JP2011145365A - Cooling device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device capable of decreasing a temperature difference in a width direction of a sheet-like member, and an image forming apparatus including the cooling device. <P>SOLUTION: The cooling device includes a cooling roller composed of a hollow tubular member, and a cooling medium conveying means for conveying a cooling medium into the tubular member, and cools the sheet-like member by bringing the sheet-like member into contact with the cooling roller, wherein at least two cooling rollers having shorter width in a shaft direction than the maximum width of the sheet-like member that can be used in the image forming apparatus are disposed to occupy the maximum width. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cooling device used in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, and an image forming apparatus provided with the cooling device.

  2. Description of the Related Art As an image forming apparatus, an apparatus that forms a toner image on a sheet-like sheet using electrophotographic technology and melts and fuses the toner by passing through a thermal fixing device is known. In general, the temperature of the heat fixing device varies depending on the type of toner and paper, the paper conveyance speed, and the like, but is set and controlled at a temperature of about 180 ° C. to 200 ° C. to fuse the toner instantaneously. The surface temperature of the paper immediately after passing through the heat fixing device is a high temperature of about 100 ° C. to 130 ° C., for example, although it depends on the heat capacity (specific heat, density, etc.) of the paper. In addition, the toner immediately after passing through the heat fixing device is not completely hardened and remains slightly soft and remains in a sticky state for a while. Therefore, when the image output operation is repeated continuously and the paper after passing through the heat fixing device is stacked in the paper discharge container, if the toner on the paper cannot be sufficiently cured and is in a soft state, the toner on the paper A so-called blocking phenomenon that sticks to another sheet may be caused and image quality may be significantly lowered.

  In the image forming apparatus described in Patent Document 1, a cooling device including a cooling roller that cools while contacting a sheet and conveying the sheet is provided on the downstream side in the sheet conveying direction from the thermal fixing device. The paper after passing through the heat fixing device is cooled by the cooling roller of the cooling device, so that the toner on the paper is cooled and hardened, and the occurrence of the blocking phenomenon can be suppressed. In addition, the cooling roller has a tubular structure, and the cooling liquid flows into the cooling roller from one end side to the other end side in the longitudinal direction of the cooling roller. To be cooled.

  However, since the coolant flows through the cooling roller in one direction from one end side to the other end side in the longitudinal direction of the cooling roller, the temperature of the coolant is lowest on the one end side, and on the other end side. The temperature of the coolant increases due to the heat absorbed by the cooling roller from the paper. Therefore, a difference in cooling efficiency with respect to the sheet occurs in the longitudinal direction of the cooling roller due to a temperature difference in the longitudinal direction of the cooling roller, and the sheet is cooled with a temperature gradient in the longitudinal direction of the cooling roller. A temperature difference occurs in the paper in the width direction. When a temperature difference occurs in the width direction of the sheet, for example, the sheet curls and the sheet is easily jammed in the sheet conveyance path from the cooling device to the sheet discharge storage unit.

  SUMMARY An advantage of some aspects of the invention is that it provides a cooling device capable of reducing a temperature difference in the width direction of a sheet-like member and an image forming apparatus including the cooling device. is there.

In order to achieve the above object, the invention of claim 1 comprises a cooling roller made of a hollow tubular member, and a cooling medium conveying means for conveying the cooling medium into the tubular member, and a sheet is provided on the cooling roller. In the cooling device that cools the sheet-like member by contacting the sheet-like member, the cooling roller having an axial width shorter than the maximum width of the sheet-like member that can be used in the image forming apparatus is at least so as to occupy the maximum width. Two are arranged.
According to a second aspect of the present invention, in the cooling device according to the first aspect, a cooling medium is supplied into the tubular member at the end portion on the central portion side of the maximum width in the axial direction of the cooling roller. A supply port is provided, and a discharge port through which the cooling medium is discharged from the tubular member is provided on the end side of the maximum width in the axial direction of the cooling roller.
According to a third aspect of the present invention, in the cooling device according to the first or second aspect, the tubular member can be rotated at least at the end portion on the central portion side of the maximum width in the axial direction of the cooling roller. And a rotary pipe joint means for connecting the tubular member and the cooling medium supply / conveyance means, and both ends of the tubular member in the axial direction of the cooling roller are rotatably fitted to the apparatus main body or the structure of the image forming apparatus. It is characterized by being supported by a joint relationship.
According to a fourth aspect of the present invention, in the cooling device of the first, second, or third aspect, a core member having a smaller diameter than the outer tube is included in the hollow interior of the outer tube, which is the tubular member, and the cooling roller is A flow path through which a cooling medium flows is formed in a gap formed by the inner peripheral surface of the outer tube and the outer peripheral surface of the core member.
According to a fifth aspect of the present invention, in the cooling device of the first, second, or third aspect, an inner tube having a narrower tube structure than the outer tube is included in the hollow interior of the outer tube that is the tubular member, and the cooling roller is The double pipe structure has an outer flow path through which a cooling medium flows between the outer pipe and the inner pipe, and an inner flow path through which the cooling medium flows through the inner pipe.
Further, the invention of claim 6 is the cooling device of claim 1, 2, 3, 4 or 5, wherein the outer tube and the shaft portion are integrally structured on the end portion side of the maximum width of the cooling roller, The shaft portion is rotatably supported by a bearing, and the discharge port at the outer end of the apparatus is configured such that the cooling medium is discharged into the reserve tank. The invention of claim 7 is the cooling device of claim 1, 2, 3, 4, 5 or 6, wherein the first cooling roller and the second cooling roller are perpendicular to the conveying direction of the sheet-like member. In the direction perpendicular to the conveyance direction of the sheet medium, the central portion in the width direction of the sheet medium to be conveyed is connected to the flow path of the first cooling roller and the second in the sheet passing width. At least one of the first cooling roller and the second cooling roller is moved in the orthogonal direction so as to pass through a substantially central position in a range where the flow path of the cooling roller overlaps. Is.
The invention according to claim 8 is the cooling device according to claim 1, wherein a width in a direction perpendicular to the conveying direction of the sheet-like member is the first cooling roller. And the second cooling roller, the width of the sheet-like member in the cooling roller axial direction is wider than the width of the sheet-like member. The sheet-like member is conveyed to the second cooling roller, and the cooling medium is allowed to flow only to the cooling roller on the side where the sheet-like member is conveyed.
The invention according to claim 9 is the cooling device according to claim 1, 2, 3, 4, 5, 6, 7 or 8, and the flow rate of the cooling medium passed through the first cooling roller and the second cooling roller. And a cooling efficiency of the sheet-like member by the first cooling roller and a cooling efficiency of the sheet-like member by the second cooling roller are the same. As described above, the flow rate of the cooling medium flowing through the first cooling roller and the flow rate of the cooling medium flowing through the second cooling roller are adjusted by the flow rate adjusting means.
According to a tenth aspect of the present invention, there is provided a toner image forming means for forming a toner image on a sheet-like member, and a heat fixing means for fixing the toner image formed on the sheet-like member to the sheet-like member by at least heat. And a cooling unit that cools the sheet-like member on which the toner image has been fixed by the thermal fixing unit, wherein the cooling unit is the claim 1, 2, 3, 4, 5, 6, 7, 8 or 9 cooling devices are used.

