Ink Stick Identification System

TECHNICAL FIELD

p-0002This disclosure relates generally to phase change inkjet imaging devices, and, in particular, to systems that identify ink sticks in such imaging devices.

BACKGROUND

p-0003Solid ink or phase change ink printers encompass various imaging devices, including copiers and multi-function devices. These printers offer many advantages over other types of image generating devices, such as laser and aqueous inkjet imaging devices. Solid ink or phase change ink printers conventionally receive ink in a solid form as pellets or as ink sticks. A color printer typically uses four colors of ink (cyan, magenta, yellow, and black, also referred to as “CMYK”).

p-0004The solid ink pellets or ink sticks, hereafter referred to as solid ink, sticks, or ink sticks, are delivered to a melting device, which is typically coupled to an ink loader, for conversion of the solid ink to a liquid. A typical ink loader includes multiple feed channels, one for each color of ink used in the printer. Each feed channel directs the solid ink within the channel toward a melting device located at the end of the channel. Solid ink at a terminal end of a feed channel contacts the melting device and melts to form liquid ink that can be delivered to a printhead. Inkjet ejectors in the printhead are operated using firing signals to eject ink onto a surface of an image receiving member.

p-0005In some printers, each feed channel has a separate insertion opening in which ink sticks of a particular color are placed and then are transported by a mechanical conveyor, gravity, or both along the feed channel to the melting device. In other solid ink printers, solid ink sticks of all colors are loaded into a single insertion port, where a mechanical sensor identifies the ink stick by physically contacting identification indicia on the ink sticks. An ink transport system then transports the ink stick to the proper feed channel for the inserted ink stick. Some printers include optical detection systems for ink stick identification. Such printers have multiple optical sources and/or multiple optical sensors fixed in each feed channel to detect identifying features of the ink sticks. However, providing and connecting multiple optical sources and sensors can be expensive and the light and sensor variability can result in errors in identifying features. Thus, improved ink stick identification is desirable.

SUMMARY

p-0006An ink stick detection system has been configured to detect identification features in different ink sticks with a single detector. The system includes an optical source oriented to emit light toward a first face of a solid ink stick supported in the imaging device, an optical sensor oriented to receive light reflected from the first face of the solid ink stick and configured to generate signals corresponding to an amount of received reflected light, an actuator operatively connected to one of the optical source and the optical sensor, the actuator being configured to move the one of the optical source and the optical sensor between a plurality of predetermined positions, and a controller operatively connected to the actuator and the optical sensor, the controller being configured to identify a feature of the solid ink stick from the signals generated by the optical sensor.

p-0007The system implements a method of identifying an ink stick. The method includes operating an optical source to emit light oriented at a first face of a solid ink stick supported in an imaging device, operating an actuator to move one of the optical source and an optical sensor between a plurality of positions, generating a signal with the optical sensor corresponding to an amount of reflected light received by the optical sensor when the one of the optical source and the optical sensor is at each of the plurality of positions, and identifying a feature of the solid ink stick from the signals generated by the optical sensor at each of the plurality of positions.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0008<figref idrefs="DRAWINGS">FIG. 1</figref> is a side view of one embodiment of an ink stick identification system having an optical source and an actuator operatively connected to an optical sensor to enable detection of an identifying feature in a surface of an ink stick.

p-0009<figref idrefs="DRAWINGS">FIG. 2</figref> is a side view of another embodiment of an ink stick identification system having an optical sensor and an actuator operatively connected to an optical source to enable detection of an identifying feature in a surface of an ink stick.

p-0010<figref idrefs="DRAWINGS">FIG. 3</figref> is a rear view of an eccentric drive actuator of the ink stick identification system of <figref idrefs="DRAWINGS">FIG. 2</figref>.

p-0011<figref idrefs="DRAWINGS">FIG. 4</figref> is a side view of one embodiment of an ink stick identification system having an optical source and a gear drive actuator operatively connected to an optical sensor to move the optical sensor in an arcuate path and enable detection of an identifying feature in a surface of an ink stick.

p-0012<figref idrefs="DRAWINGS">FIG. 5</figref> is a flow diagram of a process for identifying a feature of a solid ink stick.

