[00011 Imaging devices, such as printers and photocopiers may print content onto a medium, such as paper. The medium on which the content is to be printed is held in an input tray of the imaging device. A user may initiate a print command, and the imaging device may execute the print command to print the content on the medium. The printed medium is collected in an output tray of the imaging device.

BRIEF DESCRIPTION OF THE DRAWINGS

[00021 The following detailed description references the drawings, wherein:

[00031 Fig. 1 illustrates a schematic block diagram of an imaging device, in accordance with an example:

[00043 Fig. 2a illustrates a schematic diagram of the imaging device with an output tray of the imaging device in a retracted position , in accordance with an example;

[0005] Fig. 2b illustrates a cross-sectional view of the imaging device with the output tray in the retracted position, in accordance with an example;

[øøø$! Fig. 2c i!iustrates an alignment of a light blocking element with respect to an optical sensor array of the imaging device in the retracted position of the output tray, in accordance with an example;

[00073 Fig. 3a illustrates a schematic diagram of the imaging device with the output tray of the imaging device in an extended position, in accordance with an example; [0008] Fig. 3b illustrates a cross-sectional view of the imaging device with the output tray in the extended position, in accordance with an example;

[0009] Fig. 3c illustrates an alignment of the light blocking element with respect to the optical sensor array of the imaging device in the extended position of the output tray, in accordance with an example;

[0010] Fig. 4 illustrates a schematic block diagram of an Imaging device, in accordance with an example;

[0011] Fig. 5 illustrates a schematic block diagram of an imaging device, in accordance with an example;

[0012] Fig 6a illustrates the light blocking element, in accordance with an example; and

[00133 Fig. 6b illustrates the light blocking element, in accordance with another example.

DETAILED DESCRIPTION

[00143 In an imaging device, an output tray can be move between an extended position and a retracted position. In the extended position, the output tray is fully stretched and protrudes out of the imaging device, and in the retracted position, the output tray may be partly extended or fully closed and held within the imaging device. In an example, the output tray, in the extended position, is fully stretched and protrudes out from a slot. The slot is at the exit of a media path in a printer, through which printed media is also discharged. The media path may be a path followed by a medium from an input tray into the output tray.

[001 S] For the imaging device to start a printing operation, the output tray is to be maintained in the extended position. Otherwise, the printed media may spill out from the imaging device due to Sack of supporting structure, the printed media may curl and deform, and media jam may occur at the output tray.

[00163 Before initiating the printing operation, the imaging device may check whether the output tray is in the extended position or not. The imaging device generally employs a complex arrangement of latches and sensors to detect the position of the output tray. Also, in some imaging devices, the output tray is automatically moved to the extended position before Initiating the print operation. Such imaging devices use complex arrangement of linkages, sensors, and other mechanical members to ensure automatic movement of the output tray.

[00173 The present subject matter describes a simple technique for defection of positions of the output tray which does not involve the complex arrangement of latches and sensors in an example of the present subject matter describes imaging devices in which optical sensors that are used tor detection of media stack height in the output tray are aiso utilized to determine the position of the output tray. The present subject matter facilitates in eliminating the complex arrangement of latches and sensors, expensive hardware for automated movement of the output tray, and additional sensors that are otherwise used for defection of position of the output tray.

[00183 In an example, an imaging device includes an optical sensor array for detection of stack height of media in an output tray of the imaging device and a light blocking element coupled to the output tray in a retracted position of the output tray, the Sight blocking element blocks an optical sensor of the optical sensor array and in the extended position of the output tray, the Sight blocking sensor unblocks ail the optical sensors in the optical sensor array. Thus, the light blocking element varies an output signal of the optical sensor array depending on the position of the output tray. The imaging device includes a position detection module coupled to the optical sensor array. The position detection module determines the output tray to be in the extended position or the retracted position, based on the output signal of the optical sensor array. Thus, the present subject matter provides a simple and cost-effective technique of determining the position of the output tray.

