JP3340009B2 - Paper transport 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 paper transport apparatus for transporting paper (sheet medium) such as transfer paper placed on a transport belt , and more particularly to, for example, printing a plurality of different colors one on top of another. The present invention relates to a sheet conveyance device suitable for use in a sheet conveyance system in a color image forming apparatus such as an electrophotographic printer that forms a color image on a sheet by performing the above operation.

[0002]

2. Description of the Related Art For example, an electrophotographic printer (color image forming apparatus) having a conventional paper transport device is generally configured as shown in FIG. That is, the electrophotographic printer 1 shown in FIG.
It comprises paper cassettes 3, 4, paper sending section 5, paper discharge section 6, paper stacker 7, power supply / control section 8, and the like.

In this electrophotographic printer 1, transfer paper (sheet medium, paper) 18 to be printed is stored in paper cassettes 3 and 4, and is sent out by a paper sending unit 5 during printing. The paper is guided by the transport rollers 23 along a transport guide (transport path) 24 and fed into the color print engine 2. The transfer paper 18 that has been subjected to color printing in the color print engine 2 configured as described below is guided by the transport rollers 23 along the transport guide (transport path) 24 via the paper discharge unit 6, and is fed to the paper stacker. It is discharged to 7.

The power supply / control unit 8 has a function of supplying power necessary for the operation of the printer 1 to each unit and a function of controlling the entire operation of the printer 1 including a printing operation by the color print engine 2. Things. Further, in the printer 1 shown in FIG. 9, a double-side mechanism (not shown) for reversing the transfer paper 18 having been printed on one side on the paper discharge unit 6 side, in order to perform double-sided printing on the transfer paper 18, A transport guide (transport path) 24 </ b> A for feeding the transfer paper 18 inverted by the double-sided mechanism to the color print engine 2 again is provided.

[0005] Generally, the color print engine 2 for printing a color image includes four printing units 10.
Y, 10M, 10C, 10K, a fixing unit 16, and a paper transport unit (paper transport device) 9 composed of a resin-made endless transport belt (electrostatic attraction belt, transfer belt) 17 for transporting the transfer paper 18 And Printing unit 10Y, 1
0M, 10C, and 10K are yellow (Y),
In order to transfer toner images of each color of magenta (M), cyan (C), and black (K) onto transfer paper 18, photoconductor (transfer drum, latent image carrier) 11, precharger 12, optical unit 13,
A developing unit 14 and a transfer roller 15;
These printing units 10Y, 10M, 10C, 10K
Are arranged substantially in parallel along the conveyor belt 17.

Here, the photosensitive member 11 is driven to rotate by a drive motor (not shown). The pre-charger 12 uniformly charges the surface of the photoconductor 11, and the optical unit 13 projects image light corresponding to recording information (information on print data) onto the surface of the photoconductor 11. is there. The optical section 13 exposes a pattern corresponding to print data on the surface of the photoconductor 11 to form an electrostatic latent image.

The developing unit 14 develops an electrostatic latent image formed on the surface of the photoconductor 11, and actually supplies a toner to the surface of the photoconductor 11 to form a visible toner image. (Developed image, developed image) is formed to perform development. The transfer roller 15 is disposed so as to face the photoconductor 11 with the conveyance belt 17 (that is, the transfer paper 18) interposed therebetween, and is conveyed by the conveyance belt 17 between the transfer roller 15 and the photoconductor 11. By sandwiching the transfer paper 18, the toner image on the photoconductor 11 is transferred to the transfer paper 18.
It is designed to be transcribed upward.

[0010] Further, the fixing unit 16 is provided with each printing unit 1.
When the transfer paper 18 to which the toner images of each color are transferred by 0Y, 10M, 10C, and 10K is sent, the toner image on the transfer paper 18 is fixed to the transfer paper 18 by heat, pressure, light, or the like. It is to make it. On the other hand, the paper transport unit 9 transports the transport belt 17 to a driving roller 19, a driven roller 20, and a tension applying roller (tensioner).
Endlessly wound around the outer circumferences of the motor 21 and 22, the motor is driven by transmitting the rotational driving force of a driving motor (not shown) from the driving roller 19, and is charged by a charger (not shown). The transfer paper 18 is electrostatically attracted to the outer surface of the transport belt 17 (the surface facing the photoreceptor 11) and transported to the printing units 10Y, 10M, 10C, and 10K in order.

