Imaging devices, such as a printer may be employed to print content on a variety of print media. The imaging devices may include additional functions, such as scanning, and/or photocopying of the print media. Generally, the imaging device includes a print mechanism that prints the content on the print media, a compartment that stores the print media for scanning, and a feeding mechanism that feeds the print media from the compartment along a travel path to the print mechanism where the print media is printed. The travel path is a path that the print medium traverse from the compartment to the print mechanism.
The detailed description is provided with reference to the accompanying figures, wherein:
A feeding mechanism of an imaging device may include a roller that picks the print medium and another roller that feeds the picked print medium to the print mechanism. The feeding mechanism may implement a technique known as tailgating to maintain a predetermined gap between two consecutive print media to ensure that a throughput of the imaging device is maintained while ensuring that there is no overlap of the print media sheet that can cause jamming of the imaging device. Further, in order to maintain the gap between two consecutive print media, the feeding mechanism may employ various techniques. For example, in one technique, the imaging device may include different types of sensors with various capabilities including the ability to detect movement of the print medium inside the imaging device. In another technique, as an example, the feeding mechanism may include a set of rollers which may rotate at a fixed speed to pick the print media at predetermined time intervals. However, some imaging devices may be designed to vary a speed at which the print medium is fed to the printing mechanism, for instance, the print medium may not move at a constant speed along the travel path. Accordingly, the gap between the consecutive print media may vary and the latter type of feeding mechanisms discussed above may be unable to cater to such an operation of the imaging device.
On the other hand, in the feeding mechanisms that uses sensors, an array of sensors may be used for detecting the movement of the print medium moving towards the print mechanism. Generally, the feeding mechanism may initiate pick-up of the next print medium once the array of sensors indicates that the print medium has passed through. In other words, the array of sensors can track exact movements of the print medium and, accordingly, provide for a well-regulated movement of the print medium along the travel path. While such sensor-based mechanisms may cater to the varying speed of the print media, such mechanisms may be complex in construction and operation, owing to the use of array of sensors and their data. As a result, the imaging devices using the array of sensors may be expensive to manufacture and operate. Moreover, the use of array of sensors may make the imaging device prone to failure owing to the complexity. For instance, any fault in one sensor from the array of sensor may cause failure of the entire feeding mechanism.
Examples of techniques of adjusting a gap between consecutive print media are described. According to an aspect, the present subject matter involves use of a reference position, referred as to a homing position, along a travel path and tracking movement of print media along the travel path for adjusting the gap between the consecutive print media. Accordingly, as an example, the movement of a print medium may be tracked using a low-cost, low capability sensor which can identify passage of an edge of the print medium. Such a detection by the sensor combined with tracking of an operation of the imaging device may be used, in said example, to detect whether the print medium has reached the homing position, which acts as a reference to pick the next print medium. Thereafter, the gap between the consecutive print media can be adjusted, and then, the movement of the two consecutive print media can be so controlled to ensure that the gap between them is maintained. For example, a rate of movement of the picked print medium is regulated based on a rate of movement of the print medium preceding it for adjusting the gap as well as maintaining the gap.
According to an example, a print medium is picked up by a pick-up roller of the imaging device while a transfer roller of the imaging device feeds a preceding print medium to a print mechanism of the imaging device. Motions of the pick-up roller and the transfer roller may be desynchronized to allow pick-up and also to adjust a gap between the picked print medium and the preceding print medium. Further, once the gap is adjusted, motions of the pick-up roller and the transfer roller may be synchronized so that the picked print medium may be moved by the pick-up roller and the transfer roller towards the print mechanism until the arrival of the picked print medium at a homing position. In one example, arrival at the homing position is determined based on a length of travel path traversed by the picked print medium. Further, the length of travel path traversed by the picked print medium may be determined by detecting a leading edge of the picked print medium as the print medium traverse the travel path and the motion exhibited by the transfer roller thereafter. As mentioned previously, the leading edge may be detected using the sensor.
