Regulating temperature of a roller device

A roller device includes a cylinder member. The cylinder member includes wall member having a plurality of channels that are disposed within the wall member. The channels circulate a fluid therein to uniformly regulate a temperature of the cylinder member.

BACKGROUND

Image forming apparatuses, such as liquid electrophotography (LEP) systems, form images on media. Liquid electrophotography systems include a fluid applicator unit, a photoconductive member, an image transfer member, and an impression member. The image formed on the photoconductive member is transferred to the image transfer member, and then is provided to the media. An impression member may be used to transfer the image from the image transfer member to the media. Regulating the temperature of the media may be used to assist with the transfer of the image to the media.

DETAILED DESCRIPTION

A roller device, such as an impression member, is described herein. During the printing process, the temperature of the paper may need to be regulated to avoid low print quality. For example, the amount of friction between the roller device and the media may cause the impression drum to obtain a temperature above or below a predetermined temperature for printing, i.e., above or below fifty degrees Celsius. Consequentially, the temperature of the media may vary above or below the predetermined temperature, potentially resulting in low print quality. Accordingly, efficiently and uniformly regulating the temperature of a roller device to maintain the media at the predetermined temperature is desired.

Regulating the temperature of the roller device may also regulate the temperature of the media. For example, the friction between a thin media and the roller device may cause the roller device to reach a temperature in excess of the predetermined temperature, resulting in the media heating to a temperature above fifty degrees Celsius. Conversely, the friction between a thick media and the roller device may cause the roller device to reach a temperature below the predetermined temperature, resulting in the media cooling to a temperature below the predetermined temperature. Moreover, the temperature of the roller device may need to be adjusted between print jobs, when, for example, the media for the first print job is a thick media and the media for the second print job is a thin media. Thus, efficiently and uniformly regulating the temperature of the roller device may assist with regulating the temperature of the media.

In examples, the roller device includes, among other things a cylinder member rotatable about a longitudinal axis. The cylinder member also includes a wail member, an exterior surface disposed on an outer surface of the wall member, and a plurality of channels disposed within the wall member. The plurality of channels circulate a fluid therein to uniformly regulate a temperature of the cylinder member. The wall surface is disposed adjacent to an intermediate transfer member to press media against the intermediate transfer member to transfer an image from the intermediate transfer member to the media.

FIG. 1is a schematic view illustrating an image forming apparatus, such as a liquid electrophotography system (LEP), according to an example. The LEP100includes an image forming unit12that receives a media S from an input unit11and outputs the media S to an output unit13. The image forming unit12includes a photoconductive member14on which images can be formed. The photoconductive member14may be charged with a suitable charger (not illustrated), such as a charge roller. Portions of the outer surface of the photoconductive member14that correspond to the features of the image can be selectively discharged by a laser writing unit15to form an electrostatic and/or latent image thereon.

Referring toFIG. 1, the LEP100also includes an applicator unit16to apply ink, such as a liquid toner, for example, ElectroInk, trademarked by Hewlett-Packard Company, to the electrostatic and/or latent image on the photoconductive member14. The ink is applied to the photoconductive member14to form a fluid image to be transferred to a roller system17, including an intermediate transfer member (ITM)18and a roller device19, such as an impression member, for example, an impression drum. The ITM18receives the fluid image from the photoconductive member14, heats the fluid image, and transfers the fluid image to the media S. Heat from the ITM18may also transfer to the roller device19. During the transfer of the fluid image from the ITM18to the media S, the media S is pinched between the ITM18and the roller device19. Once the fluid image has been transferred to the media S, the media S can be transported to the output unit13

FIG. 2is a block diagram illustrating an image forming apparatus200according to an example. The image forming apparatus200may be a LEP (100). The image forming apparatus200includes a roller system17with an ITM18and a roller device19. The roller device19may be, for example, an impression drum, such as, a cast iron impression drum weighing approximately four hundred kilograms with a diameter of approximately three hundred and ninety millimeters and a length of approximately nine hundred millimeters.

