left sides of the main frame 8l. The exhaust fan 23 exhausts heat generated by the fixing unit 17, heat that rises as the paper P moves from the fixing unit 17 toward the paper discharge port 20, and heat exhausted from a heat insulating duct exhaust port 34 (described later) to the outside of the device housing 2 via the device housing exhaust section 6 provided in the device housing 2.

[0027] [3. Configuration of insulated duct] 4 and 5, the heat insulation duct 30 has a heat insulation duct front plate 30f on the front side, a heat insulation duct rear plate 30b on the rear side, a heat insulation duct lower plate 30d on the bottom side, and a heat insulation duct upper plate 30u on the top side. The space surrounded by the heat insulation duct front plate 30f, the heat insulation duct rear plate 30b, the heat insulation duct lower plate 30d, and the heat insulation duct upper plate 30u forms the heat insulation duct internal space 32. The heat insulation duct front plate 30f, the heat insulation duct rear plate 30b, and the heat insulation duct upper plate 30u are integrally formed.

[0028] 4 and 5, only the photosensitive drum 13 in the image forming unit 11, the transfer roller 15, the heating roller 18 and pressure roller 19 in the fixing unit 17, the intake fan 22, the exhaust fan 23, the heat insulating duct 30, and the thermopile unit 40 are shown inside the device housing 2, and the rest are omitted.

[0029] The heat insulation duct front plate 30f is a plate-like member that extends with its upper end inclined forward in the up-down and left-right directions as a whole. The heat insulation duct rear plate 30b is a plate-like member that extends with its upper end inclined forward in the up-down and left-right directions as a whole. A circular thermopile hole 35 is provided near the lower end of the heat insulation duct rear plate 30b in the center in the left-right direction. The thermopile hole 35 connects the rear of the heat insulation duct rear plate 30b with the heat insulation duct internal space 32.

[0030] The heat insulation duct upper plate 30u is a plate-like member extending in the front-rear and left-right directions, and connects the upper end of the heat insulation duct front plate 30f to the upper end of the heat insulation duct rear plate 30b. The heat insulation duct lower plate 30d is a plate-like member extending in the front-rear and left-right directions, and connects the lower end of the heat insulation duct front plate 30f to the lower end of the heat insulation duct rear plate 30b.

[0031] An insulated duct air inlet 33, which is an opening surrounded by the insulated duct front plate 30f, the insulated duct rear plate 30b, and the insulated duct upper plate 30u, is formed at the right end of the insulated duct 30. The insulated duct air inlet 33 communicates with the right side of the insulated duct 30 and the insulated duct internal space 32.

[0032] An insulated duct exhaust port 34, which is an opening surrounded by the insulated duct front plate 30f, the insulated duct rear plate 30b, and the insulated duct upper plate 30u, is formed at the left end of the insulated duct 30. The insulated duct exhaust port 34 connects the left side of the insulated duct 30 with the insulated duct internal space 32.

[0033] [4. Thermopile unit configuration] A thermopile unit 40 is provided in the thermally insulated duct internal space 32 of the thermally insulated duct 30. The thermopile unit 40 is disposed below the central axis of the intake fan 22 and the central axis of the exhaust fan 23. As shown in Figures 6 and 7, the thermopile unit 40 is made up of a holding member 42 and a thermopile section 60. The holding member 42 is made up of a holder 44 and a cover 54, and holds the thermopile section 60.

[0034] [4-1. Holder configuration] The holder 44 has a rectangular parallelepiped shape that is thin in the front-rear direction and elongates in the left-right direction, and a duct joint surface 44S that is a flat surface overall is formed on the rear side surface. The thermopile unit 40 is fixed to the thermal insulation duct 30 by screwing it to the thermal insulation duct rear side plate 30b of the thermal insulation duct 30 with the duct joint surface 44S, which serves as the partition member joint surface of the holder 44, abutting against the front side surface 30bS (FIG. 5) of the thermal insulation duct rear side plate 30b.

