JP2001199592A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of surely guiding any sheet such as a low stiffness and thin sheet or the like. SOLUTION: A guide member 30 for guiding a sheet S having a transferred image thereon, to a fixing part 20 is mounted between the fixing part 20 and a transferring part 5, and the charged sheet S is conveyed toward the fixing part 20 in a state that a surface opposite to a toner image transfer surface is upwardly placed while electrostatically attracting the charged sheet S in transferring the toner image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an arrangement for guiding a sheet on which a toner image has been transferred to a fixing unit.

[0002]

2. Description of the Related Art In a conventional image forming apparatus, a toner image formed by developing a latent image on an image carrier is transferred to a sheet by a transfer unit and then fixed to the sheet by a fixing unit. There is a multicolor image forming apparatus in which a plurality of photosensitive drums (image carriers) are arranged in a line as an example of such an image forming apparatus.

[0003] Such a multicolor image forming apparatus is roughly divided into a plurality of photosensitive drums 201 as shown in FIG.
FIG. 7 shows a horizontal in-line configuration in which
As shown in FIG. 2, there is a vertical in-line configuration in which a plurality of photosensitive drums 201 are arranged in a vertical direction.

Here, the horizontal in-line type shown in FIG. 6 is low in height, and after the image is transferred, the transfer material remains fixed on the transfer belt 204 while the fixing unit 202 is in place.
Therefore, there is an advantage that the transfer is stabilized because the transfer is substantially horizontal. On the other hand, the vertical type in-line configuration shown in FIG. 7 is high in height, but the installation area can be made small, which is advantageous for a desktop printer, for example. Just do
There is an advantage that the transfer material transport path R1 indicated by a thick solid line can be easily accessed.

[0005]

In such a conventional image forming apparatus, the transfer paper on which the toner image has been transferred is temporarily separated from the transfer belt 204 when the transfer paper is conveyed to the fixing unit 202. The sheet is conveyed to the fixing unit 202.

However, when the transfer material is conveyed to the fixing unit 202 while being separated from the transfer belt 204 as described above, if the transfer material is light, such as thin paper, and has a weak stiffness, the leading end of the paper will hang down. If the leading end hangs down in this way, the transfer of the transfer material becomes unstable, and the leading end of the paper may enter the lower portion of the fixing unit 202 without being pinched by the fixing nip, and a jam may occur.

[0007] For example, as shown in FIG.
The configuration in which the transfer material is transported above 3 or the like is advantageous in terms of cost and usability in an electrophotographic color printer or the like, since the transport path can be accessed simply by opening and closing the upper exterior. However, as described above, there is a problem in the transferability of the transfer paper, and it has not been practically used at present.

Accordingly, the present invention has been made in view of such circumstances, and it is an object of the present invention to provide an image forming apparatus which can surely guide a transfer sheet (sheet) such as a thin sheet of thin paper to a fixing unit. It is the purpose.

[0009]

According to the present invention, there is provided an image forming apparatus wherein a toner image formed by developing a latent image on an image carrier is transferred to a sheet and then fixed on the sheet. A transfer unit that transfers the toner image to the sheet, a fixing unit that is provided above the transfer unit and fixes the toner image transferred to the sheet to the sheet, and is provided between the fixing unit and the transfer unit. A guide member for guiding the sheet to the fixing unit, wherein the sheet charged during the transfer of the toner image is conveyed toward the fixing unit while being electrostatically attracted by the guide member. It is characterized by having done.

Further, according to the present invention, the guide member is formed of an insulator and a plurality of ribs on which the sheet slides, and is provided between the ribs and formed of a conductor, and the guide member is formed of an electrostatic material. And a transport guide plate that is grounded so as to be attracted.

Further, the present invention has a transport path for transporting the sheet to the fixing section with the surface opposite to the toner image transfer surface facing upward, and the guide member has a toner image transfer surface of the sheet. And is arranged above the transport path so as to adsorb the surface on the opposite side.

