JP2002082591A - Sheet ejecting device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of image quality such as the adhesion of ejected paper by efficiently cooling carried sheet material without impairing carrying ability in an image forming device. SOLUTION: This image forming device is provided with a sheet material cooling means disposed on a more downstream side in a sheet material carrying direction than an external paper ejecting roller 116 ejecting the sheet material P to the outside of a device main body and cooling the sheet material P ejected to the outside of the device main body. In the device, the sheet material cooling means is constituted of an external paper ejecting guide 130 disposed on a more downstream side in the sheet material carrying direction than the roller 116 and guiding the ejected sheet material P to the outside of the device main body, a cooling fan 132 making outside air blow off either or both of front and back surfaces of the sheet material P, an external paper ejection sensor 137 disposed in the vicinity of a more upstream side in the sheet material carrying direction than the roller 116 and detecting a situation just before the leading edge part of the sheet material P rushes in the roller 116 and the trailing edge part of the sheet material P slips through from the roller 116, and a microcomputer 160 controlling the operation of the fan 132 according to the detection signal of the sensor 137.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image on a recording material, and more particularly, to an image forming apparatus having a cooling means for cooling a sheet material with a formed image when discharging the sheet material.

[0002]

2. Description of the Related Art First, an electrophotographic copying machine as an example of an image forming apparatus will be described with reference to FIG.

In FIG. 8, reference numeral 100 denotes an electrophotographic copying machine main body (hereinafter, referred to as an apparatus main body). The document is placed on platen glass 102. Then, the optical image corresponding to the image information of the document is transferred to a plurality of mirrors M of the optical unit 103.
And the lens Ln, an image is formed on the electrophotographic photosensitive drum 104 via the image memory. 105 is a cassette. Among the recording materials (hereinafter, referred to as “sheet materials”) P loaded on the cassette 105, an appropriate sheet material P is determined based on information input by the user from the operation unit or the size of the document, and sheet material size information of the cassette 105. Choose from Here, the sheet material P is not limited to paper, but may be OHP, for example.
A sheet or the like can be appropriately selected.

Then, one sheet material P conveyed by the paper separating device 105A is conveyed to a registration roller 110 via a conveyance section 109, and the photoconductor drum 104, a developing device, and a transfer device are transferred by the registration roller 110. The sheet is sent to an image forming unit having a charger 111 and the like. The registration roller 110 conveys the rotation of the photosensitive drum 104 and the scanning timing of the optical unit 103 in synchronization. Reference numeral 112 denotes a separation charger. Here, the toner image formed on the photosensitive drum 104 is transferred to the sheet material P by the transfer charger 111. Then, the sheet material P on which the toner image has been transferred is separated from the photosensitive drum 104 by the separation charger 112.

[0005] Thereafter, the sheet material P conveyed by the conveying unit 113 is heated and pressed by a fixing device 114 to fix a toner image on the sheet material. , Passing through the paper discharge reversing unit 115, and
After passing through an external paper discharge sensor 137 for detecting the passage of the sheet material P arranged on the upstream side, the paper P is discharged to the outside of the apparatus main body by the external paper discharge roller 116. In the case of double-sided copying, the sheet is temporarily conveyed to the reversing path 120 via the re-feeding conveyance path 119 under the control of the flapper 118 of the sheet discharge reversing unit 115. Here, the end of the sheet material P passes through the re-feeding conveyance path 119, and is conveyed again into the apparatus by rotating the reversing roller 122 in the reverse direction at a timing when the reversing roller 122 is still nipped. Then, after being conveyed to the registration roller 110 via the double-sided path 121, the sheet is discharged to the outside of the apparatus main body along the same path as in the case of single-sided copying.

[0006]

In order to respond to the recent demand for higher speed, not only the speed of conveying the sheet material is increased but also the sheet material conveyed one by one. The interval (paper interval) tends to become narrower. The sheet material discharged after fixing is
It is very hot. Usually, after fixing, the sheet material
The paper is discharged and stacked from a paper discharge roller to a paper discharge tray or a stacker capable of stacking a large amount. Therefore, for example, when a large amount of high-temperature sheet material is stacked on the stacker in a short time, the toner that has been fixed once is melted by the heat accumulated again, and the sheet material sticks to each other (hereinafter referred to as “discharge”). There is a problem that the quality of the formed image is deteriorated.

