JP2915279B2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus using an electrophotographic system or an ink jet system, for example, an image recording apparatus such as a printer, a facsimile or a copying machine, and more particularly to a multiplex image recording apparatus.

[0002]

2. Description of the Related Art Heretofore, as an apparatus for performing recording by the above-described method while transporting a recording paper or the like as a recording medium, one having the following configuration is generally known.

FIG. 8 shows an example. The device is roughly divided into an image input unit 90R and an image output unit 90P.
The image input unit 90R is a device for inputting image information for recording, performing various processes, and transmitting the image signal to the image output unit. The image output unit 90P
Is an image forming section 91 for forming a recording image in accordance with the above signal, a plurality of sheet feeding units 92A, 92B, 92C for stacking recording sheets P and sending them out one by one, and sent out from a sheet feeding unit. Rolled recording paper into registration rollers 9
6, a transfer drum 9 for transferring to the image forming unit while holding the recording paper sent from the registration rollers and transferring the image onto the recording paper.
3. It comprises a fixing unit 94 for fixing the image recorded on the recording paper and a control unit 95 for controlling all operations in these devices.

Next, the recording operation will be described in detail step by step. When the operation of the apparatus is started, one sheet of recording paper is first fed from one of the paper feeding units, and then fed to a registration roller by the pre-registration conveyance unit. At this time, the roller is stopped, and the pre-registration conveying unit continues to convey for a short time after the leading edge of the recording paper hits this roller. Then, after the recording paper forms a predetermined loop (hereinafter, referred to as a pre-registration loop), the transport unit stops. Thereafter, the roller (and the pre-registration conveying unit) rotates in synchronization with the image recording start signal, and sends out the recording paper onto the transfer drum (this operation can form an image at a predetermined position on the recording paper). The recording paper is conveyed to the image transfer area while being held on the transfer drum, and the image formed by the image forming unit is transferred and recorded on the surface. Here, as a method of holding the transfer drum on the transfer drum, there are several methods such as electrostatic suction and air suction on a transfer medium made of a thin dielectric film or the like. When the recording on the recording paper is performed, the transfer drum conveys the recording paper to the vicinity of the fixing unit, and sends the recording paper to the unit while separating the leading end of the paper. Then, heat and / or pressure is applied to fix the toner image on the recording paper, and then the recording paper is discharged out of the apparatus via a paper discharge unit.

Here, in an apparatus of the type having a plurality of paper feed units as described above, if each unit such as a transfer drum and an image forming unit is arranged at an optimum position while reducing the size of the apparatus, it is general. In short, it is inevitable that the paper path becomes a crank shape as shown in the figure. Then, the pre-registration loop space is usually provided so as to form a loop toward the inside of R near the curved portion R in front of the resist as shown in FIG. This is because the paper is transported along the outside of the R, and it is difficult to provide a space further outside the paper.

In the case of an apparatus of the type in which a recording paper is wound around a transfer drum and an image is transferred onto the surface of the transfer drum as described above, if the paper held on the drum has a slight floating or the like, the image density changes and The transfer image may be adversely affected, such as transfer omission. In order to avoid this problem, for example, a curling mechanism 98 for curling the paper is provided in the conveyance section before the registration, and the paper is arranged so as to easily follow the transfer drum.

[0007]

However, the above-described apparatus has the following problems. The amount of curl that is likely to follow the transfer drum once applied to the paper in the pre-registration conveyance unit is changed by the pre-registration loop. For example, in this apparatus, the paper has a loop shape as shown in FIG. 9, and the paper is bent three times while changing the direction of the curvature.
Then, the curl amount of the paper eventually decreases, and when the paper is along the transfer drum, the leading end and the trailing end of the paper tend to float off the drum, and there is a possibility that image omission or the like may occur. Alternatively, in some cases, a phenomenon in which the paper is peeled off from the drum may be considered.

