Printers and methods to reduce vapor emissions in printers

Printers and methods to reduce vapor emissions in printers are disclosed. An example printer is described, including a fan to urge an airflow from a first printer portion, a duct to direct the airflow from the first printer portion and to substantially prevent adding air to the airflow, a condenser in communication with the duct, the condenser comprising a first condensing fin to condense oil in the airflow into a liquid, and an airflow reflection reducer associated with the condenser to reduce reflection of the airflow off of the first condenser fin.

BACKGROUND

Some printers and printing presses (hereinafter printers) use a condenser to remove heat and/or vapor(s) generated during operation. A condenser uses one or more temperature-controlled surfaces to affect the temperature of a fluid passing by the condenser. The fluid may then be re-circulated back into the printer to maintain an acceptable operating temperature of the printer.

DETAILED DESCRIPTION

Certain examples are shown in the above-identified figures and described in detail below. In describing these examples, like or identical reference numbers are used to identify the same or similar elements. Additionally, several examples have been described throughout this specification. Any features from any example may be included with, a replacement for, or otherwise combined with, other features from other examples. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic for clarity and/or conciseness. Although the following discloses example systems and apparatus, it should be noted that such systems and apparatus are merely illustrative and should not be considered as limiting the teachings of this disclosure.

The example systems and apparatus described herein may be used to increase collection and/or reduce emission of vapor in, for example, a printer such as a printing press. Some example apparatus described herein include a duct to direct a mixture of air and oil vapor from a printer to a condenser. An airflow reflection reducer couples the duct to the condenser. The reducer operates to reduce airflow reflection from the condenser to thereby improve the efficiency of the condensing process. The reducer also substantially reduces or prevents air from outside the duct and reducer from diluting the oil vapor in the mixture. Thus, the mixture has substantially the same concentration of oil vapor as when the mixture entered the duct from the printer. The example condenser then cools the mixture, causing at least a portion of the oil vapor within the mixture to condense into a liquid, which may then be collected. Collected oil may be recycled. Further, collecting the oil reduces the amount of oil vapor that may escape from the printer. Cooled air from the condenser is then re-circulated into the printer.

FIG. 1depicts an example airflow cycle for a large format printer or printing press100. The example printer100uses one or more inks that include a significant portion of oil. In some examples, the oil is a volatile organic compound (VOC) such as Isopar L. Emissions of many VOCs are regulated by government agencies and, thus, keeping emissions below regulation amounts is desirable. As the ink is transferred to an image transfer device102and to a print substrate104(e.g., paper), the oil vaporizes into the internal air of the printer100.

FIG. 2depicts the example image transfer device102ofFIG. 1in greater detail. The example transfer device102includes a transfer member202. The transfer member202, also known as a blanket, receives an image of ink from a drum204. The transfer member202rotates to apply the ink image to a print substrate104such as paper. As mentioned above, oil from the ink vaporizes into the air near the transfer member202. A hood206captures hot internal press air, including the vaporized oil, and urges (e.g., via a blower) the hot air away from the image transfer device102to be cleaned and/or re-circulated.

Returning toFIG. 1, a condenser106, which may be coupled to the hood206, cools hot air108from the image transfer device102and condenses a portion of the vaporized oil into liquid oil. The liquid oil is then collected for recycling. Cooled air110, including any remaining oil vapors, is re-circulated back from the condenser106into the printer100.

FIG. 3depicts a known condenser configuration300in a printer. In the illustrated configuration300ofFIG. 3, a condenser302cools air from a printer internal space and condenses oil vapor from the air. A first airflow304enters a printer. The first airflow304may include, for example, ambient air within the operating region of the internal printer airspace. A second airflow308, received from a second portion310of the printer100, includes oil vapor-laden air that may be directed from a portion of the press near the transfer member202.

In the illustrated condenser configuration300ofFIG. 3, the first and second airflows304and308mix in a chamber or cabinet312adjacent the condenser302. The oil density of the air mixture in the cabinet312is less than the oil density of the second airflow308because the first airflow304has a lower concentration of oil vapor than the second airflow. Thus, when the first and second airflows304and308mix, the oil vapor is diluted by the first airflow304.

