System and method for regulating temperature of inkjet printhead during duplex printing operations

Abstract

SOLUTION: An inkjet printer includes a pair of temperature regulation modules 36 mounted on opposite sides of each printhead in the printer. Each temperature regulation module includes a thermoelectric cooling device 220 that is activated by a controller when the temperature of the printhead exceeds a predetermined setpoint.EFFECT: By cooling the printheads, the temperature of the printheads can be kept in a temperature range that enables fast drying inks to obtain their optimal performance and that prevents duplex printing operations from raising the temperature of the printheads significantly above the predetermined setpoint.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] The present disclosure generally relates to devices for generating ink images on a medium, and more particularly to regulating the print head temperature of such devices during printing.

Background Art

[0002] An inkjet imaging device, also known as an inkjet printer, ejects liquid ink from a print head to form an image on an image receiving surface. The print head includes a plurality of inkjets arranged in an array. Each inkjet has a piezoelectric actuator coupled to a print head controller. The print head controller generates a firing signal corresponding to digital data content corresponding to an image. The actuators within the print head respond to the firing signal by expanding within the ink chamber to eject ink droplets onto the image receiving surface, forming an ink image corresponding to the digital image content used to generate the firing signal. The image receiving surface is typically a continuous web of media material or a series of media sheets.

[0003] Inkjet printers used to produce color images typically include multiple printhead assemblies. Each printhead assembly typically contains one or more printheads that eject a single color of ink. In a typical inkjet color printer, four printhead assemblies are positioned in the process direction, with each printhead assembly ejecting a different color of ink. The four most frequently used ink colors are cyan, magenta, yellow, and black. The common name for such a printer is a CMYK color printer. Some CMYK printers have two printhead assemblies, each printing one color of ink. Printhead assemblies printing the same color of ink are offset from each other by half the distance between adjacent print jets in the cross-process direction, doubling the density of pixels per inch of the color lines of ink ejected by the printheads in the two assemblies. As used herein, the term “process direction” means the direction of movement of the image-receiving surface as it passes through the printheads in the printer, and the term “cross-process direction” means the direction perpendicular to the process direction in the plane of the image-receiving surface.

[0004] Image quality in a color inkjet printer depends on at least three parameters: color gamut, granularity, and ink droplet satellite. Color gamut can be addressed by using faster-drying inks. Fast-drying inks allow more ink to be deposited on the image. Furthermore, the dryer evaporates the ink more quickly, allowing more ink to be distributed onto the medium without offsetting the ink to the rollers that move the medium through the printer.

[0005] Granulation, more specifically overlay granulation, can also be addressed by quick-drying inks, as ink droplets adhere to the medium more quickly and become immobilized faster. The main cause of overlay granulation is the shear force acting on the ink droplets, which increases the wet-drop-on-wet-drop interaction that mixes the ink droplets with each other. Therefore, as fluidity decreases, the interaction of ink droplets decreases, and as a result, overlay granulation decreases. The best overlay granulation performance of some quick-drying inks is achieved when the printhead temperature setpoint changes from the current target of 37°C to a lower temperature of 32°C. In addition, the stability of inkjet ejecting quick-drying inks is more robust when the printhead temperature is maintained in the range of approximately 30°C to approximately 32°C. Maintaining the printhead temperature in this range is very difficult when heavy media stock is printed on both sides, as the heavy stock absorbs heat as the sheet passes through the printhead and returns to the printing zone for double-sided printing. Some of this absorbed heat is transferred to the printhead, raising the printhead temperature. An increase in printhead temperature can negatively impact the optimal performance of quick-drying inks and lead to drying of the ink on the nozzle plate and within the nozzles. When the ink on the nozzle plate and within the nozzles dries, the inkjet will cease to function. As used herein, the term "malfunctioning inkjet" means an inkjet that does not eject any ink droplets at all, or an inkjet that ejects ink droplets away from the normal between the inkjet nozzle and the ink-receiving surface. Maintaining the effectiveness of quick-drying inks will be beneficial by adjusting the printhead temperature within the effective range of the ink. [Overview of the project]

[0006] A color inkjet printer is configured to regulate the printhead temperature, particularly during double-sided printing of heavy stock. The color inkjet printer includes a printhead configured to eject ink droplets, a sensor configured to generate a signal indicating the printhead temperature, a first thermoelectric cooler configured to remove heat from the printhead, and a controller operably connected to the sensor and the first cooler. The controller is configured to operate the first cooler to remove heat from the printhead in response to a signal generated by the sensor indicating that the printhead temperature is above a predetermined temperature setpoint.

