JP2563913B2 - Image forming device cooling device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an internal cooling device of a plain paper copying machine (so-called PPC) capable of copying on a large size paper.

(Prior Art) There are mainly heat sources of an optical system (halogen lamp or fluorescent lamp) and a fixing system (heater) in the body of an electronic copying machine. A cooling device (fans) is provided so as to exhaust the above air to the outside of the machine body.

In particular, selenium and OPC, which are photoconductors, are crystallized when exposed to high temperatures and their characteristics deteriorate, which greatly affects the image quality.Therefore, place them so that they are not affected by heat from the optical system and fixing system. Has been done.

Moreover, in order to efficiently exhaust the air to the outside of the machine by the cooling device as described above, and to prevent the user of the copying machine from feeling uncomfortable, the exhaust direction has a variable directivity. See, for example, JP-A-61-95273).

By the way, in an electronic copying machine such as a PPC that can copy on a wide and large size paper, the shape of the device is enlarged in the left and right direction of the machine from the viewpoint of user convenience, The sheet is arranged in the longitudinal direction, and the sheet after transfer and fixing is discharged to the front surface of the machine body. Therefore, in this configuration, the fixing device, which is one of the heat sources, is disposed closer to the front side of the machine than the photoconductor, so that the interior of the machine, particularly around the photoconductor and the optical system, can be efficiently disposed. In order to achieve cooling, it is necessary to exhaust the air around these members inside the machine body to the front surface of the machine body.

The reason for this is that with a machine that is wide in the left-right direction, the amount of movement is longer in terms of hydrodynamics when exhausting from the left and right sides of the machine, and the exhaust efficiency is reduced. This is because the ambient atmosphere around the quantification device, which is a heat source, is also sucked, and the heat is likely to be exerted on the photoconductor.

However, in the configuration in which loose air is discharged to the front surface of the machine, that is, to the operating side, the user feels uncomfortable, and the heat around the fixing device is sucked and discharged directly to the outside of the machine.
On the contrary, the fixing device itself has to adopt a structure in which heat is prevented from being dissipated.

(Object of the Invention) The present invention has been made on the basis of the above background, in an image forming apparatus capable of copying on a wide and large size sheet and ejecting the sheet after transfer and fixing to the front of the machine, An object of the present invention is to provide a cooling device capable of efficiently exhausting the atmosphere of a photoconductor or the like without the heat of the fixing device acting on the photoconductor and reducing heat dissipation loss of the fixing device.

(Structure of the Invention) A cooling device for an image forming apparatus according to the present invention includes a photoconductor provided in the left-right direction in the machine, and an electrostatic latent image is formed on the surface of the photoconductor to visualize the paper. An image forming means for transferring the image onto the sheet, a fixing device arranged on the front side of the machine body with respect to the photoconductor, for fixing the transferred image on the sheet, and a sheet discharge path for conveying the sheet after fixing from the fixing device. And a fan that is provided on the front side of the photoconductor and sucks and exhausts the air inside the machine, and is provided between the fan and the paper discharge passage. And a guide for blowing air from the fan into the paper discharge passage in a direction substantially orthogonal to the paper discharge passage to exhaust the air.

With this configuration, the air warmed by the photoconductor or other optical system inside the machine body is sucked by the fan, and the air warmed by the fixing device is also sucked by the fan without flowing to the photoconductor side. Then, the sucked air is blown to the paper discharge passage of the paper discharge unit on the front side of the fixing device from the direction orthogonal to the paper discharge passage. A part of the air blown to the paper discharge passage is exhausted to the outside from the paper discharge port directed to the front, and a part of the air is directed to the rear and goes around to the fixing device side. Due to the air curtain caused by the warm air, the heat radiation loss of the fixing device itself is reduced.

(Embodiment) FIG. 1 shows an electronic copying machine according to an embodiment of the present invention.
This will be described with reference to FIG.

