JP2003084514A - Image forming apparatus and guide contact preventing roll arranged on downstream side of fixing device for image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of a defective image due to rubbing of a toner image on a recording sheet against a sheet guide on the downstream side of a fixing device. SOLUTION: The image forming apparatus is provided with a sheet carrying device US equipped with a sheet guide for guiding the recording sheet a and for successively carrying the recording sheet S to a transfer area Q4 and a fixation area Q5, a toner image forming device PR+CR+G+T1+B+T2 for forming the toner image on the recording sheet S passing through the transfer area Q4, a fixing device F for thermally fixing the toner image on the recording sheet S passing through the fixation area Q5, a fixing device downstream side sheet guide 10 arranged on the downstream side of the fixing device F, and a guide contact preventing roll arranged so as to come into contact with the toner image forming surface of the recording sheet S in order to prevent the recording sheet S from coming into contact with a rib.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying machine for faxing a toner image transferred onto a recording sheet by heating and fixing it.
(Facsimile), image forming apparatus such as printer, and sheet guide for the image forming apparatus, and particularly to an image forming apparatus and a fixing device downstream of the image forming apparatus, in which an image defect does not occur in a toner image fixed on a recording sheet It relates to a guide contact prevention roll arranged on the side.

[0002]

2. Description of the Related Art A toner image on a recording sheet may be scratched or change in gloss when rubbed against a sheet guide, and in that case, an image defect may occur. Conventional techniques for preventing this image defect are described in, for example, the following publications (J01) and (J02). (J01) Japanese Patent Laid-Open No. 5-80615 This publication describes a technique for preventing the occurrence of rubbing, seat bending, etc. by keeping the sheet traveling posture within a certain range by varying the conveying speed on the downstream side in the sheet conveying direction. Has been done. Further, a driven roll 15B supported on a swingable supporting member 19 capable of swinging for adjusting the spread state of the paper is described. (J02) Japanese Unexamined Patent Publication No. 9-114153 This publication describes a technique in which the position of the movable guide roller is changed by the tensile force applied to the transfer sheet to form an ideal transport path. .

[0003]

(Problems of (J01)) The method described in (J01) requires means for detecting the running posture of the recording sheet and means for increasing / decreasing the speed. In addition, a space for providing the swing support member is required, which complicates the structure and increases the number of parts.

(Problem of (J02)) In the configuration described in (J02), since the image surface of the recording sheet is pressed against the sheet guide, image rubbing by the sheet guide cannot be prevented.

In view of the above-mentioned circumstances, the present invention has the following contents (O01). (O01) It is possible to prevent the occurrence of an image defect due to the friction between the toner image on the recording sheet and the sheet guide on the downstream side of the fixing device with a simple configuration.

[0006]

The present invention devised to solve the above problems will now be described. The elements of the present invention facilitate the correspondence with the elements of the embodiments described later. Therefore, the reference numerals of the elements of the embodiment enclosed in parentheses are added. Further, the reason why the present invention is described in association with the reference numerals of the embodiments described below is to facilitate understanding of the present invention and not to limit the scope of the present invention to the embodiments.

(Invention) In order to solve the above-mentioned problems, the image forming apparatus of the present invention has the following constitutional requirements (A01) to (A0).
It is characterized by having 5). (A01) A sheet conveying device (US) having a sheet guide that guides the upper surface or the lower surface of the recording sheet (S) and sequentially conveying the recording sheet (S) to the transfer area (Q4) and the fixing area (Q5), (A02) Toner image forming apparatus (PR + CR + G + T1 + B + T2) for forming a toner image on the recording sheet (S) passing through the transfer area (Q4), (A0
3) Recording sheet (S) that passes through the fixing area (Q5)
Fixing device (F), (A05) for fixing the above toner image by heating
Ribs (1) arranged on the downstream side of the fixing device (F) and on the contact surface with the recording sheet (S) along the sheet conveying direction.
1a) is formed on the sheet guide (1
0), (A06) Sheet guide (1) on the downstream side of the fixing device
0) the recording sheet (S) is the rib (11a)
A guide contact prevention roll (17) which is freely rotatable and arranged so as to come into contact with the toner image forming surface of the recording sheet (S) in order to prevent the contact with the toner image forming surface.

