JPH07299929A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To prevent the temp. rise of an electric element substrate and to reduce the occupying area of an apparatus main body. CONSTITUTION:A laterally protruding stepped part 6a is provided to the lower part of an apparatus main body 1 and an exhaust hole 6b is provided to the upper surface thereof. The part severe in the generation of heat on a substrate 80 is arranged just below the exhaust hole 6b to prevent a temp. rise. The stepped part 6a is not provided to the whole in the left and right direction of the apparatus main body 1 and notch parts 6L, 6R are provided to the left and right end parts thereof. By connecting a power supply connector 80d and an interface connector 80b, the occupying area of the apparatus main body 1 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image on a recording medium.

[0002]

2. Description of the Related Art In electrophotographic image forming apparatuses such as copiers and laser beam printers used in offices, etc., in particular, small desktop type apparatuses, further miniaturization is required.

FIG. 7 shows a conventional laser beam printer. This is a paper feed tray 110 on which recording media P before image formation are stacked, and a paper ejection tray 1 formed on the top of the apparatus main body 101 and ejecting recording media P after image formation.
20 and a recording medium P that connects both trays 110 and 120
And the transport path 130. A process cartridge 140 having a photosensitive drum 141 is arranged in the transport path 130. The photosensitive drum 141 is uniformly charged by the charging roller 142, and an electrostatic latent image corresponding to image information is formed by the light irradiation unit 150, the reflection mirror 154 and the like. Toner is attached to the electrostatic latent image by the developing roller 143 and is developed as a toner image. The toner image on the photosensitive drum 141 is transferred by the transfer roller 160 onto the surface of the recording medium P supplied from the paper feed tray 110 via the paper feed roller 135 and the transport roller 136. The toner image on the surface of the recording medium P after the transfer of the toner image is fixed by the fixing device 170, and then the conveyance roller 137,
The sheet is discharged onto the sheet discharge tray 120 via the discharge roller 138. On the other hand, the photosensitive drum 141 after the toner image transfer is
The residual toner on the surface is removed by the cleaning blade 144 and is used for the next image formation.

A printed circuit board 180 integrally provided with circuits such as a power source, a high voltage circuit, and a CPU is disposed below the above-mentioned transport path 130, that is, below the apparatus main body 101.

With the above structure, the transport path 130
Also, since each process means can be arranged close to the printed circuit board 180, connection for supplying a voltage to each process means is easy, and the transport path 130 is also provided.
Detecting means for detecting the recording medium P therein and the printed circuit board 18
It is easy to connect to the components on the top.

Therefore, it is possible to construct a compact image forming apparatus which is easy to assemble and has a small number of parts.

[0007]

However, according to the above-mentioned image forming apparatus, since the functional components of each process means are arranged above the printed circuit board 180, when the temperature of the electrical components on the printed circuit board 180 rises. In addition, there is a problem in that the heated air is difficult to be discharged to the outside of the apparatus main body 10 and the temperature of the electric components on the printed circuit board 180 easily rises. Therefore, it is necessary to take heat countermeasures such as providing an exhaust fan having a large flow rate in the vicinity.

Further, as shown in the plan view of FIG. 8, it is common to connect a power supply connector 181 and an interface connector 182 to the rear part of the apparatus main body (left side in the same figure).
Since the occupied area of the apparatus main body 101 including the space is determined, there is a problem that the occupied area tends to be large. Further, as shown in FIG. 8, the recording medium P before and after the image formation is supported substantially horizontally by the paper feed tray 110 and the paper discharge tray 120, respectively. It is difficult to make it smaller than the area, and there is a problem that there is a limit to the reduction of the occupied area.

Therefore, it is an object of the present invention to provide an image forming apparatus in which the temperature rise of electric parts on a printed circuit board is suppressed and the area occupied by the apparatus main body is reduced.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the structure of the present invention is an image forming apparatus for forming an image on a recording medium, in which a recording medium for feeding is supported in a vertical direction. 1 support means, a second support means for supporting the recording medium after image formation in the longitudinal direction, an image carrier provided above a transport path from the first support means to the second support means, Between the first support means and the second support means,
Information light emitting means provided above the image carrier for giving information light according to image information to the image carrier,
A transfer unit provided below the transport path for transferring the toner image formed on the image carrier to a recording medium;
A fixing unit for fixing the toner image transferred to the recording medium to the recording medium, an electric board having a heat generating member on the upper surface and arranged below the conveying path, and a lateral projection at the lower part of the apparatus main body. And a step portion having a vent hole on the upper surface thereof, and the electric component board is arranged such that the heat generating member of the electric component board is located at the step portion.

In this case, the stepped portion may be provided with a cutout portion for connecting the inlet portion or a cutout portion for connecting the interface connector.

A feeding position for feeding the recording medium supported by the first supporting means and a transfer position by the transferring means, which are arranged in order from the upstream side to the downstream side of the conveying path,
The fixing position by the fixing unit can be sequentially arranged at a lower position in this order.

Further, the fixing means has a heating portion, rises along the back surface of the second supporting means for discharging heat from the heating portion, and has an outlet at the upper part of the image forming apparatus main body. Two exhaust heat ducts are provided, or the second exhaust heat duct is
A partition wall may be provided above the transport path to thermally block heat from the fixing unit from reaching the image carrier.

Further, the second supporting means also serves as an outer cover that can be opened and closed with respect to the image forming apparatus main body, or the second supporting means can be an outer cover that can be opened and closed with respect to the image forming apparatus main body. Also, the second exhaust heat duct may be provided integrally with the exterior cover.

