JPH03129378A - Electrostatic printer - Google Patents

Abstract

PURPOSE:To eliminate such toner stick that toner once stuck to one sheet again sticks to another sheet and to achieve miniaturization of a printer and the stable traveling of sheet by providing a nozzle blowing compressed air toward the sheet after fixing of toner. CONSTITUTION:The air compressed by a compressor is led to a hose 3, and gets to a nozzle 2. The air getting to the nozzle 2 jets out of plural air ports 4 juxtaposed on the nozzle 2 and is blown toward the sheets 1. The air pressure separates the sheets 1. Simultaneously, the compressed air blown out of the nozzle 2 is subjected to adiabatic expansion and decreases in temperature until it reaches atmospheric pressure. Consequently, the cold air cools the sheets 1. To prevent the accumulating state where the sheets 1 are accumulated from being disturbed, the air pressure of the compressed air blown out of the nozzle 2 is within a range of 0.5 kg/cm<2> to 2.5 kg/cm<2> in terms of gauge pressure, and intermittent blowing of the compressed air is effective. Thus, the sticking of tonner is eliminated, and simultaneously the miniaturization of a printer and paper's stable travel are achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in an electrostatic printing machine equipped with a stacker for stacking sheets after toner fixation.

[Conventional technology]

In D-type printing, toner as a latent image carried on the surface of a photoreceptor is transferred to paper, and the toner is further melted and fixed (fixed) to the paper by heat to form a printed matter.

By the way, recently, there has been an increasing need to expand the printing capacity (printing amount per unit time) of the LLI electric printing press.

Therefore, #one of the factors that expands the printing capacity of electric printing machines
One way is to increase the toner fixing speed, but since this toner fixing speed is greatly affected by the temperature rise value of the toner itself, conventionally, the heating capacity of the toner fixing device has generally been increased to meet this need. I try to do that.

However, heating exceeding the limit for toner fixation on paper causes excessive deformation of the paper (due to the moisture content in the paper being reduced by heating), which causes stable running of the paper, This has an adverse effect on printing on the back side, and is a cause of hindering the speeding up of electrostatic printing machines.

The above-mentioned problem can be solved to some extent by using toner with a low melting temperature, but according to this, when sheets of paper after toner fixation are stacked (stacked), the temperature of the paper has not yet decreased and Once stuck toner sticks to another sheet of paper, or toner stuck to different sheets of paper melts together (toner stick), making it difficult to separate the sheets of paper, and if you forcefully pull the toner away from the sheet of paper.
This may cause inconveniences such as falling off.

As a countermeasure against toner stick mentioned above, conventional methods have been adopted to lower the paper temperature after the toner has been fixed. I am trying to install it.

[Problem to be solved by the invention]

However, according to the method of lowering the paper temperature during transport using a cooling fan installed in the front stage of the stacker in the paper transport system, as the paper transport speed increases, the paper cannot be cooled sufficiently. , the paper path length from the toner fixing device to the stacker is set to be sufficiently long, and multiple cooling fans are placed between them. According to this configuration, the electrostatic printing machine is designed to increase the speed of the equipment. The external dimensions of the device inevitably became larger, and this became a bottleneck to miniaturizing the device.

By the way, compared to continuous paper, cut paper has the advantage of omitting paper post-processing (continuous paper requires cutting one sheet at a time), and recently, in order to save costs, cut paper has been cut on both sides. There is a growing need for printing on both sides,
In any case, there is a problem in that if cooling air is applied to the paper while it is being transported from the toner fixing device to the stacker, the running of the paper will be disturbed and stable running will be impaired.

The purpose of the present invention is to prevent the occurrence of problems such as when the toner fixing speed is increased to improve printing performance, toner that has adhered to another sheet of paper adheres to another sheet of paper, or that toner that has adhered to different sheets of paper melts together. An object of the present invention is to provide an improved electrostatic printing machine that can not only eliminate the so-called toner stick, but also achieve miniaturization of the device and stable running of paper at the same time.

[Means to solve the problem]

The above object is achieved by providing an electrostatic printing machine with a stacker for stacking sheets after toner fixation, and a nozzle for blowing compressed air onto the sheets after toner fixation.

[Effect]

According to the present invention having the above configuration, even when the toner fixing speed is increased in order to improve the printing performance of the electrostatic printing machine, the cooling means for the toner melted and fixed on the paper is not controlled by the stacker. It is provided on the side, and as in the past,
Compared to the case where the paper running path from the toner fixing device to the stacker is sufficiently long and multiple cooling fans are installed in between, there is no need to increase the external dimensions of the electrostatic printing machine, and the equipment can be made smaller. Can be done.

