Image forming device

Abstract

An object of the present invention is to provide an image forming apparatus having an air duct that can efficiently cool necessary areas with a simple configuration. [Solution] The image forming apparatus includes a double-sided conveying path along which paper is conveyed during double-sided printing, an air duct 19 that sends air toward a plurality of air outlets including a double-sided conveying path air outlet 67a facing the double-sided conveying path, an actuator 71 that rotates from a hanging position across the double-sided conveying path to an inclined position when pressed by paper conveyed along the double-sided conveying path, a sensor that detects paper being conveyed on the double-sided conveying path by the rotation of the actuator 71, and a lid 85 that is provided on the actuator 71 and closes the double-sided conveying path air outlet 67a when the actuator 71 rotates to the hanging position and opens the double-sided conveying path air outlet 67a when the actuator 71 rotates to the inclined position.

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus having an air duct for cooling the interior of the apparatus by blowing air. [Background technology]

[0002] An image forming apparatus is equipped with an air duct that sends cooling air to multiple locations that require cooling (e.g., a photosensitive drum, a developing device, a substrate, etc.). The air duct includes a fan that takes in air and generates an airflow, and a duct that directs the airflow generated by the fan to a predetermined location. In recent years, cost reductions have led to a reduction in the number of fans and downgrading, resulting in a decrease in air volume and air speed. Since the number of locations that require cooling remains the same, there is a problem in that a sufficient cooling effect cannot be achieved when the air volume and air speed are limited.

[0003] The image forming apparatus described in Patent Document 1 is equipped with a first ventilation path that blows air from the air blowing means to the image heating device, a second ventilation path that blows air from the air blowing means to the recording material discharged from the image heating device, and a valve that switches the ventilation path from the air blowing means to the first ventilation path and the second ventilation path. By switching the ventilation path from the air blowing means to the object to be cooled (image heating device, recording material, etc.) in this way, it becomes possible to cool multiple objects to be cooled from a single air blowing means. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-231798 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the image forming apparatus has a problem in that the configuration and control for switching the ventilation path by the valve become complicated.

[0006] In consideration of the above circumstances, the present invention aims to provide an image forming apparatus equipped with an air duct that can efficiently cool necessary areas with a simple configuration even when the air volume and air speed are limited. [Means for solving the problem]

[0007] In order to achieve the above object, the image forming apparatus of the present invention is characterized by comprising: a double-sided conveying path along which paper is transported during double-sided printing; an air duct that blows air toward a plurality of air outlets including an air outlet for the double-sided conveying path facing the double-sided conveying path; an actuator that rotates from a hanging position across the double-sided conveying path to an inclined position when pushed by paper transported along the double-sided conveying path; a sensor that detects paper transported along the double-sided conveying path as the actuator rotates; and a lid that is provided on the actuator and closes the air outlet for the double-sided conveying path when the actuator rotates to the hanging position and opens the air outlet for the double-sided conveying path when the actuator rotates to the inclined position.

[0008] In the present invention, the actuator may have a rotating shaft supported along a width direction intersecting the paper transport direction and an actuator piece pressed by the paper, and when the actuator is rotated to the hanging position, the lid hangs down from the rotating shaft due to its own weight, closing the air outlet for the double-sided transport path. [Effects of the Invention]

[0009] According to the present invention, the air outlet is closed while no paper is being transported through the double-sided transport path, so the air blown into the double-sided transport path can be diverted to other areas that require cooling, thereby improving cooling efficiency. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a front view schematically illustrating an internal structure of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional perspective view showing an air duct and an inner frame in the image forming apparatus according to the embodiment of the present invention; FIG. [Figure 3] 1 is a cross-sectional perspective view showing an air duct and an actuator rotated to a hanging position in an image forming apparatus according to an embodiment of the present invention; [Figure 4] 1 is a cross-sectional perspective view showing an air duct and an actuator rotated to an inclined position in an image forming apparatus according to an embodiment of the present invention; [Figure 5] FIG. 2 is a perspective view showing an actuator in the image forming apparatus according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] An image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

[0012] First, the overall configuration of image forming apparatus 1 will be described with reference to Fig. 1. Fig. 1 is a front view schematically showing the internal configuration of image forming apparatus 1. The symbols Fr, Rr, L, and R used in the following drawings represent front, rear, left, and right, respectively.