The electrical board includes a controller, a high voltage generator and an A
A recording medium having a C input section, the control section being arranged on the downstream side, and the high voltage generating section and the AC input section being arranged on the upstream side, and being supported by the first supporting means. It is also possible to dispose a motor below a feeding position for feeding the above, and to provide a first exhaust heat duct along the back surface of the first supporting means above the motor.

Next, the information light emitting means may emit a laser beam.

The information light emitting means comprises a semiconductor laser,
A polygon mirror, a lens, and a reflection mirror, wherein the polygon mirror is arranged on the side of the first supporting means, the reflection mirror is arranged on the side of the second supporting means, and the polygon mirror is arranged downward. The reflecting mirror can be arranged above.

The information light emitting means may have an LED array arranged so as to face the image carrier.

Next, in the image carrier, the electrophotographic photosensitive member as the image carrier and at least one of the charging means, the developing means, and the cleaning means are integrally made into a cartridge to form a main body in the image forming apparatus. In contrast, the image carrier is provided in a detachable process cartridge, or the image carrier integrally includes an electrophotographic photosensitive member as the image carrier and a charging unit, a developing unit, or a cleaning unit. Provided in a process cartridge which is made detachable with respect to the main body of the image forming apparatus, or the image carrier is a cartridge in which at least a developing unit and an electrophotographic photosensitive member as the image carrier are integrally formed. It may be provided in a process cartridge that is detachable from the main body of the image forming apparatus.

[0020]

According to the above structure, the temperature rise can be suppressed by arranging the heat generating member of the electrical equipment substrate in the step portion which projects from the apparatus main body and has the ventilation hole on the upper surface.

The recording medium before and after the image formation is vertically supported by the first supporting means and the second supporting means, respectively, and the notch for connecting the inlet portion of the power source or the interface connector is provided as the stepped portion. The area occupied by the main body of the apparatus can be reduced by providing the above.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 shows a schematic configuration of a laser beam printer M using a process cartridge as an example of an image forming apparatus according to the present invention. In each of the figures including this figure, the left side is the "front" of the printer body 1 and the right side is the "rear". According to this, regarding the upstream and the downstream of the recording medium P in the transport direction, the rear part is the upstream side and the front part is the downstream side. The recording medium P on which an image is to be formed is not only ordinary plain paper (copy paper), but also special paper such as thick paper and envelopes, and other than paper such as O.
Sheet material such as HP film can be used,
In this embodiment, the case of using ordinary plain paper will be described.

First, an outline of the configuration of a laser beam printer (hereinafter simply referred to as "printer") M shown in the figure will be described.

The printer M is referred to as a printer main body 1 (hereinafter simply referred to as "main body 1". In the following description,
The term "main body" refers to not only the frame forming the exterior of the printer M but also the frame forming the inside. ) A first supporting means 10 for supporting the recording medium P before image formation in the vertical direction is provided at the rear part, and a second supporting means 10 for supporting the recording medium P after image formation in the vertical direction is provided at the front part of the main body 1. Support means 20 is provided. Then, the lower end portion 10 a of the first supporting means 10 and the lower end portion 2 of the second supporting means 20.
0a and the conveyance path 3 extending from the rear part of the main body 1 to the front part
Connected with 0, and as a whole, a U-shaped path (hereinafter, “vertical U
Character path ". ) Is composed. The printer M also includes a process cartridge 40 in which a drum-shaped electrophotographic photosensitive member (hereinafter, referred to as “photosensitive drum”) 41 arranged immediately above the transport path 30 is integrally incorporated, and the process cartridge 40. The information light emitting means 50 arranged above, the transfer means 60 arranged below the intermediate portion of the conveying path 30 so as to face the photosensitive drum 41, and the second means on the downstream side of the conveying path 30.
Fixing means 70 arranged just below the lower end of the supporting means 20
It has and. Based on the above-mentioned vertical U-shaped path, the process cartridge 40 and the information light emitting means 50 are arranged inside thereof, the transfer means 60 is arranged outside thereof, and the fixing means 70 is arranged so as to straddle the conveyance path 30 on the downstream side. Will be arranged respectively.

The operation of the printer M having the above structure will be briefly described. First, a toner image is formed on the photosensitive drum 41 by the information light emitting means 50 and the like. On the other hand, the recording medium P is fed downward from the first supporting means 10 to convey the recording path 30.
Is supplied to the photosensitive drum 41 via the upstream side of the above, and the above-mentioned toner image on the photosensitive drum 41 is transferred to the supplied recording medium P by the transfer means 60. The recording medium P to which the toner image is transferred is fixed to the surface of the recording medium P by the fixing unit 70, then discharged upward, and supported by the second supporting unit 20 in the vertical direction.

The printer M having the above structure and operation,
That is, in the printer M having the vertical U-shaped path, the occupied area of the main body 1 can be reduced by shortening the length of the transport path 30 in the front-rear direction, regardless of the length of the recording medium P in the transport direction. Is. By the way, the printer M
Has several heating elements. For example, the fixing unit 70 described above, the control unit 81, which will be described later, the AC input unit 82, the high voltage generation unit 83, the motor 84, and the like are such. On the other hand, it has a member vulnerable to heat, such as the above-mentioned information light emitting means 50 and a developing device 43 having a toner described later. When the conveyance path 30 is shortened to reduce the occupied area, the mounting density of each member increases and each member approaches. The heat-generating member and the heat-sensitive member are arranged close to each other. Therefore, in order to shorten the transport path 30 and reduce the size of the main body 1, it is necessary to solve the problem of heat.

