JP2002072729A - Image forming apparatus - Google Patents

Abstract

(57) Abstract: An image forming apparatus that can prevent sticking of a discharged sheet without increasing costs and increasing the size of the apparatus. SOLUTION: After a toner image is transferred, fixing means 18 is provided.
The sheet on which the toner image has been fixed by the heating is discharged from a plurality of outlets 50, 51 provided in the apparatus main body 31 to a plurality of sheet stacking units 20, 21, respectively. Then, a plurality of outlets 5 are provided by a common cooling means constituted by the sheet cooling fan 106 and the duct member 113.
The sheets are cooled by blowing air toward the sheets respectively discharged from the sheets 0 and 51 or the sheets discharged to the plurality of sheet stacking units 20 and 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus, and more particularly, to cooling of a sheet discharged after an image is formed.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus to which an electrophotographic system is applied, a toner image formed on a photosensitive drum is transferred to a sheet, and then heated by a fixing unit to fix the toner image on the sheet. I have to.

FIG. 5 is a diagram showing a schematic configuration of a laser printer which is an example of such a conventional image forming apparatus.
In the figure, reference numeral 30 denotes a laser printer, and 31 denotes a laser printer main body (hereinafter, referred to as an apparatus main body).

A scanner unit 1 includes an optical unit for irradiating and scanning a laser beam in accordance with image information and a scanning unit. A process cartridge 10 forms an image forming unit. A photoconductor drum 3, a roller charger 4 made of semiconductive rubber, a developing device 5 for developing a latent image on the photoconductor drum 3 with toner 6, and a cleaner 8 for removing waste toner from the photoconductor drum 3 are incorporated. Have been.

Here, the photosensitive drum 3 in the process cartridge 10 rotates in the direction of the arrow and the surface thereof is uniformly charged by the roller charger 4, and then the laser beam L from the scanner unit 1 is irradiated with the laser light L. Irradiation via the mirror 2 forms an electrostatic latent image on the surface. The electrostatic latent image is visualized as a toner image by the toner 6 supplied by the developing device 5. Reference numeral 7 denotes a transfer roller that contacts the photosensitive drum 3 and forms a transfer unit.

On the other hand, in FIG. 1, reference numeral 11 denotes a paper feed cassette for storing a transfer material 12 which is a sheet. The transfer material 12 stored in the paper feed cassette 11 is separated one by one by a paper feed roller 13. Up and down guide 1
4 and is conveyed to a pair of registration rollers 15.

Here, when the transfer material 12 is conveyed in this manner, the registration roller pair 15 is stopped, and the tip of the transfer material 12 abuts on the registration roller pair 15 in the stopped state, so that the transfer material 12 The skew is corrected. After correcting the skew of the transfer material 12 in this way, the registration roller pair 15 starts rotating so as to synchronize with the leading end of the image formed on the photosensitive drum 3, and transfers the transfer material 12 to the transfer unit. Conveyed to.

A paper feed sensor (not shown) is provided near the registration roller pair 15, and a control unit (not shown) controls the paper feed state, the jam, and the length of the transfer material by the paper feed sensor. Etc. are detected.

On the other hand, the transfer material 12 conveyed to the transfer section in this way is provided with a charge having a polarity opposite to that of the toner from the back side by the transfer roller 7, whereby the toner image formed on the photosensitive drum 3 is formed. The image is transferred to the transfer material 12.

The transfer material 12 onto which the toner image has been transferred as described above is conveyed to a fixing device 18 by conveyance rollers 17 and a conveyance guide 16, and is heated and pressed by the fixing device 18 to transfer the toner image. The unfixed toner image on the material 12 is dissolved and fixed, and is fixed on the transfer material 12 as a permanent image.

After that, the transfer material 12 on which the toner image is fixed is selectively discharged by the flapper 19 to the first discharge port 50.
The FU (face-up) tray 21 provided on the side surface of the apparatus main body 31 with the final print surface facing up, or the FD (face-down) tray provided on the upper surface of the apparatus main body 31 from the second discharge port 51 The paper 20 is discharged with the final print surface down.

[0012]

However, in such a conventional image forming apparatus, particularly in a high-speed machine in which 40 or more images are formed per minute, the transfer material is discharged onto a tray at a high speed. Before the discharged toner on the transfer material solidifies, the next high-temperature transfer material is discharged and stacked. For this reason, heat is accumulated in the transfer material, so that the toner does not solidify, and the previously discharged transfer material may adhere to the next discharged transfer material.

