JP5644801B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of reducing the number of holes formed in a side cover.

  In the image forming apparatus, a circuit board is provided for signal processing and driving of various components such as an electric motor. And in many cases, this circuit board is arrange | positioned in the state which stood the board | substrate upright on either the front, back, left, or right side wall of a housing | casing. Since the circuit board generates a lot of heat when operated, it is necessary to cool the circuit board by creating a flow of air around the circuit board.

  For example, in the image forming apparatus described in Patent Document 1, a substrate placement space is formed on the side wall, an air inlet is provided on the inner wall of the image forming apparatus main body at the lower portion of the substrate placement space, and the substrate placement space is provided. An exhaust port is provided on the side cover side (outer wall) in the upper part of the. Then, an air flow is generated by the fan so that air flows from the space inside the image forming apparatus through the substrate placement space in the side wall from the bottom to the top and exhausts outside through the exhaust port of the side cover.

JP 2011-107511 A

  However, if an exhaust port is provided in the side cover as in the image forming apparatus of Patent Document 1, a metal part such as a clip may enter from the exhaust port, so that there are as few gaps or openings for exhaust or intake as possible. Is desired.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can reduce the number of holes formed in a side cover.

The present invention that solves the problem provides a space between a side frame that holds an image forming unit including a photosensitive member and an exposure device that exposes the photosensitive member, and a side frame that is disposed outside the side frame. An image forming apparatus including a side cover to be formed and at least one circuit board disposed in an arrangement space.
In this image forming apparatus, in at least one of the circuit boards, elements on the circuit board are arranged on the side frame side with respect to the board, and the side frame is moved from the inside of the side frame to the arrangement space. An intake port for intake air and an exhaust port disposed above the intake port for exhausting air from the arrangement space to the inside of the side frame , wherein the side frame has a protrusion that partially protrudes inward. A part of the element on the circuit board enters the bulging portion to the inside of the arrangement space located on the back side of the protrusion, and the side frame has the photoconductor on the inner surface. A guide for guiding the mounting of the process cartridge is formed, and the guide is arranged at a position different from the protrusion .

Thus, by providing the side frame with the intake port and the exhaust port, suctioning from the inside of the side frame, and exhausting to the inside, the number of holes opened in the side cover can be reduced or eliminated. Therefore, it can suppress that a foreign material enters from the hole of a side cover. Further, the appearance of the image forming apparatus can be improved by reducing or eliminating the holes opened in the side cover.
In addition, since the substrate of the circuit board (the raw substrate on which the elements are arranged) is formed of a highly flame-retardant material, when the elements are arranged on the side frame side, that is, inside, the substrate is Since it functions as a flame retardant wall covering the outside of the element, the flame retardance of the side cover disposed on the outside of the substrate can be reduced, and the cost can be reduced.
In addition, according to such a configuration, the bulging portion to the inside of the arrangement space formed by the side frame protruding inward can be used for arrangement of tall elements and is necessary for forming a guide. Since the projections and projections do not have to be provided on the projections, they are provided on the side frames that are located on the relatively outer side, so that the amount of protrusion to the inside of the side frames can be reduced and the image forming apparatus can be made more compact. Can be planned.
Here, the side frame means a frame disposed on any of the front, rear, left and right side walls of the image forming apparatus, and includes not only the left and right walls but also the frames disposed on the front and rear walls. . Similarly, the side cover includes a case where it is a front cover or a rear cover arranged at the front or rear.

  In the above-described apparatus, it is desirable that the air inlet is disposed at a position lower than the element on the circuit board.

  Although air flows from the bottom to the top in the placement space due to the heat generated by the element, according to such a configuration, the air flowing into the placement space from the air inlet can be efficiently used for cooling the circuit board. Can do.

  In the above-described apparatus, it is desirable that the exhaust port is disposed at a higher position than the exposure apparatus.

  According to such a structure, it can suppress that the air which flowed out from the exhaust port heats an exposure apparatus.