The printing units 10Y, 10M, 1
Immediately before the image transfer point on the transfer paper 18 at 0C and 10K (the image transfer point by the photoconductor 11 and the transfer roller 15), a registration roller (not shown) for aligning the leading end of the transfer paper 18 is provided. ing. With the above configuration,
In the electrophotographic printer 1 shown in FIG.
The paper is sent from the paper cassette 3 or 4 to the transfer belt 17 of the paper transport unit 9 in the color print engine 2 via the paper delivery unit 5 and is transported by the transport belt 17 to print units 10Y, 10M, 10C, and 10C. 10K
, And is sent to the fixing unit 16.

These printing units 10Y, 10M, 1
0C and 10K, the transfer paper 18
Are transferred toner images of respective colors (Y, M, C, K).
The toner image is fixed to the transfer paper 18 when the transfer paper 18 passes through the fixing unit 16. As described above, in the printing units 10Y, 10M, 10C, and 10K, a color image is formed on the transfer paper 18 by sequentially printing different colors on the transfer paper 18.

[0011]

In the paper transport section 9 of the printer 1 described above, the driving roller 19, the driven roller 20, and the tension applying roller 21,
A flat conveyor belt (flat belt) 17 having a thickness of, for example, about 0.1 mm is wound around the outer periphery of the end 22 in an endless manner.

When the transfer paper 18 is transported by using the transport belt 17, the transport belt 17
Due to the accuracy of the center distances 9 and 20 and the difference in the circumferential length of the conveyor belt 17 in the width direction, a difference in tension in the width direction may occur, and the conveyor belt 17 may skew. When the transport belt 17 is skewed, the transfer paper 18 adsorbed on the transport belt 17 is
Of the printing unit 10Y, 10M, 10C, 1
When the toner image is transferred to the same transfer paper 18 by the photoconductor 11 and the transfer roller 15 at 0K, the transfer position of the toner image is determined by each of the printing units 10Y, 10M, 1
There is a possibility that the displacement may occur at 0C and 10K. In particular, in an apparatus that forms a color image by superimposing a plurality of colors, the above-described subtle misregistration appears as color misregistration, and the print quality of the color image deteriorates.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and reliably prevents skew of a transport belt and transports paper (sheet-like medium) such as transfer paper while maintaining the paper at a precise transport position. It is an object of the present invention to provide a paper transport device that is capable of performing the above.

[0014]

In order to achieve the above object, a paper transport apparatus according to the present invention supports a transport belt by a plurality of rollers including a driving roller and a driven roller.
When the sheet-shaped medium is transported by driving the transport belt by a driving roller while holding the sheet-shaped medium on the transport belt, a flange is protruded from at least one of both side edges of the transport belt, and the transport is performed. A regulating roller that can contact the side end surface of the flange while supporting the belt to regulate the position of the conveyor belt, and a pressing roller that can press the side edge of the conveyor belt provided with the flange against the regulating roller , The flange is fitted to the end of the regulating roller.
And forming a matching groove over the entire circumference of the regulating roller.
In addition, the regulating roller adjusts the radius of the portion outside the groove portion to the
By the thickness of the conveyor belt rather than the radius of the inner part of the groove
The pressing roller is formed to have a large size.
To press the side edge uniformly against the regulating roller,
The outer peripheral surface of the regulating roller on both sides of the groove portion pushes the pressing member.
It is characterized in that both ends of the roller are supported (claim 1).

At this time, the height of the flange may be set to be larger than 1/15 of the radius of the regulating roller (Claim 2), or the regulating roller may be a roller other than the driving roller (Claim 2). 3) A tapered surface may be formed over the entire periphery of the regulating roller at the edge of the end of the regulating roller that abuts on the flange .

