JP2007206472A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that transfers a toner image, formed on an image carrier, to a recording medium and discharges the recording medium by a discharger, the image forming apparatus being capable of ensuring discharge so as to separate the recording medium from the image carrier while restraining excessive discharge that may cause disturbance of a toner image, scattering of toner, and hence image noise during the discharge of the recording medium with the toner image transferred thereto, and capable of forming an image in which image noise is thus reduced. <P>SOLUTION: The image forming apparatus PR1 transfers a toner image, formed on an intermediate transfer belt 4 as the image carrier, to a recording medium S by a secondary transfer roller 5, and discharges the recording medium S by a discharger 6A. The discharger 6A discharges the image formation area of the recording medium S by the low discharging capability so as to prevent excessive discharge. On the other hand, the discharger 6A discharges margins around the image formation area of the recording medium S by the discharging capability higher than the low discharging capability. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an electrophotographic method, an electrostatic recording method, or the like, such as a copying machine, a printer, a facsimile machine, or a multifunction machine combining two or more of these, and more specifically, formed on an image carrier. The present invention relates to an image forming apparatus of a type in which a transferred toner image is transferred to a recording medium by a transfer device, and the charge is removed from the recording medium on which the toner image has been transferred, using a discharging device.

  In an electrophotographic image forming apparatus, usually, the surface of an electrostatic latent image carrier such as a photosensitive member is charged to a predetermined potential, and exposure is performed according to an image to be formed in the charged region. A latent image is formed, the electrostatic latent image is developed to form a visible toner image, and the visible toner image is finally transferred to a recording medium and fixed.

  In an electrostatic recording type image forming apparatus, the surface of an electrostatic latent image carrier such as a dielectric for electrostatic recording is charged to a predetermined potential, and electrostatic recording corresponding to an image to be formed in the charged area is performed. To form an electrostatic latent image, develop the electrostatic latent image to form a visible toner image, and finally transfer and fix the visible toner image on a recording medium.

  In any type of image forming apparatus, in a monochrome image forming apparatus, usually, a toner image formed on an electrostatic latent image carrier such as a photoconductor as an image carrier is directly transferred to a recording medium and fixed. Is done. In a color image forming apparatus, generally, a toner image formed on an electrostatic latent image carrier is temporarily transferred to an intermediate transfer member (a kind of image carrier) such as an intermediate transfer belt, and the intermediate transfer member Is secondarily transferred to a recording medium and fixed. In a color image forming apparatus, a recording medium in which a toner image formed on an electrostatic latent image carrier such as a photoconductor as an image carrier is electrostatically supported on a charged recording medium support. There is also an image forming apparatus that is transferred to the camera.

  In any case, an image carrier such as a photosensitive member in a monochrome image forming apparatus, an intermediate transfer member (image carrier) in a color image forming apparatus employing an intermediate transfer member, and a recording medium held on a recording medium support. In an image forming apparatus that directly transfers a toner image from an image carrier such as a photoconductor, the transfer of the toner image from the image carrier such as the image carrier such as the photoconductor to a recording medium is performed using a transfer device.

  Such a transfer device applies a voltage having a polarity opposite to the normal charging polarity of the toner forming the toner image to be transferred to the recording medium, thereby forming a transfer electric field to form an image on the image carrier. The toner image is transferred to a recording medium. Therefore, the recording medium on which the toner image is transferred in this manner is in a state where a charge having a polarity opposite to the normal charging polarity of the toner is applied from the transfer device. It is electrostatically attracted to the body and is difficult to be separated from the image carrier.

  In view of this, it has been practiced that the recording medium to which the toner image has been transferred is neutralized by using a neutralizing device so that the recording medium is easily separated from the image carrier. Such a neutralization device generally includes a neutralization member for neutralizing a recording medium, and a neutralization voltage is applied to the neutralization member. The static elimination voltage may be a voltage having a polarity opposite to that of the transfer voltage applied by the transfer device, that is, a voltage having the same polarity as the normal charging polarity voltage of the toner, or 0 [V] or a ground potential.

Such a static eliminator is described, for example, in JP-A-11-95564. The static eliminator described in the publication can remove electricity from a recording medium, and a transfer memory (subsequent electrostatic latent image) can be transferred to a portion of an image carrier directly facing the transfer device without passing through the recording medium. Even if a transfer memory)) that adversely affects image development occurs, it can be erased. Specifically, it has a plurality of static elimination members arranged to face the image carrier, and the other part corresponding to the part where the recording medium of the image carrier is in contact with the other part The transfer memory can be erased by increasing the amount of discharge with respect to.
JP-A-11-95564

  However, when the charge is removed from the recording medium to which the toner image has been transferred using the static eliminator, the toner image may be disturbed if the static eliminator is too high in order for the recording medium to be easily separated from the image carrier. Excessive static electricity (excessive static electricity) that causes the toner to scatter from the recording medium or to generate image noise due to these. However, if the static elimination capability is set low by increasing the distance between the static elimination member and the recording medium, it becomes difficult to reliably separate the recording medium from the image carrier.

  In the static eliminator described in Japanese Patent Laid-Open No. 11-95564, the static eliminator corresponding to the recording medium is applied with a uniform static eliminator voltage across the entire width direction across the recording medium conveyance direction. This problem cannot be solved because the charge is eliminated in the same way.

  If the recording medium is comparatively strong, such as plain paper, by setting the neutralization capability of the static eliminator to be low, the separation of the recording medium cannot be achieved while suppressing excessive static elimination. However, it is difficult to achieve both suppression of overcharge and separation, and the recording medium is like a thin recording paper or special paper that easily follows the curvature of the image carrier surface. Achieving both suppression of excess static elimination and separation is even more difficult, and one must be sacrificed.

  Accordingly, the present invention provides an image forming apparatus in which a toner image formed on an image carrier is transferred to a recording medium by a transfer device, and the charge is removed from the recording medium to which the toner image has been transferred using a charge eliminating device. When removing electricity from the recording medium on which the image has been transferred using the static eliminator, the toner image transferred to the recording medium is prevented from being disturbed, toner scattering from the toner image, and excessive noise removal that causes image noise. It is another object of the present invention to provide an image forming apparatus that can perform static elimination that enables stable separation of a recording medium from an image carrier and can form an image with reduced image noise.

