Patent Grant
11822284
The present invention relates to an image forming apparatus such as a printer, a copier, a facsimile, or a multifunction peripheral.
In an image forming apparatus, a toner image is formed on an image bearing member such as a photosensitive drum or an intermediate transfer belt, the toner image is transferred from the image bearing member to a recording material, and then heat and pressure are applied by a fixing unit to fix the toner image on the recording material. In such an image forming apparatus that forms an image on a recording material using toner, a developing unit that develops an electrostatic latent image of the image bearing member using the toner is provided. The developing unit accommodates the toner therein, and circulates and conveys the toner while stirring the toner by a conveying screw in the developing unit. Therefore, the developing unit generates heat in response to a toner stirring operation. As described above, a plurality of units that generates heat, such as the fixing unit and the developing unit, are provided inside the image forming apparatus.
Therefore, conventionally, a configuration has been proposed in which a plurality of cooling targets such as a fixing unit and a developing unit are cooled by outside air taken in from an intake port by an intake fan (Japanese Patent Application Laid-Open No. 2010-32780). In the device described in Japanese Patent Application Laid-Open No. 2010-32780, in order to efficiently blow air to each of the plurality of cooling targets, a plurality of fans is provided, and ducts connecting the fans from the intake ports are provided for the number of fans. In this case, each of the plurality of cooling targets can be efficiently cooled.
Meanwhile, an image forming apparatus that forms an image on a recording material using toners of a plurality of colors includes a plurality of image forming units (also referred to as image forming stations) that form toner images of respective colors on a photosensitive drum for each color. In the case of including a plurality of image forming units, it is necessary to cool each cooling target included in each image forming unit. In this case, as in the device described in Japanese Patent Application Laid-Open No. 2010-32780, when the plurality of ducts is provided for connecting the fan from the intake port for each of a plurality of cooling targets, a sufficient air blowing amount to each cooling target can be secured, but an area occupied by the ducts increases in the image forming apparatus. Therefore, conventionally, in order to secure a space for individually disposing the fan and the duct for each of the plurality of units, it is necessary to increase the size of the device. However, this goes against a recent demand for miniaturization of the device, and thus it is difficult to adopt the device.
In view of the above problems, there is need for providing an image forming apparatus capable of suppressing an increase in size of the apparatus and guiding outside air taken in by an intake fan with a sufficient air blowing amount secured when the outside air is guided toward a plurality of units via ducts.
According to a first aspect of the present invention, an image forming apparatus configured to form an image on a recording material includes a first image forming unit among a plurality of image forming units, the first image forming unit having a first photosensitive member, a first charging unit configured to charge the first photosensitive member by corona discharge, and a first developing unit configured to develop an electrostatic latent image formed on the first photosensitive member using toner, a second image forming unit among the plurality of image forming units, the second image forming unit having a second photosensitive member, a second charging unit configured to charge the second photosensitive member by corona discharge, and a second developing unit configured to develop an electrostatic latent image formed on the second photosensitive member using toner, and an intake unit including an intake duct provided at one side relative to the first and the second image forming units in an arrangement direction of the plurality of image forming units and configured to take in air outside the image forming apparatus from an intake port, a first fan configured to take in air from a first communication port formed in a first side surface portion of the intake duct, and a second fan configured to take in air from a second communication port formed in a second side surface portion facing the first side surface portion of the intake duct. The intake unit is configured to branch air in the intake duct to the air taken in from the first communication port by the first fan and the air taken in from the second communication port by the second fan, and blow the air to each of the first image forming unit and the second image forming unit.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Image Forming System
A schematic configuration of an image forming system including an image forming apparatus of the present embodiment will be described with reference to
Image Forming Apparatus
The image forming apparatus 100 is an electrophotographic tandem full-color printer, and includes a first casing 101a and a second casing 101b. In the first casing 101a, various devices such as an image forming unit 700 that realizes a process of conveying the recording material S and transferring the toner image, various members, and the like are disposed.