[0013] The device body 3 of the image forming apparatus 1 is provided with a paper feed cassette 5 that stores paper, a paper feed device 7 that feeds paper from the paper feed cassette 5, an image forming unit 9 that forms a toner image on paper using an electrophotographic method, a fixing device 11 that fixes the toner image on the paper, a discharge device 13 that discharges paper, and a discharge tray 15 on which the discharged paper is stacked. A pair of registration rollers 17 is also disposed between the paper feed device 7 and the image forming unit 9. The device body 3 is also provided with an air duct 19 (not shown in FIG. 1, see FIG. 2) that cools multiple locations.

[0014] The paper feed cassette 5 is housed in a cassette housing section provided at the bottom inside the device main body 3. The paper feed device 7 is located above the front end of the cassette housing section. The registration roller pair 17 is located above the paper feed device 7. The image forming section 9 is located behind the registration roller pair 17. The fixing device 11 is located behind the image forming section 9. The discharge device 13 is located above the fixing device 11. The discharge tray 15 is provided on the top surface of the device main body 3.

[0015] Furthermore, the device main body 3 is formed with a main transport path 21a and a duplex transport path 21b along which paper is transported. The main transport path 21a is formed so as to extend from the paper feed device 7, through the image forming unit 9 and the fixing device 11, toward the discharge device 13. Specifically, the main transport path 21a curves upward toward the rear from the paper feed device 7, passes through the image forming unit 9 and the fixing device 11, and then curves upward toward the discharge device 13. The duplex transport path 21b branches off from the main transport path 21a downstream of the fixing device 11 in the transport direction and merges with the main transport path 21a upstream of the registration roller pair 17 in the transport direction. Specifically, the duplex transport path 21b branches off downward from the main transport path 21a between the fixing device 11 and the discharge device 13, extends forward below the main transport path 21a, and merges with the main transport path 21a between the paper feed device 7 and the registration roller pair 17. The lower conveying surface of the main conveying path 21a and the upper conveying surface of the double-sided conveying path 21b are formed in an inner frame 23. The inner frame 23 will be described later.

[0016] Detection mechanisms 25 for detecting paper are arranged at necessary locations on the main transport path 21a and the double-sided transport path 21b (only the detection mechanism 25 arranged on the double-sided transport path 21b is shown). The detection mechanisms 25 enable a control unit (not shown) to determine whether a paper jam has occurred or when a paper sheet has passed. The detection mechanism 25 arranged on the double-sided transport path 21b will be described later.

[0017] Next, a further description will be given of the image forming section 9. The image forming section 9 is made up of a drum unit 31, a developing unit 33, an exposure device 35, a toner container 37, and a transfer roller 39.

[0018] First, the drum unit 31 will be described. The drum unit 31 includes a photosensitive drum 41, a charging device 43, a cleaning device 45, and a drum housing 47 that supports these. The photosensitive drum 41 is rotatably supported by the drum housing 47. A portion of the outer circumferential surface of the photosensitive drum 41 is exposed through an opening formed in the drum housing 47. The charging device 43 and the cleaning device 45 are disposed around the photosensitive drum 41 along the direction of rotation of the photosensitive drum 41.

[0019] Next, the developing unit 33 will be described. The developing unit 33 includes an agitating roller 51, a supply roller 53, a developing roller 55, and a developing housing 57 that supports these rollers and accommodates the developer. Each roller is rotatably supported in the developing housing 57. A portion of the outer circumferential surface of the developing roller 55 is exposed through an opening formed in the developing housing 57. The portion of the outer circumferential surface of the developing roller 55 exposed through the opening faces, with a predetermined gap therebetween, a portion of the outer circumferential surface of the photosensitive drum 41 exposed through the opening in the drum housing 47 of the drum unit 31.

[0020] Next, the exposure device 35 will be described. The exposure device 35 is disposed above the drum unit 31 and the developing unit 33. The exposure device 35 irradiates the outer peripheral surface of the photosensitive drum 41 with laser light based on image data, thereby forming an electrostatic latent image on the photosensitive drum 41.

[0021] Next, a description will be given of the toner container 37. The toner container 37 is disposed above the developing unit 33. The toner container 37 can communicate with the developing housing 57 of the developing unit 33, and supplies toner to the developing housing 57.

[0022] Next, the transfer roller 39 will be described. The transfer roller 39 is disposed opposite the photosensitive drum 41 exposed from the opening of the drum housing 47 of the drum unit 31, across the main transport path 21a. A transfer nip is formed between the transfer roller 39 and the photosensitive drum 41.