The second airflow308is urged or blown at the condenser302(e.g., using a fan or blower). The condenser302includes a plurality of condensing fins314that cool passing air. A first portion318of the second airflow308passes through the condenser302, which cools and reduces the vapor density of the first portion316, and re-circulates through the printer100. A reflected air318portion of the second airflow308reflects off of the condensing fins314and back into the cabinet312. A second portion320of the air within the cabinet312also flows through the condenser302. The reflected air318, and the oil vapor contained therein, intermixes with the first airflow304within the cabinet312. Thus, the concentration of oil vapor flowing through the condenser302is less than the concentration of oil vapor in the second airflow308. Because the amount of oil vapor that condenses is based on the concentration of oil vapor in the mixture passing through the condenser302, the reflection and the mixture of the first and second airflows304and308reduces the oil that is condensed to liquid by the condenser302.

FIG. 4depicts an airflow cycle400for a known condenser configuration300in a large format printer or printing press. In the illustrated airflow cycle400, air and/or a mixture of air and oil vapor travels between a transfer member402(e.g., an intermediate transfer member, a blanket), an internal airspace of a printer (e.g., press internal airspace406), and a condenser assembly106. The condenser assembly106includes a condenser414and a condenser fan422. Additionally, air and/or oil vapor may be exchanged with an outside area410of the printer100via intake, exhaust, and/or leakage.

More specifically, an airflow404from the internal printer airspace412is urged toward the condenser414. Additionally, an air and/or oil vapor mixture406is directed from the internal printer airspace412to the transfer member402by transfer member fan(s)420. The transfer member402increases the oil vapor concentration of the received air due to vaporization of oil from the transfer member402. A second air and oil vapor mixture408is urged (e.g., via a fan, not shown) from the transfer member402to the condenser414. A portion of the second mixture408and the airflow404pass through the condenser414, or are drawn by the condenser fan(s)422, and mix. The air and oil vapor passing through the condenser408become a re-circulated airflow416that is re-circulated back into the internal printer airspace412. However, a second portion (e.g., reflected air418) of the second mixture408and the airflow404is reflected off of the condenser414and back into the internal printer airspace412. The reflected air418increases the oil vapor concentration within the internal printer airspace412.

The internal printer airspace412also exchanges air with the outside410of the printer100. For example, air and/or oil vapor may leak or escape from the internal printer airspace412. As the concentration of oil vapor in the internal printer airspace412increases, the amount of oil vapor that escapes from the printer100to the outside410increases. However, some types of oils (e.g., Isopar L) are considered VOCs, and leakage from the printer100is undesirable. As a result of the reflection of the reflected air418, the air in the internal printer airspace412has an increased oil vapor concentration, which increases the leakage of oil vapor from the printer100.

FIG. 5depicts an example airflow cycle500for an example large format printer or printing press506. As shown inFIG. 5, the printer506includes airflow reflection reducer(s)524. The example printer506also includes an internal airspace512, a transfer member502(e.g., a blanket), and a condenser assembly106associated with the reducer(s)524. The condenser assembly106includes a condenser514and a condenser fan522. The reducer(s)524function to reduce airflow reflections from the condenser assembly106. Additionally, the printer506includes one or more transfer member fans520. The transfer member fan520and the condenser fans522urge airflows through the airflow cycle500. The airflow cycle500includes a first airflow506from the printer internal airspace512to the transfer member502, a second airflow508from the transfer member502to the reducer524, an ambient airflow504from the printer internal airspace512to the condenser514, and a re-circulation airflow516from the condenser fan(s)522to the printer internal airspace512.

As mentioned above, the reducer(s)524reduce airflow reflection from the condenser514. Consequently, compared to the airflow cycle400ofFIG. 4and the known condenser configuration300ofFIG. 3, the airflow cycle500exhibits reduced and/or no reflection airflow. As a result, the second airflow508that has the oil vapor-laden air is more effectively transmitted through the condenser514and less oil vapor is reflected back to the printer internal airspace512. Thus, more oil vapor is collected at the condenser514as liquid, and less oil vapor is leaked to the outside of the printer510. In some examples, the transfer member502is included within the printer internal airspace512, thereby removing the airflow506as a distinct airflow.