Upon arrival of the picked print medium at the homing position, motions of the pick-up roller and the transfer roller may be desynchronized again, and a subsequent print medium may be picked by the pick-up roller. Simultaneously, the transfer roller may feed the print medium towards the print medium. Moreover, the motion of the pick-up roller may be varied to adjust a gap between the print medium being fed towards the print mechanism and the subsequent print medium, for example, based on a motion of the transfer roller for moving the print medium with respect to the print mechanism for creating markings on the print medium. In one example, creating the marking can be injecting ink on the print medium to create the markings. Further, as explained above, once the gap has been adjusted, the gap is then maintained by synchronizing the motion of the pick-up roller and the transfer roller again.
In one example, as part of adjusting the gap, the gap between the consecutive print media can be reduced. In said example, the rotational speed of the pick-up roller may be increased and, accordingly, a time between an end of the printing operation on the preceding print medium and beginning of a printing operation on the subsequent print medium can be low. In another example, the gap between the consecutive print media can be increased, and accordingly, the rotational speed of the pick-up roller may be reduced. Such a gap adjustment can be done, for example, to prevent overlapping of print media or for preventing jamming.
Further, since the imaging devices based on the present subject matter uses a low-cost sensor to manage the gaps, the manufacturing cost, operational cost, and maintenance cost associated with the imaging device is low. Moreover, the imaging device of the present subject matter does not include complex components thereby making the imaging device less prone to failures, owing to fewer parts.
In the illustrated example, the use of the terms “preceding print medium” and the “subsequent print medium” does not indicate a predefined order. Further, the term “preceding” is does not indicate a first page of a printing operation. Instead, in this context, the terms “preceding print medium” and “subsequent print medium” merely indicate a consecutive relationship between individual media.
The above aspects are further described in conjunction with the figures, and in associated description below. It should be noted that the description and figures merely illustrate principles of the present subject matter. Therefore, various implementations that encompass the principles of the present subject matter, although not explicitly described or shown herein, may be devised from the description and are included within its scope. Additionally, the word “coupled” is used throughout for clarity of the description and can include either a direct connection or an indirect connection.
The imaging device 102 based on the present subject matter may receive instructions from one of the user devices 104, 106, 108, and 110 over the communication network 112 to print content on print media stored in the imaging device 102. In one example, the instructions may include parameters regarding the print media, for instance, the size, on which the markings are to be formed. In addition, the instructions may include margins for the print media. Upon receipt of the instructions, the imaging device 102 may commence formation of markings on a print medium. In one example, formation of markings may include injecting ink on the print medium. In the illustrated example, the imaging device 102 may use of a reference position, referred as to a homing position, along a travel path and tracking movement of print media along the travel path for adjusting the gap between the consecutive print media. Further, the movement of a print medium may be tracked using a sensor which can identify passage of an edge of the print medium. Further, detection of the arrival of the print medium at the homing position may act as a reference to pick the next print medium. Thereafter, the gap between the consecutive print media can be adjusted and may be maintained. For example, a rate of movement of the picked print medium is regulated based on a rate of movement of the print medium preceding it for adjusting the gap as well as maintaining the gap. The construction and operation of the imaging device 102 is explained with respect to
According to an example, the pick-up roller 202 may pick the print media stored in an input tray 210. Further, the transfer roller 204 may receive the print media from the pick-up roller 202 and move the picked print media along a travel path. The travel path may be a path that the print media traverse from the input tray to a print mechanism. Furthermore, the sensor 206 may detect an edge, for instance, a leading edge of the print medium as the print medium travels past the sensor 206. The controller 208 may obtain information from the sensor 206 and use it regulate the operation of the pick-up roller 202 and the transfer roller 204 to adjust a gap between consecutive print media, such as a first medium and a second medium from the print media. In the illustrated example, the use of the term “first print medium” and the “second print medium” does not indicate a predefined order. Further, the term “first” is does not indicate a first page of a printing operation. Instead, in this context, the terms “first print medium” and “second print medium” merely indicate a consecutive relationship between individual media.