[0007] A method for operating a color inkjet printer regulates the printhead temperature, particularly during double-sided printing of heavy stock. This method includes generating a signal indicating the temperature of the printhead within the inkjet printer, comparing the generated signal to a predetermined temperature setpoint, and operating a first thermoelectric cooling device to remove heat from the printhead in response to a signal generated by a sensor indicating that the printhead temperature is higher than the predetermined temperature setpoint.

[0008] A thermal control module is configured to be selectively attached to and detached from the print head of a color inkjet printer in order to regulate the print head temperature. The thermal control module includes a bracket, a first heat transfer member attached to the bracket, and a first thermoelectric cooling device attached to the first heat transfer member, the first thermoelectric cooling device configured to remove heat from the first heat transfer member.

[0009] The print head is configured to regulate the print head temperature in a color inkjet printer. The print head includes a print head having multiple inkjet printers, each inkjet printer comprising a piezoelectric transducer for ejecting ink droplets, a heat transfer member attached to a first side of the print head, and a thermoelectric cooling device attached to the heat transfer member and configured to remove heat from the heat transfer member. [Brief explanation of the drawing]

[0010] The aforementioned aspects and other features of a color inkjet printer that adjusts the print head temperature and a method of operating the color inkjet printer are described below in relation to the attached drawings.

[0011] [Figure 1] This is a schematic diagram of a color inkjet printer that adjusts the print head temperature. [Figure 2A] Figure 1 is a side cross-sectional view of a print head configured to include a pair of temperature control modules inside a printer. [Figure 2B] This is a perspective view of a replaceable temperature control module mounted around the print head. [Figure 3] Figure 1 is a block diagram of the components of the printer that regulate the temperature of the print head inside the printer. [Figure 4] This is a flowchart of the process for operating the temperature control module shown in Figure 1. [Figure 5] This is a schematic diagram of a conventional color inkjet printer that cannot maintain the printhead temperature within a range effective for using fast-drying ink with heavy stock during double-sided printing. [Figure 6] Figure 5 shows the printing zone of the printer. [Modes for carrying out the invention]

[0012] For a general understanding of the environment for the printers and methods of operation disclosed herein, as well as for details of the printers and methods of operation, refer to the drawings. In the drawings, similar reference numerals are used throughout to specify similar elements. As used herein, the word “printer” encompasses any device that sprays ink droplets onto different types of media to form an ink image.

[0013] The printer and method described below utilize thermoelectric cooling devices on both sides of the piezoelectric printhead in the process direction to remove heat from the piezoelectric printhead when the printhead temperature falls outside a predetermined range. By setting the upper threshold of the range to 32°C and the lower threshold to 30°C, the printhead temperature can be maintained within a range that helps maintain the operating state of the piezoelectric inkjet within the printhead, ensuring optimal performance of the fastest-drying inks and especially during duplex printing jobs using heavy stocks.

[0014] Figure 5 shows a conventional high-speed color inkjet printer 10 in which the piezoelectric print head of the printer is not cooled. As illustrated, the printer 10 is a printer that directly forms an ink image on the surface of a medium sheet taken from one of a medium sheet supply unit SS1 or S2, the sheet S being moved through the printer 10 by a controller 80 that operates one or more actuators 40, the actuators 40 being operably connected to rollers of a conveyor 52 or at least one driven roller, the conveyor 52 comprising a portion of a medium transport unit 42 that passes through the printer's printing zone PZ (shown in Figure 6). In one embodiment, each print head module has only one print head having a width corresponding to the widest medium width in the cross-process direction that can be printed by the printer. In other embodiments, the print head module has multiple print heads, each print head having a width less than the widest medium width in the cross-process direction that the printer can print. In these modules, the print heads are arranged in an array of staggered print heads that allows for printing on medium wider than a single print head. In addition, the print heads within or between modules can also be combined such that the density of droplets ejected by the print heads in the cross-process direction is greater than the minimum spacing between inkjet prints within the print heads in the cross-process direction. Although printer 10 is shown to have only two media sheet feeders, the printer can consist of three or more sheet feeders, each containing a different type or size of media.