  In order to solve the above-described problems, the present invention provides an image forming apparatus for transferring a toner image formed on an image carrier onto a recording medium by a transfer device and discharging the toner image from the recording medium onto which the toner image has been transferred. The static eliminator performs static elimination with a low static elimination capability without causing excessive static elimination to the image forming area portion of the recording medium, while the outer ear portion of the image forming area portion of the recording medium. In contrast, the present invention provides an image forming apparatus that is a static eliminator that performs static elimination with a higher static elimination capability than the low static elimination capability.

  Here, “overcharge” with respect to the image forming area portion of the recording medium means that the toner image transferred to the image forming area is disordered, the toner in the toner image is scattered from the recording medium, or further, It is to remove electricity from the recording medium to the extent that noise is generated.

  The “image forming area portion” of the recording medium is a recording medium area portion where image formation is allowed, and may be an area portion of the maximum printing width of the image forming apparatus for the recording medium. It may be an area portion of the print width set in the control.

  The “outer ear portion of the image forming area portion of the recording medium” means the outer side of the image forming area portion in the width direction of the recording medium in the direction transverse to the recording medium conveyance direction, in other words, in the direction transverse to the recording medium conveyance direction. For example, margins on the left and right of the recording medium having a width of about 10 mm to 20 mm, which are generally adopted, can be used as the outer ear.

  According to the image forming apparatus of the present invention, the static eliminator that removes electricity from the recording medium to which the toner image has been transferred is used to remove the charge from the recording medium to which the toner image has been transferred. Since static elimination is performed with a low static elimination capability that does not cause excessive static elimination, disturbance of the toner image transferred to the recording medium, scattering of toner from the toner image, and generation of image noise due to them are suppressed, while the recording is performed. The outer ear portion of the image forming area portion of the medium is neutralized with a higher neutralization capability than the low neutralization capability, so that the recording medium can be stably separated from the image carrier, and accordingly, the image is accordingly increased. An image in which noise is suppressed can be formed.

Specific examples of the static eliminator include the following static eliminators.
(1) First neutralization device A neutralization member that faces the recording medium is provided, and the interval between the portion of the neutralization member that faces the outer ear of the image forming region portion of the recording medium and the recording medium is an image of the recording medium. A static eliminator in which the static eliminator is set to be smaller than a distance between the portion of the static eliminator facing the forming region and the recording medium.

In this static eliminator, it is possible to apply a uniform static elimination voltage to the static elimination member as a whole. Even if a uniform static elimination voltage is applied to the static elimination member as a whole, the distance between the static elimination member portion facing the outer ear of the image formation area portion of the recording medium and the recording medium is equal to the image formation area portion of the recording medium. Is set to be smaller than the distance between the portion of the static elimination member facing the recording medium and the recording medium, so that the static elimination voltage is adjusted to cause excessive static elimination to the image forming area portion of the recording medium. Static electricity can be removed with a low static elimination capability, while the outer ear of the image forming area of the recording medium is neutralized with a higher static elimination capability than the low static elimination capability to stabilize the recording medium from the image carrier. Can be separated.
In addition, in the case of the first static eliminator and other static eliminators to be described later, the “static neutralization voltage” is 0 [V] or a ground potential depending on the situation, and is a voltage other than that. It may be selected appropriately according to the situation.

(2) Second neutralization device A neutralization member that faces the image forming area of the recording medium and a neutralization member that faces the outer ear of the image formation area of the recording medium. A static eliminator which is a type of static eliminator having a higher static eliminability than a static eliminator facing an image forming area.

  In this static eliminator, “a type of static eliminator having a high static eliminator” in the “static eliminator facing the outer ear is a type of static eliminator having a higher static eliminator than the static eliminator facing the image forming region” When the same neutralization voltage as the neutralization voltage applied to the neutralization member facing the image forming area is applied to the neutralization member facing the image forming section, the neutralization per unit length of the neutralization member in the recording medium width direction across the recording medium conveyance direction It is a static elimination member whose capability is higher than that of the static elimination member facing the image forming area.

  The second static elimination device can be used by applying the same static elimination voltage to each static elimination member. Even if the same static elimination voltage is applied to each static elimination member, a static elimination member having a higher neutralization capability than that of the static elimination member facing the image forming area is adopted as the static elimination member facing the outer ear portion. For example, the image forming area portion of the recording medium can be neutralized with a low static eliminating capability that does not cause excessive static elimination, while the outer ear portion of the image forming area portion of the recording medium is subjected to the low charge eliminating. It is possible to stably remove the recording medium from the image carrier by performing the charge removal with a higher charge removal capacity than the capacity.

(3) Third neutralizing device A neutralizing member that faces the image forming area of the recording medium and a neutralizing member that faces the outer ear of the image forming area of the recording medium. A static eliminator that applies a static elimination voltage higher (larger in absolute value) than a static elimination member facing the image forming area.

  According to the third static eliminator, since the static eliminator facing the outer ear is configured to be applied with a higher static voltage than the static eliminator facing the image forming area (large in absolute value), the static eliminator applied to each static eliminator. While adjusting the voltage, etc., the image forming area portion of the recording medium is neutralized with a low static eliminating capability that does not cause excessive static elimination, while the outer ear portion of the image forming area portion of the recording medium is Can perform static elimination with a higher static elimination capability than the low static elimination capability, and can stably separate the recording medium from the image carrier.

(4) Fourth static elimination device, which includes a plurality of types of static elimination members with different static elimination capabilities that are arranged in a direction crossing the conveyance direction of the recording medium and face the recording medium, and at least one of the plural types of static elimination members The neutralization member disposed on the outer ear of the image forming area portion of the recording medium has a higher neutralization capability than the neutralization member disposed on the image forming area portion of the recording medium. A static eliminator capable of adjusting the position according to the width of the image forming area of the recording medium so as to be a member.

  Here, the “static elimination member having different static elimination capability” means the static elimination capability per unit length of the static elimination member in the direction crossing the recording medium conveyance direction (in other words, the recording medium width direction) when the same static elimination voltage is applied. Are different static elimination members.

  According to the fourth static elimination device, when the recording medium used is different in size, for example, an A3 size recording paper may be used or an A4 size recording paper may be used as the recording medium. Therefore, when the width of the image forming area of the recording medium is different, a static eliminating member having a high static eliminating capability is applied to the outer edge of the image forming area according to the width of the image forming area of the recording medium. However, by adjusting the static elimination voltage, etc., the image forming area portion of the recording medium is neutralized with a low static elimination capability that does not cause excessive static elimination, while the outer ear of the image forming area portion of the recording medium is removed. It is possible to stably separate the recording medium from the image carrier by performing static elimination on the part with a higher static elimination capability than the low static elimination capability.