In the image forming apparatus of the present invention having the above structural requirements (A01) to (A06), the sheet conveying device (US) having a sheet guide for guiding the upper surface or the lower surface of the recording sheet (S) is the recording apparatus. Transfer the sheet (S) to the transfer area (Q
4) and sequentially conveys to the fixing area (Q5). The toner image forming device (PR + CR + G + T1 + B + T2) forms a toner image on the recording sheet (S) passing through the transfer area (Q4). The fixing device (F) has a recording fixing area (Q5).
The toner image on the recording sheet (S) passing through is fixed by heating. The freely rotatable guide contact prevention roll disposed so as to come into contact with the toner image forming surface of the recording sheet (S) has the recording sheet (S) passing through the sheet guide (10) on the downstream side of the fixing device and the sheet on the downstream side of the fixing device. Prevent contact with the guide (10). The toner image on the recording sheet (S) does not come into contact with or rub against the surface of the sheet guide (10) on the downstream side of the fixing device, so that no image defect occurs.

Further, the image forming apparatus of the present invention is characterized in that, in the image forming apparatus having the above-mentioned structural requirements (A01) to (A05), the following structural requirements (A06) and (A07) are provided. . (A06) is arranged on the downstream side of the fixing device (F), and
A fixing device downstream side sheet guide (10) having ribs (11a) formed on the contact surface with the recording sheet (S) along the sheet conveying direction, (A07) the fixing device (F) downstream side sheet guide (10) By a freely rotatable guide contact prevention roll (17) arranged so as to come into contact with the toner image forming surface of the recording sheet (S) in order to prevent the recording sheet (S) passing through the sheet from coming into contact with the rib (11a). The formed guide contact prevention roll (17).

In the image forming apparatus having the above-mentioned structural requirements (A06) and (A07), the freely rotatable guide contact prevention roll (17) disposed so as to be in contact with the toner image forming surface of the recording sheet (S) is Sheet guide (1
It prevents the recording sheet (S) passing through (0) from coming into contact with the rib (11a) of the sheet guide (10) on the downstream side of the fixing device. The toner image on the recording sheet (S) does not come into contact with the surface of the rib (11a) and is not rubbed, so that no image defect occurs.

Further, the image forming apparatus of the present invention is characterized in that the image forming apparatus having the above-mentioned constitutional requirements (A01) to (A07) is provided with the following constitutional requirements (A08) and (A09). . (A08) A drive roll (16) for applying a conveying force to the recording sheet (S) passing through the sheet guide on the downstream side of the fixing device.
a) and a transport roll (1) on the downstream side of the fixing device, which has a driven roll (16b) in pressure contact with the drive roll (16a).
6), (A09) Transport roller (16) on the downstream side of the fixing device
Mounted on the shaft of the driven roll and driving roll (16
The guide contact prevention roll (17) composed of a driven roll that does not come into pressure contact with a).

In the image forming apparatus having the above-mentioned structural requirements (A08) and (A09), the conveying roll (downstream) of the fixing device having the drive roll (16a) and the driven roll (16b) in pressure contact with the drive roll (16a) ( 16) applies a conveying force to the recording sheet (S) passing through the sheet guide (10) on the downstream side of the fixing device. The guide contact prevention roll (17) is a driven roll which is mounted on the shaft of the driven roll (16b) of the fixing device downstream side transport roll (16) and which is not in pressure contact with the drive roll (16a). The recording sheet (S) is provided without newly securing a space for disposing the guide contact prevention roll (17) or newly providing a support structure for supporting the guide contact prevention roll (17). It is possible to prevent the upper toner image from contacting or rubbing the surface of the rib (11a).

Further, the guide contact prevention roll arranged on the downstream side of the fixing device of the image forming apparatus of the present invention is characterized by having the following constituent requirements (A010). (A010) Ribs (11) are arranged on the downstream side of the fixing area (Q5) and along the conveyance direction of the recording sheet (S).
In order to prevent the recording sheet (S) passing through the sheet guide (11) on which the a) is formed from coming into contact with the ribs (11a), the recording sheet (S) is arranged so as to be in contact with the toner image forming surface of the recording sheet (S). Freely rotating guide contact prevention roll (1
7).

The freely rotatable guide contact prevention roll (17) arranged downstream of the fixing area having the above-mentioned constituent requirements (A010) and contactable with the toner image forming surface of the recording sheet is the recording sheet. This prevents the recording sheet (S) passing through the sheet guide (10) having the rib (11a) formed along the conveyance direction of (S) from coming into contact with the rib (11a). Therefore, it is possible to prevent the toner image on the recording sheet (S) from coming into contact with or rubbing the surface of the rib (11a).

