JP2004037992A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems of a high cost and an insufficient cooling capability with respect to cooling techniques for suppressing the temperature rise in an image forming apparatus. <P>SOLUTION: A carrying line for a recording material subjected to fixing processing is provided along a housing of the apparatus, and a cooling wind introduced from the outside is directly blown to the recording material carried in the carrying line. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly, to a cooling technique for suppressing a temperature rise in the image forming apparatus.
[0002]
[Prior art]
2. Description of the Related Art In an electrophotographic image forming apparatus, a heat source is generally provided in the apparatus in order to thermally fix a toner image, and a measure is taken against a rise in temperature in the apparatus due to heat from the heat source. In particular, in an image forming apparatus having a double-sided image forming function of forming an image on the back surface of the recording material by re-feeding the recording material passing through the fixing device to the image forming unit, the recording material heated by the fixing device is In order to suppress a rise in the temperature inside the apparatus due to the paper being fed to the image forming unit, a cooling unit for cooling the re-fed recording material is provided.
[0003]
With reference to FIG. 1 showing an image forming apparatus according to an embodiment of the present invention, a conventional cooling means for cooling a re-fed recording material will be described.
[0004]
The conventional cooling means is provided in an empty space of the re-feeding conveyance path. As shown in the figure, cooling means F1 and F2 are provided below the fixing device 38 and cooling means F3 and F4 are provided near the reversing section 72. F1 and F2 indicate two cooling means provided on the near side and the back side of the apparatus, and F3 and F4 also indicate two cooling means provided on the near side and the back side of the apparatus.
[0005]
[Problems to be solved by the invention]
Since the conventional cooling units F1 to F4 are provided separately from the outside by a structure such as a transport path, it is difficult to introduce cooling air from the outside to the cooling units F1 to F4. That is, in order to introduce cooling air from the outside to the cooling means F1 to F4, there is a problem that a space for providing a duct is required and the apparatus becomes large. In order to avoid an increase in the size of the apparatus, conventional cooling means, that is, cooling means F1 to F4, cool the recording material by blowing air inside the apparatus onto the recording material.
[0006]
For this reason, the conventional cooling means does not have sufficient cooling capacity, and it is necessary to provide four cooling means F1 to F4 as shown in FIG. For this reason, in addition to the problem that the device becomes large and the cost increases, there is a problem that a sufficient cooling capacity cannot be obtained.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problem in a conventional cooling unit that cools a recording material subjected to a fixing process.
[0008]
[Means for Solving the Problems]
The above object of the present invention is achieved by the following invention.
[0009]
1. Image forming unit,
A fixing device for fixing the toner image formed on the recording material in the image forming unit;
A conveying path for conveying the recording material fixed by the fixing device, a reversing conveying path having a portion for conveying the recording material along the exterior of the apparatus,
Cooling means for blowing the cooling air introduced through the cooling air introduction port provided on the exterior to the portion,
An image forming apparatus comprising:
[0010]
2. 2. The image forming apparatus according to claim 1, further comprising an exhaust unit configured to exhaust air blown to the portion.
[0011]
3. 3. The image forming apparatus according to the above item 1 or 2, further comprising a decurler provided between the fixing device and the portion.
[0012]
4. A post-processing apparatus, wherein the introduction port is provided at a boundary between the image forming apparatus main body and the post-processing apparatus, and the introduction port of the introduction port in the image forming apparatus in which a paper discharge tray is provided instead of the post-processing apparatus. The image forming apparatus according to any one of the above items 1 to 3, wherein a shield is removed.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention.
[0014]
The image forming apparatus includes an automatic document feeder 1, an image reading unit 2, an image forming unit 3, a recording material storage unit 4, a transport unit 5, and a paper discharge / re-feed unit 6.
[0015]
The automatic document feeder 1 is provided at an upper portion of the image forming apparatus, is a device that feeds out a document one by one, conveys the document to an image reading position, and discharges the document after the image reading is completed. The automatic document feeder 1 includes a document table 11 on which a document is placed, a document separation unit 12 for separating the documents placed on the document table 11 one by one, and transports the documents separated by the document separation unit 12. Document feeder 13, a document discharge unit 14 for discharging a document conveyed by the document conveyer 13, a document discharge table 15 on which documents discharged by the document discharge unit 14 are stacked, and both sides of the document. It has a document reversing unit 16 for reversing the front and back of a document when reading an image.