  The plurality of types of static eliminators having different static eliminating capabilities in the fourth static eliminator are, for example, static eliminators having higher static eliminators than the static eliminators facing both sides of the static eliminator having the lowest static eliminator in the direction crossing the recording medium conveyance direction. The members are arranged so as to be positioned, and the neutralization member having a high neutralization capability can be adjusted to face the outer ear of the image forming area of the recording medium according to the width of the image forming area of the recording medium. It may be.

(5) Fifth static elimination device A plurality of static elimination members arranged in a direction crossing the conveyance direction of the recording medium and facing the recording medium are provided, and the recording medium according to the width of the image forming area of the recording medium A static elimination device that applies a higher (absolute value greater) static elimination voltage to the static elimination member facing the outer ear of the image forming area than the static elimination member facing the image forming area.

In the case of the fifth static elimination device, each of the plurality of static elimination members may have the same static elimination capability per unit length of the static elimination member in the recording medium width direction across the recording medium conveyance direction.
In the case of the fifth static eliminator, excessive static electricity is generated in the image forming area portion of the recording medium according to the width of the image forming area of the recording medium by adjusting the static eliminating voltage applied to each static eliminating member. While removing the static electricity with a low static elimination ability that is not allowed to occur, the outer ear portion of the image forming area of the recording medium is neutralized with a higher static elimination ability than the low static elimination ability, and the recording medium is removed from the image carrier. It can be separated stably.

(6) Sixth static elimination device A plurality of static elimination needles are connected in a direction crossing the recording medium conveyance direction and have two static elimination members facing the recording medium, and the width of the image forming area of the recording medium Accordingly, the two static elimination members are moved relative to each other in a direction crossing the conveyance direction of the recording medium, so that the two static elimination members jointly face the outer ear portion of the image forming area of the recording medium. A static eliminator capable of setting the density of the static elimination needle larger than the density of the static elimination needle facing the image forming area.

Here, the “density of the static elimination needle” is, in other words, the number of static elimination needles per unit length in the direction crossing the recording medium conveyance direction.
In the 6th static elimination apparatus, in the part in which the static elimination needle density was set high, static elimination capability became higher than the part in which the static elimination needle density was set lower than it.

  In the sixth static elimination device, according to the width of the image forming area of the recording medium, the density of the static eliminating needle facing the outer ear portion of the image forming area of the recording medium can be set larger than the density of the static eliminating needle facing the image forming area. From the image forming area portion of the recording medium, the density of the neutralization needle is set high for the outer ear portion of the image forming area according to the width of the image forming area of the recording medium, and the neutralizing voltage is adjusted. In this case, the static electricity is removed with a low static elimination capability that does not cause excessive static elimination, while the outer ear portion of the image forming area of the recording medium is neutralized with a higher static elimination capability than the low static elimination capability, and recording is performed. The medium can be stably separated from the image carrier.

The features and advantages of the static eliminators described above may be combined as appropriate as long as there is no problem.
In any of the first to sixth static elimination devices described above, the static elimination voltage applied to the static elimination member may be changeable according to the environment (temperature and / or humidity around the static elimination device). Further, the static elimination voltage applied to the static elimination member may be changeable according to the type of recording medium (plain paper, thin paper, special paper, etc.).

  In any case, as a representative example of the arrangement position of the static eliminator, a position on the downstream side of the transfer device in the conveyance direction of the recording medium can be given.

In any case, the static eliminator discharges the toner image formed on the image carrier from the recording medium in order to separate the recording medium transferred by the transfer device from the image carrier. Can be illustrated.
In this case, the “image carrier” is an image forming apparatus (typically a monochrome image forming apparatus) in which a toner image formed on an electrostatic latent image carrier such as a photoreceptor is directly transferred to a recording medium. An electrostatic latent image carrier can be exemplified.
Also, an image forming apparatus (primary transfer of a toner image formed on an electrostatic latent image carrier such as a photosensitive member to an intermediate transfer member such as an intermediate transfer belt, and secondary transfer from the intermediate transfer member to a recording medium ( As a representative example, in the case of a tandem type, four-cycle type color image forming apparatus), the intermediate transfer member which can be said to be one kind of image carrier can be exemplified.

The static eliminator also removes the recording medium on which the toner image formed on the image carrier is transferred by the transfer apparatus from the recording medium in order to separate the recording medium from the recording medium support on which the recording medium is electrostatically attracted. You may neutralize.
As an image forming apparatus in this case, a toner image formed on an electrostatic latent image carrier such as a photoreceptor is electrostatically supported by a recording medium support charged by, for example, a recording medium electrostatic adsorption charger. An image forming apparatus (typically a color image forming apparatus) transferred to a recording medium can be exemplified.

  As described above, according to the present invention, an image forming apparatus that transfers a toner image formed on an image carrier onto a recording medium by a transfer device, and discharges the toner image from the recording medium onto which the toner image has been transferred. When discharging the toner image from the recording medium to which the toner image is transferred, the toner image transferred to the recording medium is disturbed, the toner is scattered from the toner image, and image noise is generated due to the disturbance. It is possible to provide an image forming apparatus capable of performing static elimination that enables stable separation of the recording medium from the image carrier while suppressing excessive static elimination, and forming an image in which image noise is suppressed accordingly.

Embodiments of the present invention will be described below with reference to the drawings.
(Refer to First Embodiment FIG. 1, FIG. 2, FIG. 3)
FIG. 1 shows an example of an image forming apparatus according to the present invention.
The image forming apparatus shown in FIG. 1 is a tandem type full color printer. The printer PR1 has an endless intermediate transfer belt 4 wound around a driving roller 31 and a roller 32 facing the driving roller 31. The transfer belt 4 can be rotated counterclockwise in the figure (arrow direction in the figure) by a driving roller 31 driven by a belt drive unit (not shown).

  A cleaner 9 for cleaning secondary transfer residual toner and the like on the transfer belt 4 faces the transfer belt portion on the facing roller 32. The transfer belt portion on the drive roller 31 faces the secondary transfer roller 5, the neutralization device 6 </ b> A faces immediately downstream of the secondary transfer roller 5, and the separation claw 60 faces immediately downstream thereof. It is out.

The surface layer portion of the secondary transfer roller 5 is formed of an elastic material, and is pressed against the intermediate transfer belt 4 by a pressing unit (not shown) to form a nip portion between the intermediate transfer belt 4 and the intermediate transfer belt 4. , Or following the movement of the recording medium S fed into the nip as will be described later. A secondary transfer bias can be applied to the secondary transfer roller 5 from a secondary transfer bias power supply device (not shown).
The static eliminator 6A will be described later.