  In the present invention, the sheet-shaped member is formed by at least two cooling rollers disposed so as to occupy the maximum width of the sheet-shaped member usable in the image forming apparatus and having an axial width shorter than the maximum width of the sheet-shaped member. The cooling range in the width direction of the member is divided. Thereby, the amount of heat received by the cooling medium flowing in each cooling roller is less than the amount of heat received by the cooling medium flowing from one end side to the other end side in one cooling roller at the maximum width of the sheet-like member. Therefore, the temperature rise of the cooling medium flowing through each cooling roller can be suppressed. Therefore, the temperature difference in the axial direction of each cooling roller can be reduced as compared with the configuration in which the cooling medium flows from one end side to the other end side in one cooling roller with the maximum width of the sheet-like member. Thus, by reducing the temperature difference in the axial direction of each cooling roller, the difference in cooling efficiency of the sheet-like member by each cooling roller in the width direction of the sheet-like member is reduced, and the cooling roller is correspondingly cooled. The temperature difference in the width direction of the sheet-like member can be reduced.

  As mentioned above, according to this invention, there exists the outstanding effect that the temperature difference of the width direction of a sheet-like member can be reduced.

2 is a schematic diagram of a cooling roller and a cooling device according to Configuration Example 1. FIG. Schematic of an example of a cooling device provided with a cooling roller. The schematic diagram of an example of the cooling roller which attached the single type rotary joint. The schematic diagram of an example of the cooling roller which attached the double type | mold rotary joint. FIG. 9 is a schematic diagram of a cooling roller according to Configuration Example 2. FIG. 10 is a schematic diagram of a cooling roller according to Configuration Example 3. FIG. 6 is a schematic diagram of a cooling roller and a cooling device according to Configuration Example 4. The whole unit block diagram of a cooling device. Schematic of a cooling roller. The schematic diagram of the bracket upper board part of a cooling device. 10 is a schematic diagram of a cooling roller and a cooling device according to Configuration Example 5. FIG. FIG. 10 is a schematic diagram of a cooling roller and a cooling device according to Configuration Example 6. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment.

  The cooling roller and the cooling device of the present invention will be described using an image forming apparatus in which toner on a recording sheet is fixed by a thermal fixing unit. However, the cooling roller and the cooling device of the present invention are not limited to this, and can be applied to any device that requires cooling of the sheet medium.

  The cooling roller as a cooling means has a tubular structure, and the surface of the cooling roller is cooled by flowing and circulating a cooling liquid therein. A cooling device having this cooling roller is disposed in the paper conveyance path immediately after the heat fixing means, and the paper is conveyed by the cooling roller and brought into contact with it to remove heat from the paper and cool it.

  FIG. 2 is a schematic diagram of an example of a cooling device 100 including a cooling roller 10a and a cooling roller 10b that also serve to convey a sheet. The cooling device 100 is provided with rollers 2 and 3 arranged at intervals in the conveyance direction (left-right direction) of the paper P, and the conveyance belt 4 for paper conveyance is stretched. Then, with the roller 2 on the downstream side in the paper transport direction as a driving roller (connected to a drive source not shown), the transport belt 4 is rotated counterclockwise to transport the paper from the right side to the left side in the figure.

  A heat fixing unit 7 is disposed upstream of the cooling device 100 in the paper conveyance direction, a paper discharge accommodating portion 8 is provided downstream of the cooling device 100 in the paper conveyance direction, and heat fixing is performed above the rollers 3. An upper guide 5 for guiding the paper P conveyed from the means 7 is provided. In addition, a cooling roller 10a and a cooling roller 10b are pressed against each other at an intermediate position between the roller 2 and the roller 3 so as to bite into the conveying belt 4, and the cooling roller 10a and the cooling roller 10b are in contact with the conveying belt 4. It is designed to rotate with the use of conveying force. Reference numeral 6 in the figure denotes a bracket that constitutes the main body of the cooling device 100, and is a member that supports component parts such as the roller 2, the roller 3, the cooling roller 10 a, the cooling roller 10 b, and the upper guide 5 in a fixed or rotatable manner. is there. The cooling device 100 is unitized by the bracket 6 and incorporated into the image forming apparatus main body.

  The paper P heated to a high temperature by the heat fixing unit 7 passes through the cooling device 100 before being discharged to the paper discharge storage unit 8. Specifically, the sheet P that has reached a high temperature through the heat fixing unit 7 enters between the upper guide 5 and the roller 3 of the cooling device 100 and then a nip formed by the cooling roller 10 b and the conveying belt 4. The sheet passes through the area, the nip area formed by the cooling roller 10 a and the conveyor belt 4, and is discharged to the sheet discharge container 8. The inside of the cooling roller 10a and the cooling roller 10b has a hollow tube structure, and the cooling liquid sufficiently cooled outside is supplied into the cooling roller 10a and the cooling roller 10b, and the inside of the cooling roller 10a and the cooling roller After circulating through 10b, the cooling liquid is discharged from the cooling roller 10a or the cooling roller 10b. The sheet P is in close contact with and in contact with the cooling roller 10 in a nip region formed by contact between the cooling roller 10a and the conveyance belt 4 or in a nip region formed by contact between the cooling roller 10b and the conveyance belt 4. At this time, the heat of the paper P is absorbed by the cooling roller 10a and the cooling roller 10b, and the paper P is sufficiently cooled. For example, the paper P can be cooled to about 50 to 60 ° C. by passing the paper P through the cooling device 100 when the surface temperature of the paper P immediately after passing through the heat fixing unit 7 is about 100 ° C.

  As will be described later with reference to FIG. 12, the cooling roller 10 a and the cooling roller 10 b are connected to a cooling liquid circulation device 500 such as a radiator 54 equipped with a tank 51, a pump 52, and a cooling fan 53 via a rotary joint 11 and a liquid supply tube. The cooling roller 10a and the cooling roller 10b are cooled by flowing the cooling liquid into the cooling roller 10a and the cooling roller 10b. Then, the paper P heated to the high temperature by the heat fixing unit 7 is conveyed to the cooled cooling roller 10a or cooling roller 10b, and the paper P is cooled by the cooling roller 10a or the cooling roller 10b.

  Here, there is a rotary joint as a commonly used rotary pipe joint means. There are two types of rotary joints, the single type and the double type. In the single type, the coolant is supplied only from one direction, and the discharge is performed from the opposite side. The dual type supplies and discharges the coolant from the same direction. An example of the cooling roller 10 to which a single rotary joint is attached is shown in FIG.

  3 is supplied from the supply port 19 of the rotary joint 20 as a rotary pipe joint means to the cooling roller 10 shown in FIG. , And is discharged from the discharge port 13 of the rotary joint 21 on the opposite side of the rotary joint 29 in the cooling roller axial direction. At this time, the outer tube 14 is cooled by the coolant 1 flowing through the flow path 16.

  Here, at the position where the coolant flows into the flow path 16 from the supply port 19 (the end of the flow path 16 on the cooling roller axial direction rotary joint 20 side), the temperature of the coolant is low, but is shown in FIG. Since the sheet P heated through the heat fixing unit 7 passes while contacting the surface of the cooling roller 10, the temperature of the coolant flowing through the flow path 16 is changed from the rotary joint 20 side to the rotary joint 21 side in the cooling roller axial direction. As you go up, it rises. Therefore, the surface temperature of the outer tube 14 of the cooling roller 10 is lowest on the rotary joint 20 side in the cooling roller axial direction and highest on the rotary joint 21 side in the cooling roller axial direction.

  Therefore, the cooling efficiency of the sheet P by the cooling roller 10 is highest on the rotary joint 20 side in the cooling roller axial direction of the outer tube 14 and lowest on the rotary joint 21 side in the cooling roller axial direction of the outer tube 14. There is a temperature gradient across the entire width of the cooling roller in the axial direction, and the temperature difference and the cooling efficiency difference also increase.