The structure of each member will be described below in order from the first supporting means 10.

The first supporting means 10 is provided at the rear portion of the main body 1, and has an abutting portion 11, a leading end supporting portion 12, and a paper feed tray 13 in this order from below. The abutting portion 11 supports the front end of the recording medium P before image formation from below and supports the weight of the recording medium P. The tip support portion 12 is swingably supported in the front-rear direction by the main body 1 around the shaft 12a, and is urged forward by a spring 12b arranged on the back surface of the lower end portion. The front end support portion 12 biased forward is retracted rearward by a cam member (not shown) before feeding, and the above-mentioned cam member rotates to attach the recording medium P forward only during paper feeding. Energize. The highest recording medium P among the recording media P before feeding is fed by the abutting portion 11 and the separating claws to the feeding position A.
It is positioned at 1 and waits for feeding. When the recording medium P is fed, the next recording medium P is arranged at the feeding position A1 by the tip support portion 12 biased by the spring 12b. The paper feed tray 13 is arranged so as to vertically project from the rear end of the upper surface of the main body 1. The paper feed tray 13 supports the middle portion and the rear end portion of the recording medium P from the back side (rear surface side) of the recording medium P, and supports the entire recording medium P before image formation in a vertical plane. On the front side of the paper feed tray 13, two movable regulating plates 13L and 13R that regulate the position of the recording medium P in the left-right direction (refers to the left and right when viewed from the front side to the rear side), and the manual feed. A manual feed guide 13a for guiding the recording medium P at the time is arranged. In addition, at the upper end of the paper feed tray 13, extending upward,
An extension guide 13b that stably supports the recording medium P having a long length in the transport direction is arranged so that it can move in and out. The paper feed tray 13 is detachably attached to the upper surface of the main body 1. Here, the first supporting angle θ ₁ of the recording medium P before image formation, that is, the abutting portion 11 and the leading end supporting portion 1 described above.
2. The first support angle θ ₁ which is the angle formed by the recording medium P in the state of being supported in a plane by the first supporting means 10 configured by the feeding tray 13 and the like is 60 ° to 90.
By setting the angle to 0, it is possible to contribute to the reduction of the occupied area of the main body 1, and it is also possible to realize good feeding of the recording medium P that effectively utilizes gravity. The first support angle θ ₁ is preferably set to 70 ° to 75 °.

The second supporting means 20 has the above-mentioned first supporting means 10 provided at the rear portion of the main body 1, while the main body 1 has the same structure.
It is provided in the front part of the. The second supporting means 20 is the main body 1
Is provided on the openable / closable exterior cover 2 (the double-dotted line in the figure indicates the exterior cover 2 in the middle of the opening / closing operation), and the abutting portion 21 and the paper discharge order from the bottom. It has a tray 22 and an extension tray 23. With respect to the recording medium P on which an image has been formed, the abutting portion 21 supports the rear end from below, the paper ejection tray 22 supports the latter half of the rear side, and the extension tray 23 supports the front half of the rear side. . Extension tray 2
3 is supported by a paper discharge tray 22 so as to be able to move up and down, and is extended tray 23 above the main body 1.
And the discharge tray 22 support the recording medium P on which an image has been formed in a plane shape in the vertical direction. The angle with respect to the horizontal plane of the recording medium P in the state of being supported in the vertical direction is defined as the second
Assuming that the support angle is θ ₂ , the second support angle θ ₂ is 55
Set to ° to 75 °. Note that this second support angle θ ₂
Is preferably set to 65 ° to 70 °. The opening / closing operation of the exterior cover 2 having the paper discharge tray 22 and the like will be described later together with the attaching / detaching operation of the process cartridge 40.

The transport path 30 connects the lower end portion 10a of the first supporting means 10 and the lower end portion 20a of the second supporting means 20,
A path for transporting the recording medium P extending from the rear part to the front part of the main body 1 is configured. The transport path 30 is separated from the rear portion (upstream side) to the front portion (downstream side) in order.
1, pre-transfer guides 32a and 32b, post-transfer guide 33
a, 33b, and the reverse guide 34 on the downstream side of the fixing unit 70. Also, diagonally above the separation pad 31,
A paper feed roller 35 is arranged, and a conveyance roller 36 is arranged below the paper feed roller 35. Paper feed roller 35
Has an outer peripheral surface eccentrically formed with respect to the shaft 35a, and is rotated in the direction of arrow R35 so that the first support means 10
The uppermost recording medium P is fed from the above to prevent the double feeding of the recording medium P between the separation roller 31 and the conveyance roller 36.
Together with this, the recording medium P is configured to be conveyed. The pre-transfer guide 32a on the upstream side is configured to move gently downward, and the pre-transfer guide 32b on the downstream side is configured to be substantially horizontal, and the lower surface 4 of the upper process cartridge 40 is formed.
0a to guide the recording medium P to the photosensitive drum 41
And the transfer roller 61 of the transfer unit 60. The post-transfer guide 33a is formed on the inclined surface which is inclined downward to the front, and the post-transfer guide 3 which is continuous with this is formed.
3b has a gentle concave surface. The recording medium P after the toner image transfer is guided to the fixing position A3 formed between the fixing film of the fixing unit 70 and the pressure roller (both will be described later) by the post-transfer guides 33a and 33b. In addition, on the most upstream side of the post-transfer guide 33a, a charge removing member 33c that removes excess charges of the recording medium P after the toner image transfer is attached. The reversing guide 34 is a gently curved guide that is provided between the transport roller 37 immediately downstream of the fixing unit 70 and the paper discharge roller 38 above the transport roller 37, and guides the recording medium P after fixing the toner image upward. Guide toward the second support means 20. In addition, this inversion guide 34
Is integrally formed with the exterior cover 2 described above.