  A fixing device 8 is disposed above the static eliminator 6 </ b> A and the separation claw 60. Below the secondary transfer roller 5, a timing roller pair 70 is arranged, and further below that, a recording medium containing cassette (not shown) containing a recording medium such as recording paper is arranged.

In this example, the fixing device 8 includes a fixing roller incorporating a heat source such as a halogen lamp heater (not shown) and a pressure roller pressed against the fixing roller.
The recording medium S stored in a recording medium storage cassette (not shown) can be pulled out one by one by a medium supply roller (not shown) and supplied to the timing roller pair 70.

  Between the rollers 31 and 32 around which the intermediate transfer belt 4 is wound, the yellow image forming unit Y, the magenta image forming unit M, the cyan image forming unit C, and the rollers 32 to 31 are arranged along the transfer belt 4. Black image forming portions K are arranged in this order.

  Each of the image forming units Y, M, C, and K includes a drum-type photoconductor 11 as an electrostatic latent image carrier, and a charging device 12, an image exposure device 13, and a developing device 14 are provided around the photoconductor. The primary transfer roller 2, the cleaner 15 for removing and cleaning the primary transfer residual toner on the photosensitive member, and the optical eraser 16 for removing the residual charge on the photosensitive member in this order are arranged in this order.

The primary transfer roller 2 is opposed to the photoconductor 11 with the transfer belt 4 in between, and rotates as the belt travels. A primary transfer bias for primary transfer of the toner image formed on the photoreceptor 11 to the belt 4 can be applied to the primary transfer roller 2 from a primary transfer bias power supply device (not shown).
The exposure device 13 can perform image exposure on the photoconductor 11 using a laser beam in accordance with image information provided from a personal computer (not shown) or the like.

The photoconductor 11 in each image forming unit is a negatively chargeable photoconductor here, and can be driven to rotate clockwise in the drawing by a photoconductor drive motor (not shown).
A charging voltage can be applied to the charging device 12 in each image forming unit at a predetermined timing from a charging power supply device (not shown).

  The developing device 14 in each image forming unit is not limited thereto, but in this example, a negatively chargeable toner is used, and an electrostatic latent image formed on the photoconductor 11 is applied with a developing bias (not shown). Reversal development can be performed by a developing roller 141 to which a developing bias voltage is applied from a power supply device.

According to the printer PR1, an image can be formed using one or more of the Y, M, C, and K image forming units.
Taking a case where a full color image is formed using all of the image forming portions Y, M, C, and K as an example, first, a yellow toner image is formed in the yellow image forming portion Y, and this is formed on the transfer belt 4 as a primary. Transcript.

  That is, in the yellow image forming portion Y, the photosensitive member 11 is rotated in the clockwise direction in the drawing, and the image exposure device is applied to the charged area of the photosensitive member 11 whose surface is uniformly charged to a predetermined potential by the charging device 12. 13, yellow image exposure is performed, and a yellow electrostatic latent image is formed on the photoreceptor 11. This electrostatic latent image is developed by a developing roller 141 to which a developing bias of a developing device 14 having yellow toner is applied to become a visible yellow toner image, and the toner image is transferred onto the transfer belt 4 by the primary transfer roller 2. Primary transfer is performed. At this time, a primary transfer bias voltage is applied to the primary transfer roller 15 from a power supply device (not shown).

  Similarly, a magenta toner image is formed in the magenta image forming unit M and transferred to the transfer belt 4, a cyan toner image is formed in the cyan image forming unit C and transferred to the transfer belt 4, and in the black image forming unit K. A black toner image is formed and transferred to the transfer belt 4.

Yellow, magenta, cyan, and black toner images are formed at the timing when these toner images are transferred onto the intermediate transfer belt 4 in an overlapping manner.
Thus, the multiple toner image formed on the transfer belt 4 moves toward the secondary transfer roller 5 by the rotation of the transfer belt 4.

  On the other hand, the recording medium S is pulled out from a recording medium storage cassette (not shown) by the medium supply roller, supplied to the timing roller pair 70, and is on standby.

  In this way, the recording medium S waiting at the timing roller pair 70 is supplied to the nip portion between the transfer belt 4 and the secondary transfer roller 5 in accordance with the multiple toner image sent by the intermediate transfer belt 4. The multiple toner image is transferred onto the recording medium S by a secondary transfer roller 5 to which a secondary transfer bias voltage having a polarity (positive polarity) opposite to the normal charging polarity (negative polarity) of toner is applied from a power supply device (not shown). Secondary transfer is performed.

  The recording medium S onto which the toner image has been transferred in this manner can be smoothly separated from the intermediate transfer belt 4 which is an image carrier by being neutralized by the neutralization device 6A, and is guided to the separation claw 60 and guided to the belt. Leave 4 The separation claw 60 is not necessarily required.

  Thereafter, the recording medium S is passed through the fixing device 8 where the multiple toner images are fixed on the recording medium S under heat and pressure. The recording medium S is continuously discharged to a discharge tray by a pair of discharge rollers (not shown).

As described above, an image is formed. The neutralizing device 6A in the printer PR1 has the following characteristics.
First, the operation principle will be described. As shown in FIG. 2, the static eliminator 6A includes a static eliminator for neutralizing the recording medium. By applying a static eliminator voltage to the static eliminator, the recording medium A charge is removed on the back surface of S opposite to the surface on which the toner image is secondarily transferred.

  At that time, the image forming area of the recording medium S is weakly discharged with a low charge removal capability, and the outer ears of the image formation area are strongly discharged with a charge removal capability higher than the low charge removal capability. Accordingly, the toner image transferred to the recording medium S is disturbed, the toner is scattered from the toner image, and the generation of image noise due to them is suppressed, while the outer ear portion of the image forming area portion of the recording medium S is suppressed. By performing the static elimination with a high static elimination capability, the recording medium S can be stably separated from the image carrier (intermediate transfer belt 4).