  Next, an example of the cooling roller 10 to which the rotary joint 11 which is a commonly used type of rotary pipe joint means is attached will be described with reference to a schematic sectional view shown in FIG.

  As shown in FIG. 4, the cooling roller 10 has a hollow tube structure including an outer tube 14 and an inner tube 15, and the outer tube 14 rotates to contact and transport the paper P.

  Both ends of the outer tube 14 are constituted by a flange 10c with a shaft and a flange 10d in which a bearing 10g is fitted and press-fitted, and an O-ring 10e for preventing leakage is inserted into both flanges, and each flange is removed by a screw 10f. It is attached to the tube 14. At this time, both flanges are inserted and attached to the outer tube 14 in a fitting relationship, and the coaxiality with the outer tube 14 is obtained. The cooling roller 10 is rotatably supported at both ends with respect to the bracket 6 of the cooling device 100 using the shaft of the flange 10c and the bearing 10g of the flange 10d.

  Further, the flange 10d is formed with a coupling portion including a parallel screw portion 10h and a fitting portion 10i. The flange 10d has a parallel screw portion 11b and a fitting portion 11c formed so as to face the coupling portion. Is attached. The parallel threaded portions 10h and 11b of the flange 10d and the rotor 11a are threaded in a direction that can be tightened with respect to the rotation direction of the outer tube 14 (paper P conveyance direction).

  The rotor 11a is a component of the rotary joint 11, and is supported by the casing 11e of the rotary joint 11 so as to be rotatable in a fitting relationship with two bearings 11d provided at intervals.

  Since the attachment of the rotor 11a and the flange 10d is the insertion and attachment by the fitting relationship as described above, the coaxiality between the rotor 11a and the flange 10d is obtained. From this, the outer tube 14 is in a state in which the shaft is aligned with the casing 11e of the rotary joint 11 via the rotor 11a and the flange 22d, which are attached in a fitting relationship, and high-accuracy rotation is achieved. It can be done. Note that an O-ring 11g that prevents leakage of coolant from the gap with the flange 10d is inserted into the rotor 11a.

  The cooling roller 10 may have a configuration in which the outer tube 14 rotates and the inner tube 15 is fixed (non-rotated), or a configuration in which the outer tube 14 rotates and the inner tube 15 rotates together with the outer tube 14. Here, the cooling roller 10 having a configuration in which the outer tube 14 is rotated and the inner tube 15 is fixed (non-rotated) will be described.

  As shown in FIG. 4, one end of the inner tube 15 on the rotary joint 11 side is fixed and supported by the rotary joint 11 so as not to rotate, and the other end is rotatably supported by the flange 10 c of the outer tube 14. The inner pipe 15 is attached to the rotary joint 11 by press-fitting one end side of the inner pipe 15 into the flange 11f attached to the casing 11e so that the inner pipe 15 is fixedly supported by the flange 11f. Moreover, since the casing 11e, the flange 11f, and the inner tube 15 are inserted and attached in a fitting relationship with each other, the coaxiality of the inner tube 15 is extended with respect to the casing 11e. In addition, the flange 11f inserts an O-ring 11i for preventing leakage, and is attached to the casing 11e with a screw 11h. The inner tube 15 is rotatably supported by the other end of the inner tube 15 being attached to the flange 10c via a bearing 10j. Since the flange 10c, the bearing 10j, and the inner tube 15 are inserted and attached in a fitting relationship with each other, the coaxiality of the inner tube 15 with respect to the flange 10c is also provided.

  With the above configuration, the coaxiality between the outer tube 14 and the inner tube 15 is provided on one end side of the cooling roller 10 with reference to the casing 11e of the rotary joint 11, and the outer tube is relative to the casing 11e of the rotary joint 11. Reference numeral 14 is rotatably supported, and the inner tube 15 is fixedly supported so as not to rotate with respect to the casing 11e. The other end side of the cooling roller 10 is supported so that the outer tube 14 and the inner tube 15 are coaxial with each other via the flange 10 c and the inner tube 15 is rotatable with respect to the outer tube 14. .

  An opening hole 10k is formed in the outer peripheral wall of the inner tube 15 on the flange 10c side, and a cross-sectional hole 10m is formed on the end surface of the inner tube 15 on the rotary joint 11 side. The coolant supplied from the supply port 19 of the rotary joint 11 through the sectional hole 10m of the inner tube 15 into the inner tube 15 flows into the gap between the outer tube 14 and the inner tube 15 through the opening hole 10k. Then, it passes through the rotary joint 11 and is discharged from the discharge port 13 to the outside.

  As indicated by the arrows in the flow path of the coolant 1, the coolant 1 supplied into the rotary joint 11 first flows in the inner tube 15 in the axial direction and reaches the end on the axial flange side of the inner tube 15. In FIG. 4, the flow path of the coolant from the supply port 19 of the rotary joint 11 to the end of the inner pipe 15 on the axial flange 10c side is defined as the forward flow path. Then, the coolant that has flowed up to the axial flange 10c side end portion of the inner tube 15 passes through the opening hole 10k so as to make a U-turn, and is formed in the outer flow formed by the gap between the outer tube 14 and the inner tube 15. It flows into the path, passes through a narrow gap between the inner tube 15 and the rotor 11a, flows through a wide gap formed by the outer tube 14 and the inner tube 15 toward the axial flange 11f, and at this time, the outer tube 14 is cooled by the coolant. Is cooled. Then, the coolant is discharged from the discharge port 13 formed in the casing 11 e of the rotary joint 11 to the outside of the rotary joint 11. In FIG. 4, the flow path of the coolant from the opening hole 10k through the outer flow path to the discharge port 13 is defined as a return flow path.

  In this way, the cooling roller 10 has a reciprocating flow path through which the cooling liquid flows, and forms a closed-loop flow path with the cooling liquid circulation device 500 described later via the rotary joint 11 to circulate the cooling liquid.

  Here, at the position where the coolant flows into the outer flow path from the opening hole 10k of the inner pipe 15 (the end of the outer flow path on the cooling roller axial flange 10c side), the temperature of the coolant is low. 2, the sheet P heated through the heat fixing means 7 passes while contacting the surface of the cooling roller 10, so that the temperature of the coolant flowing through the outer flow path is on the flange 10c side in the cooling roller axial direction. As you go to the rotary joint 21 side, it rises. Therefore, the surface temperature of the outer tube 14 of the cooling roller 10 is lowest on the flange 10c side in the cooling roller axial direction and highest on the rotary joint 20 side in the cooling roller axial direction.

  Therefore, the cooling efficiency of the sheet P by the cooling roller 10 is highest on the flange 10 c side in the cooling roller axial direction of the outer tube 14, and lowest on the rotary joint 20 side in the cooling roller axial direction of the outer tube 14. There is a temperature gradient over the entire width in the roller axis direction, and the temperature difference and cooling efficiency difference also increase.

[Configuration example 1]
Next, the cooling roller 10 and the cooling device 200 according to the configuration example 1 will be described with reference to FIG.

In the present configuration example, as shown in FIG. 1, the maximum width W of the paper P that can be used in the image forming apparatus so that the entire width of the paper P passing through the paper passing area width L in the direction orthogonal to the paper transport direction can be cooled. The two cooling rollers 10, that is, the cooling roller 10 a and the cooling roller 10 b, whose length in the axial direction of the outer tube 14 is shorter than _max , are disposed so as to occupy at least the maximum width W _max of the paper P, and the paper passing area The width L is divided by the cooling roller 10a and the cooling roller 10b to cool the paper P.