[0035] A thermopile unit mounting space 45 is formed near the bottom of the center in the left-right direction of the holder 44, and is rectangular when viewed from the rear and recessed forward from the duct joint surface 44S. A substrate fixing portion 46 to which the substrate 64 of the thermopile unit 60 is fixed is formed in front of the thermopile unit mounting space 45, which serves as the sensor mounting space. The holder 44 is formed with a cover opening 47, which is a rectangular opening that exposes the thermopile unit mounting space 45 to the rear. The holder 44 also has a cover abutment surface 48, which is a flat surface facing rearward and surrounds the entire outer periphery of the cover opening 47.

[0036] A left cover surrounding surface 49l is formed from the upper to lower end of the vertically extending surface at the left end of the cover abutment surface 48, which is a flat surface extending rearward to the duct joint surface 44S so as to be perpendicular to the cover abutment surface 48. An upper cover surrounding surface 49u is formed from the upper end of the cover abutment surface 48 from the left to right end of the horizontally extending surface at the left end of the cover abutment surface 48, which is a flat surface extending rearward to the duct joint surface 44S so as to be perpendicular to the cover abutment surface 48. A right cover surrounding surface 49r is formed from approximately the upper half of the vertically extending surface at the right end of the cover abutment surface 48, which is a flat surface extending rearward to the duct joint surface 44S so as to be perpendicular to the cover abutment surface 48. The rear ends of the left cover surrounding surface 49l, the upper cover surrounding surface 49u, and the right cover surrounding surface 49r are perpendicular to the duct joint surface 44S.

[0037] A holder duct portion 51 is recessed downward and to the right of the thermopile portion mounting space 45 in the holder 44, recessed forward from the duct joint surface 44S. Therefore, a holder ventilation space 52 (FIGS. 8 and 9) through which air can pass is formed between the holder 44 and the rear side panel front surface 30bS (FIG. 5). The holder duct portion 51 is formed with a holder duct portion front surface 51Sf and a holder duct portion upper surface 51Su. The holder duct portion front surface 51Sf has a substantially flat shape that slopes forward from left to right, from a location adjacent to a cover duct portion surface 58S (described later) of the cover 54 at the left end to the right side surface of the holder 44 at the right end.

[0038] The holder duct upper side surface 51Su is a flat surface extending from the upper end of the holder duct front side surface 51Sf, from the right end to the left end, rearward to the duct joint surface 44S, perpendicular to the holder duct front side surface 51Sf. The rear end of the holder duct upper side surface 51Su is perpendicular to the duct joint surface 44S. The holder duct upper side surface 51Su as a whole has a substantially planar shape that slopes upward from left to right. In other words, the holder duct upper side surface 51Su can be said to slope upward, toward the intake fan 22, from left to right, in the up-down direction perpendicular to the left-right direction that connects the intake fan 22 and the exhaust fan 23. Therefore, the holder duct 51 is configured so that the cross-sectional area gradually increases from the left end toward the right side surface of the holder 44, which is the right end.

[0039] When the thermopile unit 40 is fixed to the heat insulating duct 30, the holder duct portion 51 communicates the right side of the thermopile unit 40 with the rear side of a cover duct portion surface 58S (described later) of the cover 54.

[0040] Here, the range extending from the lower end of the connection point between the left cover enclosing surface 49l and the duct joint surface 44S upward, through the connection point between the upper cover enclosing surface 49u and the duct joint surface 44S, the connection point between the right cover enclosing surface 49r and the duct joint surface 44S, and the connection point between the holder duct portion upper side surface 51Su and the duct joint surface 44S, to the right side surface of the holder 44, is also referred to as the ventilation path blocking ridge line 50. In this way, in the left-right direction which is the direction connecting the intake fan 22 and the exhaust fan 23, the ventilation path blocking ridge line 50 is continuously formed in the holder 44 from the exhaust fan 23 side (left side) of the lens hole 57A (described later) of the cover 54 to the right end of the duct joint surface 44S which is the intake fan 22 side (right side) of the lens hole 57A of the cover 54.