In view of the above, there has been proposed a sheet cooling means for cooling a sheet conveyed by external air introduced from outside the image forming apparatus main body. However, such cooling means has a problem that the introduced outside air is taken into the inside of the apparatus main body, so that the fixing roller has a low fixing temperature due to a decrease in the temperature of the fixing roller itself, or the inside of the apparatus main body is easily contaminated by suction of paper dust or dust. there were.

On the other hand, according to FIG. 9, a cooling fan 132 that blows external air directly onto a sheet material without passing through the inside of the apparatus main body to cool the sheet downstream of the external paper discharge roller 116 for discharging the sheet to the outside of the image forming apparatus main body. In addition, there is proposed an apparatus in which an external discharge guide 130 is provided for guiding the sheet material without impairing the conveyance behavior of the sheet material due to the air blowing, and the above-described contamination of the inside of the apparatus main body is prevented. In the figure,
External paper discharge guide 130 arranged downstream of external paper discharge roller 116
Is for reliably conveying the sheet material discharged from the apparatus main body, and is attached to the apparatus main body. The external discharge guide 130 includes an upper surface guide portion 130a and a lower surface guide portion 130b.
In the process of being conveyed to 130, the sheet material suitably guides the sheet material for various properties of the sheet material, such as the entering angle and the curl, and functions to accurately convey the sheet material to the outside of the apparatus main body.

Further, the upper surface guide portion 130 of the outer discharge guide 130
The configuration is such that the extension amount L1 of the line a in the substantially transport direction is longer than the extension amount L2 of the lower surface guide portion 130b (L1> L).
2). As described above, the upper surface guide portion 13 that supports and conveys the upper surface of the sheet material from the region of action of the air wind pressure applied from below.
By keeping 0a away, disturbance in the behavior of the leading end of the sheet material is reduced, and more stable transportability can be realized.

According to FIG. 10, which is a view taken in the direction of arrow A in FIG. 9, slits are formed at predetermined intervals substantially parallel to the sheet material conveying direction in the lower surface guide portion 130b of the outer discharge guide 130.
A plurality of 130c are provided. For this reason, the air discharged again to the outside of the apparatus can blow air over a wide range of the sheet material through the slit 130c.

However, the cooling means is assumed to be provided with a sheet processing apparatus such as a finisher for separating the sheet discharged to the downstream side of the image forming apparatus main body. That is, in an image forming apparatus including a sheet material processing device, since the sheet material is constantly nipped and conveyed by at least one of the conveyance rollers provided on the exit side of the apparatus main body or the entrance side of the sheet material processing device, the sheet material receives an external pressure due to cooling. The transfer force is not impaired. However, in the case where the sheet material discharged from the image forming apparatus alone is cooled by the cooling means, the rear end of the sheet material is pulled out from the outer discharge roller 116 and the air is conveyed only by the inertia force. When the external pressure is applied by the
There was a problem that the sheet material was stuck to 130a and a conveyance failure occurred.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a cooling device for cooling a sheet material, which is capable of reducing internal contamination of an image forming apparatus and a reduction in fixing temperature. To provide an image forming apparatus capable of efficiently cooling a sheet material discharged at a high temperature, preventing discharge bonding, and forming a high-quality image without affecting the internal properties of the sheet material. is there. It is still another object of the present invention to provide an image forming apparatus capable of obtaining good cooling properties without impairing transportability by the cooling means.

[0013]

A typical structure of the present invention for achieving the above object is to dispose a sheet material to the outside of the apparatus main body and to be disposed downstream of the sheet main body in the sheet material conveying direction. In an image forming apparatus having a sheet material cooling unit that cools a sheet material discharged to the outside, the sheet material cooling unit is disposed downstream of the discharge unit in a sheet conveying direction, and is configured to output the discharged sheet material. Guide means for guiding the outside of the main body, and blowing means for blowing outside air to either one or both surfaces of the sheet material,
Detecting means disposed closer to the upstream side of the sheet material transport direction than the discharging means, detecting the rush of the leading end of the sheet material into the discharging means, and immediately before the trailing end of the sheet material comes off from the discharging means, And control means for controlling the operation of the blowing means in accordance with the detection signal of the detecting means.