FIG. 3illustrates a cross-sectional view of a portion of the longitudinal axis of the roller system17according to an example. Referring toFIGS. 2-3, the roller device19is disposed adjacent to the ITM18. The roller device19includes a cylinder member20rotatable about a longitudinal axis. The cylinder member20includes a wall member22, an exterior surface24, and a plurality of channels26. The wall member22forms a portion of the cylinder member20. An outer surface of the wall member22forms the exterior surface24. The exterior surface24may be, for example, a circumferential surface. The exterior surface24presses the media S against the ITM18to transfer the image from the ITM18to the media S. An example of the media S is paper, but the media is not limited to paper.

The plurality of channels26are disposed within the wall member22. The plurality of channels26may be, for example twenty millimeter holes milled into the wall member22A fluid is circulated through the plurality of channels26to uniformly regulate a temperature of the cylinder member20. The fluid circulated may include a temperature regulating substance, such as water, imaging oil, or the like. The arrangement of the plurality of channels26may vary. For example, the arrangement of the plurality of channels26include a plurality of main channel portions31and a plurality of transitional channel portions32disposed between at least two of the plurality of main channel portions31. The configuration of the plurality of channels26allow for efficient and uniform circulation of the fluid within the wall member22, which maintains the temperature of the outer surface24of the roller device19at a predetermined temperature. This configuration is important during printing, such that the fluid is circulated through the plurality of channels26in a manner that maintains the exterior surface24at a contestant temperature and/or adjusts the temperature of the exterior surface24for increases or decreases thereto.

Moreover, the roller device19with the plurality of channels26may increase productivity of the image forming apparatus by minimizing the transient time needed to heat and/or cool the roller device19between changing of a printing media and/or between print jobs. For example, a fluid, such as water, is circulated through the plurality of channels26that extend longitudinally within the wall member22close to the exterior surface24to efficiently and uniformly heat and/or cool the exterior surface24. Water may be selected over air due to water's heating capacity of 4.2 KJ/Kg° C. and thermal conductivity of 0.58 Watt/meter° K, which enable the heat flow to be transferred more efficiently with lower mass flow. In such a case, the roller device10may be quickly heated and/or cooled, which can reduce the amount of down time between print jobs and increase productivity of the image forming apparatus.

FIG. 4is a perspective view of a portion of the roller device ofFIG. 3according to an example.FIG. 5is a cross-sectional view illustrating a portion of the roller device ofFIG. 3according to an example. Referring toFIGS. 3-5, the plurality of main channel portions31extend longitudinally across the cylinder member22with each of the plurality of main channel portions31disposed approximately parallel to each other. As illustrated inFIG. 3, the roller system17may further include an inlet tube33attached to the cylinder member20of the roller device19to transport the fluid to the plurality of channels26, and an outlet tube35attached to the cylinder member20to transport the fluid out of the plurality of channels26.

For example, the inlet tube33may connect to at least one of the plurality of channels26to circulate the fluid throughout the plurality of channels26. The inlet tube33may be connected directly to at least one of the plurality of main channel portions31, the plurality of transitional channel portions32, and/or inlet auxiliary tubes34to assist with providing the fluid to the plurality of channels26from the inlet tube33. The outlet tube35may similarly be connected to at least one of the plurality of main channel portions31, the plurality of transitional channel portions32, and/or outlet auxiliary tubes (not illustrated) to assist with transporting the fluid out of the plurality of channels26through the outlet tube35.

The rotary joint36may connect to the inlet tube33and the outlet tube35to enable rotation of the roller device19, while enabling linear fluid flow into and/or out of the roller device19. The rotary joint36may also connect the inlet tube33and/or the outlet tube35to the roller device19. The inlet tube33may, for example, encase the outlet tube35between the rotary joint36and the roller device19, as illustrated inFIG. 3. For example, the inlet tube33may pass through the rotary joint36, extend to the roller device19, and connect to the plurality of channels26. The fluid may flow from the inlet tubes33inside the roller device19and spread towards the exterior surface24in a radial direction through the roller device19to the plurality of main channel portions31, which extend longitudinally therein. The plurality of main channel portions31may also be connected to the outlet tube35, which may be connected to the rotary joint36to take the fluid out of the plurality of channels26through the rotary joint36. Further, the connection to the rotary joint36includes a seal to prevent fluid from leaking.

