JP2004233452A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that prevents scattering of toner from the vicinity of photoreceptor and, at the same time, efficiently restricts an increase in the temperature in the apparatus which is caused by dissipation of heat from various electrical devices, for instance, a fixing device. <P>SOLUTION: The apparatus includes a first air flow channel that ventilates the vicinity of the fixing device 111 and a second air flow channel that flows in the back of the main body of the image forming apparatus towards the fixing device. Also, the air flow channels are each disposed so as to be shut off from spaces around the photoreceptor drums 11a to 11d. In addition, by disposing the belt body such as an intermediate transfer belt within the air flow channels, the photoreceptor drums 11a to 11d are cooled via the belt body. Further, each air flow channel is provided with an opening/closing port, thereby ventilating the vicinity of the photoreceptor drums 11a to 11d only when image formation is not carried out. Such a device structure realizes efficient ventilation and prevention of toner scattering from the photoreceptor drums 11a to 11d caused by ventilation of the inside of the apparatus. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus for forming a toner image on a transfer material.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a color image forming apparatus employed in a copying machine, a printer, and the like, a toner image formed by a plurality of image forming units is temporarily superimposed on an intermediate transfer body, and then transferred to a recording material at once. 2. Description of the Related Art An intermediate transfer type image forming apparatus is known.
[0003]
An intermediate transfer type image forming apparatus of this type will be specifically described with reference to FIG.
[0004]
First, a plurality of image forming units that form latent images on the photosensitive drums 211a to 211d serving as image carriers using light, magnetism, electric charges, and the like, and visualize the latent images to obtain visible images, An intermediate transfer member 2132 that forms a multi-color image based on a visible image sequentially transferred from a forming unit; a transfer unit 272 that transfers the multi-color image on the intermediate transfer member 2132 to a recording material; And a fixing device 2111 for fixing the multi-color image on the recording material.
[0005]
As the intermediate transfer member 2132, a belt-shaped intermediate transfer belt stretched around a plurality of rollers and rotating endlessly, a cylindrical intermediate transfer drum rotating around a drum shaft, or the like is used. In the image forming process, the visible image formed on the photosensitive drum is arranged at a position facing the image forming unit and the intermediate transfer body by the intermediate transfer body 2132 approaching the plurality of image forming units. The primary transfer is performed on the intermediate transfer member 2132 by the primary transfer charging devices 2104a to 2104d. The visible images primary-transferred from the plurality of photosensitive drums are superimposed on the intermediate transfer member, and are conveyed to a position where the image is transferred to a recording material by rotating the intermediate transfer member. The visible image on the intermediate transfer body 2132 is secondarily transferred to a fed recording material at a transfer position by a secondary transfer charging device, and further fixed by the fixing unit 2111. Thus, a full-color image is obtained. When a single-color image is obtained, a single-color visible image is primarily transferred from a specific image forming unit onto an intermediate transfer member, and then a single-color image is obtained through the same process as when a full-color image is formed.
[0006]
A so-called latent image is formed on the photoreceptor by the exposure devices 260a to 260d, and the latent image is developed with a powdery toner. The toner is stored in developing devices 214a to 214d arranged close to the respective photoconductors, and develops a latent image on the photoconductor by applying a high voltage to the developing devices.
[0007]
The photoconductor, the developing device, the intermediate transfer belt, and the like are rotationally driven by a driving source such as a motor.
[0008]
The fixing device 2111 includes a fixing roller 2111a in which a heater is housed, and a pressing roller 2111b for pressing the fixing roller 2111a.
[0009]
When a sheet (recording material) as a transfer material is conveyed through the fixing device, the sheet is heated by a heater and pressed by a pair of rollers, so that the toner image on the sheet is melted and fixed on the sheet. become.
[0010]
By the way, in the conventional image forming apparatus configured as described above, the temperature of a fixing device or a motor as a driving unit for driving a photoconductor or a developing device is increased, or power is supplied to the entire image forming apparatus. It is known that the temperature inside the device rises due to the influence of heat from electric components such as a power supply device for the purpose, and various problems occur.