According to another aspect of the present invention, there is provided an image forming apparatus in which a toner image formed by developing a latent image on an image carrier is transferred to a sheet and then fixed on the sheet. A transfer unit for transferring, a fixing unit for fixing the toner image transferred to the sheet to the sheet, a guide member provided between the fixing unit and the transfer unit, and guiding the sheet to the fixing unit; The toner image is transferred toward the fixing unit with the toner image transfer surface facing downward while electrostatically attracting the sheet charged during the transfer of the toner image by the guide member. Things.

Further, according to the present invention, the guide member is formed of an insulator and a plurality of ribs on which the sheet slides, and is provided between the ribs and formed of a conductor, and the guide member is formed of an electrostatic material. And a transport guide plate that is grounded so as to be attracted.

Further, according to the present invention, there is provided a transport path for transporting the sheet to the fixing unit with the surface opposite to the toner image transfer surface facing upward, and the guide member includes a toner image transfer surface of the sheet. And is arranged above the transport path so as to adsorb the surface on the opposite side.

Further, the invention is characterized in that the transport guide plate is provided with an opening for sucking air.

Further, the invention is characterized in that the guide member is provided on the apparatus main body so as to be openable and closable.

Further, the present invention is characterized in that the guide member forms a part of an exterior of the apparatus main body.

Further, as in the present invention, a guide member for guiding the sheet on which the toner image has been transferred to the fixing portion is provided between the fixing portion and the transfer portion, and the guide member charges the toner image when transferring the toner image. The sheet opposite to the toner image transfer surface is conveyed toward the fixing unit with the surface opposite to the toner image transfer surface facing upward while electrostatically adsorbing the sheet.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a full-color laser beam printer which is an example of an image forming apparatus according to a first embodiment of the present invention.

In FIG. 1, reference numeral 100 denotes a full-color laser beam printer (hereinafter, referred to as LBP). The LBP 100 includes an image forming unit 101 and a paper feeder for feeding a transfer material S as a sheet to the image forming unit 101. Part 17
And a fixing unit 20 for fixing the toner image formed on the sheet by the image forming unit 101 to the transfer material S.

Here, the image forming unit 101 includes four photosensitive drums 1 (1
a, 1b, 1c, 1d) and a contact-charging type charging device 2 (2a, 2b, 2d) for uniformly charging the surface of the photosensitive drum 1.
2c, 2d), a scanner unit 3 (3a, 3b, 3c, 3d) for irradiating a laser beam based on image information to form an electrostatic latent image on the photosensitive drum 1, and a toner for the electrostatic latent image. A developing device 4 (4a, 4b, 4c, 4d) for developing a toner image by attaching
An electrostatic transfer device 5 constituting a transfer unit for transferring the upper toner image onto a transfer material S, and a photosensitive drum 1 after the transfer of the toner image
Cleaning device 6 (6a, 6b, 6c, 6d) for removing the transfer residual toner remaining on the surface of the printer.

In this embodiment, the photosensitive drum 1, the charging device 2, the developing device 4, and the cleaning device 6 are used.
Are integrated into a cartridge to form a process cartridge 7 (7a, 7b, 7c, 7d).

On the other hand, in the present embodiment, the photosensitive drum 1 (1a, 1b, 1c, 1d) has a diameter of, for example, 30 m.
m photoconductive layer (OPC)
(Photoconductor). The photosensitive drum 1 (1a, 1b, 1c, 1d) is rotatably supported at both ends by supporting members, and a driving force from a driving motor (not shown) is transmitted to one end. As a result, it is driven to rotate counterclockwise.

The charging device 2 (2a, 2b, 2c, 2
d) is a conductive roller 21 (21a, 2a) as a charging member.
1b, 21c, and 21d), the conductive roller 21 is brought into contact with the surface of the photosensitive drum 1, and a charging bias voltage is applied to the conductive roller 21 to clean the surface of the photosensitive drum 1. In the same way.