DETAILED DESCRIPTION

p-0013For a general understanding of the present embodiments, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate like elements. As used herein, the terms “printer,” “printing device,” or “imaging device” generally refer to a device that produces an image with one or more colorants on print media and may encompass any such apparatus, such as a digital copier, bookmaking machine, facsimile machine, multi-function machine, or the like, which generates printed images for any purpose. Image data generally include information in electronic form which are rendered and used to operate the inkjet ejectors to form an ink image on the print media. These data may include text, graphics, pictures, and the like. The operation of producing images with colorants on print media, for example, graphics, text, photographs, and the like, is generally referred to herein as printing or marking. Phase-change ink printers use phase-change ink, also referred to as a solid ink, which is in a solid state at room temperature but melts into a liquid state at a higher operating temperature. The liquid ink drops are printed onto an image receiving surface in either a direct printer, which ejects directly onto media, or an indirect printer, also known as an offset transfer printer.

p-0014<figref idrefs="DRAWINGS">FIG. 1</figref> illustrates a solid ink stick identification system <b>100</b> for a solid ink printer <b>180</b>. The system <b>100</b> is positioned in the printer <b>180</b> within an ink loader <b>184</b>, which has an ink stick support <b>188</b> and an insertion port <b>192</b>. A solid ink stick <b>150</b> is inserted into the printer <b>180</b> through the insertion port <b>192</b> and rests on the ink stick support <b>188</b>. The ink stick <b>150</b> includes an identifying feature, for example surface <b>158</b>, that the ink stick identification system <b>100</b> is configured to identify. The solid ink stick <b>150</b> of <figref idrefs="DRAWINGS">FIG. 1</figref> is not depicted to scale to more clearly show the identifying feature <b>158</b>.

p-0015The ink stick identification system <b>100</b> includes an optical source <b>104</b>, an optical sensor <b>108</b>, an actuator <b>120</b>, and a controller <b>140</b>. The optical source <b>104</b> is oriented toward a face <b>154</b> of the solid ink stick <b>150</b> and is configured to emit light directed at the identifying feature, such as surface <b>158</b>, of the ink stick <b>150</b>. In one embodiment, the optical source emits diffuse light and is, for example, a 2 millimeter light-emitting diode (LED). In other embodiments, the optical source is a focused light source, for example a 2 millimeter LED laser. In further embodiments, the optical source can include any suitable size and type of light source. In the illustrated embodiment, the optical source <b>104</b> is biased downwardly by a spring <b>106</b> to the position of <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0016The optical sensor <b>108</b> is oriented toward the face <b>154</b> of the solid ink stick <b>150</b> and is configured to receive light reflected from the identifying features of the solid ink stick <b>150</b>. The optical sensor <b>108</b> generates electronic signals corresponding to an amount of light received by the sensor <b>108</b>. The sensor <b>108</b> is also operatively connected to the controller <b>140</b> to enable the optical sensor <b>108</b> to deliver the electronic signals generated to the controller <b>140</b>. In one embodiment, the optical sensor is a 2 millimeter phototransistor, though other sizes and types of optical sensors are used in other embodiments.

p-0017In the embodiment of <figref idrefs="DRAWINGS">FIG. 1</figref>, the optical source <b>104</b> and the optical sensor <b>108</b> are oriented toward the face <b>154</b> of the ink stick <b>150</b> and, when the stick is inserted into the printer, face <b>154</b> is on a side other than the side facing toward the insertion port <b>192</b> of the printer <b>180</b>. Since insertion provision and feed directions relative to the insertion opening may vary based on the ink loader configuration, the ink stick sensing features are oriented appropriately for a particular ink loader. For simplicity in the description presented below, any of the possible sensor feature sides described as being “opposite” the insertion opening means the sensor feature side is a side of the ink stick other than the side facing the insertion port. Positioning the optical source <b>104</b> and optical sensor <b>108</b> behind the ink stick <b>150</b> and above the ink stick support <b>188</b> reduces contamination of the optical source <b>104</b> and optical sensor <b>108</b> from foreign particles and debris. Furthermore, positioning the ink stick identification system <b>100</b> behind the ink loader <b>180</b> enables a more compact ink loader <b>180</b> and identification system <b>100</b>. However, in different embodiments, the optical source and optical sensor can be positioned at another suitable location proximate to the ink stick. As used herein, “detector” refers to the configuration of the optical source and optical sensor that operate together to detect the sensor feature in the sensor side of the ink stick.

p-0018The actuator <b>120</b> includes a lead screw drive <b>124</b> operatively connected to the optical sensor <b>108</b>. The actuator <b>120</b> operates to move the lead screw drive <b>124</b>, which moves the optical sensor <b>108</b> between a plurality of positions, for example positions <b>108</b>A, <b>108</b>B, and <b>108</b>C. In the illustrated embodiment, the actuator <b>120</b> moves the optical sensor <b>108</b> vertically, though in other embodiments the actuator can move the optical sensor horizontally, diagonally, in an arcuate path, or in any combination of vertical, horizontal, diagonal, and arcuate paths. The actuator <b>120</b> is operatively connected to the controller <b>140</b> to enable the controller <b>140</b> to operate the actuator <b>120</b> to move the optical sensor <b>108</b> along a range of motion within travel limits, which is referenced in this document as “the plurality of positions,” and the number of positions in this range of motion is not necessarily limited. Although not illustrated, an actuator may move one or more detectors (optical source and optical sensor) simultaneously.