FIG. 6is a front view of example airflow reflection reducers524aand524bcoupled to a condenser514. The reducers524aand524brespectively receive air and oil vapor mixtures via ducts as described in more detail below. In some examples, the reducers524aand524bare in communication with ducts from regions around a transfer member or blanket (e.g.,202ofFIG. 2). The reducers524aand524bsubstantially reduce or prevent reflections of air and oil vapor mixtures directed to the portions of the condenser514covered by the reducers524aand524b. The air and oil mixtures are directed via the ducts into the reducers524aand524b. In some examples, the condenser514is substantially completely covered by reducers524aand524b. In yet other examples, all or a portion of the condenser514is covered by a single reducer524athat receives an air/oil mixture via a single duct.

The condenser514includes a plurality of condensing fins602,604,606,608, and610. As illustrated inFIG. 6, the example condensing fins602-610are oriented in horizontal rows of parallel vertical fins. The condensing fins602-610may additionally or alternatively be arranged horizontally in columns. Other orientations may also be used. Whether accomplished via orientation or geometry, increasing the total surface area for the condensing fins602-610increases the oil vapor collected by the condenser514. In some examples, the reducers524aand524bdefine internal spaces. In such examples, the condensing fins608and610within the reducers524aand524bmay extend into the internal spaces within the reducers524aand524bto increase the surface area exposed to the air and oil vapor mixture(s), thereby increasing the liquid oil collected.

In general, the reducers524aand524bare attached to the condenser514to increase a proportion of air and oil mixture from the duct inlet604that flows through the condenser514and to decrease or eliminate a proportion of the air and oil mixture from the duct inlet604that escapes without flowing through the condenser514. In particular, the example reducer524aincludes a cover612and a duct inlet614. The example cover612is a rectangular-shaped box having one face open to the condenser514and at least a portion of another face open to the duct inlet614. The sides of the cover612are pressed or fit to the condenser fins608such that airflow is restricted or prevented between the space within the cover612and the space outside the cover612. The example duct inlet614extends from the cover612opposite the condenser514and includes a seal616. The seal616receives a first duct and substantially seals air from outside the reducer524afrom mixing with the air and oil mixture entering a receptacle or opening618. The receptacle618substantially aligns with a corresponding opening in the first duct coupled to the duct inlet614and receives an air and oil mixture from the first duct. The example reducer524bis similar to the reducer524a, but has a differently-shaped cover620, duct inlet622, and seal624. The reducer524bis also pressed or fit to the condenser fins610so that airflow between the inside and the outside of the reducer524bis limited. The seal624receives a second duct and substantially seals air from outside the reducer524bfrom mixing with the air and oil mixture entering a receptacle or opening626in the duct inlet622. By preventing additional air from diluting the oil vapor, the reducers524aand524band duct(s) substantially preserve the concentration of oil vapor in the mixture and increase condensation of the oil vapor.

As an air and oil mixture enters the example duct inlet614on the reducer524a, the mixture is urged toward the condenser fins508. As illustrated with reference to the known condenser configuration300ofFIG. 3, a portion of the mixture may initially reflect off of the condenser fins508. However, the cover612facilitates redirection of reflected airflow toward the condenser514. Thus, in contrast to the known condenser configuration300, any reflected mixture is confined to and may only disperse within the cover612of the reducer524a. Continued flow of air and oil mixture into the duct inlet614of the reducer524areduces or prevents reflected mixture from exiting via the duct inlet614. Therefore, any reflected mixture is forced back at the condenser514and flows through the condenser fins608covered by the reducer524a, where the mixture is cooled and oil vapor is condensed into liquid.

The example condenser514also includes one or more condenser fins602,604, and606that are not enclosed or covered by the reducers524aand524b. Instead, the condenser fins602-606allow air from the internal printer airspace512and/or a chamber or cabinet outside of the reducers524aand524bto pass through the condenser514(e.g., to control the temperature of the printer).

