Image forming device

Abstract

To provide an image forming apparatus that, even if it has a plurality of objects to be cooled and objects to be blown by air, can perform cooling and air blowing with a small number of air blowing devices and in turn can be reduced in size.SOLUTION: An image forming apparatus comprises: an image forming unit that forms a toner image on one surface of a recording material; a fixing unit that fixes the toner image to the one surface of the recording material at a nip part formed by heating means and pressure means; a frame that supports the image forming unit and the fixing unit; an exterior member that covers the frame and includes a through hole; and an electronic circuit board that is arranged between the first frame and the exterior member. The image forming apparatus further has an air blowing device that sucks air from the outside to the inside of the image forming apparatus through the through hole. In an air current generated in the air blowing device, the electronic circuit board is located on the upstream side of the air blowing device, and objects to be blown by air are located on the downstream side of the air blowing device.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an electrophotographic image forming apparatus for forming and fixing an image on a recording material. [Background technology]

[0002] 2. Description of the Related Art In image forming devices such as laser printers, fans are often used as air blowing devices, and most of these are used for cooling purposes.

[0003] Objects that require cooling include electronic circuit boards that convert AC power from an external outlet into the current and voltage used in the image forming device, electronic components that generate heat such as motors, heat generated by friction in the drive units, toner fixers, and paper that has passed through the toner fixers.

[0004] Heat generated by electronic elements and heat generated by friction are essentially unnecessary heat, and if the temperature rises too much, it can have adverse effects such as shortening the life span and reducing efficiency. Although the heat generated by the toner fixing unit is necessary, it is necessary to avoid giving unnecessary heat to surrounding elements.

[0005] As a countermeasure, a method is known in which air is sent to the electronic board using a fan to cool it, and then the air is discharged directly to the outside of the machine (Patent Document 1).

[0006] Similarly, a method is known in which a fan is used to cool the paper that has become hot after fixing (Patent Document 2).

[0007] On the other hand, fans are sometimes used for purposes other than cooling. In the electrophotographic process, there is a phenomenon in which charged products adhere to the photoconductor, causing deterioration of the image. As a countermeasure to this phenomenon, a method is known in which charged products are removed by the wind generated by a fan (Patent Document 3). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2017-44817 A [Patent Document 2] JP 2017-90480 A [Patent Document 3] JP 2013-186322 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, since fans are installed according to their respective purposes, if there are multiple devices inside the image forming apparatus that require airflow, multiple air blowing means must be provided, which increases the space required for the air blowing devices and their air paths, leading to an increase in the size of the image forming apparatus. [Means for solving the problem]

[0010] In order to solve the above problems, an image forming apparatus according to the present invention includes an image forming unit that forms a toner image on a recording material, a fixing unit that fixes the toner image to the recording material at a nip portion formed by a heating means and a pressure means, a frame that supports the image forming unit and the fixing unit, an exterior member that covers the frame and has a through hole, and an electronic circuit board that is arranged between the frame and the exterior member, and further includes an air blower that draws air from the outside of the image forming apparatus to the inside through the through hole, the electronic circuit board is located upstream of the air blower in an air flow generated by the air blower, a blowing target is located downstream of the air blower, and includes a partition member that forms a flow path through which air flows in a vertical direction between the frame and the exterior member, and separates the flow path from a space outside the flow path in a horizontal direction. The electronic circuit board is provided near a bottom surface of the image forming apparatus, and the through hole of the exterior member is provided near the electronic circuit board and on the bottom surface of the image forming apparatus. It is characterized by: Effect of the Invention

[0011] As described above, according to the present invention, even if a configuration has multiple objects to be cooled or blown air, it is possible to provide an image forming apparatus that can cool and blow air with a small number of blowers, thereby enabling the apparatus to be made compact. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view of an image forming apparatus according to a first embodiment of the present invention; [Diagram 2] FIG. 1 is a perspective view of an image forming apparatus according to a first embodiment; [Diagram 3] FIG. 1 is a horizontal cross-sectional view of an image forming apparatus according to a first embodiment. [Figure 4] FIG. 1 is an exploded perspective view showing the inside of an image forming apparatus according to a first embodiment; [Diagram 5] FIG. 1 is a side view showing the inside of an image forming apparatus according to a first embodiment; [Figure 6] FIG. 1 is a partial cross-sectional view showing the inside of an image forming apparatus according to a first embodiment. [Figure 7] FIG. 1 is an exploded perspective view showing a configuration in the vicinity of a paper discharge unit of an image forming apparatus according to a first embodiment; [Figure 8] FIG. 1 is a diagram for explaining an air flow in an image forming apparatus according to a first embodiment. [Figure 9] FIG. 13 is an exploded perspective view of an image forming apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Example 1 A first embodiment of the present invention will be described below.