  In the above-described apparatus, the exhaust port preferably has a plurality of small holes.

  According to such a configuration, it is possible to prevent the user from inserting a finger or the like from the exhaust port, and it is possible to secure a passage cross section necessary for exhaust at the exhaust port.

  In an apparatus having a circuit board in which the above-described elements are disposed on the side frame side with respect to the board, the circuit board has a height range in the height direction that is higher than the lower end of the intake port and lower than the upper end of the exhaust port. It is desirable that they are arranged overlapping each other.

According to the present invention, it is possible to reduce or eliminate the holes opened in the side cover by providing the side frame with the intake port and the exhaust port, taking in air from the inside of the side frame, and exhausting inward. Therefore, it can suppress that a foreign material enters from the hole of a side cover. Further, the appearance of the image forming apparatus can be improved by reducing or eliminating the holes opened in the side cover.
In addition, according to the present invention, since the circuit board substrate (raw substrate on which the elements are arranged) is formed of a highly flame-retardant material, the elements are arranged on the side frame side, that is, on the inner side. Since the substrate functions as a flame retardant wall that covers the outside of the element, the flame retardance of the side cover arranged outside the substrate can be lowered, and the cost can be reduced.
In addition, according to the present invention, the bulging portion on the inner side of the arrangement space formed by the side frame protruding inward can be used for arrangement of tall elements and the unevenness necessary for forming the guide Since the shape does not need to be provided at the protrusion and is provided at a portion located on the relatively outer side of the side frame, the amount of protrusion to the inside of the side frame is reduced and the image forming apparatus can be made compact. Can do.

1 is a cross-sectional view of an image forming apparatus according to an embodiment. It is the figure which looked at the side frame from the inside. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is the perspective view which looked at the side frame of the state which removed the side cover from the outer side. It is CC sectional drawing of FIG. FIG. 4A is a perspective view and FIG. 4B is a sectional view taken along line DD in FIG.

  Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, first, the overall configuration of a laser printer as an example of an image forming apparatus will be described, and then the features of the present invention will be described in detail.

  In the following description, the direction will be described with reference to the user when using the laser printer. That is, in FIG. 1, the right side toward the paper surface is “front side”, the left side toward the paper surface is “rear side”, the back side toward the paper surface is “right side”, and the front side toward the paper surface is “left side”. To do. In addition, the vertical direction toward the page is defined as the “vertical direction”.

<Schematic configuration of laser printer>
As shown in FIG. 1, the laser printer 1 includes a housing 2 that is an apparatus main body, a feeder unit 3 for feeding paper P, and an image forming unit 4 for forming an image on the paper P. ing.

  The housing 2 mainly includes side walls 200 (shown only on the right side in FIG. 1), a rear cover 21, a top cover 22, an upper wall 25, and a front cover 23 arranged on the left and right. . Details of the structure of the sidewall 200 will be described later. The top cover 22 is configured to be opened and closed up and down with the rear portion as a fulcrum, and a process cartridge 6 (to be described later) can be attached and detached from an opening formed when the top cover 22 is opened.

  The feeder unit 3 is provided with a paper feed tray 31 into which the paper P is placed. Various conveyance mechanisms such as a pickup roller 32 are provided on the rear side of the paper feed tray 31, and the paper P placed on the paper feed tray 31 can be supplied to the image forming unit 4 one by one.

  The image forming unit 4 includes a scanner unit 5 as an example of an exposure device, a process cartridge 6, and a fixing device 7.

The scanner unit 5 is provided on the front side in the housing 2 and includes a laser light emitting unit, a polygon mirror, a lens, a reflecting mirror, and the like (not shown). In the scanner unit 5, a laser beam is irradiated on the surface of a photosensitive drum 61 described later by high-speed scanning. On the scanner unit 5, a partition wall 51 is provided to cover the scanner unit 5. The partition wall 51 has a gap 52 at the front end so that the air in the partition wall 51 can escape to the outside.
Further, the upper wall 25 described above is provided on the partition wall 51, the gap between the upper wall 25 and the partition wall 51, the gap between the upper wall 25 and the front cover 23, and the top cover 22 (discharge tray 9) and the upper wall. It is possible to allow air to escape to the outside through the 25 gaps.

