JPH0876611A - Transfer device and destaticizer - Google Patents

Abstract

PURPOSE: To eliminate a transfer gap requiring a mechanical precision and further, to form an excellent recorded image on plural recording mediums having a different thickness by making a transfer means made of a conductive film coming into elastic contact with an image carrier with the recording medium. CONSTITUTION: A recorder 7 is provided with a transfer electrode 7a made of the conductive film coming into elastic contact with a photoreceptor drum 1 with the recording medium 6. The developed image 11 formed on the drum 1 is transferred to the recording medium 6 by an electric field for the transfer formed by the transfer electrode 7a. When the recording medium 6 is not passed through, the transfer electrode 7a is stopped in a separated state from the drum 1 by the rotation of a transfer electrode holding member 7b. When the leading edge of the recording medium 6 reaches the gap between the transfer electrode 7a and the drum 1, the film-like transfer electrode 7a is stopped in a contact state with the rear surface of the recording medium 6 by the rotation of the transfer electrode holding member 7b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image recording in which an electrostatic latent image formed on an electrostatic latent image carrier is developed with a developer and the developed image is transferred to a recording medium to record an image. Device or an electrostatic recording device for recording an image by selectively charging a developer uniformly formed on a developer carrier by an ion current and transferring the developer charged to a predetermined polarity onto a recording medium. The present invention relates to a transfer device and a static eliminator used for the above.

[0002]

2. Description of the Related Art Conventionally, the above electrostatic recording apparatus is basically
On the developer carrier, a developer carrier uniformly supporting a thin layer of developer, modulated ion supply means for supplying an ion current modulated according to an image signal toward the developer carrier, And a transfer means for selectively transferring a portion of the uniformly formed developer to which the ion flow is supplied onto the recording medium.

As an electrostatic recording apparatus of this kind, for example,
The one disclosed in Japanese Patent Laid-Open No. 61-209461 is known. FIG. 8 shows the above-mentioned JP-A-61-2946.
1 shows a specific configuration of the electrostatic recording device disclosed in Japanese Patent Publication No. In the figure, reference numeral 101 is a developer carrier that rotates in the direction of the arrow, and reference numeral 102 is the developer carrier 1.
A contact blade abutting 01, a reference numeral 103 is a modulation ion supply means for supplying an ion current modulated according to an image signal, and a reference numeral 104 is a transfer electrode arranged with a predetermined gap from the developer carrying member 101. Is.

In this electrostatic recording apparatus, first, the contact blade 102 thins a layer of the developer 105 on the surface of the developer carrier 101, and then the modulated ion supply means 103 forms an electrostatic latent image according to an image signal. Are formed on the surface of the developer carrying member 101. Then, between the developer carrying member 101 on which the electrostatic latent image corresponding to the image signal is formed and the transfer electrode 104 as described above, only the developer 105 charged to a predetermined polarity is on the transfer electrode 104 side. A transfer electric field that flies to the electrostatic latent image is formed, and the developer 105 corresponding to the electrostatic latent image is transferred to the recording medium 106 passing between the developer carrier 101 and the transfer electrode 104, and the recording medium 1
A visible image corresponding to the image information is formed on 06. Then, the recording medium 106 on which the developed image is transferred is conveyed to the fixing device 107 to fix the visible image, and a series of image forming operations is completed.

[0005]

However, the above-mentioned prior art has the following problems. That is, in the electrostatic recording apparatus configured as described above, brass or SUS itself, or those obtained by coating the surface of these metals with a resistance layer having high hardness is used as the transfer electrode 104. Since the developer 105 is selectively transferred to the recording medium 106 by the transfer electric field formed between the developer carrying member 101 and the developer carrying member 101, there is a gap between the recording medium 106 passing over the transfer electrode 104 and the developer carrying member 101. It is required to form a predetermined gap (hereinafter referred to as a transfer gap). This transfer gap is about 20
The transfer gap is about 100 μm to 100 μm, and the scattering of the developer 105 flying from the developer carrying member 101 side to the recording medium 106 is small, and a good transferred image is obtained on the recording medium 10.
6 can be formed. However, the recording medium 106
If the thickness of the recording medium 106 is constant, there is no problem, but in this type of electrostatic recording device, it is assumed that an image is formed on a thick paper such as a postcard. In such a case, depending on the thickness of the recording medium 106. As a result, the transfer gap fluctuates, so that a good transferred image cannot be formed.