[0023] Next, a brief description of the image forming operation will be given. In the case of single-sided printing, a sheet of paper fed from a paper feed cassette 5 by a paper feed device 7 is transported along a main transport path 21a, and after skew is corrected by a pair of registration rollers 17, the sheet is transported to an image forming unit 9. In the image forming unit 9, a toner image is formed on the sheet of paper. Specifically, in the drum unit 31, a photosensitive drum 41 is charged to a predetermined potential by a charging device 43. Then, an exposure device 35 irradiates the photosensitive drum 41 with a laser beam based on image data, forming an electrostatic latent image on the photosensitive drum 41. In the development unit 33, toner supplied from a toner container 37 is stirred and charged with a developer housed in a development housing 57 by a stirring roller 51. The charged toner is then supplied to a development roller 55 by a supply roller 53 and held on the development roller 55. The held toner is supplied to an electrostatic latent image formed on the photosensitive drum 41, and the electrostatic latent image is developed into a toner image. The toner image is transferred from the photosensitive drum 41 to the paper at the transfer nip. Any toner remaining on the photosensitive drum is removed by a cleaning device 45.

[0024] The paper on which the toner image has been formed is transported along the main transport path 21a to the fixing device 11, where the toner image is fixed to the paper. The paper on which the toner image has been fixed is discharged onto the discharge tray 15 by the discharge device 13.

[0025] During double-sided printing, after a toner image has been fixed on one side of the paper by fixing device 11, the paper passes through fixing device 11, switches back, and is transported to double-sided conveyance path 21b. The paper passes through double-sided conveyance path 21b and is transported along main conveyance path 21a. After the pair of registration rollers 17 corrects the skew of the paper, the toner image is transferred to the other side of the paper in image forming unit 9. The paper with the transferred toner image is transported along main conveyance path 21a to fixing device 11, where the toner image is fixed to the other side of the paper. The paper with the fixed toner image is transported along main conveyance path 21a to discharge device 13, and is discharged by discharge device 13 onto discharge tray 15.

[0026] Next, the inner frame 23 and the air duct 19 will be described with reference to Fig. 2. Fig. 2 is a cross-sectional perspective view showing the inner frame 23 and the air duct 19.

[0027] First, the inner frame 23 will be described. The inner frame 23 has a hollow, approximately rectangular parallelepiped shape that is long in the front-to-rear direction. A plurality of ribs are formed on the upper surface of the inner frame 23 along the conveying direction. Paper sheets conveyed on the main conveying path 21a are conveyed along the upper surface of the inner frame 23 in the conveying direction from front to rear. A plurality of ribs are formed on the lower surface of the inner frame 23 along the conveying direction. Paper sheets conveyed on the double-sided conveying path 21b are conveyed below the lower surface of the inner frame 23 in the conveying direction from rear to front. In this way, the conveying directions on the main conveying path 21a and the double-sided conveying path 21b are opposite. The direction in which paper sheets are conveyed along the double-sided conveying path 21b is referred to as conveying direction X.

[0028] Next, the air duct 19 will be described. The air duct 19 is disposed on the left side of the inner frame 23 and includes a fan 61, a housing 63 that houses the fan 61, a main duct 65 that communicates with the housing 63, and a plurality of branch ducts 67 (see FIGS. 3 and 4) that branch off from the main duct 65 toward a plurality of predetermined locations. The predetermined locations include, for example, the drum unit 31 and the development unit 33 of the image forming unit 9, a control board (not shown), and the double-sided conveying path 21b. The air outlet 67a (see FIGS. 3 and 4) of the branch duct 67 opens toward the predetermined location. The air outlet 67a (air outlet for the double-sided conveying path) of the branch duct 67 disposed toward the double-sided conveying path 21b faces in a direction perpendicular to the conveying direction X.

[0029] When the fan 61 is driven, the air around the housing 63 is drawn into the housing 63. The drawn air passes through the main duct 65 and the multiple branch ducts 67 and is blown out from the air outlet 67a to a predetermined location, thereby cooling the predetermined location.

[0030] Next, the detection mechanism 25 arranged on the double-sided conveying path 21b will be described with reference to Fig. 1 and Fig. 3 to Fig. 5. Fig. 3 and Fig. 4 are perspective views showing the air duct 19 and the detection mechanism 25, and Fig. 5 is a perspective view showing the actuator piece of the detection mechanism 25. As shown in Fig. 1, the detection mechanism 25 includes an actuator 71 and a sensor 73.