  In addition to the photosensitive drum 61, the process cartridge 6 includes a transfer roller 62 that transfers the toner image on the photosensitive drum 61 onto the paper P, a charger 64, a developing roller 65, a layer thickness regulating blade (not shown), and a toner storage chamber. Etc. The process cartridge 6 can be attached to and detached from the housing 2 through an opening formed when the top cover 22 is opened. Specifically, the shaft 61A of the photosensitive drum 61 is guided by the first guide 212 formed on the side wall 200, and the boss 63 is guided by the second guide 213 so that it can be attached and detached.

  In the process cartridge 6, the surface of the rotating photosensitive drum 61 is uniformly charged by the charger 64 and then exposed by high-speed scanning of the laser beam from the scanner unit 5. As a result, the potential of the exposed portion is lowered, and an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 61.

  Next, the toner in the toner storage chamber is supplied to the electrostatic latent image on the photosensitive drum 61 by the developing roller 65, and a toner image is formed on the surface of the photosensitive drum 61. Thereafter, the paper P is transported between the photosensitive drum 61 and the transfer roller 62, whereby the toner image carried on the surface of the photosensitive drum 61 is transferred onto the paper P.

  The fixing device 7 is disposed above the process cartridge 6 and mainly includes a heating roller 71 and a pressure roller 72.

The heating roller 71 is a member that heats the paper P, and a heat source (not shown) such as a halogen lamp is provided inside the heating roller 71.
The pressure roller 72 is a member that sandwiches and conveys the paper P with the heating roller 71 and is provided obliquely above the heating roller 71.

  In the fixing device 7 configured as described above, the toner transferred onto the paper P is thermally fixed while the paper P passes between the heating roller 71 and the pressure roller 72. The paper P thermally fixed by the fixing device 7 is conveyed to a discharge roller 8 disposed on the downstream side of the fixing device 7, and is discharged from the discharge roller 8 onto a discharge tray 9.

<Configuration of sidewall 200>
As shown in FIGS. 2 and 3, the side wall 200 includes a side frame 210 and a side cover 220. Although a detailed description of the configuration is omitted, the side frame 210 supports the scanner unit 5, the process cartridge 6, and the fixing device 7.

  An arrangement space 290 is formed between the side frame 210 and the side cover 220. In this arrangement space 290, a low-voltage board 230, a high-voltage board 240, and a main board 250 (see FIG. 5) as an example of a circuit board are arranged. Has been.

  The low-voltage board 230 is a circuit board for driving a motor or the like (not shown). As shown in FIG. 5, the low-voltage board 230 is arranged at a position that occupies the lower half of the side frame 210 and projects outward from the side frame 210. The plurality of bosses (not shown) are fixed with screws 239.

The high-voltage board 240 is a circuit board for supplying a voltage to the photosensitive drum 61 and the charger 64 of the process cartridge 6, and is arranged at a position that occupies the upper half of the side frame 210 and outward from the side frame 210. A plurality of bosses (not shown) projecting toward the boss are screwed and fixed with screws 249.

  The main board 250 is a circuit board for performing signal processing of print data input to the laser printer 1, and is arranged corresponding to a range of the side frame 210 protruding upward at the rear part. The lower part of the main substrate 250 overlaps with the upper portion of the substrate 241 of the high-voltage substrate 240 when viewed from the substrate 251.

  As shown in FIG. 3, each element 245 of the low-voltage board 230 is arranged on the side frame 210 side, that is, inside the board 231. Similarly, in the high-voltage board 240, each element 245 is arranged on the side frame 210 side, that is, on the inner side with respect to the board 241. On the other hand, in the main substrate 250, as shown in FIGS. 5 and 6, each element 255 is disposed on the side cover 220 side, that is, outside the substrate 251.