  Specifically, as shown in FIG. 3, the static eliminator 6 </ b> A includes one static elimination member 61 a that faces the recording medium S, and the static elimination member 61 a that faces the outer ear portion of the image forming area portion of the recording medium S. The neutralization member 61a is set so that the gap g1 between the portion 611a and the recording medium is smaller than the gap g2 between the central portion 611b of the static elimination member facing the image forming area of the recording medium S and the recording medium. Yes. The neutralizing member 61a is formed by arranging a large number of sawtooth-shaped neutralizing needles in the longitudinal direction of the neutralizing member (corresponding to the width direction crossing the conveyance direction of the recording medium S). A static elimination voltage is applied to the static elimination member 61a at the timing of static elimination from one power supply device PW for applying the static elimination voltage. The static elimination voltage applied from the power supply device PW removes the charge from the recording medium S without excessively neutralizing the image forming area portion, and the recording medium S is intermediate-transferred to the outer portion of the image forming area portion. As long as static elimination that can be smoothly separated from the belt 4 can be performed, a static elimination voltage of 0 [V] or ground potential may be applied, or other static elimination voltage may be applied. This also applies to a power supply device for applying a static elimination voltage described later.

  In this static eliminator 6A, the gap g1 between the static elimination member portion 611a facing the outer ear of the image forming area portion of the recording medium S and the recording medium S is equal to the static elimination member portion 611b facing the image forming area portion of the recording medium S. Since it is set to be smaller than the gap g2 with respect to the recording medium S, excessive charge removal is performed on the image forming area by adjusting the charge removal voltage applied from the power supply device PW and / or adjusting the gaps g1 and g2. While neutralization can be performed with a low neutralization capability that does not occur, the outer ear is neutralized with a higher neutralization capability than the low neutralization capability, and the recording medium S is transferred to the image carrier (here, the intermediate transfer belt 4). ) Stably.

(Refer to FIG. 4 in the second embodiment)
The image forming apparatus according to the second embodiment is obtained by replacing the static eliminator 6A with the static eliminator 6B shown in FIG. 4 in the image forming apparatus shown in FIG. The other points are the same as those of the image forming apparatus of FIG.

  The static eliminator 6B includes a static elimination member 61b that faces the image forming area of the recording medium S and a static elimination member 61b 'that faces the outer ear of the image forming area of the recording medium. The neutralizing member 61b in the center is formed by arranging a number of sawtooth-shaped neutralizing needles in the longitudinal direction of the neutralizing member. The neutralization member 61b 'is made of a neutralization cloth, and has a higher neutralization capability per unit length in the recording medium width direction than the neutralization member 61b. Here, the neutralization cloth is a non-woven fabric containing conductive fibers, and has a neutralization needle density that is, for example, about several tens to 100 times that of the neutralization member having a serrated static elimination needle, and has excellent neutralization capability. It is.

  The distance between the charge eliminating member 61b and the recording medium S and the distance between the charge eliminating member 61b 'and the recording medium S are equal. The same static elimination voltage is applied to each static elimination member at the timing of static elimination from one power supply device PW.

  According to the static eliminator 6B, the static eliminator 61b ′ that faces the outer ear portion of the recording medium S has a higher static eliminator than the static eliminator 61b that faces the image forming area of the recording medium S. By adjusting the neutralization voltage, etc., the image forming area can be neutralized with a low neutralization capability that does not cause excessive neutralization, while the outer ear is neutralized with a higher neutralization capability than the low neutralization capability. Thus, the recording medium S can be stably separated from the intermediate transfer belt 4.

(Refer to FIG. 5 in the third embodiment)
The image forming apparatus according to the third embodiment is obtained by replacing the static eliminator 6A with the static eliminator 6C shown in FIG. 5 in the image forming apparatus shown in FIG. The other points are the same as those of the image forming apparatus of FIG.

  The static eliminator 6C includes a static elimination member 61c that faces the image forming area portion of the recording medium S and a static elimination member 61c 'that faces the outer ear portion of the image forming area portion of the recording medium S. Each of the static elimination members 61c and 61c 'is formed by arranging a number of serrated static elimination needles in the longitudinal direction of the static elimination member. However, the number of static elimination needles per unit length of the static elimination member (density of static elimination needles) is larger in the static elimination member 61c ′ than the static elimination member 61c (higher density of static elimination needles), and therefore the static elimination member 61c ′ is more in the direction. The static elimination capability per unit length is higher than that of the static elimination member 61c.

  The distance between the charge eliminating member 61c and the recording medium S and the distance between the charge eliminating member 61c 'and the recording medium S are equal. The same static elimination voltage is applied to each static elimination member at the timing of static elimination from one power supply device PW.

  According to the static eliminator 6C, the static eliminator 61c ′ that faces the outer ear portion of the recording medium S has a higher static eliminator than the static eliminator 61c that faces the image forming area of the recording medium S. By adjusting the neutralization voltage, etc., the image forming area can be neutralized with a low neutralization capability that does not cause excessive neutralization, while the outer ear is neutralized with a higher neutralization capability than the low neutralization capability. Thus, the recording medium S can be stably separated from the intermediate transfer belt 4.

(Refer to FIG. 6 in the fourth embodiment)
An image forming apparatus according to the fourth embodiment is obtained by replacing the static eliminator 6A with a static eliminator 6D shown in FIG. 6A in the image forming apparatus shown in FIG. The other points are the same as those of the image forming apparatus of FIG.

The neutralization device 6D includes a neutralization member 61d that faces the image forming area portion of the recording medium S and a neutralization member 61d ′ that faces the outer ear of the image formation area portion of the recording medium. Each of the static elimination members 61d and 61d ′ is formed by arranging a number of serrated static elimination needles in the longitudinal direction of the static elimination member. Both static elimination members have the same density of static elimination needles and the same distance from the recording medium.
A neutralization voltage is applied to the neutralization member 61d at the timing of neutralization from the power supply device PW1, and a neutralization voltage is applied to the neutralization member 61d ′ from the power supply device PW2 that applies a higher neutralization voltage than the power supply device PW1 (large in absolute value). The higher static elimination voltage is applied to the static elimination member 61d.

  According to the static eliminator 6D, the static eliminator 61d 'facing the outer ear is configured to be applied with a higher static eliminator voltage than the static eliminator 61d facing the image forming area. The image forming area of the medium S is neutralized with a low neutralization capability that does not cause excessive neutralization, while the outer ear portion of the recording medium S is neutralized with a higher neutralization capability than the low neutralization capability. Thus, the recording medium S can be stably separated from the intermediate transfer belt 4. For example, a case where -200 [V] is applied to the charge removal member 61d and -800 [V] is applied to the charge removal member 61d 'can be mentioned.

In the static eliminator 6D shown in FIG. 6 (A), the static eliminators 61d and 61d ′ are arranged slightly apart on the same plane, but as shown in FIG. 6 (B), the static eliminators 61d and 61d. 'May be placed on each of two parallel planes slightly separated.
Further, the charge removal member 61d ′ may be replaced with a charge removal cloth having a high charge removal capability.