Inside the machine body 1, a photosensitive drum 2 having a long axis arranged in the left-right width direction (front and back direction of the paper in FIG. 1) is rotatably provided, and around the photosensitive drum 2, in the rotational direction. An exposure unit 5 for a document image by a known main charging device 3, an optical system 4 including an exposure lamp 4a and a lens 4b, a developing device 6, and the like.
Image forming means such as a transfer device 7, a separating device 8 and a cleaning device 9 are provided.

A fixing device 10 for fixing the image on the paper transferred and separated from the drum 2 is provided on the front side of the machine body 1, and the paper discharge section 11 after the fixing is provided on the front (operation side) housing of the machine body 1. It communicates with the formed discharge opening 12. Further, a paper ejection tray that curves forward and extends facing the paper ejection opening 12
13 is installed.

A sheet (transfer sheet) insertion port 14 is provided in the lower portion on the front side of the machine body 1, and the sheet feeding roller 1 is provided inside the insertion port 14.
5. A stopper 16 for correcting the leading edge of the sheet, a registration roller pair 17, and a conveyance roller pair 18 are provided, and a paper feed passage 19 between the registration roller pair 17 and the conveyance roller pair 18 is formed in a U shape. The passage on the downstream side of the pair of conveying rollers 18 is directed to the transfer device 7. Also, facing the passage between the separating device 8 and the fixing device 10, the sirocco or center fan 20
Is provided, which assists the separation of the sheet after transfer and stabilizes the conveyance of the sheet to the fixing device 10.

Further, an insertion port 21 for inserting a document is provided on the upper surface of the machine body 1, and a pair of document feed rollers 22, 2 is provided behind the insertion port 21.
3, a contact glass 24 and a document discharge tray 25 are provided.

Further, as a feature of the present invention, the atmosphere (peripheral air) of the drum 2 and the optical system 4 inside the machine body 1 is sucked up adjacent to the fixing device 10 and above the paper discharge section 11 after fixing. Further, an in-machine cooling exhaust fan 26 that blows (exhausts) air toward the paper discharge unit 11 is provided. This exhaust fan
The reference numeral 26 includes a cross flow fan (or a center fan) 26a and a blower guide plate 26b. The fixing device 10 includes a fixing roller 10a having a heater therein and a pressure belt 1 which is driven by being brought into contact with the fixing roller 10a with a predetermined pressure.
0b, an oil supply roller 10c that is in contact with the fixing roller 10a and prevents so-called offset, and a separation claw 10d.
After the fixing, the paper discharge section 11 after fixing is provided with upper and lower guide plates 27a and 27b forming a paper discharge passage, and upper and lower paper discharge rollers 28a and 28b facing the paper discharge opening 12. Further, the blowing direction of the exhaust fan 26 is substantially orthogonal to the discharge passage, and although not shown in the upper guide plate 27a, the exhaust air blown by being guided by the blowing guide plate 26b is provided. A flow port is formed so as to flow into the paper discharge passage.

In the figure, 29 is an operation unit, and 30 is a pattern for feeding a document with the center as a reference.

To explain the operation of the above configuration, a sheet is inserted from the front side of the machine body 1 through the sheet insertion port 14 in the direction of the arrow in FIG. 2, and a document is similarly inserted through the document insertion port 21. Then, various rollers and members are driven at a predetermined timing so that the front end of the image of the original and the front end of the paper coincide with each other on the photoconductor drum 2, and a transfer device from the photoconductor drum 2 to the paper is transferred to the paper by a so-called electrophotographic method. The image of the original is transferred at 7, and the paper is separated from the drum 2 by the separating device 8 with the help of the fan 20 and conveyed to the fixing device 10, where it is transferred between the fixing roller 10a and the pressure belt 10b. The transferred image on the sheet is fixed through the sheet.