In a color image forming apparatus, for example, using a toner which softens at a relatively low temperature, this sticking phenomenon easily occurs. Further, this phenomenon is caused by a high temperature environment, a thin paper having a small heat capacity and a surface property. Is likely to occur at the time of smooth paper, OHT, or a high printing rate. Further, this tendency is remarkable in a device in which the distance from the fixing device 18 to the discharge ports 50 and 51 is short and it is difficult to naturally cool the transfer material during conveyance.

Therefore, as a countermeasure, the transfer material 12 is transferred to the FU tray 21 or the FD tray 20 as shown in FIG.
In this case, fans 22 and 23 for blowing outside air to the transfer material are respectively installed in the paper discharge passages R1 and R2 conveyed toward the transfer member.

However, as described above, the two paper discharge paths R1,
When the fans 22 and 23 are installed in the R2, respectively, the cost is increased and the size of the apparatus is increased. In addition, the exhaust air is blocked by the outside air blown by the fans 22 and 23, and the temperature inside the main body is increased. There was a problem.

Accordingly, the present invention has been made in view of such circumstances, and it is possible to prevent sticking of a discharged transfer material (sheet) without increasing costs and increasing the size of the apparatus. It is an object to provide an image forming apparatus.

[0017]

According to the present invention, there is provided an image forming apparatus in which after a toner image is transferred, a sheet on which the toner image is fixed is discharged to a plurality of sheet stacking units by heating by a fixing unit. A plurality of outlets provided in the apparatus main body and configured to discharge the sheet on which the toner image is fixed to the plurality of sheet stacking units; and a sheet or the plurality of sheet stacking units respectively discharged from the plurality of outlets. And a common cooling means for blowing air toward the sheet discharged to cool the sheet.

Further, in the invention, it is preferable that the common cooling means includes a blower fan for sucking outside air into the apparatus main body, and the outside air sucked by the blower fan being outside each of the plurality of outlets or the outlets. A duct member that forms an air passage that blows out toward the sheet stacking portion located below.

Further, in the present invention, the common cooling means includes an exhaust fan for exhausting air in the apparatus main body to the outside, and a part of the air in the apparatus main body exhausted by the exhaust fan. A duct member that forms an air passage that blows out toward the sheet stacking portion located outside the outlet or below the discharge port.

Further, the present invention is characterized in that outside air is sucked at the time of the exhaust, and the air inside the apparatus main body is discharged to the outside together with the outside air.

Further, in the invention, it is preferable that the common cooling means includes a blower fan for sucking outside air into the apparatus main body, and the outside air sucked by the blower fan being outside each of the plurality of outlets or the outlets. A duct member that forms an air passage that blows out toward the sheet stacking portion located below, an exhaust fan that exhausts air inside the apparatus main body to the outside, and a part of air in the apparatus main body that is exhausted by the exhaust fan And a duct member that forms another air path that blows out toward the sheet stacking portion located outside or below the plurality of discharge ports. is there.

Further, the present invention is characterized in that the exhaust fan is provided on both sides of the blower fan, and the other air path is provided on both sides of the air path. Further, the present invention includes switching means for selectively switching a discharge port for discharging a sheet, and a conveyance path for guiding the sheet from the switching means to one discharge port, wherein the common cooling means includes a blowing fan, A duct member for forming an air flow path for blowing an air flow formed by a fan toward the sheet stacking portion located outside or below the plurality of discharge ports, respectively, wherein the air path is It is characterized in that it is formed between the road and the cover of the apparatus body.

Further, as in the present invention, after the toner image is transferred, the sheet on which the toner image is fixed by heating by the fixing means is transferred from a plurality of discharge ports provided in the apparatus main body to a plurality of sheet stacking sections. To be discharged. Then, the sheet is cooled by blowing air toward the sheet discharged from the plurality of discharge ports or the sheet discharged to the plurality of sheet stacking units by the common cooling unit.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a paper discharge unit of the image forming apparatus according to the first embodiment of the present invention. In the same figure, the same reference numerals as those in FIG. 5 indicate the same or corresponding parts.