FIG. 7is a profile view of one of the example reducers524acoupled to the condenser514ofFIG. 6. As discussed above, the example reducer524aincludes a cover612and a duct inlet614. The duct inlet614is sealingly coupled to a duct as described in more detail below. The duct inlet614receives an air and oil vapor mixture via the duct and directs the air into the cover612and toward the condenser514, while preventing additional air from outside of the reducer524a(e.g., a chamber or cabinet) from intermixing with and/or diluting the mixture.

FIG. 8is a profile view of an example duct and reducer configuration800to reduce an airflow reflection off of a condenser514. The example configuration800illustrates a duct802coupled to a reducer524a. The reducer524aincludes a cover612and a duct inlet614including a seal616. The duct802is coupled to the seal616, which substantially reduces or prevents intermixing of air and oil vapor mixture808within the duct802and/or the reducer524awith ambient air in a chamber or cabinet airspace804outside the duct802. The cover612and the condenser514also define a volume806between the cover612and the condenser514.

The duct802directs an air and oil vapor mixture808from, for example, a transfer member of an imaging or printing device (e.g., the printer100ofFIG. 1). The mixture808is urged through the duct802and the duct inlet614into the cover612of the airflow reflection reducer524a. The mixture808disperses to fill the volume806between the cover612and the condenser514. The cover612is sealed to a portion of the condenser514to prevent ambient air from the cabinet804from entering the cover612around one or more condenser fins602aand602bon the condenser514, thereby preventing intermixing and/or dilution of the air and oil vapor mixture808within the cover612.

The mixture808passes through the condenser514by passing around the condensing fins602aand602bon the condenser514. The condensing fins602aand602bare kept at a relatively cold temperature. The condensing fins602aand602bcool the passing mixture808, which causes the oil vapor in the mixture808to condense into liquid oil810. The liquid oil810may then drip into a collecting pan812for collection and/or recycling. As the temperature of the condensing fins602aand602bdecreases, more oil vapor condenses into liquid and less oil vapor is re-circulated into the press internal airspace. In some examples, the condensing fins602aand602bare cooled to less than about 6 degrees Celsius. In some such examples, the condensing fins602aand602bmay be cooled to 1 degree Celsius or less. However, if the temperature of the condensing fins602aand602bis 0 degrees Celsius or less, water vapor in the mixture808may condense and freeze onto the condensing fins602aand602b, which may then reduce the effectiveness of the condensing fins by reducing heat transfer.

FIG. 9is a top view of the example duct and reducer configuration800ofFIG. 8. As described above, the duct802is coupled to the duct inlet614via the seal616. The duct802directs the air and oil vapor mixture808to the duct inlet614and into the cover612of the airflow reflection reducer524a. Within the cover612, the mixture808disperses and passes through the condenser514. An outside area902of the condenser514allows ambient air904within the cabinet804to pass through the condenser514. The condenser fins602aand602bcool the ambient air904that passes through the condenser514. After flowing through the condenser514, cooled ambient air906and re-circulated mixture908combine and re-circulate to the printer. Thus, while mixing ambient air with the oil vapor mixture is avoided on the input side of the condenser514, it is permitted downstream of the condenser514.

FIG. 10is a front view of example airflow reflection reducers524aand524bcoupled to a condenser514. In this example, the condenser514is substantially covered by the reducers524aand524b. The reducer524aincludes a cover612and a duct inlet614. The duct inlet614may be coupled to a first duct to direct a first air and oil vapor mixture through the condenser514. Similarly, the reducer524bincludes a cover620and a duct inlet622. The duct inlet622may be coupled to a second duct to direct a second air and oil vapor mixture through the condenser514. In the example ofFIG. 10, substantially less ambient air (as compared toFIG. 6) passes through the condenser514because the reducers524aand524bcover all or substantially all of the condenser fins602-610of the condenser514. By contrast, inFIG. 6, portions602,604, and606of the condenser514are not covered by the reducers524aand524b.