Further, in this type of electrostatic recording apparatus, it is required to maintain the strength of the transfer electric field substantially constant in order to realize stable transfer efficiency. If the value fluctuates, the strength of the transfer electric field naturally changes, so that there is a problem in that it is not possible to always transfer with a constant transfer efficiency.

Such a problem is caused by developing the electrostatic latent image formed on the electrostatic latent image carrier with a developer and transferring the developed image to a recording medium to record an image. Even in an image recording apparatus such as a printing machine, a similar transfer electric field cannot be formed, or when the charge of the recording medium cannot be satisfactorily removed after the transfer is completed, the same phenomenon occurs.

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art, and its object is to develop an electrostatic latent image formed on an electrostatic latent image carrier into a developer. Image is developed by transferring the developed image to a recording medium to record an image, and the developer uniformly formed on the developer carrying member is selectively charged with an ion current to have a predetermined polarity. A transfer device and a static eliminator used in an electrostatic recording device or the like for transferring an electrostatically charged developer to a recording medium to record an image, eliminating a transfer gap requiring mechanical accuracy, Another object of the present invention is to provide a transfer device and a static eliminator capable of forming a good recorded image on a plurality of different recording media.

[0009]

In order to solve the above problems, a transfer device of the present invention is a transfer device for electrostatically transferring a developed image formed on an image carrier onto a recording medium. In the transfer device having, the transfer means is constituted by a conductive film elastically contacting the image carrier via a recording medium, and a predetermined voltage is applied to the conductive film, and the conductive film is In synchronization with the conveyance of the recording medium, it is arranged so as to be switchable between a position that contacts the image carrier and a position that does not contact the image carrier.

Further, the static eliminator of the present invention is a static eliminator having a static eliminator for eliminating static electricity in order to separate the recording medium on which the developed image formed on the image carrier is transferred from the image carrier. The means is composed of a conductive film that elastically contacts the recording medium, and a predetermined voltage is applied to the conductive film, and the conductive film is brought into contact with the recording medium in synchronization with the conveyance of the recording medium. It is arranged to be switchable between a position and a position where it does not contact.

[0011]

According to the present invention, since the pressure from the back surface of the recording medium to the developer carrying member can be reduced, the recording medium can be brought into contact with the image carrying member to perform the transfer. A good toner image can be obtained on the recording medium without deterioration of image quality.

Further, since the conductive film is used as the transfer means, the transfer voltage can be applied without being affected by the thickness of the recording medium due to the flexibility of the film, and a good transferred image can be formed on the recording medium.

Further, by providing a mechanism for rotating and stopping the transfer means in synchronism with the conveyance of the recording medium, the transfer means is not contaminated with toner, so that the back surface of the recording medium is not contaminated and the transfer is performed. A stable and good transferred image can be obtained without being affected by the toner contaminated on the means.

Incidentally, also in the static eliminator of the present invention, the same operation as described above can be obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

FIG. 2 shows an embodiment of an electrophotographic image recording apparatus to which the transfer device according to the present invention is applied.

In the figure, reference numeral 1 is a photosensitive drum, and the photosensitive drum 1 is rotationally driven at a predetermined speed in the direction of the arrow by a driving means (not shown). After the surface of the photosensitive drum 1 is uniformly charged to a predetermined potential by the scorotron 2 for primary charging,
Laser ROS (Raster Output Sca)
image exposure means 3 such as (nner) performs image exposure according to image information to form an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum 1 is developed by the developing device 4 to be visualized. The developed image formed on the photoconductor drum 1 is transferred onto a recording medium 6 supplied from a paper feed tray 5 at a predetermined timing by a transfer device 7 according to an embodiment of the present invention, and then, a photosensitive image is formed. Body drum 1
Separated from the surface of. Then, the recording medium 6 to which the developed image is transferred is conveyed to the fixing device 8, where the developed image is fixed on the recording medium 6 and is ejected outside the apparatus.

