This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2012-245372 filed Nov. 7, 2012.
The present invention relates to image forming apparatuses.
According to an aspect of the invention, there is provided an image forming apparatus including a housing; an image forming section that is provided within the housing and forms an image onto a recording medium; an output section that outputs the recording medium, having the image formed thereon by the image forming section, outward from the housing; a loading section on which the recording medium output from the output section is loaded and that is provided with an air hole; and a cooling unit that allows air to flow between an interior of the housing and the loading section via the air hole so as to cool a surface, which faces the loading section, of the recording medium loaded on the loading section.
Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:
Exemplary embodiments of the present invention will be described below with reference to the drawings.
An image forming apparatus 1 shown in
The image reader 2 includes an image reading unit 5 and a supporter 6 that supports the image reading unit 5. The image reading unit 5 is attached above the image forming unit 3 via the supporter 6.
The operable section 4 is to be operated by an operator for inputting a copy start command or information related to the number of copies, and is attached to an edge of the image reading unit 5. The operable section 4 includes a display screen 41 that displays setting contents and operation contents.
A cover 51 is provided at an upper portion of the image reading unit 5. The cover 51 is rotatably attached to a rear edge of the image reading unit 5 via a hinge 52 so that the cover 51 is openable and closable relative to the image reading unit 5. Platen glass 53 (see
The image forming unit 3 is configured to form an image onto a sheet and achieves a copying function by forming an image corresponding to a document image read by the image reading unit 5 onto a sheet. Sheet trays 31 that accommodate sheets onto which images are to be formed are provided at a lower portion of the image forming unit 3. An output tray 32 onto which a sheet having an image formed thereon and output by a pair of output rollers 333 is loaded is provided at an upper portion of the image forming unit 3. The image forming unit 3 forms an image onto a sheet accommodated in one of the sheet trays 31 by electrophotography and outputs the sheet onto the output tray 32. This will be described in detail later. The image forming unit 3 corresponds to an example of an image forming section according to an exemplary embodiment of the present invention. The image reading unit 5 is disposed above the image forming unit 3 with a gap therebetween through which a sheet loaded on the output tray 32 is retrievable by an operator.
In the image forming apparatus 1 having the above-described configuration, for example, when an operator opens the cover 51 at the upper portion of the image reading unit 5, places a document sheet on the platen glass 53 (see
First, the schematic configuration of the image reading unit 5 in the image forming apparatus 1 will be described.
In
Next, the schematic configuration of the image forming unit 3 in the image forming apparatus 1 will be described.
The image forming unit 3 shown in
The image forming unit 3 includes electrophotographic multilayer image bearing members 361K, 361C, 361M, and 361Y that rotate in directions indicated by an arrow Bk, an arrow Bc, an arrow Bm, and an arrow By, respectively. The image bearing members 361K, 361C, 361M, and 361Y are respectively surrounded by roller-shaped charging members 365K, 365C, 365M, and 365Y, light-emitting-diode print heads (LPHs) 37K, 37C, 37M, and 37Y, and developing devices 364K, 364C, 364M, and 364Y. Specifically, each charging member electrostatically charges the corresponding image bearing member while being in contact with the image bearing member and being rotated by the rotation of the image bearing member. The LPHs 37K, 37C, 37M, and 37Y irradiate the respective electrostatically-charged image bearing members 361K, 361C, 361M, and 361Y with exposure light beams based on image signals, which are emitted by multiple arranged light emitting diodes (LEDs), so as to form black (K), cyan (C), magenta (M), and yellow (Y) electrostatic latent images having potentials different from the ambient potential. Each developing device develops the electrostatic latent image on the corresponding image bearing member by electrostatically adhering an electrostatically-charged toner of the corresponding color thereto so as to form a toner image. The four developing devices 364K, 364C, 364M, and 364Y are supplied with toners of the respective colors from four toner cartridges 362K, 362C, 362M, and 362Y by mechanisms (not shown). Furthermore, the image forming unit 3 also includes an intermediate transfer belt 35 onto which the toner images of the respective colors formed on the image bearing members are transferred (first-transferred) and that transports the first-transfer toner images, cleaning devices 363K, 363C, 363M, and 363Y that remove residual toner from the image bearing members by using cleaning blades, first-transfer rollers 350K, 350C, 350M, and 350Y where the toner images of the respective colors are first-transferred onto the intermediate transfer belt 35, and a pair of second-transfer rollers 39 where the first-transfer toner images on the intermediate transfer belt 35 are second-transferred onto a sheet. The intermediate transfer belt 35 receives a driving force from a driving roller 35a and rotates in a direction indicated by an arrow A while being extended between the second-transfer roller 39b and the driving roller 35a. The image forming unit 3 also includes a fixing device 310 that fixes the second-transfer toner image, which has been transferred on the sheet but not fixed thereon yet, onto the sheet. The fixing device 310 includes a fixing roller 311 having a heating mechanism 311a, and a pressing roller 312 that is disposed facing the fixing roller 311 and that applies pressure onto the sheet. Furthermore, the image forming unit 3 includes a controller 34 that controls the components, including the LPHs 37K, 37C, 37M, and 37Y, in the image forming unit 3. An image signal that has been processed by the processing circuit 545a of the signal processing section 545 is input to the controller 34. For example, the controller 34 processes the input image signal, converts the image signal into an image signal based on which each LPH for the corresponding color forms an electrostatic latent image corresponding to an image expressed by the image signal, and sends the converted image signal to the LPH so as to make the LPH form the electrostatic latent image. Furthermore, the image forming unit 3 also includes the sheet trays 31 that accommodate sheets onto which images are to be formed, the pair of output rollers 333 that output a sheet having an image formed thereon, and the output tray 32 onto which the sheet output by the pair of output rollers 333 is loaded. The pair of output rollers 333 correspond to an example of an output section according to an exemplary embodiment of the present invention. The output tray 32 corresponds to an example of a loading section according to an exemplary embodiment of the present invention.