[00183 Further, in art example of the present subject matter, when a print command is given to the imaging device and the output tray is in the retracted position, the print command is put on hold until the output tray is moved to the extended position. Once the output tray is moved to the extended position, then the print command is executed. Therefore, with the present subject matter, the issues of spilling out of printed media from the imaging device and curling and/or deforming of printed media discharge from the imaging device are also eliminated.

£0020| The above described implementations are further elaborated with reference to the Figures, it should be noted that the description and figures merely illustrate the principles of the present subject matter along with examples described herein and, should not be construed as a limitation to the present subject matter it is thus noted that various arrangements may be devised that, although not explicitly described or shown herein, describe the principles of the present subject matter. Moreover, aii statements herein reciting principles, aspects , and examples of the present subject matter, as well as specific examples thereof, are Intended to encompass equivalents thereof.

[OG213 Fig. 1 illustrates a schematic bioc diagram of an imaging device 100, in accordance with an exampie. in an example, the imaging device 100 Incudes a printer, a photocopier, or the like. Fig. 1 shows a top view of the imaging device 100. The imaging device 100 includes an output tray 102 movable, in directions as indicated by arrow W, between an extended position and a retracted position in Fig. 1 , the output tray at the extended position is referenced as 102a and the output tray in the retracted position is referenced as 102b.

[00223 In the extended position, the output tray 102 is fully stretched and protrudes out of the imaging device TOO The output tray 102 in the extended position holds printed media discharged from the imaging device 100. In the retracted position, the output tray is either fully or partly retained within the imaging device 100.

[00233 In an exampie, the output tray 102 can be drawn out of a slot (not shown) of the imaging device 100 to move the output tray 102 from the retracted position to the extended position. The slot may be an opening at the exit of a media path of the imaging device through which media is conveyed for printing. The output tray 102 in the extended position may be pushed to slide through the siot (not shown) to move the output tray 102 from the extended position to the retracted position. [00243 Tiie imag ng device 100 further includes an optical sensor array 104 to detect a stack height of media in the output tray 102. In an example, the optical sensor array 104 includes multiple sensors which detect presence of media up to a certain height in the output tray 102 based on receiving light or receiving no light from an optical source (not shown) in the imaging device 100. The optical source may be on the other side of the output tray 102, in the line of sight of the optical sensor array 104, Detection of stack height by the optical sensor array 104 is described later in the description

[0025J The imaging device 100 also includes a light blocking element 106 coupled to the output tray 102 to block an optical sensor of the optical sensor array 104 when the output tray 10 Is in the retracted position in an example, the light blocking element 106 may be made from plastic and is configured to block one optical sensor In the optical sensor array 104 Since, the light blocking element 106 blocks the sensor, the blocked sensor receives no light from the optical source.

[00263 The imaging device 100 also includes a position detection module 108 coupled to the optical sensor array 104. In an example implementation, the position detection module 108 may be implemented as hardware, such as a processor(s) or through logical instructions or a combination thereof. In a example implementation, the processors) may be external to the position detection module 108 and may be coupled to the position detection module 108. The processorfs) may be implemented as microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processors) may fetch and execute computer-readable instructions stored in a memory coupied to the processor(s). The memory can be internal or external to the imaging device 100. The memory may include any non-transltory computer-readable storage mediu including, for example, volatile memory (e.g., RAM), and/or non-volatile memory (e.g., EPROM, flash memory, NVRAM, memristof, etc.). The functions of the various elements shown in Fig. 1 , including any functional blocks labeled as "processors}’’ , may be provided through the use of dedicated hardware as wet! as hardware capable of executing computer-readable instructions.

{00271 The position detection module 108 amongst other things include routines, programs, objects, components, data structures, and the like, which perform particular tasks or implement particular abstract data types. The position detection module 108 may be coupled to, and executed by, processors) to perform various functions for the purpose of detecting positions of the output tray 102, in accordance with the present subject matter. In an example implementation, the position detection module 108 may be coupled to other modules to control a printing operation in the imaging device 100. The position detection module 108 can determine, based on an output signal of the optical sensor array 104, whether the output tray 102 is in the extended position or in the retracted position

[00283 Fi . 2a illustrates a schematic diagram of the imaging device 200 with an output tray 102 in the retracted position, in accordance with an example. Fig. 2b Illustrates a cross-sectional view of the imaging device 200 with the output tray 102 in the retracted position, in accordance with an example.