p-0019As the optical sensor <b>108</b> is moved between the plurality of positions, the optical sensor <b>108</b> generates electrical signals corresponding to the amount of light reflected from the solid ink stick <b>150</b> and received by the optical sensor <b>108</b> at each position. As the optical source <b>104</b> generates the light, the magnitude and trajectory of the reflected light remains substantially constant. The light received by the optical sensor <b>108</b> therefore fluctuates with reference to the position of the optical sensor <b>108</b> and the amount of reflected light received at each position. The optical sensor <b>108</b> generates a signal corresponding to the maximum amount of received light at the position in which the optical sensor <b>108</b> receives the most direct reflection of the light from the feature <b>158</b> of the ink stick <b>150</b>. The controller <b>140</b> identifies the feature <b>158</b> of the solid ink stick <b>150</b> based on the position of the actuator <b>120</b>, and therefore the optical sensor <b>108</b>, when the signal corresponding to the maximum received light is generated.

p-0020The face <b>154</b> of the ink stick <b>150</b> includes the angled identifying surface <b>158</b>. In some embodiments, the angled surface <b>158</b> is located in an inset portion of the ink stick <b>150</b> that only extends across a portion of the face <b>154</b> of the ink stick. In other embodiments, the angled surface <b>158</b> extends across the entire width of the ink stick face. The angled surface <b>158</b> is configured to reflect light emitted by the optical source <b>104</b> in the direction of the optical sensor <b>108</b>. As shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, the ink stick <b>150</b> can be configured with the angled surface at a variety of different depths in the face <b>154</b> of the ink stick, for example <b>158</b>A and <b>158</b>B, such that light emitted from the optical source <b>108</b> reflects primarily to a different location for ink sticks having the angled surface positioned at different locations. In the embodiment of <figref idrefs="DRAWINGS">FIG. 1</figref>, the surface <b>158</b> is angled approximately 15 degrees to vertical. In other embodiments, the ink stick can have a feature surface positioned at a different vertical angle, a feature surface that is angled horizontally, or a curved feature surface, so long as the ink stick features reflect light toward a portion of the path of the optical sensor.

p-0021Operation and control of the various subsystems, components and functions of the ink loader are performed with the aid of the controller <b>140</b>. The controller <b>140</b> can be implemented with general or specialized programmable processors that execute programmed instructions. The instructions and data required to perform the programmed functions are stored in memory associated with the processors. The processors, their memories, and interface circuitry configure the controller <b>140</b> to perform the functions described above and the processes described below as the processors execute the programmed instructions stored in the memories and operate the electronic components connected to the processors through the interface circuitry. These components can be provided on a printed circuit card or provided as a circuit in an application specific integrated circuit (ASIC). Each of the circuits can be implemented with a separate processor or multiple circuits can be implemented on the same processor. Alternatively, the circuits can be implemented with discrete components or circuits provided in VLSI circuits. Also, the circuits described herein can be implemented with a combination of processors, ASICs, discrete components, or VLSI circuits.

p-0022In operation, a user inserts a solid ink stick <b>150</b> into the ink loader <b>184</b> through the insertion port <b>192</b> to rest on the ink stick support <b>188</b>. In the embodiment depicted in <figref idrefs="DRAWINGS">FIG. 1</figref>, the optical sensor <b>108</b> is configured to rest in position <b>108</b>A, and the optical sensor <b>108</b> contacts the optical source <b>104</b> to retain the optical source <b>104</b> against the force of spring <b>106</b> in position <b>104</b>A. In position <b>104</b>A, the optical source <b>104</b> emits light that reflects off surface <b>154</b> toward the optical sensor <b>108</b> in position <b>108</b>A. When an ink stick <b>150</b> is present in the ink loader <b>184</b>, the light emitted by the optical source <b>104</b> in position <b>104</b>A reflects to the optical sensor <b>108</b> in position <b>108</b>A, and the sensor <b>108</b> generates an electronic signal that is delivered to the controller <b>140</b> indicating that the ink stick <b>150</b> is present in the ink loader <b>184</b>. In other embodiments, the ink loader can include a separate detector that signals to the controller the presence of an ink stick in the ink loader. Differentiating between the ink loader state prior to and just after an ink stick is inserted may not need a high signal strength, as from a direct reflection into the optical detector, so a simplified configuration of the “stationary” optical detector where no motion occurs is envisioned for desirable cost containment. An alternative intended to ensure high insertion detection signal strength is depicted in <figref idrefs="DRAWINGS">FIG. 1</figref> and described below. The optical light source may be cycled on or pulsed when the access door or cover to the ink loader is lifted, so as to detect when an ink stick is inserted or in printers having multiple feed channels, in which channel the ink stick has been inserted.