Meanwhile, in the second casing 101b, various devices such as a fixing unit 800 that realizes a process of conveying the recording material S and fixing the toner image, various members, and the like are disposed. In addition, the second casing 101b is provided with an operation unit 200 having a display unit capable of displaying various types of information on the front side, a key capable of inputting various types of information according to a user operation, and the like. An electric unit (not illustrated) having a power supply board may be disposed on the back side of the first casing 101a and the second casing 101b. In the present specification, in order to operate the image forming apparatus 100 by the user, a side on which a user stands when operating the operation unit 200 is referred to as a “front surface”, and an opposite side thereof is referred to as a “back surface”. In addition, a side surface on a left side when viewed from the front is referred to as a “left surface”, and a side surface on the right side when viewed from the front is referred to as a “right surface”.
The image forming apparatus 100 includes image forming portions Pa, Pb, Pc, and Pd that form yellow, magenta, cyan, and black images, respectively. The image forming apparatus 100 forms a toner image on the recording material S according to an image signal received from an external device (not illustrated) such as the document reading apparatus 190 or a personal computer that reads an image signal from a document.
In the case of the present embodiment, the image forming portions Pa to Pd, primary transfer rollers 24a to 24d, an intermediate transfer belt 130, plurality of rollers 13 to 15, and a secondary transfer outer roller 11 constitute an image forming unit 700 that forms a toner image on the recording material S. Examples of the recording material S include paper such as plain paper, thick paper, rough paper, uneven paper, and coated paper, a plastic film, cloth, and the like.
As illustrated in
On the lower side of the image forming apparatus 100, a plurality of (here, two) cassettes 10 in which recording materials S are accommodated are arranged. The recording materials S having different sizes and thicknesses are accommodated in the cassettes 10, and the recording material S is selectively conveyed from one of the cassettes 10. The recording material S is conveyed from the cassette 10 toward a registration roller 12 through a conveying path by a conveying roller 16. Thereafter, the registration roller 12 rotates in synchronization with the toner image formed on the intermediate transfer belt 130, whereby the recording material S is conveyed toward the secondary transfer portion T2. Note that the recording material S is not limited to the recording material S stored in the cassette 10, and the recording material S placed on a manual feed unit (not illustrated) may be conveyed.
The image forming portions Pa, Pb, Pc, and Pd have substantially the same configuration except that developed colors of the toner images are different. Therefore, here, the yellow image forming portion Pa will be described as a representative, and description of the other image forming portions Pb, Pc, and Pd will be omitted.
In the image forming portion Pa, a cylindrical photosensitive drum 3a is disposed as a photosensitive member. The photosensitive drum 3a is rotationally driven by a motor (not illustrated). A charging unit 2a, an exposing unit La, a developing unit 1a, the primary transfer roller 24a, and a drum cleaning unit 4a are disposed around the photosensitive drum 3a. In the present embodiment, the image forming portion Pa is an example of a first image forming unit which is one of a plurality of image forming units. The image forming portion Pa includes the photosensitive drum 3a which is an example of a first photosensitive member, the charging unit 2a which is an example of a first charging unit that charges the photosensitive drum 3a by corona discharge, and the developing unit 1a which is an example of a first developing unit that develops an electrostatic latent image formed on the photosensitive drum 3a using toner. In the present embodiment, the image forming portion Pb is an example of a third image forming unit which is one of the plurality of image forming units. The image forming portion Pb includes a photosensitive drum 3b that is an example of the third photosensitive member, a charging unit 2b that is an example of a third charging unit that charges the photosensitive drum 3b by corona discharge, and a developing unit 1b that is an example of a third developing unit that develops an electrostatic latent image formed on the photosensitive drum 3b using toner. In the present embodiment, the image forming portion Pc is an example of a fourth image forming unit which is one of the plurality of image forming units. The image forming portion Pc includes a photosensitive drum 3c which is an example of a fourth photosensitive member, a charging unit 2c which is an example of a fourth charging unit that charges the photosensitive drum 3c by corona discharge, and a developing unit 1c which is an example of a fourth developing unit that develops an electrostatic latent image formed on the photosensitive drum 3c using toner. In the present embodiment, the image forming portion Pd is an example of a second image forming unit which is one of the plurality of image forming units. The image forming portion Pd includes a photosensitive drum 3d which is an example of a second photosensitive member, a charging unit 2d which is an example of a second charging unit that charges the photosensitive drum 3d by corona discharge, and a developing unit 1d which is an example of a second developing unit that develops an electrostatic latent image formed on the photosensitive drum 3d using toner.