The surface of the photosensitive drum 1 after the development image transfer step is completed is cleaned by a cleaning device 9 to remove residual toner and the like, and then neutralized by a neutralization device 10 for the next image recording step. Prepare

By the way, in this embodiment, the transfer means is
The image carrier is composed of a conductive film that elastically contacts the image carrier through the recording medium, applies a predetermined voltage to the conductive film, and synchronizes the conductive film with the transport of the recording medium. It is arranged to be switchable between a position where it contacts the body and a position where it does not contact the body.

That is, the transfer device 7 includes the recording medium 6
The transfer electrode 7a is formed of a conductive film that elastically contacts the photosensitive drum 1 via the transfer electrode 7a. As shown in FIG. 1, the transfer electrode 7a is attached to a rod-shaped transfer electrode holding member 7b made of SUS or the like, which is rotationally driven by a rotational drive means (not shown), and the transfer electrode 7a is attached to the transfer electrode 7a. The holding member 7b has a part of the surface 7b 'formed flat and has a substantially D-shaped cross section. The transfer electrode 7a is made of a conductive film formed in a curved shape having a predetermined radius of curvature, and the transfer electrode 7a is, for example, 50 to 200.
A film obtained by vapor-depositing aluminum on a PET film having a thickness of preferably 75 μm is used. Further, as the transfer electrode 7a, PVdF, fluororesin, or resin such as low resistance polyolefin is used.
The resistivity is set to, for example, 10 ³ Ω · cm or less. Then, even if the recording medium 6 having a different thickness is conveyed between the transfer electrode 7a and the photosensitive drum 1,
The elasticity of the transfer electrode 7a itself elastically deforms the transfer electrode 7a so that the transfer electrode 7a always comes into contact with the recording medium 6 in a good state, and no problem occurs.

Further, the transfer electrode 7a and the photosensitive drum 1
Between the recording medium 6 and the recording medium 6, there is a transfer electric field which attracts the developed image 11 formed on the photosensitive drum 1 and charged to a specific polarity from the photosensitive drum 1 side to the transfer electrode 3 side. The formed and attracted developed image 11 is transferred to the transfer electrode 7
Recording medium 6 passing between a and the surface of the photosensitive drum 1.
Is electrostatically transferred to. As shown in FIG. 1, the transfer power source 12 for applying the transfer voltage to the transfer electrode 7a is controlled by a constant current of about 1 to 5 μA, so that the applied voltage is automatically adjusted. There is. This applied voltage is a DC voltage of 10 with respect to the plain paper 6.
It is set to about 00V.

With the above-mentioned structure, the image recording apparatus according to this embodiment eliminates the transfer gap requiring mechanical accuracy as described below, and further performs good recording on a plurality of recording media having different thicknesses. It is possible to form an image. That is, in the image recording apparatus, as shown in FIG. 2, a developed image 11 corresponding to image information is formed on the surface of the photosensitive drum 1 by a well-known electrophotographic process. The developed image 11 formed on the photosensitive drum 1 is
As shown in FIG. 1, it is transferred onto the recording medium 6 by the transfer electric field formed by the transfer electrode 7a. At this time, the transfer electrode 7a is set to the position shown in FIG.
As shown in FIG. 3, the film-shaped transfer electrode 7 a is stopped by the rotation of the transfer electrode holding member 7 b in a state of being separated from the photosensitive drum 1. Then, the recording medium 6 conveyed from the paper feed tray 6 in synchronization with the rotation of the photosensitive drum 1.
When the front end of the recording medium 6 reaches the gap between the transfer electrode 7a and the photosensitive drum 1, the transfer electrode 7a has a transfer electrode holding member 7b of the transfer electrode holding member 7b, as shown in FIG. The rotation stops the film-shaped transfer electrode 7a in contact with the back surface of the recording medium 6.

In this state, a predetermined transfer voltage is applied to the transfer electrode 7a by the transfer power supply 12 controlled by a constant current. Therefore, between the transfer electrode 3 and the photoconductor drum 1, a developed image 11 formed on the photoconductor drum 1 and charged to a specific polarity is attracted from the photoconductor drum 1 side to the transfer electrode 7a side. Such a transfer electric field is formed across the recording medium 6, and the attracted developed image 11 is electrostatically transferred to the recording medium 6 passing between the transfer electrode 7a and the surface of the photosensitive drum 1. It has become so.