According to the above construction, by controlling the sheet material cooling means in accordance with the detection signal of the detection means for detecting the passage of the sheet material, the conveyed sheet material can be efficiently transported without impairing the transportability. It becomes possible to cool it.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However,
The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention thereto unless otherwise specified.

The schematic configuration of the image forming apparatus excluding the configuration around the sheet material discharge section is exemplified in the above-described conventional example, and therefore detailed description is omitted here.

[First Embodiment] First, a first embodiment of the present invention will be described with reference to FIGS. As described above, in the state where the sheet material conveyance speed is increased, the sheet interval of the sheet material conveyed one by one is narrow, and the sheet material discharged after fixing is considerably high. However, there is a problem in that a large amount of high-temperature sheet material (output paper) is stacked on the stacker 138 outside the apparatus main body, and the discharge of the sheet material occurs, thereby deteriorating the quality of the formed image. .

Therefore, in the present invention, the sheet material discharged to the outside of the apparatus main body is efficiently cooled without passing through the inside of the apparatus main body using the outside air introduced from the outside of the apparatus main body, and without impairing the transportability. A sheet cooling means capable of being discharged to the outside of the apparatus body is proposed.

As shown in FIGS. 1 and 2, a cooling means as a blowing means disposed downstream of the external discharge roller 116 as a discharge means in the sheet material conveying direction and below the external discharge roller 116. The fan 132 sucks air (outside air) from outside the apparatus main body. Thereafter, the air sucked by the cooling fan 132 is discharged again to the outside of the apparatus main body via the intermediate air duct 133 for guiding the air without passing through the inside of the apparatus main body.

1 and 2 (see FIG. 10), the lower surface guide portion 130b of the outer discharge guide 130 as a guide means is substantially parallel to the sheet conveying direction. A plurality of slits 130c as flow paths are provided at predetermined intervals. For this reason, the air discharged again to the outside of the apparatus main body can blow air over a wide range of the sheet material through the slit 130c.

In FIGS. 1 and 2, the cooling means of this embodiment is such that the operation of the cooling fan 132 is controlled by a microcomputer 160 which is a control means. Further, the microcomputer 160 controls the cooling fan 132 based on a detection signal from an external paper discharge sensor 137 disposed in the vicinity of the upstream side of the external paper discharge roller 116 in the sheet material conveyance direction as a detection unit for detecting the passage of the sheet material. It is configured to issue a control command.

More specifically, as shown in FIG. 1, when the sheet material P is discharged to the outside of the image forming apparatus main body, when the leading end of the sheet material passes through the external discharge sensor 137, When the leading end enters the nip portion of the outer discharge roller 116, the microcomputer 160 issues an operation (operation) command to the cooling fan 132. Further, as shown in FIG. 2, when the rear end of the sheet material passes through the external paper discharge sensor 137, that is, when the rear end of the sheet material
Immediately before exiting from the nip portion 6, the microcomputer 160 issues a stop command to the cooling fan 132.

Therefore, the air discharged from the cooling fan 132 does not pass through the inside of the apparatus as compared with the conventional cooling means using external air (outside air).
It does not cause adverse effects such as a decrease in temperature and contamination in the apparatus main body 100. Also, the rear end of the sheet material is
Since the cooling fan 132 is stopped immediately before passing through the sheet 6, the rear end of the sheet material is pulled out of the outside paper discharge roller 116 and the sheet material is conveyed only by the inertia force. The sheet material is prevented from sticking to the upper surface guide portion 130a of the paper guide 130, and a conveyance failure does not occur.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. In the first embodiment of the present invention, an efficient cooling unit using the external introduction air and the external discharge guide 130 has been proposed. However, as the speed is further increased in the future, it is predicted that it is necessary to further increase the amount of air blown to the sheet material in order to prevent the discharge adhesion. For this reason, the sheet material cooled by the air has an unstable behavior during conveyance due to the wind pressure from below, and a phenomenon in which the leading end of the sheet material that has passed through the external discharge guide 130 is turned up, so that the sheet material to the stacker 138 is turned on. Poor loading may occur.

