JP6911419B2 - Decaler device and image forming device using it - Google Patents

Description

The present invention relates to a decaler device that eliminates or alleviates curl (warp deformation) of a seat member. More specifically, the present invention relates to a decaler device that performs a curl elimination or mitigation process while passing through a sheet member to be conveyed. The present invention also covers an image forming apparatus using a decaler apparatus.

As an example of the conventional decaler device, the sheet transfer device described in Patent Document 1 can be mentioned. The sheet transfer device described in FIG. 1 of the same document passes the "sheet S" between the "conveyor belt 11" and the "pressing roll 16". The "conveying belt 11" is hung on two rollers, and the "pressing roll 16" is pressed against a middle portion between the two rollers. The "conveyor belt 11" is in a state of being slightly wound around the "pressing roll 16". In this sheet transfer device, the "sheet S" curled in the opposite direction to the winding is passed between the "conveyor belt 11" and the "pressing roll 16". As a result, the curl of the "seat S" is corrected.

Further, in this sheet conveying device, the pushing amount of the "pressing roll 16" into the "conveying belt 11" can be changed by the "cam 21". As a result, the amount of winding of the "conveying belt 11" around the "pressing roll 16" can be increased or decreased. In this way, in this sheet transfer device, the amount of curl correction of "Sheet S" can be adjusted.

Japanese Unexamined Patent Publication No. 2013-23292

However, the above-mentioned conventional technique has the following problems. Insufficient response to cases where curl correction is not required. That is, when the seat member is not curled, the pushing of the "pressing roll 16" into the "conveying belt 11" is released. Otherwise, the sheet transporting device will curl the paper. However, when this is done with the sheet transfer device of Patent Document 1, no nip pressure is applied between the "conveyor belt 11" and the "pressing roll 16". For this reason, paper transport is unstable and jams are likely to occur. In addition, there is a problem in the configuration of the surrounding paper guides.

The present invention has been made to solve the problems of the above-mentioned conventional techniques. That is, the problem is to provide a decaler device capable of adjusting the curl correction amount and stably transporting the sheet even when the correction amount is zero, and an image forming device using the decaler device.

The decaler device according to one aspect of the present invention is a transport member having a fixed position that contacts the first surface of the sheet member to be transported, and a transport member that contacts the second surface of the sheet member to be transported. A belt that circulates in a forward direction with respect to the transport direction of the seat member while being pressed against the belt, and a first tension member located upstream of the transport member in contact with the inner surface side of the belt to apply tension to the belt. A second tension member located on the downstream side of the transport member in the transport direction, a pressing member located on the inner surface side of the belt to prevent the belt from separating from the transport member, and a first tension member having a fixed position. A movement guide member provided for at least one of the second tension member and a movement guide member for guiding the movement of the first tension member or the second tension member in a direction for changing the amount of winding of the belt around the transport member, and a seat member. In addition to restricting the second surface of the A positive range is included, and the movable restricting member is arranged on the side of the first tension member and the second tension member that is moved by the movement guide member with respect to the transport member. At least of the first tension member and the second tension member so as to be separated from the transport member when the wrapping amount is increased and close to the transport member when the wrapping amount is decreased. It moves in conjunction with one movement .

In the decaler device of this aspect, the seat member is passed through the nip between the belt wound around the first tension member and the second tension member and the transport member. Here, at least one of the first tension member and the second tension member moves along the movement path guided by the movement guide member, so that the amount of wrapping of the belt around the transport member is changed. There is. By this movement, the amount of wrapping can be reduced to zero. However, even when the winding amount is set to zero, the pressing member prevents the belt from being separated from the conveying member. Therefore, the transfer of the sheet member is stable even when the winding amount is set to zero. When passing a sheet member curled in a direction in which the transport member side is convex, the curl is corrected by setting the winding amount to a positive state. When passing a sheet member that does not, the winding amount may be set to zero.

In the decaler device of the above aspect, it is desirable that the movement path by the movement guide member has a shape in which the tension applied to the belt is constant even if at least one of the first tension member and the second tension member is moved. If this is the case, jams and wrinkles are unlikely to occur because the paper passing resistance of the sheet member is constant regardless of the amount of wrapping of the belt around the transport member.

