JP3783930B2 - Paper folding device for electrophotographic printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet folding device of an electrophotographic printing apparatus.
[0002]
[Prior art]
The electrophotographic printing apparatus exposes print data to a photoconductive surface of a photoconductor, generates a potential difference on the surface of the photoconductor, develops a toner that is powder ink, and applies the toner from the surface of the photoconductor to a printing sheet. The toner is transferred and heated by a fixing device to melt the toner and fixed on a printing paper, and the printing paper is folded by a paper folding device. The sheet folding device generally has a sheet cooling fan and a duct for cooling the heat remaining on the sheet heated by the fixing device. When there are several sets of the paper cooling blowers and ducts on one side in the paper width direction, they are arranged in the paper length direction and have the same height, and each blower operates / Stop was controlled.
[0003]
Also, a blower and a duct may be arranged on both sides in the paper width direction, and cooling air from the blowers from both sides blows in parallel with the paper width direction. In the case of air blowing from both sides in the paper width direction, one is used for cooling the main paper and the other is used for auxiliary cooling, and the control of operating / stopping the auxiliary blower according to the continuous amount of paper is not performed.
[0004]
[Problems to be solved by the invention]
In the paper cooling method of the conventional paper folding device, the height of each duct arranged in one set in the paper width direction is the same, and even if control for operating / stopping several blowers is performed, The cooling air height range could not be controlled. In addition, the cooling air from both sides of the paper width direction is parallel to the paper width direction, the cooling air from both sides opposes, the circulation of the cooling air is hindered, and heat is generated in the central portion of the paper width direction. There is a problem that toner on the overlapping printing surface is fused due to lack of cooling. Further, since the auxiliary air is blown regardless of the amount of paper, when using paper with a small amount of paper, the floating state of the paper becomes unstable and JAM may occur.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a paper folding device of an electrophotographic printing apparatus that can prevent toner on overlapping printing surfaces from being welded due to JAM and insufficient cooling regardless of the paper size and the continuous amount.
[0006]
[Means for Solving the Problems]
The above purpose is to arrange the ducts arranged in the paper length direction on one side in the paper width direction at different heights, so that each duct has a portion shared in the height direction, and the other in the paper width direction. This is achieved by directing the auxiliary air duct to be blown more obliquely upward and performing control to operate / stop according to the amount of paper.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. In the embodiment shown in the figure, the printed paper 1 is folded along the perforations of the paper by swinging swing fins 2 and the perforations folded by the T-belt 3 are pressed against the table 4 side. When a certain amount of paper 1 is deposited on the table 4, the upper surface of the paper is detected by the optical sensor 5, and the table 4 is lowered by a certain amount.
[0008]
The sheet 1 is heated by a fixing device (not shown) and is conveyed on the table 4 at a high temperature of about 80 ° C. If the temperature of the sheet 1 is not cooled to 65 ° C. or less, the toner on the overlapping printing surface will be collected. Since the problem of welding occurs, it is necessary to dispose a blower for cooling the paper and a duct.
[0009]
As the position of the sheet cooling duct, the height position with respect to the position of the optical sensor 5 is important. If it is too high, the sheet 1 is too lifted by the cooling air and JAM is generated. If the temperature is too low, the floating of the paper 1 becomes small and the paper temperature does not fall below 65 ° C. In addition, although it is effective to control the air blowing height range by the paper continuous amount, it has a height A range suitable for spraying regardless of the paper continuous amount.
[0010]
It is effective to control the air flow rate to the range A by the continuous paper amount. When a large air amount is blown on a paper having a small continuous paper amount, JAM is generated. For paper with a large amount of paper, the paper temperature will not drop unless the air volume is large. Further, in the case of a sheet having a large sheet continuous amount, increasing the range in the blowing height direction other than the A range increases the sheet cooling effect.
[0011]
In this embodiment, cooling fans and ducts are arranged in consideration of the above, and the fans 6, 7, 8 and ducts 9, 10, 11 are arranged side by side in the sheet length direction at one end in the sheet width direction, Main sheet cooling air is blown in parallel with the sheet width direction, and the heights of the ducts 9, 10, and 11 are different. As height positions of the ducts 9, 10, and 11, the ducts 9 and 11 are common, and the duct 10 is at a high position. The ducts 9 and 11 and the duct 10 are arranged with a shared height range A. Further, the ducts 9, 10, and 11 are symmetric with respect to the center in the paper length direction.
[0012]
As the specific position, the ducts 9 and 11 are arranged at a height of −10 to +20 mm with respect to the detection height of the optical sensor 5, and the duct 10 is −5 with respect to the detection height of the optical sensor 5. It is arranged at a height of ˜25 mm. That is, the A range is in the range of −5 to 20 mm with respect to the optical sensor.
[0013]
Further, each of the blowers 6, 7, and 8 can be controlled to operate / stop, and the amount of cooling air is controlled by the operation / stop of the blower. Specifically, the operation / stop in this embodiment is performed as follows by dividing the paper continuous amount into three types of 72-180 kg paper, 71-51 kg paper, and 30-50 kg paper. From 72k to 180kg paper-sometimes, the fans 6, 7, 8 are operated to cool the paper. When the paper is 71 to 51 kg, the fans 6 and 8 are operated to cool the paper. When 30 to 50 kg paper is used, the blower 7 is operated to cool the paper.
[0014]
The amount of air blown from the ducts 9, 10 and 11 is 0.2 to 0.6 m ³ / min, respectively. By adopting the configuration and control, it is possible to control the air volume in the range A based on the continuous paper amount, and also to control the air blowing height range, thereby improving the paper cooling effect without generating JAM. it can. Further, in order to further reduce the occurrence of JAM, the ducts 9, 10, and 11 are symmetrical with respect to the center in the paper length direction, and the balance of the floating of the paper due to air blowing is improved.
[0015]
In order to further improve the cooling effect, it is effective to arrange the auxiliary cooling fan 12 and the duct 13 and the exhaust fan 14 on the opposite side of the ducts 9, 10, and 11 with the paper interposed therebetween. When the air flow 13 is opposite to the air flow in the ducts 9, 10, and 11, heat accumulates in the central portion in the paper width direction, and the paper temperature increases.
[0016]
In this embodiment, in order to prevent heat from being accumulated in the central portion in the paper width direction, the blowing direction of the duct 13 is set obliquely upward (B direction) with respect to the paper width direction. As specific numerical values, the B direction is set to be 15 ° above the paper width direction. If air blown from the blower 12 and the duct 13 is operated regardless of the paper continuous amount, the paper may rise too much with a paper having a small paper continuous amount, resulting in JAM. It can be controlled by the amount.
[0017]
As a specific control, when the paper is 51 to 180 kg, the blower 12 is operated to cool the paper. When 30-50 kg paper is used, the blower 12 is stopped to cool the paper. In the present embodiment, the position of the duct 10 is increased as the height position of the ducts 9, 10, and 11, but the position of the duct 10 can be decreased.
[0018]
In this embodiment, the operation / stop of the blower 12 is controlled by the continuous amount of paper. However, in the case of a paper having a narrow paper width, the paper temperature can be lowered by only one air flow in the paper width direction. It is also possible to control the operation / stop.
[0019]
【The invention's effect】
According to the present invention, several ducts arranged in the paper length direction on one side in the paper width direction are arranged at different heights, and each duct has a position having a portion shared in the height direction, By controlling the operation / stop of the blower, it is possible to control the blowing height based on the continuous amount of paper, and the optimum blowing height common to each continuous amount of paper (the shared height portion of each duct) It is also possible to control the amount of air flow to (), so that it is possible to blow air at the optimum position and air amount with various papers, and it is possible to prevent toner on the overlapping printing surface from being welded due to the occurrence of JAM and insufficient cooling.
[0020]
Further, by directing the auxiliary air duct that blows from the other side in the paper width direction obliquely upward, it is possible to prevent hot air from being trapped in the central portion in the paper width direction, and efficient paper cooling can be achieved.
[0021]
Further, by controlling the operation / stop of the auxiliary air blower, extra air is blown to the paper that has a small amount of paper and can be sufficiently cooled by only one air blow in the paper width direction. JAM can be reduced.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of the present invention.
FIG. 2 is a right side view showing an embodiment of the present invention.
FIG. 3 is a left side view showing an embodiment of the present invention.
FIG. 4 is a perspective view showing a position of a main air duct of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Paper, 2 ... Swing fin, 3 ... T belt, 4 ... Table, 5 ... Optical sensor, 6 ... Blower, 7 ... Blower, 8 ... Blower, 9 ... Duct, 10 ... Duct, 11 ... Duct, 12 ... Blower, 13 ... duct, 14 ... blower.