[0011]
That is, when the temperature around the photoreceptor rises (hereinafter, referred to as temperature rise), the fluidity of the toner deteriorates, and the physical property value changes, thereby hindering the image forming process, resulting in image failure. In some cases, the toner hardens in the developing device. Alternatively, in an exposure apparatus that irradiates a photoreceptor, glass, plastic, or the like is usually used as a material of a lens or the like, but the optical performance of those optical components changes due to a rise in temperature, and an image defect occurs. . Also, a power supply device for supplying power to the entire image forming apparatus, a controller for controlling the entire image forming apparatus, a high voltage unit for applying a high voltage to the image forming unit, a photoconductor, a developing device, an intermediate transfer belt, and the like. The so-called electric parts and electric parts, such as motors as a drive source for driving, are likely to be damaged when the temperature rises to a certain temperature or higher, such as semiconductors and the like that constitute them. is there.
[0012]
For this reason, in a conventional image forming apparatus, as a countermeasure for increasing the temperature inside the apparatus, it is common to provide a heat exhaust (exhaust) means as in the apparatus described in Patent Document 1, for example (see FIG. 5).
[0013]
As shown in FIG. 5, in such an image forming apparatus, the heat inside the apparatus around the photoconductor is mainly exhausted by using an exhaust unit such as a fan, and the airflow is caused to flow around the photoconductor. In many cases, ozone products generated when the body is charged are simultaneously discharged outside the apparatus. If the ozone product generated when charging the photoreceptor is left as it is, the product adheres to the photoreceptor surface and causes image defects. It is.
[0014]
[Patent Document 1]
JP-A-7-104617
[0015]
[Problems to be solved by the invention]
However, adopting such an apparatus configuration causes a further problem.
[0016]
That is, there is a problem in that, by generating an airflow around the photoconductor, a toner image for developing the latent image on the photoconductor is scattered, and the inside of the apparatus is soiled.
[0017]
If the scattered toner contaminates the inside of the machine, an electrical contact failure occurs.If the scattered toner reaches the exposure device, the optical components such as the lenses described above are contaminated, causing image defects. Or Of course, a user who uses the apparatus may have a considerable discomfort such as dirty hands during use. Further, when the toner scattered inside the apparatus is discharged outside the apparatus together with the heat discharged outside the apparatus, there is a problem that the periphery of the image forming apparatus is soiled.
[0018]
The present invention has been made in view of such circumstances, and an object of the present invention is to prevent toner from escaping from the periphery of a photoreceptor, and to fix a device caused by heat radiation from various electric components such as a fixing device. It is an object of the present invention to provide an image forming apparatus capable of efficiently suppressing the temperature rise in the inside.
[0019]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a photoconductor, an exposure unit that exposes the photoconductor, a developing unit that develops a latent image on the exposed photoconductor as a toner image, and the developing unit. An image forming apparatus that performs an image forming process on a transfer material having a transfer unit that transfers the formed image onto the transfer material, and a fixing unit that melts the toner image on the transfer material and fixes the toner image on the transfer material. As a first air path, a driving unit that drives the photoconductor or the developing unit and a photoconductor are formed to form an air path in a direction orthogonal to the longitudinal direction of the photoconductor and toward the fixing unit. A first wall separating the fixing unit and a second wall separating the fixing unit and the photoconductor as a second air passage so as to form an air passage extending in a longitudinal direction of the fixing unit; It is characterized by the following.
[0020]
Note that the present invention is preferably applied to a color image forming apparatus having a plurality of photoconductors.
[0021]
In addition, the first wall may be configured to form at least a part of the first air passage. In addition, the second wall may be configured to form at least a part of the second air path.
[0022]
In addition, it is preferable to have at least one opening and closing port that is opened and closed so as to open and close the communication between the first air path and the second air path, and control means that controls opening and closing of the opening and closing port.
[0023]
Further, it is preferable that a third wall separating the exposure unit and the photoconductor is provided.
[0024]
Further, it is preferable to have a first opening and closing port configured to be openable and closable on the first wall, and control means for controlling opening and closing of the first opening and closing port.
