Patent Application
20230166499
This application claims priority from Japanese Patent Application No. 2021-194007 filed on Nov. 30, 2021. The entire content of the priority application is incorporated herein by reference.
Aspects of the present disclosure relate to a liquid ejection apparatus having a medium container configured to accommodate a sheet-like medium.
In an apparatus configured to eject liquid toward a sheet-like medium, the sheet-like medium may come into contact with a head configured to eject the liquid and the medium may be stained. As control for reducing the stain of the medium (hereinafter referred to as a stain reduction control), operation waiting times may be provided between ejection operations.
In a conventional stain reduction control, if the operation waiting time is long, the time required for the entire operation becomes too long, and if the operation waiting time is short, there is a possibility that the stain reduction effect cannot be secured. Therefore, the degree of the stain reduction control needs to be kept within a necessary and sufficient range according to the possibility of occurrence of stain as much as possible.
At least one aspect of the present disclosure is advantageous to provide one or more improved techniques to achieve a liquid ejection apparatus configured to execute the stain reduction control to a degree corresponding to the possibility of occurrence of stain.
According to aspects of the present disclosure, there is provided a liquid ejection apparatus including a medium container configured to accommodate a sheet-like medium, a liquid ejection head configured to execute an ejection operation of ejecting liquid, a mover configured to move the sheet-like medium fed from the medium container relative to the liquid ejection head, and a controller. The mover is configured to execute, among a first moving operation of moving the sheet-like medium in a first direction and a second moving operation of moving the liquid ejection head in a second direction orthogonal to the first direction, at least the first moving operation. The controller causes the liquid ejection head and the mover to alternately perform execution of the first moving operation and execution of the ejection and second moving operations or to simultaneously execute the ejection operation and the first moving operation, and adjusts at least one selected from the group of an amount of liquid to be ejected from the liquid ejection head in the ejection operation, a time interval between the start of the ejection operation and the start of the next ejection operation when alternately performing execution of the first moving operation and execution of the ejection and second moving operations, and a moving speed of the sheet-like medium by the first moving operation when simultaneously executing the ejection operation and the first moving operation, according to medium information relating to curling of the sheet-like medium and indicating one of or both a characteristic and usage condition of the sheet-like medium fed from the medium container so that contact of the sheet-like medium with the liquid ejection head is suppressed.
According to aspects of the present disclosure, there is further provided a liquid ejection apparatus including a medium container configured to accommodate a sheet-like medium, a liquid ejection head configured to execute an ejection operation of ejecting liquid, a mover configured to move the sheet-like medium fed from the medium container relative to the liquid ejection head, the mover including a first roller pair configured to move the sheet-like medium fed from the medium container along a first conveying direction while nipping the sheet-like medium, and a second roller pair configured to move the sheet-like medium moved by the first roller pair along the first direction while nipping the sheet-like medium downstream of the first roller pair in the first direction, and a controller. The mover is configured to execute, among a first moving operation of moving the sheet-like medium in a first direction and a second moving operation of moving the liquid ejection head in a second direction orthogonal to the first direction, at least the first moving operation. The controller causes the liquid ejection head and the mover to alternately perform execution of the first moving operation and execution of the ejection and second moving operations or to simultaneously execute the ejection operation and the first moving operation, and adjusts at least one selected from the group of an amount of liquid to be ejected from the liquid ejection head in the ejection operation, a time interval between the start of the ejection operation and the start of the next ejection operation when alternately performing execution of the first moving operation and execution of the ejection and second moving operations, and a moving speed of the sheet-like medium by the first moving operation when simultaneously executing the ejection operation and the first moving operation, according to whether the first roller pair and the second roller pair are both nipping the sheet-like medium or only one of the first roller pair and the second roller pair is nipping the sheet-like medium so that contact of the sheet-like medium with the liquid ejection head is suppressed.
According to aspects of the present disclosure, there is further provided a liquid ejection apparatus including a medium container configured to accommodate a sheet-like medium, a liquid ejection head configured to execute an ejection operation of ejecting liquid, a mover configured to move the sheet-like medium fed from the medium container relative to the liquid ejection head, and a controller. The mover is configured to execute a first moving operation of moving the sheet-like medium in a first direction and a second moving operation of moving the liquid ejection head in a second direction orthogonal to the first direction. The controller causes the liquid ejection head and the mover to alternately perform execution of the first moving operation and execution of the ejection and second moving operations, and adjusts one of or both an amount of liquid to be ejected from the liquid ejection head in the ejection operation, and a moving speed of the sheet-like medium by the first moving operation between the start of the ejection operation and the start of the next ejection operation, according to medium information relating to curling of the sheet-like medium and indicating one of or both a characteristic and usage condition of the sheet-like medium fed from the medium container so that contact of the sheet-like medium with the liquid ejection head is suppressed.