(Refer to FIG. 7 and FIG. 8 in the fifth embodiment)
The image forming apparatus according to the fifth embodiment is obtained by replacing the static eliminator 6A with the static eliminator 6E shown in FIG. 7 in the image forming apparatus shown in FIG. The other points are the same as those of the image forming apparatus of FIG.

  The operating principle of the static eliminator 6E is shown in FIG. As shown in FIG. 8, the static eliminator 6 </ b> E is used as a recording medium, for example, an A4 size recording paper or an A5 size recording paper may be used. When the width of the image forming area of the recording medium is different, the static electricity is removed from the image forming area portion of the recording medium according to the width of the image forming area of the recording medium. Weak neutralization with a low static elimination capability that does not cause the occurrence of noise, while the outer ear portion of the image forming area portion of the recording medium is subjected to strong static elimination with a higher static elimination capability than the low static elimination capability. The image carrier is stably separated from the image carrier.

  Specifically, as shown in FIG. 7, the static eliminator 6E includes two types of static eliminators 6e and 6e ′ that are arranged in a direction crossing the conveyance direction of the recording medium S and face the recording medium, and have different static eliminating capabilities. ing. The charge removal member 6e is a charge removal member with a charge removal needle connected, and the charge removal member 6e 'is made of a charge removal cloth. If the same static elimination voltage is applied, the static elimination member 6e 'has a higher static elimination capability per unit length than the static elimination member 6e. In this example, although not shown, substantially the same static elimination voltage is applied to the static elimination members 6e and 6e 'from the same power supply device.

  The neutralizing member 6e ′ is disposed so as to face both sides of the neutralizing member 6e disposed so as to face the image forming area of the recording medium S and partially overlap the neutralizing member 6e, and is supported by the support arm 601. Has been. The two support arms 601 each supporting the charge removal member 6e 'are guided by the guide member 602 and can move in the recording medium width direction.

  A screw rod 603 is provided in parallel with the guide member 602, and one support arm 601 is screwed into the right screw portion carved in the screw rod, and the other support arm 601 is screwed into the left screw portion. The screw rod 603 is rotated by a motor 604 capable of forward / reverse operation, so that the pair of support arms 601 can approach and separate from each other, and thereby the left and right static elimination members 6e ′ can be brought closer to and away from each other. . Accordingly, by adjusting the positions of the left and right static eliminating members 6e 'according to the width of the recording medium S, the static eliminating member 6e' having a high static eliminating capability can face the outer ear portion of the recording medium having the width. The static elimination member 6e 'may be moved manually.

  According to the static eliminator 6E, the size of the recording medium used may be different, for example, A4 size recording paper may be used as the recording medium, or A5 size recording paper may be used. For this reason, when the width of the image forming area of the recording medium is different, depending on the width of the image forming area of the recording medium S, the static eliminating member 6e ′ having a high static eliminating ability faces the outer ear of the image forming area. The image forming area portion of the recording medium S is removed while the image forming area portion of the recording medium is adjusted by the neutralizing member 6e having a low neutralizing ability that does not cause excessive discharging. The outer ear portion is neutralized with a high neutralization capability by the neutralization member 6e ′, whereby the recording medium S can be stably separated from the intermediate transfer member 4.

(See FIG. 9 in the sixth embodiment)
The image forming apparatus according to the sixth embodiment is obtained by replacing the static eliminator 6A with the static eliminator 6F shown in FIG. 9 in the image forming apparatus shown in FIG. The other points are the same as those of the image forming apparatus of FIG. The operation principle of the static eliminator 6F is the same as that of the static eliminator 6E (see FIG. 8).

  The neutralization device 6F includes five neutralization members that are arranged in a direction crossing the recording medium conveyance direction and face the recording medium in this example. That is, a short static elimination member 6f2 is arranged on both sides of a relatively long central neutralization member 6f1, and a short static elimination member 6f3 is further arranged on the outer side thereof. These static elimination members are all static elimination members in which static elimination needles are connected, and the static elimination capability per unit length is the same, and the distance from the recording medium is also the same.

  A neutralization voltage can be applied to the central neutralization member 6f1 at the timing of neutralization from the power supply device PW1. Further, it is possible to selectively apply a static elimination voltage higher (larger in absolute value) than the static elimination voltage applied from the power supply device PW1 to each static elimination member 6f2 or each static elimination member 6f3 by the switching operation of the switch SW from the power supply device PW2. It is.

  Accordingly, depending on the width of the recording medium S, a higher static elimination voltage than the central static elimination member 6f1 can be applied to the left and right static elimination members 6f2 or 6f3 facing the outer ears of the image forming area of the recording medium having the width. it can.

  According to the static eliminator 6F, the static neutralization voltage applied to each static eliminator is adjusted, so that over-static charge is applied to the image forming area portion of the recording medium S according to the width of the image forming area of the recording medium S. While neutralization is performed by the neutralization member 6f1 having a low neutralization capability that is not generated, the neutralization member 6f2 or 6f3 having a higher neutralization capability than the low neutralization capability is applied to the outer ear portion of the image forming area portion of the recording medium S. The recording medium S can be stably separated from the intermediate transfer member 4 by performing static elimination.

  Note that the static elimination member that faces each outer ear of the recording medium is only divided into two in this example, but it is more finely divided, for example, for each static elimination needle, depending on the width of the recording medium, A high static elimination voltage may be selectively applied to one or more of these static elimination members.

(Refer to FIG. 10 in the seventh embodiment)
The image forming apparatus according to the seventh embodiment is obtained by replacing the static eliminator 6A with the static eliminator 6G shown in FIG. 10 in the image forming apparatus shown in FIG. The other points are the same as those of the image forming apparatus of FIG. The operation principle of the static eliminator 6G is the same as that of the static eliminator 6E (see FIG. 8).

  This neutralization device 6G has two neutralization members 6g1 and 6g2 that can face the recording medium. One static elimination member 6g1 has a plurality of static elimination needles connected in a direction that crosses the conveyance direction of the recording medium and over a length that can reach the entire width of the maximum recording medium among the usable recording media. It is what has been. The other static elimination member 6g2 has a static elimination needle partially formed.

  These static elimination members 6g1 and 6g2 are arranged in parallel so as to be close to each other, and the static elimination member 6g2 is moved in parallel with the static elimination member 6g1 automatically or manually by a driving mechanism (not shown). Can do. By such movement, a pair of regions G1 having a high density of static elimination needles can be formed as shown in FIG. 10A, and a pair of high density of static elimination needles can be formed as shown in FIG. 10B. The region G2 can be formed at an interval narrower than the interval between the pair of regions G1.