As shown in FIG. 4, a part of the lower side of the side frame 210 partially protrudes inward to form a protruding portion 211, whereby an arrangement space located on the back side of the protruding portion 211. A part of 290 bulges inward to form a bulging portion 290A.
The element 235 provided on the low-voltage substrate 230 has several types of sizes. Among them, the element 235A which is tall and protrudes greatly from the substrate 231 is a bulge corresponding to the back side of the protrusion 211. Part of the portion 290A is slightly inserted.

As shown in FIG. 2, the first guide 212 and the second guide 213 are formed on the inner surface of the side frame 210 as guides for guiding the process cartridge 6 when the process cartridge 6 is mounted on the housing 2. .
The first guide 212 extends downward and rearward from the upper end of the side frame 210, and is formed as a recessed groove when viewed from the inside. The second guide 213 is disposed on the front side of the first guide 212, extends downward and rearward from the upper end of the side frame 210, and is formed as a recessed groove when viewed from the inside. Since the first guide 212 and the second guide 213 are formed at positions different from the protrusion 211 described above, it is not necessary to provide the protrusion 211 with an uneven shape necessary for forming the guide. Therefore, the laser printer 1 can be made compact by reducing the amount of protrusion to the inside of the side frame 210.

  A rectangular intake port 260 that is long in the front-rear direction is formed at the lower end of the front portion of the side frame 210. The air inlet 260 is an opening for introducing cooling air into the arrangement space 290 from the inside of the side frame 210, specifically, from the side of the paper feed tray 31. The air inlet 260 is disposed at a position lower than the elements 235, 245, and 255 on the circuit boards of the low-voltage board 230, the high-voltage board 240, and the main board 250 (see FIG. 3). For this reason, when air flows from the bottom to the top in the arrangement space 290 due to the heat generated by the elements, the air that flows into the arrangement space 290 from the intake port 260 can be efficiently used for cooling each circuit board. it can.

  A substantially trapezoidal first exhaust port 271 is provided in the upper part of the front portion of the side frame 210, and a second exhaust port 272 made up of a plurality of small holes is provided in the upper part near the center in the front-rear direction. The first exhaust port 271 and the second exhaust port 272 are openings that exhaust air from the arrangement space 290 to the inside of the side frame 210. In the laser printer 1 of the present embodiment, cooling air is moved by convection generated by heat generated by each circuit board, and no fan is provided.

As shown in FIG. 1, the first exhaust port 271 is disposed on the scanner unit 5 below the partition wall 51 and opens in a space below the partition wall 51. Thus, the presence of the first exhaust port 271 at a position higher than the scanner unit 5 can suppress the air flowing out from the first exhaust port 271 from heating the scanner unit 5.
Further, since the second exhaust port 272 is also disposed above the scanner unit 5, the air exhausted from the second exhaust port 272 to the inside of the side frame 210 is difficult to heat the scanner unit 5. The second exhaust port 272 is made up of a group of a plurality of small holes, so that the user can not put a finger or the like, and a passage cross section necessary for exhaust can be secured.

  As shown in FIGS. 3 and 4, the low pressure substrate 230 and the high pressure substrate 240 in which the elements 235 and 245 are arranged inside the substrates 231 and 241 are first exhausted above the lower end of the intake port 260 in the height direction. It is arranged so as to overlap the height range below the upper ends of the port 271 and the second exhaust port 272. In other words, the low-pressure substrate 230 that generates a large amount of heat is disposed corresponding to the height of the intake port 260, the first exhaust port 271 and the second exhaust port 272, and is efficiently cooled. Further, a circuit board that generates a large amount of heat, such as the low-pressure board 230, uses the board 231 as a flame-retardant wall by disposing the element 235 inside the board 231. For this reason, the side cover 220 can be manufactured with a raw material with low flame retardance, and cost reduction can be aimed at.