As described above, the feeding path A1, the transfer position A2, and the fixing position A are arranged in this order on the conveying path 30 from the upstream side.
3 are provided, but these positions A1, A2, A3
Are set to be sequentially arranged in this order at lower positions. Therefore, at the time of image formation, these positions A1,
The recording medium P that sequentially passes through A2 and A3 is at a high place (A1).
Therefore, the sheets are sequentially conveyed to a low place (A3), and smooth conveyance is performed according to gravity. Furthermore, since the leading end of the recording medium P at this time is supported from below by the pre-transfer guides 32a, 32b and the post-transfer guides 33a, 33b, these guides 32a, 32b, 33a, 33 are provided.
Following b, the paper is conveyed in a stable posture. For this reason, it is surely introduced into the transfer position A2 and the fixing position A3, and the conveyance failure such as paper jam is well prevented.

In the process cartridge 40, a photosensitive drum 41, a charging roller (charging means) 42, a developing device (developing means) 43, and a cleaning device (cleaning means) 44 are integrated into a cartridge container 45 to form a cartridge. It is detachable from the main body 1. The photosensitive drum 41 is a drum-shaped electrophotographic photosensitive member as described above, and includes a motor 84 (described later) on the main body 1 side.
Is driven to rotate in the direction of arrow R41. The charging roller 42 is disposed in contact with the surface of the photosensitive drum 41, and is driven to rotate as the photosensitive drum 41 rotates in the direction of arrow R41. A charging voltage in which a DC voltage and an AC voltage are superposed is applied to the charging roller 42 by the high voltage generating unit 83 on the substrate 80 on the main body 1 side, and the rotation of the photosensitive drum 41 causes the surface of the photosensitive drum 41 to move. It is uniformly charged. The developing device 43 has a toner container 43a for containing toner and a developing sleeve 43b. The developing sleeve 43b has a magnet inside and carries toner on the surface by rotating. The layer thickness of the toner on the surface is regulated by the regulation blade 43c and an electric charge is applied to the toner, and the toner is attached to the electrostatic latent image formed on the photosensitive drum 41 by the information light emitting unit 50, which will be described later.
Form a toner image. In the process cartridge 40 according to the present embodiment, the developing device 43 can arrange the toner container 43a on the upper side and the developing sleeve 43b on the lower side. Therefore, the toner in the toner container 43a naturally develops due to gravity. It drops toward the sleeve 43b. Therefore, it is not necessary to attach a special mechanism for conveying the toner in the toner container 43a toward the developing sleeve 43b, such as a stirring member. As a result, the structure of the process cartridge 40 can be simplified. The cleaning device 44 includes a cleaning blade 44a that rubs the surface of the photosensitive drum 41 after the toner image transfer to remove residual toner on the surface, and a cleaning container 44b that collects the removed waste toner. A through hole 45a for exposure is formed in the upper portion of the cartridge container 45. The operation of attaching / detaching the process cartridge 40 to / from the main body 1 will be described later.

The information light emitting means 50 irradiates the surface of the photosensitive drum 41 with light through the above-mentioned through hole 45a for exposure, and is disposed above the process cartridge 40 as a whole. The information light emitting means 50 includes a semiconductor laser 55 that oscillates a laser beam based on an image signal, and a polygon mirror 51 that reflects the laser beam while rotating it.
And a motor 52 for rotating the polygon mirror 51,
The lens 53 and the reflection mirror 54 are provided. The information light emitting means 50 includes a polygon mirror 51 and a first supporting means 1.
The reflecting mirror 54 is disposed on the 0 side (rear side) and downward, and on the second supporting means 20 side (front side) and upward. In other words, the whole is arranged in the front upward direction, contrary to the above-mentioned transport path 30. By arranging in this way, it is possible to prevent the height of the main body 1 from becoming high, and in a compact configuration, the required optical path length of the laser beam from the polygon mirror 51 to the photosensitive drum 41 via the reflection mirror 54 is reduced. It is possible to secure the position and to set the mounting position of the manual insertion guide 13a of the first supporting means 10 to a position where operability is good. By the irradiation of this laser beam, the photosensitive drum 41
An electrostatic latent image corresponding to the image signal is formed on the top.

The process cartridge 40 and the information light emitting means 50 described above are arranged between the rear first supporting means 10, the front second supporting means 20, and the lower conveying path 30, that is, a vertical U-shaped path. It is compactly placed in the inner space.

The transfer means 60 includes a transfer roller 61 which is in contact with the photosensitive drum 41 from below under the transport path 30.
And a transfer position A2 is formed between the photosensitive drum 41 and the photosensitive drum 41. The left and right ends of the cored bar 61a of the transfer roller 61 are respectively held by bearings 63 urged by springs 62, so that the transfer roller 61 is brought into contact with the surface of the photosensitive drum 41 with a predetermined pressing force. A transfer voltage having a polarity opposite to that of the toner image on the photosensitive drum 41 is applied to the transfer roller 61 by the high-voltage generating unit 83 on the substrate 80.
The toner image on the photosensitive drum 41 is transferred onto the surface of the recording medium P passing through the transfer position A2.