The scanner unit 3 includes a laser diode (not shown) and a polygon mirror 9 (9a, 9b, 9b, 9b, 9b, 9b) which are arranged in a substantially horizontal direction of the photosensitive drum 1 and are rotated at a high speed by a scanner motor (not shown). 9c, 9
d) and the imaging lens 10 (10a, 10b, 10c, 1)
0d).

The scanner unit 3 irradiates the image light corresponding to the image signal to the polygon mirror 9 rotating at a high speed by a laser diode, reflects the image light by the polygon mirror 9, and further reflects the reflected light. By selectively exposing the charged photosensitive drum surface through the imaging lens 10, an electrostatic latent image is formed on the photosensitive drum surface.

The developing device 4 includes toner containers 41 (41a, 41b, 41c, 41d) containing toners of yellow, magenta, cyan, and black, respectively.
Developing rollers 42 (42a, 42b, 42c,
42d).

The electrostatic transfer device 5 includes an electrostatic transfer belt 11 circulating and moving so as to face and contact all of the photosensitive drums 1 (1a, 1b, 1c, 1d).
And the electrostatic transfer belt 11
Transfer roller 12 (12a, 12b, 1)
2c, 12d).

Here, the electrostatic transfer belt 11 is formed of a film-shaped member having a peripheral length of 700 mm and a thickness of 150 μm having a volume resistivity of, for example, 10 ¹¹ to 10 ¹⁴ Ω · cm. The electrostatic transfer belt 11 has four rollers arranged in the vertical direction, that is, the support driving roller 1.
3. The transfer member S is vertically wound around the first driven roller 14a, the second driven roller 14b, and the tension roller 15, and is rotated in the direction of the arrow while electrostatically adsorbing the transfer material S to the outer peripheral surface on the left side in the figure. It has become.

In FIG. 1, reference numeral 22 denotes an electrostatic attraction roller which presses against the outer periphery of the electrostatic transfer belt 11, and the transfer material S is sandwiched between the electrostatic attraction roller 22 and the electrostatic transfer belt 11; By applying a voltage between the electrostatic attraction roller 22 and the electrostatic transfer belt 11, electric charges are induced in the transfer material S as a dielectric and the dielectric layer of the electrostatic transfer belt 11, and the transfer material S becomes static. It is configured to be electrostatically attracted to the outer periphery of the electrotransfer belt 11. By electrostatically attracting the transfer material S to the electrostatic transfer belt 11 in this manner, the transfer material S can be stably transported to the position of the most downstream photosensitive drum 1d.

On the other hand, the transfer roller 12 is
1, a negative charge is applied to the transfer material S through the transfer member 1. The negative charge toner image on the photosensitive drum 1 is transferred to the transfer material S in contact with the photosensitive drum 1 by an electric field generated by the charge. It is supposed to be.

Then, the electrostatic transfer device 5 having such a configuration is used.
When the electrostatic transfer belt 11 circulates so as to electrostatically attract the transfer material S to the outer peripheral surface and bring the transfer material S into contact with the photosensitive drum 1, the transfer material S
1 transfers the toner image on the photosensitive drum 1 to the transfer position.

The paper supply section 16 includes a paper supply cassette 17 for accommodating a plurality of transfer materials S, a paper supply roller (half moon roller) 18, a registration roller pair 19, and the like. During image formation, the paper feed roller 18 and the pair of registration rollers 19 are driven and rotated in accordance with the image forming operation, so that the transfer material S in the paper feed cassette 17 is separately fed one by one. In the case of such separation feeding, the transfer material S
Is stopped once after hitting the registration roller pair 19 to form a loop, and is fed to the electrostatic transfer belt 11 by the registration roller pair 19 by synchronizing the rotation of the electrostatic transfer belt 11 and the image writing position. It is going to go.

The fixing unit 20 fixes the toner images of a plurality of colors transferred to the transfer material S, and applies heat and pressure to the transfer material S by pressing against the rotating heating roller 21a. A fixing roller pair 21 including a pressure roller 21b is provided. When the transfer material S onto which the toner image has been transferred passes through the fixing unit 20, the transfer material S is conveyed by the fixing roller pair 21 and is given heat and pressure, so that a plurality of color toner images are formed on the surface of the transfer material S. It has become established.

