JP2000281241A - Recording material-transporting device and image- forming device using thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively guide a recording material to a fixing means without reducing an image-supporting region and developing a disturbed image in guiding the recording material transferred by means of a transferring means to as far as a fixing device. SOLUTION: A recording material-transporting device is disposed between a transferring means 2 for transferring an unfixed image to a recording material 4 and a fixing means 3 for fixing the unfixed image transferred to the recording material 4 and guides the recording material 4 toward the fixing means 3 from the transferring means 2. The recording material-transferring device has a guide member 1 abutted to only the end edge of the recording material 4 and for guiding the extreme position of the recording material 4 to a right projection position to the fixing means 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material conveying apparatus used for an image forming apparatus such as a printer, a copying machine, a facsimile, etc., and more particularly to a recording medium for conveying a recording material carrying an unfixed transfer image to a fixing means. The present invention relates to a material conveying device and an image forming apparatus used for the same.

[0002]

2. Description of the Related Art In recent years, technical improvements in printers and color copiers as computer outputs have been remarkable. One of them
There is a high demand for two-sided printing in order to make effective use of sheets of recording material. Further, in two-sided printing, improvement in output speed as well as image quality is strongly desired.

As a technique for performing double-sided printing, first, a toner image is transferred onto one side of a recording material and then temporarily fixed, and thereafter, the recording material is re-supplied to a transfer portion and a toner image is formed on the opposite surface of the recording material. A double-sided image forming apparatus for re-fixing after transferring is already provided. However, in such an apparatus, the conveying distance of the recording material is long and the output speed cannot be improved, and the recording material is heated and pressed twice in order to fix the toner image. In the print on the opposite side, transfer defects such as wrinkles and curls in the image due to paper wrinkles are likely to occur, and there has been a problem of deterioration in image quality.

In order to solve the problem of the double-sided image forming apparatus, an image is transferred to both sides of a recording material in an unfixed state, and thereafter, fixing is performed only once. Techniques have been proposed for preventing transfer defects on the opposite surface. For example, a technique described in JP-A-7-72682 will be described with reference to FIG. 42. First, the first surface of the recording material 207 supplied from the recording material After the image developed by the developing unit 202 is transferred on the first transfer unit 203, the recording material 207 is wound and held by the counterclockwise rotation 211 of the transfer holding body 210 having the suction hole. Next, the image to be transferred to the second surface is developed on the photoreceptor belt 201, and the recording material 207 is transferred by the second transfer unit 204 in synchronization with the clockwise rotation 212 of the transfer holder 210.
The image is transferred to the second surface of the recording material 207, and the recording material 207 is conveyed to the fixing device 206 in a state of being floated by the air conveyance device 205, so that both surfaces of the recording material 207 can be simultaneously fixed.

[0005]

However, Japanese Patent Laid-Open No.
In Japanese Patent Application Laid-Open No. 72682/1990, both sides of the image can be fixed at the same time. However, since the recording material after transferring both sides is conveyed by the air conveyance device 205 using the air conveyance method, the recording material 207 to the fixing device 206 is fixed. It is difficult to control the entry position of the recording material 2
07, the unfixed transferred image portion comes into contact with the surrounding members, causing image disturbance.
However, there is a problem that paper wrinkles occur at the time of fixing due to the poor posture of entering the camera.

Here, as means for guiding the unfixed recording material to the fixing device, a so-called gripper disclosed in Japanese Utility Model Laid-Open No. 57-100748 is adopted, and the recording material is conveyed to the fixing device with the leading end thereof being added. Although it is possible to transfer the image to the portion of the recording material held by the gripper, the problem that the image area is narrowed cannot be solved.

A method is also conceivable in which an unfixed recording material is guided to a fixing device by using a star wheel made of a thin sheet conveying member having a sharpened tip. In this method, although there is no area where an image cannot be transferred, Problems such as disturbance of an image occurring at a portion contacted by the star wheel and a broken line appearing, and toner remaining on the star wheel adhering to a recording material remain.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned technical problems. In guiding a recording material transferred by a transfer unit to a fixing device, the present invention does not reduce an image carrying area, and An object of the present invention is to provide a recording material transporting device capable of reliably guiding a recording material to a fixing unit without causing image disturbance, and an image forming apparatus using the same.

[0009]

That is, according to the present invention, as shown in FIG. 1, a transfer means 2 for transferring an unfixed image to a recording material 4 and fixing the unfixed image transferred to the recording material 4 are provided. A recording material transporting device disposed between the fixing device 3 and the recording material 4 for guiding the recording material 4 from the transfer device 2 to the fixing device 3,
A guide member 1 is provided, in which only the edge of the recording material 4 abuts, and the leading end position of the recording material 4 is guided to a proper entry position into the fixing means 3.

In such technical means, the recording material transporting device is applied to an image forming apparatus having a transfer means 2 and a fixing means 3, and a recording material 4 from the transfer means 2 to the fixing means 3. The transfer route is applicable to any of vertical, horizontal, oblique straight lines and curved routes. Further, the transfer unit 2 and the fixing unit 3 are not necessarily limited to the double-sided transfer and the double-sided fixing. The transfer unit 2 and the fixing unit 3 function effectively even when the transfer and the fixing are performed only on one side of the recording material 4. When an image is transferred and fixed to both sides, the technical effects of the present invention can be more effectively enjoyed.

The guide member 1 includes a recording material 4.
That is, it is necessary that only the edge of the recording material 4 abuts without contacting the surface of the recording material 4 and that the leading end position of the recording material 4 is guided to a proper entry position into the fixing unit 3. Here, the “edge of the recording material 4” is not limited to the front end of the recording material 4, but includes an edge (side end or the like) other than the front end of the recording material. In this case, only the leading end or the side end of the recording material 4 may be brought into contact, or both ends of the leading end and the side end of the recording material 4 may be brought into contact. Further, “fixing means 3
The "appropriate entry position to the recording medium"
Means that the leading end of the recording material has reached the vicinity of the nip of the fixing means 3, for example.

As a preferable structure of the guide member 1, it is preferable that the guideability of the recording material 4 be kept good, and the upstream side in the conveying direction of the recording material 4 is wider than the downstream side and narrows toward the downstream side. Is preferred. As a specific configuration example at this time, a pair of partition members may be arranged to face each other, or an appropriate selection may be made, such as opening an opening serving as a passage in a member having a V-shaped cross section.

Further, in a mode in which the span between the transfer means 2 and the fixing means 3 is long to some extent, in order to keep the guideability of the recording material 4 good, as the guide member 1, from the transfer means 2 to the fixing means 3 It is preferable that the recording material 4 be moved to guide the recording material 4 to a proper entry position of the fixing unit 3. In this case, the guide member 1 may be moved in such a manner that the position of the entire guide member 1 moves, or in which only the guide surface moves (for example, a moving body such as a rotating belt forming the guide surface moves). Including both. Further, in the movable type guide member 1, from the viewpoint of effectively preventing the interference between the guide member 1 and the recording material 4, the speed of the guide member 1 in the transport direction of the recording material 4 is the same as that of the recording material. It is preferable that the transfer speed is set equal to or faster than the transfer speed of No. 4.

Further, in the embodiment of the guide member 1 (both fixed type and movable type) for supporting the side edge of the recording material 4 in contact with the recording material 4, the recording material 4 is required to correspond to the recording material 4 of various sizes. It is preferable that the recording material 4 is designed to be variable in the width direction orthogonal to the transport direction, and to support and support the side edge of the recording material 4. Further, from the viewpoint of keeping the jam clearability of the recording material 4 good, the guide member 1 (fixed type,
It is preferable that the movable type can be manually moved.

In a mode in which the span between the transfer means 2 and the fixing means 3 is long to some extent, the rear end of the recording material 4 which has passed through the transfer means 2 falls down, and a peripheral member is placed near the conveyance path of the recording material 4. In such a case, there is a concern that the rear end of the recording material 4 may come into contact with peripheral members. From the viewpoint of effectively avoiding such a situation, the recording material 4
It is preferable to add a trailing end guide member that contacts the trailing edge of the recording material 4 and moves with the movement of the recording material 4 to prevent the trailing edge of the recording material 4 from falling down. In this case, the rear end guide member may be provided separately from the guide member 1, but the function of the rear end guide member may be added to the guide member 1.

Further, various functional members or functional parts may be added to the guide member 1. For example, in order to more effectively prevent the image disturbance of the recording material 4, the guide member 1 may be provided with a heat source of a hypothetical wearing, or a situation in which the dirt attached to the guide member 1 is reversely transferred to the recording material 4. The guide member 1 may be provided with a cleaner in order to avoid the problem effectively, or the guide member 1 may also be used as a heat shield cover to shut off the heat from the fixing means 3.

From the viewpoint of further stabilizing the conveying posture of the recording material 4, in addition to the guide member 1, between the transfer means 2 and the fixing means 3, the recording material 4 is conveyed by airflow to the recording material 4. An airflow control means for controlling the attitude may be further provided.