  A rotary joint 20 (supply port side) and a rotary joint 21 (discharge port side) are connected to both ends of each cooling roller 10 in the axial direction of the cooling roller as rotary joint means, respectively. It is free to rotate.

  Hereinafter, when the two cooling rollers 10 are specified and indicated, a is added after the reference numerals indicating the respective members of the cooling roller 10 on the left side in the paper conveyance direction, and on the right side in the paper conveyance direction. A distinction is made by adding b after the reference numeral indicating each member of a certain cooling roller 10.

First, the flow of the coolant in the cooling roller 10 will be described with reference to FIG.
In the cooling roller 10a, the cooling liquid is supplied into the cooling roller 10a from the supply port 19a of the rotary joint 20a on the center side of the sheet passing area width L of the cooling roller 10a, passes through the flow path 16a in the outer tube 14a, and is cooled. The ink is discharged from the discharge port 13a of the rotary joint 21a opposite to the rotary joint 20a in the roller axis direction. At this time, the outer tube 14a is cooled by the coolant flowing through the flow path 16a.

  Similarly, in the cooling roller 10b, the coolant is supplied into the cooling roller 10b from the supply port 19b of the rotary joint 20b on the center side of the sheet passing area width L of the cooling roller 10b, and flows through the flow path 16b in the outer tube 14b. As a result, it is discharged from the discharge port 13b of the rotary joint 21b opposite to the rotary joint 20b in the cooling roller axial direction. At this time, the outer tube 14b is cooled by the coolant 1 flowing through the flow path 16b.

  Thus, by having the cooling roller 10a and the cooling roller 10b, the sheet passing area width L is divided into two independent flow paths 16a and 16b, and the rotary joint 20a and the rotary joint 20b are separated. Accordingly, a coolant circulation device 500 as shown in FIG. 12 to be described later and a closed loop flow path are formed to circulate the coolant.

  Here, in the cooling roller 10a, the position at which the coolant flows from the supply port 19a into the flow path 16a in the outer tube 14 (the end of the flow path 16a on the cooling roller axial direction rotary joint 20a side, the center of the sheet passing area width L). 2), the temperature of the coolant is low, but the sheet P heated through the heat fixing means 7 shown in FIG. 2 passes while contacting the surface of the cooling roller 10a. The temperature of the liquid rises from the rotary joint 20a side to the rotary joint 21a side in the cooling roller axial direction. Therefore, the surface temperature of the outer tube 14 of the cooling roller 10a is lowest on the rotary joint 20a side in the cooling roller axial direction and highest on the rotary joint 21a side in the cooling roller axial direction.

  Therefore, the cooling efficiency of the paper P by the cooling roller 10a is highest on the rotary joint 20a side in the cooling roller axial direction of the outer tube 14a, and lowest on the rotary joint 21a side in the cooling roller axial direction of the outer tube 14a.

  Similarly, in the cooling roller 10b, the position at which the cooling liquid flows from the supply port 19b into the flow path 16b in the outer tube 14b (the end of the flow path 16b on the cooling roller axial direction rotary joint 20b side, the center of the sheet passing area width L). 2), the temperature of the coolant is low, but the sheet P heated through the heat fixing means 7 shown in FIG. 2 passes while contacting the surface of the cooling roller 10b. The temperature of the liquid rises from the rotary joint 20b side to the rotary joint 21b side in the cooling roller axial direction. Therefore, the surface temperature of the outer tube 14b of the cooling roller 10b is lowest on the rotary joint 20b side in the cooling roller axial direction, and highest on the rotary joint 21b side in the cooling roller axial direction.

  Therefore, the cooling efficiency of the sheet P by the cooling roller 10b is highest on the rotary joint 20b side in the cooling roller axial direction of the outer tube 14b, and lowest on the rotary joint 21b side in the cooling roller axial direction of the outer tube 14b.

  Therefore, the cooling efficiency of the paper P by the cooling roller 10a and the cooling roller 10b is the highest near the center of the paper passing area width L shown in FIG. 2, and the lowest at both ends of the paper passing area width L. In addition to having a symmetrical temperature gradient around the center of the region width L, the temperature difference in the sheet passing region width direction of the paper P cooled by the cooling roller 10a and the cooling roller 10b can be reduced.

  Further, since the range cooled by the cooling roller 10a and the cooling roller 10b is divided in the sheet passing area width direction of the paper P with the vicinity of the center of the sheet passing area width L as a boundary, the flow path 16a of the cooling roller 10a is divided. The amount of the coolant flowing through the coolant and the coolant flowing in the flow path 16b of the cooling roller 10b receiving the heat of the paper P is about half that when the paper P is cooled by only one cooling roller 10. Therefore, the temperature rise of the cooling liquid flowing through the flow path 16 a and the cooling liquid flowing through the flow path 16 b can be suppressed to be lower than when the paper P is cooled by only one cooling roller 10. As a result, the cooling efficiency of the cooling roller 10a and the cooling roller 10b with respect to the paper P is higher than when the paper P is cooled by only one cooling roller 10, and the cooling efficiency difference in the width direction of the cooling roller is reduced. It is possible to reduce the temperature difference in the width direction of the sheet passing area of the paper P cooled by the cooling rollers 10a and 10b. Thereby, for example, it is possible to prevent the paper P from curling and causing a paper jam in the paper conveyance path from the cooling device 100 to the paper discharge accommodating portion 8.

  Further, as described above, the cooling efficiency becomes the highest in the vicinity of the center of the sheet passing area width L, so that the central portion of the sheet P generally having a high printing rate can be efficiently cooled. Blocking of the central portion of the paper P that is likely to store heat when discharged and stacked on the section 8 can be suppressed.

[Configuration example 2]
Next, the cooling roller 10 according to the configuration example 2 will be described with reference to FIG. As shown in FIG. 5, the cooling roller 10 of this configuration example has a tube structure including an outer tube 14 and a core 30, and a narrow gap formed by the outer tube 14 and the core 30 serves as a flow path through which the coolant flows. .

  In FIG. 5, the cooling liquid cooled by the cooling liquid circulation device 500 as shown in FIG. 12 is supplied to the cooling roller 10 from the supply port 19 of the rotary joint 20 as the rotary pipe joint means. The flow path 16 in the cooling roller 10 has a narrow structure so that only the vicinity of the inner peripheral surface of the outer tube 14 passes water. The outer tube 14 and the outer tube shaft 23 are integrated on the discharge port 13 side of the outer tube 14 in the axial direction of the cooling roller, and the outer tube 14 is rotatably supported by the bearing 22. The coolant that has passed through the flow path 16 is discharged from the discharge port 13. In addition, as shown in FIG. 6, a cooling liquid that is supported in a reserve tank 25 that can store a small amount of cooling liquid through a bearing 24 so that the outer pipe shaft 23 is rotatably supported and the flow path 16 in the outer pipe 14 is passed through. However, a configuration may be adopted in which the gas is discharged from the discharge port 13 of the outer tube shaft 23 into the reserve tank 25. Thereby, since the structure of the joint means by the side of the discharge port 13 of the cooling roller 10 can be simplified, size reduction and cost reduction of an apparatus can be achieved.

  Here, as in the cooling roller 10 shown in FIG. 3, when the volume in the outer tube 14 is large, not only the flow rate of the coolant flowing in the flow path 16 becomes slow, but also flows in the vicinity of the inner peripheral surface of the outer tube 14. It is conceivable that the flow of the cooling liquid may be deteriorated, and that the flow of the cooling liquid flowing through the flow path 16 in the outer tube 14 is likely to be uneven. Cooling unevenness may occur.