In the decaler device of the above aspect, or even in a state where at least one of the first tension member and the second tension member is moved to a position where the amount of winding of the belt around the transport member is maximized, the pressing member and the transport member It is desirable that the belt does not come into contact with any position other than the opposite position. If this is the case, it is easy to configure the device so that the tension of the belt is constant regardless of the amount of wrapping of the belt around the transport member.

In the above-mentioned decaler device, it is also preferable that the movement path by the movement guide member is provided only for the first tension member. Such a configuration is superior in terms of stability in the output direction of the seat member that has passed through the decaler device.

The decaler device of the above aspect has a curl amount detecting unit for detecting the curl amount of the sheet member, which is provided on the upstream side of the transport member in the transport direction, and when the detected curl amount is large, the wrapping amount. It is also desirable to have a wrap angle control unit that moves at least one of the first tension member and the second tension member so that the wrapping amount is reduced when the detected curl amount is small. By doing so, it is possible to perform appropriate curl correction for the degree of curl of each sheet member.

Alternatively, the decaler device of the above aspect has a movable restricting member that regulates the second surface of the seat member and moves along the transport direction, and the movable restricting member has a first tension member and a first tension member with respect to the transport member. It is located on the side of the two tension members that is moved by the movement guide member, so that it is separated from the transport member when the amount of wrapping is large and close to the transport member when the amount of wrapping is small. It is also desirable that the first tension member and the second tension member move in conjunction with the movement of at least one of them. If this is the case, interference between the belt and the movable restricting member can be prevented even when the winding amount is large, and the transportability of the seat member before and after the transport member is good even when the winding amount is small.

The image forming apparatus according to another aspect of the present invention is an apparatus having a sheet supply unit for supplying a sheet member and an image forming unit for forming an image on the sheet member supplied from the sheet supply unit. The decaler device of any of the above aspects is arranged on the transport path of the seat member supplied from the unit. As a result, the curl of the sheet member after image formation can be corrected in the image forming apparatus.

In the image forming apparatus of the above aspect, it is desirable that the decaler apparatus is arranged in a direction in which the belt is located on the concave side of the curl attached to the seat member in the image forming portion on the downstream side of the image forming portion. As a result, the curl generated in the sheet member due to the image formation can be corrected in the image forming apparatus.

In the image forming apparatus of the above aspect, a fixing device for fixing a toner image applied on the sheet member between the image forming portion and the decaler device by passing it between the heating member and the pressurizing member is further provided. It is desirable that the decaler device is arranged in the direction in which the belt is located on the side of the pressurizing member. In general, the fixing device has a strong tendency to curl the seat member. In addition, the sheet member tends to be curled so that the heating member side is convex. Therefore, with such a configuration, the curl generated on the sheet member by the fixing device can be corrected in the image forming device.

According to this configuration, a decaler device capable of adjusting the amount of curl correction and stably transporting a sheet even when the amount of correction is zero, and an image forming device using the decaler device are provided.

It is sectional drawing which shows the internal structure of the image forming apparatus which concerns on embodiment. It is a front view (the 1) which shows the structure of the decaler apparatus which concerns on embodiment. It is a front view (the 2) which shows the structure of the decaler apparatus which concerns on embodiment. It is a front view which shows the situation which the curl of a printing paper is corrected by a decaler device. It is a front view which shows the situation which the uncurled printing paper passes through a decaler device. It is a front view (the 1) which shows the relationship between the movement of a tension roller and a movement guide member. It is a front view (the 2) which shows the relationship between the movement of a tension roller and a movement guide member. FIG. 3 is a front view (No. 3) showing the relationship between the movement of the tension roller and the movement guide member. It is a front view (the 1) which shows the structure of the decaler apparatus in the state which the belt is wound around the transport roller. FIG. 2 is a front view (No. 2) showing the configuration of a decaler device in a state where a belt is wound around a transport roller. It is a front view (the 1) which shows the structural example which made the paper regulation member movable. It is a front view (the 2) which shows the structural example which made the paper regulation member movable. It is a front view which shows the configuration example which provided with the curl sensor. It is a front view which shows the configuration example which made only the tension roller on the upstream side movable. It is a front view which shows the configuration example which made the arrangement of a belt and a transport roller upside down.