Next, an image forming operation performed in the image forming unit 3 will be described.
The four image bearing members 361K, 361C, 361M, and 361Y are electrostatically charged by the charging members 365K, 365C, 365M, and 365Y, respectively, and are irradiated with exposure light beams based on image signals radiated from the LEDs of the LPHs 37K, 37C, 37M, and 37Y, respectively, whereby electrostatic latent images are formed on the image bearing members 361K, 361C, 361M, and 361Y. The developing devices 364K, 364C, 364M, and 364Y develop the formed electrostatic latent images by using developers containing toners of the respective colors, thereby forming toner images of the respective colors. At the first-transfer rollers 350K, 350C, 350M, and 350Y corresponding to the respective colors, the toner images of the respective colors formed in this manner are sequentially transferred (first-transferred) and superposed onto the intermediate transfer belt 35 in the following order: yellow (Y), magenta (M), cyan (C), and black (K). As a result, a multicolor first-transfer toner image is formed. Then, the multicolor first-transfer toner image is transported to the pair of second-transfer rollers 39 by the intermediate transfer belt 35. In concert with the formation of the multicolor first-transfer toner image, a sheet is fed from one of the sheet trays 31 and is transported to a pair of first transport rollers 331, and moreover, the orientation of the sheet is adjusted by a pair of registration rollers 38. Subsequently, the pair of second-transfer rollers 39 transfer (second-transfer) the aforementioned multicolor first-transfer toner image onto the transported sheet. Then, the fixing device 310 fixes the second-transfer toner image onto the sheet. More specifically, the sheet is transported between the fixing roller 311 and the pressing roller 312 that face each other in the fixing device 310. The toners constituting the second-transfer toner image, which is formed on the sheet but not fixed thereon yet, are fused by the heating mechanism 311a of the fixing roller 311, whereby a fixed image formed of a fixed toner image is formed on the sheet. In this case, a sheet transport path is indicated by an upward dotted arrow in
After the second-transfer toner image is fixed onto the sheet by the fixing device 310, the sheet travels through a pair of second transport rollers 332 and the pair of output rollers 333 and is output onto the output tray 32, as indicated by a rightward dotted arrow in
The above description relates to the image forming operation performed in the image forming unit 3.
Because the sheet output by the pair of output rollers 333 has been heated by the heating mechanism 311a when traveling through the fixing device 310, the sheet carries heat. Therefore, when the image forming operation is performed consecutively on multiple sheets, the sheets are loaded onto the output tray 32 in a state where the heat-carrying sheets are closely in contact with each other. This may sometimes result in the occurrence of so-called sheet blocking in which the sheets become attached to each other due to re-fusing of the toner on the sheets caused by the heat.
In view of this, a countermeasure for preventing the occurrence of sheet blocking is provided in the image forming apparatus 1 according to the first exemplary embodiment.
The following description with reference to
The output tray 32 provided in the image forming unit 3 of the image forming apparatus 1 has a loading surface 321 provided with a protrusion 322 thereon. The protrusion 322 has protruding side portions 3221 provided with air holes 3221a. The loading surface 321 also has recesses 321a that are recessed downward at positions where air blown out from the air holes 3221a strikes. The protrusion 322 may be attachable to and detachable from the loading surface 321, or may be integrated with the loading surface 321.