The fixing means 70 fixes the ceramic heater 72 held by the main body 1 via the spring 71, the fixing film 74 endlessly mounted on the outer periphery of the guide 73, and the fixing film 74 by abutting the fixing film 74 from below. It has a pressure roller 75 that forms a fixing position A3 with the film 74. Since the ceramic heater 72 and the fixing film 74 have small heat capacities, it takes a short time to heat up to a predetermined temperature required for fixing after energization. This prevents unnecessary heat from being radiated from the fixing means 70. The fixing unit 70 melts and fixes the toner image when the recording medium P having the toner image transferred on the surface at the upstream transfer position A2 passes the transfer position A3 while carrying the unfixed toner image. And is fixed on the surface of the recording medium P.

The lower part of the main body 1, that is, the above-mentioned transport path 30.
A board (electrical equipment board) 80 is disposed below.
The control unit 8 is arranged on the substrate 80 in order from the downstream side (front side).
1, an AC input section 82, a high voltage generation section 83, and a motor 84 are arranged, and the height dimensions of these are sequentially increased in this order. That is, among the members on the substrate 80, tall members are arranged at the rear part and short members are arranged at the front part. This is consistent with the configuration of the transport path 30 described above, where the rear side is high and the front side is low. That is, the arrangement of each member on the substrate 80 is determined according to the space below the transport path 30. This contributes to downsizing of the main body 1.

Next, the opening / closing operation of the outer cover 2 of the main body 1 and the mounting operation of the process cartridge 40 will be described with reference to FIG.

While covering the front surface of the main body 1, the above-mentioned second
The outer cover 2 that also serves as the supporting means 20 is supported by the main body 1 so as to be swingable in the direction of arrow R2 around the lower hinge 2a. When the exterior cover 2 is opened as shown in the figure, a large opening 1a is exposed on the front surface of the main body 1. The process cartridge 40 is mounted inside the main body 1 through the opening 1a. At this time, the conveyance path 30 in the lower part of the space where the process cartridge 40 is mounted.
Is composed in a downward direction. On the other hand, since the information light emitting means 50 above the space is arranged on the upper side in the opposite direction to the transport path 30, the opening 1a is opened large, and the mounting operation of the process cartridge 40 is extremely easy. Will be things. The process cartridge 40 mounted in the main body 1 can be easily removed in the same manner. Further, when the process cartridge 40 is removed, the transport path 3
A portion of 0 from the feeding position A1 to the fixing position A3 is exposed, and jam processing of the recording medium P and the like can be easily performed.

Next, with reference to FIG. 3, an image forming operation of the entire printer M having the above configuration will be briefly described.

First, the recording medium P is set on the first supporting means 10 in the vertical direction. The photosensitive drum 41 in the process cartridge 40 is rotationally driven, and by the charging roller 42,
The surface of the photosensitive drum 41 is uniformly charged with, for example, a negative polarity.
The information light emitting means 50 exposes the uniformly charged surface of the photosensitive drum 41. Laser light based on an image signal is emitted from the information light emitting means 50 to irradiate the surface of the photosensitive drum 41. Negative charges are removed from the light-irradiated portion on the photosensitive drum 41 to form an electrostatic latent image. This electrostatic latent image becomes a toner image by so-called reversal development in which toner of negative polarity is attached by the developing device 43.
On the other hand, the recording medium P, which has waited with its leading end aligned with the sheet feeding position A1, is supplied to the transfer position A2 by the sheet feeding roller 35 so as to match the timing with the toner image on the photosensitive drum 41. At the transfer position A2, by the transfer roller 61 to which a transfer voltage having a positive polarity opposite to that of the toner is applied,
The toner image on the photosensitive drum 41 is transferred onto the recording medium P. In the fixing means 70, the unfixed toner image on the surface of the recording medium P is fixed by being heated and pressed. The recording medium P on which the toner image has been fixed is vertically ejected onto the second supporting unit 20 by the paper ejection roller 38 via the reversing path 34.

In the printer M of this embodiment, the recording medium P before the image formation and the recording medium P after the image formation are respectively supported by the first supporting means 10,
The occupied area of the main body 1 is reduced by vertically supporting the second support means 20 and shortening the transport path 30.

When shortening the transport path 30, FIG.
Various heat countermeasures are taken as shown in. The heat countermeasure will be described below.