Hereinafter, embodiments embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to the image forming apparatus shown in FIG. The image forming apparatus 1 shown in FIG. 1 is large and has a reading unit 2, a main body unit 3, and a paper feeding unit 4. The reading unit 2 is a part that reads a document and acquires image data. The main body 3 is a portion that forms an image based on image data. The paper feed unit 4 is a portion for storing the printing paper (sheet member) P used for image formation in the main body unit 3.

The main body 3 will be further described. The main body portion 3 is provided with an image forming portion 5 and a fixing portion 6. The image forming unit 5 is further provided with a photoconductor 7, a charger 8, an exposure device 9, a developer 10, a transfer belt 11, and a transfer roller 12. As a result, a toner image is formed on the printing paper P supplied from the paper feed unit 4. The fixing portion 6 has a pressure roller 13 and a heating roller 14. As a result, the toner image on the printing paper P is fixed.

The main body 3 is further provided with a transport path 15 for transporting the printing paper P. The transport path 15 is provided so as to transport the printing paper P supplied from the paper feed unit 4 via the transfer roller 12 of the image forming unit 5 and the fixing unit 6. A paper ejection roller 16 is provided at the end of the transport path 15. The fixing portion 6 described above is arranged in a portion of the transport path 15 on the downstream side of the image forming portion 5. The main body 3 is also provided with an inversion path 17 for turning over the image-formed printing paper P from the downstream side of the fixing portion 6 to the upstream side of the image forming portion 5.

In the image forming apparatus 1 of the present embodiment, the decaler apparatus 18 is provided on the downstream side of the fixing portion 6. The above-mentioned reversing path 17 is branched from the transport path 15 on the downstream side of the decaler device 18. The decaler device 18 is a device for correcting curls attached to the printing paper P that has come out of the fixing portion 6. Hereinafter, the decaler device 18 will be described in detail.

As shown in FIG. 2, the decaler device 18 includes a belt 19, a tension roller 20, and a tension roller 21. The belt 19 is hung on the tension roller 20 and the tension roller 21. Further, a certain amount of tension is applied to the belt 19. The decaler device 18 is further provided with a transport roller 22 and a pressing roller 23. The transport roller 22 is located outside the belt 19, while the pressing roller 23 is located inside the belt 19. There is only a gap about the thickness of the belt 19 between the transport roller 22 and the pressing roller 23. Therefore, the belt 19 is in contact with both the transport roller 22 and the pressing roller 23.

In the decaler device 18 having such a configuration, the printing paper P enters between the belt 19 and the transport roller 22 from the right in the drawing. That is, of the above-mentioned components of the decaler device 18, two parties, the belt 19 and the transport roller 22, come into contact with the printing paper P, one of which comes into contact with the first surface of the printing paper P, and the other of which comes into contact with the first surface of the printing paper P. Contact two sides. Therefore, when the printing paper P passes through the decaler device 18, the belt 19 circulates in the forward direction with respect to the transport direction of the printing paper P, and the transport roller 22 rotates. Of course, the tension roller 20, the tension roller 21, and the pressing roller 23 also rotate forward with respect to the circulation of the belt 19.

Here, of the above-mentioned components of the decaler device 18, the transfer roller 22 and the pressing roller 23 are fixed in position in the image forming apparatus 1. On the other hand, the positions of the tension roller 20 and the tension roller 21 in the image forming apparatus 1 are not fixed and are movable. Specifically, the tension roller 20 and the tension roller 21 can move in the vertical direction in FIG. FIG. 2 shows a state in which the tension roller 20 and the tension roller 21 are moved to a lower position within their movable range. On the contrary, FIG. 3 shows a state in which the vehicle is moved to an upward position.