[00293 Referring to Fig. 2a, the imaging device 200 includes the output tray 102. The output tray 102 Includes a first segment 202. In the retracted position of the output tray 102, the first segment 202 Is in a first position and remains completely inside the imaging device 200 as illustrated in Fig. 2a. As shown in Fig. 2a, in the first position, the first segment 202 is fully retained within a slot 204 in the body of the imaging device 200. The slot 204 is an opening at the exit of a media path of the imaging device 200. The media path of the imaging device 200 is a pathway through which a medium is conveyed through the imaging device 200 for being printed. The output tray 102 also includes a second segment 206 coupled to the first segment 202. The second segment 208 may be slidably fitted in a channel (not shown) within the first segment 202 and may be moved along the channel to move the second segment 206 between a fully extended position and an unextended position. In the retracted position of the output tray, the second segment 208 is either partly or full retained within the first segment 202. The output tray 102 further includes a third segment 208 coupled to the second segment 208. The thir segment 208 is positioned at the end of the second segment 208 and prevents printed media accumulated on the output tray 102 from failing off.

[0030] The imaging device 200 includes an optica! source 210. The optica! source 210 may be a source of visible light, Ultraviolet (UV) radiation, or infrared (IR) radiation. The optical source 210 is housed within the imaging device 200 at a first side‘A of the output tray 102, as depicted in Figs.2a and 2b. in an example, the optical source 210 may be positioned on a fixture (not shown) of the imaging device 200 at a first side of the output tray 102. in an example, the height at which the optica! source 210 is positioned corresponds to a maximum stack height of media that can be accommodated on the output tray 102. The optical source 210 emits radiation towards a secon side of the output tray 102, opposite to the first side, such that the emitted radiation is directed towards an optical sensor array 104 housed within the imaging device 200 at the second side of the output tray 102, as depicted in Figs, 2a and 2b.

[0031J The optical sensor array 104 includes a first optica! sensor 212-1 , a second optical sensor 212-2, and a third optical sensor 212-3. in an example, the optica! sensor array 104 may include more than three optical sensors in an example, the optica! sensors may be phototransistors which can sense visible light, UV radiation, and infrared SR radiation. The optical sensor array 104 detects slack height of printed media accumulated on the output tra 102.

[00323 The optical sensor array 104 may detect the radiation from the optical source 210 and provide an output signal based on which height of media in the output tray 102 can be detected. During a printing operation, depending on which of the optical sensors in the optical sensor array 104 receives the emitted radiation, the height of the media in the output tray 102 is determined. For example, when the stack height of the printed media accumulated on the output tray 102 reaches a Sow stack zone 214, radiation directed towards the first optical sensor 212-1 located at the base of the optlcai sensor array 104 is blocked . In an example, the Sow stack zone 214 corresponds to a low level of media, such as 10 to 20 numbers of ordinary A4 sheets, being present in the output tray 102. In an example, the imaging device 200 may include a control unit (not shown) which may analyze the output signal of the optical sensor array 104 which indicates no tight being received by the first optical sensor 212-1 and light being received by the second optical sensor 212-2 and the third optical sensor 212-3, to determine that the stack height of the media accumulated in the output tray 102 has reached the Sow stack zone 214.