As shown in
Referring back to
The image forming unit 3 is provided with an air blower 323 at the underside of the protrusion 322, which is a dead space. The air blower 323 is constituted of a direct-current (DC) motor and a fan. The fan is rotated by receiving a driving force from the motor and sends air toward the underside of the protrusion 322 so that the air is blown out from the air holes 3221a. The air blower 323 is of an airflow adjustable type. The air blower 323 corresponds to an example of a cooling unit according to an exemplary embodiment of the present invention.
Furthermore, the image forming unit 3 includes a temperature sensor 324 that measures the ambient temperature.
The image forming unit 3 also includes a counter 325 that counts the number of sheets output from the pair of output rollers 333.
The controller 34 provided in the image forming unit 3 controls the operation of the air blower 323. More specifically, since sheet blocking tends to occur more frequently as the number of sheets loaded on the output tray 32 increases, the controller 34 actuates the air blower 323 when the number of sheets counted by the counter 325 is 100 or more. Moreover, since sheet blocking tends to occur more frequently as the ambient temperature increases, the controller 34 actuates the air blower 323 when the ambient temperature measured by the temperature sensor 324 is 32° C. or higher. After actuating the air blower 323, the controller 34 increases the amount of air sent from the air blower 323 as the number of sheets counted by the counter 325 increases. Specifically, the controller 34 increases an average voltage supplied to the DC motor so as to rotate the fan at higher speed, thereby increasing the amount of air sent from the air blower 323.
With the image forming apparatus 1 according to the first exemplary embodiment, the sheets output by the pair of output rollers 333 and loaded onto the output tray 32 are cooled by the air blown out from the air holes 3221a, whereby the occurrence of sheet blocking may be prevented. Furthermore, in the image forming apparatus 1 according to the first exemplary embodiment, the air blower 323 is actuated when the number of output sheets is 100 or more. Therefore, when the number of output sheets is smaller than 100, a state where the sheets loaded on the output tray 32 are scattered about on the output tray 32 due to air blown out from the air holes 3221a, that is, a poorly accommodated state of the sheets loaded on the output tray 32, may reliably be avoided. Furthermore, in the image forming apparatus 1 according to the first exemplary embodiment, the air blower 323 is actuated when the ambient temperature is 32° C. or higher, so that power consumption may be reduced. Moreover, in the image forming apparatus 1 according to the first exemplary embodiment, the amount of air sent from the air blower 323 is increased with increasing number of output sheets, whereby a good accommodated state of the sheets loaded on the output tray 32 may be achieved.
The description of the image forming apparatus 1 according to the first exemplary embodiment of the present invention ends here. The following description relates to an image forming apparatus according to a second exemplary embodiment of the present invention. In the second exemplary embodiment, the countermeasure for preventing the occurrence of sheet blocking is different from that in the first exemplary embodiment described above.
In the following description, elements that are similar to those in the first exemplary embodiments are given the same reference numerals, and redundant descriptions will be omitted. The following description is directed to differences from the first exemplary embodiment.
An image forming unit 8 in an image forming apparatus 7 shown in
In addition to the pair of output rollers 333 (see
As shown in
As shown in
Furthermore, as shown in
As described above, because a sheet output by the pair of output rollers 333 has been heated by the heating mechanism 311a when traveling through the fixing device 310, the sheet carries heat. When an image forming operation and post-processing are performed in the apparatus including the image forming apparatus 7 equipped with the sheet transport device 91 and the post-processing device 92 connected to the image forming apparatus 7, the heat-carrying sheet is transported through the sheet transport device 91. The sheet transport device 91 is installed on the upper surface of the loading plate 821, and the four toner cartridges 362K, 362C, 362M, and 362Y are disposed at the underside of the loading plate 821. Therefore, when an image forming operation and post-processing are performed consecutively on multiple sheets, the heat carried by the sheets transported through the sheet transport device 91 may be transmitted to the four toner cartridges 362K, 362C, 362M, and 362Y, possibly resulting in a problem where the toners become fixed within the toner cartridges 362K, 362C, 362M, and 362Y. The air blower 823 and the exhaust fan 826 in the image forming unit 8 are provided as a countermeasure for preventing such a problem.
Specifically, as shown in
As shown in
Referring back to
As shown in
As shown in
As shown in
For preventing the occurrence of sheet blocking, a dedicated air blower for blowing air out from the air holes 8221a is not necessary in the image forming apparatus 7 according to the second exemplary embodiment.
The description of the image forming apparatus 7 according to the second exemplary embodiment of the present invention ends here.
The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Number | Date | Country | Kind |
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2012-245372 | Nov 2012 | JP | national |