Further, if the sheet interval is reduced as the speed is further increased in the future, the cooling fan 132 according to the first embodiment will have a lower O.D.
In the N / OFF control, it is predicted that it is difficult to appropriately cool the sheet material because the responsiveness of blowing / stopping the air blown to the sheet material is poor.

Therefore, according to the present invention, as shown in FIGS.
A flapper 139 is provided as wind direction adjusting means for adjusting the wind direction of the air discharged from the air outlet 32. The flapper 139 is rotatable about a rotation shaft 140 between a first duct surface 133a and a second duct surface 133b forming the intermediate air duct 133.

3 and 4, the cooling means of this embodiment is such that the operation of the flapper 139 is controlled by a microcomputer 160 as control means.
Further, the microcomputer 160 detects the passage of the sheet material based on a detection signal from an external paper discharge sensor 137 disposed near the upstream side of the external paper discharge roller 116 in the conveyance direction.
It is configured to issue a control command to 39.

More specifically, as shown in FIG. 3, when the sheet material is discharged to the outside of the image forming apparatus main body, when the leading end of the sheet material passes through the external discharge sensor 137, When the leading end enters the nip portion of the external discharge roller 116, the microcomputer 160 issues an operation command to the flapper 139, and the air discharged from the cooling fan 132 is guided to the external discharge guide 130. , The same flapper 1
39 stops at a position where it contacts the first duct surface 133a.

Further, as shown in FIG. 4, when the rear end portion of the sheet material has passed the external paper discharge sensor 137, that is, immediately before the rear end portion of the sheet material exits the nip portion of the external paper discharge roller 116, The microcomputer 160 issues a command again to the flapper 139, and the flapper 139 is placed on the second duct surface 133b so that the air discharged from the cooling fan 132 is not directly guided to the external discharge guide 130. Stop at the contact position. For this reason, the air discharged from the cooling fan 132 is discharged again to the outside of the image forming apparatus main body by providing an exhaust port on the first duct surface 133a.

Accordingly, the ON / OFF responsiveness of the air blown to the sheet material is improved as compared with the cooling means of the first embodiment, and the control of cooling the sheet material and preventing the sheet material from sticking to the outer discharge guide 130 is performed. It will be easier.

In this embodiment, the means for cooling from below the sheet material has been described. For example, when the air blowing direction is from above the sheet material, the slit 130c of the outer discharge guide 130 is provided. Position and each guide part 13
The relationship between the stretching amounts L1 and L2 of 0a and 130b may be reversed.
That is, the upper surface guide portion 130a has the slit 130c, and the extension amount L2 of the lower surface guide portion 130b is
The same cooling effect and transportability can be ensured by adopting a configuration in which the stretching amount a is longer than L1 (L1 <L2).

Further, in the first and second embodiments described above, the structure in which the outside air is blown to one surface (specifically, the lower surface or the upper surface) of the sheet material is exemplified. As shown in FIG. 5, a cooling means (a cooling fan 132, an intermediate air duct 133, and the like) for blowing outside air to a lower surface of the sheet material so as to blow outside air to both surfaces (front and back surfaces) of the sheet material ), A cooling means (cooling means composed of a cooling fan 135, an intermediate air duct 136, etc.) for blowing outside air onto the upper surface of the sheet material may be provided.

Further, although not shown in FIG. 5, a flapper as a wind direction adjusting means in the above-described second embodiment may be provided in each of the intermediate air ducts.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a size detecting means for detecting the size of the sheet material is provided, and inside the intermediate air duct 133 for guiding outside air blown by the cooling fan 132, based on the detection signal of the size detecting means, the sheet is provided. There is provided a wind width adjusting means for adjusting a wind width in a direction intersecting the sheet material conveying direction of the outside air blown to the material.