  As shown in FIG. 6, the portion where the main substrate 250 and the high voltage substrate 240 face each other is arranged with the element 255 </ b> A having a short height among the elements 255 in the main substrate 250. A short element 245A of 245 is arranged. In this way, by disposing the low-profile elements 245A and 255A at the portion where the main substrate 250 and the high-voltage substrate 240 face each other, the distance in the facing direction is reduced while the high-voltage substrate 240 and the main substrate 250 are overlapped in the height direction. In addition, the height of the laser printer 1 can be suppressed and the size in the horizontal direction can also be suppressed.

  A hole 218 is formed near the center of the side frame 210 in the height direction, and the voltage supply contact 100 to the charger 64 provided on the high voltage substrate 240 protrudes from the hole 218. The voltage supply contact 100 is in contact with the contact of the charger 64 of the process cartridge 6.

As shown in FIG. 7A, the voltage supply contact 100 has a bullet-shaped contact portion 110 and a flange 120 that extends in the radial direction from the base end of the contact portion 110, and the flange 120 is vertically rectangular. The notch 121 is formed. As shown in FIG. 7B, the voltage supply contact 100 has a flange 120 portion in a guide tube portion 219 formed on the side frame 210. A key 219A extending in the axial direction of the cylinder corresponding to the notch 121 is formed in the guide cylinder 219, and the inside of the guide cylinder 219 can be slid while being engaged with the key 219A. Yes. The voltage supply contact 100 is biased from the outside to the inside by a spring 180, and the tip of the contact portion 110 is pressed against the contact of the charger 64 of the process cartridge 6 by the biasing force of the spring 180. .
Such a voltage supply contact 100 can slide smoothly without being twisted with respect to the guide tube portion 219 by allowing the notch 121 to slide while being engaged with the key 219A, thereby enabling a stable operation.

The operation and effect of the laser printer 1 configured as described above will be described.
When the laser printer 1 is operated, print data is processed by the main substrate 250, a motor (not shown) is driven by the low-pressure substrate 230, and the process cartridge 6 is driven by the high-pressure substrate 240.
By the operation of these circuit boards, heat is generated from the elements 235, 245, and 255, and the temperature in the arrangement space 290 rises due to this heat. When the temperature in the arrangement space 290 rises, a flow of air from the bottom to the top is generated in the arrangement space 290, so that air is introduced into the arrangement space 290 from the inside of the side frame 210 as shown in FIG. Is done. In addition, from the inside of the arrangement space 290, the air heated through the upper first exhaust port 271 is discharged to the inside of the side frame 210, and enters the inside from the first exhaust port 271 as shown in FIG. The air rises in the partition wall 51, passes through the gap 52 at the front end of the partition wall 51, and is discharged to the outside through the gap between the upper wall 25 and the front cover 23.
Further, the heated air in the arrangement space 290 is discharged from the second exhaust port 272 to the inside of the side frame 210 as shown in FIG. As shown in FIG. 1, a part of the air exhausted from the second exhaust port 272 passes under the top cover 22 and the gap between the top cover 22 and the upper wall 25, or the gap between the upper wall 25 and the partition wall 51. And it is discharged to the outside through the gap between the upper wall 25 and the front cover 23. Further, the remainder of the air discharged from the second exhaust port 272 flows to the rear side, rises toward the discharge roller 8, and is discharged to the outside through a gap around the discharge roller 8.

  As described above, according to the laser printer 1 of the present embodiment, the side frame 210 is provided with the intake port 260 and the exhaust port (the first exhaust port 271 and the second exhaust port 272), and sucks air from the inside of the side frame 210. It is exhausted inside. Therefore, the number of holes opened in the side cover 220 can be reduced or eliminated, and foreign matter can be prevented from entering from the holes of the side cover 220. Further, by reducing or eliminating the holes opened in the side cover 220, the appearance design can be improved.