p-0023Once the ink stick <b>150</b> is positioned in the ink loader <b>184</b>, the controller <b>140</b> operates the optical source <b>104</b> to emit light at the surface <b>154</b> of the ink stick <b>150</b>. As the optical source <b>104</b> emits light at surface <b>154</b>, the controller <b>140</b> operates the actuator <b>120</b> to move the optical sensor <b>108</b> between the plurality of positions <b>108</b>A-C. In <figref idrefs="DRAWINGS">FIG. 1</figref>, the optical source <b>104</b> is biased downwardly by the spring <b>106</b>, and as the optical sensor <b>108</b> moves downwardly from position <b>108</b>A, the optical source <b>104</b> moves to and remains in the position shown in <figref idrefs="DRAWINGS">FIG. 1</figref>. The optical sensor <b>108</b> continues to move downwardly to the position of <figref idrefs="DRAWINGS">FIG. 1</figref> and then to positions <b>108</b>B and <b>108</b>C as the sensor <b>108</b> generates electronic signals corresponding to the amount of reflected light received by the sensor <b>108</b> at the different positions. In one embodiment, the optical sensor generates the signals only at the predetermined positions, while in other embodiments the optical sensor is configured to generate electronic signals substantially continuously as the optical sensor is moved.

p-0024As shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, the ink stick <b>150</b> includes identifying surface <b>158</b>, such that the light emitted by the optical source <b>104</b> reflects toward the optical sensor <b>108</b> in the position shown in <figref idrefs="DRAWINGS">FIG. 1</figref>. The optical sensor <b>108</b> therefore generates a signal indicating a peak amount of received light when the sensor <b>108</b> is in the position of <figref idrefs="DRAWINGS">FIG. 1</figref>. As the actuator <b>120</b> moves the optical sensor <b>108</b> downwardly to positions <b>108</b>B and <b>108</b>C, the sensor <b>108</b> receives less reflected light, and the signals generated by the sensor <b>108</b> are reduced accordingly to indicate the lesser amounts of received light. The controller <b>140</b> identifies the peak signal generated by the optical sensor <b>108</b>, and correlates the peak signal to the position of the optical sensor <b>108</b> when the peak signal is generated. The controller <b>140</b> then identifies, based on the position of the optical sensor <b>108</b> at which the peak signal is generated, that the solid ink stick <b>150</b> includes feature surface <b>158</b>. The actuator <b>120</b> can be a stepper motor so sensor position can be correlated to motor counts. Determining positions in a motion mechanism is a well-known process and can be accomplished with a variety of well-known methods not described herein.

p-0025Other ink sticks can include identifying surfaces <b>158</b>B or <b>158</b>C in place of surface <b>158</b> to indicate different properties of the solid ink sticks. An ink stick having identifying surface <b>158</b>B reflects light primarily to position <b>108</b>B, such that the optical sensor <b>108</b> generates the signal corresponding to the peak amount of light received when in position <b>108</b>B. Likewise, an ink stick having identifying surface <b>158</b>C reflects light primarily toward position <b>108</b>C, and the optical sensor <b>108</b> generates the signal corresponding to the peak amount of light received when in position <b>108</b>C. Consequently, the structure that enables the optical sensor <b>108</b> to move enables the ink stick identification system <b>180</b> to identify ink sticks having different identifying features at a single insertion port.

p-0026Although three identifying surfaces are illustrated in the embodiment of <figref idrefs="DRAWINGS">FIG. 1</figref>, the reader should appreciate that the ink stick identification system can be utilized in a printer configured to accept ink sticks having identification surfaces in other positions or orientations. The ink stick identification system can be configured to move the optical sensor to any suitable number of predetermined positions to identify feature surfaces in other positions or orientations. Additionally, since the actuator moves the optical sensor, the ink stick identification system <b>100</b> is versatile for use in different printer models to identify features defined on ink sticks having different shapes and sizes. Some printers can include multiple identification systems installed in a single ink loader to enable identification of a larger number of features on an ink stick.