As described above, in the above embodiment, the recording medium 6 is used.
Since the pressure from the back surface of the photosensitive drum 1 can be reduced,
It becomes possible to transfer the recording medium 6 by contacting the photosensitive drum 1, so that a good toner image can be transferred onto the recording medium 6 without causing image deterioration such as toner scattering.

Since a conductive film is used as the transfer electrode 7a, the transfer voltage can be applied without being affected by the thickness of the recording medium 6 due to the flexibility of the film, and a good transferred image can be obtained on the recording medium. 6 is formed.

Further, since the transfer electrode 7a is provided with a mechanism for rotating and stopping the transfer electrode 7a in synchronism with the conveyance of the recording medium 6, the transfer electrode 7a is not contaminated with the toner, so that the back surface of the recording medium 6 is contaminated. In this way, a stable and good transferred image can be obtained without being affected by the contaminated toner on the transfer electrode 7a.

Embodiment 2 FIG. 4 shows another embodiment 2 of the present invention. In this embodiment 2, the transfer device according to the present invention is used for the development uniformly formed on the developer carrying member. It is configured to be applied to an electrostatic recording device that records an image by selectively charging an agent with an ion stream and transferring a developer charged with a predetermined polarity onto a recording medium.

FIG. 4 is a schematic sectional view showing a structural example of an electrostatic recording apparatus according to the second embodiment of the present invention.

This electrostatic recording apparatus is roughly divided into a developer carrier 21 made of an aluminum roll which rotates at a predetermined speed in the arrow direction, and a thin developer carrier on the surface of the developer carrier 21. A developing device 20 for forming a layer, an ion flow control recording head 22 as an electrostatic latent image forming means for forming an electrostatic latent image on the developer carrier 21 according to image information,
It is composed of a transfer device 23 facing the developer carrying member 21.

In the developing device 20, a hopper 24 containing a developer is arranged on the back side of the developing carrier 21, and the other end of the layer forming member 25, one end of which is fixed to the hopper 24, carries the developer. The developer 26 held in contact with the body 21 is continuously and uniformly thinned on the surface of the developer carrier 21 in accordance with the rotation of the developer carrier 21. It is supposed to be done. The layer forming member 25 is
A silicon rubber 28 is adhered to the tip of a stainless steel support 27.
The developer 26 is brought into contact with the developer carrying member 21 with a predetermined pressing force based on the elastic force of 7, and the developer 26 is thinned to a uniform thickness and frictionally charged.

Here, the developer 26 is a non-magnetic one-component developer made of an insulating toner, and the developer carrier 21.
When it is thinned on the surface of, the surface is triboelectrically charged to -10 to -70V. Reference numeral 29 is a transfer voltage source for applying a transfer voltage to the developer carrying member 21, reference numeral 30 is a transport roll for attaching the developer 26 in the hopper 24 to the developer carrying member 21, and reference numeral 31 is the developer carrying member 21. It is a sealing member that seals between the hopper and the hopper.

The ion flow control recording head 22 is also provided.
Is an ion flow supply source 32 that uniformly ejects ions along the longitudinal direction of the developer carrier 21 (a direction perpendicular to the paper surface), and the ion flow ejected from the ion flow supply source 32 based on image information. It is composed of an ion flow modulating means 33 which selectively modulates each pixel, and is arranged so as to spray the modulated ion flow onto the surface of the developer carrying member 21. The ion flow supply source 32 is a conductive chamber 32a made of stainless steel, aluminum or the like, and a corona discharge wire 32b stretched in the conductive chamber 32a. An air flow in which ions generated by corona discharge are introduced into the conductive chamber 32a. It is supposed to be ejected by being guided by. The ion flow modulating means 33 is composed of an insulating substrate 33b such as glass and a plurality of control electrodes 33a arranged on the insulating substrate 33b according to the pixel density, and the insulating substrate 33b serves as the chamber 32a. An ion flow path is formed by projecting above the provided ion ejection port. Further, the control electrode 33a of the ion flow modulating means 33 is connected to a control power supply 34 for controlling ON / OFF of energization of the control electrode 33a according to image information.