[0041] When the thermopile unit 40 is attached to the thermal insulation duct 30, the air-passage blocking ridge 50 is tightly attached to the front side surface 30bS of the rear panel without any gaps, thereby preventing air from passing between the thermopile unit 40 and the thermal insulation duct rear panel 30b. In addition, when the thermopile unit 40 is attached to the thermal insulation duct 30, the entire duct joint surface 44S is tightly attached to the front side surface 30bS of the rear panel without any gaps, in addition to the air-passage blocking ridge 50, thereby preventing air from passing between the thermopile unit 40 and the thermal insulation duct rear panel 30b. Furthermore, the left lower end of the duct joint surface 44S is tightly attached to the thermal insulation duct lower panel 30d of the thermal insulation duct 30 without any gaps.

[0042] [4-2. Cover composition] The cover 54 has a rectangular shape as a whole, as viewed from the rear, which is the same shape as the cover opening 47 of the holder 44. A holder abutment surface 55 ( FIG. 9 ), which is a flat surface facing forward and facing the cover opening 47, is formed on the cover 54 so as to surround the entire outer periphery on the front side. Furthermore, a rib 56 ( FIG. 9 ) that protrudes forward beyond the holder abutment surface 55 is formed around the entire periphery on the inner periphery of the holder abutment surface 55 on the front side. The cover 54 is fixed to the holder 44 with screws, with the holder abutment surface 55 abutting against the cover abutment surface 48 of the holder 44. In this state, the rib 56 extends forward of the point of abutment between the cover abutment surface 48 and the holder abutment surface 55 (i.e., toward the thermopile unit mounting space 45).

[0043] The cover 54 (FIGS. 6 and 7) has a lens hole surface 57 formed toward the bottom of the center in the left-right direction. The lens hole surface 57 is a flat surface facing rearward, with its upper end positioned substantially on the same virtual plane as the duct joint surface 44S. A circular lens hole 57A is provided on the lens hole surface 57 at a position facing the thermopile hole 35 (FIG. 5) in the front-rear direction. The lens hole 57A connects the rear of the lens hole surface 57 to the thermopile unit mounting space 45.

[0044] A cover duct portion 58 is formed to the right of the lens hole surface 57. The cover duct portion 58 is connected to the right end of the lens hole surface 57 and has a substantially planar cover duct surface 58S that slopes forward as it extends rightward. Therefore, a cover ventilation space 59 (FIGS. 8 and 9) through which air can pass is formed between the cover 54 and the rear panel front surface 30bS (FIG. 5). The cover duct surface 58S is connected to the holder duct front surface 51Sf of the holder 44 so as to be substantially flush with each other. Therefore, the cover duct portion 58 is adjacent to the holder duct portion 51, allowing air to pass between the holder ventilation space 52 and the cover ventilation space 59. In this way, the cover duct portion 58 communicates the holder ventilation space 52 with the thermopile hole 35 (FIG. 5) when the thermopile unit 40 is fixed to the heat insulating duct 30.

[0045] As described above, the holding member 42 is configured to form the holder ventilation space 52 and the cover ventilation space 59, which connect the intake fan 22 side (right side) of the holder 44 with the thermopile hole 35, on the side of the holder 44 and the cover 54 closer to the intake fan 22 (right side) than the thermopile section 60. Therefore, the holding member 42 allows air to pass from the right side of the holder 44, through the holder ventilation space 52 and the cover ventilation space 59 in this order, past the rear side of the lens hole 57A, and up to the thermopile hole 35.

[0046] [4-3. Thermopile Configuration] The thermopile unit 60 used as a thermopile sensor is constructed by mounting the thermopile 62, which is a non-contact temperature detection sensor, on a substrate 64 that controls the thermopile 62. The thermopile 62 has a thermopile chip and a thermistor used in a temperature compensation circuit or the like sealed inside a metal cylindrical portion. A lens 63, which functions as a filter that transmits infrared light, is provided on the rear surface of the cylindrical portion, facing the image forming unit 11 in the front-to-rear direction. The thermopile unit 60 is fixed so as to be positioned in the thermopile unit mounting space 45 between the holder 44 and the cover 54, by engaging the substrate 64 with a substrate fixing portion 46 formed on the holder 44 and covering the rear surface of the thermopile unit 60 except for the lens 63, with the cover 54.