p-0027The ink stick identification system <b>100</b> enables improved identification of solid ink sticks <b>150</b>. Over time, contamination from foreign particles and normal wear can result in an optical source generating a light having lower intensity than light from a newer optical source. Further, contamination and general sensor variability can affect the magnitude of the signal generated by optical sensor. Some systems, for example those systems having multiple optical sources or optical sensors, identify ink sticks by identifying a sensor signal having an amplitude greater than a threshold value. However, the variability of optical sources and sensors can result in the sensor failing to generate a signal greater than the threshold, and therefore failing to identify an ink stick. The solid ink stick identification system <b>180</b> is configured to identify the ink stick from the peak amplitude generated by the single optical source <b>104</b> and optical sensor <b>108</b> pair. The peak signal is always generated by the optical sensor <b>108</b> at the position where the light most directly reflects off the ink stick <b>150</b> toward the sensor <b>108</b>, regardless of the contamination or variability of the optical source <b>104</b> and optical sensor <b>108</b> in the system <b>180</b>.

p-0028The ink sticks identified by the ink stick identification system <b>180</b> can be manufactured simply and economically. The ink sticks can be produced with different feature surfaces <b>158</b>, <b>158</b>B, and <b>158</b>C simply by moving a tool slide in an ink stick mold used to produce the ink sticks to a different position during the ink stick fabrication process.

p-0029Some printers include a separate ink loader for each color of ink stick utilized by the printer. Such printers can include a separate ink stick identification system for each ink loader. Other printers include an optical source and sensor for each ink loader, and the optical sensors are operatively connected to a single actuator that moves all of the optical sensors when an ink stick is inserted in any one of the ink loaders.

p-0030<figref idrefs="DRAWINGS">FIG. 2</figref> illustrates another solid ink stick identification system <b>200</b> for a solid ink printer <b>180</b>. The system <b>200</b> is positioned in the printer <b>180</b> within an ink loader <b>184</b> and proximate to an ink stick <b>150</b>, both of which are configured to function optically in a manner similar to the ink loader <b>184</b> and ink stick <b>150</b> described with reference to <figref idrefs="DRAWINGS">FIG. 1</figref>, but with the insertion opening being located on a different side of the loader in <figref idrefs="DRAWINGS">FIG. 2</figref>.

p-0031The ink stick identification system <b>200</b> includes an optical source <b>204</b>, an optical sensor <b>208</b>, an actuator <b>220</b>, and a controller <b>240</b>. The optical source <b>204</b> is oriented toward the face <b>154</b> of the solid ink stick <b>150</b> and is configured to emit light directed at the identifying feature, for example surface <b>158</b>, of the ink stick <b>150</b>.

p-0032The optical sensor <b>208</b> is oriented toward the face <b>154</b> of the solid ink stick <b>150</b> and is configured to receive light reflected from the identifying features of the solid ink stick <b>150</b>. The optical sensor <b>208</b> generates electronic signals corresponding to an amount of light received by the sensor <b>208</b>. The sensor <b>208</b> is also operatively connected to the controller <b>140</b> to enable the optical sensor <b>208</b> to deliver the generated electronic signals to the controller <b>140</b>.

p-0033The actuator <b>220</b> is operatively connected to and configured to move the optical source <b>204</b>. As shown in <figref idrefs="DRAWINGS">FIG. 3</figref>, the actuator <b>220</b> includes an eccentric drive <b>222</b>, a pivoting member <b>224</b>, an elongated member <b>228</b>, and a mount <b>232</b>. The eccentric drive <b>222</b> operates to move the components of the actuator <b>220</b> between the position shown in <figref idrefs="DRAWINGS">FIG. 3</figref>, which corresponds to position <b>204</b>B of the optical source <b>204</b>, and the upper position, wherein the actuator <b>220</b> components are in positions <b>222</b>A, <b>224</b>A, <b>228</b>A, and <b>232</b>A and the optical source <b>204</b> is in the position of <figref idrefs="DRAWINGS">FIG. 2</figref>.

p-0034As the optical source <b>204</b> is moved between the plurality of positions, the optical sensor <b>208</b> generates electrical signals corresponding to the amount of reflected light received from the solid ink stick <b>150</b> at each position. The intensity of the reflected light remains substantially constant, while the trajectory of the reflected light varies with the movement of the optical source <b>204</b>. The light received by the optical sensor <b>208</b> is therefore a function of the position of the optical source <b>204</b>. The optical sensor <b>208</b> generates a signal corresponding to the maximum amount of received light when the optical source <b>204</b> is at the position in which the light most directly reflects from the feature <b>158</b> of the ink stick <b>150</b> toward the optical sensor <b>208</b>. The controller <b>240</b> identifies the feature <b>158</b> of the solid ink stick <b>150</b> based on the position of the actuator <b>220</b>, and therefore the optical source <b>204</b>, when the signal corresponding to the maximum received light is generated.