In the ion flow control recording head 22 configured as described above, when the control power supply 34 turns on the power supply to the specific control electrode 33a according to the image information, the space between the conductive chamber 32a and the control electrode 33a is changed. An electric field is formed in the chamber 32a, and the ion flow passing through the electric field is generated in the chamber 32a.
Alternatively, since it flows into the control electrode 33a, the ion flow is not ejected from the pixel corresponding to the control electrode 33a in the ON state to the outside, and the ion flow is ejected only from the pixel corresponding to the control electrode 33a in the OFF state as a result. To be done. Therefore,
The ion flow sprayed on the developer carrying member 21 is modulated according to the image information, and the charge amount of the developer 26 in the region where the ion flow is sprayed on the developer carrying member 21 changes to cause electrostatic discharge. A latent image is formed. In the ion flow control recording head 22, the ion flow modulating means 33 is arranged at a distance of 0.02 to 5 mm from the developer carrier 21, and more preferably at a distance of 0.1 to 3 mm. Has been done.

On the other hand, the transfer electrode 23a of the transfer device 23
Is a transfer electrode holding member 2 having a rotating mechanism (not shown).
It is attached to 3b. The transfer electrode 23a is made of a conductive film and preferably has a thickness of 50 to 200 μm.
A 5 μm-thick PET film with aluminum vapor-deposited is used. The developer carrier 21 and the transfer electrode 23
Even if the recording medium 6 having a different thickness is conveyed between the transfer medium 23a and a, no problem occurs due to the elasticity of the transfer electrode 23a itself.

Further, the transfer electrode 23a and the developer carrier 21
A transfer electric field is formed between the recording medium 36 and the recording medium 36 so as to attract the developer 26 charged to a specific potential from the developer carrying member 21 side to the transfer electrode 23a side. The agent 26 is transferred to the recording medium 36 passing between the transfer electrode 23a and the surface of the developer carrier 21. The transfer power supply 35 applied to the transfer electrode 23 is
The applied voltage is automatically adjusted by controlling with a constant current.

Reference numeral 37 is a fixing device, and the recording medium 36 on which the toner image has been transferred is sent to the fixing device 37 and the fixing process of the toner image is performed. Is discharged.

5 and 6 show an embodiment of the transfer electrode mounting member 23b which rotates in the electrostatic recording apparatus of the present invention. In this figure, the transfer electrode mounting member 2
A SUS rod is used as 3b.

With the above construction, the electrostatic recording apparatus according to this embodiment eliminates a transfer gap requiring mechanical accuracy as described below, and is suitable for a plurality of recording media having different thicknesses. It is possible to form a recorded image. That is, in the electrostatic recording apparatus, as shown in FIG. 4, a developed image charged to a predetermined polarity is formed on the surface of the developer carrier 21 in accordance with image information. The developed image of a predetermined polarity formed on the developer carrying member 21 is shown in FIG.
As shown in, the transfer electrode 23a transfers the transfer electrode 23a onto the recording medium 36 by the transfer electric field. At that time, the transfer electrode 23a is
As shown in FIG. 6, the transfer electrode holding member 23b is rotated to stop the film-shaped transfer electrode 23a while being separated from the developer carrying member 21. Then, in order that the timing of the transfer electrode 23a may coincide with that of the recording medium 36 conveyed from a sheet feeding tray (not shown) in synchronism with the rotation of the developer carrying member 21, the tip of the recording medium 36 is the transfer electrode 23a. When the gap with the developer carrying member 21 is reached, as shown in FIG. 5, the transfer electrode holding member 23b is rotated to stop the film-shaped transfer electrode 23a in contact with the back surface of the recording medium 36.

In this state, a predetermined transfer voltage is applied to the transfer electrode 23a by the transfer power supply 35 controlled by a constant current. Therefore, between the transfer electrode 23a and the developer carrying member 21, a developer image formed on the developer carrying member 21 and charged with a specific polarity is formed.
A transfer electric field that attracts the transfer electrode 23a to the transfer electrode 23a side is formed sandwiching the recording medium 36, and the attracted developed image passes between the transfer electrode 23a and the surface of the developer carrying member 21. It is adapted to be electrostatically transferred to the medium 36.

Thus, in the above embodiment, the recording medium 3
Since the pressure from the back surface of 6 to the developer carrying member 21 can be reduced, the recording medium 36 can be brought into contact with the developer carrying member 21 to perform the transfer, which causes image deterioration such as toner scattering. A good toner image without a recording medium 3
6 can be transferred onto.