  Therefore, as in the present configuration example, the flow path 16 is made narrow so that only the vicinity of the inner peripheral surface of the outer tube 14 can pass through, so that the flow path 16 is compared with the cooling roller 10 shown in FIG. The flow rate of the coolant flowing in the interior 16 is increased, and the cooling efficiency of the outer tube 14 by the coolant flowing in the flow path 16 can be increased. As a result, the cooling efficiency of the cooling roller 10 with respect to the paper P can be increased, and the occurrence of uneven cooling can be suppressed.

[Configuration example 3]
Next, the cooling roller 10 and the cooling device 300 according to the configuration example 3 will be described with reference to FIG. Since the basic configuration of the cooling device 300 is substantially the same as that of the cooling device 100, the description thereof is omitted.

  In the cooling roller 10a, the cooling liquid is supplied into the cooling roller 10a from the supply port 19a of the rotary joint 20a on the center side of the sheet passing area width L of the cooling roller 10a by a cooling liquid circulation device 500 as shown in FIG. It passes through the flow path 16a in the outer tube 14a and is discharged from the discharge port 13a of the rotary joint 21a opposite to the rotary joint 20a in the cooling roller axial direction. At this time, the outer tube 14a is cooled by the coolant flowing through the flow path 16a.

  Similarly, in the cooling roller 10b, the cooling liquid is fed into the cooling roller 10b from the supply port 19b of the rotary joint 20b on the center side of the sheet passing area width L of the cooling roller 10b by a cooling liquid circulation device 500 as shown in FIG. It is supplied, passes through the flow path 16b in the outer tube 14b, and is discharged from the discharge port 13b of the rotary joint 21b on the opposite side of the rotary joint 20b in the cooling roller axial direction. At this time, the outer tube 14b is cooled by the coolant flowing through the flow path 16b.

  As shown in FIG. 7, a case where the width W of the paper P to be passed is narrower than the paper passing area width L and the center of the paper passing area width L is passed will be described.

  In this configuration example, when the width W of the paper P to be passed is narrower than the paper passing area width L, the cooling roller 10a is passed in the paper passing area width direction according to the width W of the paper P and the position to pass the paper. It is configured to be movable in the direction of the parallel width Xa. Similarly, when the width W of the paper P to be passed is narrower than the paper passing area width L, the cooling roller 10b passes in the paper passing area width direction according to the width W of the paper P and the position to pass the paper. It is configured to be movable in the direction of parallel width Xb.

  A configuration in the cooling device 300 that can move in the width Xa direction of the cooling roller 10a and a configuration that can move in the width Xb direction of the cooling roller 10b will be described with reference to FIGS.

  FIG. 8 is an overall configuration diagram of the cooling device 300 when the cooling device 300 is viewed from the sheet conveyance direction side, FIG. 9 is a schematic diagram of the cooling roller 10, and FIG. 10 is a view of the cooling device 300 from above. It is the schematic of the bracket upper board 6u provided in the cooling device 300 in the case of.

  The cooling device 300 is fixed to the image forming apparatus via the bracket side plate 6s. Both ends of the cooling roller 10a and the cooling roller 10b are rotatably supported by the cooling roller side bracket 6a. The cooling roller upper surface bracket 6b is integrated with the cooling roller side surface bracket 6a, and the cooling roller 10a is moved in the width Xa direction by a driving device (not shown) via the moving rail 31 of the bracket upper plate 6u of the cooling device 300 shown in FIG. The cooling roller 10b is movable in the width Xb direction.

  The cooling roller 10a is within a range from the position where the cooling regions of the cooling roller 10a and the cooling roller 10b do not overlap as shown in FIG. 1 to the position where the left end of the cooling region of the outer tube 14 becomes the left end of the paper P. Is moved in the width Xa direction. Similarly, the cooling roller 10b is moved in the width Xb direction within a range where the right end of the coolable region of the outer tube 14 is the right end of the paper P.

  Accordingly, the contact area between the sheet P and the cooling roller 10 is maximized according to the width of the sheet P, and the cooling efficiency is maximized at the center in the width direction of the sheet P. Therefore, the sheet P can be efficiently cooled. Can do.

  Here, this position is in the overlapping region where the paper P is cooled by the cooling roller 10a and the cooling roller 10b, and in the cooling roller axial direction of the outer tube 14a where the coolant temperature is the lowest on the supply port 19 side. The position on the supply port 19a side and the position on the supply port 19b side in the cooling roller axial direction of the outer tube 14b are determined by the relationship between the regions where the cooling efficiency for the paper P by the cooling roller 10a and the cooling roller 10b is the best. The

[Configuration Example 4]
Next, the cooling roller 10 and the cooling device 400 according to the configuration example 4 will be described with reference to FIG. Since the basic configuration of the cooling device 400 is substantially the same as that of the cooling device 100, description thereof is omitted.

  In this configuration example, the width of the sheet P to be passed is either the length of the outer tube 14a of the cooling roller 10a in the axial direction of the cooling roller or the length of the outer tube 14b of the cooling roller 10b in the axial direction of the cooling roller. If the width of the outer tube 14 is smaller than the width of the paper P, the paper P is passed through the cooling roller 10 which is longer in the axial direction of the outer roller 14 than the width of the paper P. Only the cooling roller 10 is driven so that the paper P can be cooled.

  In this configuration example, as shown in FIG. 11, the width W of the paper P is narrower than the width of the outer tube 14a of the cooling roller 10a, in other words, the coolable region of the paper P by the cooling roller 10a. It is assumed that the coolable area of the paper P by the cooling roller 10a is equal to or larger than the coolable area of the paper P by the cooling roller 10b. The paper P passes through the position shown in FIG. 11 so as to pass through the coolable area of the paper P by the cooling roller 10a. At this time, the coolant is circulated by the coolant circulating apparatus 500 as shown in FIG. 12 only to the cooling roller 10a, and the liquid feeding to the cooling roller 10b is stopped.

  In this embodiment, the cooling roller 10a and the cooling roller 10b are rotated together with the conveyance force of the conveyance belt 4 of the cooling device 400. However, the cooling roller 10a and the cooling roller 10b are driven by a motor or the like. In the case of adopting a configuration that is rotationally driven by a driving device consisting of the above, only the cooling roller 10a is rotationally driven, and the cooling roller 10b is stopped without being rotationally driven.

  By such control, the cooling roller 10 (cooling roller 10b in FIG. 11) that reduces the power consumption of the pump for supplying the cooling liquid (reference numeral 52 in FIG. 12 described later) and does not cool the paper P. The power consumption for driving can be reduced.

  Here, when the width W of the paper P is narrower than the coolable region of the cooling roller 10, the heat capacity of the paper P is small or the printing rate of the paper P is low, and the length of the outer tube 14 in the axial direction of the cooling roller is longer than the paper P. When one of the long cooling rollers 10 can sufficiently cool the paper P, the paper P is passed on one side and only the cooling roller on the side through which the paper P is passed is driven to remove the paper P. Cooling is preferred. That is, even when the width W of the paper P is narrower than the coolable region of the cooling roller 10a, for example, the type of the paper P has a high heat capacity such as coated paper, and blocking is likely to occur during stacking after paper discharge. When the in-machine temperature is rising due to continuous use and high ambient temperature, it is desirable to perform control as in Configuration Example 3 shown in FIG.