p-0035The face <b>154</b> of the ink stick <b>150</b> includes the angled identifying surface <b>158</b>, which is configured to reflect light emitted by the optical source <b>204</b> in the direction of the optical sensor <b>208</b>. As shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, the ink stick <b>150</b> can be configured with the angled surface at a variety of different depths in the face <b>154</b> of the ink stick, for example <b>158</b>A and <b>158</b>B, such that the ink sticks having different feature depths reflect light primarily toward the optical sensor <b>208</b> at different positions of the optical source <b>204</b>.

p-0036In operation, a user fully inserts a solid ink stick <b>150</b> into the ink loader <b>184</b> through the insertion port <b>192</b> such that the ink stick <b>150</b> rests on the ink stick support <b>188</b>. The controller <b>240</b> receives a signal from a sensor system or other mechanism that detects the presence of an ink stick to indicate to the controller <b>240</b> that the ink stick <b>150</b> has been inserted into the ink loader <b>184</b>.

p-0037Once the ink stick <b>150</b> is positioned in the ink loader <b>184</b>, the controller <b>240</b> operates the optical source <b>204</b> to emit light at the surface <b>154</b> of the ink stick <b>150</b>. As the optical source <b>204</b> emits light at surface <b>154</b>, the controller <b>240</b> operates the eccentric drive <b>222</b>. In the position of <figref idrefs="DRAWINGS">FIG. 3</figref>, the eccentric drive <b>222</b> is in the left-most position, resulting in the pivoting members <b>224</b> being at an angle relative to vertical. The elongated member <b>228</b> is therefore in a lower position, and the attached mount <b>232</b> is also in a lower position. The optical source <b>204</b> (<figref idrefs="DRAWINGS">FIG. 2</figref>), which is attached or movably interfaced to the mount <b>232</b>, is thus also in the lower position <b>204</b>B. As the eccentric drive <b>222</b> moves toward position <b>222</b>A, the pivoting member <b>224</b> moves toward the vertical position <b>224</b>A, urging the elongated member <b>228</b> and mount <b>232</b> upwardly toward positions <b>228</b>A and <b>232</b>A, respectively. The actuator <b>220</b> is configured to move the optical source <b>204</b> an overall vertical distance represented by <b>236</b> to move the optical source <b>204</b> between the plurality of positions shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. Low cost mechanisms are essential in modern products. In <figref idrefs="DRAWINGS">FIG. 2</figref> only one detector is visible, though additional detectors can be positioned directly behind or in front of those shown. The elongated member <b>228</b> shown in the example mechanism of <figref idrefs="DRAWINGS">FIG. 3</figref> illustrates one possible configuration that simultaneously and efficiently moves multiple detectors across a plurality of ink loader color channels (not shown). In a multiple detector arrangement, the detectors are aligned with color channels and may be positioned with uniform or non-uniform spacing along the width of member <b>228</b>

p-0038As the optical source <b>204</b> is moved, the optical sensor <b>208</b> generates electronic signals corresponding to the amount of reflected light received by the sensor <b>208</b> at the various positions of the optical source <b>204</b>. As shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, the ink stick <b>150</b> includes identifying surface <b>158</b>, such that the light emitted by the optical source <b>204</b> reflects most directly toward the optical sensor <b>208</b> when the optical source <b>204</b> is in the position shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. The optical sensor <b>208</b> therefore generates a signal indicating a peak amount of received light when the source <b>204</b> is in the position of <figref idrefs="DRAWINGS">FIG. 2</figref>. As the actuator <b>220</b> moves the optical source <b>204</b> to positions <b>204</b>B and <b>204</b>C, the sensor <b>208</b> receives less reflected light, and the signals generated by the sensor <b>208</b> indicate the lesser amounts of received light. The controller <b>240</b> identifies the peak signal generated by the optical sensor <b>208</b>, and correlates the peak signal to the position of the optical source <b>204</b> when the peak signal is generated. The controller <b>240</b> then identifies, based on the position of the optical source <b>204</b> when the peak signal is generated, that the solid ink stick <b>150</b> includes feature surface <b>158</b>.