[0014] (Image forming device) 1 is a schematic diagram illustrating a color laser printer as an example of an image forming apparatus 100. The image forming apparatus 100 has a configuration in which a cartridge door 100a is rotated and opened, and then a cartridge support portion 100b supporting a plurality of cartridges 105 is pulled out from inside the image forming apparatus 100 to the outside, thereby making it possible to replace the cartridges 105. In the following description, the surface of the image forming apparatus 100 on which the cartridge door 100a is provided is referred to as the front surface, the surface opposite the front surface is referred to as the rear surface, and the direction in which the front surface and the rear surface face each other is referred to as the front-rear direction. In addition, when the image forming apparatus 100 is viewed from the direction opposite the front surface, the side surface located to the right is referred to as the right side surface, and the side surface located to the left is referred to as the left side surface.

[0015] The image forming apparatus 100 includes an image forming unit 101, a recording material supply unit 102, and a fixing unit 103. The image forming unit 101 includes a laser scanner 104, a cartridge 105, an intermediate transfer belt 106, and a secondary transfer roller 107. The laser scanner 104 is configured to be able to irradiate the cartridge 105 with laser light.

[0016] Each cartridge 105 includes a toner container 108 that contains toner, a photosensitive drum 109 onto which laser light is irradiated from the laser scanner 104, a charging roller 110 that charges the photosensitive drum 109, and a developing roller 111 that causes the toner to adhere to the photosensitive drum 109. The four cartridges 105 contain yellow, magenta, cyan, and black toner, respectively. The four cartridges 105 are disposed vertically below the laser scanner 104.

[0017] The intermediate transfer belt 106 is disposed vertically below the four cartridges 105. The intermediate transfer belt 106 is an endless belt. A belt drive roller 112, a primary transfer roller 113, and a tension roller 114 are provided on the inner side of the intermediate transfer belt 106 and support the intermediate transfer belt 106. The intermediate transfer belt 106 is rotatable by tension applied by the tension roller 114 and by the transmission of drive from the belt drive roller 112. Four primary transfer rollers 113 are provided and each of them is in contact with the photosensitive drums 109 of the four cartridges 105 with a predetermined pressure, with the belt sandwiched between them. The secondary transfer roller 107 is disposed so as to face the belt drive roller 112 via the intermediate transfer belt 106, and is in contact with the intermediate transfer belt 106 with a predetermined pressure.

[0018] The recording material supplying section 102 is composed of a storage tray 115, a supply roller 116, a separation section 117, and a conveying section 118. The storage tray 115 is a storage section capable of stacking the recording material P, and is configured to be detachable from the image forming apparatus 100 by pulling it forward. The storage tray 115 is provided with a lift plate 119, and is provided so as to be capable of rising and falling according to the number of stacked recording materials P. The supply roller 116 is provided at a position facing the storage tray 115 with the stacked recording materials P sandwiched therebetween. The separation section 117 is located downstream of the supply roller 116, is provided on a conveying guide 120, and is composed of a conveying roller 121 and a separation roller 122. The conveying roller 121 and the separation roller 122 are each provided with a rubber member on their surfaces. The separation roller 122 is provided with a torque limiter built therein, and is configured to generate a predetermined load torque. The separation roller 122 contacts the conveying roller 121 with a predetermined pressure, and when the conveying roller 121 is driven, the conveying roller 121 is driven while generating a predetermined load torque. The conveying section 118 is provided downstream of the separation section 117 and upstream of the nip portion of the secondary transfer roller 107, and is composed of a registration roller pair 123 and a shutter member 124. The shutter member 124 is configured to be rotatable with a predetermined load, and is disposed upstream of the nip portion of the registration roller pair 123. The fixing section 103 is composed of a fixing roller 125, a heat pressing member 126, and a discharge roller pair 127. The fixing roller 125 is disposed downstream of the secondary transfer roller 107, and the heat pressing member 126 contacts the fixing roller 125 with a predetermined pressure. The heat pressing member 126 has a heat generating member 128 inside. The discharge roller pair 127 is provided downstream of the fixing roller 125.