Next, the LBP 100 configured as described above will be described.
Will be described.

In the image forming operation, first, the four process cartridges 7 (7a, 7b, 7c, 7d) are sequentially driven in accordance with the print timing, and the photosensitive drum 1 rotates counterclockwise in accordance with the drive. When driven, the charging roller 2 applies a uniform charge to the peripheral surface of the photosensitive drum 1. Further, the scanner units 3 corresponding to the respective process cartridges 7 are sequentially driven, and an electrostatic latent image corresponding to the image signal is formed on the peripheral surface of the photosensitive drum 1 by the scanner unit 3.

Next, the developing roller 42 in the developing device 4 transfers the toner to the low potential portion of the electrostatic latent image, and
A toner image is formed (developed) on the peripheral surface. Then, at the timing when the leading end of the toner image on the peripheral surface of the most upstream photosensitive drum 1a is rotated and conveyed to the point facing the electrostatic transfer belt 11, printing of the transfer material S is performed on the point. The registration roller pair 19 starts rotating so that the start positions match, and the transfer material S is fed to the electrostatic transfer belt 11.

As a result, the transfer material S is transferred to the electrostatic attraction roller 2
2 and the electrostatic transfer belt 11, and is electrostatically attracted to the outer periphery of the electrostatic transfer belt 11 by a voltage applied between the electrostatic transfer belt 11 and the electrostatic attraction roller 22. With the rotation of 11, the photosensitive drum 1d is transported to the most downstream position. Then, while being conveyed in this manner, the toner image on each photoconductor drum 1 is sequentially transferred onto the transfer material S by an electric field formed between each photoconductor drum 1 and the transfer roller 12.

Next, the transfer material S onto which the four color toner images have been transferred in this manner is separated from the electrostatic transfer belt 11 by the curvature of the belt driving roller 13, and the fixing unit 20.
It is carried in. Thereafter, the transfer material S is transferred to the fixing unit 20.
After the toner image is heat-fixed, the sheet is ejected from the main body by the sheet ejection roller pair 23 from the sheet ejection section 24 with the image side down.

FIG. 2 shows such an LBP 100
3 is an enlarged view of the vicinity of the fixing unit. In the figure, reference numeral 30 denotes a fixing member which is disposed between the fixing unit 20 and the electrostatic transfer device 5 and which is a guide member for guiding the transfer material S to the fixing unit 20. It is a guide.

Here, as shown in FIG. 3, the fixing entrance guide 30 is provided with a plurality of transport guide ribs 30a formed of a mold as an insulator in the transport direction, and further, between these transport guide ribs 30a. Is grounded by being integrally formed of a thin sheet metal (having a thickness of 1 mm or less) as a conductor and being fixed to a fixing device frame (not shown) or an apparatus main body frame 100A (see FIG. 1) with screws 32. A transfer guide plate 31 is provided.

In the present embodiment, the transport guide rib 30a has a predetermined height h (usually 2) above the transport guide plate 31 so that the transfer material S does not contact the transport guide plate 31.
mm).

The fixing entrance guide 30 is provided with a transport path R3 extending vertically so as to transport the transfer paper S shown in FIG. 1 toward the fixing unit 20 with the surface opposite to the toner image transfer surface facing upward. It is arranged above.

By arranging the fixing entrance guide 30 having the above-described configuration at such a position, the toner image is charged during the transfer of the toner image, and after the toner images of four colors are transferred, the electrostatic transfer is performed. The transfer guide rib 30a is formed such that the transfer paper S separated from the belt 11 by the curvature is electrostatically attracted to the fixing entrance guide 30 on the surface opposite to the toner image transfer surface.
And can be conveyed toward the fixing unit 20 along the path.

As a result, even when the transfer material S is a thin material such as thin paper, the leading end of the transfer material hangs down by its own weight and does not collide with the heating roller 21a as shown by the dotted line in FIG. This can reliably lead to the nip of the fixing roller pair 21 of the fixing unit 20 without the need.