[0016]
A plurality of documents placed on the document table 11 are separated by the document separation unit 12 and are transported one by one. The document separated and conveyed by the document separation unit 12 is conveyed by the document conveyance unit 13 and read by the image reading unit 2 provided below the automatic document feeder 1. The read document is discharged to a document discharge table 15 by a document discharge unit 14. When reading the image on both sides of the document, the document from which the image on the front surface has been read is turned over by the document reversing unit 16, conveyed again by the document conveying unit 13, and the image on the back surface is read. Then, the document from which the image on the back side has been read is discharged by the document discharge unit 14 onto the document discharge table 15.
[0017]
Further, the automatic document feeder 1 is configured to be integrally retractable, and the original can be placed on the platen glass 22 by raising the automatic document feeder 1 and opening the platen glass 22. It is configured to be able to. As described above, the present embodiment includes a reading mode for reading a document conveyed by the document conveying unit 13 and a reading mode for reading a document placed on the platen glass 22.
[0018]
The image reading unit 2 is a unit that reads an image of a document and generates image data, and is provided at an upper part of the image forming apparatus. The image reading unit 2 includes a slit 21 for reading an image of a document conveyed and traveling by the document conveying unit 13 of the automatic document feeder 1, a platen glass 22 serving as a document table for placing the document, and irradiating the document with light. A first mirror unit 23 in which a lamp 231 that is a light source that emits light and a first mirror 232 that reflects light reflected from a document are integrated; a second mirror 241 and a third mirror 242 that reflect light from the first mirror 232; Unit 25, an image forming lens 25 serving as an image forming unit for forming reflected light from a document on the slit 21 or the platen glass 22 on the CCD 26, and a light image formed by the image forming lens 25. Has a line-shaped CCD 26 that photoelectrically converts the image data to generate an image signal.
[0019]
In a reading mode in which the image reading unit 2 reads a document fed by the automatic document feeder 1, the first mirror unit 23 and the V mirror unit 24 are stationary. The light reflected from the document enters the CCD 26 via the first mirror 232, the second mirror 241, the third mirror 242, and the imaging lens 25. The CCD 26 photoelectrically converts the incident light to read the image of the document in the main scanning direction. On the other hand, since the document is moved in the sub-scanning direction by the document transport unit 13, the image of the entire document is read to generate image data. I do.
[0020]
In the reading mode for reading a document placed on the platen glass 22, the first mirror unit 23 and the V mirror unit 24 move along the platen glass 22 to scan and read the document.
[0021]
The image forming unit 3 forms an image on a recording material based on image data generated by the image reading unit 2 or received from outside. The image forming unit 3 forms an image by an electrophotographic process. The image forming unit 3 includes a photosensitive drum 31 having a photoconductive photosensitive layer and carrying a toner image. A charging device 32, a developing device 34, a transfer device 35, a separating device 36, and a cleaning device 37 are arranged around the device. An exposure device 33 that performs scanning exposure by laser is arranged so as to perform exposure between the charging device 32 and the developing device 34. Reference numeral 38 denotes a fixing device for fixing the toner image on the recording material formed in the image forming unit 3.
[0022]
The photoconductor drum 31 is driven and rotated by a driving unit (not shown), and a toner image is formed on the photoconductor drum 31 by charging, exposure, and development, and the formed toner image is transferred to a recording material by a transfer device 35. You. The recording material on which the toner image has been transferred is separated from the photosensitive drum 31 by the separating device 36 and is conveyed to the fixing device 38. The recording material storage unit 4 is a storage unit that stores a plurality of recording materials in a stacked state. The paper discharge / re-feed unit 6 is a unit for discharging or reversing the recording material conveyed by the conveyance unit 5 and formed on the image forming unit 3 and re-feeding the recording material to the photosensitive drum 31. The discharge / re-feed unit 6 includes a switching member 62 that switches between a conveyance path for directly discharging the recording material that has passed through the fixing device 38 to the outside of the apparatus and a conveyance path for reversing the recording material. A paper discharge roller 63 for discharging the paper to the outside, a paper discharge tray 64 provided on a side surface of the apparatus for loading the recording material discharged by the paper discharge roller 63, and a reversing conveyance path 68 for reversing the recording material and discharging the paper. Guide members 68A, 68B and 68C (shown in FIG. 2), a reversing section 72 for reversing the front and back of the recording material in the back surface image formation, and a back surface image forming device for conveying the reversed recording material toward the registration roller 56. It has a paper feeding unit 71. The reversing conveyance path 68 is also used as a conveyance path for introducing a recording material into the reversing unit 72 and the back-side image forming paper supply unit 71.