Comparing the state of FIG. 2 with the state of FIG. 3, the winding angle of the belt 19 around the transport roller 22 is different due to the difference in the positions of the tension roller 20 and the tension roller 21. The wrapping angle is the range from the point A where the belt 19 starts to come into contact with the transport roller 22 to the point B where the belt 19 separates from the transport roller 22 from the center Q of the transport roller 22. It is the angle θ seen. On the other hand, the belt 19 in FIG. 3 does not wind around the transport roller 22, but conversely winds around the pressing roller 23. Therefore, the winding angle θ in the state of FIG. 3 is zero. Even in such a state, the belt 19 is not separated from the transport roller 22. This is because the pressing roller 23 prevents the belt 19 from being separated from the conveying roller 22, and the nip pressure is maintained. Therefore, even in the state of FIG. 3, the transfer of the printing paper P in the decaler device 18 is stable.

By setting the positions of the tension roller 20 and the tension roller 21 to be about halfway between FIGS. 2 and 3, the value of the winding angle θ can be set to a positive value although it is smaller than the angle in FIG. .. In both FIGS. 2 and 3, the decaler device 18 is drawn upside down from the one drawn in FIG.

FIG. 4 shows a situation in which the printing paper P passes through the decaler device 18 in the state of FIG. In FIG. 4, the section C in which the belt 19 is wound around the transport roller 22 has a shape that is convexly curved upward in the drawing. Therefore, when the printing paper P is curled in the direction of being convexly curved downward in the drawing, the curling of the printing paper P is corrected by passing the printing paper P through the decaler device 18 in the state of FIG. be able to. On the other hand, FIG. 5 shows a situation in which the printing paper P passes through the decaler device 18 in the state of FIG. In FIG. 5, the belt 19 is not wound around the transport roller 22. Therefore, it is suitable for passing uncurled printing paper P. This is because if the uncurled printing paper P is passed through the decaler device 18 in the state shown in FIG. 4, the printing paper P may be curled in the opposite direction.

Note that FIGS. 4 and 5 also show the paper regulating members 24, 25, 26, and 27 before and after the decaler device 18. Of these, the paper regulating member 24 on the upstream side of the decaler device 18 and on the side farther from the printing paper P when viewed from the belt 19 has a shape in which the printing paper P is moved toward the belt 19 as it approaches the transport roller 22. Is desirable. Further, the paper regulating member 27 on the downstream side of the decaler device 18 and closer to the printing paper P when viewed from the belt 19 has a shape in which the end portion on the transport roller 22 side is opened from the paper regulating member 26. desirable.

The decaler device 18 of this embodiment has movement guide members 28 and 29 as shown in FIG. The movement guide members 28 and 29 are members that guide the movement of the tension rollers 20 and 21 shown in FIGS. 2 and 3 (or FIGS. 4 and 5). That is, the movement guide members 28 and 29 are guide rails that define the positions of the shafts 30 and 31 of the tension rollers 20 and 21. The movement guide members 28 and 29 are fixedly arranged with respect to the image forming apparatus 1. FIG. 6 shows a state in which the belt 19 is wound around the transport roller 22, which is the same as that shown in FIG. 2 (or FIG. 4). In this state, the shafts 30 and 31 are located near the lower ends of the movement paths of the movement guide members 28 and 29.

FIG. 7 shows a state in which the tension rollers 20 and 21 are moved upward from the state of FIG. 6 to eliminate the wrapping of the belt 19 around the transport roller 22. In the state of FIG. 7, the belt 19 is not wound around the transport roller 22 or the pressing roller 23. In the state of FIG. 7, the shafts 30 and 31 are also located in the middle of the movement path of the movement guide members 28 and 29. FIG. 8 shows a state in which the tension rollers 20 and 21 are further moved upward from the state shown in FIG. 7 so that the belt 19 is wound around the pressing roller 23. The decaler device 18 in the state of FIG. 8 is in the same state as shown in FIG. 3 (or FIG. 5). In this state, the shafts 30 and 31 are located near the upper ends of the movement paths of the movement guide members 28 and 29.