  Note that the heated air that has entered the inside of the side cover 220 is discharged to the outside through a gap in the upper part of the casing 2, but each upper gap has a width (the size in the left-right direction) of the casing 2. ) Can be used for a long time, and even if the size of the gap (distance between walls) is small, the passage section itself using the full width is large, so that sufficient exhaust capacity can be secured. Further, the gap between the top cover 22 and the upper wall 25 and the gap between the upper wall 25 and the partition wall 51 are passages that face each other, so that the passage is longer than the hole that is opened in the side cover 220. be able to. Therefore, air can easily pass through, but since a small piece such as a clip hardly passes through, the problem that a metal piece such as a clip enters the apparatus hardly occurs.

  In the laser printer 1, the elements on the low-voltage substrate 230 and the high-voltage substrate 240 are arranged on the side frame 210 side with respect to the substrates 231 and 241, so that the substrates 231 and 241 serve as flame retardant walls of the elements 235 and 245. It functions, and the flame retardance of the side cover 220 can be lowered to reduce the cost.

  Furthermore, in the laser printer 1 of the present embodiment, a part of the element 235A of the low-pressure board 230 enters the bulging portion 290A of the arrangement space 290 formed on the back side of the protrusion 211, so that the space is effectively used. And can be made compact.

  Further, in the laser printer 1, since the air inlet 260 is disposed at a position lower than the elements 235, 245, and 255, air flowing into the arrangement space 290 from the air inlet 260 is supplied to these elements 235, 245, and 255. It can be efficiently used for cooling.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented.
For example, in the embodiment, three circuit boards are provided, but the number of circuit boards is arbitrary. Further, the number of intake ports or exhaust ports provided in the side frame is also arbitrary.
In the above-described embodiment, a monochrome laser printer is shown as an example of the image forming apparatus. However, the image forming apparatus may be a color printer, a copier, a multifunction peripheral, or the like.
In the embodiment, the image forming apparatus having no fan is exemplified, but a fan may be provided.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Housing | casing 4 Image forming part 5 Scanner unit 6 Process cartridge 21 Rear cover 22 Top cover 23 Front cover 25 Upper wall 51 Bulkhead 52 Gap 61 Photosensitive drum 200 Side wall 210 Side frame 211 Protrusion 212 First guide 213 Second guide 220 Side Cover 230 Low Pressure Substrate 231 Substrate 235, 235A Element 240 High Pressure Substrate 241 Substrate 245, 245A Element 250 Main Substrate 251 Substrate 255, 255A Element 260 Inlet 271 First Exhaust 272 Second Exhaust 290 Arrangement Space 290A Expansion

Claims (5)

A side frame that holds an image forming unit that includes a photoconductor and an exposure device that exposes the photoconductor; a side cover that is disposed outside the side frame and forms an arrangement space between the side frame; An image forming apparatus comprising at least one circuit board arranged in the arrangement space,
At least one of the circuit boards has an element on the circuit board disposed on the side frame side with respect to the board,
The side frame includes an intake port for intake air from the inside of the side frame to the arrangement space, and an exhaust port arranged above the intake port and exhausted from the arrangement space to the inside of the side frame,
The side frame has a protrusion that partially protrudes inward,
A part of the element on the circuit board has entered the bulging portion to the inside of the arrangement space located on the back side of the protrusion,
The side frame has a guide formed on the inner surface for guiding the mounting of the process cartridge having the photosensitive member.
The image forming apparatus , wherein the guide is disposed at a position different from the protrusion . The image forming apparatus according to claim 1, wherein the air inlet is disposed at a position lower than an element on the circuit board. The image forming apparatus according to claim 1, wherein the exhaust port is disposed at a position higher than the exposure apparatus. The image forming apparatus according to claim 1, wherein the exhaust port includes a plurality of small holes. The circuit board in which elements are arranged on the side frame side with respect to the board is arranged so as to overlap a height range above the lower end of the intake port and below the upper end of the exhaust port in the height direction. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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