[0025]
Further, it is preferable to have a second opening and closing port configured to be openable and closable on the second wall, and control means for controlling opening and closing of the second opening and closing port.
[0026]
Further, a driving unit for driving the photoconductor or the developing unit is disposed in the first air path, and a motor as a component of the driving unit is compared with other components of the driving unit. It is preferable to dispose it at the most upstream side along the first air path and at the position farthest from the fixing unit.
[0027]
A power supply unit that supplies power to the image forming apparatus; and an electrical unit including a control controller board that controls the image forming apparatus. At least one of the power supply unit and the electrical unit includes It is preferable to arrange in the first air path or the second air path.
[0028]
A first exhaust unit for forcibly generating an airflow in the first air passage to discharge air in the image forming apparatus to the outside; and a forcibly generating an airflow in the second air passage. It is preferable that a second exhaust unit that discharges air in the image forming apparatus to the outside is provided on a side surface of the image forming apparatus.
[0029]
Further, it is preferable that the first exhaust unit is disposed immediately adjacent to the fixing unit.
[0030]
Also, an operation unit for operating the image forming apparatus from the outside is arranged on one side of the apparatus, and the first exhaust unit and the second exhaust unit are arranged on the opposite side of the image forming apparatus. Is preferred.
[0031]
Further, it is preferable to have a detecting means for detecting the temperature in the image forming apparatus.
[0032]
Further, it is preferable that a plurality of photoconductors including at least a photoconductor carrying a yellow-based image be provided, and the photoconductor carrying the yellow-based image be disposed in close proximity to the opening / closing opening.
[0033]
The image forming apparatus further includes a plurality of photoconductors arranged in series, and the transfer unit faces the plurality of photoconductors arranged in series and primarily transfers a toner image on the photoconductor to a transfer material. And an endless intermediate transfer belt for secondary transfer, and a part of the intermediate transfer belt preferably forms a part of the second wall.
[0034]
According to each of the above-described configurations, it is possible to suppress a rise in temperature inside the apparatus and prevent toner from scattering around the photoconductor. Further, it is possible to eliminate ozone products generated around the photoconductor.
[0035]
Further, the temperature rise of the drive source such as a motor is suppressed, and the damage to the drive source can be prevented.
[0036]
In addition, a power supply unit for supplying power to the image forming apparatus and an electrical unit such as a controller board for controlling the image forming apparatus are arranged in the first air passage, so that various electric components in the electrical unit can be elevated. The temperature is suppressed, and damage to parts can be prevented.
[0037]
Further, according to the configuration having the exhaust means for forcibly generating the airflow in the first air passage or the second air passage, it is possible to more effectively take measures against the in-machine temperature rise.
[0038]
In addition, since the first exhaust unit and the second exhaust unit are provided on the side surface opposite to the operation unit, a noise level to an operator of the operation unit can be reduced, and a configuration that does not cause discomfort is possible. It becomes.
[0039]
In addition, since the image forming apparatus has a detecting unit for detecting the temperature inside the apparatus, if the first opening and the second opening are controlled by the detection signal, the photosensitive member can be more reliably provided. Temperature can be prevented.
[0040]
Further, by arranging the yellow photoconductor at a position closest to (closest to) the first opening / closing opening or the second opening / closing opening of the plurality of photoconductors, the ozone product is most likely to be attached thereto. However, since a photoconductor having a color that is hardly noticeable on the image is arranged, a defect of the image is less likely to occur.
[0041]
Further, since a part of the second wall separating the fixing unit and the photosensitive member is also used as the intermediate transfer belt, the belt can be cooled, and the cooled belt can cool the photosensitive member. In addition, the configuration of the wall is simplified, the whole device can be made small, and the cost can be reduced.
[0042]
There is a third opening and closing port configured to be freely openable and closable between the first air path and the second air path, and a driving means for freely opening and closing the opening and closing means, and a control means for controlling the driving means. With this arrangement, it is possible to reduce the number of exhaust means for forcibly exhausting air, thereby reducing the noise level for the user and the cost.