  In this example, the static elimination needle pitch is the same in both the static elimination members 6g1 and 6g2, and the static elimination needle of the static elimination member 6g2 is shifted by 0.5 pitch with respect to the static elimination needle of the static elimination member 6g1. Among the static elimination needle groups g formed at intervals in the member 6g2, the pitches of the static elimination needle groups g adjacent to each other on the left side and the right side are shifted by 1.5 pitches from the static elimination needle pitch. Thus, it is possible to selectively obtain a pair of regions G1 or G2 having a high density of the static elimination needles (with a density of static elimination needles twice the density of static elimination needles in each static elimination member).

  That is, according to the width of the image forming area of the recording medium, the two static elimination members 6g1 and 6g2 are moved relative to each other in a direction crossing the conveyance direction of the recording medium. The density of the static elimination needle facing the outer ear portion of the image forming area of the recording medium can be set larger than the density of the static elimination needle facing the image forming area. In the region where the charge removal needle density is high, the charge removal capability is higher than in the region where the charge removal needle density is lower than that. In general, in the case of a static elimination member having a static elimination needle, the thickness of the static elimination member is about 0.3 mm, and in this example, the thickness of the static elimination members 6g1 and 6g2 is about that, In the region where the static elimination needles overlap in both the static elimination members, substantially only the static elimination capability of one static elimination member is shown.

What is necessary is just to apply the substantially same static elimination voltage to the static elimination members 6g1 and 6g2 at the timing of static elimination from the power supply device PW.
According to the static eliminator 6G, depending on the width of the image forming area of the recording medium, the density of the static eliminator that does not cause excessive static elimination due to both the static eliminating members 6g1 and 6g2 to the image forming area portion of the recording medium. Can be removed in a low static elimination capacity region G having a small density, while a high static elimination capability area (area G1 or G2 depending on the recording medium width) having a high static elimination needle density is provided on the outer ear portion of the image forming area portion of the recording medium. The recording medium can be stably separated from the image carrier by performing static elimination.
Since the static elimination device 6G can reduce the movable range of the static elimination member, it has an advantage that the drive mechanism of the static elimination member can be simplified as compared with the static elimination device 6E of FIG.

  Even when any of the static elimination devices described above is employed, the static elimination voltage applied to the static elimination member may be changeable according to the environment (temperature and / or humidity of the ambient atmosphere of the static elimination device). By changing the charge removal capability by changing the charge removal voltage applied to the charge removal member according to the environment, it is possible to more reliably achieve the separation of the recording medium from the image carrier.

  In a low-temperature and low-humidity environment (for example, 10 ° C. and 15% RH), since the electrical resistance of a recording medium that is recording paper is generally high, the recording medium is static with an image carrier such as a transfer belt or a photoreceptor. The electroadsorption force becomes strong and it becomes difficult to separate from the image carrier. On the other hand, since the toner charge amount increases, toner scattering due to excessive static charge hardly occurs. Therefore, in a low-temperature and low-humidity environment, it is possible to increase the static elimination capability by raising the static elimination voltage compared to the normal environment, and not only to the outer ear of the image formation area of the recording medium, but also to the image formation area portion. In contrast, it is possible to increase the static elimination capability. Thereby, the separability of the recording medium can be improved.

  In a high-temperature and high-humidity environment (for example, 30 ° C. and 85% RH), since the electrical resistance of the recording medium is low, the electrostatic attraction force between the recording medium and an image carrier such as a transfer belt or a photoreceptor is weakened. It becomes easy to separate from the carrier. However, since the toner charge amount is reduced, the toner image is disturbed due to excessive charge removal, the toner is scattered, and image noise is likely to occur. Therefore, in a high-temperature and high-humidity environment, the occurrence of image noise can be more reliably suppressed by setting the static elimination voltage for the outer ear portion of the recording medium lower than in the normal environment.

  For example, in the case of the static eliminator 6D (FIG. 6), in a normal environment, -200 [V] is used for the static eliminator 61d corresponding to the image forming area, and -800 [V is used for the static eliminator 61d 'corresponding to the outer ear. V] can be exemplified, but in a high-temperature and high-humidity environment, -200 [V] is applied to the static elimination member 61d, and -400 [V] is applied to the static elimination member 61d 'corresponding to the outer ear. Can be illustrated. The condition for changing the static elimination voltage may be changed as appropriate according to the static elimination apparatus.

  In addition, in the case where any of the above-described static eliminators is adopted, the static elimination voltage applied to the static elimination member may be changeable according to the type of recording medium (plain paper, thin paper, special paper, or the like).

  For example, when the recording medium is thin paper, it is weaker than plain paper, and therefore easily follows the surface curvature of an image carrier such as a transfer belt or a photoreceptor, and is difficult to separate. For these types of recording media, separation from the image carrier is more reliably achieved by raising the static elimination voltage not only to the outer ear of the image forming area but also to the image forming area. it can. In this case, the occurrence of image noise due to excessive charge removal is a concern, but compared to the conventional case where the charge removal voltage is raised for the entire recording medium, the occurrence of image noise is suppressed to a level that can be ignored in practice. Is possible.

  The tandem color image forming apparatus has been described above as an example. However, the present invention uses four developing devices of yellow, magenta, cyan, and black in sequence on an electrostatic latent image carrier made up of a single photosensitive member or the like. A four-cycle type in which each color toner image is sequentially formed, each color toner image is superimposed and transferred to an intermediate transfer member, the multiple toner image is transferred to a recording medium, and the recording medium is separated from the intermediate transfer member using a static eliminator. The present invention can be applied to a color image forming apparatus such as a color image forming apparatus and a monochrome image forming apparatus.

  The present invention relates to an image forming apparatus for transferring a toner image formed on an image carrier onto a recording medium by a transfer device, and discharging the toner image from the recording medium onto which the toner image has been transferred using a discharging device. When removing the charge from the recording medium to which the toner has been transferred, the toner image transferred to the recording medium is disturbed, the toner is scattered from the toner image, and excessive charge removal that causes image noise is suppressed. The present invention can be used to provide an image forming apparatus that can perform static elimination that enables stable separation of the recording medium from the image carrier and can form an image with reduced image noise.