[0047] [5. Cooling air ventilation path] 6, 8, and 10, a main ventilation passage f1 is formed above the thermopile unit 40 in the heat-insulating duct internal space 32, allowing air to pass from the intake fan 22 to the left toward the exhaust fan 23 through a duct ventilation space 70 serving as a partition member ventilation space, which is the space above the thermopile unit 40. Also, as shown in FIGS. 6, 8, 9, and 10, the holder 44 and the cover 54 form a thermopile ventilation passage f2 that allows air to pass from the intake fan 22 side (right side) of the thermopile unit 40 to the thermopile hole 35, successively passing through the holder ventilation space 52 and the cover ventilation space 59.

[0048] In this configuration, image forming apparatus 1 rotates intake fan 22 and exhaust fan 23 to draw in outside air, which is air outside apparatus housing 2, through apparatus housing intake section 4 (FIG. 2) and take it into apparatus housing 2. At this time, as shown in FIGS. 6, 8, 9, and 10, cooling air Ca, which is air taken in from intake fan 22 and flowed into thermal insulation duct internal space 32 through thermal insulation duct intake port 33, branches into two ventilation paths: main ventilation path f1 that passes above thermopile unit 40, and lower thermopile ventilation path f2 that enters into thermopile unit 40.

[0049] The cooling air Ca flowing along the main ventilation path f1 passes through the duct ventilation space 70 above the thermopile unit 40, reaches the exhaust fan 23 from inside the heat-insulating duct internal space 32 via the heat-insulating duct exhaust port 34, and is then exhausted to the outside of the device housing 2 from the device housing exhaust section 6. Therefore, the cooling air Ca flowing along the main ventilation path f1 exhausts the heated air in the heat-insulating duct internal space 32 to the outside of the device housing 2, ventilating the heat-insulating duct internal space 32. This prevents the heat generated by the fixing unit 17 from being transmitted to the image forming unit 11 in the image forming apparatus 1.

[0050] Meanwhile, the cooling air Ca flowing along the thermopile ventilation path f2 passes through the holder ventilation space 52 and the cover ventilation space 59, passes through the thermopile holes 35, and is discharged to the rear side of the heat-insulating duct rear panel 30b. The holder duct upper surface 51Su slopes upward from the left side (exhaust fan 23) to the right side (intake fan 22). This allows the image forming apparatus 1 to easily direct the cooling air Ca taken in from the intake fan 22 into the holder duct 51 of the thermopile unit 40, which is located below the central axis of the intake fan 22. The cover 54 also has a holder contact surface 55 that is in close contact with the cover contact surface 48 of the holder 44, and a rib 56 that extends forward toward the thermopile mounting space 45. This prevents the cooling air Ca flowing along the thermopile ventilation path f2 from flowing into the thermopile mounting space 45. Furthermore, the cooling air Ca flowing along the thermopile ventilation passage f2 passes behind the lens hole 57A of the cover 54 and is discharged rearward from the thermopile hole 35. Therefore, outside air does not flow into the thermopile unit mounting space 45 via the lens hole 57A of the cover 54.

[0051] In addition, the air passage blocking ridge 50 of the holder 44 is in close contact with the heat insulation duct rear plate 30b without any gaps, so the cooling air Ca behind the cover 54 does not flow into the gap between the holder 44 and the heat insulation duct rear plate 30b.

[0052] [6. Effects, etc.] In the image forming apparatus 1 configured as described above, a heat insulating duct 30 is disposed between the image forming unit 11 and the fixing unit 17 to separate the space between the image forming unit 11 and the fixing unit 17, thereby discharging heat generated by the fixing unit 17 to the outside of the image forming apparatus 1 and preventing it from being transmitted to the image forming unit 11. Furthermore, the image forming apparatus 1 implements a temperature detection sensor that detects the temperature of the heating roller 18 as a thermopile unit 60 in the heat insulating duct 30, which is not a consumable item, rather than in the fixing unit 17, which is a consumable item, thereby simplifying the configuration of the fixing unit 17 and reducing costs. This prevents the temperature detection sensor from having to be replaced along with the fixing unit 17 every time the fixing unit 17, which is a consumable item, is replaced.