In the paper transport apparatus of the present invention configured as described above, the regulating roller supports the transport belt while supporting the transport belt.
By contacting the side end surface of the flange protruding from the conveyor belt, the position of the conveyor belt is regulated, and the skew of the conveyor belt can be prevented. In addition, the pressing roller presses the side edge of the conveying belt against the regulating roller, so that the flange of the conveying belt smoothly contacts the regulating roller, and the flange is regulated by the skew force of the conveying belt. An attempt to ride on the end of the roller can be forcibly suppressed . And hold down
Roller at both ends.
The side edges of the roller uniformly against the regulating roller
The holding roller against the edge of the end of the regulating roller.
Can be prevented. Also,
Form a groove for the flange at the end of the
Side of the control roller by the outer peripheral surface of the regulating roller on the side
To support the holding roller by supporting the edge
It is not necessary to separately provide such members. In addition, regulations
In the roller, adjust the radius of the part outside the groove to the part inside the groove.
Larger than the radius of the conveyor belt by the thickness of the conveyor belt.
The holding roller is supported on both sides by
It is possible to prevent tilting by the thickness of the bolt (claim 1).

At this time, by setting the height of the flange to be larger than 1/15 of the radius of the regulating roller, it is possible to more reliably prevent the flange of the conveying belt from riding on the end of the regulating roller. (Claim 2). Further, when the regulating roller is a driving roller, the flange and the end face of the driving roller rub against each other, so that there is a possibility that a fluctuation in load may cause jitter in belt running. By doing so, occurrence of such jitter can be avoided (claim 3).

Furthermore, by forming a tapered surface on the edge portion of the end portion of the regulating roller, the flanges of the conveyor belt, smoothly will be guided so as to abut against the regulating roller (claim 4) .

[0019]

[0020]

Embodiments of the present invention will be described below with reference to the drawings. First, referring to FIG. 2, an electrophotographic printer (color image forming apparatus) 1 including a paper transport unit 9A as a paper transport device of the present embodiment will be described. As shown in FIG. 2, the electrophotographic printer 1 according to the present embodiment is also configured substantially in the same manner as that shown in FIG. 9, and therefore, in FIG. The same reference numerals are given, and detailed description of the portions will be omitted.

The difference between the electrophotographic printer 1 according to the present embodiment and the printer shown in FIG. 9 is that the configuration of the paper transport section 9A described later with reference to FIGS. And a point where a separation claw 33 is provided. Similarly to the paper transport unit 9 shown in FIG. 9, the paper transport unit 9A according to the present embodiment uses the transport belt 17A and the driving roller 19, the driven roller 20A, and the tension applying roller (tensioner) 2A.
Endlessly wound around the outer circumferences of the motors 1 and 22, the motor is driven by transmitting the rotational driving force of a driving motor (not shown) from the driving roller 19, and is charged by a charger (not shown). The transfer paper (paper, sheet-like medium) 18 is electrostatically attracted to the outer surface (the surface facing the photoconductor 11) of the transport belt 17A, and the printing units 10Y, 10M, 10C,
They are transported in order to 10K.

However, in this embodiment, as shown in FIGS. 3 to 5, the transport belt 17A is
And a flange 17b protruding from the inner peripheral surface at both side edges of the resin sheet 17a. The driven roller 2
0A is substantially the same as the driven roller 20 shown in FIG. 9, but the driven roller 20A of this embodiment abuts the side end surface of the flange 17b while supporting the conveying belt 17A to change the position of the conveying belt 17A. It functions as a regulating roller that can be regulated.

Further, in the present embodiment, as shown in FIGS. 1, 2 and 6, the conveying belt 17A having a flange 17b protruded from the regulating roller 20A as described above.
Is provided with a pressing roller 30 which can press the side edge of the pressing roller 30A against the regulating roller 20A. The pressing roller 30 is rotatably supported by a tip end of a leaf spring 31 so as to press the side edge of the transport belt 17A toward the regulating roller 20A by the urging force of the leaf spring 31. . Accordingly, the pressing roller 30 presses the side edge portion of the transport belt 17A toward the regulating roller 20A while pressing the transport belt 17A.
It comes to accompany with the movement of. The base end of the leaf spring 31 is fixedly attached to a stay 32 fixed to the main body frame of the printer 1.

Here, a rubber material such as chloroprene rubber or urethane rubber is used for the flange 17b. Further, as a result of an experiment, it is desirable that the height H (see FIG. 5) of the flange 17b be set to be larger than one-fifteenth (H> r / 15) of the radius r (see FIG. 3) of the regulating roller 20A. .

