JPS5912468A - Form separating device of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To prevent an error of separation and a transfer defect, by impressing plural kinds of voltage of a destaticization device, and switching them according to the kind of a copying form and inpressing a voltage suitable for the copying form. CONSTITUTION:When the copying form is relatively thick, the 1st button 11 on a console panel is pressed and then he pulse width setting circuit 13 of a switching regulator 12 outputs a pulse having relatively narror width to impress a relatively low voltage to the destaticization device 14. Consequently, the relatively thick form is separated securely. When the transfer form is thin like tracing paper, on the other hand, the 2nd botton 15 is pressed, and then the pulse width setting circuit 16 outputs a pulse with relatively wide width to impress a relatively high voltage to the destaticization device 14. Consequently, even the thin paper is destaticized sufficiently, and an error of separation and a transfer defect are prevented regardless of the kind of the copying form.

Description

[Detailed description of the invention] The present invention relates to a paper peeling device for an electronic copying machine.

FIG. 1 shows a schematic diagram of a conventional electronic copying machine. In this electronic copying machine, the surface of a photoreceptor drum 1 rotating in the direction of the arrow is charged to Φ by a charger (charging roller 1/con) 2, and a light image is exposed to form an electrostatic latent image. Silence! ?
The lfl image is developed with e-charged 1~nom=particles 3C'. The toner image thus obtained is transferred at a predetermined timing onto copy paper 4, which is transported in the direction of the arrow by a transport device (not shown). In this transfer, the copy paper 4 superimposed on the dove image on the photoreceptor drum 1 is charged to ■ by a transfer charger (transfer corotron) 5, and the toner particles 3 are attracted to it by electric attraction force. This is done by After the transfer, the copy paper 4 is neutralized by a static eliminator (upper static eliminator roller 1) 6 and peeled off from the surface of the photoreceptor drum 1. The copy paper 4 after peeling is sent to the fixing device 7, where it is fixed and a copy image is obtained.

By the way, copy paper 4 used in such an electronic copying machine
There are two types of paper: ordinary relatively thick paper and thin paper such as tracing paper. Since the surface electrical resistance of the tracing paper is greater than that of ordinary paper, the electrical attraction force on the photosensitive drum 1 is greater for the former than for the latter. However, the voltage applied to the static eliminator 6 was a certain standard value regardless of the type of copy paper 4. For this reason, when the copy paper 4 is a thin tracing paper, the static eliminator 6 may not be able to remove the static electricity from the copy paper 4 sufficiently, and there is a possibility that a peeling error may occur. 7j) If the paper 4 is a relatively thick ordinary paper, no peeling errors will occur, but since it is heavy and the static electricity is removed by the static eliminator 6, the trailing edge will be exposed to light. This has the disadvantage that it hangs down without being adsorbed to the surface of the body drum 1, and transfer defects tend to occur in this area.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a paper peeling device for an electronic copying machine that does not cause peeling errors or transfer defects regardless of the type of copy paper.

In the present invention, the above-mentioned object is achieved by applying several types of voltage to the static eliminator, switching the voltage according to the type of copy paper, and applying a voltage suitable for each copy paper.

The present invention will be described in detail below with reference to Examples.

FIG. 2 shows a block diagram of the paper peeling device in the first embodiment of the present invention. If the copy paper is ordinary relatively thick paper, the first button 11 provided on the operation panel (not shown) is pressed. Then, the first pulse width setting circuit 13 of the converter type switching regulator 12 outputs a pulse having a predetermined relatively narrow width.

Depending on the width of this output pulse, 1. A converter type switching regulator 14 converts a relatively low high voltage into a static eliminator 1.
4. As a result, the charge removal by the defrost device 14 becomes weaker to some extent than in the conventional example described above. Therefore, even if the copy paper is relatively thick and heavy, the trailing edge will be attracted to the surface of the photosensitive drum, and no transfer defects will occur in this area. Please note that the copy paper may be relatively thick,
If the peeling is performed reliably by utilizing the stiffness, the voltage applied to the static eliminator 14 may be set to 0.

If the copy paper is thin paper such as tracing paper, do not press the second button 15 on the operation panel.

Accordingly, a predetermined relatively wide pulse is output from the second pulse width setting circuit 16 of the converter type switching regulator 12. Depending on the width of this output pulse, the inverter type switching regulator 12 applies a relatively high voltage to the static eliminator 14. As a result, the static electricity removal by the defrost device 14 becomes stronger to some extent than in the conventional example described above. Therefore, even if the copy paper is a young paper such as tracing paper, the charge is sufficiently removed and no peeling errors occur.

FIG. 3, in which the same parts as those in FIG. A paper detection device 21 detects copy paper sent to the drum.

The paper detection device 21 consists of a light source and an xl-sensor. The light rays from the light source are applied to the copy paper (black), and the transmitted light (or reflected light) is received by the photosensor. If the copy paper is ordinary paper, the light rays will no longer be incident on the photosensor. On the other hand, if it is tracing paper, the amount of incident light decreases.Such detection results are supplied to the paper discrimination circuit 22 as an analog signal.

The paper discrimination circuit 22 compares the signal level of the supplied analog signal with a reference signal level and discriminates whether the copy paper is normal paper or tracing paper. Based on this determination, a signal is supplied to one of the two pulse width setting circuits 13, 16, and an appropriate voltage is applied to the static eliminator 14. Zunarichi automatically discriminates the type of copy paper and applies an appropriate electric current J' suitable for the copy paper to the static eliminator 14 according to the result of this discrimination.

In the above embodiment, two types of voltage are applied to the static eliminator, but the voltage is not limited to this, and it may be possible to use 33 or more types and to be able to handle three or more types of copy paper. .

As explained above, according to the present invention, the voltage applied to the static eliminator is suitable for copy paper! ζ can be removed, so regardless of the type of copying paper, peeling errors and transfer defects can be avoided, and the reliability of paper feeding is improved, and copying errors do not occur.

[Brief explanation of drawings]

Figure 1 shows an example of an electronic copying machine? 2 is a block diagram of a paper stripping device according to the first embodiment of the present invention, and FIG. 3 is a block diagram of a paper peeling device according to the second embodiment of the present invention. 11. 15...Button 12...Converter type switching regulator 13.16...Pulse width setting circuit 14...
・Static eliminator 21 ・・Paper detection device 22 ・・Paper discrimination circuit Application Patent attorney Yamanouchi m1di Fuji Gerox Co., Ltd.

Claims (1)

[Scope of Claims] A static eliminator that removes static electricity from copy paper after it has been superimposed on a toner image on a photosensitive drum and has received the transfer thereof, and several types of static eliminators that are predetermined according to the type of copy paper. 1. A paper peeling device for an electronic copying machine, comprising: a power supply circuit for applying a voltage of U<- to a static eliminator.