Further, preferred embodiments of the recording material conveying apparatus include the following. That is, as shown in FIGS. 2A and 2B, the present invention relates to a transfer unit 2 for transferring an unfixed image to a recording material 4 and a fixing unit 3 for fixing the unfixed image transferred to the recording material 4. And a recording material transport device for transferring the recording material from the transfer means 2 to the fixing means 3, wherein the recording material is disposed at a predetermined set position, and only the edge of the recording material 4 is in contact with the recording material. 4 is the fixing means 3
Guide member 1 guided to the proper entry position 7
And a retracting unit 5 for retracting the guide member 1 at the set position to the retracted position when the leading end position of the recording material 4 is guided to the appropriate rush position 7 to the fixing unit 3. is there. Here, the “set position” means a position where the guide member 1 is set to exhibit the guiding function, and is fixedly determined if the guide member 1 is a fixed type. If it is a movement type, it moves appropriately. In addition, the evacuation unit 5 is preferable in that the interference between the guide member 1 and the recording material 4 can be effectively suppressed when the guide function of the guide member 1 ends.

In the embodiment having the retracting means 5, the rear end position of the recording material 4 waits for the next recording material 4 in the guide member 1, as shown in FIG. 2C. Return means 6 for returning the guide member 1 to the standby position 8 under the condition of reaching a position which does not interfere with the standby position 8
It is preferable to further include This return is performed by the recording material 4
The rear end position is performed under the condition that the rear end position of the guide member 1 does not interfere with the standby position 8, and is preferable from the viewpoint of preparing the conveyance of the next recording material 4 without damaging the recording material 4.
Note that the standby position 8 may be provided separately from the set position, or may be the same as the set position.

Further, the present invention is not limited to a recording material conveying apparatus, but also applies to an image forming apparatus. In this case, as shown in FIG. 1 or FIG. 2, the image forming apparatus according to the present invention includes a transfer unit 2 for transferring an unfixed image to a recording material 4 and a fixing unit for fixing the unfixed image transferred to the recording material 4. And a recording material transporting device (including the guide member 1) to which the present invention is applied, which is disposed between the transfer unit 2 and the fixing unit 3.

In a recording material transporting apparatus using a movable type guide member 1 as shown in FIG. 2, for example, a recording material 4 carrying an unfixed image from the transfer means 2 to the fixing means 3 is provided. When the recording material 4 is guided, an edge position, for example, a leading end position of the recording material 4 is brought into contact with the guide member 1, and the guide member 1 is moved in accordance with the movement of the leading end position accompanying the conveyance of the recording material 4. In other words, it can be said that a new recording material conveying method is implemented in which the recording material 4 is guided to the fixing unit 3 without bringing the surface of the recording material 4 other than the front end position into contact.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the accompanying drawings. First Embodiment FIG. 3 is an explanatory view showing a first embodiment of a two-sided image forming apparatus incorporating a recording material conveying apparatus to which the present invention is applied.
In FIG. 1, the two-sided image recording apparatus is a full-color (in this embodiment, yellow (Y), magenta (M),
The first image forming unit 120a forms a cyan (C), black (K)) image and forms a first image on the front side Pa of the paper P, and forms a second image on the back side Pb of the paper P. The second image forming unit 120b and both image forming units 120
a, a two-sided image fixing device 100 for fixing an unfixed image on a sheet P as a recording material that has passed through the recording material, and a sheet for conveying the sheet P between the two image forming units 120 a, 120 b and the two-sided image fixing device 100. Transport device (recording material transport device)
162 (specifically, a paper tip guide 162a,
162b).

In the present embodiment, each image forming unit 12
Reference numerals 0a and 120b denote first photosensitive drum groups 121a (specifically, 121aY and 121aY) for forming YMCK toner images, respectively.
121aM, 121aC, 121aK), the second photosensitive drum group 121b (specifically, 121bY, 121b)
M, 121bC, 121bK), intermediate transfer belts 125a, 125b arranged in contact with the first and second photoconductor drum groups 121a, 121b, and toner on the first and second photoconductor drum groups 121a, 121b. The images T1 and T2 (for example, a normal image in the present embodiment) are transferred to the intermediate transfer belt 125.
a, primary transfer rolls 126a for primary transfer to 125b,
126b (specifically, 126aY, 126aM, 126
aC, 126aK, 126bY, 126bM, 126b
C, 126 bbK) and the intermediate transfer belts 125 a, 125
A secondary transfer device 140 (in this embodiment, a common device for the first and second image forming units 120a and 120b) for collectively transferring the toner images T1 and T2 on the both sides of the sheet P, an intermediate transfer belt 125a, And belt cleaners 150a and 150b for cleaning the residual toner on the surface 125b.

The polarity reversing corotron 128 and a grounded opposing roll (in the present embodiment, a holding roll for the intermediate transfer belt 125b described later) are located downstream of the primary transfer position of the intermediate transfer belt 125b of the second image forming section 120b. 133 is disposed to face the intermediate transfer belt 125b. Around the first and second photoreceptor drum groups 121a and 121b, respective electrophotographic devices (not shown) for charging, exposing, developing, and cleaning are arranged.

In this embodiment, each of the intermediate transfer belts 125a and 125b is provided with an appropriate number of holding rolls (1).
One is a driving roll and the other is a driven roll), and the first and second photosensitive drum groups 121a and 121
It rotates in synchronization with b. The intermediate transfer belts 125a and 125b are made of polyimide, acrylic, vinyl chloride, polyester, polycarbonate,
A resin such as polyethylene terephthalate (PET) or various rubbers is formed to contain an appropriate amount of an antistatic agent such as carbon black so that the volume resistivity is 10 ⁹ to 10 ¹⁴ Ω · cm. It is set to 0.08 mm.

Further, in the present embodiment, the secondary transfer device 1
Reference numeral 40 designates holding rolls arranged corresponding to areas where the respective intermediate transfer belts 125a and 125b are in contact with or close to each other as secondary transfer rolls 140a and 140b.
Contact roll 1 that contacts secondary transfer roll 140a
A transfer bias 141 is applied to the secondary transfer roll 140a via the contact roll 148, and the secondary transfer roll 140b is grounded. Here, the secondary transfer rolls 140a, 140b
Can be transferred using both conductive materials. However, in the case of transferring to a small-sized paper, when the first and second intermediate transfer belts 125a and 125b come into direct contact, the secondary transfer rolls 140a and 140b are used. Since an excessive current flows between them, a sufficient transfer electric field cannot be formed and transfer failure occurs, and the intermediate transfer belts 125a and 125b are easily damaged. It is preferable to use one coated with a conductive or insulating material.

In the present embodiment, for example, the secondary transfer roll 140a has a metal shaft coated with an insulating EPDM rubber, the surface of which is coated with a thin layer of a conductive EPDM rubber, and has a surface resistance of 10 ^9. Ω / cm ² was used. A metal shaft was used for the contact roll 148. Further, the secondary transfer roll 140b is coated with a metal shaft coated with EPDM rubber in which carbon black is dispersed, and has a surface resistance of 10 ⁵ Ω / cm ^2.
Was used.

Further, in this embodiment, the toner images T1 and T2 use negatively charged toner,
YM for 6aY to 126aK, 126bY to 126bK
DC current +10 μA for each transfer of CK, +300 μA for polarity reversal corotron 128, grid voltage 500
A DC voltage of -2 kV was applied to a contact roll 148 in contact with the secondary transfer roll 140a.

In this embodiment, a double-sided image fixing device (hereinafter, simply referred to as a fixing device if necessary) 100
The heating roll 101 mainly heats the toner image T1 on the front side Pa of the paper P, and the heating roll 102 mainly heats the toner image T2 on the rear side Pb of the paper P. Here, the heating roll 101 and the heating roll 1
Numeral 02 has heaters 103 and 104 built in the center, respectively, and is arranged so as to have a predetermined nip area N under pressure. In the present embodiment, as the heating roll 101 and the heating roll 102, for example, one in which a heat-resistant rubber layer is formed on the surface of a metal tube such as SUS is used.
The heaters 103 and 104 are, for example, 600 W
The heating roll 101 and the heating roll 1
02 is heated to about 160 ° C. An oil supply device (not shown) for maintaining toner releasability is provided upstream of the nip area N between the heating rolls 101 and 102, and a heating roll is provided downstream of the contact nip area N. Cleaning device (not shown) for removing residual toner and the like on heating roll 101 and heating roll 102
Are arranged in contact.

In the present embodiment, a sheet conveying device for conveying a sheet between the image forming units 120 a and 120 b and the fixing device 100 is a pair of sheet leading guides 162.
a, 162b. This paper leading edge guide 162
a and 162b guide the sheet P sent to the subsequent stage of the secondary transfer device 140 near the entrance side of the nip area N of the fixing device 100, and the secondary transfer device 140 side is the fixing device 1
Opposite to each other in a substantially V-shape so as to define a passage narrowing toward the fixing device 100 side wider than 00. Here, the size of the paper leading edge guides 162a and 162b only needs to correspond to the range in which the leading edge of the curled paper P abuts, and the layout of the paper leading edge guides 162a and 162b is determined when the leading edge of the paper P abuts. It is sufficient that the sheet is inclined to the extent that the sheet is guided and conveyed to the nip area N of the fixing device 100. Further, in the present embodiment, the paper leading edge guides 162a,
2b is made of, for example, a heat-resistant reinforced plastic surface coated with a low-friction Teflon coat.

