WO2024043895A1

WO2024043895A1 - Toner compositions having a color space characteristic for monochrome printing

Info

Publication number: WO2024043895A1
Application number: PCT/US2022/041588
Authority: WO
Inventors: Elizabeth SWANSON; Gabriel Scott MCDANIEL; Jinmo HONG; Travis Moats; Kram ALLEN; Douglas Richards
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2022-08-25
Filing date: 2022-08-25
Publication date: 2024-02-29

Abstract

An example toner composition includes an aggregate of a plurality of toners, each of the plurality of toners being a different color, wherein the aggregate has a color space characteristic to perform monochrome printing.

Description

TONER COMPOSITIONS HAVING A COLOR SPACE CHARACTERISTIC FOR MONOCHROME PRINTING

BACKGROUND

[0001] An image forming apparatus may perform an electrophotographic printing process using toner that is supplied from a replaceable toner cartridge. The toner cartridge may be originally supplied with a certain volume of toner and may remain in the image forming apparatus until the volume of toner is exhausted. At that time, the toner cartridge may be replaced. In some cases, the toner cartridge may be replaced before the volume of toner is exhausted. That is, the toner cartridge may be replaced while an amount of unused or undeveloped toner remains within the toner cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Various examples will be described below by referring to the following figures.

[0003] FIGS. 1A and 1 B illustrate a color space to describe various examples;

[0004] FIG. 2 illustrates various examples of color space boundaries that may be applied to a toner composition;

[0005] FIG. 3 illustrates a selected color space boundary and characteristics of toner compositions over an expected lifetime according to an example;

[0006] FIG. 4 is a graph illustrating L* values and halftone values of an example toner composition and a reference black toner; and

[0007] FIG. 5 illustrates a method for providing a toner composition according to an example; and

[0008] FIG. 6 illustrates a cartridge refill kit according to an example. DETAILED DESCRIPTION

[0009] Hereinafter, various examples will be described with reference to the drawings to assist in an understanding of the disclosure. However, the disclosure may be modified and performed variously unlike in the examples described herein. Like reference numerals in the specification and the drawings denote like elements, and thus a redundant description may be omitted.

[0010] The terms used in the specification and claims have been selected as general terms in consideration of functions in the disclosure. However, these terms may vary in accordance with precedent, technical interpretation, the emergence of new technologies, and the like.

[0011] In the disclosure, an expression that a certain component is “connected” to another component includes a case in which the components are “directly connected to each other,” and also a case in which the components are “connected to each other with another component interposed therebetween.” In addition, a component that is described to “include” another component, may include still another component, rather than excluding it, unless otherwise noted. [0012] An image forming apparatus such as a printer, a copier, a scanner, a fax machine, or a multi-purpose peripheral (MFP) that complexly implements functions of the printer, the copier, the scanner, and the fax machine through one apparatus, may use a toner cartridge as a replaceable component. For example, an image forming apparatus may perform an image forming operation based on an electrophotographic printing process in which a latent image formed on a photoconductor is used to form a toner image by application of toner to the latent image. In that case, the image forming apparatus may include the toner cartridge to supply the toner.

[0013] The toner cartridge may be manufactured and/or supplied by a manufacturer or other supplier and may contain a certain volume of toner. For example, the toner cartridge may be supplied having a volume of toner to support a certain number of image forming operations. Based on continued use of the toner cartridge, the toner supply of the toner cartridge may become exhausted. In that case, the toner cartridge may be removed from the image forming apparatus and replaced with another toner cartridge. In that situation, an amount of unused or undeveloped toner in the toner cartridge may be at or near zero and a user of the toner cartridge may dispose of the toner cartridge, such as by returning the toner cartridge to the manufacturer, supplier, etc. for recycling.

[0014] However, in various situations, a toner cartridge may be removed from the image forming apparatus before the amount of unused or undeveloped toner in the toner cartridge is at or near zero. For example, the toner cartridge may suffer a defect, an error, or another problem that prevents the toner cartridge from use in the image forming apparatus. In another example, a user may return the toner cartridge before the amount of unused or undeveloped toner in the toner cartridge is exhausted based on the toner cartridge being part of a subscription program. In these and similar cases, the toner cartridge may still contain unused or undeveloped toner. In previous implementations, the toner cartridge that still contains unused or undeveloped toner may be disposed of in a similar manner as a toner cartridge having an amount of unused or undeveloped toner being at or near zero, such as by returning the toner cartridge to the manufacturer for recycling. In that case, the unused or undeveloped toner may simply be disposed of.