According to aspects of the present disclosure, there is further provided a liquid ejection apparatus including a medium container configured to accommodate a sheet-like medium, a liquid ejection head configured to execute an ejection operation of ejecting liquid, a mover configured to move the sheet-like medium fed from the medium container relative to the liquid ejection head, the mover including a first roller pair configured to move the sheet-like medium fed from the medium container along a first conveying direction while nipping the sheet-like medium, and a second roller pair configured to move the sheet-like medium moved by the first roller pair along the first direction while nipping the sheet-like medium downstream of the first roller pair in the first direction, and a controller. The mover is configured to execute a first moving operation of moving the sheet-like medium in a first direction and a second moving operation of moving the liquid ejection head in a second direction orthogonal to the first direction. The controller causes the liquid ejection head and the mover to alternately perform execution of the first moving operation and execution of the ejection and second moving operations, and adjusts one of or both an amount of liquid to be ejected from the liquid ejection head in the ejection operation, and a moving speed of the sheet-like medium by the first moving operation between the start of the ejection operation and the start of the next ejection operation, according to whether the first roller pair and the second roller pair are both nipping the sheet-like medium or only one of the first roller pair and the second roller pair is nipping the sheet-like medium so that contact of the sheet-like medium with the liquid ejection head is suppressed.
Hereinafter, a printer 100 as an illustrative embodiment according to aspects of the present disclosure will be described with reference to
As shown in
The feed tray 1 is disposed inside the housing 100a below the head 5. The feed tray 1 can be inserted into and removed from the housing 100a in the longitudinal direction through an opening 101 formed on a front wall of the housing 100a.
The feed tray 1 is configured to accommodate a roll body R and cut sheets Kp. The feed tray 1 may be capable of accommodating the roll body R and the cut sheets Kp at the same time, or may be capable of selectively accommodating either the roll body R or the cut sheets Kp. The feed tray 1 includes a roll body support 11 configured to support the roll body R and a placing surface 12 on which the cut sheets Kp are to be placed.
The roll body R is formed by winding a long sheet around an outer periphery of a cylindrical core member Rc. The cut sheet Kp is shorter than the long sheet constituting the roll body R and is, for example, of a standard size of A4 or B5. The maximum size of the cut sheet Kp that can be used in the printer 100 is A4.
A roll body sensor 71 is provided slightly behind the roll body support 11. The roll body sensor 71 can detect whether or not the roll body R is accommodated in the roll body support 11 of the feed tray 1. Specifically, the roll body sensor 71 detects that the roll body R is supported by the roll body support 11 by detecting a roll sheet Rp unwound from the roll body R. The detection result of the roll body sensor 71 is output to the controller 9.
The conveying mechanism 2 includes a feed roller 21, an intermediate roller pair 22, a conveying roller pair 23, a discharge roller pair 24, and a guide member 25.
The feed roller 21 feeds the roll sheet Rp unwound from the roll body R supported by the roll body support 11 or the cut sheet Kp placed on the placing surface 12 from the feed tray 1. In the following description, when the roll sheet Rp and the cut sheet Kp are not distinguished, they are referred to as a “sheet P.”
The feed roller 21 is configured to be rotated by driving of a feed motor 21a (see
A feed position sensor 72 is provided slightly behind the feed roller 21. The feed position sensor 72 can detect whether the sheet P is at a position where the sheet P can be fed by the feed roller 21. The detection result of the feed position sensor 72 is output to the controller 9.
The intermediate roller pair 22 includes a drive roller configured to be rotated by driving of an intermediate motor 22a (see
The conveying roller pair 23 includes a drive roller configured to be rotated by driving of a conveying motor 23a (see
When the conveying motor 23a and the discharge motor 24a are driven under the control by the controller 9, the rollers of the conveying roller pair 23 and the rollers of the discharge roller pair 24 rotate while nipping the sheet P and convey the sheet P forward in a conveying direction. The conveying roller pair 23 is disposed behind (upstream in the conveying direction of) the head 5, and the discharge roller pair 24 is disposed in front of (downstream in the conveying direction of) the head 5. The conveying roller pair 23 conveys the sheet P, which has been guided forward by the guide member 25, further forward toward the discharge roller pair 24. The discharge roller pair 24 conveys the sheet P, which has been conveyed forward by the conveying roller pair 23, further forward while nipping the sheet P, and discharges the sheet P onto the discharge tray 7.