Next, an image forming process of the double-sided image forming apparatus according to the present embodiment will be described. First photosensitive drum group 121aY, 121aM, 121aC, 121aK
From the primary transfer rolls 126aY, 126aM, 126a
The first toner image T1 is continuously transferred onto the first intermediate transfer belt 125a in the order of YMCK by C and 126aK. On the other hand, the second photosensitive drum groups 121bY and 121bY
The second toner image T2 (YMCK) formed on bM, 121bC, 121bK is transferred to the primary transfer roll 126bY,
After the images are sequentially transferred onto the second intermediate transfer belt 125b by 126bM, 126bC, and 126bK, a voltage is applied to the polarity reversal corotron 128 so that the second toner image T
2 is inverted.

Then, the sheet P is conveyed at an appropriate timing, and the intermediate transfer belt 125a,
After the toner images T1 and T2 on the sheet 125b are simultaneously transferred onto the sheet P, the sheet P is
To the toner images T1, T on the sheet P by the fixing device 100.
Fix 2

Here, the principle of operation of the sheet conveying device will be described. The paper leading edge guides 162a and 162b are installed at the subsequent stage of the secondary transfer device 140, and have a passage that is largely opened on the secondary transfer device 140 side. For this reason, even if the paper P after the transfer process is greatly shaken due to electrostatic force, curl, or the like, the leading end of the paper P contacts one of the paper leading edge guides 162a or 162b. Then, the sheet leading edge guide 162a or 162b guides and conveys the sheet P, the tip of which abuts against, along the guide surface that narrows toward the fixing device 100 side.
a, 162b, the sheet P is passed through a narrow exit passage (a passage slightly wider than the thickness of the sheet P in consideration of the thickness of the toner image) in the nip area N of the fixing apparatus 100. Guide near the entrance. Therefore, as shown in FIG. 3, even if the sheet P is conveyed out of the nip area N of the fixing device 100, the sheet leading edge guides 162a and 162
4B, the leading end position of the sheet P is forcibly moved to the vicinity of the entrance of the nip area N of the fixing device 100 as shown in FIGS. The toner images T1 and T2 guided to the nip area N and on the sheet P
Is firmly established.

Second Embodiment FIG. 5A shows a second embodiment of a recording material conveying apparatus to which the present invention is applied. The sheet conveying device as the recording material conveying device according to the present embodiment includes sheet leading end guides 180a, 180
A belt type guide is installed as b. The paper leading edge guides 180a and 180b are respectively provided with driving rolls 181a and 181b and driven rolls 182a and 182.
b, and the rotating belt 1 wrapped around these rolls
83a and 183b, and the fixing device 10
They are arranged in a substantially V-shape so that the passage narrows toward the zero side. Note that components similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and a detailed description thereof will be omitted.

In this embodiment, when the leading edge of the sheet P is detected by a sensor (not shown), the driving roll 18
1a and 181b rotate, and the rotating belts 183a and 183
b starts to rotate. When the leading end of the sheet P passing through the secondary transfer device 140 touches from a predetermined position, the sheet P
Abuts against the rotating belt 183a or 183b, is guided to the vicinity of the entrance of the nip area N of the fixing device 100 with the movement of the rotating belt 183a or 183b, and the guided sheet P is moved to the nip area N of the fixing device 100. And rush into it.

In particular, in the present embodiment, the rotating belt 18
The peripheral speeds 3a and 183b in the paper transport direction are set to be equal to or faster than the transport speed of the paper P. With this configuration, for example, the sheet leading edge guides 180a, 180
Even if there is a deposit such as dust on b, it is possible to prevent the paper P from colliding with the dust and failing to enter the fixing device 100. That is, a more reliable paper transport device can be realized.

FIG. 5B shows a modification of the recording material conveying apparatus according to the second embodiment. In the figure, a paper transporting device as a recording material transporting device according to the present modification is substantially the same as that of the second embodiment. A plurality of ridges extending in the width direction at predetermined intervals are used. With this configuration, for example, even when the paper P having a large curl is conveyed, the presence of the ridges causes the rotation belts 184a and 184a to rotate.
Since the transportability of the 84b to the leading end of the sheet P is enhanced, the sheet P can be more reliably transported to the fixing device 100. Therefore, according to the present modification, a device with higher reliability than in the second embodiment can be realized.

Third Embodiment FIG. 6 shows a third embodiment of a recording material conveying apparatus to which the present invention is applied. In the figure, a sheet conveying device as a recording material conveying device according to the present embodiment includes a sheet leading end guide 185.
As a and 185b, a pair of guide bodies 851 that are inclined and arranged in a substantially V shape are provided with a heating element 852 such as a heater, and a guide chute 853 made of a parallel plate is provided on the fixing body 100 side of the guide body 851. Is used. Elements similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof will be omitted. The same applies to the following embodiments and modifications. With such a configuration, a toner image on the sheet P can be tentatively attached before the fixing device 100 enters. By temporarily attaching the toner image on the sheet P, even if the image surface of the sheet P touches a peripheral member, the sheet P can be made to enter the fixing device 100 without disturbing the image surface.

Fourth Embodiment FIG. 7A shows a fourth embodiment of a recording material conveying apparatus to which the present invention is applied. In FIG. 1, a sheet transporting device as a recording material transporting device according to the present embodiment includes first to third embodiments.
Unlike this, the paper side end guide 186 is configured to guide both side edges of the paper P. Specifically, the paper-side end guide 186 (specifically, 186a, 18
6b), as shown in FIG. 7 (b), is configured by arranging channel materials having a V-shaped cross section so as to face each other. , Paper side end guides 186a, 186b
Is configured to be variable. With such a configuration, it is possible to cope with any paper width. Therefore, according to the present embodiment, the posture of the leading edge of the sheet P can be stabilized by restraining the side edges of the sheet P from both sides by the pair of sheet side end guides 186a and 186b. Moreover, since the side edges of the sheet P are guided, there is no possibility that the sheet side guides 186a and 186b come into contact with the image surface of the sheet, and a highly reliable apparatus can be obtained.

FIGS. 8 and 9 show modifications of the fourth embodiment. FIG. 8A shows a configuration in which the paper-side end guide 187 is curved. With such a configuration, the paper P is transported while being curved, and as a result, the paper P is transported with its stiffness increased. Therefore, as compared with the fourth embodiment, it is possible to further stabilize the posture of the leading end of the sheet P, and to realize a more reliable apparatus. FIG. 8B is a diagram in which a sheet leading end guide 188 for guiding the leading end of the sheet is provided at the entrance of the sheet side end guide 187. With such a configuration, the paper P can be reliably inserted into the paper side end guide 187.
Can be rushed, so that a more reliable device can be realized as compared with FIG.

FIG. 9A shows a sheet-side end guide 186.
Is applied when the transport direction of the paper P is the horizontal direction. Even with such a configuration, it is possible to stabilize the leading edge of the sheet P by blowing air from the fan 189 provided below the sheet-side end guide 186, and to convey the sheet P to the subsequent fixing device 100. . Furthermore, FIG. 9 (b)
FIG. 8B shows an example in which the paper-side end guide 187 and the paper front-end guide 188 shown in FIG. 8B are applied when the transport direction of the paper P is horizontal. With such a configuration, the paper P can be transported using the waist of the paper P, so that the fan and the like required in the modification of FIG. Further, since the paper side end guide 187 is provided with the paper front end guide 188 at the entrance, it is possible to reliably guide the paper P to the paper side end guide 187 similarly to the modified embodiment of FIG. 8B. And a fixing device 10 at a later stage.
It is possible to reliably transport the paper P to the nip area 0.

Fifth Embodiment FIG. 10 shows a fifth embodiment of the transport apparatus to which the present invention is applied. In the figure, a sheet conveying device as a recording material conveying device according to the present embodiment includes a sheet leading end guide 163 (specifically, 163a, 163b) in front of the fixing device 100.
And the secondary transfer device 140 and the paper leading end guide 16
3, a fan 170 and a sensor 171 are opposed to each other with a reference sheet conveyance path interposed therebetween. With such a configuration, it is possible to reduce the passage area of the sheet leading end guide 163 opened on the side of the secondary transfer device 140, and it is possible to reduce the size of the sheet conveying device.

Next, the operation of the paper conveying apparatus according to the present embodiment will be described. Now, the sheet P that has passed through the secondary transfer device 140 is conveyed by a curl or an electrostatic force while being displaced from a line connecting the secondary transfer nip area and the fixing nip area as shown in FIG. . This change position is detected by the sensor 171, and the fan 170 is driven so that the wind speed according to the output result of the sensor 171 is applied to the paper P.
The position control range of the sheet P by the fan 170 is as shown in FIG.
As shown in FIG. 0 (b), it is sufficient that the position is within a passage range opened to the secondary transfer device 140 side of the sheet leading end guide 163, and strict position control is not required. Therefore, a very simple control system is sufficient. Here, the sheet positioned in the entrance side passage of the sheet leading end guide 163 is shown in FIGS. 10B to 10D.
As shown in FIG. 6, the leading end of the fixing device 100 is guided to the nip area of the fixing device
Thus, the toner images T1 and T2 on the sheet P are fixed.