[Configuration Example 5]
The cooling circulation device 500 shown in FIG. 12 used in the cooling device 100 shown in FIG. 2 sends out the cooling liquid 1 in the tank 51 by the pump 52, and passes from the cooling fan 53 when passing through the radiator 54 as the heat radiating means. In response to the air blowing, heat is radiated to the outside and the temperature of the coolant 1 is lowered (heat exchange between the coolant 1 and the outside). The cooling liquid 1 cooled by the radiator 54 flows in the liquid feeding tube 55, and the flow path of the cooling liquid 1 is divided into two at a branch point J1 of the liquid feeding tube 55. One of the flow paths of the rotary joint 20a of the cooling roller 10a It is supplied from the supply port 19a into the cooling roller 10a and flows through a flow path (not shown) in the cooling roller 10a. The other is supplied into the cooling roller 10b from the supply port 19b of the rotary joint 20b of the cooling roller 10b and flows through a flow path (not shown) in the cooling roller 10b. At this time, the cooling roller 10a or the cooling roller 10b takes away the heat of the sheet P that has become high temperature through the heat fixing means 7 shown in FIG. 2, and the cooling liquid 1 in the cooling roller 10a or the cooling liquid 1 in the cooling roller 10b. Increases (heat exchange between the coolant 1 and the paper P). The cooling liquid 1 in the cooling roller 10a is discharged from the discharge port 13a of the rotary joint 21a of the cooling roller 10a, and the cooling liquid 1 in the cooling roller 10b is discharged from the discharge port 13b of the rotary joint 21b of the cooling roller 10b. The coolant 1 discharged from the discharge port 13 a and the discharge port 13 b becomes one flow path again at the junction J <b> 2 of the liquid supply tube 55, and is sent out by the pump 52 again via the tank 51. Through the circulation of the coolant 1, the heat of the sheet P is repeatedly released to the outside of the cooling device 100.

  In the cooling circulation device 500 shown in FIG. 12, the flow path from the branch point J1 to the supply port 19a of the cooling roller 10a, the flow path from the branch point J1 to the supply port 19b of the cooling roller 10b, and the discharge port 13a of the cooling roller 10a. The flow path to the junction J2, the flow path from the discharge port 13b of the cooling roller 10b to the junction J2, the flow path in the cooling roller 10a (for example, the flow path 16a shown in FIG. 1), and the cooling roller 10b When the structure of the flow path (for example, the flow path 16b shown in FIG. 1) is the same, by supplying the coolant 1 with one pump 52, the supply port 19a and the supply port 19b have the same flow rate and It becomes pressure. Accordingly, the cooling roller 10a and the cooling roller 10b can have the same cooling efficiency as long as there is no influence of heat received from the outside.

  However, when the cooling circulation device 500 is actually mounted on the image forming apparatus or the like, the cooling roller 10a after the coolant 1 passes through the radiator 54, for example, due to a layout problem or a space problem in the image forming apparatus main body. And the flow path to the cooling roller 10b, and the length of the liquid feeding tube 55 connected to the two rotary joints even if the flow path in the cooling roller 10a and the flow path in the cooling roller 10b are the same. It is possible that the lengths are different. At this time, the flow of the cooling liquid 1 flowing in the cooling roller 10a and the cooling liquid 1 flowing in the cooling roller 10b differ due to the effect of pressure loss or the like, and the cooling efficiency of the paper P by the cooling roller 10a and the paper by the cooling roller 10b A difference occurs in the cooling efficiency of P. Further, in addition to the difference in the configuration of the circulation system related to the circulation of the coolant 1, there may be a variation in component accuracy, a variation between lots, and a difference in ambient environmental temperature.

  Therefore, as shown in FIG. 12, a flow rate adjusting valve 56a is provided in the flow path from the branch point J1 to the supply port 19a of the cooling roller 10a, and in the flow path from the branch point J1 to the supply port 19b of the cooling roller 10b. A flow rate adjusting valve 56b is provided to enable adjustment of the flow rate of the cooling liquid 1 supplied to the cooling roller 10a and the cooling roller 10b by a mechanical mechanism, and the cooling efficiency of the sheet P by the cooling roller 10a and the sheet by the cooling roller 10b. By controlling the flow rate of the coolant 1 so that the cooling efficiency of P becomes the same, the variation in cooling of the paper P in the width direction can be minimized.

  FIG. 13 is a schematic configuration diagram of a color image forming apparatus of a tandem type intermediate transfer belt system equipped with a cooling device 100 having the cooling roller 10 of the present invention.

  An intermediate transfer belt 61 as an intermediate transfer medium is stretched by a plurality of rollers, the intermediate transfer belt 61 is configured to rotate by these rollers, and a process unit for image formation is disposed around the intermediate transfer belt 61. ing.

  When the rotation direction of the intermediate transfer belt 61 is indicated by an arrow a in the drawing, image formation is performed in order from the upstream side in the rotation direction of the intermediate transfer belt 61 above the intermediate transfer belt 61 and between the rollers 62 and 63. As the process means, a first image station 64Y, a second image station 64C, a third image station 64M, and a fifth image station 64Bk are arranged. For example, in the first image station 64Y, a charging unit 70Y, an optical writing unit 72Y, a developing unit 73Y, and a cleaning unit 74Y are arranged around a drum-shaped photoconductor 71Y, and the photoconductor 71 is opposed to the intermediate transfer belt 61. A primary transfer roller 75Y as a transfer unit to the intermediate transfer belt 61 is provided at the position, and the other three image stations have the same configuration. These four image stations are arranged side by side so as to have a predetermined pitch interval.

  In the present embodiment, the optical writing means 72 is an optical system using an LED as a light source. However, the optical writing unit 72 can also be configured by a laser optical system using a semiconductor laser as a light source, and exposes the photoconductor 71 according to image information. .

  Below the intermediate transfer belt 61, a sheet storage unit 76 and a sheet feeding roller 77, a registration roller pair 78, and a roller 65 that stretches the intermediate transfer belt 61 are interposed via the intermediate transfer belt 61. A secondary transfer roller 66 serving as a transfer means from the intermediate transfer belt 61 provided so as to face the sheet P and a roller 68 in contact with the back surface of the intermediate transfer belt 61 are opposed to the front surface of the intermediate transfer belt 61. A cleaning unit 69 provided in contact therewith, a thermal fixing unit 7, a cooling device 100 having a cooling roller 10 that cools the paper P, a paper discharge accommodating unit 8 that is a discharge unit of the paper P after toner fixing, and the like are arranged. Yes. A paper conveyance path 79 extending from the paper storage unit 76 to the paper discharge storage unit 8 extends. In order to form an image on the back side when forming a double-sided image, a paper conveyance path 80 for double-sided image formation that reverses the paper P once passed through the cooling device 100 and conveys it again to the registration roller pair 78 is also provided.

  The cooling roller 10 of the cooling device 100 is a heat receiving unit that receives the heat of the paper P, and is connected so as to communicate with the radiator 54, the pump 52, and the tank 51 with the cooling fan 53 through the liquid supply tube 55. Liquid 1 is enclosed. As shown by the arrow of the liquid feeding tube 55, the cooling liquid circulation path supplies the cooling liquid 1 cooled by the radiator 54 to the cooling roller 10, discharges it after passing through the cooling roller 10, and then the tank. 51, the pump 52 is sent to the pump 52 and returned to the radiator 54 again. The coolant 1 is circulated by the rotational pressure of the pump 52, and the radiator 54 radiates heat to cool the coolant 1, and the cooling roller 10. The power of the pump 52, the size of the radiator 54, and the like are selected based on the flow rate, pressure, cooling efficiency, and the like determined by the thermal design conditions (the amount of heat and temperature conditions that the cooling roller 10 should cool).