A leading edge position sensor 81 is provided slightly behind the conveying roller pair 23. When a leading edge of the sheet P is detected, the leading edge position sensor 81 outputs the detection result to the controller 9. A timing at which the leading edge position sensor 81 detects the leading edge of the sheet P is adjusted so as to coincide or substantially coincide with a timing at which the leading edge of the sheet P reaches the conveying roller pair 23.
The cutter 3 is disposed between the rear end of the feed tray 1 and the intermediate roller pair 22. The cutter 3 includes, for example, a disc-shaped rotating blade and a driven blade. By driving a cutting motor 3a (see
The head 5 includes a plurality of nozzles 51 (see
The moving mechanism 6 includes two guide rails 61 and 62, and a carriage motor 63 (see
The discharge tray 7 is disposed inside the housing in front of the head 5 and above the feed tray 1. The discharge tray 7 can be inserted into and removed from the housing 100a in the longitudinal direction through the opening 102 formed on the front wall of the housing 100a. The sheet P on which an image has been recorded by the head 5 is accommodated in the discharge tray 7.
As shown in
The controller 9 controls the entire printer 100. As shown in
As shown in
The various pieces of fixed data stored in the ROM 92 include data indicating sizes of the cut sheet Kp, a path length along a conveying path of the sheet P from the cutter 3 to the conveying roller pair 23, a distance in the longitudinal direction from the conveying roller pair 23 to the discharge roller pair 24, and a distance in the longitudinal direction from the conveying roller pair 23 to the image recording position by the head 5. The various pieces of fixed data also include data indicating a relationship between the number of rotations of the conveying roller pair 23 and a length of the sheet P. In the control by the controller 9 which will be described below, the length of the sheet P conveyed by the conveying roller pair 23 is calculated based on the number of rotations of the conveying roller pair 23 indicated by the detection result of the rotary encoder 82 and the above-described data. The various pieces of fixed data further include data indicating tables shown in
The controller 9 may be one in which only the CPU 91 performs various processes, one in which only the ASIC 94 performs various processes, or one in which the CPU 91 and the ASIC 94 cooperate to perform various processes. The controller 9 may be one in which one CPU 91 performs processes independently, or one in which a plurality of CPUs 91 perform processes in a shared manner. The controller 9 may be one in which one ASIC 94 performs processes independently, or one in which a plurality of ASICs 94 perform processes in a shared manner.
The controller 9 causes the printer 100 to record an image on a sheet P based on a recording instruction transmitted from an external device (e.g., a PC or a smartphone) by a user. The image recording is performed by alternately and repeatedly performing a conveying process in which the sheet P is conveyed by the conveying mechanism 2 by a prescribed distance in the conveying direction, and a scanning process in which ink is ejected from a plurality of nozzles 51 of the head 5 to the ink ejection area shown in
Based on the detection results of the leading edge position sensor 81 and the rotary encoder 82, the controller 9 controls the image recording and the cutting of the roll sheet Rp while grasping the relative position of the sheet P with respect to the conveying roller pair 23 (hereinafter, a relative position with respect to the conveying roller pair will be simply referred to as a “relative position”). The relative position of the sheet P is acquired as follows. Based on the detection result of the rotary encoder 82, the controller 9 acquires the number of rotations of the conveying roller pair 23 from the timing when the leading edge position sensor 81 detects the leading edge of the sheet P to an arbitrary timing during which the sheet P is conveyed by the conveying roller pair 23. Based on the acquired number of rotations, the controller 9 acquires a length of the sheet P conveyed by the conveying roller pair 23 from the timing when the leading edge of the sheet P reaches (or substantially reaches) the conveying roller pair 23 to the arbitrary timing. Based on this length, the controller 9 acquires a position of the leading edge of the sheet P (the roller sheet Rp or the cut sheet Kp) with respect to the conveying roller pair 23, that is, the relative position of the leading edge of the sheet P.
For example, based on the relative position of the leading edge of the roll sheet Rp and the path length from the cutter 3 to the conveying roller pair 23 stored in the ROM 92, the controller 9 causes the cutter 3 to cut the roll sheet Rp at a timing when a length from the leading edge of the roll sheet Rp to the position of the cutter 3 just reaches the cut length. As another example, based on the relative position of the leading edge of the sheet P and the distance from the conveying roller pair 23 to the image recording position stored in the ROM 92, the controller 9 acquires a position on the sheet P where image recording is being performed at an arbitrary timing.