The regulating roller has a diameter of 30 mm and a thickness of 0.1 mm.
For a 1mm resin belt, a rubber material with a hardness of 60
As a result of experiments on the case of forming a flange with a height of 0.8 mm and a flange with a height of 1.0 mm, the flange with a height of 0.8 mm did not have the effect of suppressing the skew of the resin belt and the flange portion was placed on the regulating roller. I got on,
With the flange having a height of 1.0 mm, the flange portion did not ride on the regulating roller, and the skew of the resin belt was reliably suppressed.

Further, in the regulating roller 20A of this embodiment, as shown in FIGS. 3 and 5, the edge portion 20a of the end contacting the flange 17b has a tapered surface (inclined surface) over the entire circumference of the regulating roller 20A. ) 20b are formed. With the above-described configuration, the regulating roller 20A, which is also a driven roller, contacts the side end surface of the flange 17b protruding from the inner peripheral surface of the transport belt 17A while supporting the transport belt 17A, so that the transport belt 17A The position is regulated, and the skew of the transport belt 17A can be reliably prevented. Therefore, in the paper transport section 9A of the present embodiment, the transfer paper 18 can be transported while being held at an accurate transport position.

At this time, by setting the height H of the flange 17b to be larger than 1/15 of the radius r of the regulating roller 20A, the flange 17b of the transport belt 17A rides on the end of the regulating roller 20A. And the peripheral speed of the surface of the conveyor belt 17A (resin belt 17a) can be reliably prevented from fluctuating in the width direction as the flange 17b rides on the conveyor belt 17b.
The skew of A can be prevented, and this contributes to the improvement of the accuracy of the transfer paper 18 in positioning.

When the driving roller 19 is used as a regulating roller, for example, the flange 1 of the transport belt 17A is used.
7b and the end face of the drive roller 19 rub against each other,
If the load fluctuates, there is a possibility that the running of the belt may become jitter. In an extreme case, the transport belt 1
If the flange 17b of 7A runs over, the peripheral speed of the transport belt 17A increases by the thickness of the flange 17b, and such an increase in speed also causes jitter. At this time,
Since a load change has also occurred, this also causes jitter.

On the other hand, by using a roller (for example, a driven roller 20A) other than the driving roller 19 as the regulating roller as in the present embodiment, the above-described generation of the jitter can be reliably avoided. It contributes to the improvement of the transfer positioning accuracy. The reason why the driven roller 20A is used as the regulating roller is that the driven roller 20A is the roller having the largest winding angle of the transport belt 17A among the rollers other than the drive roller 19, and the flange 17b of the transport belt 17A is used. The belt that receives the largest distance
This is because the regulating force can be most effectively applied to 7A.

Further, the edge portion 2 of the regulating roller 20A
By forming the tapered surface 20b on the taper 0a, the flange 17b of the transport belt 17A is guided so as to abut against the regulating roller 20A smoothly.
Rides on the end of the regulating roller 20A and moves the transport belt 1
It is possible to reliably prevent the peripheral speed of the surface of 7A from fluctuating in the width direction, thereby preventing the skew of the transport belt 17A, and contributing to the improvement of the accuracy of the transport paper 18 in positioning the transport.

Further, by pressing the side edge of the conveying belt 17A against the regulating roller 20A by the pressing roller 30, the flange 17b of the conveying belt 17A smoothly comes into contact with the regulating roller 20A. It is possible to forcibly suppress the flange 17b from riding on the end of the regulating roller 20A due to the skew force of the transport belt 17A. Therefore, the provision of the pressing roller 30 also prevents skew of the transport belt 17A,
As a result, the transfer paper 18 contributes to the improvement of the transfer positioning accuracy.

When the pressing roller 30 is provided, both ends of the pressing roller 30 are supported by a structure as shown in FIG. 7, for example, and the side edge of the transport belt 17A is pressed uniformly against the regulating roller 20B. It may be configured as follows. FIG. 7 shows a modification of the configuration in the case where the pressing roller 30 is provided in the present embodiment, and is a VI-VI of FIG.
FIG. 7 is a view corresponding to a cross section taken along an arrow (the position in FIG. 6).