Here, the fan 170 is driven for controlling the position of the sheet P, but is driven even when the sheet P is not present between the secondary transfer device 140 and the fixing device 100. Is also good. By driving the fan 170 when there is no paper P, the fixing device 10
The influence of heat from 0 can be eliminated, and, for example, it is possible to prevent the residual toner and the like on the intermediate transfer belts 125a and 125b from sticking to the intermediate transfer belts 125a and 125b and preventing the transfer performance from being adversely affected. It becomes possible. Therefore, it is possible to realize a more reliable image forming apparatus without increasing the cost.

FIG. 11 shows a modification of the fifth embodiment, in which the fifth embodiment is applied when the paper P is conveyed in the horizontal direction. 4 shows a process of conveying a sheet P. In the case of such a configuration, the sheet leading edge guide 163 does not need to be a pair, and may be provided on only one side. Therefore, it is clear that the paper transport device can be further downsized, and the transport performance of the paper is not impaired at all. Note that the location where the fan 170 is provided is preferably below the transport path of the paper P.

Sixth Embodiment FIG. 12A shows a sixth embodiment of a recording material conveying apparatus to which the present invention is applied. In the figure, a sheet transporting device as a recording material transporting device according to the present embodiment is the same as that of the fifth embodiment.
(Similar components are denoted by the same reference numerals as in the first embodiment), but different from the fifth embodiment, the cover portions 105a and 105b of the fixing device 100 are added to the paper leading edge guides 106a and 106b. Things. With such a configuration, the secondary transfer device 140 is less likely to be affected by heat generated from the fixing device 100, and
The air flow from the fan 170 is applied to the fixing roll (heating roll,
Since there is no direct contact with the pressure rolls 101 and 102, the temperature of the surface of the fixing rolls 101 and 102 does not partially decrease, and the surface temperature of the fixing rolls 101 and 102 can be kept constant. Become.

Accordingly, a more reliable double-sided image forming apparatus can be realized without impairing the fixing performance of the fixing device 100. In addition, the above-mentioned paper tip guide 1
As a material of 06a and 106b, a material obtained by applying a low-friction Teflon coat to the surface of a heat-resistant reinforced plastic is desirable. FIG. 12B is a modification of the sixth embodiment, and shows a configuration example in the case where the sheet conveyance direction is horizontal. Even in the case of such a configuration, it is possible to realize a highly reliable double-sided image forming apparatus as in the sixth embodiment without impairing the sheet conveyance performance.

Seventh Embodiment FIG. 13 is a schematic configuration diagram showing a seventh embodiment of a double-sided image forming apparatus to which the present invention is applied. The image forming apparatus in this figure is a double-sided image forming apparatus that forms a full-color image of yellow (Y), magenta (M), cyan (C), and black (K).
Image forming unit 120 that forms a first image on the front side Pa of
a, a second image forming unit 120b for forming a second image on the back side Pb of the sheet P, and these image forming units 120 (120
a, 120b), a double-sided image fixing device 100 for fixing an unfixed image formed between the image forming units 120 and a sheet P as a recording material between each image forming unit 120 and the double-sided image fixing device 100.
And a paper transport device (recording material transport device) 30 for transport. Here, components similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed description thereof will be omitted.

In this embodiment, each image forming unit 12
0 (120a, 120b) and the fixing device 100, the sheet conveying device 30 is provided with a secondary transfer device 140
Edge guides (corresponding to sheet edge guides) 31a and 31 which are arranged at the subsequent stage and guide the edge of the sheet P
b. These paper end guides 31a and 31b
Has an opening on each image forming unit 120 side (upstream side of sheet conveyance), and is arranged so that the fixing device 100 side (downstream side of sheet conveyance) is in contact. The contact portion is disposed so as to be substantially located on a straight line connecting the nip area of the secondary transfer device 140 and the nip area of the fixing device 100. Further, in the present embodiment, the paper end guides 31a and 31b are formed by applying a low friction Teflon coat to a metal surface such as SUS.

The paper transporting device 30 has a guide moving mechanism for moving the paper end guides 31a and 31b to predetermined positions. The guide moving mechanism will be described in detail later, but the standby position (initial position), which is a position in the paper transport direction (Y direction in the figure), and the vicinity of the nip area of the fixing device 100 (appropriate paper entry position), The paper end guides 31a and 31b are moved to a set position and a retreat position, which are positions in a direction (X direction in the figure) substantially orthogonal to the paper transport direction, and to the standby position (initial position) described above. The movement of the sheet transport device is controlled by the control unit 32.

Next, the operation of the sheet conveying device 30 controlled by the control unit 32 will be described with reference to the operation explanatory diagram of FIG. 14 and the flowchart of FIG. Paper edge guide 31a
And 31b are downstream (initial positions) of the secondary transfer device 140
Waiting for the paper P to be transported (S10).
1). Here, when it is detected by the discharge signal that the paper P is discharged from the paper tray (not shown) (S102), a timer (not shown) is activated (S103), and after a predetermined time has passed, the end of the paper P is moved to the paper end. Section guide 31a or 31
At the time when it is considered to substantially abut on the sheet end guides 31a and 31b, as shown in FIG.
Movement is started in the direction of Xa (S104). At this time, the moving speeds of the paper end guides 31a and 31b are substantially equal to the paper conveyance speed, and the leading end position of the paper P reaches the inner contact portion of the paper end guides 31a and 31b or its vicinity. .

Next, when the sheet edge guides 31a and 31b reach the vicinity of the nip area of the fixing device 100, FIG.
As shown in (b), the paper edge guides 31a and 31b
Move in the directions of arrows Ya and Yb, respectively, and retreat to a predetermined retreat position until the sheet P passes (S105). At this time, the sheet P is released from the sheet end guides 31a and 31b, and enters the double-sided image fixing device 20 while maintaining its attitude substantially, so that the unfixed toner images held on both sides of the sheet P are fixed. Is done. On the other hand, the paper edge guide 31a
And 31b are positions where the sheet P does not come into contact with the sheet end guides 31a and 31b within the operation range of the sheet end guide when the sheet P is conveyed, and the sheet end guide 31a reaches this position. When the timer reaches 31 and 31b, the timer is activated (S106), and after a lapse of a predetermined time, that is, a time during which the paper P does not contact the paper edge guides 31a and 31b, in other words, after the paper P In consideration of the time when the edge passes the predetermined position, the paper edge guides 31a and 31b move to the standby position (S107),
It is configured to return to the initial position.

The position of the sheet P may be detected by the sensor 29 to control the operation of the sheet end guides 31a and 31b. Such an operation is shown in the flowchart of FIG. That is, the paper edge guides 31a and 31b
Waits for the paper P to be conveyed at the standby position (initial position) (S111), and when the sensor 29 detects the leading edge of the paper (S112), a timer (not shown) is activated (S11).
3) When a predetermined time has elapsed and the end of the sheet P is considered to be almost in contact with the sheet end guide 31a or 31b, the sheet end guides 31a and 31b are moved to the state shown in FIG.
As shown in FIG. 4A, movement starts in the direction of arrow Xa (S114). Next, the sheet edge guides 31a and 31a
When 1b reaches the vicinity of the nip area of the fixing device 20, FIG.
As shown in (b), the paper end guides 31a and 31b move in the directions of arrows Ya and Yb, respectively, and retreat to a predetermined retreat position shown in FIG. 14C (S115). At that time, paper P
Enters the fixing device 100, the unfixed toner images are sequentially fixed, and when the sensor 29 detects the rear end of the sheet P (S1).
16), the timer is activated (S117), and after a lapse of a predetermined time, that is, the sheet P is moved to the sheet end guides 31a and 31b.
After a lapse of time during which the sheet edge guides 31a and 31b do not come into contact with each other, the sheet end guides 31a and 31b start moving in the Za and Zb directions shown in FIG.
8) Control is performed to return to the initial position.

FIGS. 17 to 20 are explanatory views illustrating an example of a guide moving mechanism for moving the sheet end guides 31a and 31b in the sheet conveying device 30. FIG.
The paper end guides 31a and 31b have ball bearings 33a.
And 33b, and these ball bearings are fitted in triangular grooves 35a and 35b formed in the base member 34 of the sheet conveying device. Also, the paper edge guide 31a
And 31b are paper end guide holders 36a and 36b
The arrows Ya and
Guided in the direction of Yb, and arrows Ya and Yb, respectively.
Are applied by the springs 37a and 37b. The paper edge guide holders 36a and 36b are provided with the secondary transfer device 1 for the paper edge guides 31a and 31b.
Stoppers 38a and 38b for pressing the side close to 40 are provided, and a rotational force by a spring (not shown) acts on the stoppers 38a and 38b in the directions of arrows La and Lb with Oa and Ob as the rotation centers, respectively. . Further, stopper release members 39a and 39b are provided, and are configured to press the stoppers 38a and 38b when the paper end guide holders 36a and 36b move.