Here, the shapes of the movement guide members 28 and 29 are defined so that the tension applied to the belt 19 is substantially constant regardless of the position of the movement guide members 28 and 29 in FIGS. 6 to 8. be. More specifically, when comparing FIGS. 6 to 8, the distance between the shaft 30 and the shaft 31 is the longest in the state of FIG. 7. The distance between the shaft 30 and the shaft 31 in the state of FIGS. 6 and 8 is slightly shorter than the distance in FIG. 7. This is a measure for making the circumference of the belt 19 constant in the figure.

That is, in the state of FIGS. 6 and 8, the range of the belt 19 including the portion sandwiched between the transport roller 22 and the pressing roller 23 is in a curved state. On the other hand, in the state of FIG. 7, the range of the belt 19 is linear. Therefore, if the distance between the shaft 30 and the shaft 31 is not set as described above, the belt 19 will be in an extended state in the states of FIGS. 6 and 8. In this case, the tension of the belt 19 is not constant, so the shapes of the movement guide members 28 and 29 are as described above. Therefore, in the decaler device 18 of the present embodiment, the paper passing resistance of the printing paper P is constant in any of the states of FIGS. 6 to 8.

It is also desirable that the decaler device 18 of the present embodiment be as shown in FIG. That is, FIG. 9 shows a state in which the amount of wrapping of the belt 19 around the transport roller 22 is maximized in the decaler device 18. In this state, the tension rollers 20 and 21 are located at the lower limit within the movable range. However, even in this state, the contact between the pressing roller 23 and the belt 19 is only one point where the conveying roller 22 and the pressing roller 23 face each other. That is, even in the arrow D in FIG. 9, the pressing roller 23 and the belt 19 are not in contact with each other. The effect of this is that the above-mentioned movement guide members 28 and 29 for keeping the tension of the belt 19 constant need to have a relatively simple shape.

On the other hand, as shown in FIG. 10, when the tension rollers 20 and 21 are located near the lower limit, the pressing roller 23 and the belt 19 may be in contact with each other at a portion E opposite to the transport roller 22. Conceivable. In this case, in order to keep the tension of the belt 19 constant, it is necessary to make the shapes of the movement guide members 28 and 29 slightly complicated. The reason is as described below.

That is, as shown in FIG. 10, when the tension rollers 20 and 21 are further lowered after the belt 19 and the pressing roller 23 come into contact with each other at the location E, the belt 19 is strongly stretched. This is because both the lower section and the upper section of the pressing roller 23 are curved. In order to keep the tension of the belt 19 constant even in such a situation, the movement guide members 28 and 29 need to have a shape strongly refracted inward in the left-right direction in the drawing near the lower end thereof.

This is not the case in the configuration example of FIG. 9, and the movement guide members 28 and 29 having a simple shape as shown in FIGS. 6 to 8 are sufficient. Therefore, it is easy to design the movement guide members 28 and 29. As a means for realizing the configuration example of FIG. 9, it is mentioned that a pressing roller 23 having a very large diameter is not used. Alternatively, the movable range of the tension rollers 20 and 21 should not be widened downward in the figure.

The configuration example shown in FIG. 10 is not necessarily inappropriate as an embodiment of the present invention. If the shapes of the movement guide members 28 and 29 take the above into consideration, they can be sufficiently used. This is because there is no difference between the surface speed of the pressing roller 23 and the traveling speed of the belt 19 even at the portion E in FIG.

Further, in the decaler device 18 of the present embodiment, the paper regulating members 25 and 27 among the paper regulating members 24 to 27 shown in FIGS. 4 and 5 can be made movable. This will be described with reference to FIGS. 11 and 12. The movable paper regulating members 25 and 27 are those on the belt 19 side of the passing printing paper P among the paper regulating members 24 to 27. FIG. 11 corresponds to FIG. 4, and shows a state in which the amount of winding of the belt 19 around the transport roller 22 is increased. On the other hand, FIG. 12 corresponds to FIG. 5 and shows a state in which the winding amount is set to zero.