[0015] In examples that are described herein, unused or undeveloped toner may be gathered or harvested for use in a toner composition that supports monochrome printing. In various examples, the unused or undeveloped toner may be harvested from a used toner cartridge and may be harvested from a used toner cartridge of any color. In other examples, a source of the harvested toner may include toner that is located within a toner cartridge that has not been installed or used in an image forming apparatus or may refer to toner that has not been included in toner cartridge. For example, a toner cartridge that has not been installed or used in an image forming apparatus may be recalled or otherwise returned to a manufacturer. In that case, the recalled or otherwise returned toner cartridge may contain “unused” or “undeveloped” toner although the toner cartridge has not been installed or used in an image forming apparatus. As another example, use of a toner may be discontinued such that an inventory of bulk toner that has not been included in a toner cartridge may result. In that case, the bulk toner may be considered “unused” or “undeveloped” toner that may be harvested for purposes of the description herein.

[0016] In the following description, a used toner cartridge may be described as including “unused” or “undeveloped” toner, which refers to toner that is located within the used toner cartridge after installation and use of the toner cartridge in an image forming apparatus. In an example, the “unused” or “undeveloped” toner may be found within a supply reservoir of the used toner cartridge, which is distinct from used toner that may be found within a waste toner reservoir of the used toner cartridge.

[0017] In the following examples, harvested toner of any color may be aggregated with harvested toner of another color to create a toner composition and the toner composition may be used for draft quality printing, and more specifically draft quality monochrome printing. For example, the toner composition may be used in place of a black toner. In an example, the toner composition may be included in a toner cartridge and used in place of a black toner cartridge in an image forming apparatus that supports a color printing operation.

[0018] Draft quality printing generally refers to a printing operation that is performed at a lower level of quality than a standard printing operation for a given image forming apparatus or a given image forming operation. As used herein, draft quality printing refers to a printing operation using an example toner composition in place of a black toner, wherein the toner composition may have a color space characteristic that provides a lower print quality than a black toner. Advantages of using the toner composition despite the lower print quality may include a lower cost of the toner composition as compared to a cost of the black toner and that use of the toner composition reduces waste and supports sustainability by repurposing the unused toner.

[0019] In various examples as described herein, a color space characteristic of the toner composition may be selected to support use of the toner composition for draft quality printing. Moreover, the color space characteristic may be selected to support draft quality printing for an expected lifetime of the toner cartridge. [0020] FIGS. 1A and 1 B illustrate a color space to describe various examples.

[0021] Referring to FIGS. 1 A and 1 B, a color space 101 is a CIELAB color space that is defined by the International Commission on Illumination (CIE). The color space 101 may also be referred to as L*a*b* color space.

[0022] The L*a*b* color space expresses color using values of L*, a* and b* in which the L* value is used to represent a perceived color in terms of lightness (i.e. , a range from black to white), and the a* and b* values are used to represent the perceived color in terms of red, green, blue, and yellow. As illustrated in FIG. 1A, the vertical axis of the color space 101 represents the L* axis for lightness and has a value ranging from 0 (black) to 100 (white). The horizontal plane includes an a* axis that spans between -a (green) and +a (red) and a b* axis that spans between -b (blue) and +b (yellow).

[0023] FIG. 1 B illustrates the horizontal plane including the a* and b* axes in two dimensions, wherein the L* axis is presumed to flow into and out of the figure. The values of a* may range from -100 to +100 and similarly the values of b* may range from -100 to +100. As can be seen in FIG. 1 B, an a* value of -100 corresponds to green and an a* value of +100 corresponds to red. Also, a b* value of -100 corresponds to blue while a b* value of +100 corresponds to yellow. Thus, any perceived color may be assigned a value using the L*a*b* color space 101. As is evident from FIGS. 1 A and 1 B, a color having each of an a* value and a b* value at or near 0 corresponds to a color between black and white, depending on the L* value of the color as defined by the L* axis. In other words, the further a color moves away from the L* axis, the greater the color shift from the black/white L* axis.