Since a conductive film is used as the transfer electrode 23a, the flexibility of the film makes the recording medium 3
The transfer voltage can be applied without being affected by the thickness of 6, and a good transferred image is formed on the recording medium 36.

Further, since the transfer electrode 23a is provided with a mechanism for rotating and stopping the transfer electrode 23a in synchronism with the conveyance of the recording medium 36, the transfer electrode 23a is not contaminated, so that the back surface of the recording medium 36 is contaminated. Without transfer electrode 23a
A stable and good transferred image can be obtained without being affected by the toner contaminated on the upper surface.

Third Embodiment FIG. 7 shows a third embodiment of the present invention. In this third embodiment, the same parts as those of the first embodiment will be designated by the same reference numerals and will be described. In a static eliminator having a static eliminator for eliminating static electricity in order to separate the recording medium on which the developed image formed on the image carrier is transferred from the image carrier, the static eliminator is elastically contacted with the recording medium. It is composed of a conductive film, and a predetermined voltage is applied to the conductive film, and the conductive film can be switched between a position in contact with the recording medium and a position in which it does not contact in synchronization with the conveyance of the recording medium. It is configured to be arranged.

That is, in this embodiment, a transfer device composed of a corotron is used as in the conventional case, and the static elimination device 40 is the static elimination electrode 40a and the recording medium 6 is used.
A conductive film that elastically contacts with the conductive film, applies a predetermined voltage to the conductive film, and contacts the conductive film in contact with the recording medium in synchronization with the conveyance of the recording medium 6. It is configured so that it can be switched to a position that does not.

The other structure and operation are the same as those of the first embodiment, and therefore the description thereof will be omitted.

[0046]

According to the present invention having the above-described structure and operation, since the transfer electrode does not apply an excessive pressure to the recording medium, the recording medium and the development carrier can be brought into contact with each other to perform the transfer. This makes it possible to obtain a good transferred image without toner scattering.

Further, due to the elasticity of the transfer electrode itself, a good transfer image can be formed on the recording medium without being affected by the thickness of the recording medium, and recording media of various thicknesses can be handled. .

Further, since the transfer electrode is rotated and stopped in synchronization with the conveyance of the recording medium, it is possible to form a good transferred image without backside contamination.

[Brief description of drawings]

FIG. 1 is a configuration diagram of essential parts showing an embodiment of an image recording apparatus to which a transfer device according to the present invention is applied.

FIG. 2 is a block diagram showing an embodiment of an image recording apparatus to which the transfer device according to the present invention is applied.

FIG. 3 is a configuration diagram showing a main part of a transfer device.

FIG. 4 is a configuration diagram showing an embodiment of an electrostatic recording device to which the transfer device according to the present invention is applied.

FIG. 5 is a configuration diagram showing a main part of a transfer device.

FIG. 6 is a configuration diagram showing a main part of a transfer device.

FIG. 7 is a configuration diagram showing another embodiment of the image recording apparatus to which the charge eliminating apparatus according to the present invention is applied.

FIG. 8 is a block diagram showing another embodiment of the image recording apparatus to which the transfer device according to the present invention is applied.

[Explanation of symbols]

1 photoconductor drum, 6 recording medium, 7 transfer device, 7a
Transfer electrode, 7b Transfer electrode holding member.

Claims (2)

[Claims] 1. A transfer device having a transfer means for electrostatically transferring a developed image formed on an image carrier onto a recording medium, wherein the transfer means is transferred to the image carrier via the recording medium. It is composed of a conductive film that elastically contacts,
While applying a predetermined voltage to the conductive film,
A transfer device, wherein the conductive film is arranged so as to be switchable between a position in contact with the image carrier and a position in which it does not contact in synchronization with the conveyance of the recording medium. 2. A static eliminator having a static eliminator for eliminating static electricity in order to separate the recording medium on which the developed image formed on the image carrier is transferred, from the image carrier.
It is composed of a conductive film that elastically contacts the recording medium, and a predetermined voltage is applied to the conductive film, and the conductive film contacts the position of contact with the recording medium in synchronization with the conveyance of the recording medium. A static eliminator characterized in that it is arranged so that it can be switched to a position that does not.