[0023]
In the one-sided mode in which the paper is discharged with the image side up, the recording material that has passed through the fixing device 38 is guided straight by the switching member 62, is discharged to the paper discharge tray 64, and is discharged with the image side down. In the single-sided mode, the recording material that has passed through the fixing device 38 is guided by the switching member 62 and proceeds downward on the reversing conveyance path 68, and when the rear end passes the switching member 62, the traveling direction is reversed and discharged. The paper advances upward toward the paper roller 63, and is discharged to the paper discharge tray 64 via the paper discharge roller 63.
[0024]
In the back side image forming process in the duplex mode, the recording material that has passed through the fixing device 38 is guided by the switching member 62 and proceeds downward on the reversing conveyance path 68, and is switched back by the reversing unit 72 to be turned upside down. The sheet advances to the registration roller 56 via the back-side image forming sheet feeding unit 71. The reversing conveyance path 68 is provided along the exterior 100 (shown in FIGS. 2 and 3) of the image forming apparatus as shown.
[0025]
In the present embodiment, cooling means for cooling the recording material traveling on the reversing conveyance path 68 is provided. Next, cooling of the recording material will be described with reference to FIGS. FIG. 2 is a front sectional view of the cooling unit, and FIG. 3 is a side view of the cooling unit.
[0026]
The fixing device 38 includes a heating roller 39 provided with a heat source H formed of a halogen lamp inside, a pressing roller 40 that presses against the heating roller 39, a cleaning device 41 that cleans the surface of the heating roller 39, and a fixing device 38 that fixes the recording material P. , An ejection guide 43, and a fixing ejection roller 61. The recording material P carrying the unfixed toner image on the upper surface enters from the introduction guide 42, is subjected to a fixing process at a nip between the heating roller 39 and the pressure roller 40, and is guided by the paper ejection guide 43 to be fixed and discharged. Is discharged from the fixing device 38.
[0027]
In the case of one-sided image forming reverse sheet discharging and two-sided image forming backside image forming, the recording material P is guided by the switching member 62 set at the position indicated by the chain line after passing the fixing sheet discharging roller 61, and is conveyed by the conveying roller 67. And travels down the reversing conveyance path 68, is conveyed by the conveyance rollers 69 and enters the reversing section 72.
[0028]
In the fixing process, the recording material P undergoes a bending action in a nip between the heating roller 39 and the pressure roller 40 together with the heating. In the illustrated example, the heating roller 39 is formed of a roller called a hard roller in which a release layer of a fluororesin or the like is provided on the base of a metal pipe, and the pressure roller 40 is formed of a base made of a metal pipe such as silicon rubber. Since the recording material P is formed of a roller called a soft roller provided with a heat-resistant elastic layer, the recording material P is curled in the nip by a bending action such that the upper surface becomes concave during the fixing process.
[0029]
In the present embodiment, a decurler for forming a conveyance path for bending the recording material P in a direction opposite to the curl by the discharge guide 43, the fixing discharge roller 61, the switching member 62, and the conveyance roller 67 is configured. The curl is corrected.
[0030]
In the fixing process, the recording material P is subjected to the above-mentioned bending action and is heated to increase its temperature. When a high-temperature recording material P is introduced into the image forming unit 3 (shown in FIG. 1) in the back-side image formation, process conditions change, such as raising the temperature of the photosensitive drum 31 (shown in FIG. 1). .
[0031]
In the present embodiment, inlets 100A (front side) and 100B (rear side) of the cooling air AIR are provided on the exterior 100 of the apparatus, and air inlets as cooling means corresponding to the inlets 100A and 100B are provided. Fans F5 (front side) and F6 (rear side) are provided to cool the recording material P traveling on the reversing conveyance path 68. The cooling air AIR is exhausted from an exhaust port 100C by an exhaust fan F7 attached to an exterior 100 forming the back surface of the apparatus. As shown in the figure, since the reversing transport path 68 has a transport path portion substantially parallel to the exterior 100 of the apparatus, the outside air travels directly from the introduction ports 100A and 100B provided in the exterior 100 on the reversing transport path 68. The recording material P can be sprayed.
[0032]
In the reversal discharge of the single-sided image formation, the recording material P is guided by the switching member 62 when traveling down the reversing conveyance path 68 and when the recording material P is guided by the switching member 66 from the reversing conveyance path 68 to the discharge rollers 63. When it rises to, it is cooled by the cooling air AIR introduced by the fans F5 and F6.
[0033]
As described above, since the cooling air AIR, which is fresh air introduced from the introduction ports 100A and 100B provided in the exterior 100 of the apparatus, is blown onto the recording material P to cool the recording material P, the cooling effect is high and the cooling effect is high. It is possible to sufficiently cool the recording material P only by providing the cooling means at the locations. In addition, a sufficient cooling effect can be obtained with a fan having a relatively low output. Further, by providing the fan F7 as a means for exhausting the cooling air AIR, the cooling effect is further improved. Further, the cooling air AIR is formed by the fans F5 and F6 arranged below and the fan F7 arranged above. Is formed along the reversing conveyance path 68, and the cooling air AIR cools the recording material P passing through the decurler, so that the curl of the recording material P can be satisfactorily corrected.
