JP2004184822A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that uniformly and satisfactorily removes charges on recording paper after transfer without setting or adjusting complicated conditions and hinders scatter of toner even when the recording paper contacts the other members within a carrying passage before fixing. <P>SOLUTION: A self-dischargeable sheetlike flexible member 5 is disposed in a given position between a conveying guide member 4 and a transfer position Q opposite the transfer device 2 of an image carrier 1 which rotates while carring an unfixed toner image before transfer. The self-dischargeable sheetlike flexible member contacts the back of transferred recording paper P peeled from the image carrier 1, over the entire area in the direction of the width of the paper P intersecting the direction in which the paper P is conveyed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a printer, a copying machine, a facsimile, or a multifunction peripheral having both of these functions, which forms an image made of toner using an electrophotographic system or an electrostatic recording system. More particularly, the present invention relates to an image forming apparatus which is improved to prevent occurrence of image disorder after electrostatically transferring an unfixed toner image onto recording paper.
[0002]
[Prior art]
Image formation by this type of image forming apparatus is generally performed as follows. That is, an electrostatic latent image is formed on a rotating photoreceptor such as a drum by an electrophotographic process or the like, and a toner as a developer charged to a predetermined polarity is electrostatically attached to the electrostatic latent image to form a toner image. After image formation, the unfixed toner image is electrostatically transferred to a recording sheet directly from a photosensitive member or via an intermediate transfer member. Finally, the recording sheet after the transfer of the toner image is conveyed to a fixing device to fix the toner image on the recording sheet, thereby forming an image.
[0003]
Among these, for the electrostatic transfer, a transfer device including a corona charger, a fixing roll for applying a transfer voltage, and the like is used, and the transfer device transfers an image to a photoconductor, an intermediate transfer member, or another image carrier at the time of transfer. By applying a charge (or voltage) having a polarity opposite to the toner charging polarity to the back surface of the recording paper in contact with the recording paper, the charged toner (image) is electrostatically attached to the recording paper.
[0004]
By the way, in an image forming apparatus that performs such electrostatic transfer, (the back surface of) the recording sheet after the transfer and before the fixing comes into contact with a part such as a sheet guide in the conveyance process, and the recording sheet is transferred. The charge is discharged, the balance of the charge distribution is disrupted, and toner scattering occurs, which may disturb the toner image and lower the image quality.
[0005]
For this reason, an image forming apparatus that has taken the following countermeasures has conventionally been proposed.
[0006]
For example, a charge elimination brush is fixed to a high-resistance transfer paper guide plate provided on a downstream side wall of a shield case of a transfer charger, and the tip of the charge elimination brush is brought into contact with the recording paper after the transfer to thereby charge the recording paper. There has been proposed an image forming apparatus configured to remove electricity from the image forming apparatus (Patent Document 1). Further, a discharging member for applying a discharging voltage is installed at an adjacent position on the downstream side of the transfer device in the sheet conveying direction so as to be in a non-contact state with respect to the recording sheet after the transfer, and a power supply path of the discharging member is provided. There has been proposed an image forming apparatus in which a predetermined resistor is inserted into the image forming apparatus and adjusted so that the charge on the recording sheet is appropriately removed by the charge removing member (Patent Document 2).
[0007]
[Patent Document 1] JP-A-7-230221 [Patent Document 2] JP-A-2001-228718
[Problems to be solved by the invention]
However, in any of the image forming apparatuses as proposed above, there is a case where the deterioration of the image quality due to the scattering of the toner cannot be sufficiently solved.
[0009]
In particular, in the former case, the static elimination brush does not make uniform contact with the recording paper in a continuous state (for example, there is a case where the brush bristles fall in a deviated direction and a non-existent portion occurs and does not contact the paper). Therefore, a portion causing uneven charge removal may occur, and the presence of such a portion may cause toner scattering. On the other hand, in the latter case, the optimal conditions of the static elimination voltage applied to the static elimination member and the resistor placed in the power supply path are determined by the charging characteristics of the toner, the environmental conditions such as humidity, and the state of separation of the paper from the image carrier. Since it fluctuates according to the same factors, it is difficult to find the optimum condition, and depending on the condition, good static elimination may not be performed in some cases.