After fixing, the paper is fed to the upper and lower guide plates 27a,
By driving the paper discharge rollers 28a and 28b through the paper discharge path by 27b, the paper is discharged onto the paper discharge tray 13 through the paper discharge opening 12.

At this time, by the operation of the exhaust fan 26, the air around the drum 2 and the optical system 4 inside the machine body 1 is sucked as shown in FIG. 1, and is blown to the paper discharge section 11 through the circulation port of the upper guide plate 27a. It is introduced into the paper discharge passage, and is further discharged from the machine body 1 having the paper discharge tray 13 through the paper discharge opening 12.

In this way, in the present invention, the heat is not directly discharged to the outside of the machine, but is exhausted to the paper discharge section 11 after fixing, so that there is little heat loss, and moreover, the user who is in front of the machine directly blows warm air. It does not cause any discomfort and does not cause discomfort. In particular, since the air curtain is made of warm air in the paper discharge unit 11, the heat of the fixing device 10 does not directly leak out of the machine as in the conventional case, and the heat radiation loss is reduced.

Further, since the paper after fixing does not come into direct contact with cold outside air and is cooled slowly, curling that occurs when the paper is rapidly cooled is reduced, and eventually the paper is transferred to the discharge tray 13. Alignment of the discharged sheets is good.

Furthermore, since the paper discharge opening 12 is also used as an exhaust port, it is not necessary to separately provide a member such as a louver on the machine body housing, cost reduction can be achieved, and the appearance is excellent. Become.

In the above embodiment, the present invention is exemplified by exemplifying an electronic copying machine in which a fixing device is disposed on the front side of the machine body rather than the photoconductor to transfer and fix an image, and then the paper is discharged to the front side of the machine body. As described in detail, as is well known in the art, electrophotographic printers, facsimiles, and the like include apparatuses of the type having the same configuration as the electronic copying machine, and the present invention is applied to these image forming apparatuses. By doing so, it is clear that the same effect as in the case of the electronic copying machine can be obtained. Therefore, the application of the present invention is not limited to the above electronic copying machine. The present invention forms an electrostatic latent image on the surface of a photoconductor, visualizes it, and transfers it to paper. The present invention can be applied to all image forming apparatuses that fix a transferred image on a sheet by a fixing device arranged on the front side of the machine body, and then discharge the paper to the front side of the machine body.

(Effects of the Invention) According to the present invention as described above, a fan that sucks air in the machine body and exhausts the air to the paper discharge unit directs the air blowing direction in a direction substantially orthogonal to the paper discharge passage of the paper discharge unit. I did so,
Compared to the case where the air is exhausted directly to the outside of the machine, the air is effectively exhausted, but with this exhaust, the same effect as forming an air curtain of warm air is formed for the fixing device, and the fixing device is performed. The heat dissipation loss of itself can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional side view of an electronic copying machine having a cooling device according to an embodiment of the present invention, and FIG. 2 is an external view of the same machine. 1 ... Machine, 2 ... Photosensitive drum, 7 ... Transfer device, 10
…… Fixing device, 11 …… Paper ejection section, 12 …… Paper ejection opening, 26…
… Exhaust fan, 27a… Guide plate.

Claims (1)

(57) [Claims] 1. A photoconductor provided in the left-right direction in the machine, an image forming unit for forming an electrostatic latent image on the surface of the photoconductor, visualizing the latent image, and transferring the image onto a sheet. Is also arranged on the front side of the machine body, and has a fixing device for fixing the transferred image to the paper, and a paper discharge path for conveying the paper after fixing from the fixing device, and a paper discharge section having a paper discharge port on the front surface of the machine body. A fan that is provided on the front side of the photoconductor and sucks and exhausts the air in the machine body; and a fan that is provided between the fan and the paper discharge passage, and discharges the air from the fan to the paper discharge passage. A cooling device for an image forming apparatus, comprising: a guide that blows air to the paper discharge passage to exhaust air from a direction substantially orthogonal thereto.