Printhead accessory

In one example method, a determination is made via a processor that a document is to be printed using a printer including a printhead assembly and a printhead accessory based on a received print job. A determination is made via the processor that a first portion of the document is to be printed by the printhead assembly and a second portion is to be printed by the printhead accessory based on a characteristic of the printhead accessory. The first portion of the document is printed via the printhead assembly and the second portion of the document is printed via the printhead accessory.

BACKGROUND

Printheads in printers are used to deposit print agents onto print media. For example, the print agents may include a fluid such as an ink, a toner, or other forms of print agents.

DETAILED DESCRIPTION

Some printers may use a printhead with one color or print agent to print documents efficiently. However, such printers may not be able to print a second spot color, such as a spot color used in a company logo. Moreover, it may be difficult to effectively track such printed documents. For example, embedding security patterns or other codes into documents using a single color printhead print may result in degraded image quality or be distracting. Moreover, laser toner could potentially be scrapped off a print medium to remove security patterns embedded using the laser toner. Accordingly, it may not possible to effectively track documents printed using printers having a single monochrome printhead or laser printhead. In addition, it may not be possible to efficiently print two or more colors or to print documents using two or more types of print agents. Furthermore, although printers can print color, they may have a limited color gamut.

Described herein are techniques for printing documents using a printhead accessory. As used herein, a printhead accessory refers to an optional printhead assembly. For example, a printhead accessory can be added to a compatible stand-alone printer system and may be removable and replaceable by an end user. In some examples, a printhead accessory may be manually added to a printer system to increase or improve functionality. In some examples, the printhead accessory can be replaced with printhead accessories having other print agents or print agents of different colors. In an example system, a processor in the printer can determine that a document is to be printed using a printer including a printhead assembly and a printhead accessory based on a received print job. The processor determines that a first portion of the document to be printed by the printhead assembly and a second portion to be printed by the printhead accessory based on a characteristic of the printhead accessory. The first portion of the document is printed via the printhead assembly and the second portion of the document is printed via the printhead accessory. The techniques described herein thus enable adjustable and customizable printheads of various types to be used with a single system. In some examples, the techniques can enable spot colors to be added to a monochrome base printer. For example, a second color may be introduced into a printer using a printhead accessory. As one example, a black monochrome electrophotographic printer may have a red color printhead accessory added to provide for another color in a logo that is red and black. In some examples, the techniques also enable metadata to be included in documents using specialized print agents. As one example, the specialized print agent is an invisible fluid, such as an ultraviolet (UV) light reactive fluid or an infrared (IR) fluid. In this manner, the printed metadata may be less visually distracting or disruptive. Moreover, the use of fluidic print agents may provide for improved permanence in the case of printed security patterns. Furthermore, the techniques described herein enable multiple types of print agents to be used. For example, electrophotographically fixed toner may be combined with a fluid to generate documents with improved visual characteristics. In some examples, the techniques described herein may also enable overcoating attributes to be added to documents. For example, overcoating can include printing with an overcoat of clear fluid to change characteristics of the printed document, including color, gamut, gloss levels, water fastness, and UV protection, among other characteristics. Overcoating may also be used to provide a layer of protection for the document from fading of colors and other effects of light and heat. The techniques described herein also further enable the features described herein to be provided in a replaceable accessory device that can be used to select specific features to be added to a base printer at a lower cost than including all the features in an all-in-one integrated manner.

FIG. 1is a block diagram of an example system for printing documents using a printhead accessory. The example system is generally referred to by the reference number100. The system100includes a printer102. The printer102may be electrically and communicatively coupled to an accessory module104via a universal serial bus (USB) port106. In various examples, the USB port106may be any other interface, such as proprietary serial connections, serial peripheral interface (SPI), High-Speed Serial Interface (HSSI), PCIe, Ethernet connection, and the like. In an example, the accessory module104includes an application-specific integrated circuit (ASIC)108. The ASIC108is to provide a CPU, memory, and dedicated circuitry to execute the product firmware, process the incoming data, and prepare the incoming data to drive the physical printing mechanism to produce a printed output. In some examples, the ASIC108is an ink-capable ASIC that can operate in conjunction with fluidic printheads. The ASIC108is electrically and communicatively coupled to a flash read-only memory (ROM)110, a double data rate 3 (DDR3) synchronous dynamic random-access memory (SDRAM)112, an electrically erasable programmable read-only memory (EEPROM)114, and a set of voltage regulators and mechanism116. In some examples, the voltage regulators and mechanism116includes an analog chip that is configured to control voltages, resets, and other power supply related matters. In various examples, the voltage regulators and mechanism116is also configured to control motors, gears, among other physically moving parts in the system100. The ASIC108is further communicatively coupled to a head drive118, and a security chip120to communicate data with the head drive108and the security chip120. The ASIC108, the voltage regulators and mechanism116, the head drive118, and the security chip120are communicatively coupled to an integrated supply pen, carriage motors, and service station122.