[0010]
As a measure to prevent the occurrence of the problem due to the scattering of the toner, it is conceivable to adopt a configuration in which the recording paper after transfer is prevented from coming into contact with components in a transport path as far as possible until the recording paper is introduced into the fixing device. However, in practice, it is difficult to realize such a sheet transport path structure, and it is not possible to completely avoid contact with components of various types of recording paper.
[0011]
The present invention has been made in order to solve such a problem, and its main object is to uniformly charge the recording paper after transfer without complicated condition setting and adjustment. Another object of the present invention is to provide an image forming apparatus in which even if the recording sheet comes into contact with other components in a conveyance path before fixing, toner scattering is less likely to occur.
[0012]
[Means for Solving the Problems]
As shown in FIG. 1, an image forming apparatus according to the present invention includes an image carrier 1 that rotates while supporting an unfixed toner image formed in accordance with image information, and an image carrier 1 facing the image carrier 1. A transfer device 2 that is disposed and that electrostatically transfers the unfixed toner image to a recording sheet P conveyed so as to be in contact with the toner image bearing surface of the carrier 1; And a conveyance guide which is disposed between the fixing device 3 and the transfer device 2 and conveys the transferred recording paper P separated from the image carrier 1 to the fixing device 3. In the image forming apparatus provided with the member 4, the image carrier 1 is separated from the carrier 1 at a predetermined position between a transfer position Q facing the transfer device 2 and the transfer guide member 4. Of the recording paper P in the transport direction (the dashed line in the figure) In which characterized in that a sheet-like soft member 5 of the self-discharge of contact over the entire width intersecting the arrow direction) indicated.
[0013]
According to such an image forming apparatus, the self-discharge sheet-like soft member comes into continuous and uniform contact over the entire width direction of the back surface of the recording paper after the transfer, and further, the self-discharge property Thereby, the charge on the back surface of the recording paper can be evenly removed. Accordingly, even if the recording paper that has passed through the sheet-like soft member comes into contact with the conveyance guide member 4 that is present after that, scattering of toner or the like is less likely to occur.
[0014]
Here, the image carrier 1 carries an unfixed toner image immediately before transfer, and specifically, records an image carrier such as a photoconductor on which a toner image is formed, and records the toner image. An image carrier such as an intermediate transfer body that relays and conveys to a transfer position to a sheet. The form of the image carrier is, for example, a drum (roll) form, a belt form, or the like. The toner image is formed based on image information input from a document reading device, an externally connected device, an external storage medium, or the like, using a method such as an electrophotographic method or an electrostatic recording method.
[0015]
The transfer device 2 may be any device that performs electrostatic transfer, and mainly includes a device in which a transfer roller to which a transfer voltage is applied is brought into contact with the image carrier 1 and a device including a corona discharger (for example, corotron). is there. Reference numeral 7 in the drawing denotes a power supply device for applying a transfer voltage. The fixing device 3 is not particularly limited as long as it can fix an unfixed toner image on the recording paper P. The transport guide member 4 is a member that functions when transporting the recording paper after the transfer to the fixing device 3, and is specifically a paper transport guide, a paper transport belt device, or the like. The recording paper P may be any paper as long as it can be transported in the apparatus and can transfer and fix a toner image, and examples thereof include plain paper, coated paper, cardboard, OHP sheets, postcards, envelopes, and the like. The back surface of the recording paper is a surface opposite to the surface on which the transfer of the toner image is performed.