[0043]
In addition, by arranging the exhaust means in the first air path described above on the side closer to the fixing in the air path, the heat from the fixing means is not transferred to the air path more efficiently without moving the heat from the fixing means into the air path. It becomes possible to exhaust.
[0044]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto unless otherwise specified. Absent.
[0045]
FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a top view thereof. Note that the image forming apparatus according to the present embodiment is an electrophotographic type and is described as a color image output apparatus arranged in series.
[0046]
The image forming apparatus includes four stations arranged in parallel (each station has the same configuration) as an image output unit, and further includes a sheet feeding unit 20, an intermediate transfer unit 132, a fixing unit 111, and a control unit (not shown). ).
[0047]
Each unit will be described in detail. The image forming section has the following configuration. Photosensitive drums 11a, 11b, 11c, and 11d as image carriers are pivotally supported at their centers, and are driven to rotate in the direction of arrows. Primary charging rollers 12a, 12b, 12c, and 12d, optical systems 60a, 60b, 60c, and 60d, and developing devices 14a, 14b, 14c, and 14d are arranged in the rotation direction of the photosensitive drums 11a to 11d so as to face the outer peripheral surfaces thereof. I have. The primary charging rollers 12a to 12d apply charges of a uniform charge amount to the surfaces of the photosensitive drums 11a to 11d. Next, the optical systems 60a to 60d expose the photosensitive drums 11a to 11d with light beams such as laser beams modulated according to the recording image signals, thereby forming electrostatic latent images thereon. Further, the electrostatic latent images are visualized by the developing devices 14a to 14d each storing developers (toners) of four colors such as yellow, cyan, magenta, and black. According to the process described above, the image formation on the photosensitive drum by each toner is sequentially performed.
[0048]
The paper feeding unit 20 includes a cassette 21a for storing paper (recording material) P as a transfer material, pickup rollers 22a and 22b for sending out the recording material P one by one, and a recording material P sent from each pickup roller. Roller pair 23 for transporting the recording material P to the registration roller, and registration rollers 25a and 25b for sending the recording material P to the secondary transfer area (secondary transfer roller 72) in accordance with the image forming timing of the image forming unit. Become.
[0049]
The intermediate transfer unit 132 will be described in detail. The intermediate transfer belt 132 is made of, for example, PET (polyethylene terephthalate) or PVdF (polyvinylidene fluoride) as the material thereof. The drive roller 32 for transmitting the drive to the intermediate transfer belt 132 and the spring (not shown) are urged. The intermediate transfer belt 132 is wound around a tension roller 33 that applies an appropriate tension to the intermediate transfer belt 132 and a driven roller 34 that faces the secondary transfer area (secondary transfer roller 72) with the belt interposed therebetween. Among these, a primary transfer plane is formed between the drive roller 32 and the tension roller 33. The drive roller 32 has a surface of a metal roller coated with rubber or the like having a thickness of several mm to prevent slippage with the belt. The drive roller 32 is driven to rotate by a pulse motor (not shown). Primary transfer rollers 104a to 104d are arranged on the back of the intermediate transfer belt 132 in a primary transfer area where the respective photosensitive drums 11a to 11d and the intermediate transfer belt 132 face each other. A secondary transfer roller 72 is arranged to face the driven roller 34, and forms a secondary transfer area by nip with the intermediate transfer belt 132. The secondary transfer roller 72 is pressed with an appropriate pressure on the intermediate transfer member.
[0050]
The fixing unit 111 includes a roller pair including a fixing roller 111a having a heat source such as a halogen heater therein and a roller 111b pressed against the roller (the roller may also have a heat source). A guide for guiding the recording material P to the pair of nip portions, an inner discharge roller 44 for guiding the recording material P discharged from the roller pair to the outside of the apparatus, and an outer discharge roller 45 are provided.
[0051]
The control unit includes a control board for controlling the operation of the mechanism in each unit, a motor drive board, a power supply, and the like.
[0052]
Next, an explanation will be given in accordance with the operation of the apparatus.