[0053] Furthermore, the image forming apparatus 1 is configured so that a thermopile hole 35 is formed in the rear side panel 30b of the thermal insulation duct 30, which faces the fixing unit 17 in the front-to-rear direction, and which allows infrared rays emitted by the fixing unit 17 to pass through and reach the lens 63 of the thermopile 62, which is a non-contact temperature detection sensor.

[0054] Furthermore, in image forming apparatus 1, duct joint surface 44S including ventilation path blocking ridge 50 of holder 44 of thermopile unit 40 is continuously abutted without any gap against rear panel front side surface 30bS from the exhaust fan 23 side (left side) of thermopile hole 35 to the right end of duct joint surface 44S, which is on the intake fan 22 side (right side). This prevents air from flowing leftward from the rear side of cover 54 toward exhaust fan 23 in image forming apparatus 1.

[0055] Therefore, the image forming apparatus 1 can prevent high-temperature, high-humidity air on the fixing unit 17 side from being drawn into the thermopile section 60 side by the exhaust fan 23 through the thermopile hole 35 opened in the heat insulating duct 30.

[0056] In addition, the image forming apparatus 1 is configured to form a holder ventilation space 52 and a cover ventilation space 59, which serve as a thermopile ventilation path f2, connecting the thermopile hole 35 and the intake fan 22 side (right side) of the holder 44, between the front side surface 30bS of the rear panel and the holder 44 and cover 54, on the intake fan 22 side (right side) of the thermopile section 60 in the holder 44 and cover 54.

[0057] Therefore, the image forming apparatus 1 branches the cooling air Ca that is taken in from the intake fan 22 and flows into the insulated duct internal space 32 through the insulated duct intake port 33 into the main ventilation path f1 and the thermopile ventilation path f2, and the cooling air Ca that flows along the thermopile ventilation path f2 can be passed through the holder ventilation space 52 and the cover ventilation space 59, through the thermopile hole 35, and discharged to the rear side of the insulated duct rear side panel 30b.

[0058] In this way, even if the exhaust fan 23 rotates, the image forming apparatus 1 can pass the cooling air Ca taken in from the intake fan 22 through the thermopile ventilation path f2 and discharge it from the thermopile hole 35 without being affected by the exhaust fan 23.

[0059] Therefore, even when the exhaust fan 23 rotates, the image forming apparatus 1 can prevent high-temperature, high-humidity air on the fixing unit 17 side from being drawn into the thermopile section 60 side through the thermopile hole 35 by the exhaust fan 23, thereby preventing condensation on the lens 63 of the thermopile 62. Thus, the image forming apparatus 1 can suppress temperature detection errors of the heating roller 18.

[0060] Furthermore, in the image forming apparatus 1, the holder contact surface 55 of the cover 54 is tightly fitted to the cover contact surface 48 of the holder 44, and the rib 56 is indented forward toward the thermopile unit mounting space 45. This prevents outside air, such as cooling air Ca, from flowing along the thermopile ventilation path f2 into the thermopile unit mounting space 45. This prevents outside air from flowing into the thermopile unit mounting space 45, preventing a temperature difference from occurring between the cylindrical portion of the thermopile 62 and the substrate 64. This improves the accuracy of correction for the thermopile chip and peripheral circuitry using a thermistor sealed inside the cylindrical portion of the thermopile 62. Thus, the image forming apparatus 1 can suppress temperature detection errors of the heating roller 18 caused by temperature differences inside the thermopile unit 60.

[0061] Furthermore, the image forming apparatus 1 can ventilate the inside of the heat-insulating duct internal space 32 by using the cooling air Ca flowing through the main ventilation passage f1, thereby suppressing heat transfer from the fixing unit 17 to the image forming unit 11. As a result, the image forming apparatus 1 can suppress deterioration of print quality due to a rise in temperature of the image forming unit 11.