For example, a process of forming a full-color image by the image forming apparatus 100 will be described. First, when the image forming operation is started, the surface of the rotating photosensitive drum 3a is uniformly charged by the charging unit 2a. The charging unit 2a is, for example, a corona charger that irradiates charged particles associated with corona discharge to charge the surface of the photosensitive drum 3a to a uniform potential. Next, the photosensitive drum 3a is scanned and exposed by a laser beam corresponding to an image signal emitted from the exposing unit La. As a result, an electrostatic latent image corresponding to the image signal is formed on the surface of the photosensitive drum 3a. The electrostatic latent image formed on the photosensitive drum 3a is developed into a toner image that is a visible image by a developer containing toner and a carrier stored in the developing unit 1a. In other words, the toner image is developed on the photosensitive drum 3a by the toner supplied by the developing unit 1a. In the developing units 1a to 1d, the developer is circularly conveyed while being stirred by a conveying screw (not illustrated).
The toner image formed on the photosensitive drum 3a is primarily transferred to the intermediate transfer belt 130 at a primary transfer portion T1 configured between the primary transfer roller 24a and the photosensitive drum 3a, the primary transfer roller 24a being disposed with the intermediate transfer belt 130 interposed therebetween. At this time, a primary transfer voltage is applied to the primary transfer roller 24a. The toner remaining on the surface of the photosensitive drum 3a after the primary transfer is removed by the drum cleaning unit 4a.
Such an operation is sequentially performed in the yellow, magenta, cyan, and black image forming portions Pa to Pd, and toner images of four colors are superimposed on the intermediate transfer belt 130. Thereafter, the recording material S accommodated in the cassette 10 is conveyed to the secondary transfer portion T2 in accordance with the formation timing of the toner image. Then, by applying a secondary transfer voltage to the secondary transfer outer roller 11, the full-color toner images formed on the intermediate transfer belt 130 are secondarily transferred collectively to the recording material S. The toner remaining on the intermediate transfer belt 130 after the secondary transfer is removed by a belt cleaning unit (not illustrated).
In the present embodiment, the photosensitive drum 3a corresponds to the first photosensitive member, and the photosensitive drums 3b, 3c, and 3d correspond to the second photosensitive members. The developing unit 1a corresponds to a first developing unit, and the developing units 1b, 1c, and 1d correspond to second developing units.
The recording material S to which the toner image has been transferred is conveyed to the fixing unit 800. The fixing unit 800 fixes the toner image on the recording material S by applying heat and pressure to the recording material S to which the toner image has been transferred. In the case of the present embodiment, it is possible to selectively apply heat and pressure to the recording material S by a first fixing device 81 and then further apply heat and pressure by a second fixing device 91. In the fixing unit 800, whether the recording material S is conveyed toward the second fixing device 91 after passing through the first fixing device 81 or is conveyed while avoiding the second fixing device 91 after passing through the first fixing device 81 is switched by a fixing switching member 95.
The second fixing device 91 is disposed on the downstream of the first fixing device 81 in the conveyance direction of the recording material S. The second fixing device 91 is selectively used for the purpose of further adding gloss to the toner image on the recording material S fixed by the first fixing device 81. For example, in a case where the recording material S is coated paper such as glossy paper or synthetic paper, the recording material S having passed through the first fixing device 81 is conveyed along a fixing route 30a so that fixing is performed by both the first fixing device 81 and the second fixing device 91. Meanwhile, in a case where the recording material S is non-coated paper such as plain paper, the recording material S having passed through the first fixing device 81 is conveyed along a fixing-by-pass route 30b avoiding the second fixing device 91 so that the fixing is not performed in the second fixing device 91 while the fixing is performed in the first fixing device 81.