[0053]
When the image forming operation start signal is issued, first, the recording material P is sent out one by one from the cassette 21a by the pickup roller 22a. Then, the recording material P is transported by the paper feed roller pair 23 to the registration rollers 25a and 25b. At that time, the registration roller is stopped, and the leading end of the paper strikes the nip. Thereafter, the registration roller starts rotating at the timing when the image forming unit starts forming an image. The rotation timing is set so that the recording material P and the toner image primarily transferred from the image forming section onto the intermediate transfer belt just coincide with each other in the secondary transfer area (secondary transfer roller 72). I have.
[0054]
On the other hand, in the image forming section, when the image forming operation start signal is issued, a high voltage is applied to the toner image formed on the photosensitive drum 11d at the most upstream in the rotation direction of the intermediate transfer belt 132 by the above-described process. The primary transfer is performed by the primary transfer charging roller 104d on the intermediate transfer belt 132 in the primary transfer area. The primary-transferred toner image is transported to the next primary transfer area. In this case, the image formation is performed with a delay of the time during which the toner image is conveyed between the respective image forming sections, and the next toner image is transferred with the registration on the previous image. Hereinafter, the same steps are repeated, and the toner images of four colors are primarily transferred on the intermediate transfer belt 132 after all.
[0055]
Thereafter, when the recording material P enters the secondary transfer area (secondary transfer roller 72) and comes into contact with the intermediate transfer belt 132, a high voltage is applied to the secondary transfer roller 72 in synchronization with the passage timing of the recording material P. Then, the four color toner images formed on the intermediate transfer belt by the above-described process are transferred onto the surface of the recording material P. Thereafter, the recording material P is guided to the fixing roller nip by the conveyance guide. Then, the toner image is fixed on the paper surface by the heat of the roller pair 111a and 111b and the pressure of the nip. Thereafter, the paper is conveyed by the inner and outer discharge rollers 44 and 45, and the paper is discharged outside the apparatus.
[0056]
Next, the airflow configuration of the apparatus will be described.
[0057]
The fixing device 111 and the photosensitive drums 11a to 11d are partitioned by a wall 2, and an intermediate transfer belt 132 is continuous below the photosensitive drum, and separates the fixing device and the photosensitive drum together with the wall 2. It has become. Therefore, a part of the intermediate transfer belt is configured to enter the second air path.
[0058]
On the other hand, the photosensitive drum 11 and the fixing device 111 are mounted on a front side plate 81 and a rear side plate 1 which are frame structures for supporting them. The photosensitive drum 11 has a rear end supported by a rear plate and is connected to a driving device 70 disposed on the back side of the rear plate. The driving of a driving source 75 such as a motor disposed on the driving device 70 is performed. It is driven to rotate by force.
[0059]
In order to adopt such a configuration, the photosensitive drum and the developing device are spatially separated from each other by a driving device thereof and a wall (rear side plate). On the other hand, on the rear side plate, a controller for controlling the entire image forming apparatus, a high voltage unit for charging the photosensitive drum, a driver unit for driving a driving source such as various motors, and a power supply for these so-called electrical components are supplied. A power supply and the like are arranged.
[0060]
In addition, a rear cover, which serves as an exterior, is arranged outside such drive devices and electrical components. The second wall disposed between the fixing device and the photosensitive drum extends to the exterior, thereby forming a first air path extending to the fixing direction at the rear of the photosensitive drum. Since the fan 73 serving as an exhaust unit is disposed in the first air passage, an airflow is generated in the first air passage from the paper supply side to the fixing side. By realizing such an airflow, the various electric components or the driving device 70 disposed in the air passage are cooled and the temperature rise thereof can be suppressed. In addition, since the drive source 75 such as a motor disposed in the drive device is disposed on the side closest to the outside air in the drive device, cooling is performed more effectively, and the temperature rise is suppressed to a low level. By suppressing the rise in the temperature of the electrical components and the drive unit, not only the parts are not damaged due to the rise in temperature of the drive itself, but also the influence of heat on the photosensitive drum is reduced. In addition, it can be kept low.
[0061]
Further, since the exhaust unit 73 is disposed on the fixing device side in the air path, there is an effect that the inside of the apparatus is exhausted rearward without drawing the heat radiated from the fixing to the sheet feeding side.