[0016]
The sheet-like soft member has a continuous form like a sheet and has soft physical properties. The softness is such a flexibility that the recording paper itself can be uniformly deformed so as not to hinder the conveyance state of the paper when the recording paper comes into contact with the paper. In addition, the self-discharge property is a property that causes a self-discharge. As a result, the sheet-like soft member performs charge elimination of the charge of the recording paper by its self-discharge, and does not perform charge elimination by applying a charge elimination voltage or charge elimination by grounding. Examples of the sheet-like soft member having such a self-discharge property include a synthetic fiber such as rayon, a cloth material made like a nonwoven fabric using a fiber material obtained by weaving a conductive member, and a conductive material. It is a plastic film (for example, a vinyl film) provided with conductivity by mixing. This sheet-like soft member is installed so as to be electrically floating without being grounded.
[0017]
In the image forming apparatus of the present invention, an electrically insulating partition may be interposed between the sheet-like soft member 5 and the transfer device 2. As a result, even between the sheet-like soft member and the transfer device in close proximity to each other, unnecessary discharge is unlikely to occur, and interference that impairs the functions of both members does not occur.
[0018]
The electrically insulating partition is made of plastic or the like as a partition plate, a structure also serving as a paper intrusion prevention guide, or the like. The arrangement is performed in a state where the above-described discharge preventing effect is obtained and the sheet is not obstructed in sheet conveyance. Further, it is preferable that a portion of the partition wall on the side of the sheet transport path is formed in a shape such that the recording sheet after the transfer is prevented from sneaking between the transfer device and the soft sheet member.
[0019]
In addition, between the sheet-like soft member 5 and the transfer device 2, it is preferable to provide a peeling neutralizing member 6 for applying a neutralizing voltage. Thereby, first, the charge existing on the back surface of the recording sheet when the recording sheet is peeled off from the image carrier 1 at the time of transfer is first removed by the peeling electricity removing member 6, thereby realizing stable peeling of the paper from the image carrier. Become so. Accordingly, it is ensured that the peeled recording sheet is stably contacted by the sheet-like soft member 5 located on the downstream side of the neutralizing member 6 in the sheet conveying direction, and the sheet by the soft member 5 The burden of charge removal on the back surface is reduced, and more appropriate charge removal is performed. Reference numeral 8 in FIG. 1 indicates a power supply device that applies a neutralization voltage to the neutralization member 6.
[0020]
In the case where the stripping neutralizing member 6 is provided, an electrically insulating partition wall may be interposed between the sheet-shaped soft member 5 and the stripping neutralizing member 6 and between the neutralizing member 6 and the transfer device 2. . Thus, even between the sheet-like soft member, the static elimination member, and the transfer device, which are closer to each other, unnecessary discharge hardly occurs, and interference that impairs the functions of the three members occurs. Disappears. About this partition, the same structure as the case of the above-mentioned partition can be adopted.
[0021]
Further, when a transfer roll to which a transfer voltage is applied is brought into contact with the image carrier 1 as a transfer roll, a transfer roll having a diameter of D (mm), When the separation distance from the transfer position where the carrier contacts and the sheet-like soft member is E (mm), and the separation distance from the transfer position to the separation neutralizing member is J (mm), the sheet-like soft member is It is preferable to set a positional relationship that satisfies the condition of D>J> E.
[0022]
As a result, the sheet-like soft member including the static elimination member is particularly arranged at a position closer to the transfer position. As a result, the charge elimination by the charge eliminating member and the sheet-like soft member on the back surface of the recording sheet after the transfer is performed immediately after the transfer, and the above-described peeling of the recording sheet from the image carrier and the subsequent charge elimination of the sheet back surface are performed. It will be done more effectively.
[0023]
It is preferable that the transfer device 2 and the soft sheet member 5 or the transfer device 2, the soft sheet member 5 and the charge removing member 6 be integrated as one unit. Also, in this case, the sheet-like soft member 5 may be attached and installed on a portion of the support member (frame) of the unit on the downstream side in the sheet transport direction.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a configuration diagram showing a main part of a printer to which the present invention is applied. Solid arrows in the figure indicate the rotation direction of each component.