In order to prevent this, it is conceivable to increase the curling amount more than necessary in anticipation of the change due to the loop. However, it is almost impossible to uniformly determine the curling amount for all papers having different thicknesses or stiffnesses ( For example, the higher the rigidity of the paper, the larger the amount of change in curl due to the loop, the thinner the paper, the smaller the amount of change, and the amount of change is not stable.) Also, curling more than necessary requires a great performance of the curling mechanism, which is not efficient. Strictly speaking, since the normal pre-registration loop is formed after the center of the paper, it does not uniformly affect the entire surface of the paper, and the leading end is hardly affected. From the above, it is desirable that the pre-registration loop does not affect the curl as much as possible.

Taking this point into consideration, one method is to increase the loop space as much as possible and reduce the curvature even with the same loop amount. However, it is difficult to secure the space and the device becomes larger. In addition, there is a limit to simply reducing the loop amount because of the original purpose of removing the paper resist. In particular, the increase in the number of paper feed units, which has become common in recent years, has led to an increase in the length and complexity of the paper path to the registration roller, which tends to increase the variation in paper conveyance timing, and absorbs this. For this reason, some loops are indispensable.

The present invention has been made in order to solve the above-mentioned problems of the prior art. It is an object of the present invention to maintain a good image quality without affecting the curl of any kind of sheet material. It is another object of the present invention to provide an image recording apparatus in which a pre-registration loop for maintaining the holding performance of a transfer drum with respect to a sheet material is provided, a stable registration of the sheet material is performed, and the apparatus is prevented from being enlarged. .

[0011]

SUMMARY OF THE INVENTION According to the present invention, there is provided a conveying section for feeding a sheet material supplied from a paper feeding section to a registration section through a paper path having a curved portion, and for correcting skew of the sheet material. A resist section for stopping the leading end of the sheet material at one end to form a loop and sending it to the image forming section, and a drum downstream of the resist section for holding the sheet material on its surface and transporting the sheet material to the image forming section And the outside of the paper path curved portion is the upstream side and
Two independently movable guides provided on the downstream side
Guide member on the upstream side.
The guide member on the downstream side is supported rotatably on the fulcrum,
The movable guide member is rotatably supported on the fulcrum.
A loop space is formed by movement.

[0012]

[0013]

[0014]

In the image recording apparatus constructed as described above, the outside of the paper path curved portion is provided on the upstream side and the downstream side.
It is composed of two independently movable guide members.
The upstream guide member is rotatably supported on the upstream side as a fulcrum.
The guide member on the downstream side is rotatable around the downstream side as a fulcrum.
Guide section when the leading edge of the sheet material enters
The rotational moment generated by the force in the direction of pushing the material is
Guide member when forming a loop of sheet material
The moment generated when pushing out is increased
The fulcrum of two guides is selected, and the sheet material forms a loop
When the guide member swings, the sheet material enters
Occasionally, the guide member swings under the pushing force of the sheet material.
It can be configured not to.

[0015]

[0016]

[0017]

【Example】

(First Embodiment) A first embodiment of the present invention will be specifically described with reference to FIG. Hereinafter, an electrophotographic method is used as an image forming method, and a color image output apparatus in which the present invention is considered to be particularly effective will be described.

This embodiment has a digital color image reader section at the top and a printer section at the bottom. In the leader section,
The original 30 is placed on a platen glass 31 and an exposure lamp 32
To perform exposure scanning. The reflected light image from the original 30 is condensed on the full-color sensor 34 by the lens 33 to obtain a color-separated image signal. This signal passes through an amplifier circuit (not shown) (not shown), is subjected to various processes in a video processing unit, and then sent to a printer unit.

The printer section has the following configuration. A photosensitive drum 1 as an image carrier is pivotally supported at its center, and is driven to rotate in the direction of the arrow. A pre-exposure lamp 11, a primary charger 2, an exposure optical system 3, such as a laser, facing the outer peripheral surface of the photosensitive drum 1 in the direction of its rotation;
Potential sensor 12, developing device 4, on-drum light amount detecting means 1
3, a transfer drum 5, and a cleaning device 6 are arranged in this order.