[00333 The first optical sensor 212-1 , in response to receiving no light from an optical source 210, is to indicate presence of media in the low stack zone 214 of the output tray 102. in an example, in response to the first optical sensor 212- 1 receiving no light from the optical source 210 and the second and third optical sensors 212-2 and 212-3 receiving Sight, it may be indicated that media in the output tray 102 is present up to the low stack zone 214. The first optical sensor 212-1 on receiving light from the optical source 210 is to indicate absence of media in the iow stack zone 214. The second optical sensor 212-2, in response to receiving no Sight from the optica! source 210, is to indicate presence of media in a middie stack zone 216 of the output tray 102. In an example, the middle stack zone 216 corresponds to a medium ievel of media, such as 21 to 40 numbers of ordinary A4 sheets, being present in the output fray 102. in an example, in response to the first optical sensor 212-1 and the second optical sensor 212-2 receiving no light from the optica! source 210 and the third optica! sensor 212-3 receiving Sight from the optica! source 210, it may be indicated that media in the output tray 102 is present up to the middie stack zone 216. The second optical sensor 212-2, in response to receiving light from the optical source 210, indicates absence of media in the middle stack zone 216 of the output tray 102 The third optical sensor 21 -3, in response to receiving no Sight from the optical source 210, is to indicate presence of media in a high stack zone 218 of the output tray 102. in an example, the high stack zone 218 corresponds to a high level of media, such as 41 to 60 numbers of ordinary A4 sheets, being present in the output tray 102. Further, in response to ali the optical sensors, vl2. the first optical sensor 212-1 , the second optical sensor 212-2, and the third optical sensor 212-3 receiving no Sight from the optica! source 210, it may be indicated that media in the output tray 102 is present up to the high stack zone 218. The third optical sensor 212-3 on receiving light from the optical source 210 indicates absence of media in the high stack zone 218,

100343 The imaging device 200 includes a Sight blocking element 106 mounted on the first segment 202 of the output tray 102. As can be seen from Figs 2a and 2b, the light blocking element 106 is positioned between the optical source 210 and the optical sensor array 104. In an example, the light blocking element 108 is made from a plastic material and may be formed integral to the first segment 202 of the output tray 102. in an example, the light blocking element may be mounted on the first segment 202 and may be affixed to the first segment 202 by use of mechanical fasteners, such as clamps, screws, etc. With reference to Fig. 2a, the Sight blocking element 108, depicted in grey color, is solid and optically opaque which blocks passage of light through the light blocking element 108. The tight blocking element 106 includes a U-shaped slot 220 which is a through-passage which may allow light to pass through it

[00363 In the retracted position of the output tray 102, the Sight blocking element 106 is aligned with the optical sensor array 104, as illustrated through Fig. 2c, With reference to Fig. 2c, the first optica! sensor 212-1 and the third optical sensor 212-3 are positioned such that they receive light from the optical source through the slot 220 of the light blocking element 106. Light from the optical source towards the second optical sensor 212-2 is blocked by the Sight blocking element 106 and hence the second optical sensor 212-2 does not receive Sight from the optical source 210. Thus, in the retracted position of the output tray 102, the light blocking element 106 blocks the second optical sensor 212-2 for receiving Sight from the optica! source 210 and keeps the first optical sensor 212-1 and the third optical sensor 212-3 unblocked for receiving light from the optical source 210 though the slot 220. As shown in Fig. 2b, in the refracted position of the output tray 102, radiations 222 from the optical source 210 are received by the first and third optical sensors 212-1 and 212-3, and radiations 222 travelling towards the second optical sensor 212-2 are blocked at the Sight blocking element 106. in an example, the slot 220 may have varying structures that enable passage of light to the first optical sensor 212-1 and the third optical sensor 212-3 white passage of light to the second optical sensor 212-2 remains blocked

0036| The imaging device 200 includes a position detection module 108 which is coupled to the optical sensor array 104. The position detection module 108 can analyze output signals of the optical sensor array 104 to determine position of the output tra 102. Based on the determined position of the output tray 102, the position defection module 108 may also generate control signals for operation of the imaging device 200.

[00373 Fig. 3a illustrates a schematic diagram of the imaging device 200 with the output tray 102 in the extended position, in accordance with an example Fig 3b illustrates a cross-sectional view of the imaging device 200 with the output tray 102 in the extended position, in accordance with an example.

[0Q38J In the extended position of the output tray 102, the first segment is in a second position and a portion‘X’ of the first segment 202 protrudes out of the imaging device 200, as illustrated in Fig. 3a. The second segment 206 is fully extended.

[00393 The output tray 102 may be moved from the retracted position to the extended position by drawing out the output tray 102 from the slot 204 in the direction as indicated by arrow E. The first segment 202 may he mounted on a channel (not shown) on both sides of the output tray 102. Sides of the first segment 202 may be held within the channel allowing the first segment to be slidably moved along the channel when the output tray 102 is moved between the retracted position and the extended position.