Further, the guide contact prevention roll arranged on the downstream side of the fixing device of the image forming apparatus of the present invention is characterized by having the following constituent requirements (A011). (A011) The guide contact prevention roll (17) made of a foam material. Since the guide contact prevention roll (17) having the constituent requirement (A011) is made of a foam material, it may damage the fixed toner image even if the fixed toner image of the recording sheet (S) contacts. Absent.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, specific examples (embodiments) of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples. (Embodiment) FIG. 1 is an explanatory view of an image forming apparatus in which a developer cartridge of an embodiment of the image forming apparatus of the present invention is mounted. 2A and 2B are explanatory views of the main part shown in FIG. 1, FIG. 2A is an enlarged view of the main part of FIG. 1, and FIG. 2B is a perspective view of a downstream side portion of the fixing device, which is the main part shown in FIG. 2A. Is.
In FIGS. 1 and 2, an automatic document feeder U2 is placed on the upper surface of the platen glass PG at the upper end of the image forming apparatus U1 constituted by a copying machine. The automatic document feeder U2 has a document feed tray TG1 on which a plurality of documents Gi to be copied are stacked and placed. Each of the plurality of documents Gi placed on the document feed tray TG1 is configured to sequentially pass through the copy position on the platen glass PG and be discharged to the document discharge tray TG2. The automatic document feeder U2 is rotatable with respect to the copying machine U1 by a hinge shaft (not shown) extending in the left-right direction provided at a rear end portion (-X end portion) of the original document Gi. Is rotated upward when it is placed on the platen glass PG by hand.

The image forming apparatus U1 has a UI (user interface) through which the user inputs and operates an operation command signal such as copy start. The IIT as an original reading device arranged below the transparent platen glass PG on the upper surface of the image forming apparatus U1 includes an exposure system registration sensor (platen registration sensor) Sp arranged at a platen registration position (OPT position) and an exposure optical system A. have. The exposure optical system A has an exposure system registration sensor S for moving and stopping.
It is controlled by the detection signal of p and always stops at the home position. Reflected light from the document Gi that has passed the exposure position on the upper surface of the platen glass PG by the automatic document feeder U2 or a document manually placed on the platen glass PG is transmitted through the exposure optical system A to a CCD (solid-state imaging device). It is converted into R (red), G (green), and B (blue) electric signals by the element.

An IPS (image processing system) temporarily converts the RGB electrical signals input from the CCD into image data of K (black), Y (yellow), M (magenta), and C (cyan). And outputs the image data to the laser drive circuit DL as image data for forming a latent image at a predetermined timing. Laser drive circuit D
L outputs a laser drive signal to ROS (latent image forming device) according to the input image data. The operations of the IPS and the laser drive circuit DL are controlled by a controller C composed of a microcomputer.

The image carrier PR is rotating in the direction of the arrow Ya, and its surface is uniformly charged by the charger (charge roll) CR, and then at the latent image writing position Q1, the ROS (latent An electrostatic latent image is formed by exposure scanning with a laser beam L of an image forming apparatus). When forming a full-color image, electrostatic latent images corresponding to four-color images of K (black), Y (yellow), M (magenta), and C (cyan) are sequentially formed, and in the case of a monochrome image, K is formed. Only the electrostatic latent image corresponding to the (black) image is formed.

The surface of the image carrier PR on which the electrostatic latent image is formed is rotationally moved and sequentially passes through the developing area Q2 and the primary transfer area Q3. The rotary type developing device G sequentially rotates and moves to the developing area Q2 as the rotation shaft Ga rotates.
It has four color developing units GK, GY, GM and GC of (black), Y (yellow), M (magenta) and C (cyan). The developing units GK, GY, GM, and GC of the respective colors have a developing roll GR that conveys the developer to the developing area Q2, and form an electrostatic latent image on the image carrier PR passing through the developing area Q2. Develop into a toner image. Each of the developing units GK, GY,
The cartridge mounting portions Hk and H are provided on the developing containers of GM and GC.
Toners of respective colors are replenished from the toner replenishing cartridges mounted on y, Hm, and Hc (see FIG. 1). In addition, such a rotary type developing device,
For example, JP-A-12-131942 and JP-A-12-23
1250 and the like.