[0019] (Image formation operation) The image forming apparatus 100 starts a printing operation when a print signal is input. The laser scanner 104 irradiates the surfaces of the four photosensitive drums 109 with laser light in accordance with image information to be printed. The photosensitive drums 109 are charged on their surfaces by the charging rollers 110, and an electrostatic latent image is formed in accordance with the irradiated laser light. The electrostatic latent image on the surface of the photosensitive drum 109 is supplied with toner by the developing roller 111, and developed into a toner image. The toner image on the surface of the photosensitive drum 109 is transferred to the intermediate transfer belt 106 by a voltage applied to the primary transfer roller 113. The intermediate transfer belt 106 is driven by the belt drive roller 112 to transport the toner image to a nip portion with the secondary transfer roller 107 while the toner image is transferred from each cartridge 105. In parallel with the above operation, in the recording material supplying section 102, the supply roller 116 transports the recording material P loaded on the storage tray 115 to the separation section 117. When a plurality of sheets of recording material P are conveyed to the separation section 117, only one sheet of recording material P is separated at the nip section by the load torque of the separation roller 122 and conveyed to the conveyance section 118. In the conveyance section 118, the leading edge of the recording material P abuts against the shutter member 124. Since the shutter member 124 is provided with a predetermined rotation load, the recording material P forms a loop by the conveyance force of the separation section 117, pushes aside the shutter member 124, and enters the nip section of the registration roller pair 123. If the recording material P is skewed here, the leading edge of the recording material P that abuts obliquely due to the formation of the loop becomes straight against the shutter member 124, and is held by the registration roller pair 123 to correct the skew. The recording material P that has passed through the registration roller pair 123 is conveyed to the nip section formed between the secondary transfer roller 107 and the belt drive roller 112 while the conveyance speed is controlled, and the toner image conveyed by the intermediate transfer belt 106 is transferred to the recording material P. The recording material P onto which the toner image has been transferred is conveyed to the contact portion between the fixing roller 125 and the heat pressing member 126. The recording material P is pressurized and heated to melt the toner and fix it to the surface. Thereafter, the recording material P is discharged to the outside of the apparatus by a pair of discharge rollers 127, and is sequentially stacked on a discharge tray 129 provided on the top surface of the apparatus.

[0020] (Exterior materials) FIG. 2 is a perspective view of the image forming apparatus 100. An exterior member 130 is disposed on the side (right side) of the image forming apparatus 100. The exterior member 130 is provided with a handle 132, louvers 131 (131a1 to 131a4), and an inlet opening 130a. The handle 132 is formed on the exterior member 130 near the center in the front-rear direction of the image forming apparatus 100 such that a portion connected to the bottom surface of the image forming apparatus 100 is recessed inside the image forming apparatus 100. Although not shown in the figure, a handle is also disposed on the exterior member 130 on the opposite side of the image forming apparatus 100 in the same manner, so that the image forming apparatus 100 can be lifted by hooking fingers on the handle 132 from both sides of the image forming apparatus 100. The position of the handle 132 is disposed in consideration of the center of gravity of the image forming apparatus 100, so that the posture of the apparatus is stable when lifted. The louvers 131 are provided on both sides of the handle 132 in the front-rear direction of the image forming apparatus 100. That is, the exterior member 130 has a plurality of through holes arranged through the louvers 131, and air can be drawn into the inside of the apparatus through the plurality of through holes. The inlet opening 130a allows a power cord to be inserted, and is provided on the rear surface of the exterior member 130 adjacent to and perpendicular to the side surface on which the handle 132 and the louvers 131 are provided. The inlet opening 130a is formed so that an inlet 138 provided in a power supply unit 133 described later is exposed from the inside. The image forming apparatus 100 is supplied with power by connecting a power cord connected to a commercial power source to the inlet 138.

[0021] The internal structure and arrangement of image forming apparatus 100 will be described with reference to Figures 3 to 7. Figure 3 is a horizontal cross section of image forming apparatus 100, and Figure 4 is a right front perspective view with left, right and rear exterior members 130 removed. Figure 5 is a vertical cross section near power supply board 133a taken along dotted line AA in Figure 2, Figure 6 is a vertical cross section near blower device 141 taken along dotted line BB in Figure 2, and Figure 7 is an enlarged view near the paper discharge port with left and right exterior members 130 removed.