[0062] According to the above configuration, the image forming apparatus 1 includes the apparatus housing 2, the image forming unit 11 that transfers a developer image onto paper P as a medium, the fixing unit 17 that heats the paper P onto which the developer image has been transferred, and fixes the developer image to the paper P, the heat insulating duct 30 that is provided between the image forming unit 11 and the fixing unit 17 and that has the heat insulating duct internal space 32 as an internal space, the thermopile section 60 that is disposed in the heat insulating duct internal space 32 and detects the temperature of the fixing unit 17, the heat insulating duct rear side panel 30b that supports the thermopile section 60, the thermopile hole 35 that connects the heat insulating duct internal space 32 with the fixing unit 17 side in the direction facing the thermopile section 60, the intake fan 22 that takes in air outside the apparatus housing 2 into the heat insulating duct internal space 32, and the air in the heat insulating duct internal space 32 that is fed into the apparatus housing 2. The heat insulating duct has an exhaust fan (23) that exhausts air to the outside, and a holding member (42) that holds a thermopile section (60) supported by the heat insulating duct rear side plate (30b) in the heat insulating duct internal space (32). The holding member (42) has a ventilation path blocking ridge (50) and a duct joint surface (44S) that serve as ventilation path blocking sections that are continuously formed from the exhaust fan (23) side (left side) to the intake fan (22) side (right side) of the thermopile hole (35). The holding member (42) is provided between the holding member (42) and the heat insulating duct rear side plate (30b) on the intake fan (22) side (right side) of the thermopile section (60), and communicates the heat insulating duct internal space (32) with the thermopile hole (35). The holder ventilation space (52) and the cover ventilation space (59) serve as measurement hole ventilation spaces that branch the cooling air (Ca) that is air taken in by the intake fan (22) and direct it toward the thermopile hole (35).

[0063] This prevents the image forming apparatus 1 from drawing air from the fixing unit 17 side into the thermopile section 60 side inside the heat insulating duct 30 through the thermopile hole 35 even when the exhaust fan 23 is operating.

[0064] 7. Other Embodiments In the above-described embodiment, the image forming apparatus 1 has been described as preventing air from moving leftward from the rear side of the cover 54 toward the exhaust fan 23 by bringing the air-passage blocking ridge 50 of the thermopile unit 40 into tight contact with the thermal insulation duct rear plate 30b of the thermal insulation duct 30 without any gaps, and bringing the entire duct joint surface 44S into tight contact with the thermal insulation duct rear plate 30b of the thermal insulation duct 30 without any gaps, when the thermopile unit 40 is attached to the thermal insulation duct 30. However, the present invention is not limited to this, and the image forming apparatus 1 may also prevent air from moving leftward from the rear side of the cover 54 toward the exhaust fan 23 by bringing any region of the duct joint surface 44S of the thermopile unit 40 into continuous contact with the front side surface 30bS of the rear plate without any gaps, from the exhaust fan 23 side (left side) of the thermopile hole 35 to the intake fan 22 side (right side).

[0065] In the above-described embodiment, the image forming apparatus 1 has been described as having the holder duct upper side surface 51Su inclined upward as it moves from the left to the right as a whole. However, the present invention is not limited to this, and the image forming apparatus 1 may have the holder duct upper side surface 51Su at a constant vertical position as it moves from the left to the right as a whole.

[0066] Furthermore, in the above-described embodiment, the image forming apparatus 1 has been described as forming the holder ventilation space 52 between the holder 44 and the front surface 30bS of the rear panel by recessing the holder duct portion 51 in the holder 44 so as to recess forward from the duct joint surface 44S. However, the present invention is not limited to this. The image forming apparatus 1 may form the holder ventilation space 52 between the holder 44 and the front surface 30bS of the rear panel by recessing a predetermined duct portion in the heat insulating duct rear panel 30b of the heat insulating duct 30 so as to recess backward, rather than forming the holder duct portion 51 in the holder 44. The same applies to the cover ventilation space 59.

[0067] Furthermore, in the above-described embodiment, the image forming apparatus 1 has been described as having the duct joint surface 44S of the holder 44 directly abut against the front side surface 30bS of the rear plate 30b of the heat insulating duct to bring them into close contact with each other. However, the present invention is not limited to this, and the image forming apparatus 1 may have various other members interposed between the duct joint surface 44S and the front side surface 30bS of the rear plate and bring the duct joint surface 44S and the front side surface 30bS into close contact with each other via the members.