Claims (4)

Folding perforated continuous printing paper on which toner is heat-fixed is alternately folded upside down, and includes a table on which the folded paper is deposited and a sensor for detecting the top surface of the paper deposited on the table, In the sheet folding device of the electrophotographic printing apparatus in which the table is lowered by a certain amount by detection of the sensor, the fan has several sets of fans and ducts for cooling the sheets, and the fans and ducts are arranged on both sides in the sheet width direction. And a paper cooling structure in which main paper cooling air is blown from one side in the paper width direction and auxiliary cooling air is blown from the other, and several ducts of the main paper cooling air are arranged in the paper length direction. A sheet folding device of an electrophotographic printing apparatus, characterized in that it is arranged, has different blowing heights, and has a shared blowing height portion. The main air flow is performed by three air blowers and ducts, and the duct height range in the center is −5 to +25 mm and the ducts on both sides are −10 to +20 mm with respect to the sensor height for detecting the upper surface of the paper. The sheet folding device of an electrophotographic printer according to claim 1. 2. The paper folding apparatus of an electrophotographic printing apparatus according to claim 1, wherein the auxiliary cooling duct is directed obliquely upward with respect to the paper width direction. 2. The paper folding device of an electrophotographic printing apparatus according to claim 1, wherein the operation / stop of the air blowing from the three main air ducts and the auxiliary cooling duct is controlled by a paper continuous amount.

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