Since the first fixing device 81 and the second fixing device 91 may have the same configuration, the first fixing device 81 will be described as an example. The first fixing device 81 includes a fixing roller 82 (or a fixing belt) that is rotatable in contact with a surface of the recording material S on which the toner image is fixed, and a pressure belt 83 (or a pressure roller) that is pressed against the fixing roller 82 to form a fixing nip portion. At least one of the fixing roller 82 and the pressure belt 83 is heated by a heater (not illustrated). The first fixing device 81 applies heat and pressure to the recording material S at the time of nipping and conveying the recording material S on which the toner image is formed in the fixing nip portion formed by the fixing roller 82 and the pressure belt 83 to fix the toner image on the recording material S.
In the present embodiment, the image forming apparatus 100 can perform duplex printing. In the case of single-sided printing, the recording material S on which the toner image is fixed is conveyed to a discharge conveyance path 150 and discharged to the outside of the image forming apparatus 100. In the case of duplex printing, the recording material S on which the toner image is fixed is conveyed to a duplex reverse conveyance path 600. The duplex reverse conveyance path 600 is formed across the first casing 101a and the second casing 101b. In the duplex reverse conveyance path 600, the recording material S is reversed by the switchback operation, and the front surface and the back surface of the recording material S are exchanged. The reversed recording material S is conveyed toward the registration roller 12, and is conveyed to the secondary transfer portion T2 by the registration roller 12 in a state where the back surface side that is not printed faces the intermediate transfer belt 130 side. In the secondary transfer portion T2, the full-color toner images formed on the intermediate transfer belt 130 are secondarily transferred collectively to the recording material S (back surface side). Thereafter, the toner image is fixed by the fixing unit 800, and the recording material S is discharged to the outside of the image forming apparatus 100 in a state where a surface (image forming surface) on which an image has been formed immediately before faces upward. The above-described switching between the discharge conveyance path 150 and the duplex reverse conveyance path 600 is performed by a conveyance switching member 160. In the present embodiment, two fixing devices are provided as the fixing unit 800, but only one fixing device may be provided. In addition, a cooling unit that cools the recording material S on which the toner image is fixed by the fixing unit 800 may be provided in the second casing 101b.
The finisher device 300 is connected to the image forming apparatus 100 so as to be able to transfer the recording material S, and the recording material S discharged from the image forming apparatus 100 is conveyed to the finisher device 300. The recording material S conveyed to the finisher device 300 is subjected to post-process processing such as punching processing of forming a hole in the recording material S by the finisher device 300 or stapling processing of bundling and needle-closing a plurality of recording materials S. In the finisher device 300, the holed recording material S is separately discharged to an upper sheet discharge tray 301, and the bundle of the needle-closed recording materials S is separately discharged to a lower sheet discharge tray 302.
Hereinafter, an airflow configuration of outside air in the image forming apparatus 100 will be described with reference to
As illustrated in
As illustrated in
As illustrated in
In the charging units 2a to 2d, the surfaces of the photosensitive drums 3a to 3d are charged by ionizing air by corona discharge to generate ions. In addition, the charging units 2a to 2d generate not only ions but also ozone during the corona discharge. However, since the ozone easily corrodes, for example, a stainless steel grid (not illustrated) or the like included in the charging units 2a to 2d, ozone needs to be recovered. Therefore, although in the vicinity of the charging units 2a to 2d, a primary intake duct (not illustrated) that blows outside air to the charging units 2a to 2d and a primary exhaust duct (not illustrated) that exhausts air to the outside of the image forming apparatus 100 via the ozone recovery filter are disposed in order to send ozone to an ozone recovery filter (not illustrated) by outside air for recovery.