  The image forming process follows the general electrostatic recording system when paying attention to the first image station 64Y, and is formed by the light writing means 72Y on the photoreceptor 71Y uniformly charged by the charging means 70Y in the dark. An electrostatic latent image is formed by exposure, and the electrostatic latent image is visualized as a toner image by the developing device 73Y. The toner image is transferred from the photoreceptor 71Y to the intermediate transfer belt 61 by the primary transfer roller 75Y. The surface of the photoreceptor 71Y after the transfer is cleaned by the cleaning means 74. The other image stations 64 have the same configuration as the first image station 64Y, and the same image forming process is performed.

  Each developing device 73 in each of the image stations 64Y, 64C, 64M, and 64Bk has a visual image forming function using different four color toners. Yellow, cyan, and magenta are used in each of the image stations 64Y, 64C, 64M, and 64Bk. If black is shared, a full color image can be formed. Therefore, while the same image forming area of the intermediate transfer belt 61 sequentially passes through the four image stations 64Y, 64C, 64M, and 64Bk, the primary is provided to face each of the photoreceptors 71 with the intermediate transfer belt 61 interposed therebetween. If the toner image is overlaid and transferred onto the intermediate transfer belt 61 by the transfer bias provided by the transfer roller 75, the same image forming area will be assigned to each of the image stations 64Y, 64C, 64M and 64Bk. At the time of passing, the full color toner image can be obtained by overlapping transfer on the same image area.

  Then, the full-color toner image formed on the intermediate transfer belt 61 is transferred to the paper P. The intermediate transfer belt 61 after the transfer is cleaned by a cleaning unit 69. During transfer, a transfer bias is applied to the secondary transfer roller 66 via the intermediate transfer belt 61 on the roller 65 at the time of transfer, and the sheet P is transferred to the nip portion between the secondary transfer roller 66 and the intermediate transfer belt 61. This is done by passing it through. After the transfer to the paper P, the full-color toner image carried on the paper P is fixed by the thermal fixing unit 7, thereby forming a full-color final image on the paper P and stacking it on the paper discharge storage unit 8.

  In the image forming apparatus of the present embodiment, the paper P passes through the cooling device 100 disposed immediately after the heat fixing unit 7 before the paper P is stacked in the paper discharge storage unit 8. When passing, the paper P heated by the heat fixing means 7 passes while contacting the cooling roller 10 which is a heat receiving portion. Therefore, the surface of the cooling roller 10 absorbs heat from the paper P, and this heat is absorbed. This is transmitted to the coolant 1 inside the cooling roller 10. After the heat is transferred and the coolant 1 is heated to a high temperature, the coolant 1 is discharged from the cooling roller 10, and the coolant 1 is sent through the tank 51 and the pump 52 to the radiator 54 equipped with the cooling fan 53. Heat is exhausted outside the image forming apparatus. The coolant 1 from which heat has been removed by the radiator 54 and lowered to near room temperature is then sent to the cooling roller 10 again. By such an exhaust heat cycle with high cooling performance by the cooling liquid 1, the paper P heated to a high temperature by the heat fixing means 7 is efficiently cooled. Therefore, when the paper P is stacked in the paper discharge storage unit 8, the toner on the paper P can be surely cured. In particular, it is possible to avoid the blocking phenomenon that has been a serious problem in the double-sided image formation output.

As described above, according to the present embodiment, the cooling roller 10 including the outer tube 14 that is a hollow tubular member and the like, and the pump 52 that is a cooling medium conveying unit that conveys the cooling liquid into the outer tube 14 are provided. In the cooling device 100 that cools the paper P by bringing the paper P that is a sheet-like member into contact with the cooling roller 10, the cooling roller 10 that has a shorter axial width than the maximum width W _{max of the} paper P that can be used in the image forming apparatus. Are disposed so as to occupy the maximum width _Wmax . In the present embodiment, the amount of heat received by the cooling liquid 1 flowing in the cooling rollers 10a and 10b is that the cooling liquid 1 flowing from one end side to the other end side in one cooling roller 10 with the maximum width W _max of the paper P. The amount of heat received is less, and accordingly, the temperature rise of the cooling medium flowing through the cooling rollers 10a and 10b is suppressed. Therefore, the temperature difference in the axial direction of the cooling rollers 10a and 10b can be reduced as compared with the configuration in which the cooling liquid 1 flows from one end side to the other end side in one cooling roller 10 with the maximum width W _max of the paper P. As a result, the difference in cooling efficiency by the cooling roller 10 in the width direction of the paper P can be reduced.
Further, according to the present embodiment, the outer tube 14a is provided with a supply port through which the coolant 1 is supplied into the outer tube 14a at the end on the central side of the maximum width _{Wmax in} the cooling roller axial direction. In addition, by providing a discharge port through which the coolant 1 is discharged from the outer tube 14a on the end side of the maximum width _{Wmax in} the cooling roller axial direction, the vicinity of the center of the sheet passing region width L is provided as described above. Since the cooling efficiency is the highest, the central portion of the sheet P having a high printing rate can be efficiently cooled. Therefore, heat is easily stored when the sheet P is discharged and stacked in the discharge storage unit 8. Blocking of the central portion of the paper P can be suppressed.
Further, according to the present embodiment, the cooling roller 10 includes the core 30 that is a core member having a smaller diameter than the outer tube 14 in the hollow inside of the outer tube 14, and the inner peripheral surface of the outer tube 14 and the outer periphery of the core 30. A flow path through which the coolant flows in a gap formed by the surface. Thereby, since the cooling liquid flows through the narrow gap flow path formed by including the core 30, the flow rate of the cooling liquid in the vicinity of the inner wall of the outer pipe increases, the heat transfer coefficient between the roller inner wall and the cooling liquid increases, As a result, the cooling efficiency of the paper P can be improved.
Further, according to the present embodiment, the cooling roller 10 includes the inner tube 15 having a narrower tube structure than the outer tube 14 in the hollow interior of the outer tube 14, and the coolant is interposed between the outer tube 14 and the inner tube 15. This is a double-pipe structure having an outer flow channel that flows and an inner flow channel through which the coolant flows in the inner tube 15. Thereby, since the flow path of the coolant can be divided between the gap between the outer tube 14 and the inner tube 15 and the inside of the inner tube 15, one is the forward path of the coolant flow and the other is the return path of the coolant flow. can do. Therefore, the inflow / outflow port of the cooling liquid can be provided on one axial side of the cooling roller 10, and space can be saved as compared with the case where the inflow / outflow port of the cooling liquid is provided on both sides in the axial direction of the cooling roller 10. Further, the cooling roller 10 can be easily assembled to a cooling device or an image forming apparatus.
Further, according to the present embodiment, the outer tube and the shaft portion are integrally formed on the end portion side of the maximum width W _max of the cooling roller, and the shaft portion is rotatably supported by the bearing. The discharge port at the outer end of the apparatus is configured so that the cooling medium is discharged into the reserve tank, thereby simplifying the configuration of the joint means on the discharge port 13 side of the cooling roller 10, so that the size of the apparatus can be reduced. Cost reduction can be achieved.
Further, according to the present embodiment, when the width of the paper P in the direction orthogonal to the cooling roller axial direction is narrower than the cooling roller axial width of either the cooling roller 10a or the cooling roller 10b, the paper The sheet P is conveyed to the cooling roller 10a or the cooling roller 10b, which is wider in the cooling roller axial direction than the width of P, and the cooling liquid is allowed to flow only to the cooling roller 10 on the side where the sheet P is conveyed. As a result, the sheet P is cooled only by passing water to one of the cooling roller 10a and the cooling roller 10b, so that the consumption of energy and the like related to the feeding of the cooling liquid can be reduced.
Further, according to the present embodiment, the flow rate adjusting valves 56a and 56b, which are flow rate adjusting means for adjusting the flow rate of the coolant flowing through the cooling roller 10a and the flow rate of the coolant flowing through the cooling roller 10b, are provided. The flow rate adjustment valve controls the flow rate of the coolant flowing through the cooling roller 10a and the flow rate of the coolant flowing through the cooling roller 10b so that the cooling efficiency of the paper P by the roller 10a and the cooling efficiency of the paper P by the cooling roller 10a are the same. By adjusting with 56a and 56b, the variation in cooling in the width direction of the paper P can be minimized.
Further, according to the present embodiment, the toner image forming unit that forms a toner image on the paper P, the thermal fixing unit 7 that fixes the toner image formed on the paper P to the paper P by at least heat, and the thermal fixing. In the image forming apparatus provided with a cooling means for cooling the paper P on which the toner image is fixed by the means 7, the cooling device 100 of the present invention is used as the cooling means, so that curling in the width direction of the paper or fixing is performed. Can reduce image quality and gloss unevenness.