Here, the regulating roller 20B functions as a driven roller similarly to the regulating roller 20A described above. However, at the end of the regulating roller 20B shown in FIG. A groove 20c for fitting is formed over the entire circumference. The inner end face (left end face in FIG. 7) of the groove 20c comes into contact with the side end face of the flange 17b protruding from the inner peripheral face of the transport belt 17A, like the end face of the regulating roller 20A described above. I have. An edge portion 20a of the inner end face of the groove 20c is also provided with a tapered surface 20 similar to the regulating roller 20A.
b is formed.

The regulating roller 20B is provided with a groove 20.
The radius R of the portion 20e outside the portion c is larger than the radius r of the portion 20d inside the groove portion 20c by the thickness t of the transport belt 17A (resin belt 17a) (R = r + t). In the present embodiment, the groove 20
The both ends of the pressing roller 30 are supported by the outer peripheral surfaces of the portions 20d and 20e on both sides of c.

As described above, both ends of the pressing roller 30 are supported, and the side edge of the transport belt 17A is uniformly pressed against the regulating roller 20B by the pressing roller 30, so that the structure shown in FIG. If the pressing roller 30 is not uniformly pressed against the regulating roller 20A, the pressing roller 30 is moved to the edge portion 20a of the regulating roller 20A.
There is a possibility that a load may be locally applied to the transport belt 17A at the edge portion 20a, and the transport belt 17A may be damaged.

On the other hand, with the structure shown in FIG. 7, the pressing roller 30 can uniformly press the side edge portion of the transport belt 17A against the regulating roller 20B. Since it is possible to prevent the control roller 20B from hitting against the edge portion 20a,
It is possible to reliably prevent the transport belt 17A from being damaged.

In the structure shown in FIG. 7, there is no need to provide special members for supporting both ends of the pressing roller 30, and the transport belt 17A can be moved without complicating the structure of the apparatus and increasing the cost. In addition to being stably pressed against the regulating roller 20B, the regulating roller 2
0B, the radius R of the outer part 20e
The radius r of the inner portion 20d of the roller 17] + [the thickness t of the resin belt 17a] can prevent the holding roller 30 from inclining by the thickness of the transport belt 17A in a state where both ends are supported. The roller 30 can be stably pressed against the regulating roller 20B.

Although FIGS. 1, 3, 6, and 7 show only the structure of one end of the regulating roller 20A or 20B, it goes without saying that the other end is similarly configured. . In the present embodiment, as shown in FIGS. 2 and 8, each of the printing units 10Y, 10M, 10
Transfer paper 18 on which the color image is transferred by C, 10K,
A separation claw 33 is provided at a portion to be transferred from the paper transport unit 9A to the fixing unit 16. The separation claw 33 is for forcibly separating the transfer paper 18 on the transport belt 17A from the transport belt 17A. As shown in FIG. 8, the transfer claw 33 transfers more than the printing units 10Y, 10M, 10C, and 10K. It is arranged so as to face the drive roller 19 on the downstream side in the paper advancing direction with the transport belt 17A interposed therebetween.

The contact point a between the separation claw 33 and the drive roller 19 (conveying belt 17A) is moved to the contact start position b between the conveying belt 17A (resin belt 17a) and the driving roller 19.
The separation claw 33 is disposed so as to be located in a plane connecting the paper entrance position (nip position of the fixing roller 16a) c of the fixing unit 16 or below the plane. In the method in which the transfer paper 18 is charged and electrostatically attracted to the transport belt 17A (resin belt 17a) and transported as in this embodiment, the transfer paper 18 after transfer is transferred to the transport belt 17A (resin belt 17a). From the paper, and there is a possibility that paper jam occurs.

In particular, the roller diameter (curvature) of the drive roller 19
Becomes larger, it is difficult for the leading end of the transfer paper 18 to float up from the transport belt 17A (resin belt 17a) at the curved portion of the drive roller 19 depending on only the rigidity of the transfer paper 18, and the possibility of paper jam increases. . Therefore, in this embodiment, by providing the above-described separation claw 33, the transfer paper 18 is transported by the separation claw 33 to the transport belt 1.
Since the sheet can be forcibly peeled off from the resin belt 7A (resin belt 17a) and sent to the fixing section 16, paper jam can be surely prevented.