[0025]
This printer mainly includes an image carrying roll 10, a transfer unit 20 including a transfer roll 21, a fixing device 30, and a paper transport guide 40. Reference numeral P in the figure denotes recording paper, and reference numeral 15 denotes a recording paper P supplied from a paper feeding device (not shown) to a transfer position between the image carrying roll 10 and the transfer roll 21 of the transfer unit 20 at a predetermined timing. It is a registration roll, and an alternate long and short dash line arrow indicates a transport path and a transport direction of the recording paper P.
[0026]
The image carrying roll 10 is a photosensitive drum or an intermediate transfer roll that rotates in the direction of the arrow and carries an unfixed toner image before transfer. In the case of a photosensitive drum, a toner made of charged toner corresponding to image information is formed on the surface of the photosensitive drum by an image forming device (charging device, image exposure device, developing device, etc.) using an electrophotographic method (not shown). An image is formed and is conveyed to the transfer position as it is. In the case of the intermediate transfer drum, the unfixed toner image formed as described above is carried on the photosensitive drum or the like by transfer, and then conveyed to the transfer position by rotation of the intermediate transfer drum. The intermediate transfer drum may be a single drum or a combination of a plurality of drums.
[0027]
The fixing device 30 fixes the toner image transferred from the image bearing roll 10 by the transfer unit 20 onto the recording paper P, and includes a heating roll 31 that rotates while being heated and held at a fixing temperature by a heating source. The pressure roller 31 mainly rotates by pressing. In the fixing device 30, the transferred recording paper P is introduced into and passed through a fixing nip portion between the heating roll 31 and the pressure roll 32, so that the toner image is heated and pressed to be fixed on the recording paper P. It has become. The fixing device 30 is not limited to the roll nip type, but may be another type.
[0028]
The paper transport guide 40 is for transporting and guiding the recording paper P to which the toner image has been transferred toward the fixing device 30, and includes a first transport guide 41 disposed downstream of the transfer unit 20 and a first transport guide 41. A second conveyance guide 42 is provided between the conveyance guide 41 and the fixing device 30. Both the first transport guide 41 and the second transport guide 42 are made of plastic or the like, and are attached to a support frame or the like of the printer body. The recording paper P after the transfer is guided and transported in a direction of the fixing device 30 by the paper transport guide 40, and is finally introduced into a fixing nip portion of the fixing device 30.
[0029]
The transfer unit 20 for electrostatically transferring the unfixed toner image before transfer carried on the image carrying roll 10 onto the recording paper P as described above is pressed against the image carrying roll 10 as shown in FIGS. Transfer roller 21 that rotates by rotating the transfer roll 21, a transfer power supply device 25 that applies a transfer voltage to the transfer roll 21, a static elimination needle 60 installed at a position near the downstream side of the transfer roll 21 in the sheet conveyance direction, and a static elimination needle An electricity-insulating unit frame 25 mainly comprising a static elimination power supply device 65 for applying a static elimination voltage to 60 and a static elimination cloth 50, and made of a plastic molded product such as polypropylene having the property of being negatively charged. Are arranged as appropriate.
[0030]
The transfer roll 21 has a roll structure in which an elastic layer 23 made of epichlorohydrin rubber or the like is formed on a metal roll core 22, and a transfer gear 24 attached to one shaft of the roll core 22. It rotates by the transmitted driving force. Then, at the time of transfer, a transfer voltage having a polarity opposite to the charging polarity of the toner image is applied to the transfer core 21 from the transfer power supply device 25 under constant voltage control. As a result, the recording paper P introduced into the transfer position Q between the image carrying roll 10 and the transfer roll 21 is applied to the image carrying roll 10 by the transfer electric field formed between the image carrying roll 10 and the transfer roll 21. The upper toner image is electrostatically transferred.