The main heat generating portion of the printer M shown in FIG. 1 is the fixing means 70 having the ceramic heater 74. The hood 3 is covered above the fixing means 70. The hood 3 has an upper plate 3a that covers the upper side of the fixing device 70 and a front plate 3b that covers the front side. The upper plate 3a is configured so as to move upward and guide the heat flow from the fixing means 70 to the front side. In addition, the front plate 3b is provided with exhaust holes 3c on the upper and lower sides.
A large number of holes are formed in the stepwise direction. A guide plate 3d directed forward is provided below each exhaust hole 3c,
The heat flow H1 discharged from the exhaust hole 3c is guided and further guided toward the front exterior cover 2. The exterior cover 2 is divided into a lower half portion 2c and an upper half portion 2d with the step portion 2b as a boundary.
A large number of exhaust holes 2e are formed in the front surface of the lower half portion 2c. The heat flow H1 from the hood 3 described above passes through these exhaust holes 2e and is discharged to the outside of the main body 1. On the other hand, on the rear side of the upper half 2d of the exterior cover 2, the second heat exhaust duct D2 is provided.
Are formed. The front, rear, left and right of the second exhaust heat duct D2,
Each of them is constituted by the back surface of the paper discharge tray 22 of the above-mentioned second supporting means 20, the partition wall 4, and the left and right side walls (not shown) which form a part of the main body 1. The partition wall 4 is provided in the space above the above-mentioned transport path 30 so that the process cartridge 40
Together with the cleaning container 44b of the cartridge container 45, the fixing unit 70 side and the photosensitive drum 41 side are thermally blocked. By doing so, the developing device 43 and the information light emitting means 50 of the process cartridge 40, which are likely to deteriorate in performance particularly in a high temperature environment, are thermally isolated from the fixing means 70. The second exhaust heat duct D2 has a wide lower end inlet Da, is arranged directly above the fixing means 70 and the hood 3, and rises along the back surface of the paper discharge tray 22, and at the same time of the main body 1. Exit D on top
b. Hood 3 heated by fixing means 70
The heat on the upper surface becomes a heat flow H2, is guided to the inlet Da of the second heat exhaust duct D2, rises inside thereof, and is discharged from the outlet Db. In the present embodiment, since the paper discharge tray 22 is configured in the vertical direction as described above, the rear surface of
It can be used as a part of the exhaust heat duct D2. Therefore, the second exhaust heat duct D2 can be easily configured only by additionally configuring the partition wall 4. Further, in this embodiment, the paper discharge tray 22 and the partition wall 4 are formed integrally with the outer cover 2, that is, the second heat exhaust duct D2 is formed integrally with the outer cover 2. Therefore, as shown in FIG. 2 described above, when the exterior cover 2 is opened, the second heat exhaust duct D2 moves with it, and does not hinder the attachment / detachment of the process cartridge 40 to / from the main body 1.

As described above, the heat from the fixing means 70 is
Hood 3 and its exhaust hole 3c, exhaust hole 2 of exterior cover 2
The heat flow H1 due to e and the like and the heat flow H2 due to the second heat discharge duct D2 are favorably discharged to the outside of the main body 1. Therefore, it becomes possible to dispose the process cartridge 40 close to the fixing unit 70, and thus the length of the transport path 30 can be shortened.

Next, processing of heat from the heat-generating component of the substrate 80 arranged below the transport path 30 will be described. As a heat generating member, a control unit 81, an AC input unit 82, a high voltage generation unit 83, 8 are provided on the substrate 80 arranged below the transport path 30.
5, there is a motor 84. The heat generated from these forms a heat flow H3, which moves rearward along the lower surface of the transport path 30 which is configured to fall forward (backward) and is discharged from the rear portion of the main body 1. In the rear part of the main body 1, a rear plate 5 which is a part of the main body 1 and is located on the back surface of the above-mentioned first supporting means 10, a rear face plate 6 which also constitutes a part of the main body 1, and left and right side plates (not shown). The first exhaust heat duct D1 surrounded by the front and rear and the left and right is constituted by (illustration). First exhaust heat duct D1
Is configured such that the inlet Da at the lower end is wide, the intermediate portion is substantially upright, and the outlet Db opening on the upper surface of the main body 1 is small. Further, the above-mentioned rear surface plate 6 has a step portion 6a at approximately the middle in the vertical direction, and a large number of exhaust holes (vent holes) 6b penetrating in the vertical direction are formed in the step portion 6a. The step portion 6a is configured so as to project laterally (toward the rear in the same figure) in the lower portion of the main body 1, and inside the step portion 6a, among the members on the substrate 80, Members that generate a lot of heat are arranged. In addition, the front and rear sides of the bottom surface 7 of the main body 1, that is,
Intake holes (not shown) are provided below the control unit 81 and below the high pressure generation unit 85, respectively.

With the above configuration, the heat from the heat-generating component on the substrate 80 becomes the heat flow H3 and moves rearward along the lower surface of the transport path 30. Further, in the rear part, it rises as a heat flow H4, rises in the first exhaust heat duct D1 as a heat flow H5, or passes through the exhaust hole 1e as a heat flow H6 and is discharged to the outside of the main body 1. In parallel with the discharge of these heat flows H5 and H6, cold air C1 and C2 are introduced into the main body 1 from the front side and the rear side of the bottom surface 7, respectively.

As described above, the heat treatment of the main body 1 is performed above and below the transport path 30 as a reference.
That is, different processing is performed inside and outside the vertical U-shaped path. On the inner side, first, the fixing means 70 is thermally shielded from the process cartridge 40, and one of the heat from the fixing means 70 is transferred to the main body 1 as a heat flow H1 via the exhaust hole 2e of the outer cover 2 or the like. On the front, the other is the heat flow H2
Is discharged above the main body 1 through the second heat exhaust duct D2. On the other hand, on the outer side of the vertical U-shaped path, first, the transport path 30 prevents the heat flow from the member on the substrate 80 from entering the process cartridge 40 side (inside the vertical U-shaped path). Along the lower surface of the transport path 30 that is rising backward, the heat flow H3 is moved backward,
Together with the rearward heat flow H4, the heat flow H5 is discharged from the first exhaust heat duct 1 or the heat flow H6 from the exhaust hole 6b to the rear of the main body 1. In addition, according to the present embodiment, as described above, an effective flow of the heat flows H1 to H6 can be formed by the first exhaust heat duct D1 and the second exhaust heat duct D2, and the lower surface of the transport path 30, so It is not necessary to mount an exhaust heat fan or the like for forming a heat flow, which was required.