The pre-exposure lamp 11 and the primary charger 2 apply a uniform amount of charge to the surface of the photosensitive drum 11. Next, the optical system 3 exposes a light beam such as a laser beam modulated in accordance with the recording image signal to the (E) photosensitive drum through the polygon mirror 3A, the lens 3B, and the like, thereby forming an electrostatic latent image thereon. To form Further, a developing device 4 (in the present device, a developer of four colors such as yellow, cyan, magenta and black
Four devices 4 each of which contains toner).
Y, 4C, 4M, and 4Bk are arranged side by side, and are configured to be movable so as to be selectively brought closer to the photosensitive drum by the operation of the eccentric cams 24Y, 24C, 24M, and 24Bk. ) To visualize the electrostatic latent image. On the downstream side of the image transfer area, the cleaning device 6 cleans the drum surface by scraping off the toner remaining on the photosensitive drum without being transferred to the recording paper as a sheet material. By the process described above, image formation with toner is performed.

This apparatus has a three-stage cassette paper feeder (referred to as upper, middle, and lower) and one manual paper feeder. The middle sheet feeding will be described (the upper and lower steps are almost the same, and the description is omitted). The sheet feeding unit 40 includes a cassette 41 for storing the recording paper P as a sheet material, and a recording paper from inside the cassette. Rollers 42A, 43B, and 45A, 45B, 45C, and paper guides for transporting the recording paper sent from the pickup rollers to the transfer transport unit 50.
The manual feed unit includes a manual feed tray 41T and a paper feed roller 42M.
(And a separation pad (not shown)).

The transfer and transport unit 50 is roughly divided into a transport section 50A and a transfer drum 5. The transfer section 50A is shown in FIG.
It will be described based on. Guides 48A, 48B, 48 for guiding recording paper inherited from the paper feeding unit 40
C, 48D, 48E, and transport rollers 46A, 46
B, 46C, 47A, 47B, and further, the recording paper is transferred to a transfer drum 5 (described later) in accordance with the image forming timing of the image forming unit.
And a suction guide 48F, 48G for guiding the recording paper at that time.
Here, the transport rollers 46A, 46B, 46C have a curling function. The guides 48B and 48D are formed in an R shape to change the traveling direction of the recording paper, and are supported so as to be swingable in the direction of the arrow as shown in the figure (these are referred to as movable guides). This is to secure a loop space for the paper P generated when the leading end of the recording paper is temporarily stopped by the registration roller. The transfer drum 5 will be described with reference to FIG. Connecting the annular members 55A at both ends to the connecting members 55B
The transfer drum 5 is formed by wrapping a recording paper holding sheet film 55S (for example, PET <polyethylene terephthalate> or PVdP <polyvinylidene fluoride> is used as the material thereof) in a cylindrical shape around the frame 55F connected by the above.

At the position where the recording paper sent from the registration roller enters the transfer drum, the suction roller 5G is moved to the transfer drum 5
A backup member and a suction charger 5C for opposing the pressing force of the roller are disposed on the opposite side of the film 55S of the suction roller with the film 55S of the suction roller interposed therebetween. In the image transfer area where the photosensitive drum and the transfer drum face each other, a transfer charger 5B is arranged on the back of the film. On the downstream side, a separating member for separating the recording paper, specifically, the charge removing charger 5H and the separating claw 8
A, a film lifting roller 8B and the like are provided, and subsequently, film discharging chargers 5D and 5E are disposed across the film. Further downstream, a brush roller 14 and a corona discharger or a brush type static eliminator 15 for cleaning toner and paper dust adhered to the recording paper holding surface of the film, and oil used in a fixing unit is used for double-sided recording. At times (described later), the recording paper may adhere to the film surface through the recording paper, and an oil removing roller 16 and a backup brush 17 for cleaning it are provided.