For instance, upon detecting the passage of the leading edge of the first print medium, the sensor 206 may generate a detection signal. In turn, the controller 208 may receive the detection signal which can trigger the controller 208 to determine if the first print medium has arrived at the homing position. Based on the determination, the controller 208 may regulate the rotational speeds of the pick-up roller 202 and the transfer roller 204, to initiate the pick-up of the second print medium by the pick-up roller 202 as well as to adjust the gap between the first and the second print medium. For instance, the controller 208 may regulate the rotational speeds of the pick-up roller 202 and the transfer roller 204 in order to adjust a gap between the first print medium and the second medium. In one example, a de-skew operation on the print medium may be performed while at the homing position. In another example, the formation of the markings on the print medium by the print mechanism commence at the homing position.
In operation of the controller 208, the determination engine 214 can determine when the first print medium, travelling on the travel path, arrives at the homing position. As mentioned above, such a determination can be initiated in response to the sensor 206 detecting the passage of the leading edge of the first print medium, such as upon receipt of the detection signal by the determination engine 214. Reception of the detection signal may be used, for instance, by the controller 208 to begin tracking a degree of movement of the medium subsequent to the position of the medium at which the edge is detected. Thereafter, the determination engine 214 may measure a degree of rotation of the transfer roller 204 to determine whether the first print medium has arrived at the homing position. Further, the adjustment engine 216 that may vary a gap between the second print medium and the first print medium after the first print medium has arrived at the homing position. For instance, the adjustment engine 216 may adjust a gap between a leading edge of the second print medium and a trailing edge of the first print medium, for instance, by regulating a rotational speed of the pick-up roller 202, with due consideration to the rotational speed of the transfer roller 204. Once the gap is adjusted, the adjustment engine 216 may maintain a constant gap between the first and the second print media.
As mentioned above, in operation of the imaging device 102, the controller 208 may obtain information from the sensor 206 and use it to regulate the operation of the pick-up roller 202 and the transfer roller 204 to adjust a gap between consecutive print media, such as a first medium and a second medium from the print media. In addition, the controller 208 can control the pick-up roller 202 to pick the print media stored in an input tray 210 and move the print media to the transfer roller 204 and control the transfer roller 204 to move the picked print media along the travel path towards the print mechanism (not shown). The transfer roller 204, for instance, may be installed downstream with respect to the pick-up roller 202 along the travel path and the imaging device 102 may include a plurality of idle rollers 306 placed along the travel path to facilitate movement of the print medium 308, along the travel path.
For instance, the pick-up roller 202 may be in contact with a stack of print media in the input tray 304 and may pick up the print medium placed at the top of the stack. Furthermore, the pick-up roller 202 may pick up the print medium upon receipt of a command by the controller 208 from a user device for forming markings on the print media. Accordingly, the controller 208 can regulate the pick-up roller 202 to move the print medium to the transfer roller 204 along the travel path. In an example, the pick-up roller 202 may be coupled to a variable-speed motor which is controlled by the controller 208 to move the print media along the travel path and to also regulate the motion of the print media along the travel path. Similarly, the transfer roller 204 may also be coupled to a variable-speed motor controlled by the controller 208 to move the print medium to the print mechanism and then move the print medium with respect to the print mechanism based on the markings to be formed on the print medium. For example, the variable-speed motor can be any one of a servo motor and a stepper motor. Further, the pick-up roller 202 and the transfer roller 204 may be provided with similar or different kinds of variable-speed motors.
Further, the sensor 206 may be installed along the travel path, for instance, at any position along the travel path, such that a distance between the sensor 206 and the transfer roller 204 is known. In one example, the imaging device 102 may be installed proximate to the pick-up roller 202. In another example, the sensor 206 may be installed proximate to the transfer roller 204. The sensor 206 may be, as an example, an optical sensor and/or an infrared sensor. As mentioned previously, the sensor 206 may detect the leading edge or a trailing edge of the print medium as the print medium travels past the sensor 206, during operation of the imaging device 102. Accordingly, the sensor 206 may generate the detection signal upon detecting the edge and pass the detection signal to the controller 208 which may be triggered to determine when the first print medium arrives at the homing position.