[0024] Examples of the disclosure establish a boundary within the color space 101 for a toner composition that is to support draft quality printing and more specifically to support draft quality monochrome printing. That is, a boundary within the color space 101 may be established to define an acceptable range of color shift from the L* axis that is suitable for draft quality monochrome printing. In various examples, a boundary may be centered around the L* axis and have a perimeter corresponding to a color shift that is acceptable for draft quality printing. In more detail, examples of the disclosure establish a boundary within the color space 101 and apply the boundary to start and end points of the aggregated toner as well as a path between the start and end points over a lifetime of the toner composition.

[0025] FIG. 2 illustrates various examples of color space boundaries that may be applied to a toner composition.

[0026] Referring to FIG. 2, a color space 201 illustrates an exploded view of the a* and b* plane of the color space 101 of FIG. 1 B. As illustrated in FIG. 2, any of various boundaries may be established in the a*/b* plane for a toner composition. For example, a first boundary 210 is illustrated as a circle having a center on the L* axis and a given radius. A second boundary 220 is illustrated as a diamond having vertices at -10 and +10 on the a* axis and -10 and +10 on the b* axis. A third boundary 230 is illustrated as a box that is defined by sides located at -10 and +10 on the a* axis and -10 and +10 on the b* axis.

[0027] It is to be understood that the shapes and dimensions of the boundaries illustrated in FIG. 2 are merely examples and a boundary may be selected having any shape and/or dimension. For example, a boundary may have a shape of a square, a rectangle, a polygon, an ellipse, a diamond, a circle, or the like. In other examples, a boundary may not have a defined shape but may be any pattern having a continuous boundary surrounding the L* axis and selected based on an acceptable color of a toner composition to be used for draft quality printing. For example, a toner composition having a color value on the b* axis that is shifted toward -b* (i.e. , blue) from the L* axis by a first distance may have less effect on an acceptable color of the toner composition than a color value that is shifted toward +b* (i.e., yellow) from the L* axis by the same first distance. In that case, the dimensions (e.g., radius, distance, etc.) of the boundary with respect to the L* axis may not be consistent.

[0028] In the example of FIG. 2, an acceptable variance in color from the L* axis becomes greater in comparing the first boundary 210, the second boundary 220, and the third boundary 230. For example, the first boundary 210 having the shape of a circle that is centered around the L* axis limits an acceptable color space characteristic of the toner composition to a location within a radius of the circle. The second boundary 220 limits an acceptable color space characteristic of the toner composition to a location within the diamond shape, wherein the diamond shape of the second boundary 220 covers a greater area on the a*/b* plane than does the circle shape of the first boundary 210. Moreover, with regard to the first boundary 210 and the second boundary 220, the acceptable color on the a* or the b* axis may change based on the color on the b* or the a* axis. For example, in the second boundary 220, a color having a value of +10 on the a* axis limits an acceptable color value on the b* axis to be 0. In the example of the third boundary 230, an acceptable color value on either the a* or the b* axis may not be affected by a color value on the b* or the a* axis.

[0029] As explained above, a color space boundary for a toner composition may be selected to have any of a plurality of shapes and dimensions, depending for example, on an acceptable range of color values for draft quality monochrome printing. Thus, depending on variables such as an available amount of different colors of harvested toner, a type (e.g., model type, a manufacturer, an age, etc.) of each color of harvested toner, and the like, the toner composition may include a variety of ratios of different colors. Table 1 illustrates examples of toner compositions.

[0030] In Table 1 , seven example toner compositions are listed in which each example has a certain ratio of harvested toner of different colors and a certain color space value, specifically certain L* a* and b* values. The toner composition examples of Table 1 were tested to identify L* a* and b* values.

TABLE 1

[0031] Considering the examples of Table 1 in comparison to the various examples of color boundaries in FIG. 2, it can be seen that certain of the examples in Table 1 may be suitable for draft quality printing while other examples may not, depending on the selected color boundary. For example, based on the example boundaries 210, 220, and 230, the toner composition of example 6 would not be acceptable for draft quality printing at least because the b* value of example 6 lies outside the limits of each of boundaries 210, 220, and 230. On the other hand, the toner composition of example 2 would be acceptable for draft quality printing based on the a* and b* values lying within the limits of each of boundaries 210, 220, and 230. Of course, depending on the parameters of the selected color boundary, any of the examples of Table 1 may be available for draft quality printing. [0032] Table 1 lists the color ratios and L*, a* and b* values of the seven examples as tested at a certain time, for example at a time closely following a time at which each example was aggregated (e.g., mixed). And although a certain example may satisfy a selected color space boundary, the color space value of the example may shift over time. For example, a toner cartridge including the toner composition may be used in place of a black toner cartridge in an image forming apparatus and supply the aggregated toner for draft quality printing. However, based on an amount of toner composition used in the printing operations of an image forming apparatus, the color space value of the toner composition may change. Therefore, the toner composition should be tested over an expected lifetime of the toner composition to ensure that the color space characteristic of the toner composition remains within the selected color space boundary for the lifetime of the toner.