Comparing FIGS. 11 and 12, not only the positions of the tension rollers 20 and 21 are different as described above, but also the positions of the paper regulating members 25 and 27 are different. In FIG. 11, as compared with the case of FIG. 12, the paper restricting members 25 and 27 are located at positions moved away from the transport roller 22 with respect to the left-right direction (the transport direction of the printing paper P) in the drawing. .. On the contrary, in FIG. 12, the paper regulating members 25 and 27 are located closer to the transport roller 22 than in the case of FIG.

As a result, the configuration examples of FIGS. 11 and 12 have the following advantages. First, in the state of FIG. 11, interference between the belt 19 and the paper regulating members 25 and 27 is prevented. This is because the paper regulating members 25 and 27 are retracted from the tension rollers 20 and 21. Nevertheless, in the state of FIG. 12, the outlets of the paper regulating members 24 and 25 on the upstream side and the entrances of the paper regulating members 26 and 27 on the downstream side are not opened excessively wide. Therefore, especially on the upstream side, the output direction of the printing paper P from the paper regulating members 24 and 25 to the transport roller 22 is relatively stable, and jam is unlikely to occur.

Further, when FIGS. 11 and 12 are compared with FIGS. 4 and 5, the arrangement of the paper regulating members 24 to 27 is different in the following points. That is, in the configuration examples of FIGS. 11 and 12, the distance between the paper regulation member 24 and the paper regulation member 25 is narrower than that of the configuration examples of FIGS. 4 and 5. The same applies to the distance between the paper regulating member 26 and the paper regulating member 27. This is made possible by making the paper regulating members 25 and 27 movable. This is because interference with the belt 19 is prevented and the stability of transporting the printing paper P is also improved. As a result, the transport path of the printing paper P can be made compact, which also contributes to the miniaturization of the image forming apparatus 1.

Further, as shown in FIG. 13, the decaler device 18 of the present embodiment may further include a curl sensor 32 and a control unit 33. In the configuration example of FIG. 13, the curl sensor 32 is arranged on the upstream side of the transport roller 22. The curl sensor 32 is a sensor that detects the distance between the printing paper P and the printing paper P by irradiating the printing paper P traveling between the paper restricting members 24 and 25 with light or ultrasonic waves. The control unit 33 controls to operate the positions of the tension rollers 20 and 21 in response to the detection result of the curl sensor 32. As a result, the amount of wrapping of the belt 19 around the transport roller 22 is controlled according to the detection result of the curl sensor 32. The control unit 33 may also control the entire image forming apparatus 1.

In the configuration example of FIG. 13, the curl state of the printing paper P at that time is detected based on the tendency of the detection result of the curl sensor 32 to change during the period when one printing paper P passes through the location of the curl sensor 32. be able to. That is, if the tendency of "near-> far-> near" is shown within the passing period of one printing paper P, it means that the printing paper P at that time is curled downward. In that case, the positions of the tension rollers 20 and 21 are operated by the control of the control unit 33, and the state shown in FIG. 4 is obtained. Therefore, the printing paper P is discharged after the curl is corrected. On the other hand, if the incoming printing paper P is not curled downward, the state shown in FIG. 5 is obtained. Therefore, the printing paper P is discharged without correcting the curl.

Further, in the configuration example of FIG. 13, when the printing paper P is curled downward, control can be performed according to the degree of curling. This is because when the difference between "near" and "far" in the tendency of "near → far → near" is large, the degree of curl is strong. The position of the tension rollers 20 and 21 is controlled so that the winding angle θ in the state of FIG. 4 increases as the degree of the detected curl becomes stronger. If the degree of curl detected is small, the winding angle θ is reduced. As described above, in the configuration example of FIG. 13, appropriate curl correction can be performed on each printing sheet P. This is useful, for example, when the printing paper P after printing on the first side and the printing paper P after printing on the second side alternate in the decaler device 18 in double-sided printing.

Further, even when the paper regulating members 25 and 27 shown in FIGS. 11 and 12 are movable, the curl sensor 32 and the control unit 33 can be provided. In that case, the positions of the paper regulating members 25 and 27 are also under the control of the control unit 33. The curl sensor 32 may be arranged not on the side of the paper regulating member 25 but on the side of the paper regulating member 24. In the case of that arrangement, when the detection result is “far → near → far”, it is determined that the printing paper P is curled downward.