Here, the transfer drum section 5 is configured to be able to be separated from and contacted with the photosensitive drum, and is separated except during normal operation. This is to prevent the transfer drum and the photosensitive drum from being in contact with each other for a long time, and to prevent the recording paper or the like from contacting the photosensitive drum and damaging the surface during the jam processing. Further, in this apparatus, the transfer / conveyance unit 50 is configured to be able to be pulled out from the main body by the sliders 62A and 62B. This is to make jam clearing or maintenance more reliable and easier.

The fixing unit 9 includes a fixing roller 9A having a heat source such as a halogen heater therein, a pressing roller 9B pressed against the roller (the roller may also be provided with a heat source), and the roller pair. The conveyance belt 9C and the entrance guide 9D for guiding the recording paper to the nip portion, and the paper discharge roller 9E for further guiding the recording paper discharged from the roller pair to the outside of the apparatus.

Here, the present apparatus has a mechanism for automatically recording an image on both sides of the recording paper. This is described below. A conveyance path switching guide 19 is provided immediately downstream of the fixing unit 9 so that, after fixing, one of a paper path discharged outside the apparatus and a paper path for double-sided recording is automatically selected. . The duplex paper path is
Conveying vertical path 20, reversing path 21A, reversing roller 21B,
The recording paper, which is composed of an intermediate tray 22 and the like, is guided to the reversing path 21A, and the recording paper is retracted by the reverse rotation of the reversing roller 21B, with the trailing end at the time of being fed, exiting in the opposite direction to the direction in which the recording paper was fed. Is stored. Thereafter, paper is fed again from the intermediate tray, and an image is formed on the other surface of the recording paper by the above-described image forming process. Here, a plurality of guides are selectively moved up and down in the guide portion 23 on the upper portion of the intermediate tray according to the size of the recording paper to be stored. As a result, paper of any size can be stored and stacked at the top of the intermediate tray.

The control unit includes a control board, a motor drive board, and the like for controlling the operation of the mechanism in each unit.

Next, a description will be given in accordance with the operation of the apparatus (a case where paper is fed from a middle paper feeder will be described as an example).

When the image forming operation start signal is issued, first, the cam 71 makes a half turn, and accordingly, the transfer drum 5 swings and moves to the operation position, and rotates in synchronization with the photosensitive drum 1. At the same time, the recording paper P is sent out one by one from the cassette 41 by the pickup roller 42. Then, the paper feed rollers 43A and 43B and the transport rollers 45B and 45C
As a result, the recording paper is guided between the paper feed guides and is transported to the transport unit 50A. In the transport unit, the recording paper is first curled by a predetermined amount in a direction in which the recording paper winds around the transfer drum when passing through the curling rollers 46A, 46B, and 46C. Thereafter, the sheet is conveyed to the registration roller 44 while changing the conveyance direction by the action of the conveyance roller 47 and the guide member. At this time, the registration roller 44 is stopped, and the leading end of the recording paper strikes the nip. After a lapse of a certain time, the driving of the transport roller is stopped. Then, a loop is generated in the recording paper during that time, and a loop space R required for the loop is formed by a movable guide 48 as a guide member.
B, 48D (the recording paper is automatically spread out at the waist [R in FIG. 2]). Here, in this apparatus, the pre-registration loop amount is set to 7 mm (this value indicates the amount of recording paper further fed after the leading edge of the recording paper hits the registration roller 44). This is necessary in order to correct the recording paper when it reaches the registration section skewed. Thereafter, after a certain period of time based on the timing at which the image forming unit starts forming an image, the registration roller 44 and the transport roller start rotating. The rotation timing is set so that the recording paper and the toner image on the photosensitive drum exactly coincide in the image transfer area.