In the present embodiment, the electrostatic transfer device 5 is supported by the apparatus main body frame 100A by the roller shaft 14a1 of the first driven roller 14a so as to be openable and closable. When a jam occurs, the jam transfer can be easily performed by opening the electrostatic transfer device 5 as shown in FIG.

The provision of the transport path R3 extending in the vertical direction as described above makes the configuration of the entire apparatus compact, and the jam can be cleared by simply opening the exterior, thereby simplifying the configuration. Also, usability will be significantly improved. Further, the cost can be considerably reduced as a whole.

Next, a second embodiment of the present invention will be described.

FIG. 5 is a diagram showing a configuration of a multicolor image forming apparatus as an example of the image forming apparatus according to the present embodiment. In FIG. 5, reference numeral 120 denotes a multicolor image forming apparatus, 51 denotes a photosensitive drum, 52 is a charging device, 53 is an exposure unit, 54 is a developing unit 54Y for yellow, magenta, cyan and black.
A developing device provided with 54M, 54C and 54Bk, and 55a is an intermediate transfer belt.

Reference numeral 55j denotes a pressing roller (primary transfer roller), and reference numeral 50 denotes a secondary transfer constituting a transfer portion provided at a predetermined position outside the intermediate transfer belt 55a so as to be able to contact and separate from the intermediate transfer belt 55a. The roller 56 is an intermediate transfer belt 5
The charging roller 56 of the cleaning unit is provided at a predetermined outside position of the cleaning unit 5a so as to be able to contact and separate from the intermediate transfer belt 55a.

Further, 57 is a transfer material stacking means, 58 is a pickup roller, 59 is a retard roller, 60 is a feed roller, 61 is a pair of registration rollers, 62 is a pre-registration sensor disposed immediately before the pair of registration rollers 61, and 65 is a sensor. A fixing device that constitutes a fixing unit, and includes a heating roller 65a and a pressure roller 6 that presses against the heating roller 65a to apply heat and pressure to the transfer material S.
5b is provided. Reference numeral 66 denotes a discharge roller pair, and 67 denotes a discharge tray.

Next, an image forming operation in the multi-color image forming apparatus thus configured will be described.

In forming an image, first, the intermediate transfer belt 55a
The photosensitive drum 51 is rotated in the direction of the arrow (clockwise) in FIG. 3 in synchronization with the rotation of the photosensitive drum 51, and the surface of the photosensitive drum 51 is uniformly charged by the charging device 52. Is performed to form a yellow electrostatic latent image on the photosensitive drum 51.

Further, simultaneously with the formation of the electrostatic latent image, the developing device 54 is driven to arrange the yellow developing device 54Y at the developing position so that the yellow toner adheres to the electrostatic latent image on the photosensitive drum 51. A voltage having the same polarity and substantially the same potential as the charging polarity of the photosensitive drum 51 is applied to cause the yellow toner to adhere to the electrostatic latent image for development. Thereafter, the intermediate transfer belt 5
A yellow toner image on the photosensitive drum 51 is primary-transferred onto the intermediate transfer belt 55a by applying a voltage having a polarity opposite to that of the toner to the pressing roller (primary transfer roller) 55j of No.5.

Next, when the primary transfer of the yellow toner image is completed in this manner, the formation, development, and development of an electrostatic latent image for each of the colors magenta, cyan, and black are performed similarly to the case of yellow. The primary transfer is sequentially performed, and the toner images of four colors are superimposed on the intermediate transfer belt 55a.

While the four color toner images are formed on the intermediate transfer belt 55a, the secondary transfer roller 5
0 is in a non-contact state with the intermediate transfer belt 55a, and the charging roller 56 of the cleaning unit
5a is in a non-contact state. During this time, the transfer material S stored in the transfer material loading means 57 is supplied to the pickup roller 58, the retard roller 59, and the feed roller 60.
, The sheet is fed one by one, and stands by at a predetermined position near the pair of registration rollers 61.