[0068] Furthermore, in the above-described embodiment, the image forming apparatus 1 has been described as having the thermopile holes 35 formed in the heat insulating duct rear side plate 30b, which serves as a support portion for supporting the thermopile portion 60. However, the present invention is not limited to this, and the image forming apparatus 1 may have a support portion provided separately from the heat insulating duct rear side plate 30b, and the thermopile holes 35 may be formed in the support portion.

[0069] Furthermore, in the above-described embodiment, the image forming apparatus 1 may be provided with a louver on the lower surface of the insulating duct upper plate 30u of the insulating duct 30, closer to the intake fan 22 (to the right) than the thermopile unit 40, that changes the direction of travel of the cooling air Ca taken in from the intake fan 22 downward toward the thermopile unit 40.

[0070] Furthermore, in the image forming apparatus 1 in the above-described embodiment, the positions of the intake fan 22 and the exhaust fan 23 may be adjusted as appropriate, and the thermopile unit 40 and the heat insulating duct 30 may be inverted upside down.

[0071] Furthermore, in the above-described embodiment, the image forming apparatus 1 has been described as being provided with the thermopile unit 60, which is a non-contact temperature detection sensor, in the heat insulating duct 30. However, the present invention is not limited to this, and the image forming apparatus 1 may be provided with various other non-contact sensors in the heat insulating duct 30.

[0072] Furthermore, in the above-described embodiment, the image forming apparatus 1 has been described as preventing outside air from flowing into the thermopile unit mounting space 45 by bringing the holder abutment surface 55 of the cover 54 into close contact with the cover abutment surface 48 of the holder 44 and by inserting the rib 56 forward toward the thermopile unit mounting space 45. The present invention is not limited to this, and the image forming apparatus 1 may prevent outside air from flowing into the thermopile unit mounting space 45 by providing an elastic body such as a rubber packing between the holder 44 and the cover 54 instead of or together with the rib 56.

[0073] Furthermore, in the above-described embodiment, the present invention has been described as being applied to the image forming apparatus 1, which is a monochrome printer that has one image forming unit 11 corresponding to the color black and performs monochrome printing. However, the present invention is not limited to this, and may be applied to various image forming apparatuses, such as an image forming apparatus that is a color printer that has four image forming units corresponding to the colors yellow, magenta, cyan, and black and performs color printing, or an image forming apparatus that has three or less or five or more image forming units.

[0074] Furthermore, in the above-described embodiment, the present invention has been described as being applied to a printer, but the present invention is not limited to this and may be applied to various devices that perform various image processing, such as a facsimile, an MFP (Multifunction Printer), a copier, etc.

[0075] Furthermore, the present invention is not limited to the above-described embodiment and other embodiments. That is, the scope of application of the present invention extends to embodiments in which the above-described embodiment and the other embodiments are combined in part or in whole. The scope of application of the present invention also extends to embodiments in which part of the configuration described in any of the above-described embodiment and other embodiments is extracted and used as part of the configuration of any of the above-described embodiment and other embodiments, or in which part of the extracted configuration is added to any of the above-described embodiment.

[0076] Furthermore, in the above-described embodiment, the image forming apparatus 1 is configured as an image forming apparatus including the apparatus housing 2 as the apparatus housing, the image forming units 11 as the image forming units, the fixing unit 17 as the fixing device, the heat insulating duct 30 as the partition member, the thermopile section 60 as the sensor, the heat insulating duct rear side panel 30b as the support member, the thermopile hole 35 as the measurement hole, the intake fan 22 as the intake section, the exhaust fan 23 as the exhaust section, and the holding member 42 as the holding member. However, the present invention is not limited to this, and the image forming apparatus may be configured using various other apparatus housings, image forming units, fixing devices, partition members, sensors, support members, measurement holes, intake sections, exhaust sections, and holding members. [Industrial Applicability]

[0077] The present invention can be used not only in a computer that causes a printer to print an image, but also in various electronic devices that perform various image-related processes, such as an image scanner, a facsimile machine, or a copying machine. [Explanation of symbols]