[0062]
On the other hand, the periphery of the fixing is spatially separated from the photosensitive drum as described above, and the second air path thus formed is provided with exhaust means at the rear in the longitudinal direction thereof. By arranging the fan 74, heat generated from fixing is discharged from the front side of the image forming apparatus to the rear side. In addition, since a part of the intermediate transfer belt is formed in the first air passage, the belt is cooled by the air flow in the air passage, and the belt is in contact with the photosensitive drum at the primary transfer portion. In addition, the photosensitive drum can be cooled without disturbing the airflow around the photosensitive drum. By thus efficiently discharging the heat of the fixing device, the influence of the heat on the photosensitive drum is reduced, and the temperature rise of the photosensitive drum is suppressed. Also, since the airflow of the exhaust heat does not affect the periphery of the photosensitive drum similarly to the airflow in the first air path, the airflow of the exhaust heat does not affect the toner existing around the drum at the time of image formation. It is not a factor to cause.
[0063]
In addition, since both of the exhaust fans, which are the exhaust means, are disposed behind the image forming apparatus, the noise level for an operator located in front of the apparatus for operating the image forming apparatus can be suppressed low, and the It does not give a pleasant feeling.
[0064]
As described above, since the heat, which is a heat source applied to the photosensitive drum, is exhausted by the airflow that does not disturb the periphery of the photosensitive drum, the influence of the temperature rise on the photosensitive drum is small. However, when the ambient temperature around the image forming apparatus is high, it may be necessary to exhaust heat to the photosensitive drum. Further, ozone products generated when the photosensitive drum is charged stay around the photosensitive drum, and when the ozone product is used for a long time, the ozone product affects the surface of the photosensitive drum to cause an image defect. The air flow around the photosensitive drum for solving such a problem will be described continuously.
[0065]
A first wall (rear side plate) provided at the rear portion of the photosensitive drum is provided with a first opening / closing port 51 which can be freely opened and closed, and a second wall separating the fixing device and the photosensitive drum. Is provided with a second opening / closing opening 52 that can be freely opened and closed.
[0066]
Each of these opening / closing ports 51 and 52 can be freely opened and closed by a driving source such as a solenoid or a motor (not shown) with a part thereof as a center of rotation.
[0067]
These opening / closing ports 51 and 52 are not opened during the image forming process, and are controlled to be opened when the image forming process is completed. When the first opening / closing opening 51 or the second opening / closing opening 52 is opened, outside air enters from around the photosensitive drum through a louver provided on the apparatus feeding side, and passes through around the photosensitive drum. The air is exhausted after joining the air passage 1 or 2. On the other hand, near the photosensitive drum in the image forming apparatus, a sensor 90 serving as a detecting unit capable of detecting the temperature inside the apparatus is arranged. If the temperature of the photosensitive drum has reached a certain temperature or higher based on the temperature information from this sensor, after the image forming process has been completed, or after the image forming process has been forcibly terminated, the primary The first opening / closing opening 51 or the second opening / closing opening 52 is opened to exhaust heat around the photosensitive drum.
[0068]
Since such control is performed after the end of the image forming process, it is possible to take measures to increase the temperature when the temperature of the photosensitive drum is increased and eliminate ozone products around the photosensitive drum without causing toner to scatter inside the apparatus. It becomes possible. The position closest to these openings 1 and 2 is where the ozone products from the plurality of photosensitive drums merge and are most likely to accumulate, but the yellow photosensitive material, which is the color in which image defects are most inconspicuous on the image. By arranging the drum near the opening, even if an image defect occurs due to the influence of an ozone product, the influence as an image defect is minimized.
[0069]
The stay in which the exposure device is disposed has a function of separating the exposure devices 60a to 60d from the photosensitive drum 11 as a third wall.
[0070]
As described above, according to the image forming apparatus of the present embodiment, various electric components such as a fixing device and the like are improved while preventing the toner from scattering around the photosensitive drum to improve the optical performance of the exposure device. It is possible to efficiently suppress the temperature rise in the device due to heat radiation from the device.