The controller 208, in addition to the components discussed previously, includes a memory 314 having data 316, and interface(s) 318. Further, the engines 212, among other capabilities, may fetch and execute computer-readable instructions stored in the memory 314. The memory 314, communicatively coupled to the engines 212, may include a non-transitory computer-readable medium including, for example, volatile memory, such as Static Random-Access Memory (SRAM) and Dynamic Random-Access Memory (DRAM), and/or non-volatile memory, such as Read-Only-Memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes. Further, the data 316 may include parameter data 324 and other data 326. The other data 326 may include data generated and saved by the engines 212 to provide various functionalities to the imaging device 102.
Further, the engines 212 may additionally include a receiving engine 320 and other engine(s) 322. In one example, the receiving engine 320 may receive the detection signal and instructions to perform a printing operation. The other engine(s) 322 may provide functionalities that supplement applications or functions performed by the imaging device 102. Further, the adjustment engine 216 may regulate rotational speeds of the transfer roller 204 and the pick-up roller 202. For instance, the adjustment engine 216 may regulate the rotational speed of the transfer roller 204 based on printing parameters, such as a size of print media, and margins for the first print medium to form the markings. Accordingly, the rotational speed of the transfer roller 204 may be regulated.
As mentioned previously, the determination engine 214 may determine when the first print medium, travelling on the travel path, arrives at the homing position. The determination, by determination engine 214, may begin in response to reception of the detection signal from the sensor 206. Accordingly, after the leading edge of the first print medium has passed the sensor 206, from that point in time, the determination engine 214 can measure a degree of rotation of the transfer roller 204 to determine whether the first print medium has arrived at the homing position. In the meantime, after the detection signal has been received, the determination engine 214 may synchronize the motion of the pick-up roller 202 and the transfer roller 204 so as to allow a smooth movement of the first print medium which is achieved by the motion of the pick-up roller 202 and the transfer roller 204. In case where the pick-up roller 202 and the transfer roller 204 are of a same size, the determination engine 214 may match the rotational speeds of both the rollers 202, 204 to synchronize the motions. In another case where the pick-up roller 202 and the transfer roller 204 are of different sizes, the determination engine 214 may regulate the motion of the both the rollers 202, 204 in a way that the speed at which the first print medium moves along both the rollers 202, 204 is the same.
Further, upon determination of the arrival of the first print medium, the determination engine 214 of the controller 208 may desynchronize the motion of the pick-up roller 202 and transfer roller 204. The desynchronization of the motion, in an example, means that the pick-up roller 202 and the transfer roller 204 can exhibit independent motions, for instance, at different speeds. This may allow the pick-up roller 202 and the transfer roller 204 to perform disjunct functions at the same time, in contrast to the conjugated function of smoothly moving the first print medium to the print mechanism, where their motions are synchronized.
Accordingly, upon determining the arrival of the first print medium at the homing position the determination engine 214 may desynchronize the motions of the pick-up roller 202 and the transfer roller 204. For instance, the determination engine 214, after desynchronization, may control the pick-up roller 202 to pick the second print medium 408 from the input tray while at the same time, the transfer roller 204 can move the print medium, for example, based on the print parameters, for forming the markings. As explained above, the motions of the pick-up roller 202 and the transfer roller 204 are independent of each other and are based on the respective operation that they are performing.
Once the second print medium has been picked up, the adjustment engine 216 may then adjust the gap between the first print medium and the second print medium based on the motion of the transfer roller 204. For instance, the adjustment engine 216 control the pick-up roller 202, such that the gap between the consecutive print media can be reduced. In said example, the adjustment engine 216 may control the servo motor of the pick-up roller 202 to increase the rotational speed of the pick-up roller may be increased, such that a time between an end of the printing operation on the preceding print medium and beginning of a printing operation on the subsequent print medium is reduced. In another example, adjustment engine 216 may control the servo motor of the pick-up roller 202 to decrease the rotational speed, such that the gap between the consecutive print media can be increased.