In the paper transport device 30 having the above-described configuration, the paper edge guide holders 36a and 36b move the paper edge position from the paper standby position shown in FIG. Section guide 31a or 3
Recognizing that it has substantially contacted 1b, 36a and 36b start moving together in the direction of arrow Xa. The moving speed at this time is set to be substantially the same as or slightly higher than the transport speed of the paper P. The movement of the paper end guide holders 36a and 36b causes the ball bearings 33a and 33b to move into triangular grooves 35.
a and 35b move along one side and the paper edge guide 31
a and 31b move similarly. And the ball bearing 33
a and 33b are formed at the lower ends of triangular grooves 35a and 35b formed in the base member 34, that is, the fixing device 10
When it reaches the vicinity of the nip area of zero, the stoppers 38a and 38b are moved to the stopper release members 39a as shown in FIG.
And 39b to push the paper end guides 31a and 31b in the directions of arrows Ka and Kb. At this time,
The paper end guides 31a and 31b are guided in the directions of arrows Ya and Yb, respectively, and move to the positions shown in FIG. 19 because the pulling forces by the springs 37a and 37b are acting in the same direction.

Next, after the sheet P has passed a predetermined position,
The paper end guide holders 36a and 36b are shown in FIG.
Move in Xb direction. At this time, since the ball bearings 33a and 33b are fitted in the triangular grooves 35a and 35b, the paper end guides 31a and 31b are respectively inclined obliquely upward along the grooves, that is, in the directions of Za and Zb. Moving. When the paper end guide holders 36a and 36b move to predetermined positions, the stoppers 38a and 38b
Is the secondary transfer device 14 for the sheet edge guides 31a and 31b.
0, and press the paper end guides 31a and 31b.
Returns to the sheet standby position shown in FIG. 17, that is, the initial position after the movement shown in FIG. 20, and completes the preparation for transporting the next sheet.

FIGS. 21 to 24 are explanatory views for explaining another example of the guide moving mechanism for moving the sheet end guides 31a and 31b in the sheet conveying device 30. FIG. The paper end guides 31a and 31b are provided with first ball bearings 40a and 40b and second ball bearings 41a and 41b. Here, the second ball bearings 41a and 41
“b” is fitted in a concave groove (a groove bent at an acute angle) 43a and 43b of the bearing guide 42, and the first ball bearings 40a and 40b are concave grooves 43a and 43b. Are further fitted into triangular grooves 45a and 45b provided in the base member 44 through the holes. Further, the secondary transfer device 1 of the sheet edge guides 31a and 31b
The ends near the side 40 are given tensile forces in the directions obliquely above Ea and Eb by springs (not shown).
Further, guide plates 46a and 46b are provided on the base member 44, and the guide plates 46a and 46b are respectively rotated by arrows (not shown) around Qa and Qb by a spring (not shown).
a, a rotational force is given in the direction of Rb, and a triangular groove 45a
And 45b guide the first ball bearings 40a and 40b. In the standby state, the guide plates 46a and 46b guide the triangular grooves 45a and 45b in the vertical direction as shown in FIG.

In the paper transport device 30 configured as described above, the bearing guide 42 moves from the paper standby position shown in FIG. 21 to the paper end guide 31a or 31b, for example, when the signal of the sensor 29 is detected. Recognizes that it has almost contacted with, and starts moving in the direction of arrow Xa. The moving speed at this time is set to be almost the same as or slightly higher than the transport speed of the paper P. The movement of the bearing guide 42 causes the first ball bearings 40a and 40b to move into triangular grooves 45a and 45b.
Move along one side of the paper edge guides 31a and 31b.
Move as well. Then, the first ball bearings 40a and 4
0b is a triangular groove 45a formed in the base member 44.
And 45b, that is, near the nip portion of the fixing device 20, the ends of the sheet end guides 31a and 31b on the side close to the secondary transfer device 140 are inclined by springs in a direction obliquely above Ea and Eb. Due to being pulled, as shown in FIG. 22, the first ball bearings 40a and 40b move in the horizontal direction of Wa and Wb along the concave grooves 43a and 43b.
The second ball bearings 41a and 41b move obliquely upward from Wc and Wd. As a result, the paper end guides 31a and 31
b substantially rotates around the fixing device 100. By this substantially rotational movement, the sheet end guides 31a and 31b can be retracted to a position where the sheet P being transported is hard to contact.

After the above operation, the paper end guides 31a and 31b are retracted to the positions shown in FIG. 23 until the paper P passes in a direction substantially perpendicular to the transport direction Xa of the paper P. I have. After the sheet P has passed the predetermined position, the bearing guide 42 starts moving in the direction of the arrow Xb. At this time, as shown in FIG. 23, the first ball bearings 40a and 40a
b denotes the second ball bearings 41a and 41b in the directions of Fa and Fb.
Moves along the guide grooves in the directions of Fc and Fd, respectively. Thereafter, when the first ball bearings 40a and 40b reach the guide plates 46a and 46b, respectively, the first ball bearing 4
0a and 40b are guide plates 46a and 4b as shown in FIG.
6b is moved to reach the initial position in FIG. At this time, that is, when the paper end guides 31a and 31b and the bearing guide 42 reach the standby position, the guide plates 46a and 46b again return to a substantially vertical direction as shown in FIG. First ball bearing 40a
And 40b in the horizontal direction. With the above operation, the sheet edge guides 31a and 31b return to the initial positions, and the preparation for transporting the next sheet P is completed.

FIG. 25 illustrates the positional relationship of the elements constituting the guide moving mechanism described with reference to FIGS. 21 to 24 from one side. The paper end guide 31b has a first ball bearing 40b and a second ball bearing 41b,
The first ball bearing 40b fits into the triangular groove 45b of the base member 44 via the bearing guide. At that time, the guide plate 46b between the bearing guide 42 and the base member 44 regulates the operation direction with respect to the groove 45b.

FIG. 26 shows the sheet conveying device 30 according to the present embodiment, in which the above-described sheet end guide holder 36a is provided.
And 36b or an example of a mechanism for moving the bearing guide 42 in the Xa and Xb directions. Gear 5
1 is rotated by receiving a driving force from a driving source (not shown), and is converted into a linear motion by a pinion 52. The linear movement of the pinion 52 is transmitted by a lever 53 having a lever center 54, and the paper end guide holders 36a and 36b,
Alternatively, the bearing guide 42 is driven. Here, the paper end guide holders 36a and 36b or the bearing guide 42 is held in a linear motion by, for example, a known linear slide bearing 55, and the linear motion is controlled by controlling the driving of the gear 51. The speed is substantially the same as the paper transport speed. In the present embodiment, the drive is transmitted using the lever. However, there is no problem even if the pinion is provided directly on the paper end guide holder or the like.

In the above-described drive system, for example, if a handle 51a that can be manually operated is installed on the gear 51, if a jam occurs, the handle 51a is manually turned to The opening and closing operation of the sheet leading end guides 31a and 31b can be performed.
Therefore, the jammed paper can be easily taken out. Further, maintenance work of the guide moving mechanism can be easily performed.

Eighth Embodiment FIG. 27 shows an eighth embodiment of a recording material conveying apparatus to which the present invention is applied. In the present embodiment, the paper transporting device as a recording material transporting device has the leading edge contact portions of the paper edge guides (corresponding to the paper leading edge guide) 60a and 60b in advance near the nip area of the fixing device 20. It is made. Note that components similar to those of the seventh embodiment are denoted by the same reference numerals as those of the seventh embodiment, and a detailed description thereof will be omitted.

In this embodiment, the paper is
As shown in (a), after passing through the secondary transfer device 140, the tip thereof is detected by the sensor 29, and a timer (not shown) operates based on this signal. The opening timing of the sheet edge guides 60a and 60b is determined by this timer. In this state, the sheet edge guides 60a and 60b are at the set position shown in the drawing. On the other hand, as shown in FIG. 27B, the sheet P is moved to a proper entry position near the nip area of the fixing device 100 with only the end of the sheet P contacting the sheet edge guides 60a and 60b. The tip is transported. By the elapse determination of the predetermined time by the timer, the sheet edge guide 60 is determined.
When it is determined that the sheet P has reached the vicinity of the contact portions a and 60b, as shown in FIG.
a and 60b open in the directions of arrows Va and Vb, and the sheet P enters the fixing device 20 while maintaining its attitude substantially. At this time, the sheet end guides 60a and 60b are retracted to the retracted positions shown in FIG. Next, the rear end of the sheet P is
9, a timer (not shown) is activated based on this signal, and the timer determines the closing timing of the sheet edge guides 60a and 60b. When the sheet is inserted, as shown in FIG.
And 60b move in the directions of arrows Vc and Vd, again
As shown in (a), the system is ready to transport the next sheet.