[0071]
(Other embodiments)
In addition to the above embodiment, a configuration as shown in FIGS. 3 and 4 can be adopted as another embodiment of the present invention.
[0072]
The sheet is conveyed one by one from the storage section 21a in which the sheet is stored by the pickup roller 22a, and the control of the image and the sheet conveyance timing and then the conveyance to the secondary transfer position, and the configuration have already been described. This is the same as the above example. The latent images irradiated on the photosensitive drum 11 by the exposure device 60 are sequentially developed by the developing devices 14a to 14d, and are transferred onto the transfer belt 132 each time one-color development is performed. While a certain color is being developed, the other developing devices are controlled so as not to perform development by, for example, retracting from the photosensitive drum. By successively transferring the colors one by one on the intermediate transfer belt 132, a four-color full-color toner image is finally formed on the intermediate transfer belt. Meanwhile, the secondary transfer roller 72 is separated to the position shown by the broken line. The images formed on the intermediate transfer belt are collectively transferred onto the recording material P by the secondary transfer roller 72, and then conveyed to the fixing device 111. The configuration of the fixing device is the same as that of the embodiment described above. The sheet that has passed through the fixing device is discharged to the outside of the apparatus by the inner discharge roller 44 and the outer discharge roller 45 after the toner image is fixed on the recording material P by the fixing device.
[0073]
The photosensitive drum 11 is supported between a front plate 81 and a rear plate 1 which is a frame of the image forming apparatus, and its driving device is disposed on the back side of the rear plate 1 like the driving device of the developing device. Have been. An air path is formed by the rear plate and the rear exterior, in which the electric component 71 and the driving device 70 described above are arranged, and include a motor and the like in the driving device. The driving source 75 is disposed at a position farthest from the fixing device in the driving device. On the other hand, the fixing device and the photosensitive drum 11 are separated by the wall 2, and the photosensitive drum and the fixing device are spatially separated by the intermediate transfer belt 132. A fan 74, which is an exhaust unit for forcibly generating an airflow, is disposed behind the second air passage having the wall 2 as a part thereof, and the fan 74 does not affect the photosensitive drum. Exhaust heat for fixing is performed in an airflow state.
[0074]
Opening / closing ports 51 and 52 are provided for each air path, and the operation and control thereof are the same as those of the above-described embodiment.
[0075]
The first air passage arranged behind the photosensitive drum and the second air passage arranged behind the fixing are connected by a third opening / closing opening 53. The third opening / closing port 53 can be freely opened / closed with one end thereof as a rotation center, and its movement can be controlled by a solenoid, a motor (not shown), and control means for controlling them. Configuration.
[0076]
Normally, even in a state in which no image is formed, that is, in a so-called standby state, the fixing device keeps heating control of a heater provided in the roller so that the image forming operation can be started immediately. Therefore, it is necessary to continue the heat discharging operation even in the standby state. On the other hand, various electric and electrical components such as a power supply device, a controller unit, and a driving source, which can be a heat source other than the fixing, mainly generate heat during image formation, and generally have little effect during standby. For this reason, during standby, the third opening / closing port 53 is closed, the heat exhaust of the first air passage is stopped, and the fan 74 is mainly used as a heat exhaust means for fixing, so that image formation is not performed. It is possible to adopt a configuration in which the third opening / closing port 53 is opened at the start of the process, and the first air path and the second air path are exhausted by the fan 74.
[0077]
By adopting such a configuration, the size of the apparatus itself can be reduced, the cost can be reduced, and an image forming apparatus can be used, as compared with a case where exhaust means such as a fan for forcibly exhausting and exhausting heat is provided in each air path. This has the effect of lowering the noise level given to the operating operator.
[0078]
【The invention's effect】
As described above, according to the present invention, it is possible to suppress the temperature rise in the apparatus and prevent the toner from scattering around the photoconductor. Further, it is possible to eliminate ozone products generated around the photoconductor.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a main internal structure of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a top view showing the image forming apparatus according to the embodiment;
FIG. 3 is a side sectional view showing a main internal structure of an image forming apparatus according to another embodiment of the present invention.