[0031] First, a description will be given of the actuator 71. As shown in Figures 3 and 4, the actuator 71 includes a rotary shaft 81, an actuator piece 83 provided on the rotary shaft 81, and a lid 85.

[0032] First, the rotating shaft 81 will be described. The rotating shaft 81 is arranged along the width direction intersecting with the conveying direction X, at approximately the same position in the conveying direction X as the air outlet 67a of the branch duct 67 facing the double-sided conveying path 21b. The rotating shaft 81 crosses the hollow portion of the inner frame 23 and is supported by the inner frame 23 so as to be rotatable but immovable in the width direction.

[0033] Next, the actuator piece 83 will be described. As shown in FIG. 5, the actuator piece 83 is a plate piece that is J-shaped when viewed from the right. The plate thickness direction of the actuator piece 83 is along the width direction. The actuator piece 83 has a light-shielding piece 83a that extends along the front-rear direction and a detection piece 83b that extends downward from the middle of the light-shielding piece 83a. The lower end of the detection piece 83b is curved in an arc shape toward the downstream side in the conveying direction X. The actuator piece 83 is fixed to the center of the rotating shaft 81 and can rotate integrally with the rotating shaft 81. In detail, the vicinity of the intersection of the light-shielding piece 83a and the detection piece 83b is fixed to the rotating shaft 81.

[0034] As shown in FIG. 5, the actuator piece 83 passes through an opening 23a formed in the inner frame 23 and hangs down from the rotation shaft 81 to the double-sided conveying path 21b under its own weight (in a hanging position). In other words, the actuator piece 83 crosses the double-sided conveying path 21b in the vertical direction (see the solid line in FIG. 5). Therefore, when the paper S is conveyed to the double-sided conveying path 21b, the leading edge of the paper S abuts against the lower end of the detection piece 83b of the actuator piece 83. The detection piece 83b is then pushed by the paper S, and the actuator piece 83 rotates so as to be inclined from the rotation shaft 81 toward the downstream side in the conveying direction X (in a tilted position) (see the two-dot chain line in FIG. 5). As the actuator piece 83 rotates, the rotation shaft 81 also rotates clockwise in FIG. 5. On the other hand, when the paper S is conveyed and separates from the actuator piece 83, the actuator piece 83 returns from the inclined position to the hanging position, and the rotation shaft 81 rotates counterclockwise in FIG. 5.

[0035] Next, the lid 85 will be described. As shown in Figures 3 and 4, the lid 85 is a rectangular member having dimensions that allow it to close the air outlet 67a (air outlet for the double-sided conveying path) of the branch duct 67 that faces the double-sided conveying path. The lid 85 is fixed to the left end of the rotation shaft 81 on the right side of the air outlet 67a of the branch duct 67, and is rotatable integrally with the rotation shaft 81.

[0036] As shown in Figure 3, when actuator piece 83 rotates to the hanging position, lid 85 also hangs down from rotating shaft 81 due to its own weight, closing air outlet 67a of branch duct 67. As shown in Figure 4, when actuator piece 83 is pushed by paper transported through duplex conveying path 21b and rotates from the hanging position to an inclined position, lid 85 rotates clockwise together with rotating shaft 81 and moves away from the air outlet. As a result, air outlet 67a is opened. As the paper is transported and moves away from actuator piece 83, actuator piece 83 returns from the inclined position to the hanging position, and rotating shaft 81 rotates counterclockwise, lid 85 rotates counterclockwise together with rotating shaft 81 and closes air outlet 67a again (see Figure 3).

[0037] Next, the sensor 75 will be described. The sensor 75 is an optical sensor having a light-emitting element and a light-receiving element that form an optical path. As shown in FIG. 1, the sensor 75 is disposed in the hollow portion of the inner frame 23. When the actuator piece 83 is rotated to the hanging position, i.e., when no paper is being transported through the duplex conveying path 21b, the light-blocking piece 83a of the actuator piece 83 is separated from the optical path, and the sensor 75 sends an OFF signal to the control unit. When the actuator piece 83 is rotated to the inclined position, i.e., when paper passes through the duplex conveying path 21b, the light-blocking piece 83a blocks the optical path, and the sensor 75 sends an ON signal to the control unit. When the OFF signal is switched to an ON signal, the control unit determines that paper is being transported, and when the ON signal is switched to an OFF signal, it determines that paper has passed.