In this embodiment, since the operation of the paper edge guides 60a and 60b is simple, the number of components can be reduced, and the size and cost of the apparatus can be reduced. In the present embodiment, it is preferable that the contact surfaces of the sheet end guides of the sheet end guides 60a and 60b be processed so that the leading end of the sheet is slippery from the viewpoint of preventing a paper jam. In the embodiment, it functions more effectively in a configuration in which the distance between the secondary transfer device 140 and the fixing device 100 is not so large.

In the seventh and eighth embodiments, for example, a comb shape as shown in FIG. 28 can be used for the paper end guides 60a and 60b (31a and 31b). When such a configuration is adopted, the leading ends of the paper end guides 60a and 60b (31a and 31b) do not come into contact with each other, so that unnecessary collision noise can be prevented and the component tolerance can be reduced. it can.
FIG. 28B is an explanatory plan view of FIG.

Ninth Embodiment FIG. 29 shows a ninth embodiment of a recording material conveying apparatus to which the present invention is applied. In the present embodiment, a paper transporting device as a recording material transporting device is substantially the same as that of the eighth embodiment, but employs belt-type paper edge guides (corresponding to paper edge guides) 61a and 61b. is there. The paper end guides 61a and 61b are composed of driving rolls 62a and 62b, driven rolls 63a and 63b, and rotating belts 64a and 64b, respectively. The same components as those in the second embodiment are described in the eighth embodiment.
The same reference numerals are used, and the detailed description is omitted here.

In this embodiment, as shown in FIG. 29, when the leading end of the sheet P is detected by the sensor 29,
The drive rolls 62a and 62b rotate, and the rotating belt 64
a and 64b start rotating in the directions of Ma and Mb. At this time, the peripheral speeds of the rotating belts 64a and 64b are set to be faster than the transport speed of the paper P. The fast setting ensures that the leading edge of the sheet enters the fixing device 20 while slightly sliding the leading edge of the sheet on the belt. Thereafter, when the leading edge of the sheet P reaches the vicinity of the fixing device 20, the sheet edge guides 61a and 61b are opened to a position where they do not come into contact with the sheet P, as in the eighth embodiment.
It should be noted that there is no problem if the rotation of the drive rolls 62a and 62b is started before the leading end of the paper P is detected by the sensor 29.

In the present embodiment, for example, even if foreign matter such as dust is present on the sheet edge guides 61a and 61b, the sheet P collides with the dust and the fixing device 1
Thus, there is no danger that the entry to 00 will fail, and a more reliable device can be realized.

For example, in the seventh to ninth embodiments, the case where the tip end of the sheet end guide is in contact has been described. However, as shown in FIG.
The end of (specifically, 65a and 65b) may have an open shape within a range h in which the thickness of the sheet P is larger than the thickness of the sheet P and the sheet P can enter the nip area of the fixing device 100 with good posture. By arranging the paper edge guide 65 in this way, the paper is not restrained by the paper edge guide 65, and the paper edge guide 65 is
Unnecessary force is not applied to the sheet when the sheet is retracted from the vicinity of the nip portion 0, and the sheet can be made to enter the nip area of the fixing device 100 while maintaining the posture of the sheet correctly.

FIG. 31 shows an image forming apparatus according to a tenth embodiment of the present invention. The present embodiment shows a mode in which the paper P is transported in the horizontal direction. When the sheet edge guide (corresponding to the sheet leading edge guide) 70 guides the leading edge of the sheet P, it moves in the direction of the arrow Sa at substantially the same speed as or slightly faster than the transport direction of the sheet P. Also, the secondary transfer device 14
A fan 71 as an airflow device for supplying wind power is provided between the fixing device 100 and the fixing device 100, and applies a wind force from below to the sheet P moving in the direction of the arrow Sa.
Note that components similar to those of the seventh embodiment are denoted by the same reference numerals as those of the seventh embodiment, and a detailed description thereof will be omitted.

FIGS. 32A and 32B are explanatory diagrams for explaining the operation of the sheet transport unit in the present embodiment. Since the present embodiment is configured as described above, the sensor 29 detects the leading end of the sheet P, and the sheet end guide 70 guides the sheet P based on the output result, and the speed is substantially the same as the sheet transport speed. When moving in the direction of the arrow Sa at the speed, the paper P
The sheet is conveyed to the fixing device 100 by the wind force from 1 while maintaining a substantially horizontal orientation. As shown in FIG. 32A, when the paper end guide 70 reaches the vicinity of the nip area of the fixing device 100, that is, when the leading end of the paper P reaches the vicinity of the nip area, the paper end guide 70 moves to the arrow Sb. And retracts from the vicinity of the nip area of the fixing device 100.

When the paper end guide 70 is retracted, the paper P enters the nip area of the fixing device 100 while keeping its attitude substantially. When the trailing end of the sheet P is detected by the sensor 29, a timer (not shown) is activated based on this signal, and the timer moves the sheet end guide 70 in the direction of arrow Sc as shown in FIG. It moves and returns to the initial position to prepare for transporting the next sheet P.

According to the present embodiment, as described above, even when the transport direction of the paper P is horizontal, a highly reliable paper transport function can be obtained as in the seventh to ninth embodiments. be able to.

Eleventh Embodiment FIGS. 33A, 33B and 33C show an eleventh embodiment of a recording material conveying apparatus to which the present invention is applied. The paper transporting device as the recording material transporting device according to the present embodiment is substantially the same as that of the tenth embodiment, but since the distance between the secondary transfer device 140 and the fixing device 100 is short, a fan as an airflow device is used. It is unnecessary. Note that Embodiment 10
The same components as those described in the first embodiment are denoted by the same reference numerals as in the tenth embodiment, and the detailed description thereof is omitted here.

In this embodiment, as shown in FIG. 33A, the sensor 29 detects the leading end of the sheet P, and based on the output result, the sheet edge guide 80 guides the sheet P to transport the sheet. When the paper P moves in the direction of the arrow Ja at substantially the same speed as the speed, the paper P is conveyed to the fixing device 100 while maintaining the horizontal orientation due to the waist of the paper. Next, FIG.
As shown in (b), the paper edge guide 80 is
0, that is, when the leading edge of the paper P reaches the proper entry position, the paper edge guide 80
Moves in the direction of arrow Jb in the figure, and retreats from the vicinity of the nip area of the fixing device 100. On the other hand, the sheet P enters the nip area of the fixing device 100 while substantially maintaining its leading end posture. When the trailing edge of the sheet P is detected by the sensor 29, a timer (not shown) is activated based on this signal, and the timer guides the sheet edge guide 80 in the direction of arrow Jc as shown in FIG. And returns to the standby position (initial position) to prepare for transporting the next sheet P.

With the above configuration, the fan as the airflow device provided in the tenth embodiment is not required, so that a highly reliable paper transport device can be provided. Thus, an inexpensive device can be provided.

Twelfth Embodiment FIGS. 34 and 35 show a twelfth embodiment of a recording material conveying apparatus to which the present invention is applied. In the present embodiment, a sheet conveying device as a recording material conveying device is configured such that the trailing end side of the sheet can be guided by the movable sheet front end guides 160a and 160b. By adopting such a configuration, the present invention can be applied to paper having a high water content and small stiffness.

Next, the operation of the sheet conveying device will be described. The paper leading edge guides 160a and 160b are waiting for the paper P to be conveyed at the subsequent stage (initial position) of the secondary transfer device 140. Here, when the paper P is discharged from a paper tray (not shown), a timer (not shown) is operated, and after a lapse of a predetermined time, the paper leading edge guides 160a, 160
0b operates in the direction of arrow Y, as shown in FIG. The paper guides 160a, 16 at this time
0b is substantially equal to the paper transport speed, and the paper P
Reaches the groove formed by the paper leading guides 160a and 160b or in the vicinity thereof. For example, when the paper transport speed is 160 mm / s, the leading end of the paper and the groove of the paper leading guides 160a and 160b Is desirably about 0 to 3 mm.

Further, the paper tip guides 160a, 160b
34 reaches the vicinity of the nip area of the fixing device 100, FIG.
(B) As shown in FIG. 35 (c) and FIG. 35 (a), after moving in the directions of arrows Za and Zb, the orientation thereof is changed by 90 degrees by a mechanism (not shown) so that the rear end of the paper P is secondary. It waits at a predetermined position until it passes through the transfer device 140. Further, the sheet P is released from the leading edge guides 160a and 160b, and enters the fixing device 100 while substantially maintaining its posture.

When the trailing edge of the sheet P passes through the secondary transfer device 140, the leading edge guides 160a and 160b support the trailing edge of the sheet so that the trailing edge of the sheet P does not fall and contact the peripheral members. As shown in FIG. 35B, the operation is performed again in the direction of arrow Y. Paper leading edge guide 1 at this time
The moving speeds of 60a and 160b are substantially equal to the paper conveying speed.

Next, when the rear end of the sheet P is conveyed by a predetermined amount, as shown in FIG. 35 (c), the sheet P operates again in the directions of arrows Za and Zb, and the sheet leading guides 160a and 160b.
0b is configured to return to the initial position. Also,
The trailing end of the sheet P is released from the sheet leading edge guides 160a and 160b, enters the fixing device 100 while maintaining its attitude substantially, and completes the fixing of the unfixed toner images held on both sides thereof.