FIG. 11is a top view of an example duct and reducer configuration1100where a reducer524aand a condenser514engage and disengage a duct1102based on a hinged movement1104. In the illustrated configuration1100, the condenser514is coupled to a hinge1106, which permits the hinged movement1104of the condenser514and the attached reducer524a. For example, the condenser514may be attached to a door that may be opened to provide access to a cabinet area1108. When the door is opened as illustrated inFIG. 11, the reducer524adecouples from the duct1102. When the door is closed, a seal616on the reducer524acouples the reducer524ato the duct1102to reduce or prevent additional air from diluting oil vapor inside of the duct1102and/or the reducer524aas described above.

FIG. 12is an isometric view of another example duct and reducer configuration1200. The example configuration1200includes a condenser514, a reducer524a, and a duct1202. The reducer524aand the duct1202are shown uncoupled inFIG. 12to illustrate the respective configurations of each. The duct1202and a seal616on the reducer524aare sized and shaped such that an outlet face1204of the duct1202fits into the seal616.

The examples described herein may be adapted to use many different geometries. For instance, while the example covers612and620illustrated inFIGS. 6-12are rectangular in geometry, other geometries may be used to implement the example reducers524. In the illustrated examples, the rectangular covers612and620may be easily fit to the condenser fins602-610in vertical and/or horizontal rows to reduce and/or prevent airflow between the inside and outside of the reducers524. Additionally, other geometries may be used to implement the duct inlets614and622and/or the seals616and622. For example, the duct inlets614and662and/or the seals616and622may have a cylindrical or other geometry to be coupled to a duct having a circular opening. The configurations of the covers612and620may be based on the level of communication between different portions of the condenser514. For example, the covers612and620illustrated inFIG. 6may be appropriate for condenser fins602-610that extend from the top to the bottom of the condenser514.

FIG. 13is a graph1300depicting an example relationship curve1302between condensing fin temperature and condensation rate of Isopar L from an airflow. If the vapor density of an airflow at a particular temperature is higher than the curve1302at that temperature, the vapor in the airflow will condense until the vapor density approaches that of the curve1302at the given temperature. Thus, as illustrated inFIG. 13, a lower temperature will cause more condensation for a given vapor density in an airflow.

An example vapor density1304is also shown, which illustrates the vapor density in an example printer. At a condensing fin temperature of 6 degrees Celsius, a first amount1306of vapor will condense into liquid given sufficient time and interaction. At a lower condensing fin temperature of 1 degree Celsius, a second, larger amount1308of vapor will condense into a liquid given sufficient time and interaction.

While the temperature of the condensing fins determines the lower temperature to which the mixture passing the condensing fins cools, the length of time that a mixture is exposed to the condensing fins affects the mixture temperature in its approach toward the condensing fin temperature. The exposure time may thus be increased by increasing the length or surface area of the condensing fins.

FIG. 14depicts a comparison of example Isopar condensation rates between the known condenser configuration400ofFIG. 4and the example condenser configurations described herein. A first condensation rate1402illustrates a measured condensation rate of oil vapor from an air and oil vapor mixture using the known condenser configuration400. A second condensation rate1404illustrates a measured condensation rate of oil vapor from an air and oil vapor mixture using the example reducers524aand524bofFIG. 6. As illustrated inFIG. 14, the condensation rate is increased by approximately 16%. Thus, the rate of Isopar L that is not captured is reduced from 0.34 g/s to 0.27 g/s, for approximately a 21% reduction.

FIG. 15depicts example Isopar concentration measurements of an example printer using the known condenser configuration400ofFIG. 4and the example condenser configurations described herein. The first four measurements1502,1504,1506, and1508represent the measured concentrations at different points in an internal printer airspace using the example reducers524aand524bofFIG. 6. The last four measurements1510,1512,1514, and1516represent the measured concentrations at substantially the same points in the printer airspace using the known condenser configuration400ofFIG. 4. As shown inFIG. 15, the measurements1510-1516have a higher concentration of Isopar L. As described above, the higher concentration of oil vapor within the reducers524aand524bcauses more oil vapor to condense into liquid, thereby lowering the amount of oil vapor that is re-circulated to the printer.

Although certain methods, apparatus, and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. To the contrary, this patent covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.