In the explanation so far, both the tension roller 20 and the tension roller 21 are movable in order to make the winding angle θ variable. But this is not a requirement. Only one of the tension rollers 20 and 21 may be movable and the other may be fixed. FIG. 14 shows a configuration example in which the tension roller 20 on the upstream side is movable and the tension roller 21 on the downstream side is fixed. When the tension roller 21 on the downstream side is fixed in this way, there is an advantage that the output direction of the printing paper P to the outlet side (the side of the paper regulating members 26 and 27) is stable regardless of the winding angle θ. ..

In the configuration example of FIG. 14, the paper regulating member 25 can be made movable as described with reference to FIGS. 11 and 12. However, there is no particular meaning that the paper regulating member 27 is movable. Further, of course, the curl sensor 32 shown in FIG. 13 can be provided in the configuration example of FIG. Further, on the contrary to FIG. 14, a configuration example in which the tension roller 20 on the upstream side is fixed and the tension roller 21 on the downstream side is movable can also be omitted.

Further, in the decaler device 18 described in FIGS. 2 to 14 so far, the transport roller 22 is located on the lower side of the printing paper P, and the tension rollers 20, 21 and the belt 19 are located on the upper side. It was a thing. This is upside down from the decaler device 18 in the image forming device 1 shown in FIG.

In FIG. 1, the fixing portion 6 is arranged such that the pressure roller 13 is on the bottom and the heating roller 14 is on the top. Generally, in the image forming apparatus 1 using toner as a coloring material, the fixing portion 6 has the greatest influence on the curl of the printing paper P, and the heating roller 14 side of the pressurizing roller 13 and the heating roller 14 is convex. The printing paper P tends to curl as described above. Therefore, as shown in FIG. 15, FIG. 1 shows that the decaler device 18 is arranged according to the vertical relationship between the pressure roller 13 and the heating roller 14. Therefore, in the decaler device 18 of FIGS. 1 and 15, the transport roller 22 is located on the upper side (heating roller 14 side), and the tension rollers 20, 21 and the belt 19 are located on the lower side (pressurizing roller 13 side). There is.

That is, the decaler device 18 of FIGS. 2 to 14 is arranged so as to be aligned with the case where the fixing portion 6 is arranged upside down from that of FIG. Further, in the case where the two rollers of the fixing portion 6 are both heating rollers, the curl tendency of the printing paper P may be determined by the configuration further upstream than the fixing portion 6. In that case, the vertical orientation of the decaler device 18 may be determined according to the curl tendency.

As described in detail above, according to the present embodiment, in a configuration in which the printing paper P is conveyed by passing the printing paper P through the nip portion between the conveying roller 22 and the belt 19, the belt 19 is transferred to the conveying roller 22. The amount of wrapping is variable. As a result, it is possible to switch between a state in which the curl is corrected and a state in which the curl is not corrected according to the state of the curl attached to the printing paper P passing through the decaler device 18. In addition, the degree of correction in the state where the curl is corrected can be adjusted. Here, the belt 19 is sandwiched between the transport roller 22 and the pressing roller 23. Therefore, the transfer of the printing paper P is stable even when the curl is not corrected. In this way, a decaler device 18 in which the transfer of the printing paper P is stable regardless of the degree of curl correction and a decaler device 18 using the decaler device 18 are realized.

It should be noted that the present embodiment is merely an example and does not limit the present invention in any way. Therefore, as a matter of course, the present invention can be improved and modified in various ways without departing from the gist thereof. For example, in the above embodiment, the present invention is applied to an image forming apparatus 1 using an image forming unit 5 that forms an image with toner. However, the present invention is not limited to this, and the present invention can be applied to an image forming apparatus of a type using a coloring material other than toner. In that case, of course, the fixing portion 6 does not exist, so the decaler device 18 is arranged at a position where curl is likely to occur in consideration of the direction of curl that is likely to occur, according to the specific configuration of the image forming apparatus. Become.