[0034]
In the reverse side image formation, the recording material P that has passed through the reversing conveyance path 68 travels rightward in FIG. 2 through the reversing unit 72, and the rear end of the recording material P traveling rightward is conveyed by the conveyance roller 69 and the switching member 75. , The reversing roller 76 reverses and conveys the recording material P to the left, and advances the recording material P to the back-side image forming paper supply unit 71. The reversing control of the reversing roller 76 is performed based on the leading end detection signal of the recording material P when the sensor 73 travels rightward. The switching member 75 is urged so that the solid line position in the drawing becomes the steady position. When the recording material P travels to the right, the recording material P is displaced to the position indicated by the chain line by the recording material P, but travels to the left. In some cases, the recording material P is displaced to the position indicated by the solid line to guide the leading end of the recording material P to the back-side image forming sheet feeding unit 71. Reference numeral 74 denotes a sensor for synchronizing the conveyance of the recording material P in the back-side image forming paper supply unit 71 with the registration roller 56.
[0035]
FIG. 4 is a front sectional view of a part of a cooling unit in the image forming apparatus formed by connecting the post-processing apparatus FS to the image forming apparatus main body instead of the sheet discharge tray 64. The image forming apparatus to which the post-processing apparatus FS is connected will be described in comparison with the image forming apparatus having the paper output tray 64 shown in FIGS.
[0036]
In the image forming apparatus shown in FIGS. 2 and 3, the paper discharge tray 64 is supported by a support plate 101 fixed to the exterior 100. However, when the post-processing device FS is connected to the image forming apparatus, the support plate 101 Then, the paper discharge tray 64 is removed, and the post-processing device FS is fixed to the exterior 100. As a result, in the image forming apparatus to which the paper discharge tray 64 shown in FIGS. 2 and 3 is attached, as shown in FIG. 3, a part of the cooling air AIR inlets 100A and 100B is a paper discharge tray 64 that is a shield. Although closed, when the post-processing device FS is connected, the entire area of the inlets 100A and 100B functions because there is no support plate 101.
[0037]
When the cooling air AIR is introduced from the gap between the image forming apparatus and the post-processing apparatus as well as from the inside of the post-processing apparatus FS as shown in FIG. 4, there is a concern that the cooling effect is slightly reduced. When the post-processing device FS is connected, the power of the fan as a cooling means can be changed by removing the shield when the discharge tray is mounted on the printer and increasing the area of the introduction port. The desired cooling effect is maintained without modification.
[0038]
【The invention's effect】
According to the first aspect of the invention, since fresh air introduced from the outside is directly blown onto the recording material on which the fixing process has been performed, the recording material can be efficiently cooled. Thus, the necessary cooling of the recording material can be performed, and the cost can be reduced.
[0039]
According to the second aspect, a higher cooling effect can be obtained.
According to the third aspect, the curl of the recording material can be satisfactorily corrected.
[0040]
According to the fourth aspect, it is possible to prevent a decrease in cooling performance that occurs when a post-processing device is connected.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a front sectional view of a cooling unit.
FIG. 3 is a side view of a cooling unit.
FIG. 4 is a partial front sectional view of a cooling unit of the image forming apparatus to which a post-processing device is connected.
[Explanation of symbols]
64 discharge tray 68 reversing conveyance path 100 exterior 100A, 100B introduction port 100C exhaust port 101 support plates F1 to F4 cooling means F5 to F7 fan

Claims (4)

Image forming unit,
A fixing device for fixing the toner image formed on the recording material in the image forming unit;
A conveying path for conveying the recording material fixed by the fixing device, a reversing conveying path having a portion for conveying the recording material along the exterior of the apparatus,
Cooling means for blowing the cooling air introduced through the cooling air introduction port provided on the exterior to the portion,
An image forming apparatus comprising: The image forming apparatus according to claim 1, further comprising an exhaust unit configured to exhaust air blown to the portion. The image forming apparatus according to claim 1, further comprising a decurler provided between the fixing device and the portion. A post-processing apparatus, wherein the introduction port is provided at a boundary between the image forming apparatus main body and the post-processing apparatus, and the introduction port of the introduction port in the image forming apparatus in which a paper discharge tray is provided instead of the post-processing apparatus. The image forming apparatus according to claim 1, wherein the shield is removed.

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