As described above, by forming a good flow of the heat flows H1 to H6, the process cartridge 40 and the fixing means 70 can be arranged close to each other, and as a result, the transport path 30 can be shortened. it can. This transport path 3
In addition to being able to shorten 0, as described above, by supporting the recording medium P before and after image formation in the vertical direction by the first supporting means 10 and the second supporting means 20, respectively, the occupied area of the main body 1 can be reduced. It becomes possible to do. <Second Embodiment> FIGS. 4 and 5 are a longitudinal sectional view and a plan view, respectively, showing a second embodiment. In the present embodiment, a louver is provided as the exhaust hole 6b on the upper surface of the stepped portion 6a, and the stepped portion 6a is not provided over the entire left-right direction of the main body 1, but the cutout portion 6L is provided on the left end side and the cutout portion 6R is provided on the right end side. Is provided.

The louver 6b on the upper surface of the stepped portion 6a is provided on the substrate 8
Since it is arranged immediately above the member 80A that generates a lot of heat when moving, its heat exhausting effect is high.

A board 80 is arranged on the left side of the lower part of the main body 1, and a controller board 80a is arranged on the right side. The controller board 80a is disposed on the same plane as the board 80, and the connector 80 is mounted on the board 80.
connected via g. An interface connector 80b is connected to the controller board 80a from the rear side, and is further connected to an external computer (not shown) or the like via an interface cable 80c. The controller board 80 a processes the image signal and the control signal sent from the computer and outputs them to the board 80. On the other hand, a power connector (inlet portion) 80 d is connected to the substrate 80 from the rear side, and is connected to a power source (not shown) via a power cord 80.

Generally, when the power cable 80e and the interface cable 80c are connected to the main body 1, the length from the connecting portion to the bent portion, that is, the length of the rigid portion has been a cause of increasing the installation space. However, according to this embodiment, the occupied area is not increased. Figure 5
Then, the length L of the power connector 80d and the power cord 80e
The portion 1 and the portion of the interface connector 80b having the length L2 are made rigid, but by arranging them in the cutout portions 6L and 6R provided in the stepped portion 6a of the main body 1, respectively, the occupied area is increased. To prevent.

In this embodiment, the controller board 80
Although an example in which a is separated from the substrate 80 that controls the main body 1 is shown, the same effect can be obtained even when both are configured on the same substrate.

The power cord 80e may be a right angle one as shown in FIG. 6 to form the inred portion as shown in FIG. <Third Embodiment> In the above embodiments, the information light emitting means 5 is used.
As 0, instead of emitting a laser beam, L
It is also possible to use an ED array. Photosensitive drum 41
By arranging a large number of LEDs along the generatrix of the surface of the photosensitive drum 41 and rotating the charged photosensitive drum 41, ON / OFF of each LED is selected on the basis of an image signal. It forms an electrostatic latent image on it. According to this, the configuration can be further downsized and simplified. <Embodiment 4> Embodiments of the members constituting the process cartridge 40 are not limited to those shown in FIG. For example, an electrophotographic photosensitive member as an image carrier and at least one of a charging unit, a developing unit, and a cleaning unit as a process unit are integrally made into a cartridge and detachable from the main body of the image forming apparatus. May be.

Further, the electrophotographic photosensitive member as the image carrier and the charging means, the developing means or the cleaning means as the process means are integrally made into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. Alternatively, at least the developing means and the electrophotographic photosensitive member as the image bearing member may be integrally formed into a cartridge so as to be detachable from the main body of the image forming apparatus. <Embodiment 5> The first supporting means 10 of the above embodiments may be configured mainly by a paper feed cassette. A vertical cassette mounting portion is provided at the rear portion of the main body 1, and a paper feed cassette containing the recording medium P is mounted from above the cassette mounting portion to support the recording medium P in the vertical direction. is there. In this case, the cassette mounting portion and the paper feed cassette constitute the first supporting means.

[0056]

As described above, according to the present invention,
The temperature rise can be prevented by providing a step portion having a vent hole on the upper surface in the lower part of the apparatus main body and disposing the heat-generating member of the electrical equipment substrate on this step portion.

The recording medium before and after the image formation is vertically supported by the first supporting means and the second supporting means, respectively.
Further, by providing a cutout portion for connecting the interface connector and the inlet portion to the above step portion, the area occupied by the apparatus main body can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a first exemplary embodiment.

FIG. 2 is an operation explanatory diagram illustrating an opening / closing operation of an outer cover and a process cartridge mounting operation in the first embodiment.

FIG. 3 is a vertical cross-sectional view showing how heat is exhausted by a heat flow in the image forming apparatus according to the first embodiment.

FIG. 4 is a vertical sectional view showing a schematic configuration of an image forming apparatus according to a second embodiment.

FIG. 5 is a plan view showing the configuration of the image forming apparatus according to the second embodiment.

FIG. 6 is a plan view showing the configuration of another inlet portion of the second embodiment.

FIG. 7 is a vertical cross-sectional view showing a schematic configuration of a conventional image forming apparatus.

FIG. 8 is a plan view showing the configuration of a conventional image forming apparatus.