[0031]
The static elimination needle 60 is made of stainless steel or the like, and has a front end (upper end) facing the paper transport path formed in an uneven shape like a saw tooth. Further, the static elimination needle 60 is placed inside the transfer unit frame 25 in a state parallel to the axial direction of the transfer roll 21 (the direction orthogonal to the paper transport direction) (FIG. 5), and the upper end portion 60a is located at the transfer position. It is mounted so as to be as close as possible to Q and not to enter the paper transport path (dotted line arrow) so as not to contact the paper. On the transfer roll 21 side of the static elimination needle 60, a partition plate 26 made of an electrically insulating plastic and having a paper intrusion prevention guide 26 a formed on the upper end side in a state of separating the static elimination needle 560 and the transfer roll 21. It is provided on the transfer unit frame 25.
[0032]
To the neutralization needle 60, a neutralization voltage having a polarity opposite to the charge applied to the back surface of the recording paper P by the transfer roll 21 is applied from a neutralization power supply device 65. As a result, the charge on the back surface of the recording sheet P after passing through the transfer position Q is removed so as to reduce the charge. As a result, the electrostatic attraction force between the sheet P and the image carrying roll 10 is reduced, so that the sheet P after transfer is easily separated from the image carrying roll 10.
[0033]
The static elimination cloth 50 is a soft cloth material (manufactured by Nippon Vileen Co., Ltd .: DENKITOL VLS6209F) formed in an elongated strip shape by a conductive non-woven cloth. Actually, the thickness is about 0.4 mm, the length is substantially the same as the length of the transfer roll 21 in the axial direction, and the width is about 310 mm.
[0034]
Then, as shown in FIGS. 3 to 5, the neutralization cloth 50 has its upper end 50 a in a state parallel to the axial direction of the transfer roll 21 and a state in which a predetermined amount exists in the paper transport path. The lower end portion 50b of the cloth is adhered to the outer wall portion 25a of the transfer unit frame 25 on the downstream side in the sheet transport direction with an adhesive or the like. As a result, the static elimination cloth 50 is disposed at a position closer to the transfer position than the first conveyance guide 41, and the upper end 50a of the cloth crosses the rear surface of the recording paper P after the transfer in the conveyance direction. The entire area in the width direction. The outer wall portion 25a of the unit frame is installed so as to stop at a position that does not enter the paper transport path, and functions as a partition wall 27 interposed between the static elimination cloth 50 and the static elimination needle 60. I have.
[0035]
In particular, the static elimination cloth 50 is separated from the transfer position Q by a portion M of the cloth upper end 50a that intersects (preferably perpendicularly intersects) with the sheet transport path so as to be arranged as close as possible to the transfer position. mm) is set to be smaller than the diameter D (mm) of the transfer roll 21 (FIG. 4). The distance E from the transfer position Q of the static elimination cloth 50 is determined by the distance J from the transfer position Q of the static elimination needle 60 because the static elimination cloth 50 is arranged at a position sandwiching the static elimination needle 60 from the transfer position. Is also a large value. In such a positional relationship, since a structure in which the static elimination cloth 50 and the static elimination needle 60 are integrated with the transfer roll 21 as the transfer unit 20 is employed, the accuracy is easily ensured.
[0036]
In addition, the neutralization cloth 50 has a plurality of wedge-shaped ribs 28 formed such that the upper end portion 50a is protruded toward the upper end portion of the outer wall surface portion 25a of the transfer unit frame. It is attached to be slightly warped. Thus, when the leading end portion of the recording paper P after the transfer comes into contact with the static elimination cloth 50, the upper end of the static elimination cloth 50 is deformed so as to be easily and surely bent, and does not become an obstacle to sheet conveyance.