In the example system100, the accessory module104may be connected to the printer102physically via the USB connection106. In various examples, the printer102may include a receiver bay with an interface, such as a USB port, for receiving the accessory module104. The accessory module104may thus be removable and replaceable. For example, the accessory module104can be removed and replaced when the printer is in an unpowered state. In some examples, the accessory module104can be hot-swappable and thus be removed and replaced in a powered state. In various examples, the printer102includes a dedicated receiver bay for the accessory module104. In some examples, the printer102includes an electrophotographic printing assembly and the receiver bay for the accessory module104can be located in between a finisher and a print media exit of the electrophotographic printing assembly. For example, the electrophotographic printing assembly can be a laser printing assembly. In this case, the accessory module104also provides paper transport (IPTU) functionality for the finisher device. In some examples, the receiver bay for the accessory module104is located before or after the fuser of the electrophotographic printing assembly. In some examples, the receiving bay may have an access door. In other examples, the receiving bay may have a snapping fastener that holds the accessory module104in the printer102. In some examples, the accessory module104is placed in the paper path after transfer of toner but before fusing of the toner, such that duplex printing can be performed by the accessory module104on both sides of the paper.

The accessory module104is a stand-alone independent hardware module. For example, the accessory module104can be small circuit board. In various examples, the accessory module104has its own housing, power supply, logic board, or any combination thereof. In some examples, the accessory module104can be independently serviceable and replaceable. For example, the accessory module104can be replaced with another accessory module104to provide different types of print agent, different colors of print agent, etc.

The USB connection106is used to transfer information between the printer102and the accessory module104. For example, the information can include objects to be printed, and where on a print media the object is to be printed, or the shape of the objects, among other information. In some examples, the system software of the printer102can be automatically updated via the USB connection106to support the added functionality of the accessory module104. For example, the added functionality can be an expanded color gamut, an improved security pattern printing, gloss, light protection, etc. For example, the associated embedded web server, driver, among other software of the printer102can be automatically modified in response to detecting the accessory module104via the USB connection106or any other interface, such as proprietary serial connections, serial peripheral interface (SPI), High-Speed Serial Interface (HSSI), PCIe, Ethernet connection, and the like.

In some examples, the ASIC108is a low-cost processor to render and half-tone an image. The ASIC108may communicate with the head drive118to drive the printheads. The head drive118drives printheads in the integrated supply pen122to print onto print media. In some examples, the print accessory may be controlled by the ASIC of the printer102instead of using an additional ASIC for its specific control.

In various examples, the security chip120perform various security functions. In an example, the security chip120verifies that an installed print accessory device is functional and has not been modified or broken. Further, in some examples, the security chip120verifies that the print accessory device is authentic, and not an aftermarket clone, or that consumables of the print accessory device are genuine, or that the print accessory device is being connected to a genuine printer. In some examples, the security chip120may be used to enable a secure communication channel with the printer system. The flash ROM110includes instructions used to boot the ASIC108. The DDR3 memory112is used to store intermediate data. For example, the intermediate data can include the information received from the printer102. The EEPROM114can be used to store data such as configuration data, calibration information, or other data that is to persist after power is lost. The voltage regulators116are used to provide a stable direct current (DC) voltage to the independent of the load current, temperature, or alternating current (AC) line voltage variations.

In various examples, the accessory module104includes an integrated printhead. For example, the integrated printhead may have a one-inch swath. As used herein, a swath refers to a width of the printing portion of a printhead. In some examples, the integrated printhead may have a chamber containing a print agent. In some examples, the integrated printhead is included in a scanning carriage of the accessory module104. For example, the integrated printhead is mounted in the scanning carriage. The scanning carriage is a movable carriage. As one example, the scanning carriage and supported printhead traverse over the surface of the print medium, with the nozzles ejecting droplets of print agent, at appropriate times under command of a processor, to produce a swath of droplets.