[0015] Figure 6 shows the print zone PZ in the prior art printer 10 shown in Figure 5. The print zone PZ has a length in the process direction equal to the distance from the first inkjet through which the sheet passes in the process direction to the last inkjet through which the sheet passes in the process direction, and a width which is the maximum distance between the outermost inkjets on either side of the print zone that are directly opposite each other in the cross-process direction. Each print head module 34A, 34B, 34C, and 34D shown in Figure 6 has three print heads 204 mounted on one of the print head carrier plates 316A, 316B, 316C, and 316D, respectively.

[0016] As shown in Figure 5, the printed image passes under the image dryer 30 after the ink image has been printed on the sheet S. The image dryer 30 may include an infrared heater, a heated air blower, an air return, or a combination of these components to heat the ink image and fix the image to the web at least partially. The infrared heater applies infrared heat to the printed image on the surface of the web to evaporate the water or solvent in the ink. The heated air blower uses a fan or other pressurized air source to direct heated air over the ink to supplement the evaporation of water or solvent from the ink. The air is then collected and exhausted by the air return to reduce interference of the dryer airflow with other components in the printer.

[0017] The dual path 72 is provided to receive the sheet from the transport system 42 after the substrate has been printed and to move the sheet by the rotation of rollers in the opposite direction to the direction of movement through the print head. At position 76 in the dual path 72, the substrate can be inverted so that it can join the job stream being carried by the media transport system 42. The controller 80 is configured to selectively flip the sheet. That is, the controller 80 can operate the actuator to flip the sheet so that the back side of the sheet can be printed, or it can operate the actuator so that the sheet is returned to the transport path without flipping the sheet so that the printed side of the sheet can be printed again. Access to the dual path 72 is provided by the movement of the pivot member 88. The rotation of the pivot member 88 is controlled by the controller 80 which selectively operates the actuator 40 operably connected to the pivot member 88. As shown in Figure 5, when the pivot member 88 is rotated counterclockwise, the substrate from the media transport unit 42 is redirected to the dual path 72. By rotating the pivot member 88 clockwise from its direction change position, access to the dual path 72 is closed, and the substrate on the media transport unit moves to the container 56. Another pivot member 86 is positioned between position 76 in the dual path 72 and the media transport unit 42. When the controller 80 operates the actuator to rotate the pivot member 86 counterclockwise, the substrate from the dual path 72 merges into the job stream on the media transport unit 42. By rotating the pivot member 86 clockwise, access to the dual path to the media transport unit 42 is closed.

[0018] As further shown in Figure 5, printed media sheets S that were not redirected to the dual path 72 are transported by the media transport unit to a sheet container 56 where these sheets are collected. Before the printed sheets reach the container 56, they pass through an optical sensor 84. The optical sensor 84 generates image data of the printed sheets, and this image data is analyzed by the controller 80. The controller 80 is configured to detect streaks in the printed image on the media sheets of the print job. In addition, sheets with test pattern images printed on them are inserted at intervals during the print job. These test pattern images are analyzed by the controller 80 to determine which inkjet actually ejected ink, if present, and if an inkjet ejected an ink droplet, whether the ink droplet landed in its intended location with the correct mass. Any inkjet that does not eject the ink droplet it was expected to eject, or ejects a droplet that does not have the correct mass, or lands in the wrong location is referred to herein as a non-functioning inkjet. The controller can store data identifying non-functioning inkjet in a database 92 operably connected to the controller. These sheets, on which test patterns are printed, may be called run-time missing inkjet (RTMJ) sheets, and these sheets are discarded from the print job output. The user can operate the user interface 50 to obtain a report displayed on the interface that identifies the number of non-functioning inkjet and the print head where the non-functioning inkjet is located. The optical sensor 84 may be a digital camera, an array of LEDs and photodetectors, or other devices configured to generate image data of the surface being passed over. As already mentioned, the media transport unit also includes a dual path that can invert the sheet and return it to the transport unit in front of the print head module, thereby enabling printing on the opposite side of the sheet.Figure 5 shows printed sheets collected in a sheet container, which can be directed to other processing stations (not shown) that perform tasks such as folding, collating, binding, and stapling of the media sheets.