FIGS. 4-5illustrate an example of the roller device19fluid paths42, where the plurality of main channel portions31are disposed approximately parallel to each other. The arrows ofFIG. 4illustrate the fluid path42through the plurality of main channel portions31and the plurality of transitional channel portions32. For example,FIGS. 4-5illustrate the fluid path42provided from the inlet tube33to four of the plurality of main channel portions31, indicated as references52and56. The fluid is circulated through the plurality of main channel portions31and the plurality of transitional channel portions32of the plurality of channels26until the fluid reaches two of the plurality of main channel portions31, indicated as references54and58, which are connected to the outlet tube35to transport the fluid out of the plurality of channels26. Note, the fluid may be provided to the plurality of main channel portions31within the wall member22(i.e., references52,56) and transported out of the plurality of channels26at multiple locations (i.e., references54,58). As illustrated in the example, the inlet tubes33may provide the fluid to the plurality of main channel portions31within the wall member22and the fluid may be transported out of the plurality of channels26via a single outlet tube35.

FIGS. 6A and 6Bprovide further examples of the fluid path42through the plurality of channels26in the wall member22using two additional channel configurations. The examples inFIGS. 6A and 6Billustrate the fluid path42with arrows and the plurality of transitional channel portions32disposed between at least two of the plurality of main channel portions31. ReferringFIG. 6A, an example of the plurality of main channel portions31extending longitudinally across the cylinder member20in a skewed arrangement62is illustrated.FIG. 6Aalso illustrates that the inlet tube33and outlet tube35may located on the same side of the roller device19with a dual flow rotary joint36; however, the inlet tube33and the outlet tube35may be located on opposite sides of the roller device19, as illustrated inFIG. 6B. Referring toFIG. 6B, an example of the plurality of main channel portions31that extend longitudinally across the cylinder member20in a traverse arrangement64is illustrated.FIG. 6Billustrates the flow of the fluid, such that the fluid enters the cylinder member20through the inlet tube33on the left side and exits through the outlet tube35located on the right side of the roller device19. Note that the example illustrated inFIG. 6Bincludes two rotary joints36. One rotary joint36is attached to the inlet tube33and the other rotary joint36is connected to the outlet tube36.

As illustrated inFIGS. 4-6B, the plurality of main channel portions31extend longitudinally across the roller device19to uniformly regulate the temperature of the roller device19. For example, the plurality of main channel portions31may include one of the plurality of main channel portions31extending longitudinally across the cylinder member20, as illustrated inFIGS. 4 and 6Abelow and/or the plurality of main channel portions31that, as a whole, extend longitudinally across the cylinder member20, as illustrated inFIG. 6B. By having the plurality of channels extend longitudinally across the roller device19, the fluid circulated through the plurality of channels26may efficiently and uniformly regulate the temperature of the roller device19, as the plurality of channels26illustrated in the examples provide heating and/or cooling over the longitudinal area of the roller device19.

Referring back toFIG. 3, the roller device may further include a sealing unit37in the wall member22to seal the fluid within the plurality of channels26and enable circulation of the fluid through the plurality of channels26. The sealing unit37is illustrated as being disposed in the plurality of transitional channel portions32. The sealing unit37may include at least one of an o-ring38and a gasket39to seal the wall member22of the cylinder member20. As illustrated inFIG. 3, the wall member22may be, for example, plugged and sealed in the plurality of transitional channel portions32through use of an o-ring38and a gasket39. The sealing unit37is designed to prevent leakage of the fluid after the plurality of channels26are drilled into the side of the wall member22.