[00403 In an example, the second segment 208 may be coupled to the first segment 202 such that the second segment may slidably move in and out of the first segment 202. The first segment 202 and the second segment 206 are configured such that the frictional force which opposes movement of the first segment 202 from the first position to the second position is greater that the frictionai force which opposes movement of the second segment 208 from an unextended position to a fully extended position. Thus, when the output tray 102 is putted in the direction of arrow E to move the output tray 102 from the retracted position to the extended position, the second segment 208 moves to the fully extended position prior to the first segment 202 being move from the first position to the second position.

[0041] As the first segment 202 moves to the second position, as illustrated in Fig. 3a, the Sight blocking element 106 mounted on the first segment 202 also moves in the direction of arrow Έ\ As the light blocking element 106 moves in the direction of Έ\ the Sight blocking element 106 unblocks the optical sensor array 104 for receiving light from the optical source 210. in the extended position of the output tray 102 , light from the optica! source 210 can travel through the slot 220 of the tight blocking element 106 and may be received by the optical sensor array 104.

[0042] Thus, in the extended position of the output tray 102, the light blocking element 106 is positioned such that, the slot 220 is aligned with the optica! sensor array 104. The alignment of the light blocking element 106 with respect to the optical sensor array 104 is illustrated through Fig. 3c. With reference to Fig 3c, the first optical sensor 212-1 , the second optical sensor 212- 2, and the third optical sensor 212-3 are positioned such that they receive light from the optical source (not shown in Fig. 3c) through the slot 220 of the light blocking element 106. Thus, no light from the optical source 210 is blocked by the light blocking element 106 in the extended position of the output tray 102. As shown in Fig. 3b, in the extended position of the output tray 102, radiations 222 from the optical source 210 travel through the light blocking element 106 and are received by the first, second and third optica! sensors 212-1, 212-2, and 212-3 of the optica! sensor array 104.

100431 In operation, when a print command is received b the imaging device 200, the position detection module 108 analyzes an output signal of the optica! sensor array 104. The position detection module 108 identifies that the output tray 102 is in the retracted position, in response to the output signal corresponding to the first optical sensor 212-1 receiving light from the optical source 210, the second optical sensor 212-2 receiving no light from the optical source 210, and the third optical sensor receiving light from the optical source

210.

£00443 Upon determining that the output tray 102 is in the retracted position, the position detection module 108 may delay execution of the print command until the output tray 102 is moved to the extended position in an example, upon determining that the output tray 102 is in the refracted position, the position detection module 108 may generate a notification. The notification, for instance, may be displayed on a display unit of the imaging device 200 to alert the user that the print command may not be executed as the output tray 102 is in the retracted position in an example, the notification may also be an audio alert, such as a‘beep ⁵ sound, indicating that the execution of the print command is pending. The notification may also prompt the user to move the output tray 102 from the retracted position to the extended position

[00453 When the output tray is moved from the retracted position to the extended position, the light blocking element unblocks the optica! sensor array 104 for receiving light fro the opticai source 210, in a manner as explained with reference to Figs. 3a to 3c. In the extended position of the output tray 102, all the sensors of the optical sensor array 104 receives light from the opticai source 210 The position detection module 108 identifies that the output tray 102 is in the extended position, in response to the output signal of the optical sensor array 104 corresponding to ai! the sensors of the opticai sensor array 104 receiving tight from the optical source 210. Upon determining that the output tray 102 is in the extended position, the position detection module 108 may generate control signals to initiate the pending print command. Thus, print commands are executed once if is ensured that the output tray 102 is in the extended position which prevents spilling out of printed media from the imaging device 200 and curling and/or deforming of printed media discharged from the imaging device 200

[00463 Fig. 4 illustrates a schematic block diagram of an imaging device 400, in accordance with an example. The imaging device 400 includes an output tray 402 movable between an extended position and a retracted position. The output tray 402 is movable, in directions as indicated by arrow W, between the extended position and the retracted position. The output tray 402 may be similar to the output tray 102, as described earlier.