Upon receipt of the detection signal, the determination engine 214 synchronizes motion of the pick-up roller 202 and the transfer roller 204, such that the rates at which the first print medium 402 is conveyed by the pick-up roller 202 and the transfer roller 204 are same. Meanwhile, the pick-up roller 202 and the idle rollers 306 moves the first print medium 402 towards the transfer roller 204 as shown in
According to an example, the determination engine 214 may determine when the first print medium 402 reaches the homing position. Knowledge of the homing position may be useful for a number of different purposes. For instance, the homing position can be a position where the leading edge of the first print medium 402 reaches the transfer roller 204, as shown in
In the illustrated example, the determination engine 214 may include information, such as a Length the Travel Path between the sensor and the homing position. Further, the Length the Travel Path may be pre-fed based on a design of the imaging device 102. As mentioned before, the determination engine 214 may determine arrival of the first print medium 402 at the homing position using the degree of rotation of the transfer roller 204 and the length of the path described by the first print medium. For instance, the determination engine 214 may determine a time at which the first print medium 402 arrives at the homing position after traversing the Length the Travel Path between the sensor 206 and the homing position based on the degree of rotation of the transfer roller 204.
In another example, the determination engine may determine the Length of the Travel Path based on a variety of parameters stored as parameter data 324 and using the formula:
Length of Travel Path=(L±B)−A−C±D±E
In yet example, the determination engine 214 may be reconfigured based on the parameters ‘D’ and ‘E’ and design related parameter ‘L’, ‘A’, and ‘C’ of the imaging device 102, if the Length of the Travel Path is known using the formula:
D+E=Length of Travel Path+(A+B+C)+L)
For instance, one of the parameters can be an offset ‘A’ between a position where printing operation is performed on the first print medium 402 and a position where printing operation is performed on the second print medium 408 owing to the difference in the margins for the first print medium 402 and the second print medium 408. Another parameter can be a maximum supportable length ‘L’ of the print medium and a difference ‘t B’ between the maximum supportable length and a prestored media length associated with the imaging device 102. Yet another parameter can be slippage ‘C’ of the print medium when the print medium is picked by the pick-up roller 202. According to an example, one parameter can be a predefined delay ‘D’ that the controller 208 may be configured to induce and another parameter can be a known reference point ‘±E’ along the length of the travel path. Further, the parameters ‘L’, ‘A’, ‘C’, and ‘D’ may be based on a design of the imaging device 102 while the parameters ‘D’ and ‘E’ may be varied.
According to an example, once the determination engine 214 determines the homing position, the determination engine 214 may desynchronize the motion of the pick-up roller 202 and the transfer roller 204, such that the rotational speed of the pick-up roller 202 and the transfer roller 204 may be independent of each other. Thereafter, the determination engine 214 may actuate the servo motor of the pick-up roller 202 to initiate the pick-up of the second print medium 408 from the input tray. Simultaneously, the determination engine 214 may control the servo motor of the transfer roller 204 to move the first print medium 402 towards the print area 312.
Further, the adjustment engine 216 may regulates the servo motor of the transfer roller 204 for regulating the movement of the first print medium 402 based on the received instructions. Simultaneously, the adjustment engine 216 may measure the rotational speed of the transfer roller 204 to synchronize the rotational speed of the pick-up roller 202 with the transfer roller 204 to maintain the predetermined gap 410 between a trailing edge 412 first print medium 402 and a leading edge 414 of the second print medium 408 as shown in
In one example, the adjustment engine 216 may vary the gap 410, for instance, reduces the gap 410. In such a case, the adjustment engine 216 may operate the servo motor of the pick-up roller 202 to increase the rotational speed of the pick-up roller 202 thereby reducing the gap 410 as shown in
Further, as the second print medium 408 moves along the travel path, the second print medium 408 moves past the sensor 206. As the second print medium 408 moves past the sensor 206, the sensor 206 detects the leading edge 414 of the second print medium 408. Once the leading edge 414 is detected, the controller 208 may operate in a way as explained before. Further, the same operation may be performed until the printing operation is completed.
The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to employ the method 1000, or an alternative method. Additionally, individual blocks may be deleted from the methods without departing from the spirit and scope of the subject matter described herein. Furthermore, the methods 1000 can be employed in any suitable hardware, software, firmware, or combination thereof. The method 1000 is explained with reference to the imaging device 102, however, the methods can be employed in other systems as well.