[0035] The wind width adjusting means may include the intermediate air duct.
A fin 150 for adjusting the air width of the air discharged from the cooling fan 132, a pinion gear 152 rotationally driven by a microcomputer 160 as control means, and a rack gear 151 transmitted and driven by the pinion gear 152 are provided inside 133.
a. Further, a hole 150b provided in the fin 150 has a shaft portion 151 held on a rack gear 151a.
b, the fins 1
50 is rotatable.

Therefore, based on the detection result of the size detecting sensor 161 as the size detecting means (or information input by the user, etc.), the microcomputer 160 as the control means causes the fin 150 to move to a predetermined size corresponding to the width of the sheet material. By controlling the rotation to the position, the intermediate air duct 13
It is possible to adjust the blowing width (wind width) of the air discharged from the plurality of louvers 153 provided downstream in the wind direction in the third direction.

That is, when a wide sheet material is conveyed, it is rotated to open the fins 150 so that the air flows out over a wide area as shown in FIG. When being conveyed, the fin 150 is controlled to rotate in the closing direction as shown in FIG.

As described above, according to the size of the sheet material,
By adjusting the wind width blown to the sheet material as appropriate using the wind width adjusting means, an efficient and uniform cooling effect can be obtained over the entire surface of the sheet material for each size, thereby preventing discharge adhesion. It is possible to do.

[Other Embodiments] In the above-described embodiment,
Although a copying machine has been exemplified as an image forming apparatus, the present invention is not limited to this.For example, a printer, another image forming apparatus such as a facsimile apparatus, or a transfer conveying belt as a transfer medium carrier, An image forming apparatus may be used in which toner images of respective colors are sequentially superimposed and transferred on a sheet material such as a recording sheet carried on the transfer conveyance belt, and similar effects can be obtained by applying the present invention to the image forming apparatus. Can be obtained.

[0040]

As described above, according to the present invention,
By controlling the sheet material cooling means or the air blowing means in accordance with the detection signal of the detection means for detecting the passage of the sheet material, the conveyed sheet material, without impairing the transportability,
And it becomes possible to cool efficiently.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part schematically showing a schematic configuration around a sheet material discharge unit according to a first embodiment.

FIG. 2 is an explanatory diagram of a main part schematically showing a schematic configuration around a sheet material discharge unit according to the first embodiment;

FIG. 3 is an explanatory diagram of a main part schematically showing a schematic configuration around a sheet material discharging unit according to a second embodiment.

FIG. 4 is a main part explanatory view schematically showing a schematic configuration around a sheet material discharge unit according to a second embodiment.

FIG. 5 is an explanatory diagram of a main part schematically showing a schematic configuration around a sheet material discharge unit according to another embodiment;

FIG. 6 is an explanatory view of a main part schematically showing a schematic configuration around a sheet material discharging unit according to a third embodiment.

FIG. 7 is an explanatory view of a main part schematically showing a schematic configuration around a sheet material discharge unit according to a third embodiment.

FIG. 8 is a schematic configuration diagram illustrating an example of an image forming apparatus.

FIG. 9 is an explanatory diagram around a sheet material discharge unit of the image forming apparatus.

FIG. 10 is an explanatory diagram around a sheet material discharge unit of the image forming apparatus.

[Explanation of symbols]

 P: sheet material 100: apparatus main body 102: platen glass 103: optical unit 104: photosensitive drum 105: cassette 105A: paper feed / separation device 109: transport unit 110: registration roller 111: transfer charger 112: separation charger 114 … Fixing unit 115… Discharge reversing unit 116… External discharge roller 118… Flapper 119… Refeeding conveyance path 120… Reversing path 121… Duplex path 122… Reversing roller 123… Inner discharging roller 130… Outer discharging guide 130a … Top guide part 130b… Bottom guide part 130c… Slit 132… Cooling fan 133… Intermediate air duct 133a… Duct surface 133b… Duct surface 135… Cooling fan 136… Intermediate air duct 137… Outside discharge sensor 138… Stacker 139… Flapper 140… Rotating shaft 150 fin 150a Rotating shaft 150b Hole 151a Rack gear 151b Shaft 152 Pinion gear 153 Louver 160 Microcomputer 161 Size detection sensor