[0033] FIG. 3 illustrates a selected color space boundary and characteristics of toner compositions over an expected lifetime according to an example.

[0034] Referring to FIG. 3, a color space 301 illustrates an exploded view of the a* and b* plane of the color space 101 of FIG. 1 B. In the example of FIG. 3, a color space boundary 310 has been selected for a toner composition to provide a desired range of draft quality printing. The color space boundary 310 differs from the examples of FIG. 2 in that the color space boundary 310 does not have a certain shape such as a circle, a diamond, a square, etc. but has been selected to correspond to certain values to support an acceptable color range for draft quality printing.

[0035] In the example of FIG. 3, the color space values of three example toner compositions are shown over an expected lifetime of each toner composition. For example, a toner composition may be evaluated based on a certain number of test pages being printed using the toner composition. That is, the toner composition may be tested to identify an L* an a* and a b* value of the toner composition after printing a certain number of test pages. For example, a toner composition may be initially tested to identify an L* an a* and a b* value of the toner composition and may be repeatedly tested again after a certain number of pages are printed using the toner composition. In an example, a toner composition may be initially tested after a mixing process to aggregate the harvested toners comprising the toner composition is completed and may be tested again at intervals of 50 printed pages. Of course, the interval of 50 printed pages is an example and the interval may vary.

[0036] A first trace 320 corresponds to a first example toner composition and includes a first end point of a color space characteristic that lies within the color space boundary 310. That is, the L*, a* and b* values of the first example toner composition lie within the color space boundary 310. However, over an expected lifetime of the first example toner composition, the color space characteristic of the first example toner composition eventually lies outside of the color space boundary 310. Accordingly, because the color space characteristic of the first example toner composition has shifted outside of the color space boundary 310, the first example toner composition is not suitable for draft quality printing over the lifetime of the first example toner composition.

[0037] A second trace 330 corresponds to a second example toner composition and includes a first end point and a second end point of a color space characteristic that each lies within the color space boundary 310. That is, the L* a* and b* values of the second example toner composition lie within the color space boundary 310 at both end points of the testing period. However, over an expected lifetime of the second example toner composition, the color space characteristic of the second example toner composition has fallen outside of the color space boundary 310. Accordingly, because the color space characteristic of the second example toner composition has shifted outside of the color space boundary 310, and despite the fact that the color space characteristic has eventually returned within the color space boundary 310, the second example toner composition is not suitable for draft quality printing over the lifetime of the second example toner composition.

[0038] A third trace 340 corresponds to a third example toner composition that was tested at intervals of 50 printed pages. The third trace 340 includes a first end point and a second end point of a color space characteristic that each lies within the color space boundary 310. That is, the L* a* and b* values of the third example toner composition lie within the color space boundary 310 at both end points of the testing period. Moreover, each test result between the first and second end points also lies within the color space boundary 310. That is, all L* a* and b* values of the third example toner composition lie within the color space boundary 310 during the testing period. Accordingly, the third example toner composition may be considered acceptable for draft quality printing.

[0039] In an example, based on the color space characteristic of the first example toner composition falling outside of the color space boundary 310, the ratio of harvested toners of different colors that comprise the first example toner composition may be changed. For example, in a case in which the first example toner composition initially comprises 25% each of cyan, magenta, yellow, and black harvested toner, a percentage of at least one of the harvested toners may be increased and the updated toner composition be tested again. Similar changes may be made to the second example toner composition and the second example toner composition be tested again based on the updated ratio.

[0040] It should be understood that the first, the second, and the third examples of aggregated toner as described in FIG. 3 are not meant to correspond to the examples of Table 1 . Rather, the labels used in describing FIG. 3 are merely for convenience. [0041] As described above, a toner composition that is to be used for draft quality printing may replace a black toner in an image forming apparatus capable of color printing. In that case, an L* color space value of the toner composition should be able to support grayscale printing. That is, a toner composition should provide a sufficient range of L* color space values to support grayscale printing.