In various examples, the printer102includes a printhead assembly. For example, the printhead assembly can include an electrophotographic printhead or a fluidic printhead. As one example, an electrophotographic printhead may be a laser printhead. A fluidic printhead may be an inkjet printhead. In various examples, the accessory module104includes a carriage to mount the printhead that is a fixed carriage, also referred to herein as a stationary head. In some examples, the accessory module104includes a scanning carriage. In the case of an electrophotographic printhead with an accessory module104having a scanning carriage, the electrophotographic printing process can be temporarily delayed to allow for the scanning cartridge of the accessory module104to print onto areas of a print medium that have already passed through the printhead assembly. Thus, the scanning carriage of the accessory module104may have time to deposit a print agent by traversing over the print medium and adding additional print features, such as a spot color, security features, etc. In some examples, the delay is determined based on a size of the object to be printed by the accessory module104. As one example, a logo or a security pattern having a width less than an inch may be printed by a scanning carriage having an inch swath without any delay. In some examples, if the size of the object to be printed by the accessory module104is larger than the swath of the printheads of the scanning carriage, then a short delay may be introduced to allow for printing of the larger object. As one example, the delay may be approximately 0.2 seconds.

In various examples, the accessory module104may alternatively include a fixed carriage with a page wide swath. In some examples, if the printhead assembly is an electrophotographic printhead, then the use of a page wide swath may allow the electrophotographic printhead to print without any temporary delays, regardless of the size of the objects to be printed by the accessory module104.

In various examples, the printheads of the accessory module104can be oriented orthogonally to the direction of printing. For example, the pen can be parked and the print medium may be passed underneath without delay using a one inch swath printhead.

The block diagram ofFIG. 1is not intended to indicate that the example system100is to include all of the components shown inFIG. 1. Further, the system100may include any number of additional components not shown inFIG. 1, depending on the details of the specific implementation.

FIG. 2is a block diagram of an example system for printing documents using a printhead accessory. The system200can be implemented in the printer102ofFIG. 1, using the method300ofFIG. 3, the computer readable medium400ofFIG. 4, or in the printer500ofFIG. 5.

The system200includes a print job202. The print job202can be in the form of a page descriptor language (PDL) and is received at a print language module204. The print language module204includes a variety of PDLs, including PDL A206, PDL B208, and PDL N210. The print language module204is communicatively coupled to a color (RGB) image generator212and an object type (OT) image generator214. The RGB image generator212and the OT image generator214are communicatively coupled to a print hardware pipeline216. For example, the print hardware pipeline216is a real-time, dedicated print hardware pipeline that is to print a first portion of a document. The print hardware pipeline216includes a printhead assembly. For example, the printhead assembly can be an electrophotographic printhead assembly or a fluid printhead assembly. The system200further includes a job control firmware218communicatively coupled to the print language module204, the OT image generator214, and the print hardware pipeline216. The system200further includes an accessory device220communicatively coupled to the print hardware pipeline216and the job control firmware218. The accessory device220includes an accessory printhead222to print a second portion of a document. The accessory device220also includes an accessory subsystem224communicatively coupled to the accessory printhead222. The system200can be used to generate a printed document226having a pattern printed using the accessory printhead222.

In the example system200, a print job202is received at a printer in any suitable print language. In the example ofFIG. 2, the print job202received is in a PDL B208print language. In various examples, the print job202can be in the PDL used can be PostScript, Printer Command Language (PCL), Portable Document Format (PDF), or any other suitable PDL format. The print language module204receives the print job202and renders an RGB image212and an OT image214. The RGB image212is a set of pixel colors. The OT image214is a set of pixel types for each of the pixels. For example, each of the pixels may belong to a text object, a raster object, etc. The OT image214is used by the job control firmware218to determine how to process the RGB image212. For example, the job control firmware218can determine which of the pixels in the RGB image212are to be printed by a printhead assembly and which of the pixels are to be printed by the accessory printhead222. In various examples, the job control firmware218can automatically detect and receive information about the capabilities of the accessory printhead222upon powering of the system200. In various examples, a page analysis algorithm determines which parts of a document is to be printed by the print hardware pipeline216and which is to be printed by the accessory printhead222based on relative strengths and characteristics of the print hardware pipeline216and accessory printhead222. The page analysis algorithm then divides the print job202and directs the appropriate information to each print system. Thus, different accessory printheads222can be used within the same system200by replacing the accessory device220, either while the system200is powered off or in a powered state in the case of a hot-swappable accessory device220.