FIG. 4 is a top view illustrating an image forming apparatus according to another embodiment.
FIG. 5 is a side sectional view showing a main internal structure of an example of a conventional image forming apparatus.
[Explanation of symbols]
1 First wall
2 Second wall
3 Third wall
11 Photosensitive drum
14 Developing device
51 1st opening and closing opening
52 Second door
53 Third door
60 Exposure equipment
71 Electrical part
72 Secondary transfer roller
73, 74 fans
70 Drive
75 Drive source
90 Temperature measurement sensor
111 fixing device
132 Intermediate transfer belt

Claims (13)

A photoreceptor,
Exposure means for performing exposure on the photoconductor,
Developing means for developing the latent image on the exposed photoconductor as a toner image,
Transfer means for transferring the developed image onto a transfer material,
Fixing means for melting the toner image on the transfer material and fixing it to the transfer material;
In an image forming apparatus having an image forming process on a transfer material having
As a first air path, a driving unit that drives the photoconductor or the developing unit and a photoconductor are formed to form an air path in a direction orthogonal to the longitudinal direction of the photoconductor and toward the fixing unit. A first wall separating them,
A second wall separating the fixing unit and the photoreceptor so as to form a second air passage extending in a longitudinal direction of the fixing unit;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
At least one opening and closing port that is opened and closed to communicate and block between the first air path and the second air path;
Control means for controlling the opening and closing of the opening,
An image forming apparatus comprising: The image forming apparatus according to claim 1, further comprising a third wall separating the exposure unit and the photoconductor. The image forming apparatus according to claim 3,
A first opening and closing opening configured to be openable and closable on the first wall;
Control means for controlling opening and closing of the first opening and closing opening;
An image forming apparatus comprising: The image forming apparatus according to claim 1, wherein
A second opening and closing port configured to be openable and closable on the second wall;
Control means for controlling the opening and closing of the second opening and closing opening;
An image forming apparatus comprising: The image forming apparatus according to any one of claims 1 to 5,
A driving unit for driving the photoconductor or the developing unit is disposed in the first air passage, and a motor as a component of the driving unit is compared with other components of the driving unit. An image forming apparatus which is arranged at the most upstream side along the air path and at a position farthest from the fixing unit. The image forming apparatus according to any one of claims 1 to 6,
A power supply for supplying power to the image forming apparatus;
An electrical unit including a control controller board for controlling the image forming apparatus;
With and
An image forming apparatus, wherein at least one of the power supply unit and the electrical unit is disposed in the first air passage or the second air passage. The image forming apparatus according to any one of claims 1 to 7,
First exhaust means for forcibly generating an airflow in the first air passage and discharging air in the image forming apparatus to the outside;
Second exhaust means for forcibly generating an airflow in the second air passage and discharging air in the image forming apparatus to the outside;
An image forming apparatus having a side surface of the image forming apparatus. The image forming apparatus according to claim 8,
The image forming apparatus according to claim 1, wherein the first exhaust unit is disposed immediately adjacent to the fixing device. The image forming apparatus according to claim 9,
An operation unit for operating the image forming apparatus from outside is arranged on one side of the apparatus, and the first exhaust unit and the second exhaust unit are arranged on the opposite side of the image forming apparatus. Image forming apparatus. The image forming apparatus according to any one of claims 1 to 10,
An image forming apparatus comprising: a detecting unit configured to detect a temperature in the image forming apparatus. The image forming apparatus according to claim 2,
A plurality of photoconductors including at least a photoconductor carrying a yellow-based image, and
An image forming apparatus, wherein a photoreceptor carrying the yellow-based image is disposed immediately adjacent to the opening / closing opening. The image forming apparatus according to claim 1,
Comprising a plurality of photoconductors arranged in series, and
The transfer means,
An endless intermediate transfer belt that faces the plurality of photoconductors arranged in series, performs primary transfer of the toner image on the photoconductor, and performs secondary transfer on a transfer material.
Further, an image forming apparatus is characterized in that a part of the intermediate transfer belt forms a part of the second wall.

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