As described above, in the twelfth embodiment, since the rear end side of the sheet is configured to be guided,
The posture of the paper can always be kept constant even for a paper having a high water content and a small stiffness. Therefore,
It is possible to obtain a very reliable device that does not cause a jam.

Thirteenth Embodiment FIGS. 36 and 37 show a thirteenth embodiment of a recording material conveying apparatus to which the present invention is applied. The sheet conveying device as a recording material conveying device according to the fifteenth embodiment is different from the twelfth embodiment.
However, unlike the twelfth embodiment, the paper tip guides 160a and 160b are, for example, comb-shaped guides as shown in FIG. Paper tip guides 160a, 16 having such a shape
By using 0b, the direction changing mechanism of the sheet leading end guides 160a and 160b required in the twelfth embodiment is not required. Therefore, it is possible to obtain a highly reliable device with a simple configuration and no occurrence of a jam as compared with the twelfth embodiment.

Next, the operation of the sheet conveying device will be described. The paper leading edge guides 160a and 160b are waiting for the paper P to be conveyed at the subsequent stage (initial position) of the secondary transfer device 140. Here, when the paper P is conveyed from a paper tray (not shown), a timer (not shown) is operated, and after a predetermined time elapses, the paper leading edge guides 160a, 160a
0b operates in the direction of arrow Y as shown in FIG. The paper tip guide 160a at this time,
The moving speed of the sheet P is substantially equal to the sheet conveying speed.
It reaches the contact part made in b or its vicinity.

Then, the sheet leading guides 160a, 160a
60b, when reaching near the nip area of the fixing device 100,
As shown in FIGS. 36 (b) and (c), arrows Za and
After moving in the direction of Zb, it stands by at a predetermined position until the rear end of the paper P passes through the secondary transfer device 140. Further, the leading end of the sheet P is a sheet leading guide 160a, 160b.
From the fixing device 10 while maintaining its attitude substantially.
It has rushed to zero.

Further, the rear end of the sheet P is
, The paper leading end guides 160a and 160b support the rear end side of the paper P so that the rear end of the paper P does not fall and contact the peripheral members, and as shown in FIG. Work in the direction. The moving speed of the paper guides 160a and 160b at this time is substantially equal to the paper transport speed.

Next, when the trailing edge of the sheet P is conveyed by a predetermined amount, as shown in FIG. 37B, the sheet P operates again in the directions of arrows Za and Zb, and the sheet leading guides 160a and 160a.
0b is configured to return to the initial position. Also,
The trailing end of the sheet P is released from the sheet leading edge guides 160a and 160b, enters the fixing device 100 while maintaining its attitude substantially, and completes the fixing of the unfixed toner images held on both sides thereof.

Fourteenth Embodiment FIGS. 38 and 39 show a fourteenth embodiment of a recording material conveying apparatus to which the present invention is applied. The paper transporting device as the recording material transporting device in the present embodiment is substantially the same as in the twelfth and thirteenth embodiments.
1a and 161b are further installed. By adopting such a configuration, it is possible to cope with sheets that are continuously conveyed, and the speed of the double-sided image forming apparatus can be increased.

Next, the operation of the sheet conveying device will be described. The paper leading edge guides 160a and 160b are waiting for the paper P to be conveyed at the subsequent stage (initial position) of the secondary transfer device 140. Here, when the paper P is discharged from a paper tray (not shown), a timer (not shown) is operated, and after a lapse of a predetermined time, the paper leading edge guides 160a, 160
0b operates in the direction of arrow Y as shown in FIG. The paper tip guide 160a at this time,
The moving speed of the sheet P is substantially equal to the sheet conveying speed.
It reaches the contact part made in b or its vicinity.

Then, the paper tip guides 160a, 160a,
60b, when reaching near the nip area of the fixing device 100,
As shown in FIGS. 38 (b), (c) to 39 (a), after moving in the directions of arrows Za, Zb, respectively, the sheet P is kept at a predetermined position until the rear end thereof passes through the secondary transfer device 140. Waiting. Further, the leading end of the paper P is
0a and 160b, and enters the fixing device 100 while substantially maintaining its posture.

Next, the rear end of the sheet P is
, The paper trailing edge guides 161a and 161b support the trailing edge of the paper P so that the trailing edge of the paper P does not fall and come into contact with the peripheral members, and as shown in FIG. Work in the direction. The moving speed of the paper trailing edge guides 161a and 161b at this time is substantially equal to the paper transport speed.

Next, when the rear end of the sheet P is conveyed by a predetermined amount, as shown in FIG. 39B, the sheet P operates in the directions of arrows Za and Zb, and the sheet rear end guides 161a and 161b
Is configured to return to the initial position. Further, the rear end of the sheet P is released from the sheet rear end guides 161a and 161b, and enters the fixing device 100 while maintaining its posture substantially, thereby completing the fixing of the unfixed toner images held on both sides. On the other hand, the paper leading edge guides 160a and 160b prepare for the conveyance of the next paper.

The present embodiment is configured as described above. By providing a plurality of paper leading edge guides, it is possible to cope with paper that is continuously conveyed, and to increase the speed of the double-sided image forming apparatus. Can be planned.

Fifteenth Embodiment FIG. 40A shows a fifteenth embodiment of a recording material conveying apparatus to which the present invention is applied. In the present embodiment, the sheet conveying device as the recording material conveying device includes cleaning devices 192a and 192 provided on the fixed type sheet leading edge guides 162a and 162b.
It is an example in which 2b is installed. In the drawing, the cleaning devices 192a and 192b are arranged at predetermined positions on the sheet grounding side of the sheet leading guides 162a and 162b so as to remove dust and the like on the sheet leading guides 162a and 162b. Here, when a sheet is not passed, the cleaning device 19 is driven by a driving mechanism (not shown).
2a and 192b are moved along the paper leading edge guides 162a and 162b,
a, 162b can be cleaned. As a result, it is possible to prevent dust from adhering to the paper leading edge guides 162a and 162b, prevent the paper from being caught by dust or the like and cause jam or smudge, and to surely transport the paper to the fixing device 100. Therefore, a highly reliable double-sided image forming apparatus can be obtained.

The present embodiment can be applied to various types of paper transport devices. For example, FIG.
Are paper guides 180a and 180b of a rotating belt type.
1 shows an example in which cleaning devices 190a and 190b are installed in the apparatus. Referring to FIG.
0a and 190b are pressed against the drive rolls 181a and 181b with a predetermined pressure, and the rotating belts 183a and 183b
It is arranged to remove dust and the like on b. With this configuration, it is possible to prevent dust from adhering to the rotating belts 183a and 183b, prevent paper from being caught by dust and the like, and prevent jams and smudges from being generated.
Can be transported reliably. Therefore, a highly reliable double-sided image forming apparatus can be obtained.

Further, FIGS. 41 (a) and (b) show that the cleaning device 1 is attached to the movable paper tip guides 160a and 160b.
This shows an example in which 91a and 191b are installed. In the figure, the cleaning devices 191a and 191b are arranged at predetermined positions on the movement trajectory of the sheet leading guides 160a and 160b so as to remove dust and the like on the sheet leading guides 160a and 160b. With this configuration, it is possible to prevent dust from adhering to the paper leading edge guides 160a and 160b, prevent paper from being caught by dust and the like, and prevent jams and smudges from being generated, and reliably transport the paper to the fixing device 100. It becomes possible. Therefore, as in the other examples, a highly reliable double-sided image forming apparatus can be obtained.

Although the embodiments of the present invention have been described with reference to the respective explanatory views, the paper guide system may be a belt system, a heating element system, a fixed guide system, a movable guide system, or the like. The image forming apparatus may be used in combination, and a more reliable image forming apparatus can be realized by combining. Further, in each of the embodiments of the present invention, a case has been described in which the transport direction of the paper is from the top to the downward direction and the horizontal direction, but the transport of the paper from the bottom to the upward or the transport in the oblique direction is described. It is easy to imagine that it can be applied. Further, the case where the unfixed toner images are present on both the front and back sides is described as the form of the sheet. However, it is needless to say that the present invention may be applied to the case where the unfixed toner image exists on only one side of the sheet.

Further, according to each of the embodiments of the present invention, a recording material conveying device can be configured as long as there is only a space area in which the sheet edge guide moves between the transfer device and the fixing device. Therefore, it is possible to reduce the size of the device.

In each of the embodiments of the present invention, the recording material on which the double-sided image has been transferred has been described as being conveyed to the fixing device. However, the present invention is applicable to the case where the recording material having been transferred only on one side is conveyed. Also applicable to Conventionally, when a recording material of one-sided transfer is conveyed, for example, in belt conveyance, one side of the recording material is conveyed by surface constraint, and the entire surface is constrained, and a phenomenon of waving at the leading end of the recording material has occurred. In the embodiment, by guiding and conveying the leading end of the recording material, it is possible to suppress such a waviness phenomenon, and it is possible to satisfactorily convey even a single-side transfer recording material.