Further, according to the present invention having the above configuration, there is no need to provide a cooling fan in the middle of the paper transport path from the toner fixing device to the stacker, so unlike the conventional case, there is no need to provide a cooling fan in the middle of the paper transport path. At the same time, it is possible to solve the problem caused by the provision of the paper, that is, when the cooling air is applied to the paper during conveyance, the paper travel is disturbed and stable running is impaired.

〔Example〕

Hereinafter, the invention will be explained based on illustrated embodiments. FIG. 1 is a perspective view of a state in which the paper after toner fixation is separated and cooled by the stacker provided in the printing machine of the invention, and FIG. FIG. 2 is a longitudinal cross-sectional view of FIG. 1;

In FIGS. 1 and 2, 1 is the paper stacked on the stacker, 2 is the nozzle provided near the side edge of the paper 1,
3 indicates a hose connected to the nozzle 2, and air compressed by a compressor (not shown) is connected to the hose 3.
The air that reached nozzle 2 was guided by
Blows out from a large number of air holes 4 arranged in parallel in the nozzle 2,
It is sprayed onto paper 1.

Due to this air pressure, the paper 1 is separated as shown in FIG. 2, and at the same time, the compressed air blown out from the nozzle 2 expands adiabatically and its temperature decreases while reaching atmospheric pressure. Therefore, this cold air cools the paper l. In addition, in order not to disturb the stacking state of the sheets 1 stacked on the stacker, the air pressure of the compressed air blown out from the nozzle 2 should be set at a gauge pressure of 0.5 kg/aJ to 2.5 kg.
Experiments have shown that it is effective to set the compressed air within the range of /J and blow out the compressed air intermittently. Also,
When a large number of sheets of printed paper are continuously stacked on the stacker, the nozzle 2 is raised or the paper vertical mechanism (not shown) is lowered to ensure that the newly stacked sheets are always stacked on the stacker. There is no need to explain again that it is a cooling device.

However, as is clear from the description of the illustrated embodiment, according to the present invention, even when the toner fixing speed is increased in order to improve the printing capacity of an electrostatic printing machine, the toner is fused and fixed on the paper l. The cooling means for the toner is installed on the stacker side, and is quieter than the conventional case where the paper path from the toner fixing device to the stacker is sufficiently long and multiple cooling fans are installed between them. There is no need to increase the external dimensions of the electric printing press, and it is possible to downsize one piece of equipment.

Further, according to the present invention having the above configuration, there is no need to provide a cooling fan in the middle of the paper transport path from the toner fixing device to the stacker, so unlike the conventional case, there is no need to provide a cooling fan in the middle of the paper transport path. At the same time, it is possible to solve the problem caused by the provision of the paper, that is, when the cooling air is applied to the paper during conveyance, the paper travel is disturbed and stable running is impaired.

Note that in the present invention, the sheets 1 located below the nozzle 2 where the separation effect by compressed air has disappeared come into contact with each other, but the sheets 1 located below the nozzle 2 have already been sufficiently cooled. Therefore, the aforementioned toner stick does not occur.

By the way, in the illustrated embodiment, the nozzle 2 is connected to the paper 1.
Although the case where the 288 sides are arranged facing each other is illustrated as an example, the present invention is not limited to this only.
For example, even if the number of nozzles 2 is one or three or more,
Basically, the same effects as the illustrated embodiment can be achieved.

〔Effect of the invention〕

The present invention is as described above, and as is clear from the description of the illustrated embodiments, according to the present invention, when the toner fixing speed is increased in order to improve the printing ability, the fixed toner is transferred to another layer. This occurs when toner that adheres to paper or adheres to different papers melts together. Not only can so-called toner sticks be eliminated, but also the miniaturization of devices and the stable running of paper can be achieved at the same time. An improved electrostatic printing machine can be obtained.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a perspective view of a state in which the paper after toner fixation is separated and cooled by a stacker provided in the printing press of the present invention, and FIG. 2 is a perspective view of the state shown in FIG. FIG. ■ is paper, 2 is nozzle, 3 is hose, 4 is air hole.

Claims (1)

[Claims] 1. An electrostatic printing machine equipped with a stacker for stacking sheets of paper after the toner has been fixed thereon, the electrostatic printing machine being equipped with a nozzle that blows compressed air onto the paper after the toner has been fixed.