[0042] In an example, a toner composition having an L* color space value of < 65 at 100% halftone and an L* color space value of < 90 at 25% halftone may be considered to support grayscale printing. Moreover, a toner composition having a linear relationship between the L* color space values of 65 and 90 as the halftone values change may provide for visual distinction at lower halftone values and support draft quality printing. In an example, a toner composition having a linear range of L* color space values at halftones ranging from 25% and 100% may be considered to support draft quality printing.

[0043] FIG. 4 is a graph illustrating L* values and halftone values of an example toner composition and a reference black toner.

[0044] Referring to FIG. 4, a graph 401 is provided to illustrate a relationship between L* color space values and halftone values of an example toner composition and of a reference black toner. In the example of FIG. 4, a trace 410 illustrates a relationship between L* color space values and halftone values for the reference black toner and a trace 420 illustrates a relationship between L* color space values and halftone values for the example toner composition.

[0045] In more detail, the reference black toner was tested to identify L* color space values for halftone values of 25% and 100% and various halftone values between 25% and 100%. As illustrated in FIG. 4, a halftone value of 100% for the reference black toner corresponds to an L* color space value of approximately 25, while a 25% halftone value for the reference black toner corresponds to an L* color space value of approximately 75. Moreover, as seen by the trace 410, a substantially linear relationship exists between the 100% and 25% halftone values.

[0046] In an example, the L* color space values as well as the linear relationship of halftone values of the reference black toner may be used as a basis to identify whether a toner composition is able to provide draft quality monochrome printing. For example, a range of L* color space values for a toner composition may be selected based on the L* color space values of 25 and 75 that were determined for the reference black toner. In an example, because the aggregated toner is to be used for draft quality printing, the L* color space values based on halftone values of 100% and 25% may be respectively set as < 65 and < 90 in order to support draft quality printing. Also, a linear relationship of L* color space values to halftone percentage values may be set in order to support draft quality printing.

[0047] The trace 420 illustrates a test result of an example toner composition. As can be seen in FIG. 4, a halftone value of 100% for the example toner composition corresponds to an L* color space value of approximately 45, while a 25% halftone value for the example toner composition corresponds to an L* color space value of approximately 85. Moreover, as seen by the trace 420, a linear relationship exists between the 100% and 25% halftone values. Accordingly, in an example in which the L* color space values to support draft quality printing are set to be < 65 and < 90, the example toner composition in FIG. 4 would be determined to support draft quality printing as the L* color space values satisfy these set values and because the L* color space values provide a linear relationship between the halftone values.

[0048] FIG. 5 illustrates a method for providing a toner composition according to an example.

[0049] Referring to FIG. 5, unused or undeveloped toner may be harvested in operation 501 . As an example, a manufacturer or supplier may receive a used toner cartridge and identify that the used toner cartridge contains unused or undeveloped toner. In other examples, toner may be harvested from unused toner cartridges, from bulk toner that is discontinued, and the like. In various examples, the harvested toner may be separated based on a color, a type, a manufacturer, an age, and the like and the harvested toner may undergo various operations such as filtering, testing for electrophotographic or other properties, and the like. [0050] In operation 503, the harvested toner may be aggregated to obtain a homogenized toner composition. For example, a ratio of harvested toner of different colors may be selected and the selected harvested toners combined (e.g., mixed) to form the toner composition. As illustrated in Table 1 , the toner composition may include an aggregate of any of several different ratios of harvested toner of different colors. Considering the example of Table 1 , the toner composition may include harvested toner of cyan (C), magenta (M), yellow (Y), and/or black (K) and may include any of various ratios of the different colors such as 30% each of C, M, and Y and 10% K, 25% each of C, M, Y, and K, 33% each of C, M, and K, 25% each of two of C, M, and K and 50% of the remaining color, and the like. In various examples, the ratio of harvested toner colors may include less than or equal to 50% of black toner, a composite of at least 50% or more of C, M, and Y in combination, and the like.

[0051] In operation 505, a color space boundary may be selected. As an example, a color space boundary may be selected to limit an acceptable color shift of the toner composition from the L* axis. In an example, a color space boundary may be selected based on a desired level of draft quality printing, for example, a desired level of draft quality monochrome printing. In various examples, operations 503 and 505 may be performed in a different order than that illustrated in FIG. 5, or may be performed at the same time.