When the recording paper enters and contacts the transfer drum 5, the recording paper is electrostatically attracted onto the recording paper holding sheet film 55S by the action of the corona discharge from the attraction charger 5C and the action of the attraction roller 5G. Usually, it is separated from the transfer drum to reduce the load, and is pressed against the transfer drum only when the recording paper enters.) The transfer drum rotates in synchronization with the photosensitive drum, and the recording paper is conveyed to the image transfer area while being held thereon. Then, after the toner image formed on the photosensitive drum by the above-described process is transferred to the surface by the transfer charger 5B, the recording paper is transported to the separation unit. Here, since one color image is transferred at a time, the recording paper is separated by a later-described operation in the case of a single-color image, but the separation operation is not performed in the case of forming a multi-color image without performing the separation operation. And is transported again to the transfer area. Then, the next toner image is further transferred onto the previous image, and this process is repeated a required number of times (the brush roller 14 and the like are supported so as to be able to be separated from and contact with the surface of the transfer drum, and at least the multiple transfer They are separated in the process.).

When the operation is completed, the recording paper and the holding sheet film 55 are actuated in the separation section by the action of the charge removing charger 5H.
The suction force between S is reduced, and the recording paper is separated from the transfer drum by the subsequent operation of the separation claw or the like.

The recording paper separated from the transfer drum is conveyed to a fixing roller portion by a conveyance belt 9C, and is guided on an entrance guide 9D accurately to the nip portion. Then, the toner image is fixed on the recording paper surface by the heat of the roller 9A. Thereafter, the recording paper is conveyed by the paper discharge rollers 9E, and the recording paper is discharged out of the apparatus. Finally, the transfer drum separates from the photosensitive drum (retreat position), and the apparatus stops.

Here, the case of double-sided recording will be described. When the switching guide 19 operates, the recording paper on which one side has been recorded and fixed is guided to the transport vertical path 20, and thereafter, the recording paper is reversed by the reversing roller 21 B via the reversing path 21 A and stored in the intermediate tray 22. After the required number of sheets are stacked, the single-sided recording paper P 'is sent out one by one from the intermediate tray by the pickup roller 25, and is conveyed to the conveyance unit 50A by the paper feed rollers 26A and 26B. Thereafter, an image is recorded on the other side of the recording paper by performing the same steps as described above. Finally, the recording paper is discharged outside the apparatus without operating the switching guide 19.

In this apparatus, the pre-registration loop space is formed by swinging two guides outside the curved portion of the paper path, which will be described in detail below.

As described in the conventional example, when the loop is formed toward the inside of the curved portion, the recording paper bends several times, and its curvature becomes small, so that the curling effect by the curling roller is large. On the other hand, if it is formed on the outside, it has a large curvature and it only needs to bend once, so that its effect is not greatly reduced, and a constant curl amount can be stably maintained. Also, 2
The reason for adopting the configuration of the single swing guide will be described below. First, when the recording paper strikes the registration roller and forms a loop, it must swing against the force. On the other hand, when the leading edge of the recording paper enters, the pressing force of the guide works.
The guide must not swing due to this. Further, this must be always established for various types of recording paper having different rigidities. Here, the direction of the curl applied by the curling roller is opposite to the bending direction of the guide.In particular, as described above, the recording paper having higher rigidity has a larger curling amount. The pushing force of the guide becomes larger than the increase in stiffness. After all, it is difficult to satisfy the above-mentioned conditions with a configuration in which one guide swings, and in this embodiment, two swing guides are used. As a result, as shown in FIG. 4A, the rotational moment Mf generated by the force in the direction of pushing the guide when the leading edge of the recording paper enters is as small as possible (Fb and Fd in the figure are the forces in the recording paper conveyance direction. Mf is generated from the component force in the direction in which the guide is rotated). On the other hand, as shown in FIG. 4B, the moment Mr generated when the guide is expanded when forming the recording paper loop is increased so that the two sheets become large. The swing center position of the swing guide can be selected, and the above condition can be achieved.