As described above, according to the embodiment of the present invention, the skew of the conveyor belt 17A can be surely prevented, and the accuracy of positioning the transfer paper 18 for conveyance is greatly improved. Therefore, as in the present embodiment, the paper transport section 9A is transferred to the transfer paper 18A.
By applying the present invention to the electrophotographic printer 1 which requires accurate positioning, images of a plurality of colors can be accurately transferred to predetermined positions on the transfer paper 18, and a high-quality color image without color shift can be obtained. Can be formed.

In the above embodiment, the flange 1
7b and the pressing roller 30 are provided at both ends of the conveying belt 17A. For example, if the conveying belt 17A is configured to forcibly skew in only one direction, the flange 17b and the pressing roller 30 May be provided only at one end of the transport belt 17A, and the position regulation by the regulation rollers 20A and 20B may be performed only at the one end side.

With such a configuration, the same operation and effect as those of the above-described embodiment can be obtained. In addition, since the above-described structure may be provided only at one end of the regulating rollers 20A and 20B, the structure is simplified. And cost reduction can be achieved. Here, forcibly moving the conveyor belt 17A in only one direction can be easily realized by, for example, making a difference between the circumferential lengths of the conveyor belt 17A at both side edges, and inclining a driving roller or a driven roller. it can.

Further, in the above-described embodiment, the case where the paper transport device (paper transport unit 9A) of the present invention is applied to the electrophotographic printer 1 (color image forming device) has been described. However, the present invention is not limited to this, and by applying the present invention to a paper transport system that requires a high transport position accuracy, the same operational effects as those of the above-described embodiment can be obtained.

[0045]

As described above in detail, according to the paper transport apparatus of the present invention, the position of the transport belt is regulated by the contact of the regulating roller with the side end surface of the flange of the transport belt, and the transport belt is controlled. Skew can be reliably prevented, and paper (sheet-like medium) such as transfer paper can be transported while being held at an accurate transport position.

Therefore, when the paper transport apparatus of the present invention is applied to a color image forming apparatus or the like that requires accurate positioning of paper, multiple color images can be accurately transferred to predetermined positions on transfer paper. Thus, a high-quality color image without color shift can be formed. In addition, the pressing roller presses the side edge of the conveying belt against the regulating roller, so that the flange of the conveying belt smoothly contacts the regulating roller, and the flange is regulated by the skew force of the conveying belt. In this case, it is possible to forcibly suppress an attempt to ride on the end of the roller. In this case, too, it is possible to prevent the skew of the transport belt, and to improve the accuracy of the transport positioning of the paper (sheet-like medium) such as transfer paper. It contributes to improvement (claim 1).

At this time, by setting the height of the flange to be larger than one-fifteenth of the radius of the regulating roller, the flange of the conveying belt rides over the end of the regulating roller and the peripheral speed of the conveying belt surface is reduced. Fluctuation in the width direction can be reliably prevented, thereby contributing to prevention of skew of the transport belt and improvement of transport positioning accuracy of paper (sheet-like medium) such as transfer paper (claim 2).

Further, by using a regulating roller other than the driving roller, it is possible to reliably avoid the occurrence of jitter in belt running, thereby contributing to an improvement in the accuracy of positioning of the transfer of paper (sheet-like medium) such as transfer paper. Claim 3). Furthermore, the flange of the conveying belt is guided by the tapered surface of the regulating roller and smoothly contacts the regulating roller. In this case as well, the flange of the conveying belt rides over the end of the regulating roller and the periphery of the surface of the conveying belt. The speed can be reliably prevented from fluctuating in the width direction, preventing skew of the conveyor belt,
This contributes to an improvement in the accuracy of the transfer positioning of a sheet (a sheet-like medium) such as a transfer sheet.

The pressing roller uniformly presses the side edge of the conveying belt against the regulating roller, so that the pressing roller can be prevented from hitting against the edge of the regulating roller. It is possible to prevent an unnecessary load from being locally applied to damage the transport belt (claim 1 ). Also, by fitting the flange to the groove of the regulating roller and supporting both ends of the pressing roller by the outer peripheral surfaces of the regulating roller on both sides of the groove, there is no need to separately provide a member or the like for supporting the pressing roller, The transport belt can be stably pressed against the regulating roller without complicating the apparatus configuration and increasing the cost (claim 1 ).