Below the image carrier PR, an intermediate transfer belt B, a belt driving roll Rd and a tension roll R are provided.
t, a walking roll Rw, an idler roll (free roll) Rf, and a plurality of belt support rolls (Rd, Rt, Rw, Rf, T2) including a backup roll T2a.
a), a primary transfer roll T1, and a belt frame (not shown) that supports them. Further, the intermediate transfer belt B has the belt supporting rolls (Rd, R
It is rotatably supported by t, Rw, Rf, T2a) and rotates in the direction of the arrow Yb during the operation of the image forming apparatus.

When forming a full-color image, the electrostatic latent image of the first color is formed at the latent image writing position Q1, and the toner image Tn of the first color is formed in the developing area Q2.
The toner image Tn is electrostatically primarily transferred onto the intermediate transfer belt B by the primary transfer roll T1 when passing through the primary transfer area Q3. Thereafter, in the same manner, the second image is transferred onto the intermediate transfer belt B carrying the first color toner image Tn.
The toner images Tn of the colors, the third color, and the fourth color are sequentially superposed and primary-transferred, and finally a full-color multiple toner image is formed on the intermediate transfer belt B. When forming a monochromatic monocolor image, only one developing device is used, and the monochromatic toner image is primarily transferred onto the intermediate transfer belt B. After the primary transfer, the surface of the image carrier PR is subjected to static elimination of residual toner by the static eliminator JR and cleaned by the image carrier cleaner CL1.

Below the backup roll T2a, a secondary transfer roll T2b is provided with the backup roll T2.
It is movably arranged between a position separated from 2a and a position in contact therewith. The backup roll T2a
The secondary transfer roll T2b constitutes a secondary transfer device T2. The backup rolls T2a and 2
The secondary transfer area Q4 depends on the contact area of the secondary transfer roll T2b.
Are formed. A secondary transfer voltage having a polarity opposite to the charging polarity of the toner used in the developing device G is supplied from the power supply circuit E to the secondary transfer roll T2b, and the power supply circuit E is controlled by the controller C.

The recording sheets S accommodated in the paper feed tray TR1 or TR2 are taken out by a pickup roll Rp at a predetermined timing, separated one by one by a separating roll Rs, and are conveyed by a plurality of transport rolls Ra in the paper feed path SH1. Is conveyed to the registration roll Rr. The cash register roll Rr
The recording sheet S conveyed to the pre-transfer sheet guide S is timed to move the primary-transferred multiple toner image or single-color toner image to the secondary transfer area Q4.
The sheet is conveyed from G1 to the secondary transfer area Q4. In the secondary transfer area Q4, the secondary transfer device T2 electrostatically secondarily transfers the toner image on the intermediate transfer belt B onto the recording sheet S. The intermediate transfer belt B after the secondary transfer is a belt cleaner C.
The residual toner is removed by L2. The image carrier P
R, charging roll CR, developing device G, sustain transfer roll T
A toner image forming apparatus (PR + CR + G + T1 + B + T2) that transfers and forms a toner image on the recording sheet S is configured by the intermediate transfer belt B, the secondary transfer device T2, and the like.

Incidentally, the secondary transfer roll T2b and the belt cleaner CL2 are arranged so as to be able to come into contact with (separate from and contact with) the intermediate transfer belt B, and when the color image is formed, the final color is undetermined. The toner image is separated from the intermediate transfer belt B until it is primarily transferred to the intermediate transfer belt B. The secondary transfer roll cleaner CL3
Moves to and from the intermediate transfer belt B together with the secondary transfer roll T2b. The recording sheet S to which the toner image is secondarily transferred is conveyed to the fixing area Q5 by the post-transfer sheet guide SG2 and the sheet conveying belt BH. The fixing region Q5 is a region (nip) where the heating roll Fh and the pressure roll Fp of the fixing device F are in pressure contact with each other, and the fixing region Q5
The recording sheet S passing through is fixed by heating by the fixing device F.