p-0039Another embodiment of a solid ink stick identification system <b>300</b> for a solid ink printer is illustrated in <figref idrefs="DRAWINGS">FIG. 4</figref>. The system <b>300</b> is positioned in the printer within an ink loader and oriented toward a face <b>354</b> of an ink stick <b>350</b> in the ink loader. The face <b>354</b> includes an identifying feature, for example surface <b>358</b>, that the ink stick identification system <b>300</b> is configured to identify.

p-0040The ink stick identification system <b>300</b> includes an optical source <b>304</b>, an optical sensor <b>308</b>, an actuator <b>320</b>, and a controller <b>340</b>. The optical source <b>304</b> is oriented toward the face <b>354</b> of the solid ink stick <b>350</b> and is configured to emit light directed toward the identifying feature, surface <b>358</b>, of the ink stick <b>350</b>.

p-0041The optical sensor <b>308</b> is oriented toward the face <b>354</b> of the solid ink stick <b>350</b> and is configured to receive light reflected from the identifying features of the solid ink stick <b>350</b>. The optical sensor <b>308</b> generates electronic signals corresponding to an amount of light received by the sensor <b>308</b>. The sensor <b>308</b> is also operatively connected to the controller <b>340</b> to enable the optical sensor <b>308</b> to deliver the electronic signals generated to the controller <b>340</b>.

p-0042The actuator <b>320</b> includes a pinion gear <b>324</b> that meshes with an arcuate rack gear <b>328</b> on which the optical sensor <b>308</b> is mounted. The actuator <b>320</b> operates in response to a control signal generated by controller <b>340</b> to turn the pinion gear <b>324</b>, which moves the rack gear <b>328</b> and the optical sensor <b>308</b> in an arcuate path between a plurality of positions, for example positions <b>308</b>A and <b>308</b>B. The actuator <b>320</b> is operatively connected to the controller <b>340</b> to enable the controller <b>340</b> to operate the actuator <b>320</b> to move the optical sensor <b>308</b> between the plurality of positions.

p-0043As the optical sensor <b>308</b> is moved between the plurality of positions, the optical sensor <b>308</b> generates electrical signals corresponding to the amount of reflected light received from the solid ink stick <b>350</b> at each position. As the optical source <b>304</b> generates the light, the magnitude and trajectory of the reflected light remains substantially constant. The light received by the optical sensor <b>308</b> therefore fluctuates only due to the position of the optical sensor <b>308</b> with respect to the reflected light. The optical sensor <b>308</b> generates a signal corresponding to the maximum amount of received light at the position in which the optical sensor <b>308</b> receives the most direct reflection of the light from the feature <b>358</b> of the ink stick <b>350</b>. The controller <b>340</b> identifies the feature <b>358</b> of the solid ink stick <b>350</b> based on the position of the actuator <b>320</b>, and therefore the optical sensor <b>308</b>, when the signal corresponding to the maximum received light is generated.

p-0044The face <b>354</b> of the ink stick <b>350</b> includes the protruding angled identifying surface <b>358</b>. The angled surface <b>358</b> is configured to reflect light emitted by the optical source <b>304</b> in the direction of the optical sensor <b>308</b>. As shown in <figref idrefs="DRAWINGS">FIG. 4</figref>, the ink stick <b>350</b> can be configured for ink stick differentiation with the angled surface at different angles relative to vertical, as depicted by alternate feature surfaces <b>358</b>A and <b>358</b>B, such that light emitted from the optical source <b>308</b> reflects primarily to a different location for ink sticks having the feature surfaces at different angles. The angled surface feature can protrude outboard of the general ink stick shape, as shown in <figref idrefs="DRAWINGS">FIG. 4</figref>, or be inset, or, with respect to the various possible angles, be a combination of protruding or inset features.

p-0045In operation, a user inserts a solid ink stick <b>350</b> into the ink loader of the printer. A sensor system in the ink loader signals to the controller that an ink stick is present in the ink loader. Once the ink stick <b>350</b> is positioned in the ink loader, the controller <b>340</b> operates the optical source <b>304</b> to emit light at the surface <b>354</b> of the ink stick <b>350</b>. As the optical source <b>304</b> emits light at surface <b>354</b>, the controller <b>340</b> operates the actuator <b>320</b> to move the optical sensor <b>308</b> between the plurality of positions <b>308</b>A-<b>308</b>B. The optical sensor <b>308</b> moves between position <b>308</b>A, the position of <figref idrefs="DRAWINGS">FIG. 4</figref>, and position <b>308</b>B in the arcuate path defined by the curved rack gear <b>328</b> as the sensor <b>308</b> generates electronic signals corresponding to the amount of reflected light received by the sensor <b>308</b> at the positions.