[0019] The operation and control of various subsystems, components, and functions of the machine or printer 10 are carried out with the help of a controller or electronic subsystem (ESS) 80. The ESS or controller 80' is operably connected to the components of the print head modules 34A-34D (and thus the print heads), actuators 40, and dryer 30. The ESS or controller 80 is a self-contained computer having, for example, a central processor unit (CPU) with electronic data storage and a display or user interface (UI) 50. The ESS or controller 80 includes, for example, sensor inputs and control circuits, as well as pixel arrangement and control circuits. In addition, the CPU reads, captures, prepares, and manages the flow of image data between the image input source, such as a scanning system or online or workstation connection (not shown), and the print head modules 34A-34D. Thus, the ESS or controller 80 is the main multitasking processor for operating and controlling all other machine subsystems and functions, including the printing process.

[0020] The controller 80 can be implemented using a general-purpose or dedicated programmable processor that executes program instructions. Instructions and data required to perform the programmed functions can be stored in memory associated with the processor or controller. The processor, their memory, and interface circuits constitute the controller to perform the operations described below. These components may be provided on a printed circuit card or as circuits within an application-specific integrated circuit (ASIC). Each circuit may be implemented on a separate processor, or multiple circuits may be implemented on the same processor. Alternatively, the circuits can be implemented as individual components or circuits provided within a very large-scale integrated (VLSI). Furthermore, the circuits described herein can be implemented in combination of processors, ASICs, individual components, or VLSI circuits.

[0021] During operation, the image content data of the generated images is transmitted to the controller 80 from either the scanning system or via an online or workstation connection for processing and generating print head control signals output to the print head modules 34A-34D. Along with the image content data, the controller receives print job parameters that identify the weight of the medium, the dimensions of the medium, the printing speed, the type of medium, the ink coverage of the areas to be generated on each surface of each sheet, the position of the images to be generated on each surface of each sheet, the color of the medium, the orientation of the media fibers in fibrous media, the temperature and humidity of the printing zone, the water content of the medium, and the manufacturer of the medium. As used in this document, the term "print job parameters" refers to non-image content data for a print job, and the term "image content data" refers to digital data that identifies the ink images to be printed on the medium sheets.

[0022] Like reference numerals are used to identify like components, and FIG. 1 shows a high-speed color inkjet printer 10' in which a print head temperature adjustment module 36 is monitored and operated by a controller 80' to adjust the temperature of each piezoelectric print head of the printer. The piezoelectric print head 34A1 is configured to have a pair of modules 36 as shown in FIG. 2A, and a heat sink 216 of another module 36 associated with a central print head within the same print head module 34A (FIG. 6) is also shown in FIG. 2A. The print head can be configured as an integrated replaceable unit having a heat transfer member 212, a thermoelectric cooling device 220, and optionally a heat sink 216, or the heat transfer member, the cooling device, and optionally the heat sink can be attached to the print head in an existing printer as described. Such a modification of a known printer also requires the installation of a print head temperature sensor if the print head temperature sensor is not already provided in the printer for each print head, and additional program instructions stored in a member operably connected to the controller so that the controller can operate the temperature adjustment module as will be described in more detail below. In FIG. 1, the illustrated module 36 assists in adjusting the temperature of the print head closest to the observer in each of the print head modules 34A, 34B, 34C, and 34D. The module 36 is configured for use with a piezoelectric print head rather than a thermal inkjet print head because it is necessary to adjust the temperature of the piezoelectric inkjet print head within a narrow temperature range below its normal operating temperature, particularly during a duplex printing job using heavy stock, where each inkjet requires a higher degree of accuracy than a thermal print head that includes a heater.

[0023] A piezoelectric printing head 36A configured with a temperature adjustment module 36 is shown in more detail in FIG. 2A. In FIG. 2A, the module 36 is positioned on each side of the printing head 34A1 in the process direction. Each module includes a heat transfer member 212, a heat sink 216 shown as a set of heat fins, and a thermoelectric cooling device 220 interposed between the heat transfer member 212 and the heat fins 216. The heat transfer member 212 is made of a material having a high thermal conductivity such as copper (385 W / m·Kelvin degree) or aluminum (239 W / m·Kelvin degree). The heat fins 216 are also made of a relatively high heat transfer material such as aluminum (237 W / m·Kelvin degree). As used herein, the term "thermoelectric cooling device" means a device that conducts heat along a temperature gradient within the device in the direction of the current flowing across the device. The thermoelectric cooling device 220 is configured to have a plane corresponding to the plane in which the heat fins extend. In one embodiment, the thermoelectric cooling device is a semiconductor device including an N-doped region and a P-doped region configured to conduct heat in a direction corresponding to the direction of the current passing through the device. Such a device is generally known as a Peltier device and is commercially available. The controller 80' is configured to couple a current to the thermoelectric cooling device 220 in a direction such that the thermoelectric cooling device 220 can dissipate heat by directing heat from the heat transfer member 212 to the heat fins 216. Thus, the module 36 is configured to draw heat from the printing head 34A1 and cool the printing head.