In FIG. 1, reference numeral 106 denotes a sheet cooling fan which is a blower fan for sucking outside air. In this embodiment, the sheet cooling fan 106 is, for example, M
INEBEA (NMB MODEL 3110KL-
05W-B49), an axial fan having a drive voltage of 24 V, 0.13 A, and an air volume of 1.10 m ³ / min is used.

Reference numeral 113 denotes a duct member provided in the apparatus main body and constituting a common cooling means together with the sheet cooling fan 106. The duct member 113 is provided between the upper surface cover 111 forming the upper surface of the apparatus main body 31 and the paper. Cooling fan 1
06, the outside air sucked as indicated by an arrow 107 is supplied to the outside of the second discharge port 51 and the second air as indicated by an arrow 108.
The outside air sucked by the sheet cooling fan 106 between the first air path D1 that blows out toward the FD sheet discharge tray 20 located below the discharge port 51 and the horizontal cover 112 that forms the side surface of the apparatus main body 31 is indicated by an arrow. As shown in 109, the FU located outside the first outlet 50 and below the first outlet 50
A second air path D2 that blows out toward the discharge tray 21 is formed.

The outside air sucked by the sheet cooling fan 106 is supplied to the duct member 113 by the sheet discharge passages R1, R2.
In order to prevent the exhaust heat from being blown into the discharge passage, the discharge passages R1, R2 and the first and second air passages D1, D2 are basically provided.
Although there is a function of shutting off, there may be a gap as long as there is no problem in raising the temperature inside the apparatus main body.

Therefore, in this embodiment, a plurality of ribs 114 facing the paper discharge passage R2 are provided in the duct member 113 as shown in FIG. Blowout opening 115
Is provided. And this blowing opening 1
By blowing outside air from 15 onto the transfer material passing through the paper discharge passage R2, the transfer material can be further cooled.

In FIG. 1, reference numeral 110 denotes the horizontal cover 1.
A louver provided on the upper part of the numeral 12 and a first outlet 5
Reference numeral 104 denotes an FD discharge roller provided in the second discharge port 51. Reference numeral 104 denotes an FD discharge roller provided in the second discharge port 51. Reference numerals 100 and 101 denote upper and lower guides for guiding the transfer material sent from the fixing device 18.

Next, the sheet cooling operation of the image forming apparatus thus configured will be described.

After the toner image is transferred by the transfer unit, the transfer material on which the toner image is fixed by the fixing device 18 is guided to the upper guide 100 and the lower guide 101, and is selectively guided by the flapper 19 as a switching means. You. That is,
When the flapper 19 is at the position of the two-dot chain line 102, it is sent to the FU paper discharge tray 21 through the paper discharge passage R1, and when it is at the position of the solid line, it is sent to the FD paper discharge tray 20 through the paper discharge passage R2.

On the other hand, the sheet cooling fan 106
Outside air is sucked in the direction of
The transfer material and the paper discharge tray that are discharged from the first and second discharge ports 50 and 51 through the paper discharge passages R1 and R2 by blowing the outside air in this manner. The transfer material discharged to the sheets 20 and 21 can be cooled.

As described above, each of the paper discharge passages R1, R
2, the first and second paper cooling fans 106 provided in one place as in the present embodiment.
By cooling the transfer material discharged from the discharge ports 50 and 51 and the transfer material stacked on the paper discharge trays 20 and 21, respectively, the problem of sticking to both paper discharges can be prevented without increasing the cost and increasing the size of the apparatus. Can be solved.

Further, by forming the first and second air paths D1 and D2 so as not to affect the inside of the apparatus main body, heat of the fixing device 18 flows back into the apparatus main body due to the sucked outside air. The increase in static pressure does not hinder exhaust heat.

In the above description, the case where one sheet cooling fan 106 is provided at one location has been described. However, when the width of the transfer material is significantly larger than the size of the sheet cooling fan 106, A plurality of sheet cooling fans 106 may be arranged side by side in the width direction of the transfer material. here,
As the sheet cooling fan 106, a cross-flow fan that is convenient for covering the longitudinal direction may be used, but using the above-described axial flow fan makes it inexpensive to use a plurality.

Next, a second embodiment of the present invention will be described.

FIG. 2 is a perspective view of the image forming apparatus according to the present embodiment, and FIG. 3 is a diagram showing a configuration of a paper discharge unit. 2 and 3, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

2 and 3, reference numeral 202 denotes an exhaust fan for exhausting the air inside the main body, and the exhaust fan 202 is the sheet cooling fan 106 shown in FIG.
Are provided on both sides.