[0052] In operation 507, the toner composition may be tested to identify a color space value. For example, the toner composition may be tested to identify an L* an a*, and a b* value of the toner composition. Furthermore, the toner composition may be tested a plurality of times, such as based on a selected number of printing operations using the toner composition. For example, the color space values of the toner composition may be determined after completing 50 print operations using the toner composition.

[0053] In operation 509, a determination is made as to whether all of the tested color space values of the toner composition lie within the color space boundary selected in operation 505. For example, it may be determined in operation 509 whether the toner composition will support draft quality printing for an expected lifetime of a toner cartridge that includes the toner composition and that is used in place of a black toner cartridge in an image forming apparatus.

[0054] Based on determining in operation 509 that all of the test value are within the color space boundary selected in operation 505, the toner composition may be tested to identify whether grayscale printing is supported by the toner composition in operation 511. For example, as illustrated in the example of FIG. 4, the toner composition may be tested to identify whether L* color space values for the toner composition corresponding to 100% and 25% halftone are within a selected range. As an example, it may be determined whether the toner composition has an L* color space value of < 65 at 100% halftone and an L* color space value of < 90 at 25% halftone. It may also be determined whether there is a linear relationship of L* color space values at halftones ranging from 100% to 25% to support draft quality monochrome printing.

[0055] Based on determining in operation 509 that all of the test values are not within the color space boundary or based on determining in operation 511 that the toner composition does not support grayscale printing, a color ratio of the harvested toners may be changed in operation 513. For example, based on determining in operation 509 that all test values are not within the color space boundary selected in operation 505, a ratio of at least one color of the harvested toners may be increased. In that case, the process may return to operation 507 and subsequent operations such that the aggregated toner is tested again. Similarly, based on determining in operation 511 that the toner composition does not support grayscale printing, at least one of the harvested toners may be increased and the process may return to operation 507 and subsequent operations such that the aggregated toner is tested again.

[0056] Based on determining in operation 511 that the toner composition does support grayscale printing, the toner composition may be used for draft quality printing in operation 515. Furthermore, results of the aggregation and testing process, such as toner types and color ratios that were successfully tested to stay within the selected color boundary, may be saved for future use. For example, various data of the harvested toner, such as a type, a manufacturer, a color, etc., as well as ratios of certain toners that were successfully tested may be catalogued. As a result, the catalogued data may be used to aggregate a toner composition based on the same composition having previously resulted in successful testing.

[0057] In various examples, a toner composition obtained using the method of FIG. 5 may be included in a new toner cartridge. The new toner cartridge including the toner composition may be provided to a user for use in place of a black toner cartridge to support draft quality monochrome printing in an image forming apparatus supporting a color printing operation. In that case, the new toner cartridge may include an electronic device such as a memory to provide setting values to the image forming apparatus. As an example, the toner composition may have different printing properties than the black toner, such that a setting of the image forming apparatus may be changed to correspond to a property of the toner composition. For example, the indicator may include a value to be provided to a processor of an image forming apparatus to change a setting for an image forming operation.

[0058] In another example, a toner composition obtained using the method of FIG. 5 may be provided to a user to be included in an existing toner cartridge in which an amount of unused or undeveloped toner in the existing toner cartridge is at or near zero. For example, the toner composition may be provided to a user to be included in a black toner cartridge in which an amount of unused or undeveloped toner in the black toner cartridge is at or near zero. In that case, the toner composition may be included in a cartridge refill kit.

[0059] FIG. 6 illustrates a cartridge refill kit according to an example.

[0060] Referring to FIG. 6, a cartridge refill kit 601 may include a container

610 including a toner composition, a forming tool 620, and a plug 630. In various examples, the toner composition may include an aggregate including a plurality of toners of different color, wherein a color space characteristic of the aggregate remains within a selected color space boundary for a printable life of the toner composition. In an example, the color space of the aggregate toner may be a CIELAB color space and a boundary of the color space may include a geometric pattern in the a*/b* plane around the L* axis including at least one of a square, a rectangle, a polygon, an ellipse, a circle, or the like. Examples of a toner composition and a color space boundary have been provided above and a repetitive description will not be provided again here for sake of convenience.