[0024] As shown in FIG. 2A, a temperature sensor 224 is attached to the heat transfer member 212, and this sensor is operably connected to the controller 80'. The sensor 224 is configured to generate an electrical signal indicating the temperature of the member 212 corresponding to the temperature of the printing head. The controller 80' has a pair of temperature set points to be compared with the signal from the sensor 224, and is configured to determine what type of temperature adjustment is required to keep the printing head within the temperature range defined by the two set points, as will be described in more detail below.

[0025] In one embodiment, the temperature control module 36 is configured as a replaceable module that can be selectively attached to and removed from the print head. Such a module is shown in Figure 2B. The module 36 includes a bracket 240 to which a heat transfer member 212 is attached, and a thermoelectric cooler 220 is attached to the heat transfer member 212. In the illustrated embodiment, the bracket 240 is configured in a U-shape having two parallel sides 244A and 244B when viewed from the side. Each side 244A and 244B includes the heat transfer member 212 and the thermoelectric cooler 220, as shown in the figure. The two sides are configured with an opening between them corresponding to the width of the print head in the process direction and the length of the print head in the cross-process direction, such as the print head 36A. The bracket 240 can be placed over the print head before being installed in the print head module, as shown in the figure. Other configurations of the bracket are also possible, such as a rectangle with an opening corresponding to the shape and size of the print head, so that the print head can be inserted into the bracket and the components can be attached to the bracket. If desired, the heat sink 216, shown as a set of heat fins, can also be attached to the thermoelectric cooler 220 using a thermal adhesive similar to the adhesive used to attach the heat transfer member 212 to the bracket 240 and the adhesive used to attach the thermoelectric cooler 220 to member 212. An example of such an adhesive is Dow DOWSIL® 1-4174 TC thermal adhesive.

[0026] Next, the temperature control of the print head will be described with reference to Figure 3. The controller 80' is configured to have program instructions stored in a memory operably connected to the controller when the controller 80' performs the temperature control process described with reference to Figure 3. The controller 80' monitors the signal from the temperature sensor 224 and compares it to an upper threshold setpoint and a lower threshold setpoint of a predetermined temperature range. If the temperature indicated by the signal is below the lower threshold of the predetermined range, the controller operates a pulse width modulation (PWM) unit 228 operably connected to the print head heater 232. The duty cycle of the PWM signal generated by the unit 228 operates the print head heater to heat the print head. A 0% PWM signal turns the heater off, a 100% signal sets the heater to its maximum heat generation capacity, and between these values, the heater operates at a percentage corresponding to its maximum capacity. These types of heaters are known to ensure that the print head remains above the ambient temperature inside the printer. When the temperature signal indicates that the print head temperature is within the temperature range between two setpoints but is rising, controller 80' operates the PWM unit to reduce the heat generated by the print head heater 232. If the print head temperature exceeds the upper threshold specified by the larger of the two setpoints, controller 80' sets the duty cycle of the PWM unit to 0 and operates the current generator 236 to send current through the thermoelectric cooler 220. The thermoelectric cooler continues to operate until the temperature indicated by the sensor signal falls below the larger setpoint. Once the indicated temperature continues to fall, controller 80' turns off the current generator 236 and starts operating the PWM unit 228 to gradually turn on the heater 232 until the temperature begins to stabilize within the temperature range between the two setpoints. At that point, controller modifies the PWM signal duty cycle to keep the temperature within the temperature range.If the temperature falls outside this range, or if the temperature exceeds the upper temperature threshold, the controller activates the cooling device 220 to lower the temperature of the print head, or activates the PWM module to generate a PWM signal with a 100% duty cycle to heat the print head and return it to the temperature range between the set points. In one embodiment, the two set points are approximately 30°C to 32°C.

[0027] Figure 4 shows a flowchart of process 400, which adjusts the print head temperature using adjustment modules 36 located on each side of the print head in the process direction. Modules 36 operate to maintain the print head temperature within the printer within a predetermined temperature range. In the following discussion, references to process 400 performing a function or operation refer to the operation of a controller, such as controller 80', which performs a function or operation in relation to other components within the printer by executing stored program instructions. For illustrative purposes, process 400 is described as being performed using printer 10' in Figure 1.