Left Intake Unit
The left intake unit 124 will be described with reference to
As illustrated in
As illustrated in
Meanwhile, as illustrated in
Then, as illustrated in
In the present embodiment, the developing intake fans 180a to 180d and the charging intake fans 177a and 177b, which are sirocco fans, are disposed on the left surface portion 1741 and the right surface portion 1742 of the left main body duct 174 with the intake side facing the left main body duct 174. As described above, in the left main body duct 174, the developing intake fan 180a and the charging intake fans 177a and 177b are disposed on the left surface portion 1741, and the developing intake fans 180b, 180c, and 180d are disposed on the right surface portion 1742. As described above, by using the ducts from the intake port 171a to the developing intake fans 180a to 180d and the charging intake fans 177a and 177b as a common duct, it is possible to reduce the area occupied by the ducts as compared with a configuration in which the ducts connecting the fan and the intake port are provided for the number of the plurality of fans, and it is possible to suppress an increase in size of the image forming apparatus itself due to an increase in size of the duct. In addition, since the arrangement of the ducts can be simplified, the degree of freedom in design can be improved without affecting the arrangement of other units.
When the developing intake fans 180a to 180d and the charging intake fans 177a and 177b are disposed in the left main body duct 174, the inventors have studied arrangement positions where the intake fans are not easily affected by intake air by other intake fans by air flow simulation.
As illustrated in
As described above, the communication ports 1741a to 1741c and 1742a to 1742c in the left main body duct 174 are disposed at positions not facing each other, and thus, occurrence of drift in the left main body duct 174 can be suppressed. In the present embodiment, a distance between the left surface portion 1741 and the right surface portion 1742 of the left main body duct 174 is set to 20 mm or more and 50 mm or less. By setting the distance between the left surface portion 1741 and the right surface portion 1742 to 20 mm or more in this manner, it is possible to suppress the occurrence of drift in the air flow generated inside the left main body duct 174 when air is taken in from the communication ports 1741a to 1741c and the communication ports 1742a to 1742c.
For example, when the distance between the left surface portion 1741 and the right surface portion 1742 is smaller than 20 mm, an air flow generated by being taken in by the developing intake fans 180a to 180d and the charging intake fans 177a and 177b hits the left surface portion 1741 and the right surface portion 1742, and thus, a drift occurs. When the drift of air flows occurs, a loss of an air volume when air flowing into the left main body duct 174 from the intake port 171a is discharged from the communication ports 1741a to 1741c and the communication ports 1742a to 1742c becomes large.
Therefore, in the present embodiment, the distance between the left surface portion 1741 and the right surface portion 1742 of the left main body duct 174 is set to 20 mm or more, thereby suppressing the occurrence of drift inside the left main body duct 174. As a result, a loss when the air flowing into the left main body duct 174 from the intake port 171a is discharged from the communication ports 1741a to 1741c and the communication ports 1742a to 1742c can be suppressed. Therefore, a sufficient air blowing amount can be secured for the plurality of units.
When the distance between the left surface portion 1741 and the right surface portion 1742 is larger than 50 mm, drift is less likely to occur in the left main body duct 174. However, the outer shape of the left main body duct 174 becomes large, and the size of the image forming apparatus itself may be increased in order to accommodate a duct having a large outer shape. Therefore, in the present embodiment, the distance between the left surface portion 1741 and the right surface portion 1742 is set to 40 mm in consideration of the influence of the intake air of each intake fan. In this case, no drift occurs in the left main body duct 174, and an increase in pressure loss can be suppressed.
Right Intake Unit
Next, the right intake unit 126 will be described with reference to
As illustrated in
Then, as illustrated in
Note that the air flow configuration of the developing units 1a to 1d and the air flow configuration of the charging units 2a to 2d are not limited to the above-described configurations. For example, the developing intake fans 180a to 180d may be disposed in the right surface portion 1742 of the left intake unit 124, and the charging intake fans 177a and 177b may be disposed in the left surface portion 1741. That is, the number of intake fans disposed on the left surface portion 1741 and the right surface portion 1742 of the left intake unit 124 may not be the same.
Further, for example, one charging intake fan 177a and two developing intake fans 180a and 180b may be disposed on the left surface portion 1741, and three charging intake fans 177b, 177c, and 177d may be disposed on the right surface portion 1742. At this time, the developing intake fans 180c and 180d are disposed in the right intake unit 126. In this case, the charging unit 2a corresponds to a first charging unit, and the charging units 2b, 2c, and 2d correspond to a second charging unit.