In FIG. 1, a sheet conveying roll Rb having a driving roll Rb1 and a driven roll Rb2 and a sheet discharge path SH2 are provided on the downstream side of the fixing area Q5 for fixing the toner image on the recording sheet S. A sheet inverting path SH3 is connected to the discharge path SH2. A switching gate GT1 is provided at a branch point of the sheet discharging path SH2 and the sheet inverting path SH3. The recording sheet S conveyed to the sheet discharge path SH2 is conveyed to the sheet discharge roller Rh by a plurality of conveying rollers Ra, and is discharged to the sheet discharge tray TR3 from the sheet discharge port Ka formed at the upper end of the image forming apparatus U1. It The sheet inversion path SH3
Is connected to a sheet circulation path SH4, and a mylar gate GT2 composed of a sheet-like member is connected to the connection portion.
Is provided. The mylar gate GT2 allows the recording sheet S conveyed through the sheet inversion path SH3 from the switching gate GT1 to pass through as it is, and the recording sheet S that has once passed and then switched back is directed to the sheet circulation path SH4 side. Dodge The recording sheet S conveyed to the sheet circulation path SH4 is retransmitted to the transfer area Q4 through the paper feed path SH1. The symbols SH1 to SH4
The sheet conveying path SH is constituted by the elements indicated by. A sheet conveying device US is constituted by the sheet conveying path SH and rollers Ra, Rh, RP, etc., which have a sheet conveying function arranged therein.

In FIGS. 1 and 2, the fixing device F has an outer wall 1 and an inner wall 2, and a suction duct 3 is formed between the outer wall 1 and the inner wall 2. The suction duct 3 is configured to be sucked by a fan (not shown) provided on the rear side (−X side) of the fixing device F to discharge high temperature air around the fixing device. Inside the inner side wall 2, a cylindrical oil applying member 4 for applying the sheet peeling oil to the surface of the heating roll Fh is supported, and an oil wiping member 5 for wiping off the oil on the surface of the heating roll Fh. Is supported. Sheet guides 7a and 7b are arranged on the upstream side of the pressure contact area Q5 of the heating roll Fh and the pressure roll Fp of the fixing device F in the sheet conveying direction. A sheet lower surface guide 9 that guides the lower surface of the recording sheet S is arranged on the downstream side of the fixing area Q5, and a fixing device downstream side sheet guide 10 is arranged on the downstream side of the sheet lower surface guide 9. . The sheet guide 10 on the downstream side of the fixing device has a pair of upper and lower sheet guides 11 and 12, and the upper sheet guide 11 has a plurality of ribs 11a arranged at intervals in the front-rear direction and four blower openings. 11b. The lower sheet guide 12 has a plurality of ribs 12a.

FIG. 3 is a detailed explanatory view of a sheet guide, a sheet conveying drive roll, a driven roll (pinch roll), and a guide contact prevention roll arranged on the downstream side of the fixing device. It is a figure. 2 and 3
The ribs 11 on the lower surface of the upper sheet guide 11
The letter a is arranged at a position where the toner image forming surface of the high temperature recording sheet S immediately after passing through the fixing device comes into contact. The fixing device downstream side transport roll 16 includes a drive roll 16a and a drive roll 16a for imparting a transport force to the recording sheet S passing through the fixing device downstream side sheet guide 10.
It has a driven roll 16b that is in pressure contact with. The dummy roll 17 as a guide contact prevention roll is rotatably mounted on the shaft of the driven roll 16b of the fixing device downstream side transport roll 16, and the drive roll 16a that is in pressure contact with the dummy roll 17 is not provided. . That is,
The dummy roll 17 does not have a sheet conveying function, but has a function of preventing the toner image forming surface of the recording sheet S passing through the sheet guide 10 on the downstream side of the fixing device from coming into contact with the rib 11a. .

(Operation of Embodiment) In the image forming apparatus of the embodiment of the present invention having the above-mentioned structure, the sheet conveying device US is
The recording sheet S is sequentially conveyed to the transfer area Q4 and the fixing area Q5. Toner image forming device (PR + CR + G + T1 +
B + T2) forms a toner image on the recording sheet S passing through the transfer area Q4. The fixing device F heats and fixes the toner image on the recording sheet S passing through the recording / fixing area Q5. The transport roll 16 on the downstream side of the fixing device is the drive roll 1.
6a and a driven roll 16b that is in pressure contact with the drive roll 16a, and applies a conveying force to the recording sheet S passing through the sheet guide 10 on the downstream side of the fixing device.

Since the dummy roll 17 is mounted coaxially with the driven roll 16b of the transport roll 16 on the downstream side of the fixing device, a space for arranging the dummy roll is newly secured or the dummy roll is not provided. It is possible to prevent the toner image on the recording sheet S from coming into contact with or rubbing the surface of the rib 11a without newly providing a supporting structure for supporting. Therefore, the toner image on the recording sheet S is formed on the rib 11a.
Since it does not come into contact with the surface and is not rubbed, no image defect occurs.