[0022] At the center of the image forming apparatus 100, there is provided an image forming unit 136 including an image forming section 101, a recording material supply section 102, a fixing section 103, etc. In the image forming apparatus 100, a main body frame 132 having a right main body frame 132R and a left main body frame 132L is provided so as to sandwich the image forming unit 136 from both sides, and is configured to support the image forming unit 136 (FIG. 3).

[0023] On the outside of the right body frame 132R, a drive unit 134 such as a motor and gears for driving the power supply unit 133 and the rollers of the image forming unit 136 is provided. In other words, the exterior member 130 and the right body frame 132R are arranged to face each other, and the drive unit 134 is attached to the right body frame 132R between them. The exterior member 130R is provided with louvers 131a1 and a4 arranged along two short sides extending along the vertical direction of the power supply board 133a so as to surround the power supply unit 133, and louvers 131a2 and a3 arranged along the lower long side extending along the horizontal direction. This allows outside air to enter and exit the area of ​​the power supply unit 133 from the outside of the image forming apparatus 100 through the through holes provided between the louvers.

[0024] The power supply unit 133 is composed of a power supply board 133a, which is an electronic circuit board, and a board holding member 133b. The power supply board 133a is a low-voltage power supply board and has a substantially rectangular shape. Many electronic elements, including large electronic elements that generate heat, are mounted on the front surface, and low electronic elements are mounted on the back surface. The board holding member 133b is attached to the back surface of the power supply board 133a. The power supply board 133a is fixed to the main body frame 132 via the board holding member 133b so that the short sides of the power supply board 133a are substantially vertical, the long sides of the power supply board 133a are substantially horizontal, and the back surface of the power supply board 133a faces the outside of the image forming apparatus 100.

[0025] The drive unit 134 includes a motor as a drive source, and a drive transmission member (not shown) made of gears or the like, and is capable of transmitting the drive force of the motor to the image forming section 101 .

[0026] On the other hand, a control board 135 that controls the operation is provided on the outside of the left main body frame 132L. That is, the exterior member 136L and the left main body frame 132L are disposed to face each other, and the control board 135 is attached to the left main body frame 132L between them.

[0027] The outside of the main body frame 132 having the right main body frame 132R and the left main body frame 132L in this manner is covered with an exterior member 136. This reduces the leakage of operating noise of the image forming apparatus 100 to the outside of the apparatus, and also suppresses the generation of unintended air flows into the inside of the image forming apparatus 100 from sources other than the louvers 137a1-137a4 and the like provided on the exterior member 136.

[0028] 3 and 6, the image forming apparatus 100 has a partition member 139, which is combined with the exterior member 130R to form a first duct 140 between the right main body frame 132R and the power supply unit 133. In other words, the power supply unit 133 is surrounded by the right main body frame 132R, the partition member 139, the right exterior member 130R, etc., and is separated from the outside of the image forming apparatus 100 and other components inside the image forming apparatus 100.

[0029] The first duct 140 is configured so that one opening is connected to a space formed by the right main body frame 132R, the partition member 139, and the right exterior member 130R that surround the power supply unit 133. The other opening of the first duct 140 is configured so as to be connected to an intake port 141a of a blower device (blower fan) 141 installed vertically above the power supply unit 133 (FIGS. 4 to 7). In this way, the first duct 140 is a sealed air passage that connects the space surrounding the power supply unit 133 to the blower fan 141.

[0030] The blower fan 141 in this embodiment is a type of centrifugal fan. The blower fan 141 is installed so that the rotor blades are approximately horizontal, and the air inlet 141a faces the first duct 140, that is, vertically downward. More specifically, the blower fan 141 and the power supply board 133a are arranged so that an image of the blower fan 141 projected from the vertical direction onto a horizontal plane overlaps with an image of the power supply board 133a projected from the vertical direction onto a horizontal plane. As shown in FIG. 7, the exhaust port 141b of the blower fan 141 is connected to a cooling outlet 143 that blows air onto the image forming surface of the paper P just before the paper P passes through the pair of discharge rollers 127 and is placed on the discharge tray 129. In this embodiment, the second duct 142 is configured to form a closed air passage, one end of which is connected to the exhaust port 141b of the blower fan 141 and the other end of which is the cooling outlet 143.