Next, the structure of the guide section will be specifically described with reference to FIG. Here, the fixed guides 48C, 4 inside the curved portion
8E and the roller 47A are omitted. Movable guide 48
B, the movable guide 48D is supported on a unit side plate (not shown) so as to be swingable about central axes 48K and 48L, respectively. Then, they are urged upward by spring (48M, 48N) forces, and stop against stoppers (48V, 48W) protruding from the unit side plate. When the recording paper enters, the biasing force wins and the guide does not swing, then when the recording paper forms a loop, lose and set the spring force so that the guide swings as shown by the two-dot chain line in the figure. I have. Actually, the action force at the time of paper entry is the guide 4
8B, and the loop space is formed mainly by the swing of the movable guide 48D.
The urging torque of the movable guide 48B is set slightly higher than that of 8D. However, the setting of the biasing torque is not limited to this, because it differs depending on the configuration of the system to be implemented, the shape of the paper path, and the like.

When the present invention is implemented with the above-described configuration, the following effects are obtained.

After the recording paper was curled, the curl was not significantly reduced by the loop before the registration, and a stable curl amount could be maintained. As a result, it is possible to hold the recording paper on the transfer drum in a good state without floating or the like, and to obtain a high-quality image without transfer omission or the like. Furthermore, it became possible to cope with many types of recording paper having different stiffness, and it was possible to prevent an increase in the size of the apparatus.

(Second Embodiment) In the first embodiment, the loop amount before registration is set to 7 mm. In this embodiment, the curl of the recording paper is further stabilized by reducing the loop amount. planned. The purpose of the pre-registration loop is to generate a force that pushes the leading edge of the recording paper when correcting the skewed recording paper against the registration roller nip. For this purpose, there must be some degree of freedom not only in the traveling direction but also in the width direction (perpendicular to the traveling direction) in the portion from the loop portion to the leading end of the recording paper. However, compared to the case where a loop is formed inside free space toward the inside of the paper path curved part, the structure formed outside while pushing and expanding the guide is because the surface of the recording paper is in contact with the guide. The degree of freedom in the width direction of the recording paper is limited by friction. Furthermore, the spring force of the movable guide becomes a force for pushing the recording paper, but the side of the recording paper that first reaches the registration nip due to skew increases the amount of loop as compared to the opposite side, and as a result, the spring of the guide The force acts only on the side that first hit the nip (the guide is a rigid body) and does not contribute much to the correction of skew.

Based on the above, the present invention was implemented using a movable guide having the following configuration. The details of the configuration are shown in FIG. 6 (those having the same functions as in FIG. 5 are denoted by the same symbols, and description thereof is omitted).

The movable guide 48D is further connected to a guide portion 48P.
And a guide arm 48Q.
Joined. For this purpose, the guide portion 48P is rotatably supported on the guide arm about the step screw, and the spring is hung on both sides of the guide. In the direction of rotation by the spring force, the rotation is restricted by the projection 48S of the guide portion abutting on the guide arm. Furthermore, a sheet 48T having a low coefficient of friction with respect to the recording paper is provided on the guide surface.
(For example, a high-density polyethylene sheet).

The feature of this guide is that the amount of loop varies in the width direction of the recording paper when the recording paper strikes the registration roller and forms a loop in a skewed state. Is configured. That is, as shown in FIG. 7, the guide arms at both ends can swing substantially independently (in the figure, if the swing angle of the guide arm on the A side is α and that on the B side is β, α> β
The guide can also be brought into contact with the smaller side of the loop of the recording paper to apply the urging force. As described above, the urging force of the guide acts almost uniformly in the width direction of the recording sheet (regardless of the skew of the recording sheet) as a force for abutting the leading end of the recording sheet against the registration nip, and also acts in the width direction for the sheet 48T. Since the degree of freedom of the recording paper is improved, the skew correction ability is improved as compared with the previous embodiment. For this reason, the loop amount of the recording paper can be reduced (specifically, 4 to 5 m).
m) As a result, it was found that the curl amount of the recording paper was further reduced, and the recording paper was more stable. In addition, the performance of the curling roller can be kept low, but this leads to an increase in service life and a reduction in energy.