(Modification) The embodiment of the present invention has been described in detail above. However, the present invention is not limited to the above-mentioned embodiment, and the gist of the present invention described in the scope of claims is not limited. Various changes can be made within the range. A modified embodiment of the present invention will be exemplified below. (H01) The present invention can be applied to an image forming apparatus other than a copying machine, such as a printer or a FAX. (H02) The present invention can be applied to a sheet guide without ribs.

[0032]

The image forming apparatus of the present invention described above can achieve the following effects (E01). (E01) It is possible to prevent the occurrence of image defects due to the friction between the toner image on the recording sheet and the sheet guide with a simple configuration.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an image forming apparatus in which a developer cartridge of an embodiment of the image forming apparatus of the present invention is mounted.

FIG. 2 is an explanatory view of the main part shown in FIG.
FIG. 2A is an enlarged view of an essential part of FIG. 1, and FIG. 2B is a perspective view of a downstream side portion of the fixing device, which is an essential part shown in FIG. 2A.

FIG. 3 is a detailed explanatory view of a sheet guide, a sheet conveying drive roll, a driven roll (pinch roll), and a guide contact prevention roll, which are arranged on the downstream side of the fixing device.
FIG. 3 is a sectional view taken along line III-III of FIG. 2A.

[Explanation of symbols]

F ... Fixing device, Q4 ... Transfer area, Q5 ... Fixing area, S ...
Recording sheet, US ... Sheet conveying device, 10 ... Fixing device downstream side sheet guide, 11a ... Rib, 11 ... Sheet guide, 11a ... Rib, 11c ... Low friction material layer, 17 ... Guide contact prevention roll (dummy roll), ( PR + CR + G
+ T1 + B + T2) ... Toner image forming device,

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H072 CA01 CB07 CB08 JA02 JA04                       JC02 JC07                 3F049 CA16 CA31 DA12 LA02 LA05                       LA07 LB03                 3F101 FA02 FB07 FB08 FB11 FC05                       FD04 LA02 LA05 LA07 LB03

Claims (5)

[Claims] 1. An image forming apparatus having the following structural requirements (A01) to (A05), and (A01) a sheet guide for guiding the upper surface or the lower surface of a recording sheet, wherein the recording sheet is a transfer area or a fixing area. Sheet conveying device that sequentially conveys sheets to the
02) A toner image forming device for forming a toner image on a recording sheet passing through the transfer region, (A03) A fixing device for heating and fixing the toner image on the recording sheet passing through the fixing region, (A04) The fixing device (A05) Toner image formation on the recording sheet in order to prevent the recording sheet passing through the sheet guide on the downstream side of the fixing device from contacting with the sheet guide on the downstream side of the fixing device. A guide contact prevention roll that is freely rotatable and is arranged so that it can contact the surface. 2. An image forming apparatus according to claim 1, further comprising the following structural requirements (A06) and (A07), and (A06) a sheet which is arranged on the downstream side of the fixing device and which is in contact with a recording sheet. (A07) Toner image forming surface of the recording sheet for preventing a recording sheet passing through the sheet guide on the downstream side of the fixing device from coming into contact with the rib. A guide contact prevention roll that is free to rotate and is placed so that it can come into contact with. 3. The image forming apparatus according to claim 1 or 2, further comprising the following constituents (A08) and (A09), and (A08) imparting a conveying force to the recording sheet passing through the sheet guide on the downstream side of the fixing device. A fixing device downstream side transport roll having a drive roll for driving and a driven roll in pressure contact with the drive roll,
(A09) The guide contact prevention roll configured by a driven roll that is mounted on the shaft of the driven roll of the transport roll on the downstream side of the fixing device and that is not in pressure contact with the drive roll. 4. A guide contact prevention roll arranged on the downstream side of the fixing device of an image forming apparatus having the following constituent features (A010), and (A010) a guide contact prevention roll arranged on the downstream side of the fixing area and conveying the recording sheet. A freely rotatable guide contact prevention roll disposed so as to come into contact with a toner image forming surface of a recording sheet to prevent the recording sheet passing through a sheet guide having a rib formed along the direction from coming into contact with the rib. 5. A guide contact prevention roll disposed on the downstream side of the fixing device of the image forming apparatus according to claim 4, which comprises the following constituent requirements (A011), and (A011) the guide contact prevention roller made of a foam material. roll.