[0031] (Cooling inside the image forming apparatus 100) In image forming apparatus 100, power supply board 133a has the function of converting commercial power into a predetermined voltage and current in order to operate image forming apparatus 100. It is a heat source that generates heat during the conversion and therefore needs to be cooled.

[0032] On the other hand, since the toner image is heated and fixed to the paper P in the fixing unit 103, the paper P is hot immediately after the image is fixed, and depending on the type of paper and the image, it may be discharged and stacked on the discharge tray 129 before the fixed toner cools and hardens, causing the sheets of paper P to stick together with the toner. To prevent this, the paper needs to be cooled by blowing air immediately after being discharged.

[0033] Therefore, in this embodiment, the power supply board 133a is cooled by the airflow generated upstream of the blower fan 141, and the paper P immediately after the image is fixed is cooled by the airflow generated downstream of the blower fan 141. The cooling operation for cooling the power supply board 133a and the paper P immediately after the image is fixed will be described in detail below.

[0034] When the image forming apparatus 100 is turned on and the blower fan 141 is driven, the intake side corresponding to the upstream side of the intake port 141a becomes negative pressure. As a result, outside air flows into the vicinity of the power supply unit 133 as indicated by the arrow a in the figure from the louvers 131a provided on the exterior member 130 around the power supply unit 133 through the first duct 140 connected to the intake port 141a (FIG. 6). This outside air flows along the front side of the power supply board 133a as indicated by the arrow b, and the electronic elements on the power supply board 133a, which is the first heat source element, are cooled. At this time, as shown in FIG. 5, the louvers 131a1 to 131a4 are arranged near three sides of the power supply board 133a except for the upper long side, and the first duct 140 is installed near the upper long side. Therefore, the length of each air flow (arrows b1, b2, b3, b4) sucked through each louver 131a1 to 131a4 becomes shorter on average, making it possible to efficiently cool the entire power supply board 133a with the flowing air.

[0035] If there is a bias in the temperature rise of the electronic elements on the power supply board 133a, it is preferable to reduce the opening area of ​​the louvers corresponding to the parts with a small temperature rise and increase the opening area of ​​the louvers corresponding to the parts with a large temperature rise. This allows the amount of outside air introduced through each louver to be adjusted to achieve a cooling balance.

[0036] Then, the air that has cooled the power supply board 133a passes through the first duct 140 as shown by the arrow c in FIG. 5 and FIG. 5, and is sucked into the blower fan 141. The sucked air is accelerated by the blower fan 141, and is sent to the second duct 142 connected to the exhaust side that corresponds to the downstream side of the exhaust port 141b. One end of the second duct 142 is connected to the exhaust port 141b of the blower fan 141, and the other end is a cooling outlet 143, and the air is exhausted to the outside of the image forming apparatus 100. At this time, the air exhausted from the cooling outlet 143 is blown, as shown by the arrow d, against the image forming surface of the paper P that has just been fixed and is hot and has been discharged from the discharge roller pair 127, outside the image forming apparatus 100, to cool the paper P.

[0037] The air blown onto the paper P from the cooling outlet 143 of the second duct 142 is air that has cooled the power supply board 133, and therefore has a higher temperature than the outside air. However, since this temperature is sufficiently lower than the temperature of the paper P immediately after it is heated by the fixing unit 103 and the re-solidification temperature of the toner melted in the fixing unit 103, it is possible to cool the paper P and prevent the papers P stacked on the discharge tray 129 from sticking to each other.

[0038] As described above, by arranging cooling targets on the intake side, which corresponds to the upstream side of the blower fan 141, and the exhaust side, which corresponds to the downstream side, it becomes possible to efficiently cool multiple cooling targets with one fan. This makes it possible to save space and costs without having to install fans for each of the multiple cooling targets, or to install larger and more powerful fans and ducts to branch the airflow. In addition, since only one fan is required, it is possible to reduce noise generated by the fan. In addition, by arranging cooling targets in front of and behind the fan, it is possible to ensure a distance from the intake section (multiple through holes arranged through the louver 131) provided in the exterior member 130 of the image forming apparatus to the fan, which is a noise source. This reduces leakage of operating noise to the outside of the apparatus, and also makes it possible to reduce the noise of the image forming apparatus.