[0038] In the image forming apparatus 1 having the above configuration, the operation of the actuator 71 when a sheet is transported through the duplex conveying path 21b will be described. During image formation, the fan 61 of the air duct 19 is always driven, blowing air through the main duct 65 and the branch duct 67 to a predetermined location through the air outlet 67a. However, as described above, while no sheet is being transported through the duplex conveying path 21b, the actuator piece 83 of the actuator 71 rotates under its own weight into a hanging position and crosses the duplex conveying path 21b, as shown in FIG. 3. The cover 85 also hangs down from the rotation shaft 81 under its own weight, blocking the air outlet 67a. In other words, no air is blown out through the air outlet 67a. While no sheet is being transported through the duplex conveying path 21b, there is no need to cool the duplex conveying path 21b itself or the sheet, so blocking the air outlet 67a does not cause any problems.

[0039] On the other hand, when paper is transported to duplex conveying path 21b, actuator piece 83 of actuator 71 is pushed by the paper and rotates from a hanging position to an inclined position, as described above, and sensor 75 sends an ON signal to the control unit. The control unit determines that paper is being transported. Furthermore, as shown in FIG. 4, lid 85 rotates clockwise together with rotation shaft 81 and moves away from air outlet 67a, opening air outlet 67a. As a result, air is blown out from air outlet 67a, cooling duplex conveying path 21b and paper transported therethrough. After the paper has passed, actuator piece 83 rotates to a hanging position, and lid 85 rotates counterclockwise together with rotation shaft 81 to close air outlet 67a again.

[0040] As described above, according to the image forming apparatus 1 of the present invention, when no paper is transported through the double-sided transport path 21b, there is no need to cool the double-sided transport path 21b or the paper, so the air outlet 67a is closed. In other words, the air blown out into the double-sided transport path 21b can be diverted to other areas that require cooling. As a result, the amount of airflow increases in other areas, improving cooling efficiency.

[0041] In this way, the limited air volume can be effectively utilized by eliminating the wasteful use of air volume, and therefore there is no need to increase the number of fans 61 or the air volume or speed of the fans 61 in order to improve cooling efficiency.

[0042] In addition, air outlet 67a is opened and closed by cover 85, which is linked to the movement of actuator 71, which is actuated by paper transported through duplex transport path 21b. Therefore, air outlet 67a can be opened and closed with accurate timing. Furthermore, since there is no need to provide a dedicated mechanism for opening and closing air outlet 67a, the number of parts can be reduced.

[0043] Furthermore, when the actuator piece 83 is rotated to the hanging position due to its own weight, the lid 85 also hangs down from the rotation shaft 81 due to its own weight, closing the air outlet 67a. In this way, the lid 85 closes the air outlet 67a in a stable state, so that the air outlet 67a can be closed reliably. Note that a biasing member may be provided to bias the actuator piece 83 to the hanging position. This allows the lid 85 to close the air outlet 67a more reliably.

[0044] Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the above embodiments, and those skilled in the art may modify the above embodiments without departing from the scope and spirit of the present invention. [Explanation of symbols]

[0045] 1. Image forming device 19 Air duct 21b Double-sided transport path 71 Actuator 75 sensors 81 Rotation axis 83 Actuator piece 85 Lid

Claims

1. a duplex transport path through which paper is transported during duplex printing; an air duct that blows air toward a plurality of air outlets including a double-sided conveying path air outlet facing the double-sided conveying path; an actuator that rotates from a hanging position across the double-sided conveying path to an inclined position when pushed by a sheet conveyed along the double-sided conveying path; a sensor that detects the paper being transported through the double-sided transport path by the rotation of the actuator; a cover that is provided on the actuator and closes the air outlet for the double-sided conveying path when the actuator rotates to the hanging position and opens the air outlet for the double-sided conveying path when the actuator rotates to the inclined position.

2. the actuator has a rotation shaft supported along a width direction intersecting a paper transport direction, and an actuator piece that is pressed by the paper; 2. The image forming apparatus according to claim 1, wherein, when the actuator is rotated to the hanging position, the cover hangs down from the rotation shaft due to its own weight, thereby closing the air outlet for the double-sided conveying path.

Images