In various examples, the print hardware pipeline216can receive the RGB image212, the OT image214, and identified portion for the printhead assembly (not shown) to print from the job control firmware218and perform various processing to generate a pattern to be printed by the printhead assembly. In some examples, the printhead assembly is an electrophotographic printhead assembly, such as a laser printhead assembly or a light emitting diode (LED) printhead assembly. The print hardware pipeline216can perform enhancements, edge treatments, and half-toning, among other processing, to generate a print pattern for the printhead assembly to print. The print medium with some or all of the information in the print job202is then sent to the accessory device220for additional printing.

The accessory device220receives the print medium from the print hardware pipeline216and print job information from the job control firmware218. In various examples, the job control firmware218allocates part of the print job202to the accessory device220for printing. For example, the allocated portion of the print job202may be a spot color to be printed in a color that is different from the color of the toner or ink of the print hardware pipeline216. In this example, the job control firmware218detects the spot color capabilities of the accessory device220and the portion of the print job202corresponding to the spot color and sends the portion of the print job202corresponding to the spot color to the accessory device220for printing. In some examples, the job control firmware218allocates additional information to the accessory device220, such as metadata to be encoded into the print medium using the accessory device220. In these examples, the job control firmware218can communicate with a server to receive the metadata or generate the metadata internally. For example, the metadata can include information such as a job ID for each print job, a time stamp associated with each print job, date associated with each print job, a printer model, among other information. In various examples, the job control firmware218can also render the metadata into a pattern to be printed by the accessory device220. In some examples, the job control firmware218sends the metadata to the accessory subsystem224for rendering into the pattern. The printed pattern encoding the metadata can then be used to distinguish a printed medium from other prints. In some examples, the job control firmware218can instruct the accessory device220to apply a specialized print agent onto print the print medium. For example, the specialized print agent may be an invisible ink or a protective overcoat. In some examples, metadata is encoded into the print medium using invisible ink, such as UV ink or IR ink. In some examples, the printhead accessory includes a number of print agents. For example, the number of print agents can include print agents of different colors, or different types. In some examples, the print medium is covered with a print agent that is a protective overcoat fluid. As one example, the printed portions of the print medium are covered with an overcoat to protect against fading due to UV light, etc. Therefore, in some examples, the job control firmware218also sends the print job information that is sent to the print hardware pipeline216to the accessory subsystem224.

In various examples, the accessory subsystem224can render and store patterns, spot color information, or overcoat patterns based on the information received from the job control firmware218. In some examples, the accessory subsystem224also include a printhead controller (not shown) to control the accessory printhead222. For example, the printhead controller may cause the accessory printhead222to dispense fluid at a particular time as the print medium is passing under the accessory printhead. In some examples, the job control firmware218can cause the print medium to temporarily stop moving such that the accessory printhead222can traverse the print medium to print areas of the print medium that are larger than a swath of the accessory printhead222.

The block diagram ofFIG. 2is not intended to indicate that the example system200is to include all of the components shown inFIG. 2. Further, the system200may include any number of additional components not shown inFIG. 2, depending on the details of the specific implementation.

FIG. 3is a process flow diagram illustrating an example method for printing documents using a printhead accessory. The method300ofFIG. 3can be implemented in the systems100or200ofFIGS. 1 and 2or the computer-readable medium400ofFIG. 4or printer500ofFIG. 5.

At block302, a process determines that a document is to be printed using a printer including a printhead assembly and a printhead accessory based on a received print job. In various examples, the processor detects the printhead accessory and automatically determines the first portion and the second portion based on the characteristic of the printhead accessory. In some examples, the first portion and the second portion can be specified by a user and received as part of the print job. For example, a light production environment, a skilled operator may manually indicate which portions should be printed by either the printer or the accessory. As one example, the first portion and second portion can be specified in the case where a special spot color is mixed to be dispensed, such a company's specific color for a logo. The processor also generates a first portion printing information sent to the printhead assembly and a second portion printing information sent to the printhead accessory.

