JPH09146320A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable high-quality image by providing a recording medium cooling means on a downstream side in a recording medium carrying direction with respect to a fixing device and providing a means for lowering the ambient temperature of a stacker. SOLUTION: Air whose temperature is made as low as possible blows off the printing surface of a high-temperature recording medium 6 coming from the fixing device 1 by using a ventilating fan 2 for cooling a recording medium so as to cool toner. Thereafter, the recording medium 6 after printing is cooled by a ventilating fan 4 in the stacker to such an extent that trouble is not caused in a folding mechanism in the stacker 3. Since the cooling effect of the fan 4 is lowered when the ambient temperature in the stacker 3 is high, a fan 5 for discharging the warmed air inside the stacker 3 is set to make the ambient temperature in the stacker 3 as low as possible, whereby a difference between the ambient temperature and the temperature of the recording medium 6 after printing is made large. The ambient temperature in the stacker 3 is made constant without lowering the cooling effect even when consecutive printing is performed, and the toner is prevented from being stuck.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention contains a fixing device for fixing a toner image formed on the recording medium to the recording medium by subjecting the recording medium to at least a heating step, and a recording medium sent from the fixing device. The present invention relates to an image forming apparatus including a stacker.

[0002]

2. Description of the Related Art For example, an image forming apparatus using an electrophotographic system comprises a step of visualizing toner as an image on the surface of a recording medium and a step of fixing the visualized toner image on the recording medium. In the fixing step in which the toner is melted by heating and solidified by cooling, the properties of the toner are used to melt the toner by heating, and then the toner is fused or fixed to the recording body by natural cooling. Hereinafter, a conventional recording medium processing device after printing will be described. In the fixing step, the toner arranged as an image on the surface of the recording medium is heated and pressed at the same time. The toner is melted and deformed by being supplied with two types of energy, that is, thermal energy in the melting nip portion and work by pressure. By this action, the toner is fixed on the recording material. After fixing, the recording medium is fused or fixed to the recording medium by natural cooling, and the recording medium is conveyed to the stack mechanism. In this description, the portion of the recording medium having the stacking mechanism is called a stacker.

[0003]

Conventionally, among recording media, continuous paper having perforations is conveyed and fixed at a high speed,
When the sheets are folded by the sheet folding mechanism to stack the sheets, the natural cooling alone cannot provide sufficient cooling. Therefore, a phenomenon in which the printing surface having toner adheres to the printing surface, that is, a so-called toner stick occurs. Particularly in the case of continuous printing, the ambient temperature in the stacker rises, the cooling effect of the printing surface decreases, and toner sticks are likely to occur. When the toner stick occurs, the toner is peeled off and the image is lost, which is a situation in which the print quality should not be satisfied. Normally, when the printing speed is slow, the recording medium is sufficiently cooled by natural cooling or forced cooling by blowing air, and no toner stick is generated. However, when the printing speed is increased, particularly when continuous printing is performed, sufficient cooling cannot be performed by natural cooling or simple forced cooling by blowing air, which causes a problem of toner sticking.

In this case, in order to solve this problem, measures have been taken to increase the amount of air blown for forced cooling and to secure a conveyance distance of the recording medium for natural cooling. However, if the amount of air blown for forced cooling is increased, the stack mechanism of the recording medium does not work properly, or if the recording medium transport distance for natural cooling is secured, the device becomes large, etc. Such a problem occurs.

An object of the present invention is to provide an image forming apparatus which does not impair the stacking mechanism of recording media even when high-speed continuous printing is performed, does not increase the size of the apparatus, and causes no toner stick.

[0006]

The above-mentioned object is to fix a toner image formed on a recording medium by subjecting the recording medium to at least a heating step, and to fix the toner image on the recording medium, and a recording sent from the fixing device. In an image forming apparatus provided with a stacker for accommodating a medium, a recording medium cooling unit is provided on the downstream side in the recording medium conveyance direction with respect to the fixing device, and the stacker is provided with a unit for lowering the ambient temperature To be achieved.

[0007]

It is possible to provide a recording medium processing device for printing after printing, in which the recording medium in the stacker after printing can be sufficiently cooled even if continuous printing is performed at high speed and a toner stick does not occur, and a stable image is provided. It becomes possible to do.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the figure, 1 is a fixing device, 2 is a blower fan for cooling a recording medium, 3 is a stacker, 4 is a blower fan inside the stacker,
Reference numeral 5 is a fan for discharging the warm air in the stacker, and 6 is a recording medium after printing. In this embodiment, continuous paper having perforations is used as the recording medium. In order to fix the print image on the recording medium, the recording medium is instantaneously heated by the fixing device 1, and the surface of the recording medium and the toner formed on the surface are melted and fixed. Further, when the toner and the recording medium are cooled, the fixing is completed. If the printing speed is fast here, the cooling will be insufficient, so
The recording medium processing device after printing is capable of sufficiently cooling even when the printing speed is fast.

First, the printing surface of the high-temperature recording medium coming out of the fixing device 1 is blown by a blower fan 2 for cooling the recording medium.
Air is applied to the printing surface at the lowest possible temperature to cool the toner. After that, since the recording medium is continuous paper having perforations, the recording medium is folded at the perforations and stacked in the stacker 3 as the recording medium 6 after printing. Even in the stacker 3, the blower fan 4 in the stacker cools the recording medium 6 after printing to such an extent that the folding mechanism is not damaged. Here, if the atmosphere temperature in the stacker 3 is high, the cooling effect of the fan 4 inside the stacker decreases, so a fan 5 for discharging the warm air in the stacker 3 is installed to lower the atmosphere temperature in the stacker 3 as much as possible. Thus, the temperature difference between the ambient temperature and the recording medium 6 after printing is increased. If the room temperature is 30 ° C., the temperature of 80 ° C. of the recording medium 6 of the stacker 3 can be lowered to 65 ° C. in the above configuration. If the room temperature is 20 ° C, the temperature can be 60 ° C or lower. In this way, by increasing the temperature difference between the recording medium 6 and the atmosphere in the stacker, the heat transfer is increased and the cooling effect can be improved. With this configuration, even if continuous printing is performed, the ambient temperature in the stacker 3 can be made constant without lowering the cooling effect, and toner sticking can be prevented.

[0010]

According to the image forming apparatus of the present invention, a toner stick is not generated even when high-speed continuous printing is performed, and a high quality and stable image can be provided.

[Brief description of the drawings]

FIG. 1 is a side elevational view showing the present invention.

[Explanation of symbols]

1 is a fixing device, 2 is a blower fan for cooling the recording medium, 3 is a stacker, 4 is a blower fan in the stacker, 5 is a discharge fan,
Reference numeral 6 indicates a recording medium.

Claims (3)

[Claims] 1. A fixing device for fixing a toner image formed on a recording medium to the recording medium by subjecting the recording medium to at least a heating step, and a stacker for accommodating the recording medium sent from the fixing device. In the image forming apparatus, the recording medium cooling means is provided on the downstream side of the fixing device in the recording medium conveying direction, and the stacker is provided with means for lowering the ambient temperature thereof. 2. The image forming apparatus according to claim 1, wherein the recording medium cooling means is a fan that directly blows air onto the printing surface of the recording medium. 3. The image forming apparatus according to claim 1, wherein the stacker atmosphere temperature lowering means has a fan for blowing air to the printing surface of the recording medium and a fan for discharging the air in the stacker.