[0037]
Further, as shown in FIGS. 3 and 4, between the upper portion of the unit frame outer wall surface portion 25a serving as the partition wall 27 and the upper portion of the partition wall 26, the two are wrapped therebetween in the sheet transport direction. The arch-shaped members 29 are formed in a state of being arranged in parallel at intervals in the axial direction of the transfer roll 21. The arch-shaped member 29 is formed of the same material as the unit frame, and is electrically insulating. As a result, it is possible to prevent the recording paper P after the transfer from slipping into the frame 27 of the transfer unit 20 and causing a paper jam.
[0038]
In the transfer unit 20 provided with such a static elimination cloth 50, the recording paper P after the transfer passes through the static elimination needle 60 and is located downstream of the static elimination needle 60 in the paper transport direction and in the transport path. It passes with the back surface thereof in contact with the static elimination cloth 50.
[0039]
As a result, as shown in FIG. 6, the charge (for example, positive charge) e present on the back surface of the recording paper P after the transfer is neutralized by the static elimination needle 60, and the static elimination by the static elimination needle 60 causes unevenness. However, after that, the static elimination cloth 50 is surely touched and the static elimination by the self-discharge by the static elimination cloth 50 will be surely eliminated. In addition, the charge elimination by the charge elimination cloth 50 at this time is such that the charge elimination cloth 50 is arranged continuously in the axial direction of the transfer roll 21 and is continuous on the back surface of the recording paper P over the entire width direction in the conveyance direction. Since it comes into contact in a state, there is no unevenness in static elimination.
[0040]
As a result, the recording paper P after the transfer is in a state in which the charge on the back surface is satisfactorily discharged, and after passing through the discharging cloth 50, comes into contact with the paper transport guide 40 such as the first paper guide 41 and is transported. Even if it occurs, no charge discharge occurs on the back surface of the paper due to the contact, and toner does not scatter. Therefore, in this printer, the toner image is fixed in a state where the toner image has been transferred without the toner scattering phenomenon on the recording paper P after the transfer, so that the deterioration of the image quality due to the toner scattering is prevented. . In addition, the static elimination cloth 50 may be deformed or deteriorated with time to reach its end of life. However, since the transfer unit 20 has an integrated structure, it is necessary to replace the transfer roll 21 and the like based on the end of life. It can be replaced at the same time according to the convenience.
[0041]
Then, an image forming test was performed under the following conditions using a printer having such a transfer unit 20.
[0042]
As a toner image, a test image (an image like a fine grid pattern) was formed with toner charged to a negative polarity. In this test, +2000 V was applied as a transfer voltage, and -1000 V was applied as a neutralization voltage. The diameter D of the transfer roll 21 was 16 mm, and the distance E from the transfer position of the charge eliminating cloth 50 was 13 mm. The distance between the upstream end of the first transport guide 41 in the paper transport direction and the neutralizing cloth 50 was 17 mm. The process speed was 104 mm / sec. As the image carrying roll 10, an intermediate transfer drum that relays and transports a test image formed on an image carrier such as a photosensitive drum to a transfer position on a recording sheet was used, and a voltage of 950 V was applied to the intermediate transfer drum.
[0043]
As a result, in the obtained test image, generation of an image defect due to toner scattering was not confirmed.
[0044]
For reference, instead of installing the static elimination cloth 50 in the transfer unit 20, the upper end of the static elimination cloth may be present in the paper transport path at the upstream end of the first transport guide 41 in the paper transport direction. When the same image forming test was carried out by attaching the recording paper P so as to be in the state, it was confirmed that the traveling state of the recording paper P after the transfer became unstable, and the traveling of the recording paper became poor.
[0045]
This running failure is caused by the fact that the static elimination cloth 50 is attached to the first conveyance guide 41 having a shape-preserving property made of a plastic molded product. It is presumed that the static elimination cloth has been generated as an obstacle on the path of the sheet because it is in a strong state that is less likely to be deformed. In addition, the farther the static elimination cloth is away from the transfer position Q, the more the posture of the paper after the transfer is generated, and the more easily the variance of the attaching position and posture of the static elimination cloth is generated. It is presumed that the contact state also fluctuates, and as a result, the paper running property becomes unstable.