At block304, the processor determines that a first portion of the document to be printed by the printhead assembly and a second portion to be printed by the printhead accessory based on a characteristic of the printhead accessory. In various examples, the processor modifies the second portion of the document based on a velocity of a print medium and an angle of a fluid nozzle trajectory. For example, the processor can detect a spot color portion of the document to be printed by the printhead accessory and send the spot color portion of the document to the printhead accessory for printing after the first portion is printed by the printhead assembly. As one example, if the first portion of the document to be printed is in a black color and the second portion of the document to be printed is in another color, then the processor can detect portions of the document to be printed in the color and send the portions to the printhead accessory for printing. In various examples, the second portion of the document can include part of the first portion. For example, in the case of an overcoat to be applied by the printhead accessory, the second portion of the document can be the same as the first portion. In various examples, the second portion of the document is generated by the processor. As one example, the second portion is a security pattern that is generated based on metadata and printed using the printhead accessory. For example, the security pattern can be printed using an invisible fluid, such as a UV fluid or an IR fluid. In some examples, the processor can detect bordering colors and include the portion of the document with bordering colors in the second portion to be printed by the printhead accessory. For example, the printhead accessory can include multiple fluid colors. In some examples, the multiple fluid colors can include the color of toner used by the printhead assembly. Thus, the printhead accessory can be used to print bordering colors in order to prevent fluid from being printed onto toner and the smearing off the fluid on toner after printing, or to improve the visual print quality or other attribute of the resulting print.

At block306, the first portion of the document is printed via the printhead assembly and the second portion of the document is printed via the printhead accessory. In various examples, a registration of the print medium is maintained for printing the second portion of the document. For example, maintaining the registration can include maintaining a grip on a print medium after printing the first portion. In some examples, maintaining the registration includes detecting an edge of a print medium via a sensor of the printhead accessory after printing the first portion of the document, registering to the detected edge, and printing the second portion of the document. In various examples, maintaining the registration includes both maintaining the grip and registering to a detected edge. In some examples, the processor analyzes a location of the printed first portion via an in-line scanner or an in-line sensor of the printer and adjusts a timing of the printing the second portion of the document based on the location of the printed first portion.

It is to be understood that the process diagram ofFIG. 3is not intended to indicate that all of the elements of the method300are to be included in every case. Further, any number of additional elements not shown inFIG. 3may be included in the method300, depending on the details of the specific implementation. In various examples, the method300may include providing intermediate paper transport unit (IPTU) functionality via the printhead accessory during printing.

FIG. 4is a block diagram showing a tangible, non-transitory, machine-readable storage medium that stores code to direct a processor to print documents using a printhead accessory. The machine-readable medium is generally referred to by the reference number400. The machine-readable medium400can include RAM, a hard disk drive, an array of hard disk drives, an optical drive, an array of optical drives, a non-volatile memory, a flash drive, a digital versatile disk (DVD), or a compact disk (CD), among others. The machine-readable storage medium400may be accessed by a processor402over a bus404. The processor402may be a processor of a printer, such as the processor506of the printer500ofFIG. 5. In some examples, the processor402may be a field-programmable gate array (FPGA) processor and/or an ASIC processor. Furthermore, as indicated, the machine-readable medium400may include code configured to perform the methods and techniques described herein. Indeed, the various logic components discussed herein may be stored on the machine-readable medium400. Portions406,408, and410of the machine-readable storage medium400can include accessory detector module code, portion divider module code, and printing module code, respectively, which may be executable code (machine readable instructions) that direct a processor or controller in performing the techniques discussed with respect to the preceding figures.

Indeed, the various logic (e.g., instructions, code) components discussed herein may be stored on the tangible, non-transitory machine-readable medium400as indicated inFIG. 4. For example, the machine-readable medium400may include the accessory detector module code406that, when executed by a processor, direct the processor or a computing device to detect a printhead accessory. In some examples, the accessory detector module406can direct the processor or computing device to determine that a document is to be printed using a printer including a printhead assembly and a printhead accessory based on a received print job.

The machine-readable medium400may also include portion divider module code408that when executed by a processor to direct the processor or a computing device to determine a first portion of the document to be printed by the printhead assembly and a second portion to be printed by the printhead accessory based on a characteristic of the printhead accessory. For example, the characteristic of the printhead accessory can be the type of print agent used, the color of the print agent used, or the portion remaining of a print agent used. As one example, the printhead accessory is used as a reserve printing agent that is used in response to detecting that a printing agent in the printhead assembly is low or empty. In some examples, the printhead accessory is used to print the same color as the printhead assembly but using a different type of printing agent. Thus, in one example, if an electrophotographic printhead assembly is low in black toner, then the black fluid printing agent of a printhead accessory is used. In another example, the black fluid printing agent may be low or empty, and the toner is used to print the same color. In some examples, a specialty spot color may be mixed and installed for a specific print job. In this example, the printhead accessory is used to add an additional color to generate a specialty spot color. In various examples, the characteristics of the printhead accessory can also include a mechanical characteristic. For example, one or more of the mechanical characteristics of the accessory printhead may be complementary to the printing method of the printhead assembly. In some examples, the mechanical characteristic may be the mechanical operation of different printheads. For example, different fluidic printheads may have different mechanical characteristics.