[Explanation of symbols]

1 Image Forming Apparatus Main Body (Printer Main Body) 2 Exterior Covers 2e, 3c Exhaust Hole 3 Hood 4 Partition 5 Back Plate 6 Rear Plate 6a Step 6b Vent (Exhaust) 6L, 6R Cutout 10 First Support Means 20 2nd Supporting means 30 Conveying path 40 Process cartridge 41 Image carrier (photosensitive drum) 42 Charging means (transfer roller) 43 Developing means (developing device) 44 Cleaning means (cleaning device) 45 Cartridge container 50 Information light emitting means 51 Polygon mirror 60 Transfer Means 61 Transfer roller 70 Fixing means 72 Ceramic heater 74 Fixing film 75 Pressure roller 80 Electrical equipment board (board) 80a Controller board 80b Interface connector 80c Interface cable 80d Power connector 80e Power cord 81 Control section 82 AC input section 8 3,85 High-pressure generator 84 Motor C1, C2 Cold air D1 First exhaust heat duct D2 Second exhaust heat duct Da Inlet Db Outlet H1 to H6 Heat flow M Image forming device (laser beam printer) P Recording medium θ ₁ First support angle θ ₂ Second support angle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location // G03G 21/20 G03G 15/00 554 21/00 534 (72) Inventor Tatsuo Hamada Ota, Tokyo 3-30-2 Shimomaruko, Tokyo Canon Inc. (72) Ken Shinmura 3-30-2 Shimomaruko, Ota-ku, Tokyo Metropolitan area (72) Inventor Jun 3 Tsumomaruko, Ota-ku, Tokyo No. 30-2 Canon Inc. (72) Inventor Yoshihiro Matsuo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (15)

[Claims] 1. An image forming apparatus for forming an image on a recording medium, comprising: first supporting means for vertically supporting a recording medium for feeding; and second supporting means for vertically supporting the recording medium after image formation. Supporting means, an image carrier provided above a transport path from the first supporting means to the second supporting means, and the image carrier between the first supporting means and the second supporting means. An information light emitting unit provided above the image carrier for giving information light corresponding to image information to the image carrier, and a toner image formed on the image carrier provided below the transport path. A transfer unit for transferring to the recording medium, a fixing unit for fixing the toner image transferred on the recording medium to the recording medium, and an electric board having a heat generating member on the upper surface and arranged below the transport path. And the top of the device while projecting laterally at the bottom It includes a stepped portion vent hole is drilled, the heat generation member of the electrical component mounting board is placed the electrical component mounting board so as to be located in the step portion, that the image forming apparatus according to claim. 2. The image forming apparatus according to claim 1, wherein the stepped portion is provided with a cutout portion for connecting an inlet portion. 3. The image forming apparatus according to claim 1, wherein the stepped portion is provided with a cutout portion for connecting an interface connector. 4. A feeding position for feeding the recording medium supported by the first supporting means, a feeding position for feeding the recording medium supported by the first supporting means, a transfer position by the transferring means, and the fixing means, which are sequentially arranged from the upstream side to the downstream side of the conveying path. The image forming apparatus according to any one of claims 1 to 3, wherein the fixing position by the means is arranged at a lower position in this order. 5. The fixing unit has a heating unit, which rises along the back surface of the second supporting unit for discharging heat from the heating unit and has an outlet at the upper part of the image forming apparatus main body. The image forming apparatus according to claim 1, further comprising two exhaust heat ducts. 6. The second exhaust heat duct has a partition wall that thermally blocks heat from the fixing unit from reaching the image carrier above the transport path. Item 5. The image forming apparatus according to item 5. 7. The image forming apparatus according to claim 1, wherein the second supporting unit also serves as an outer cover that can be opened and closed with respect to the image forming apparatus main body. 8. The second supporting means also serves as an exterior cover that can be opened and closed with respect to the image forming apparatus main body.
The image forming apparatus according to claim 5, wherein the exhaust heat duct is provided integrally with the exterior cover. 9. The electrical component board includes a control unit, a high voltage generation unit, and an AC input unit, and the control unit is located on the downstream side, and the high voltage generation unit and the AC input unit are located on the upstream side. A motor is provided below the feeding position for feeding the recording medium supported by the first supporting means, and a motor is provided above the motor along the back surface of the first supporting means. The image forming apparatus according to claim 1, further comprising a first exhaust heat duct. 10. The image forming apparatus according to claim 1, wherein the information light emitting unit emits a laser beam. 11. The information light emitting means includes a semiconductor laser, a polygon mirror, a lens, and a reflection mirror, and the polygon mirror is supported on the side of the first support means and the reflection mirror is supported on the second side. 11. The image forming apparatus according to claim 10, wherein the image forming apparatus is arranged on the device side, the polygon mirror is arranged below, and the reflection mirror is arranged above. 12. The image forming apparatus according to claim 1, wherein the information light emitting unit has an LED array arranged so as to face the image carrier. 13. The image carrier comprises an electrophotographic photosensitive member as the image carrier and at least one of a charging unit, a developing unit, and a cleaning unit, which are integrally formed as a cartridge with respect to the main body of the image forming apparatus. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided in a process cartridge that is detachable. 14. The image carrier can be detachably attached to an image forming apparatus main body by integrally forming an electrophotographic photosensitive member as the image carrier and a charging unit, a developing unit, or a cleaning unit into a cartridge. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided in the process cartridge. 15. The image carrier is provided in a process cartridge in which at least a developing unit and an electrophotographic photosensitive member as the image carrier are integrally made into a cartridge and detachable from the main body of the image forming apparatus. The image forming apparatus according to claim 1, wherein: