JPH11139680A - Paper sheet cooler for electrophotography device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cool a paper sheet according to change of a paper sheet size or a paper sheet ream weight by providing the duct blast ports of respective paper sheet coolers opposite to each other on both sides corresponding to the paper sheet length of paper sheets for accumulation piled on a table, and supplying cooling wind from the respective duct blast ports along the paper sheet width direction. SOLUTION: The duct blast port 15 of a first paper sheet cooler is arranged on the center part in the paper sheet lengthwise direction, and connected to a blower 16. The duct blast port 17 of a second paper sheet cooling device is arranged on the opposite side, and connected to a blower 18. By this constitution, cooling wind sent from the duct blast ports 15, 17 is always blown against paper sheets 5 in the horizontal direction on the upper face of the folded paper sheets 5 detected by optical sensors 14. Hereby, a proper quantity of the whole upper faces of the paper sheets 5 folded on a table 10 are whirled up, and cavities are formed between the piled up paper sheets. The cooling wind cools the paper sheets 5 while flowings in the cavities, and hot wind is discharged outside the machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet cooling device for an electrophotographic apparatus.

[0002]

2. Description of the Related Art A fixing device for applying at least a heating action to a print sheet holding a toner image to fix the toner image on the print sheet, and a print sheet sent from the fixing device is folded and stacked and held on a table. An electrophotographic apparatus having a sheet folding device that performs printing and a sheet cooling device that supplies cooling air to print paper sent from a fixing device is known from, for example, Japanese Patent Application Laid-Open No. 270068/1990.

[0003]

SUMMARY OF THE INVENTION Here, Japanese Patent Laid-Open No. 1-2
In the configuration of the sheet cooling device disclosed in Japanese Patent No. 70068, the sheet cooling device is provided so as to face only one side corresponding to the sheet length of the stacked sheets stacked on the table, and the duct air outlet of the sheet cooling device is provided. Since the configuration is such that the cooling air from the sheet is supplied along the width direction of the deposited paper, there are the following problems due to differences in the paper size and the continuous paper amount.

That is, when a sheet having a short length in the sheet width direction is used, the distance from the duct ventilation port to the side of the stacked paper is large, so that the cooling air blown out from the duct ventilation port is diffused. However, since the cooling air cannot be supplied to the predetermined position, the temperature of the sheet on the side of the duct outlet decreases, but the temperature of the sheet on the opposite side remains high. As a result, the sheet is heated and fixed on the printing sheet. When the toners overlap each other, the paper temperature may be higher than the melting point of the toner, and toner fusion may occur.

[0005] Further, in the case of using a long sheet in the sheet width direction, even if the cooling air blown out from the duct blowing port is supplied between the sheets, it is necessary to separate the overlapped sheets by the own weight of the sheet. And the cooling air cannot be supplied along the width direction of the paper, and in this case, the paper temperature on the side opposite to the duct ventilation port remains high,
In the same manner as described above, toner fusion sometimes occurred.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to provide a sheet cooling device for an electrophotographic apparatus capable of efficiently cooling a sheet in accordance with a change in a sheet size or a continuous paper amount.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device for applying at least a heating effect to a printing sheet holding a toner image to fix the toner image on the printing sheet, and a printing sheet sent from the fixing device. And a sheet cooling device for supplying cooling air to the print sheet sent from the fixing device, and a sheet cooling device for stacking and holding the sheet on the table. On both sides corresponding to the sheet length of the deposited paper, duct air vents of the sheet cooling device are provided so as to face each other, and cooling air from each duct air vent is supplied along the paper width direction of the stacked paper. Achieved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First, the overall configuration of the electrophotographic apparatus will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a photosensitive drum. The photosensitive drum 1 starts rotating based on a printing operation start signal from the controller, rotates at a speed corresponding to the printing speed of the electrophotographic apparatus, and continues rotating until the printing operation ends. When the photosensitive drum 1 starts rotating, a high voltage is applied to the corona charger 2 and the photosensitive drum 1
For example, a positive charge is uniformly charged on the surface. A laser beam output from a light source 3 composed of a semiconductor laser, a light emitting diode, or the like is irradiated while scanning the photosensitive drum 1 through a rotating polygon mirror and an fθ lens (not shown).

When character data and graphic data converted into a dot image are sent from a controller to the electrophotographic apparatus as a laser beam on / off signal, a portion where the surface of the photosensitive drum 1 is irradiated with the laser beam and a portion where the laser beam is not irradiated are exposed. It is formed. When the portion of the photosensitive drum 1 where the charge has disappeared due to the irradiation of the laser beam reaches a position facing the developing device 4, the positively charged toner is attracted by static electricity and a toner image is formed on the photosensitive drum 1. .

The paper 5 is transported by a paper transport tractor (not shown) in synchronization with the timing at which the print data formed on the photosensitive drum 1 reaches the transfer position. The toner image formed on the photosensitive drum 1 is sucked onto the paper 5 by the action of a transfer unit 6 that applies a charge of the opposite polarity to the toner image to the back side of the paper 5.

In this way, the sheet 5 set in the sheet hopper 7 is conveyed by the above-mentioned sheet conveying tractor, and is conveyed to the fixing device 8 via the transfer unit 6. The sheet 5 that has reached the fixing device 8 is nipped and conveyed while being heated and pressed by a nip formed by a pair of fixing rollers including, for example, a heating roller 8a and a pressure roller 8b, so that the toner image is fused and fixed to the sheet 5. . Heating roller 8
a and the paper 5 sent out by the pressure roller 8b
The stacker table 10
While being sent out to the side, it is alternately folded along the perforations by the swinging operation of the swing fins 11, and is further stacked on the stacker table 10 while being folded by the moving paddle 12. The area of the photosensitive drum 1 that has passed the transfer position is cleaned by the cleaning device 13 and is prepared for the next printing operation.

When a certain amount of printing paper 5 is accumulated on the stacker table 10, the optical sensor 14 detects the printing paper 5 on the stacker table 10 and lowers the stacker table 10 by a certain amount. The printing paper 5 having substantially the same height as the optical sensor 8 and
A duct air outlet 15 of the first sheet cooling device is arranged at the center of the sheet length direction, and is connected to an air blower 16. On the other hand, on the side opposite to the first sheet cooling device, a duct air outlet 17 of the second sheet cooling device is arranged corresponding to the end position of the minimum sheet length, and is connected to the blower 18. Further, at a position adjacent to the duct air outlet 17 and opposed to the duct air outlet 15 of the first sheet cooling device, a fan 19 for discharging air from the duct air outlet 15 to the outside of the apparatus is arranged.

According to the above configuration, the duct air outlets 15, 1
The cooling air sent out from 7 always blows the paper 5 folded upper surface detected by the optical sensor 14 on the paper 5 in the horizontal direction. Therefore, the entire upper surface of the sheet 5 folded on the table 10 rises up by an appropriate amount to form a cavity between the overlapping sheets, and the cooling air from the duct blowing ports 15 and 17 cools the sheet 5 while flowing through the cavity. The fan 19 discharges warm air to the outside of the machine. Here, the cooling air from the duct blowing port 17 is
, And cools the sheet portion on the side of the duct blowing port 17.

[0014]

As described above, according to the present invention, it is possible to provide a sheet cooling apparatus of an electrophotographic apparatus capable of efficiently cooling a sheet according to a change in a sheet size or a continuous paper amount. Can be reliably prevented from printing trouble.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of an electrophotographic apparatus to which the present invention is applied.

FIG. 2 is a side view in the direction of arrow A in FIG. 1;

FIG. 3 is a plan view taken in the direction of arrow B in FIG. 1;

[Explanation of symbols]

Reference numeral 5: printing paper, 10: stacker table, 14: optical sensor, 15, 17: duct blowing port, 16, 18, blower, 19: fan.

Claims (4)

[Claims] A fixing device that applies at least a heating effect to the printing paper holding the toner image and fixes the toner image on the printing paper; and a printing paper fed from the fixing device is folded and stacked and held on a table. A sheet folding device for an electrophotographic apparatus, comprising: a sheet folding device to be cooled; and a sheet cooling device for supplying a cooling air to the printing sheet sent from the fixing device. The sheet cooling device corresponds to a sheet length of the stacked sheets stacked on the table. Paper ducts of a sheet cooling device are provided on both sides facing each other, and cooling air from each duct ventilation duct is supplied along the sheet width direction of the deposited sheet. Cooling system. 2. The paper for an electrophotographic apparatus according to claim 1, wherein the air flow from one of the paper cooling devices is set to be less than half of the air flow from the other paper cooling device. Cooling system. 3. The paper cooling device according to claim 1, wherein a duct air vent of one paper cooling device and a duct air vent of the other paper cooling device are vertically displaced from each other. A sheet cooling device for the electrophotographic apparatus according to the above. 4. An electronic device according to claim 1, wherein said sheet cooling device is provided with a duct vent of one of said sheet cooling devices so as to be movable in accordance with the length of said printing paper. Paper cooling device for photographic equipment.