In some examples, the portion divider module code408can direct the processor or computing device to automatically determine the first portion and the second portion based on the characteristic of the printhead accessory, and generate a first portion printing information sent to the printhead assembly and a second portion printing information sent to the printhead accessory. Further, the portion divider module code408can direct the processor or computing device to modify the second portion of the document based on a velocity of a print medium and an angle of a fluid nozzle trajectory.

The machine-readable medium400may further include printing module code410that, when executed by a processor, direct the processor or a computing device to print the first portion of the document via the printhead assembly and the second portion of the document via the printhead accessory. For example, the printing module code410can direct the processor or computing device to analyze a location of the printed first portion via an in-line scanner or an in-line sensor of the printer and adjust a timing of the printing the second portion of the document based on the location of the printed first portion. In some examples, the printing module code410can direct the processor or computing device to detect an edge of a print medium via a sensor of the printhead accessory after printing the first portion of the document, register to the detected edge, and print the second portion of the document based on the registered edge.

Although shown as contiguous blocks, the logic components may be stored in any order or configuration. For example, if the machine-readable medium400is a hard drive, the logic components may be stored in non-contiguous, or even overlapping, sectors.

FIG. 5is a block diagram of an example printer for printing documents using a printhead accessory. The printer500can be implemented using the system100or200ofFIGS. 1 and 2using the method300ofFIG. 3or the computer-readable medium400ofFIG. 4.

The printer500ofFIG. 5includes a printhead assembly502, a printhead accessory504, and a processor506. The processor506is communicatively coupled to both the printhead assembly502and the printhead accessory504as indicated by dual sided arrows.

In the example ofFIG. 5, the printhead assembly502of printer500is used to print a first portion of a document. For example, the printhead assembly502can be an electrophotographic printhead assembly, such as a laser printhead assembly or LED printhead assembly, or a fluidic printhead assembly, such as an inkjet printhead assembly. In some examples, the first portion of the document includes a text or diagram.

The printhead accessory504is used to print a second portion of the document. The printhead accessory504includes a printhead can be electrophotographic printhead or a fluidic printhead. In various examples, an inkjet printhead can be a piezoelectric printhead, a thermal inkjet printhead, etc. In some examples, the second portion of the document is printed in an area of the document that is separate from the first portion of the document. For example, color portions of a document may be printed by the printhead accessory504while black portions of the document are printed by the printhead assembly502. As another example, the printhead accessory504can print a security pattern in areas of the document that do not contain printing from printhead assembly502. In some examples, the second portion of the document is a color logo, a security pattern, or both. In various examples, the printhead accessory504is an electrophotographic printhead assembly, an inkjet printhead assembly, or a wax printhead assembly. The printhead accessory504can print using a print agent such as toner, a fluid such as an ink, or a wax. In some examples, the printhead accessory can print using a specialized print agent. For example, the specialized print agent can include a spot color or a specialized marking agent. In various examples, the specialized marking agent is an ultraviolent (UV) fluid. In some examples, the printhead accessory504includes a number of print agents. For example, the number of print agents can include print agents of different colors, or different types.

In some examples, the printhead accessory504includes an inline sensor. The inline sensor can be used to maintain or establish registration of the print medium after printing with the printhead assembly. For example, the inline sensor is used to detect the position and orientation of a print medium after being printed by the printhead assembly502and before being printed by the printhead accessory. In various examples, the printhead accessory is a scanning head assembly or a stationary head assembly. In some examples, the printhead accessory504also includes intermediate paper transport unit (IPTU) functionality.

The processor506determines the first portion of the document and the second portion of the document based, at least in part, on a received print job and a detected characteristic of the printhead accessory. In some examples, the processor506generates metadata including information to be printed by the printhead accessory, wherein the information is additional to the document. For example, the metadata can include document ID information.

While the present techniques may be susceptible to various modifications and alternative forms, the examples discussed above have been shown only by way of example. It is to be understood that the technique is not intended to be limited to the particular examples disclosed herein. Indeed, the present techniques include all alternatives, modifications, and equivalents falling within the scope of the appended claims.