Even in the case of an image forming apparatus that forms an image with toner, the position where the decaler apparatus 18 can be arranged is not limited to the position on the downstream side of the fixing portion 6. Even in other places, if there is a position where curl is likely to occur, the decaler device 18 can be arranged at a position immediately downstream of the position. Further, not only the printing paper P but also the original read by the reading unit 2 can be curled by the decaler device 18. Further, the image forming apparatus to which the present invention is applied may be a printer type having no reading unit 2 or a non-color monochrome image forming apparatus. It may be capable of sending and receiving print jobs to and from other devices. Further, the transport roller 22, the pressing roller 23, and the tension rollers 20 and 21 do not necessarily have to be rotating members as long as they are slippery.

1 Image forming device 3 Main body part 5 Image forming part 6 Fixing part 13 Pressurizing roller 14 Heating roller 15 Conveyance path 18 Decaler device 19 Belt 20 Tension roller 21 Tension roller 22 Conveying roller 23 Pressing roller 25 Paper regulating member 27 Paper regulating member 28 Movement guide member 29 Movement guide member 32 Curl sensor 33 Control unit

Claims (8)

A transport member with a fixed position that contacts the first surface of the sheet member to be transported,
A belt that contacts the second surface of the sheet member to be transported and presses the sheet member against the transfer member while circulating in a forward direction with respect to the transfer direction of the sheet member.
A first tension member located on the upstream side of the transport member in the transport direction, which contacts the inner surface side of the belt and applies tension to the belt, and is located on the downstream side of the transport member in the transport direction. The second tension member and
A pressing member with a fixed position, which is located on the inner surface side of the belt and prevents the belt from separating from the conveying member.
Movement of the first tension member or the second tension member in a direction provided for at least one of the first tension member and the second tension member and changing the amount of winding of the belt around the transport member. a moving guide member for guiding the,
It has a movable restricting member that regulates the second surface of the seat member and moves along the transport direction.
The movement path guided by the movement guide member includes a range in which the wrapping amount is zero and a range in which the wrapping amount is positive .
The movable restricting member is
It is arranged on the side of the first tension member and the second tension member that is moved by the movement guide member with respect to the transport member.
At least one of the first tension member and the second tension member is moved so as to be separated from the transport member when the wrapping amount is increased and close to the transport member when the wrapping amount is decreased. A decaler device characterized in that it moves in conjunction with. The decaler device according to claim 1.
The movement path by the movement guide member is a decaler device having a shape in which the tension applied to the belt is constant even if at least one of the first tension member and the second tension member is moved. .. The decaler device according to any one of claims 1 to 2.
The pressing member faces the transport member even when at least one of the first tension member and the second tension member is moved to a position where the amount of winding of the belt around the transport member is maximized. A decaler device characterized in that it does not come into contact with the belt at a position other than the position. The decaler device according to any one of claims 1 to 3.
A decaler device characterized in that a movement path by the movement guide member is provided only for the first tension member. The decaler device according to any one of claims 1 to 4.
It has a curl amount detecting unit for detecting the curl amount of the sheet member, which is provided on the upstream side of the transport member in the transport direction.
At least one of the first tension member and the second tension member so as to increase the wrapping amount when the detected curl amount is large and decrease the wrapping amount when the detected curl amount is small. A decaler device characterized by having a wrapping angle control unit for moving the wrapping angle. An image forming apparatus having a sheet supply unit for supplying a sheet member and an image forming unit for forming an image on the sheet member supplied from the sheet supply unit.
An image forming apparatus according to any one of claims 1 to 5 , wherein the decaler device according to any one of claims 1 to 5 is arranged on a transport path of a sheet member supplied from the sheet supply unit. The image forming apparatus according to claim 6, wherein the decaler apparatus is
Downstream from the image forming part,
An image forming apparatus, characterized in that the belt is arranged in a direction in which the belt is located on the concave side of a curl attached to the sheet member in the image forming portion. The image forming apparatus according to claim 7.
A fixing device is provided between the image forming unit and the decaler device, in which a toner image applied on a sheet member is passed between a heating member and a pressure member to be fixed.
The decaler device is an image forming device characterized in that the belt is arranged in a direction in which the belt is located on the side of the pressurizing member.

Images