[0061] The forming tool 620 may be provided to create a refill port in an existing toner cartridge. For example, the forming tool 620 may create a refill port in a toner reservoir of an existing toner cartridge to receive the toner composition from the container 610. The forming tool 620 may include a handle, an extending section, and a hole forming portion. In various examples, the hole forming portion of the forming tool 620 may include a drill, a heating iron, a punch, a saw, a tap, or the like. In various examples depending on an implementation, the forming tool 620 may include an electrical cord for connection to a power source, such as an outlet. The forming tool 620 may create the refill port in the existing toner cartridge by creating a hole, such as by a drilling, a heating, a punching, or a sawing process. In an example, the forming tool 620 may include a tap to create a hole including threads. A dimension of the forming tool 620, such as a diameter of the hole forming portion, may be correspond to a dimension of the toner composition container 610, and a dimension of the plug 630.

[0062] The plug 630 may be provided to cover the refill port that may be created by the forming tool 620. The plug 630 may include an adhesive layer to contact the existing toner cartridge at a location proximate the created refill port. In another example, the plug 630 may include an elastic or expandable material to be received within the created refill port and remain within the refill plug by a compressive force. In an example in which the forming tool 620 includes a tap, the plug 630 may include a threaded portion to be received in the refill port that includes the threads. A dimension of the plug 630 may correspond to a dimension of the forming tool 620. For example, a diameter of the plug 630 may correspond to a diameter of the hole forming portion of the forming tool 620.

[0063] It should be understood that examples described herein should be considered in a descriptive sense and not for purposes of limitation. Descriptions of features or aspects within each example should typically be considered as available for other similar features or aspects in other examples. While examples have been described with reference to the figures, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1 . A toner composition comprising: an aggregate of a plurality of toners, each of the plurality of toners being a different color, wherein the aggregate has a color space characteristic to perform monochrome printing.

2. The toner composition of claim 1 , wherein the color space characteristic to perform monochrome printing includes an a* value and a b* value in a CIELAB color space, and wherein each of the a* value and the b* value each remains within a first range for a printable life of the toner composition.

3. The toner composition of claim 2, wherein the color space characteristic to perform monochrome printing further includes an L* value in the CIELAB color space that remains within a second range for the printable life of the toner composition.

4. The toner composition of claim 3, wherein the second range of the L* value in the CIELAB color space linearly varies between <65 at 100% halftone and <90 at 25% halftone.

5. The toner composition of claim 2, wherein the first range in the CIELAB color space includes a pattern in the a*/b* plane around the L* axis including at least one of a square, a rectangle, a polygon, an ellipse, a circle, or a pattern having a continuous boundary surrounding the L* axis.

6. The toner composition of claim 1 , wherein each of the plurality of toners includes undeveloped toner obtained from a respective toner cartridge.

7. The toner composition of claim 1 , wherein the aggregate of the plurality of toners includes < 50% black toner and the remaining aggregate is comprised of > 50% of a mixture of cyan, magenta, and yellow toners.

8. The toner composition of claim 1 , wherein the aggregate of the plurality of toners includes equal percentages of cyan, magenta, and black toners.

9. The toner composition of claim 1 , wherein the aggregate of the plurality of toners includes 50% of cyan, magenta, or black toner and 25% each of the remaining two toners.

10. Atoner composition for monochrome printing, the toner composition comprising: an aggregate including a plurality of toners of different color, wherein a color point of the aggregate remains within a boundary of a color space for a printable life of the toner composition.

11. The toner composition of claim 10, wherein the color space is a CIELAB color space and the boundary includes a pattern in the a*/b* plane around the L* axis including at least one of a square, a rectangle, a polygon, an ellipse, a circle, or a pattern having a continuous boundary surrounding the L* axis.

12. The toner composition of claim 11 , wherein the color space boundary further has an L* range that linearly varies between <65 at 100% halftone and <90 at 25% halftone.

13. The toner composition of claim 10, wherein the aggregate of the plurality of toners is comprised of > 50% of one of cyan, magenta, or yellow toner.

14. A toner cartridge refill kit comprising: a toner composition; a forming tool to create a refill port coupled to a reservoir of a toner cartridge to receive the toner composition; and a plug to cover the refill port, wherein the toner composition comprises an aggregate including a plurality of toners of different color, and wherein a color point of the aggregate remains within a color space for a printable life of the toner composition.

15. The toner cartridge refill kit of claim 14, wherein the color space of the aggregate is a CIELAB color space including a geometric pattern in the a*/ b* space around the L* axis including at least one of a square, a rectangle, a polygon, an ellipse, or a circle.