Next, the intermediate transfer belt 55
After the four color toner images are formed on the intermediate transfer belt 55a, the secondary transfer roller 50 is pressed against the intermediate transfer belt 55a. Further, the transfer material S waiting at a predetermined position near the registration roller pair 61 is synchronized with the rotation of the intermediate transfer belt 55a based on the detection signal from the pre-registration sensor 62.
a and the secondary transfer roller 50.

Here, a voltage having a polarity opposite to that of the toner is applied to the secondary transfer roller 50, whereby the toner image on the intermediate transfer belt 55a is transferred to the transferred transfer material S.
Is secondarily transferred to the surface of the sheet at a time.

After the secondary transfer is performed on the transfer material S in a lump, the cleaning unit brings the charging roller 56 into contact with the intermediate transfer belt 55a to apply a charge to the toner which is opposite to that at the time of transfer. Then, the toner having the opposite charge is electrostatically attached to the photosensitive drum 51, and thereafter, is collected by a cleaning device (not shown) of the photosensitive drum 51, and the remaining transfer residual toner is removed. The method of cleaning the intermediate transfer belt 55a is not limited to the electrostatic cleaning described above, but may be a mechanical method such as a blade or a fur brush, or a method using both of them.

Finally, the transfer material S secondary-transferred in this way reaches a fixing device 65, where a plurality of color toner images are fixed, and then discharged and conveyed by a discharge roller pair 66. Then, the sheet is discharged to the sheet discharge tray 67 at the top of the image forming apparatus, and the image forming operation is completed.

In the figure, reference numeral 63 denotes a guide member disposed between the secondary transfer roller 50 and the fixing device 65 and for directing the secondary-transferred transfer material S to the fixing device 65. The conveyance guide 63
Is provided with a plurality of transport guide ribs 63a which are formed of a mold as an insulator.

Further, between the transport guide ribs 63a,
As shown in FIG. 3 described above, a transport guide plate 64 integrally formed of a thin sheet metal (having a thickness of 1 mm or less) as a conductor and grounded to the multicolor image forming apparatus main body 120A is provided. In the present embodiment, the transport guide rib 63a is formed to be higher than the transport guide plate 64 by a predetermined height h (usually about 2 mm) so that the transfer material S does not contact the transport guide plate 64. .

The transport guide 63 has a transport path R4 extending in a substantially horizontal direction so as to transport the transfer paper S shown in the figure toward the fixing device 65 with the surface opposite to the toner image transfer surface facing upward. It is arranged above.

By arranging the transport guide 63 having the above-described configuration at such a position, the toner image is charged at the time of transferring the toner image and the four color toner images are transferred. Paper S whose curvature is separated from
Can be transported toward the fixing device 65 along the transport guide rib 63a while electrostatically attracting the surface opposite to the toner image transfer surface to the transport guide 63.

Accordingly, even when the transfer material S is a thin material such as a thin paper, the leading end of the transfer material hangs down by its own weight and does not collide with the heating roller 65a, that is, the fixing roller of the fixing unit 65 does not cause a jam. It is possible to reliably lead to the nip of the pair 65.

In this embodiment, the transport guide 63 is disposed above the transport route R4 and constitutes a part of the exterior of the apparatus main body frame 120A. The transport guide plate 64 is provided with a fan F, and has an opening (not shown) for air suction. The transfer material S can be transported more reliably by adsorbing the transfer material S by the fan F. Further, the transport guide 63 is supported by the apparatus main body frame 120A so as to be freely opened and closed by a rotating shaft 63a. When the transfer material S is jammed in the transfer portion or the fixing device 65, the jam can be easily removed by opening the transport guide 63 as shown by the broken line in FIG. In addition, by performing the jam clearance by simply opening the exterior, the configuration is simplified and usability is significantly improved.