Inner Cover Unit
The inner cover unit 125 will be described with reference to
Each of the flexible tubes 183a to 183d and 222a to 222d is a bellows-shaped tubular member of which an inside is formed in a hollow tubular shape using, for example, a resin such as PA6 (polyamide) or a metal, and a large number of protrusions are continuously formed at predetermined intervals on the outer peripheral surface, and is bendable. When the flexible tubes 183a to 183d and 222a to 222d are curved, the curvature is limited by the protrusion inside the curve (compression side) and it is difficult to bend the flexible tubes. Therefore, even when the flexible tubes 183a to 183d and 222a to 222d are curved, the size of the cross-sectional area is maintained as compared with that before the curvature, and the outside air can be guided without changing the air volume per unit time.
With the operations of the developing intake fans 180a to 180d, the outside air taken in from the intake port 171a passes through the left main body duct 174, the developing ducts 181a to 181d, and the flexible tubes 183a to 183d and flows toward the developing units 1a to 1d. Further, with the operation of the charging intake fans 177a and 177b, the outside air taken in from the intake port 171a passes through the left main body duct 174, the charging ducts 178a and 178b, and the flexible tubes 222a and 222b and flows toward the charging units 2a and 2b. Further, with the operation of the charging intake fans 177c and 177d, the outside air taken in from the intake port 172a passes through the right main body duct 176, the charging ducts 178c and 178d, and the flexible tubes 222c and 222d and flows toward the charging units 2c and 2d.
In the present embodiment, on the inner surface side of the inner cover unit 125, for example, the flexible tubes 183a to 183d can be appropriately curved and provided in gaps avoiding the flexible tubes 222a to 222d and the like that guide outside air to the charging units 2a to 2d. That is, the use of the flexible tubes 183a to 183d and 222a to 222d increases the degree of freedom of duct arrangement in a limited space. Note that the arrangement of the flexible tubes 183a to 183d and 222a to 222d illustrated here is an example, and the arrangement is not limited thereto.
As described above, in the present embodiment, in the left intake unit 124, the developing intake fan 180a and the charging intake fans 177a and 177b are disposed on the left surface portion of the left main body duct 174. Meanwhile, the developing intake fans 180b, 180c, and 180d are disposed on the right surface portion 1742 of the left main body duct 174. In the left intake unit 124, the outside air taken in from the intake port 171a according to the operations of the developing intake fans 180a to 180d and the charging intake fans 177a and 177b is branched into the communication ports 1741a to 1741c and the communication ports 1742a to 1742c and blown to the developing units 1a to 1d and the charging units 2a and 2b. Accordingly, when the outside air taken in by the intake fan is guided toward the plurality of units via the duct, it is possible to suppress an increase in size of the apparatus and to realize a simple configuration to guide the outside air with a sufficient air blowing amount secured.
In the embodiment described above, the sirocco fan is used as the intake fan as an example, but the present invention is not limited to this. An axial fan may be used as the intake fan.
As illustrated in
In the above-described embodiment, the case where outside air is blown to the developing units 1a to 1d and the charging units 2a to 2d has been described as an example, but the present invention is not limited thereto. For example, the above-described embodiment may also be applied to a case where a conveyance member that conveys the recording material S after passing through the first fixing device 81 and the second fixing device 91 (see
Note that, in the above-described embodiment, the electrophotographic image forming apparatus 100 is described as an example, but the present invention is not limited thereto. For example, the above-described embodiments may be applied to a thermal drying type image forming apparatus such as an inkjet printer or a sublimation type printer.
According to the present invention, when the outside air taken in by the intake fan is guided toward the plurality of units via the duct, it is possible to suppress an increase in size of the device and to realize a simple configuration to guide the outside air with a sufficient air blowing amount secured.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2021-100083, filed Jun. 16, 2021, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
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| 2021-100083 | Jun 2021 | JP | national |
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| Number | Date | Country |
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| 2010-032780 | Feb 2010 | JP |
| Number | Date | Country | |
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| 20220404763 A1 | Dec 2022 | US |