[0039] Example 2 In the first embodiment, one cooling target is disposed on each of the upstream and downstream sides of the blower, but it is not necessary to dispose one cooling target on each side. Furthermore, the blower may be configured so that the wind flows not only near the cooling target, but also near the blower for other purposes.

[0040] Here, the other uses include, for example, ventilation. In the electrophotographic process, the photoconductor drum 109 is charged to form an electrophotographic image. At this time, ozone is generated by corona discharge, and charged products such as nitrogen oxides (NOx) are generated inside the image forming apparatus 100, which may adhere to the photoconductor drum 109. When the charged products adhere to the photoconductor drum 109, moisture is likely to adhere thereto. As a result, the moisture on the photoconductor drum 109 causes the charged charges on the surface of the photoconductor drum to flow, resulting in image defects.

[0041] Therefore, in this embodiment, similarly to the first embodiment, not only is a cooling target disposed on the upstream and downstream sides of the blower, but also a photoconductor drum 109 is disposed downstream of the blower as another target, thereby preventing adhesion of charged products and suppressing the occurrence of image defects. The configuration of this embodiment will be described in detail below.

[0042] The second embodiment will be described with reference to Figs. 8 and 9. Fig. 8 is a top view of the second embodiment with the top exterior member and the laser scanner removed, and Fig. 9 is an enlarged view of the third duct and its vicinity added in the second embodiment. The image forming apparatus 100 of the second embodiment is provided with a power supply unit 133 as in the first embodiment, and a first duct 140 and a blower fan 141 are provided vertically above the power supply unit 133. A second duct 142 different from that of the first embodiment is connected to an exhaust port 141b of the blower fan 141. The second duct has a branch port 144 in addition to a cooling outlet 143, unlike the first embodiment. A third duct 145 is connected to the branch port 144.

[0043] One end of the third duct 145 is connected to the branch port 144, and the other end is branched into four ventilation outlets 146. Each of the ventilation outlets 146 is directed toward the photosensitive drum 109 of the cartridge 105 of each of the four colors, and air is blown toward the photosensitive drum 109 as indicated by the arrow e.

[0044] A hole (not shown) is formed in the left main body frame 132L near the photosensitive drum 109, and further, a left exterior member 130L on the outside of the left main body frame 132 is provided with a louver (not shown).

[0045] (Cooling inside the image forming apparatus 100) The power supply board 133, the blower fan 141 for cooling the paper P after fixing, the first duct 140, and the second duct 142 have the same configurations and effects as those of the first embodiment.

[0046] When image forming apparatus 100 is turned on and blower fan 141 is driven, the intake side corresponding to the upstream side of intake port 141a becomes negative pressure. As a result, outside air flows into the vicinity of power supply unit 133 as shown by arrow a in the figure through first duct 140 connected to intake port 141a and via louvers 131a provided on exterior member 130 around power supply unit 133 (FIG. 6). This outside air flows along the front side of power supply board 133a as shown by arrow b, and the electronic elements on power supply board 133a, which is the first heat source element, are cooled.

[0047] The air that has cooled the power supply board 133a passes through the first duct 140 as indicated by the arrow c in FIG. 5 and is sucked into the blower fan 141. The sucked air is accelerated by the blower fan 141 and sent to the second duct 142 connected to the exhaust side downstream of the exhaust port 141b. One end of the second duct 142 is connected to the exhaust port 141b of the blower fan 141, and the other end is a cooling outlet 143, through which the air is exhausted to the outside of the image forming apparatus 100. At this time, the air exhausted from the cooling outlet 143 is blown, as indicated by the arrow d, onto the image forming surface of the paper P that has just been fixed and is hot and has been discharged from the discharge roller pair 127 outside the image forming apparatus 100, thereby cooling the paper P.

[0048] Meanwhile, in this embodiment, the second duct has a branch outlet 144 in addition to the cooling outlet 143, and the air sucked in by the blower fan 141 is sent to a third duct 145 connected to the branch outlet 144. One end of the third duct 145 is connected to the branch outlet 144, and the other end forms four ventilation outlets 146, which are respectively blown onto the photosensitive drums 109 of the cartridges 105 of four colors. This prevents the adhesion of charged products to the photosensitive drums 109, and makes it possible to provide an image forming apparatus 100 that suppresses the occurrence of image defects.

[0049] In addition, since the purpose of the third duct's airflow is ventilation, the warm air after cooling the power supply board can also be used to prevent image defects without any problems.