[0078] 1...image forming apparatus, 2...apparatus housing, 2f...front portion of apparatus housing, 2u...top portion of apparatus housing, 2b...rear portion of apparatus housing, 2r...right side portion of apparatus housing, 2l...left side portion of apparatus housing, 4...air intake portion of apparatus housing, 6...exhaust portion of apparatus housing, 8...main body frame, 11...image forming unit, 12...head unit, 13...photosensitive drum, 14...transfer unit, 15...transfer roller, 16...paper tray, 17...fixing unit, 18... ...heating roller, 19...pressure roller, 20...paper discharge port, 21...paper stacker section, 22...intake fan, 23...exhaust fan, 30...insulation duct, 30f...insulation duct front panel, 30b...insulation duct rear panel, 30bS...front side of rear panel, 30d...insulation duct lower panel, 30u...insulation duct upper panel, 32...insulation duct internal space, 33...insulation duct intake port, 34...insulation duct exhaust port, 35...thermopile hole, 40 ……thermopile unit, 42……holding member, 44……holder, 44S……duct joint surface, 45……thermopile unit mounting space, 46……substrate fixing portion, 47……cover opening, 48……cover abutment surface, 49l……left cover enclosure surface, 49u……upper cover enclosure surface, 49r……right cover enclosure surface, 50……ventilation path blocking ridge, 51……holder duct portion, 51Sf……front side surface of holder duct portion, 51Su……upper side surface of holder duct portion, 52 ......Holder ventilation space, 54......Cover, 55......Holder contact surface, 56......Rib, 57......Lens hole surface, 57A......Lens hole, 58......Cover duct portion, 58S......Cover duct surface, 59......Cover ventilation space, 60......Thermopile portion, 62......Thermopile, 63......Lens, 64......Substrate, 70......Duct ventilation space, f1......Main ventilation path, f2......Thermopile ventilation path, P......Paper, R......Transport path, Ca......Cooling air.

Claims

1. A device housing; an image forming unit that transfers a developer image onto a medium; a fixing device that heats the medium onto which the developer image has been transferred, thereby fixing the developer image to the medium; a partition member provided between the image forming unit and the fixing device, the partition member having an internal space; a sensor disposed in the internal space and detecting a temperature of the fixing unit; a support portion that supports the sensor; a measurement hole portion that communicates the internal space with the fixing unit side in a direction facing the sensor; an intake section that takes air outside the device housing into the internal space; an exhaust unit that exhausts air from the internal space to the outside of the device housing; a holding member that holds the sensor supported by the support portion in the internal space; and The holding member is a ventilation path blocking portion formed continuously from the exhaust portion side to the intake portion side relative to the measurement hole portion; a measurement hole ventilation space that is provided between the holding member and the support part on the intake part side of the sensor, that connects the internal space with the measurement hole, and that branches the air taken in by the intake part and directs it toward the measurement hole; An image forming apparatus in which

2. The ventilation path blocking portion blocks air entering the internal space from the measurement hole portion and heading toward the exhaust portion. The image forming apparatus according to claim 1 .

3. The holding member is The air taken into the internal space from the intake section is branched into the measurement hole ventilation space and a partition member ventilation space which is a space outside the holding member and directs the air toward the exhaust section. The image forming apparatus according to claim 1 .

4. the air-passage blocking portion includes a planar partition member joint surface that abuts against a planar portion of the support portion, The measurement hole ventilation space is formed by recessing the partition member joining surface side of the holding member from the partition member joining surface. The image forming apparatus according to claim 1 .

5. The ventilation path blocking portion abuts against the support portion of the partition member without any gap. The image forming apparatus according to claim 1 .

6. The holding member is a sensor mounting space formed between a holder disposed on the image forming unit side and a cover disposed on the fixing device side, the sensor being held in the sensor mounting space; The outer periphery of the cover abuts against the holder without any gap. The image forming apparatus according to claim 1 .

7. The cover has a rib extending from its outer periphery toward the sensor mounting space. The image forming apparatus according to claim 6 .

8. The measurement hole ventilation space is The air intake section extends from the exhaust section side toward the intake section side in a direction perpendicular to a direction connecting the intake section and the exhaust section. The image forming apparatus according to claim 1 .

Images