Further, by setting the radii on both sides of the groove of the regulating roller in consideration of the thickness of the conveying belt, it is possible to prevent the holding roller from inclining by the thickness of the conveying belt while both ends are supported. The pressing roller can be stably pressed against the regulating roller.
1 ).

[Brief description of the drawings]

FIG. 1 is a side view of a main part showing a main part of a sheet conveying apparatus according to an embodiment of the present invention.

FIG. 2 is a side view schematically illustrating an example of an image forming apparatus to which the sheet conveying device according to the embodiment is applied.

FIG. 3 is a diagram showing a main part of the present embodiment with a part cut away.

FIG. 4 is a diagram illustrating a cross section in the width direction of the transport belt according to the embodiment.

FIG. 5 is an enlarged view of a portion V in FIG. 3;

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 1;

FIG. 7 is a diagram showing a modification of the configuration in the case where a pressing roller is provided in the present embodiment, corresponding to a cross section taken along line VI-VI of FIG. 1;

FIG. 8 is an enlarged view of a portion VIII in FIG. 2;

FIG. 9 is a side view schematically showing an internal configuration of a general image forming apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 electrophotographic printer (color image forming apparatus) 2 color print engine 3, 4 paper cassette 5 paper feeder 6 paper discharger 7 paper stacker 8 power supply / controller 9, 9A paper transporter (paper transporter) 10Y, 10M , 10C, 10K Printing unit 11 Photoconductor (transfer drum, latent image carrier) 12 Precharger 13 Optical unit 14 Developing unit 15 Transfer roller 16 Fixing unit 17, 17A Transport belt (electrostatic attraction belt, transfer belt) 17a Resin Belt 17b Flange 18 Transfer paper (paper, sheet-like medium) 19 Drive roller 20 Follower roller 20A, 20B Follower roller (restriction roller) 20a Edge portion 20b Tapered surface (slope) 20c Groove portion 20d Inner portion 20e Outer portion 21, 22 Tension application Roller (tensioner) 23 Transport roller 24, 24A Feed guide (transport path) 30 pressing roller 31 leaf spring 32 stay 33 separating claw

Continued on the front page (72) Inventor Yukihide Toda 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Mamoru Watanabe 1015 Uedanaka, Nakahara-ku, Nakazaki-ku Kawasaki City, Kanagawa Prefecture Fujitsu Limited (56) Reference References JP-A-59-168467 (JP, A) JP-A-4-98284 (JP, A) JP-A-55-17005 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B65H 5/02 G03G 15/00 518

Claims (4)

(57) [Claims] 1. A transport belt is supported by a plurality of rollers including a drive roller and a driven roller, and the transport belt is driven by the drive roller in a state where a sheet-like medium is held on the transport belt. In a paper transport apparatus for transporting a medium, a flange is provided on at least one of both side edges of the transport belt, and a position of the transport belt is brought into contact with a side end surface of the flange while supporting the transport belt. And a pressing roller capable of pressing the side edge of the conveyor belt provided with the flange against the restricting roller, and the flange is fitted to the end of the restricting roller. The groove
It is formed over the entire circumference of the regulating roller, and the regulating roller adjusts the radius of the portion outside the groove inside the groove.
Larger by the thickness of the conveyor belt than the radius of the side part
The pressing roller is formed with a side edge of the transport belt and the regulating roller.
On both sides of the groove so as to press evenly against
Both ends of the pressing roller are supported by the outer peripheral surface of the regulating roller.
A paper transport device, characterized by being held. 2. The method according to claim 1, wherein the height of the flange is set to be larger than one fifteenth of a radius of the regulating roller.
The sheet conveying device according to claim 1. 3. The sheet conveying device according to claim 1, wherein the regulating roller is a roller other than the driving roller. 4. A taper surface is formed over an entire periphery of the regulating roller at an edge portion of an end portion of the regulating roller which abuts on the flange. paper transport equipment described.