[0050] The air blown onto the photosensitive drum 109 passes between the exterior member 136L and the left main body frame 132L through a hole provided in the left main body frame 132L, and can be discharged to the outside of the image forming apparatus 100 through a through hole between the louvers provided in the left exterior member 130L.

[0051] As described above, cooling targets are arranged on the intake side, which is the upstream side of the blower fan 141, and on the exhaust side, which is the downstream side, of the blower fan 141, and further, the blowing target is arranged on the exhaust side, which is the downstream side of the blower fan 141. This makes it possible to efficiently utilize the air flow that can be generated by one fan. In other words, it is possible to save space and costs without installing fans for multiple cooling targets or blowing targets, or installing larger and more powerful fans for each of the cooling targets or blowing targets. In addition, since only one fan is required, the noise generated by the fan can be reduced. In addition, by installing the cooling targets or blowing targets in front of and behind the fan, it is possible to ensure a distance from the louver that covers the opening of the image forming apparatus to the fan, which is a noise source, and it is possible to reduce the leakage of operating noise to the outside of the apparatus and reduce the noise of the image forming apparatus.

[0052] (Modification) In the first and second embodiments, the blower fan is a type of centrifugal fan, but the blower does not necessarily have to be a blower fan, and may be an axial fan, a rotary fan, etc. Also, a blower other than a fan, such as a fan or a bellows, may be used.

[0053] Axial fans can generally be introduced at a lower cost than blower fans, but because they have lower static pressure than blower fans, it is necessary to reduce pressure loss in the air duct, in other words, to make the air duct wide and short.

[0054] Bellows blow discontinuous air, so when used to cool paper output, adjustments such as timing are required. However, because it is possible to obtain high static pressure, it is possible to blow air even through long or narrow air ducts, which increases the freedom of installation. [Explanation of symbols]

[0055] 100 Image forming device 101 Image forming section 102 Recording material supply unit 103 Fixing unit 105 Cartridge 106 Intermediate transfer belt 107 Secondary transfer roller 109 Photoconductor drum 127 Discharge Roller Pair 129 Output Tray 130 Exterior materials 131 Louver 132 Main frame 133 Power supply unit 136 Image forming unit 137 Air Duct 141 Blower fan 140 First Duct 142 Second Duct 143 Cooling outlet 144 Branch Exit 145 3rd Duct 146 Ventilation outlet P Recording material

Claims

1. an image forming unit that forms a toner image on a recording material; a fixing section for fixing the toner image onto the recording material at a nip section formed by a heating section and a pressure section; a frame supporting the image forming unit and the fixing unit; An exterior member having a through hole that covers the frame; an electronic circuit board disposed between the frame and the exterior member; In an image forming apparatus comprising: a blower that draws air from the outside of the image forming apparatus to the inside of the image forming apparatus through the through hole, the electronic circuit board is located upstream of the air blower in the airflow generated by the air blower, and a blowing target is located downstream of the air blower; a partition member that forms a flow path through which air flows in a vertical direction between the frame and the exterior member, the partition member separating the flow path from a space outside the flow path in a horizontal direction; the electronic circuit board is provided near a bottom surface of the image forming apparatus, The through hole of the exterior member is provided on a bottom surface of the image forming apparatus near the electronic circuit board.

1. An image forming apparatus comprising:

2. The blower and the electronic circuit board are arranged so that an image of the blower projected from a vertical direction onto a horizontal plane and an image of the electronic circuit board projected from a vertical direction onto the horizontal plane overlap with each other.

2. The image forming apparatus according to claim 1,

3. The target of the air blowing is a recording material on which the toner image has been fixed in the fixing unit.

3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

4. The target of the air blowing is a photosensitive drum of the image forming unit.

3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

5. 4. The image forming apparatus according to claim 1, wherein the target of air blowing is a plurality of targets.

6. The electronic circuit board is a low-voltage power supply board.

6. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

7. The blower is any one of a centrifugal fan, an axial fan, a rotary fan, a fan, and a bellows.

6. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

8. The blower is a centrifugal fan.

2. The image forming apparatus according to claim 1,

9. The through-holes of the exterior member are provided on the bottom surface of the image forming apparatus and on two surfaces perpendicular to the bottom surface.

2. The image forming apparatus according to claim 1,

Images