[0046]
Further, in this printer, even if the static elimination needle 60 (including the static elimination power supply device 65) in the transfer unit 20 is removed, as long as the recording sheet P after the transfer is satisfactorily peeled off from the image carrying roll 10, The neutralization of the back surface of the recording paper P is performed by the neutralization cloth 50.
[0047]
【The invention's effect】
As described above, according to the image forming apparatus of the present invention, by arranging the self-discharge sheet-like soft member at a predetermined position, it is possible to uniformly and satisfactorily remove the charge of the recording sheet after the transfer. Accordingly, even if the recording sheet comes into contact with the conveyance guide member in the conveyance path before fixing, toner scattering is less likely to occur, and it is possible to prevent the deterioration in image quality due to the toner scattering. Moreover, since such an effect can be realized by installing the above-mentioned sheet-like soft member, it is possible to obtain it without complicated setting and adjustment of conditions.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a main part of an image forming apparatus of the present invention.
FIG. 2 is a schematic configuration diagram illustrating a main part of the printer according to the embodiment.
FIG. 3 is an essential part perspective view showing a part of a transfer unit.
FIG. 4 is a schematic diagram illustrating a configuration of a transfer unit.
FIG. 5 is an explanatory plan view showing a positional relationship between a static elimination cloth and a static elimination needle.
FIG. 6A is an explanatory diagram illustrating a state of retaining electric charge of a recording sheet immediately after passing through a static elimination needle, and FIG. 6B illustrates a state of retaining electric charge of the recording sheet immediately after passing through a static elimination cloth after passing through a static elimination needle; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Transfer device, 3 ... Fixing device, 4 ... Conveying guide member, 5 ... Soft sheet member, 6 ... Static removing member, 10 ... Image carrying roll, 20 ... Bias roll type transfer device, 21 ... Transfer roll, 30: Roll nip type fixing device, 40: Paper transport guide, 50: Static elimination cloth, 60: Static elimination needle, P: Recording paper, Q: Transfer position.

Claims (5)

An image carrier that carries an unfixed toner image formed in accordance with image information and rotates, and a recording medium that is disposed to face the image carrier and is conveyed so as to be in contact with the toner image carrying surface of the carrier. A transfer device that electrostatically transfers the unfixed toner image to paper, a fixing device that fixes the transferred unfixed toner image to recording paper, and the image transfer device that is disposed between the fixing device and the transfer device. A conveyance guide member for conveying and guiding the recording paper after transfer separated from the carrier to the fixing device;
A predetermined position between a transfer position facing the transfer device of the image carrier and the conveyance guide member, on the back surface of the transferred recording sheet separated from the carrier, over the entire width direction crossing the conveyance direction. An image forming apparatus comprising a self-discharge sheet-like soft member in contact with the image forming apparatus. The image forming apparatus according to claim 1, wherein an electrically insulating partition wall is interposed between the soft sheet member and the transfer device. 2. The image forming apparatus according to claim 1, further comprising an exfoliating charge removing member configured to apply a charge removing voltage between the soft sheet member and the transfer device. 3. The image forming apparatus according to claim 3, wherein electrically insulating partitions are interposed between the sheet-like soft member and the exfoliating member and between the exfoliating member and the transfer device. When using a bias roll type transfer device that makes a transfer roll to which a transfer voltage is applied contact the image carrier as the transfer device,
The diameter of the transfer roll is D (mm), the separation distance from the transfer position at which the transfer roll contacts the image carrier to the sheet-like soft member is E (mm), and the separation from the transfer position to the removing member for peeling. 5. The image forming apparatus according to claim 3, wherein when the distance is J (mm), the sheet-like soft member is set to have a positional relationship satisfying a condition of D>J> E.

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