[0028] The process 400 for operating the printer 10' begins with the operation of the PWM unit, which generates a 100% duty cycle signal to activate the print head heater and raise the print head temperature to the lower threshold of two setpoints (block 404). The controller then compares the temperature sensor signal with the two setpoint temperatures (block 408), and as long as the print head temperature is within the temperature range defined by the two setpoints, the PWM unit operates to adjust the PWM signal to keep the print head temperature within the temperature range (block 412). If the print head temperature signal indicates that the print head signal is outside the temperature range, it is determined whether the print head temperature has exceeded the upper threshold (block 416). If so, the PWM unit operates to generate a PWM signal with a 0 percent duty cycle, and the current generator operates to supply current to the thermoelectric cooler (block 420). This process (blocks 416 and 420) continues until the print head temperature no longer exceeds the upper threshold. The process stops the current generator and turns off the cooling system (block 424), and the process determines whether the print head temperature is below the lower temperature threshold (block 428). If so, the PWM unit is operated to generate a PWM signal with a 100% duty cycle (block 404), and the process continues. If the print head temperature is not above the upper threshold but above the lower threshold, the process verifies that the print head temperature is within the temperature range (block 408), and continues adjusting the PWM signal until the temperature is outside the temperature range.

[0029] It will be understood that various variations of the above-disclosed features and functions, or substitutes thereof, may be desirablely combined with many other different systems or applications. Various currently unforeseen substitutes, modifications, variations, or improvements, which are also intended to be covered by the following "Claims," ​​may be subsequently made by those skilled in the art.

Claims

1. An inkjet printer, a printhead configured to eject ink droplets; a sensor configured to generate a signal indicative of a temperature of the print head; a first thermoelectric cooling device configured to remove heat from the print head; a controller operably connected to the sensor and the first cooling device, a controller configured to operate the first cooling device to remove heat from the print head in response to the signal generated by the sensor indicating that the temperature of the print head is above a predetermined temperature set point.

2. a heat transfer member attached to the print head for conducting heat away from the print head; The inkjet printer of claim 1 , wherein the first thermoelectric cooling device is further configured to remove heat from the heat transfer member.

3. further comprising a current generator operably connected to the first thermoelectric cooling device; The controller is operably connected to the current generator, the controller comprising: The inkjet printer of claim 2 , further configured to operate the current generator to power the first thermoelectric cooling device.

4. 4. The inkjet printer of claim 3, wherein the thermoelectric cooling device is a Peltier cooling device.

5. 5. The inkjet printer of claim 4, further comprising a heat sink attached to said Peltier cooling device for dissipating heat from said Peltier cooling device.

6. 6. The ink jet printer according to claim 5, wherein the heat transfer member is made of copper.

7. 7. The inkjet printer of claim 6, wherein the heat sink is made of aluminum.

8. a second thermoelectric cooling device mounted on a side of the print head opposite the side of the print head on which the first thermoelectric cooling device is mounted; 8. The inkjet printer according to claim 7.

9. 1. A method of operating an inkjet printer, comprising: generating a signal indicative of a temperature of a printhead within said inkjet printer; comparing the generated signal to a predetermined temperature set point; operating a first thermoelectric cooling device to remove heat from the print head in response to the signal generated by the sensor indicating that the temperature of the print head is greater than the predetermined temperature set point; A method comprising:

10. conducting heat away from the print head using a heat transfer member; operating the first thermoelectric cooling device to remove heat from the heat transfer member; The method of claim 9 further comprising:

11. generating a current; and connecting the generated current to the first thermoelectric cooling device to operate the first thermoelectric cooling device; The method of claim 10 further comprising:

12. The method of claim 11 , wherein connecting the generated electrical current to the first thermoelectric cooling device comprises connecting the generated electrical current to a Peltier cooling device.

13. dissipating heat from the Peltier cooling device using a heat sink attached to the Peltier cooling device; The method of claim 12 further comprising:

14. The method of claim 13 , wherein the heat transfer member is made from copper.

15. The method of claim 14 , wherein the heat sink is made from aluminum.

16. cooling the print head with a second thermoelectric cooling device mounted on a side of the print head opposite the side of the print head on which the first thermoelectric cooling device is mounted; 16. The method of claim 15, further comprising:

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