Referring to
Further, at block 1004, a position of the first print medium with respect to a homing position on the travel path may be detected. In one example, the determination engine 214 may determine the position of the first print medium by tracking the movement of the first print medium along the travel path. In addition, the determination engine 214 may also determine the homing position as explained above.
At block 1006, the second print medium 408 may be picked by the pick-up roller 202, in response of detecting that the position of the first print medium 402 is the homing position.
Finally, at block 1008, the gap 410 between the trailing edge 412 of the first print medium 402 and the leading edge 414 of the second print medium 408 by regulating the rotational speed of the pick-up roller 202 based on the rotational speed of the transfer roller 204.
The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to employ the method 1100, or an alternative method. Additionally, individual blocks may be deleted from the methods without departing from the spirit and scope of the subject matter described herein. Furthermore, the methods 1100 can be employed in any suitable hardware, software, firmware, or combination thereof. The method 1100 is explained with reference to the imaging device 102, however, the methods can be employed in other systems as well.
Initially, at block 1102, the pick-up roller 202 may pick the first print medium 402 to move the first print medium 402 (shown in
At block 1112, the determination engine 214 check if the first print medium has arrived at the homing position. In case the first print medium 402 has not arrived at the homing position, the method 1100 moves to block 1110. Further, in case the determination engine 214 determines that the first print medium 402 has arrived at the homing position, the method 1100 moves to block 1114. A manner by which the determination engine 214 determines when the first print medium 402 arrives at the homing position has already been explained before with respect
For example, the processing resource 1204 may be a processor of a computing system, such as the imaging device 102. The non-transitory computer readable medium 1202 may be, for example, an internal memory device or an external memory device. In one example, the communication link 1206 may be a direct communication link, such as one formed through a memory read/write interface. In another example, the communication link 1206 may be an indirect communication link, such as one formed through a network interface. In such a case, the processing resource 1204 may access the non-transitory computer readable medium 1202 through a network 1208. The network 1208 may be a single network or a combination of multiple networks and may use a variety of communication protocols.
The processing resource 1204 and the non-transitory computer readable medium 1202 may also be communicatively coupled to data sources 1210 over the network 1208. The data sources 1210 may include, for example, databases and computing devices. The data sources 1210 may be used by the database administrators and other users to communicate with the processing resource 1204.
In one example, the non-transitory computer readable medium 1202 includes a set of computer readable and executable instructions, such as the engines 212. The set of computer readable instructions, referred to as instructions hereinafter, may be accessed by the processing resource 1204 through the communication link 1206 and subsequently executed to perform acts for network service insertion.
For discussion purposes, the execution of the instructions by the processing resource 1204 has been described with reference to various components introduced earlier with reference to description of
On execution by the processing resource 1204, the controller 208 may actuate the servo motor of the pick-up roller 202 to pick the first print medium 402. Further, the controller 208 may also synchronize the motion of the pick-up roller 202 and the transfer roller 204 as the first print medium moves along the travel path. In one example, the controller may detect a leading edge of the first print medium and generate a detection signal that may be used by the controller to synchronize the motion of the first print medium and the second print medium. Further, the controller 208 may determine when the first print medium arrived at the homing position. In one example, the controller 208 may determine when the first print medium arrived at the homing position based on the detection signal and motion of the transfer roller 204 as explained before. Further, the controller 208 may actuate the servo motor of the pick-up roller 202 to pick the second print medium 408 while at the same time, actuates the servo motor of the transfer roller 204 to feed the first print medium 402 to the print area. Finally, the controller 208 may adjust the gap between the leading edge of the second print medium 408 and the trailing edge of the first print medium 402 by regulating a rotational speed of the pick-up roller based on an instantaneous rotational speed of the transfer roller.
Although aspects for methods and systems for adjusting the gap between consecutive print medium have been described in a language specific to structural features and/or methods, the present subject matter is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples for adjusting the gap.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/023566 | 3/22/2019 | WO | 00 |