Accordingly, the outside air sucked in the direction of arrow 107 by the sheet cooling fan 106 provided in the center is blown out to the FD tray 20 as shown by arrow 108 and the FD is also shown by arrow 109 Air is blown out to the tray 21 and air inside the main body is exhausted by an exhaust fan 202 provided on both sides of the sheet cooling fan 106 from an exhaust port 210 provided in the horizontal cover 112 as shown by an arrow 200. Has become.

In the present embodiment, a part of the exhaust gas from the exhaust fan 202 is blown out to the FU tray 21 as shown by an arrow 201. here,
In FIG. 3, reference numeral 204 denotes an inner guide which is a duct member constituting a common cooling unit together with the exhaust fan 202.
The inner guide 204 and the lateral cover 112 form a third air passage D3 for blowing exhaust gas to the FU tray 21.

By blowing the exhaust gas from the exhaust fan 202 to the FU tray 21 as described above, the exhaust gas can be blown over the entire transfer material width of the FU tray 21. In the figure, reference numeral 206 denotes a partition duct, which separates the outside air from the sheet cooling fan 106 and the exhaust air from the exhaust fan 202.

The exhaust fan 202 actively exhausts the hot air indicated by the arrow 205 rising from the gap between the rib-shaped paper passing means.
Here, due to the exhaust heat inside the apparatus main body, the temperature of the exhaust air blown out to the FU tray 21 by the temperature of the exhaust air is, for example, 3 ° C.
In the case of 0 degree, it becomes 45 degrees. However, even if the exhaust gas temperature becomes such a temperature, the temperature of the transfer material discharged after the fixing becomes about 90 degrees, so that there is a sufficient cooling effect.

As described above, in the system including the exhaust fan 202, the exhaust by the exhaust fan 202 and the outside air by the sheet cooling fan 106 are blown out to the FU tray 21. By providing the configuration and sharing the blowing of air to the FU tray 21, the blowing of air to the FU tray 21 is realized over the entire paper width direction.

The air blown out to the FD tray 20 by the sheet cooling fan 106 spreads in the width direction of the transfer material as shown by 108 in FIG. 2, and the blowing of air to the FD tray 20 spreads over the entire sheet width. Realized across. As a result, the discharged transfer material is cooled over the entire width of the transfer material, and as a result, the discharged paper stacking temperature is reduced, and sticking of the discharged paper can be prevented.

In this embodiment, the louver 207 is provided below the FU tray 21 as shown in FIG. 3, so that when the exhaust fan 202 exhausts air, the outside air is sucked as indicated by an arrow 208. It has become. And by performing the suction of outside air in this way,
The outside air is mixed with the exhaust gas 205, so that the temperature of the entire paper discharge passage is lowered. As a result, the temperature of the transfer material is lowered while the paper is passing through the paper discharge passage, and the discharged paper stacking temperature is further lowered.

Next, a third embodiment of the present invention will be described.

FIG. 4 is a diagram showing a configuration of a paper discharge unit of the image forming apparatus according to the present embodiment. In the figure,
The same reference numerals as those in FIG. 1 indicate the same or corresponding parts.

In the figure, reference numeral 300 denotes an exhaust fan, which exhausts hot air in the apparatus main body as indicated by an arrow 306.

Reference numeral 310 denotes a first duct member which constitutes a common cooling unit together with the exhaust fan 300. The first duct member 310 transmits exhaust air blown by the exhaust fan 300 to the upper surface cover 111 by an arrow 302. As shown in FIG. 1, a first air path D1 that blows out to the FD discharge tray 20 is formed.

Reference numeral 311 denotes a second duct member which constitutes a common cooling means together with the exhaust fan 300. The second duct member 311 transfers the exhaust blown by the exhaust fan 300 to the horizontal cover 112 by an arrow 305. As shown in (2), a second air path D2 that blows out to the FU discharge tray 21 is formed.

Reference numeral 304 denotes an exhaust port provided with a louver 303. In the present embodiment, the exhaust port 30
The area of 4 is smaller than the exhaust blowout area of the exhaust fan 300. As a result, of the exhaust gas exhausted by the exhaust fan 300, the exhaust gas at the center of the exhaust fan 300 is exhausted from the louver 303, but the exhaust gas at the upper portion is guided to the first air passage D 1, as shown by the arrow 302. The exhaust gas is blown out of the second discharge port 51 and toward the FD discharge tray 20, and the lower exhaust gas is guided to the second air path D 2, and is discharged outside the first discharge port 50 and the FU as shown by an arrow 305. It is blown out toward the discharge tray 21.