[0047] The imaging device 400 includes the optical sensor array 104 to detect a stack height of media in the output tray 402. The optical sensor array 104 includes the first optical sensor 212-1 a second optical sensor 212-2, and a third optical sensor 212-3. In an example, the optical sensor array 104 may receive Sight from an optical source, such as the optical source 210, present within the imaging device.

[0048] The first optical sensor 212-1 in response to receiving no Sight from the optica! source, is to indicate presence of media in a tow stack zone of the output tray 402. The second optical sensor 212-2, in response to receiving no light from the optica! source, is to indicate presence of media in a middle stack zone of the output tray 402. The third optical sensor 212-3, in response to receiving no light from the optica! source, is to indicate presence of media in a high stack zone of the output tray 402.

[0049] The imaging device 400 includes a Sight blocking element 404 coupled to the output tray 402. The light blocking element 404 is configured to block the second optical sensor 212-2 for receiving light from the optica! source, when the output tray 402 is in the retracted position. In an example, the light blocking element may be similar to the light blocking element 108.

|0QS£»3 The imaging device 400 also includes the position detection module 108 coupled to the optical sensor array 104. The position detection module 108 can determine, based on an output signal of the optical sensor array 104, the output tray 402 to be in one of the extended position and the retracted position 0051] Fig. 5 illustrates a schematic block diagram of an imaging device 500, in accordance with an example. The imaging device 500 includes an output tray 502 movable between an extended position and a retracted position. The output tray 502 can be moved between the extended position and the retracted position by moving the output tray 502 in directions as indicated by arrow W. The output tray 502 includes the first segment 202 and the second segment 206. In the retracted position of the output tray 102, the first segment 202 is in a first position and remains completely inside the imaging device 500, as shown in Fig. 5. in the extended position of the output tray 102, the first segment 202 is in a second position and a portion of the first segment 202 protrudes out of the imaging device 500. The output tray 502 may be similar to the output tray 102, as described earlier,

[00523 The imaging device 500 includes an optica! sensor array 504-1 to 504-N to detect a stack height of media in the output tray 502 in an example, the optica! sensor array may be similar to the optica! sensor array 10 . in an example, the optical sensor array 504-1 to 504-N may receive light from an optical source, such as the optica! source 210, present within the imaging device.

[0053] The imaging device 500 includes a light blocking element 506 mounted on the first segment 202. The light blocking element 506 is to block an optical sensor of the optical sensor array 504-1 to 504-N when the output tray 102 is in the refracted position in an example, the light blocking element 506 may be similar to the Sight blocking element 106. The imaging device 500 further includes a position detection module 108 coupled to the optical sensor array 504-1 to 504- N The position detection module 108 can determine the output fray 502 to be in one of the extended position and the retracted position, based on an output signal of the optical sensor array 504-1 to 504-N.

[00543 Figs. 6a and 6b illustrate examples of a Sight blocking element. Fig. 6a illustrates a light blocking element 600. The light blocking element 600 may be mounted on the output tray 102 and may perform similar functions as that of the light blocking element 106 as described in the description of Figs 1 to 3c. The light blocking element 600, depicted in grey color, may perform similar functions as that of the light blocking element 106. in an example, the light blocking elements 106, 404, and 504 may have a structural configuration similar to the light blocking element 600

[00553 Fig. 6b illustrates a light blocking element 602. The light blocking element 602 may be mounted on the output tray 102 and may perform similar functions as that of the light blocking element 106 as described in the description of Figs. 1 to 3c. The light blocking element 802, depicted in grey color, may perform similar functions as that of the light blocking element 108. In an example, the light blocking elements 108, 404, and 506 may have a structural configuration similar to the light blocking element 602. Although three example shapes and designs of the light blocking elements have been illustrated, the light blocking element may be formed in a variety of other shapes and designs.

[00563 Although implementations of present subject matter have been described in language specific to structural features and/or methods, it is to be noted that the present subject matter is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained in the context of a few implementations for the present subject matter.