FIG. 7is a flowchart illustrating a method700of regulating temperature of a roller device of an image forming apparatus according to an example. Referring toFIG. 7, in block72, a temperature value of the cylinder member20of the roller device19is periodically identified. In block74, a regulating temperature range is determined based on the identified temperature value and a predetermined acceptable temperature range for the cylinder member20. For example, the regulating temperature range may be between forty-seven degrees Celsius and fifty-three degrees Celsius or between forty-nine degrees Celsius and fifty-one degrees Celsius. In block76, a fluid having the regulating temperature range is circulated through a plurality of channels26disposed within a wall member22of the cylinder member20of the roller device19. The method700may be repeated at regular and/or irregular intervals depending on the desired schedule.

The method700may, for example, measure the temperature value of the exterior surface24of the cylinder member20. Then, based on the temperature value, the fluid that is circulated through the plurality of channels26may be transported out of the cylinder member20to a temperature regulating device (i.e., via the outlet tube35), where the fluid is placed in a tank and reused. The temperature regulating device may maintain the fluid at the regulating temperature range by alternating circulation of the fluid through a heater in a heating mode and a heat exchanger connected to a cooling device in a cooling mode, based on the identified temperature value of the cylinder member20. For example, the cooling device may provide chilled fluid to the heat exchanger to lower or cool the temperature of the fluid.

The method700may alternate between a heating mode and a cooling mode based on the temperature of the cylinder member20to efficiently and uniformly maintain and/or change the temperature of the roller device for high quality printing. For example, the temperature of the cylinder member20may be maintained using the method700. When the identified temperature value reaches, for example, three or more degrees Celsius over the predetermined acceptable temperature range, the heaters may be turned off and the heat exchanger may receive chilled fluid from the cooling device. In the cooling mode, after the fluid is sent through the heat exchanger, the cooled fluid may be circulated back into the plurality of channels26(i.e., via the inlet tube33). Similarly, when the temperature value of the cylinder20is, for example, three or more degrees Celsius under the predetermined acceptable temperature range, the heater may be turned on and the fluid may be circulated through the temperature regulating device to be heated. In the heating mode, the fluid that is circulated through a heater to heat the fluid and may be circulated back through the plurality of channels26(i.e., via the inlet tube33).

Moreover, the method700may be repeated continually and/or periodically to monitor the temperature value of the cylinder member20to verify that the cylinder member20is being kept within the predetermined acceptable temperature range. An example includes repeating one or more of the following: the identification of the temperature value of the cylinder member20(block72), the determination of the regulating temperature range (block74), and the circulation of the fluid with the regulating temperature range (block76). When the temperature is within the predetermined acceptable temperature range, the fluid continues to circulate; however, when the temperature value of the cylinder member is outside the predetermined acceptable temperature range the regulating temperature range is adjusted accordingly. Furthermore, the heater and/or heat exchanger may adjust to heat and/or cool the fluid at different rates depending on the identified temperature value. Adjusting the rate of heating and/or cooling allows the method700in combination with the roller device19to efficiently and uniformly maintain and/or change the temperature of the fluid circulated through the plurality of channels26in the roller device19during printing.

The present disclosure has been described using non-limiting detailed descriptions of examples thereof and is not intended to limit the scope of the present disclosure. It should be understood that features and/or operations described with respect to one example may be used with other examples and that not all examples of the present disclosure have all of the features and/or operations illustrated in a particular figure or described with respect to one of the examples. Variations of examples described will occur to persons of the art. Furthermore, the terms “comprise,” “include,” “have” and their conjugates, shall mean, when used in the present disclosure and/or claims, “including but not necessarily limited to.” It is noted that some of the above described examples may include structure, acts or details of structures and acts that may not be essential to the present disclosure and are intended to be exemplary. Structure and acts described herein are replaceable by equivalents, which perform the same function, even if the structure or acts are different, as known in the art. Therefore, the scope of the present disclosure is limited only by the elements and limitations as used in the claims.