DESCRIPTION OF SYMBOLS 1 Coolant 2 Roller 3 Roller 4 Conveying belt 5 Upper guide 6 Bracket 6a Cooling roller side bracket 6b Cooling roller upper surface bracket 6s Bracket side plate 6u Bracket upper plate 7 Heat fixing means 8 Discharge storage unit 10 Cooling roller 10c Flange 10d Flange 10e Ring 10f Screw 10g Bearing 10h Parallel screw portion 10i Fitting portion 10j Bearing 10k Opening hole 10m Cross-sectional hole 11 Rotary joint 11a Rotor 11b Parallel screw portion 11c Fitting portion 11d Bearing 11e Casing 11f Flange 11g Ring 11h Screw 11i Ring 14 Outlet 13 Pipe 15 Inner pipe 16 Flow path 19 Supply port 20 Rotary joint 21 Rotary joint 22 Bearing 23 Outer pipe shaft 24 Bearing 25 Reserve tank 29 Rotary cylinder Into 30 Core 31 Moving rail 51 Tank 52 Pump 53 Cooling fan 54 Radiator 55 Liquid feeding tube 56a Flow rate adjusting valve 56b Flow rate adjusting valve 61 Intermediate transfer belt 62 Roller 63 Roller 64 Image station 65 Roller 66 Secondary transfer roller 68 Roller 69 Cleaning means DESCRIPTION OF SYMBOLS 70 Charging means 71 Photoconductor 72 Optical writing means 73 Developing device 74 Cleaning means 75 Primary transfer roller 76 Paper storage part 77 Paper feed roller 78 Registration roller pair 79 Paper conveyance path 80 Paper conveyance path 100 Cooling device 200 Cooling device 300 Cooling device 400 Cooling device 500 Cooling circulation device

JP 2006-003819 A

Claims (10)

A cooling roller made of a hollow tubular member;
Cooling medium conveying means for conveying the cooling medium into the tubular member,
In the cooling device that cools the sheet-like member by bringing the sheet-like member into contact with the cooling roller,
A cooling device, wherein at least two cooling rollers having an axial width shorter than a maximum width of a sheet-like member usable in an image forming apparatus are disposed so as to occupy the maximum width. The cooling device of claim 1.
The tubular member is provided with a supply port through which the cooling medium is supplied into the tubular member at the end of the central portion of the maximum width in the cooling roller axial direction, and the end of the maximum width in the cooling roller axial direction A cooling device, characterized in that a discharge port through which the cooling medium is discharged from the tubular member is provided on the side. The cooling device according to claim 1 or 2,
The tubular member is attached to at least the end portion on the central portion side of the maximum width in the axial direction of the cooling roller so that the tubular member can be rotated, and the tubular member and the cooling medium supply / conveyance means rotate. Having pipe fitting means;
Both ends of the tubular member in the axial direction of the cooling roller are supported in a fitting relation so as to be rotatable to the main body of the apparatus or the structure of the image forming apparatus. The cooling device according to claim 1, 2 or 3,
A hollow core of the outer tube, which is the tubular member, includes a core member having a smaller diameter than the outer tube, and the cooling roller is a gap formed by the inner peripheral surface of the outer tube and the outer peripheral surface of the core member. A cooling device characterized by having a flow path through which a cooling medium flows. The cooling device according to claim 1, 2 or 3,
An inner pipe having a narrower tube structure than the outer pipe is contained in the hollow inside of the outer pipe, which is the tubular member, and the cooling roller has an outer flow path through which a cooling medium flows between the outer pipe and the inner pipe, and A cooling apparatus having a double pipe structure having an inner flow path through which a cooling medium flows in the inner pipe. The cooling device according to claim 1, 2, 3, 4 or 5,
The outer tube and the shaft portion are integrally structured on the end portion of the maximum width of the cooling roller, the shaft portion is rotatably supported by a bearing, and a cooling medium is provided at the discharge port at the outer end of the apparatus. A cooling device configured to be discharged into a reserve tank. The cooling device according to claim 1, 2, 3, 4, 5 or 6.
The first cooling roller and the second cooling roller are provided so as to be movable in a direction orthogonal to the conveying direction of the sheet-like member,
In the direction perpendicular to the conveyance direction of the sheet-shaped medium, the central portion in the width direction of the conveyed sheet-shaped medium overlaps the flow path of the first cooling roller and the flow path of the second cooling roller in the sheet passing width. A cooling device, wherein at least one of the first cooling roller and the second cooling roller is moved in the orthogonal direction so as to pass through a position in a substantially central portion of the range. The cooling device according to claim 1, 2, 3, 4, 5, 6 or 7,
When the width of the sheet-like member in the direction orthogonal to the conveying direction is narrower than the width of either the first cooling roller or the second cooling roller in the cooling roller axial direction, the sheet-like member The sheet-like member is conveyed to the first cooling roller or the second cooling roller, and the width of the sheet-like member is conveyed only to the cooling roller on the side where the sheet-like member is conveyed. A cooling device characterized by flowing a cooling medium. The cooling device according to claim 1, 2, 3, 4, 5, 6, 7 or 8.
A flow rate adjusting means for adjusting a flow rate of the cooling medium flowing through the first cooling roller and a flow rate of the cooling medium flowing through the second cooling roller;
The flow rate of the cooling medium flowing through the first cooling roller and the first cooling rate are set so that the cooling efficiency of the sheet-like member by the first cooling roller and the cooling efficiency of the sheet-like member by the second cooling roller are the same. A cooling device, wherein the flow rate of the cooling medium flowing through the two cooling rollers is adjusted by the flow rate adjusting means. Toner image forming means for forming a toner image on a sheet-like member;
Thermal fixing means for fixing the toner image formed on the sheet-like member to the sheet-like member at least by heat;
An image forming apparatus comprising: a cooling unit that cools the sheet-like member on which the toner image is fixed by the heat fixing unit;
An image forming apparatus using the cooling device according to claim 1, 2, 3, 4, 5, 6, 7, 8, or 9 as the cooling unit.

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