p-0046As shown in <figref idrefs="DRAWINGS">FIG. 4</figref>, the ink stick <b>350</b> includes identifying surface <b>358</b> to reflect the light emitted by the optical source <b>304</b> toward the optical sensor <b>308</b> in the position shown in <figref idrefs="DRAWINGS">FIG. 4</figref>. The optical sensor <b>308</b> therefore generates a signal indicating a peak amount of received light when the sensor <b>308</b> is in the position of <figref idrefs="DRAWINGS">FIG. 4</figref>. As the actuator <b>320</b> moves the optical sensor <b>308</b> between positions <b>308</b>A and <b>308</b>B, the sensor <b>308</b> receives less reflected light, and the signals generated by the sensor <b>308</b> at positions <b>308</b>A and <b>308</b>B indicate the lesser amounts of received light. The controller <b>340</b> identifies the peak signal generated by the optical sensor <b>308</b>, and correlates the peak signal to the position of the optical sensor <b>308</b> when the peak signal is generated. The controller <b>340</b> then identifies, based on the position of the optical sensor <b>308</b> where the peak signal is generated, that the solid ink stick <b>350</b> includes feature surface <b>358</b>.

p-0047Other ink sticks placed on the ink stick support can include identifying surfaces <b>358</b>A or <b>358</b>B in place of surface <b>358</b> to indicate different properties of the solid ink sticks. An ink stick having identifying surface <b>358</b>A reflects light primarily to position <b>308</b>A, such that the optical sensor <b>308</b> generates the signal corresponding to the peak amount of light received when in position <b>308</b>A. Likewise, an ink stick having identifying surface <b>358</b>B reflects light primarily toward position <b>308</b>B, and the optical sensor <b>308</b> generates the signal corresponding to the peak amount of light received when in position <b>308</b>B.

p-0048<figref idrefs="DRAWINGS">FIG. 5</figref> illustrates a method <b>500</b> for identifying a solid ink stick in a solid ink printer having an ink stick identification system such as one of those described in <figref idrefs="DRAWINGS">FIG. 1-FIG</figref>. <b>4</b>. In the description of the method, a statement that the process does some function or performs some action refers to a controller executing programmed instructions to do the function or perform the action or to the controller generating signals to operate one or more electrical or electromechanical components to perform the function or action.

p-0049The process begins with the controller receiving a signal indicating that an ink stick is present in the ink loader of the printer (block <b>510</b>). The signal can be generated by the optical sensor of the identification system in response to receiving light reflected from the ink stick in the ink loader, or the signal can be generated by another sensor system or other mechanism configured to detect a solid ink stick in the ink loader.

p-0050Once the signal is received, the controller operates the optical source to emit light at a face of the ink stick in the ink loader (block <b>520</b>). The actuator is be configured to move one of the optical sensor and the optical source between a plurality of positions. While the optical source emits light at the face of the ink stick in a continuous, pulsed or time/position fashion, the controller operates the actuator to move one of the optical source and the optical sensor to a predetermined position (block <b>530</b>). Once the optical source or optical sensor is moved to the predetermined position, the optical sensor generates an electrical signal corresponding to an amount of light reflecting from the solid ink stick to the optical sensor (block <b>540</b>). In some embodiments, the optical sensor can be configured to generate signals continuously while the actuator is being operated between the positions. The controller then evaluates whether the sensor or source are moved to additional predetermined positions (block <b>550</b>). If there are additional predetermined positions, the process continues at block <b>530</b>.

p-0051After the one of the optical source and optical sensor has been moved to all the predetermined positions, the controller evaluates the signals received from the optical sensor at the various positions of the optical source or sensor to identify the feature of the solid ink stick (block <b>560</b>). The controller identifies the signal generated by the sensor corresponding to the maximum magnitude of reflected light received by the optical sensor. The controller determines the position of the one of the optical source and the optical sensor when the signal corresponding to the maximum received reflected light is received and, based on the position of the one of the optical source and the optical sensor when the maximum signal is generated, the controller identifies the feature present in the solid ink stick to identify the solid ink stick in the ink loader. The sensing operations described above can be performed for one or more than one insertion locations or feed channels, as appropriate to a particular ink loader and based on ink stick insertions. For example, a black and a yellow ink stick might be inserted at the same time in a loader with multiple insertion openings. In such a scenario, the ink stick identification process can be accomplished for one stick and then for the other or for both simultaneously.

p-0052It will be appreciated that variations of the above-disclosed apparatus and other features, and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art, which are also intended to be encompassed by the following claims.