1 is a diagram illustrating a schematic configuration of an example (tandem color printer) of an image forming apparatus according to the present invention. It is a figure which shows the principle of operation of the static elimination apparatus in the printer of FIG. FIG. 2 is a diagram illustrating a specific configuration of a static eliminator in the printer of FIG. 1. FIG. 3 is a diagram illustrating a configuration of a static eliminator having an operation principle of FIG. 2 that is employed in another example of an image forming apparatus according to the present invention. FIG. 5 is a diagram illustrating a configuration of a static eliminator having an operation principle of FIG. 2 that is employed in still another example of an image forming apparatus according to the present invention. FIG. 5 is a diagram illustrating a configuration of a static eliminator having an operation principle of FIG. 2 that is employed in still another example of an image forming apparatus according to the present invention. It is a figure which shows the structure of the static elimination apparatus employ | adopted by the further another example of the image forming apparatus which concerns on this invention. It is a figure which shows the principle of operation of the static elimination apparatus shown in FIG. It is a figure which shows the structure of the static elimination apparatus of the same operation principle as FIG. 8 employ | adopted by the further another example of the image forming apparatus which concerns on this invention. It is a figure which shows the structure of the static elimination apparatus of the same operation principle as FIG. 8 employ | adopted by the further another example of the image forming apparatus which concerns on this invention.

Explanation of symbols

PR1 Color printer Y Yellow image forming unit M Magenta image forming unit C Cyan image forming unit K Black image forming unit 11 Photoconductor 12 Charging device 13 Image exposing device 14 Developing device 141 Developing roller 15 Cleaner 16 Optical eraser 2 Primary transfer roller 31 Driving roller 32 Opposing roller 4 Intermediate transfer belt 5 Secondary transfer roller 6A Neutralizing device 61a Neutralizing member 611a Neutralizing member part 611b Neutralizing member part g1 Gap between neutralizing member part 611a and recording medium S g2 Neutralizing member part 611b and recording medium Distance with S PW Power supply device 6B Static elimination device 61b, 61b 'Static elimination member 6C Static elimination device 61c, 61c' Static elimination member 6D Static elimination device 61d, 61d 'Static elimination member PW1, PW2 Power source device 6E Static elimination device 6e, 6e' Static elimination member 601 Support Arm 602 Guide member 603 Screw rod 604 Over data 6F static eliminator 6f1,6f2,6f3 discharging member 6G static eliminator 6g1,6g2 discharging member G1, G2 dense region g charge eliminating needle group removing needle 60 separating claw 70 timing roller pair 8 a fixing device 9 cleaner S recording medium

Claims (13)

  An image forming apparatus that transfers a toner image formed on an image carrier onto a recording medium by a transfer device, and discharges the toner image from the recording medium on which the toner image has been transferred using a discharging device. The image forming area portion of the medium is neutralized with a low static eliminating capability that does not cause excessive static elimination, while the outer ear portion of the image forming area portion of the recording medium is higher than the low static eliminating capability. An image forming apparatus, which is a static eliminator that performs static eliminating with a static eliminating capability.   The static eliminator includes a static eliminator facing the recording medium, and an interval between the portion of the static eliminator facing the outer ear of the image forming area portion of the recording medium and the recording medium is an image of the recording medium. The image forming apparatus according to claim 1, wherein the charge eliminating member is set to be smaller than a distance between the portion of the charge eliminating member facing the formation area and the recording medium.   The static eliminator includes a static eliminating member that faces an image forming area portion of the recording medium and a static eliminating member that faces an outer ear portion of the image forming area portion of the recording medium, and the static eliminating member that faces the outer ear portion is the image. The image forming apparatus according to claim 1, wherein the static eliminating member has a higher static elimination capability than the static elimination member facing the forming area.   The static eliminator includes a static elimination member that faces an image forming area portion of the recording medium and a static elimination member that faces an outer ear portion of the image forming area portion of the recording medium. The image forming apparatus according to claim 1, wherein a higher static elimination voltage is applied than a static elimination member facing the image forming area.   The static eliminator includes a plurality of types of static eliminators having different static eliminating capabilities, which are arranged in a direction crossing the conveyance direction of the recording medium and face the recording medium, and at least one of the plurality of types of static eliminators is The static eliminator has a higher static eliminator capacity than the static eliminator disposed on the image forming area portion of the recording medium. The image forming apparatus according to claim 1, wherein the position can be adjusted according to the width of the image forming area of the recording medium.   The plurality of types of static elimination members having different static elimination capabilities are arranged such that a static elimination member having a higher static elimination capability than the static elimination member is located on both sides of the static elimination member having the lowest static elimination capability in a direction crossing the conveyance direction of the recording medium. The static eliminator having a high static eliminating capability arranged in the position is adjustable so as to face the outer ear of the image forming area of the recording medium according to the width of the image forming area of the recording medium. 5. The image forming apparatus according to 5.   The static eliminator includes a plurality of static eliminators arranged in a direction crossing a conveyance direction of the recording medium and facing the recording medium, and the recording medium has a plurality of static elimination members according to the width of the image forming area of the recording medium. The image forming apparatus according to claim 1, wherein a static elimination voltage higher than that of the static elimination member facing the image forming area is applied to the static elimination member facing the outer ear portion of the image forming area.   The static eliminator has two static eliminating members that face a recording medium in which a plurality of static elimination needles are connected in a direction crossing the conveyance direction of the recording medium, and according to the width of the image forming area of the recording medium. The two static elimination members are moved relative to each other in a direction crossing the conveyance direction of the recording medium, so that the two static elimination members jointly face the outer ear portion of the image forming area of the recording medium. The image forming apparatus according to claim 1, wherein the density of the needle can be set larger than the density of the static elimination needle facing the image forming area.   The image forming apparatus according to claim 2, wherein the static eliminator is capable of changing a static elimination voltage applied to the static elimination member according to an environment.   The image forming apparatus according to claim 2, wherein the neutralizing device can change a neutralizing voltage applied to the neutralizing member according to a type of a recording medium.   The image forming apparatus according to claim 1, wherein the static eliminator is provided on the downstream side of the transfer device in the conveyance direction of the recording medium.   12. The charge removing device discharges electricity from the recording medium in order to separate the recording medium onto which the toner image formed on the image bearing member has been transferred by the transfer device from the image bearing member. The image forming apparatus according to any one of the above. The static eliminator is configured to separate the recording medium on which the toner image formed on the image carrier is transferred by the transfer apparatus from the recording medium support that electrostatically attracts the recording medium. The image forming apparatus according to claim 1, wherein the image forming apparatus removes electricity from the image forming apparatus.