When recording an image on the sheet P, the sheet P may rise and come into contact with the head 5 when ink ejected from the head 5 reaches the sheet P, thereby causing the sheet P to become stained. The controller 9 executes the stain reduction control to suppress the occurrence of such a problem. The stain reduction control includes (1) a control to reduce the amount of ink ejected from the head 5, and (2) a control to provide a waiting time between successive scanning processes in the image recording. The controller 9 executes one of or both (1) and (2) as the stain reduction control when a preset execution condition is satisfied. The execution condition includes, for example, an elapse of a prescribed time since the previous execution, an instruction to execute the stain reduction control has been made by the user through a recording instruction from an external device, and the like.
In addition, the controller 9 adjusts parameters for the stain reduction control as follows based on various detection results input from the roll body sensor 71, the feed position sensor 72, the leading edge position sensor 81, and the rotary encoder 82. In order to adjust the parameters, the controller 9 performs the following sheet type determination process, cumulative used length acquisition process, and roller nipping state acquisition process based on the various detection results described above.
As the sheet type determination process, the controller 9 determines whether the sheet P fed from the feed tray 1 by the feed roller 21 is the roll sheet Rp or the cut sheet Kp. This determination is made based on the detection results of the roll body sensor 71 and the feed position sensor 72. Specifically, when the roll body sensor 71 detects that the roll sheet Rp is supported by the roll body support 11 and the feed position sensor 72 detects that the sheet P is positioned at the feed position, the controller 9 determines that the sheet P fed by the feed roller 21 is the roll sheet Rp. On the other hand, when the roll body sensor 71 detects that the roll sheet Rp is not supported by the roll body support 11 and the feed position sensor 72 detects that the sheet P is positioned at the feed position, the controller 9 determines that the sheet P fed by the feed roller 21 is the cut sheet Kp. The determination may be made based only on the detection result of the roll body sensor 71 indicating whether or not the roll sheet Rp is supported by the roll body support 11. Alternatively, the determination may be made based on whether the recording instruction transmitted from an external device instructs recording on the roll sheet Rp or the cut sheet Kp, in addition to or in place of the detection results of the roll body sensor 71 and the feed position sensor 72.
As the cumulative used length acquisition process, the controller 9 calculates a cumulative used length after the roll sheet Rp on the roll body support 11 is first unrolled and used. This calculation is performed based on the detection results of the roll body sensor 71, the leading edge position sensor 81, and the rotary encoder 82. Specifically, based on the detection results of the roll body sensor 71, the controller 9 determines that a state of the roll sheet Rp has changed from a state in which the roll sheet Rp is not supported by the roll body support 11 to a state in which the roll sheet Rp is supported by the roll body support 11. Thus, it is detected that the roll sheet Rp is first unrolled and used.
Then, based on the detection result of the rotary encoder 82, the controller 9 integrates a length of the roll sheet Rp conveyed by the conveying roller pair 23 after the roll sheet Rp is first unrolled and used up to an arbitrary timing. Based on the integration result, for example, the controller 9 calculates at least one of the following first to third cumulative used lengths.
The first cumulative used length is the cumulative used length up to the leading edge of the roll sheet Rp being conveyed by the conveying mechanism 2 at a certain timing. This cumulative used length corresponds to the integration result up to the point immediately before the leading edge of the roll sheet Rp at the certain timing reaches the conveying roller pair 23.
The second cumulative used length is the cumulative used length up to a trailing edge of the roll sheet Rp being conveyed by the conveying mechanism 2 at the certain timing. This cumulative used length corresponds to a value obtained by adding the cut length of the roll sheet Rp to the integration result up to the point immediately before the leading edge of the roll sheet Rp at the certain timing reaches the conveying roller pair 23.
The third cumulative used length is a cumulative used length up to a position where image recording is performed on the sheet P at a certain timing. This cumulative used length corresponds to a value obtained by adding a length from the leading edge of the sheet P to the position where image recording is performed at the certain timing to the integration result up to the point immediately before the leading edge of the sheet P under recording reaches the conveying roller pair 23. The position where image recording is performed is any position in the conveying direction within the ink ejection area in
As the roller nipping state acquisition process, the controller 9 determines, at an arbitrary timing during image recording, whether the sheet P is nipped by both of the conveying roller pair 23 and the discharge roller pair 24 or by only one of them. This determination is performed based on the detection results of the leading edge position sensor 81 and the rotary encoder 82. Specifically, the controller 9 determines whether the sheet P is nipped by both of the conveying roller pair 23 and the discharge roller pair 24 or by only one of them based on the relative position of the leading edge of the sheet P and the length of the sheet P (the length of the cut sheet Kp stored in the ROM 92 or the cut length of the roll sheet Rp).