Claims (12)

[Claims] 1. An image forming apparatus, comprising: a sheet cooling unit disposed downstream of a discharge unit for discharging a sheet material to the outside of the apparatus main body in a sheet material conveying direction and cooling the sheet material discharged to the outside of the apparatus main body. The sheet material cooling unit is disposed downstream of the discharge unit in the sheet material conveyance direction,
Guide means for guiding the discharged sheet material to the outside of the apparatus main body; blowing means for blowing outside air to one or both of the front and back surfaces of the sheet material; and upstream of the discharge means in the sheet material transport direction. Detecting means disposed in the vicinity, for detecting the entry of the leading end of the sheet material into the discharging means, and immediately before the trailing end of the sheet material comes off from the discharging means, An image forming apparatus, comprising: a control unit that controls an operation of a blowing unit. 2. The control means, when discharging the sheet material to the outside of the main body of the image forming apparatus, activates the blowing means by detecting the entry of the leading end of the sheet material into the discharge means,
2. The blower according to claim 1, wherein the blower is stopped by a detection immediately before the trailing end of the sheet material comes off from the discharger.
An image forming apparatus according to claim 1. 3. An air duct for guiding the outside air blown by said blowing means is provided inside said air duct with a wind direction adjusting means for adjusting a wind direction according to a detection result of said detecting means. The wind direction is variable to a first air duct for guiding the sheet material and a second air duct for guiding the outside air to the inside or outside of the apparatus body so as not to blow the outside air onto the sheet material. Item 2. The image forming apparatus according to Item 1. 4. The control means forms the first air duct using the wind direction adjusting means by detecting the entry of the leading end of the sheet material into the discharge means, and the rear end of the sheet material from the discharge means. 4. The image forming apparatus according to claim 3, wherein control for forming the second air duct is performed by using the wind direction adjusting unit based on detection immediately before the air duct exits. 5. 5. A sheet detecting device for detecting a size of a sheet material, wherein the sheet material is provided inside an air duct for guiding outside air blown by the blowing means, based on a detection signal of the size detecting means. 5. The image forming apparatus according to claim 1, further comprising a wind width adjusting unit configured to adjust a wind width of the blown outside air in a direction intersecting with a sheet material conveyance direction. 6. 6. A discharging means for discharging the sheet material to the outside of the apparatus main body, a blowing means for blowing air to one or both of the front and back surfaces of the sheet material discharged by the discharging means; A sheet discharging device comprising: a detecting unit configured to detect a sheet material discharged by the unit; and a control unit configured to control an operation of the blowing unit in accordance with a detection signal of the detecting unit. 7. The control means starts the blowing by the blowing means when the detecting means detects the leading end of the sheet material, and stops the blowing by the blowing means when detecting the trailing end of the sheet material. The sheet discharging device according to claim 1. 8. The air blowing means has a wind direction adjusting means for adjusting a wind direction in a direction in which the sheet material is blown and in a direction in which the sheet material is not blown, and the control means controls the wind direction adjusting means in accordance with a detection signal of the detecting means. The sheet discharging apparatus according to claim 6, wherein 9. The control means adjusts a wind direction in a direction to blow the sheet material when the detecting means detects the leading end of the sheet material, and adjusts a wind direction in a direction not to blow when detecting the trailing end of the sheet material. 9. The sheet discharging apparatus according to claim 8, wherein the wind direction adjusting means is controlled as described above. 10. A size detecting means for detecting a size of a sheet material, wherein a wind width of air blown on the sheet material in a direction intersecting with a sheet material conveying direction is adjusted based on a detection signal of the size detecting means. The sheet discharge device according to claim 6, further comprising a wind width adjusting unit. 11. A guide means disposed on the downstream side of the discharge means in the sheet material discharge direction, for guiding the sheet material discharged by the discharge means, and the blowing means for blowing the sheet material on the guide means. A flow path through which air from the air passes is provided.
The sheet discharging device according to any one of claims 1 to 6. 12. The image forming apparatus according to claim 6, wherein an image forming unit that forms an image on the sheet material, and the sheet material on which the image is formed by the image forming unit are discharged.