With the above configuration,
One exhaust fan 300 exhausts the inside of the apparatus main body, FD
The air is blown out to the tray 20 and the FU tray 21, so that the discharged sheets can be prevented from sticking together without increasing the cost and the size of the apparatus.

For example, when the amount of air in the first air passage D1 is small, the air blowout can be balanced by installing the exhaust fan 300 slightly inclined upward as shown in FIG.

The high-speed image forming apparatus has been described above as an example. However, the present invention is not limited to this, and a similar effect can be obtained in a color image forming apparatus using a toner that softens at a relatively low temperature. Can do things.

[0056]

As described above, according to the present invention, the sheets discharged from the plurality of discharge ports and the sheets discharged to the plurality of sheet stacking units are cooled by the air blown out by the common cooling means. This can prevent the discharged sheet from sticking without increasing the cost and increasing the size of the apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a paper discharge unit of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view of an image forming apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of a paper discharge unit of the image forming apparatus.

FIG. 4 is a diagram illustrating a configuration of a paper discharge unit of an image forming apparatus according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a schematic configuration of a laser printer as an example of a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Process cartridge 12 Transfer material 18 Fixing device 19 Flapper 20 FD (face down) tray 21 FU (face up) tray 30 Laser printer 31 Main unit 50 First discharge port 51 Second discharge port 106 Paper cooling fan 111 Top cover 112 Side Cover 113 Duct member 202 Exhaust fan 204 Inner guide 300 Exhaust fan 310 First duct member 311 Second duct member D1 First air path D2 Second air path D3 Third air path

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H033 BA10 BA29 2H072 CB01 CB06 FA01 FB01 FB06 HB00 3F054 AA01 AC01 BA01 BB24 BF08 BF22 DA11

Claims (7)

[Claims] An image forming apparatus configured to discharge a sheet on which the toner image is fixed to a plurality of sheet stacking units by heating by a fixing unit after the toner image is transferred; A plurality of outlets for discharging the sheet on which the toner image is fixed to the plurality of sheet stacking units; and a sheet discharged from the plurality of outlets or a sheet discharged to the plurality of sheet stacking units. An image forming apparatus comprising: a common cooling unit that blows air to cool the sheet. 2. The common cooling means includes a blower fan for sucking outside air into the apparatus main body, and the outside air sucked by the blower fan positioned outside the plurality of outlets or below the outlets, respectively. The image forming apparatus according to claim 1, further comprising: a duct member that forms an air passage that blows out toward the sheet stacking section. 3. The common cooling means includes: an exhaust fan for exhausting air in the apparatus main body to the outside; and a part of air in the apparatus main body exhausted by the exhaust fan to the outside of the plurality of outlets. 2. The image forming apparatus according to claim 1, further comprising: a duct member that forms an air passage that blows out toward the sheet stacking portion positioned below the discharge port. 4. The image forming apparatus according to claim 3, wherein the outside air is sucked at the time of the exhaust, and the air inside the apparatus main body is discharged to the outside together with the outside air. 5. The common cooling means includes a blower fan for sucking outside air into the apparatus main body, and the outside air sucked by the blower fan being located outside the plurality of outlets or below the outlets, respectively. A duct member that forms an air passage that blows out toward the sheet stacking unit; an exhaust fan that exhausts air inside the apparatus main body to the outside; and a part of air inside the apparatus main body that is exhausted by the exhaust fan. 2. The apparatus according to claim 1, further comprising: a duct member that forms another air path that blows out toward the sheet stacking portion located outside or below the plurality of discharge ports. Image forming device. 6. The image forming apparatus according to claim 5, wherein the exhaust fan is provided on both sides of the blower fan, and the other air path is provided on both sides of the air path. 7. A switching means for selectively switching a discharge port for discharging a sheet, and a conveyance path for guiding a sheet from the switching means to one discharge port, wherein the common cooling means includes a blower fan, the blower A duct member for forming an air flow path for blowing an air flow formed by a fan toward the sheet stacking portion located outside or below the plurality of discharge ports, respectively, wherein the air path is 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed between the road and a cover of the apparatus main body.