[0068]

As described above, according to the present invention, a guide member is provided between a fixing unit and a transfer unit, and the sheet is electrostatically attracted to the opposite side of the toner image transfer surface by the guide member. The paper is conveyed toward the fixing unit with its surface facing upward, so that even transfer paper such as a thin paper sheet can be reliably guided to the fixing unit.

[Brief description of the drawings]

FIG. 1 illustrates a full-color laser beam printer (LB) as an example of an image forming apparatus according to a first embodiment of the present invention.
The figure which shows the structure of P).

FIG. 2 is an enlarged view of the vicinity of a fixing portion of the LBP.

FIG. 3 is a diagram showing a configuration of a fixing entrance guide provided in the LBP.

FIG. 4 is a view for explaining jam processing in the LBP.

FIG. 5 is a diagram illustrating a configuration of a multicolor image forming apparatus as an example of an image forming apparatus according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration of a conventional multicolor image forming apparatus.

FIG. 7 is a diagram showing another configuration of a conventional multicolor image forming apparatus.

[Explanation of symbols]

 1 (1a, 1b, 1c, 1d) photosensitive drum 4 (4a, 4b, 4c, 4d) developing device 5 electrostatic transfer device 11 electrostatic transfer belt 20 fixing unit 30 fixing inlet guide 30a transport guide rib 31 transport guide plate 50 Secondary transfer roller 51 Photoreceptor drum 54 Developing device 55a Intermediate transfer belt 63 Transport guide 63a Transport guide rib 64 Transport 100 guide plate 65 Fixing unit 100 LBP 101 Image forming unit 120 Multicolor image forming device S Transfer paper

Claims (9)

[Claims] 1. An image forming apparatus wherein a toner image formed by developing a latent image on an image carrier is transferred to a sheet and then fixed on the sheet, wherein the transfer of the toner image to the sheet is performed. A fixing unit that is provided above the transfer unit and fixes the toner image transferred to the sheet onto the sheet; a fixing unit that is provided between the fixing unit and the transfer unit; A guide member for guiding the toner image, wherein the sheet is charged toward the fixing unit while electrostatically attracted by the guide member while the toner image is transferred. apparatus. 2. The guide member is formed of an insulator and a plurality of ribs on which the sheet slides, and is provided between the ribs and formed of a conductor, and electrostatically attracts the sheet. The image forming apparatus according to claim 1, further comprising: a conveyance guide plate grounded so as to perform the operation. 3. A transport path for transporting the sheet toward the fixing unit with the surface opposite to the toner image transfer surface facing upward, wherein the guide member is on the opposite side of the sheet from the toner image transfer surface. The image forming apparatus according to claim 1, wherein the image forming apparatus is arranged above the transport path so as to suck the surface. 4. An image forming apparatus in which a toner image formed by developing a latent image on an image carrier is transferred to a sheet, and then fixed on the sheet, wherein the toner image is transferred to the sheet. A fixing unit for fixing the toner image transferred to the sheet to the sheet; and a guide member provided between the fixing unit and the transfer unit, for guiding the sheet to the fixing unit. An image forming apparatus configured to convey the toner image to the fixing unit with the toner image transfer surface facing downward while electrostatically adsorbing the sheet charged during transfer of the toner image by the guide member; . 5. The guide member is formed of an insulator and a plurality of ribs on which the sheet slides, and is provided between the ribs and formed of a conductor, and electrostatically attracts the sheet. The image forming apparatus according to claim 4, further comprising: a conveyance guide plate grounded so as to perform the operation. 6. A transport path for transporting the sheet toward the fixing unit with the surface opposite to the toner image transfer surface facing upward, wherein the guide member is located on a side opposite to the toner image transfer surface of the sheet. The image forming apparatus according to claim 4, wherein the image forming apparatus is disposed above the transport path so as to suck the surface. 7. The transport guide plate is provided with an opening for sucking air.
The image forming apparatus according to any one of the above. 8. The image forming apparatus according to claim 1, wherein the guide member is provided on the apparatus main body so as to be openable and closable. 9. The image forming apparatus according to claim 8, wherein the guide member forms a part of an exterior of the apparatus main body.