[0101]

As described above, according to the present invention,
As the guide member of the recording material conveying device, a member that contacts only the edge of the recording material and guides the leading end position of the recording material to an appropriate rush position to the fixing unit is used, so that an unfixed image is carried. It is possible to reliably transport the recording material to the fixing unit without contacting the surrounding members, and
The posture in which the recording material enters the fixing means can be improved. Therefore, the recording material can be reliably guided to the fixing unit without narrowing the image carrying area and without causing the image to be disturbed. High image formation can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an outline of a recording material conveying apparatus according to the present invention and an image forming apparatus using the same.

FIGS. 2A to 2C are explanatory views showing another embodiment of a recording material conveying apparatus according to the present invention and an image forming apparatus using the same.

FIG. 3 is an explanatory diagram illustrating an outline of the image forming apparatus according to the first embodiment;

FIGS. 4A to 4C are explanatory diagrams illustrating an outline of an operation of the recording material conveying apparatus according to the first embodiment.

FIG. 5A is a diagram illustrating a recording material conveying device according to a second embodiment, and FIG. 5B is an explanatory diagram illustrating a modified embodiment thereof.

FIG. 6 is an explanatory diagram illustrating a recording material conveying device according to a third embodiment.

FIG. 7A is an explanatory diagram illustrating a recording material conveying device according to a fourth embodiment, and FIG. 7B is an explanatory diagram illustrating a configuration of a paper edge guide thereof.

FIGS. 8A and 8B are explanatory views showing a modified form of the recording material conveying apparatus according to the fourth embodiment.

FIGS. 9A and 9B are explanatory views showing still another modified example of the recording material conveying apparatus according to the fourth embodiment.

FIGS. 10A to 10D are explanatory diagrams illustrating an operation process of the recording material conveying apparatus according to the fifth embodiment.

FIGS. 11A to 11D are explanatory diagrams illustrating an operation process of a recording material conveying device according to a modification of the fifth embodiment. FIGS.

FIG. 12A is an explanatory view showing an outline of a recording material transporting device according to a sixth embodiment, and FIG. 12B is an explanatory view showing a modified form thereof.

FIG. 13 is an explanatory diagram illustrating an outline of an image forming apparatus according to a seventh embodiment.

14A to 14C are explanatory diagrams illustrating an outline of an operation of the recording material conveying apparatus according to the seventh embodiment.

FIG. 15 is a flowchart illustrating a flow of an operation of a sheet edge guide according to the seventh embodiment.

FIG. 16 is a flowchart illustrating a flow of an operation of a sheet edge guide according to the seventh embodiment.

FIG. 17 is an explanatory diagram showing an operation process (1) of a first example of the guide moving mechanism according to the seventh embodiment.

FIG. 18 is an explanatory diagram showing an operation process (2) of the first example of the guide moving mechanism in the seventh embodiment.

FIG. 19 is an explanatory diagram showing an operation process (3) of the first example of the guide moving mechanism in the seventh embodiment.

FIG. 20 is an explanatory diagram showing an operation process (4) of the first example of the guide moving mechanism in the seventh embodiment.

FIG. 21 is an explanatory diagram showing an operation process (1) of a second example of the guide moving mechanism in the seventh embodiment.

FIG. 22 is an explanatory diagram showing an operation process (2) of the second example of the guide moving mechanism in the seventh embodiment.

FIG. 23 is an explanatory diagram showing an operation process (3) of the second example of the guide moving mechanism in the seventh embodiment.

FIG. 24 is an explanatory diagram showing an operation process (4) of the second example of the guide moving mechanism in the seventh embodiment.

FIG. 25 is an explanatory diagram of a guide moving mechanism according to the seventh embodiment as viewed from the side.

FIG. 26 is a schematic explanatory diagram of a drive mechanism unit according to the first embodiment.

FIGS. 27A to 27D are explanatory diagrams showing an operation process in the eighth embodiment.

FIG. 28 is an explanatory diagram showing another application example of the seventh and eighth embodiments.

FIG. 29 is an explanatory diagram schematically showing a recording material conveying device according to a ninth embodiment.

FIG. 30 is an explanatory diagram showing another application example in the seventh, eighth, and ninth embodiments.

FIG. 31 is an explanatory diagram schematically showing an image forming apparatus according to a tenth embodiment.

FIGS. 32 (a) and 32 (b) are explanatory diagrams showing an operation process in the tenth embodiment. FIGS.

FIGS. 33A to 33C are explanatory diagrams showing the operation process of the recording material conveying device according to the eleventh embodiment.

FIGS. 34A to 34C are explanatory diagrams showing an operation process (1) of the recording material conveying device according to the twelfth embodiment.

FIGS. 35A to 35C are explanatory diagrams illustrating an operation process (2) of the recording material transporting device according to the twelfth embodiment.

FIGS. 36 (a) to (c) are explanatory diagrams showing an operation process (1) of the recording material conveying apparatus according to Embodiment 13. FIGS.

FIGS. 37A and 37B are explanatory diagrams showing an operation process (2) of the recording material transport device according to the thirteenth embodiment.

FIGS. 38A to 38C are explanatory diagrams illustrating an operation process (1) of the recording material conveying apparatus according to the fourteenth embodiment.

FIGS. 39A and 39B are explanatory diagrams showing an operation process (2) of the recording material transporting device according to the fourteenth embodiment.

FIG. 40A is an explanatory view schematically showing a recording material conveying apparatus according to Embodiment 15, and FIG. 40B is an explanatory view schematically showing a modified form thereof.

FIGS. 41A and 41B are explanatory diagrams illustrating an operation process of a recording material conveying device according to a modification of the fifteenth embodiment.

FIG. 42 is an explanatory diagram showing an outline of a conventional double-sided recording apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Guide member, 2 ... Transfer means, 3 ... Fixing means, 4 ... Recording material, 5 ... Retraction means, 6 ... Return means, 7 ... Proper rush position, 8 ... Standby position

 ──────────────────────────────────────────────────の Continuing on the front page (72) Mitsuo Yamamoto, Fuji Xerox Co., Ltd. 2274 Hongo, Ebina-shi, Kanagawa Prefecture (72) Yoshiya Mashimo 2274 Hongo, Hongo Ebina-shi, Kanagawa F Terms (reference) 2H072 AA32 AB07 AB19 AB20 CA01 CA02 3F049 AA01 FA01 LA02 LA05 LA07 LB03 3F101 FB07 FC11 LA02 LA05 LA07 LB03

Claims (13)

[Claims] An image forming apparatus includes: a transfer unit that transfers an unfixed image to a recording material; and a fixing unit that fixes the unfixed image transferred to the recording material. A recording material transport device, comprising: a guide member that contacts only an edge of the recording material and guides a leading end position of the recording material to a proper entry position into a fixing unit. apparatus. 2. The recording material transporting device according to claim 1, wherein the guide member defines a passage narrowing toward the downstream side on the upstream side in the transport direction of the recording material wider than the downstream side. Recording material transport device. 3. The recording material conveying apparatus according to claim 1, wherein the guide member moves from the transfer unit to the fixing unit to guide the recording material to the proper entry position. Material transfer device. 4. The recording material conveying apparatus according to claim 3, wherein the speed of the guide member in the conveying direction of the recording material is set to be equal to or faster than the conveying speed of the recording material. 5. The recording material conveying apparatus according to claim 1, wherein the guide member is variable in a width direction of the recording material orthogonal to the recording material conveyance direction, and supports the side edge of the recording material. A recording material conveying device, characterized in that: 6. The recording material conveying device according to claim 1, wherein the guide member is manually movable. 7. The trailing edge guide member according to claim 1, wherein the trailing edge of the recording material contacts and moves with the movement of the recording material to prevent the trailing edge of the recording material from falling down. A recording material transport device comprising: 8. The recording material transporting device according to claim 1, wherein the guide member is provided with a heat source for assumed wearing. 9. The recording material conveying device according to claim 1, wherein the guide member includes a cleaner. 10. The recording material conveying apparatus according to claim 1, further comprising an air flow control means disposed between the transfer means and the fixing means for controlling a conveying posture of the recording material by an air flow. Recording material transport device. 11. A recording material disposed between a transfer unit for transferring an unfixed image to a recording material and a fixing unit for fixing the unfixed image transferred to the recording material, wherein the recording material is transferred from the transfer unit to the fixing unit. A recording material transporting device, comprising: a guide member disposed at a predetermined set position, wherein only the edge of the recording material abuts and the leading end position of the recording material is guided to a proper entry position into the fixing unit; A retreating means for retreating the guide member at the set position to a retreat position when a leading end position of the material is guided to a proper entry position into the fixing means. 12. The recording material conveying apparatus according to claim 11, wherein the rear end position of the recording material reaches a position in the guide member that does not interfere with a standby position for waiting for the next recording material. A recording material transporting device further comprising a return means for returning the guide member to the standby position. 13. A transfer device for transferring an unfixed image to a recording material, a fixing device for fixing the unfixed image transferred to the recording material, and a transfer device disposed between the transfer device and the fixing device. 1-12
An image forming apparatus, comprising: the recording material conveying device according to any one of the above.