Although the movable guide forming the loop space has been described as a swing type, the present invention is not limited to this. For example, the movable guide may be formed by parallel movement. The guide may be moved by the above actuator. Further, although the description has been given of the configuration of the three rollers as the curling mechanism, the present invention is not limited to this, and the effect is the same with any configuration such as a type in which the roller is pressed against the belt.

Although the holding of the recording paper on the transfer drum has been described above by electrostatic attraction, the present invention is not limited to this, and a mechanical holding method such as a gripper may be used. In addition, the image forming means is not limited to electrophotography, such as an inkjet method and a thermal transfer method.
Any device may be used as long as it requires a recording paper transport mechanism.

[0045]

According to the present invention, a conveying section for feeding a sheet material supplied from a paper feeding section to a registration section through a paper path having a curved section, and a sheet section for correcting skew of the sheet material. An image having a resist section for stopping the leading end to form a loop and sending it to the image forming section, and a drum downstream of the resist section for holding a sheet material on its surface and transporting the sheet material to the image forming section. In the recording apparatus, the outside of the paper path curved portion is provided on the upstream side and the downstream side.
Composed of two independently movable guide members.
The guide member on the upstream side is rotatable around the upstream side as a fulcrum.
And the guide member on the downstream side rotates around the downstream side as a fulcrum.
Because it is freely supported, the guide
The rotational moment generated by the force in the direction of pushing the
Guide as small as possible to form loops in sheet material
Moment generated when members are expanded is increased
Select the fulcrum of the two guides and make the sheet material loop
When forming, the guide member swings and the sheet material enters
When the guide member swings, it loses the pushing force of the sheet material.
It can be configured not to move.

Therefore, for sheet materials having different rigidities,
Also, the loop shape before the cash register always becomes gradual,
The transfer material can be held on the transfer drum in a stable state.
It works. As a result, there is no image shift or missing image.
Good transfer images are always obtained. Also, the equipment size is large
Does not change.

[0047]

[Brief description of the drawings]

FIG. 1 is a configuration sectional view of an apparatus embodying the present invention.

FIG. 2 is a configuration diagram showing a transport unit of the present invention.

FIG. 3 is a configuration diagram illustrating a transfer drum of the present invention.

FIG. 4 is an explanatory diagram showing a force relationship acting on a swing guide in the first embodiment.

FIG. 5 is a perspective view showing a configuration of a swing guide according to the first embodiment.

FIG. 6 is a perspective view showing a configuration of a swing guide according to a second embodiment.

FIG. 7 is an explanatory view showing characteristics of a swing guide according to a second embodiment.

FIG. 8 is a cross-sectional view illustrating a configuration of a conventional device.

FIG. 9 is an explanatory view showing a pre-registration loop of the conventional apparatus.

[Explanation of symbols]

 5 Transfer drum 40 Paper feed unit 44 Registration rollers 45C, 47A, 47B Transport rollers 46A, 46B, 46C Curling rollers 48A, 48C, 48E, 48G Fixed guides 48B, 48D Movable guides (guide members) 50A Transport unit P before registration P 'Recording paper (sheet material) R Loop space

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G03G 15/00 515-534 G03G 13/14-13/16 G03G 15/14-15/16 103 B65H 5 / 00 B65H 5/04 B65H 5/08-5/20 B65H 5/24-5/38 B65H 29/52

Claims (1)

(57) [Claims] 1. A conveying unit for feeding a sheet material supplied from a paper feeding unit to a registration unit via a paper path having a curved portion, and temporarily stops the leading end of the sheet material to correct skew of the sheet material. In the image recording apparatus having a resist unit for sending to the image forming unit, and a drum downstream of the resist unit and holding a sheet material on its surface and transporting the sheet material to the image forming unit, The outer side of the paper path curved portion is constituted by two independently movable guide members provided on the upstream side and the downstream side, and the upstream side guide member is rotatably supported on the upstream side as a fulcrum. An image recording apparatus, wherein a downstream guide member is rotatably supported on the downstream side as a fulcrum, and a loop space is formed by movement of the movable guide member.