The controller 9 adjusts the ink ejection amount in the above-described stain reduction control (1) based on the data indicating the table of
The degree of reduction of the ejection amount indicated by the ejection amount rate in the table of
The controller 9 acquires the ejection amount rate from the table in
The controller 9 further adjusts the length of the waiting time for the stain reduction control (2) based on the data indicating the table of
The waiting time shown in the table of
The controller 9 acquires the length of the waiting time from the table of
As described above, as the stain reduction control, one of or both (1) the control to reduce the amount of ink ejected from the head 5 and (2) the control to provide a waiting time between successive scanning processes in the image recording are executed. According to the control (1), since the amount of ink is reduced, the occurrence of the rise of the sheet P when ink ejected from the head 5 reaches the sheet P is suppressed. According to the control (2), since the waiting time is provided between scanning processes, even if the sheet P rises once by one scanning process, the rising is likely to be settled by the next scanning process. Therefore, the occurrence of stains on the sheet can be suppressed by either of the controls (1) and (2).
The ink ejection amount rate in the control (1) or the length of the waiting time in the control (2) is adjusted as a parameter of the stain reduction control based on the sheet type, the cumulative used length, and the roller nipping state. Among these, the sheet type corresponding to the characteristics of the sheet P and the cumulative used length corresponding to the use state of the sheet P are both information related to the degree of occurrence of curling in the sheet P. With respect to the sheet type, the roll sheet Rp is more likely to curl than the cut sheet Kp. With respect to the cumulative used length, considering the mode of use the roll sheet Rp, that is, the roll sheet Rp being used after being unrolled from the roll body R formed by winding a long sheet around the core member Rc, the roll sheet Rp tends to have a higher degree of curling as the cumulative used length increases. When curling of the sheet P occurs, the sheet P is likely to contact the head 5, and the risk of the contact increases as the degree of curling increases. Therefore, the stain reduction control according to the curling state is realized by adjusting the content of the stain reduction control according to the sheet type and the cumulative used length which are information related to the occurrence of curling as described above.
The roller nipping state affects the likeliness of contact of the sheet P being conveyed by the conveying roller pair 23 and the discharge roller pair 24 with the head 5. That is, when the sheet P is nipped by both of the conveying roller pair 23 and the discharge roller pair 24, the possibility of the sheet P coming into contact with the head 5 between the nipping positions by the two roller pairs is lower than when the medium is nipped by only one of the two roller pairs. Therefore, the stain reduction control to a degree corresponding to the possibility of occurrence of stain is realized by adjusting the content of the stain reduction control according to the nipping state of the two roller pairs.
The stain reduction control is performed according to the tables shown in
Another printer 200 as an illustrative embodiment according to aspects of the present disclosure will be described with reference to
The head 205 includes a plurality of nozzles 51 formed on a lower surface thereof and the driver IC 52. When the driver IC 52 is driven under the control by the controller 209, ink is ejected from the nozzles 51 and an image is recorded on the sheet P conveyed by the conveying mechanism 2 when passing through an image recording position opposed to the lower surface of the head 205.
While the head 5 of the printer 100 is of a serial type that ejects ink from the nozzles 51 while moving in the scanning direction, the head 205 of the printer 200 is of a line type that ejects ink from the nozzles 51 at a fixed position.
The controller 209 controls the entire printer 200. To the controller 209, like the controller 9, the feed motor 21a, the intermediate motor 22a, the conveying motor 23a, the discharge motor 24a, the cutting motor 3a, the driver IC 52, the roll body sensor 71, the feed position sensor 72, the leading edge position sensor 81, the rotary encoder 82 and the like are electrically connected. The operating speeds of the feed motor 21a, the intermediate motor 22a, the conveying motor 23a, and the discharge motor 24a are controlled by the controller 209. Thus, the controller 209 can control a conveying speed of the sheet P by the conveying mechanism 2.
Like the controller 9, the controller 209 includes the CPU 91, the ROM 92, the RAM 93, the ASIC 94 and the like. Various pieces of fixed data stored in the ROM 92 of the controller 209 includes, in place of the data indicating the tables shown in
The controller 209 causes the printer 200 to record and image on the sheet P based on a recording instruction transmitted from an external device (e.g., a PC or a smartphone) by a user. The image recording is performed by ejecting ink from the plurality of nozzles 51 of the head 205 at the same time as the conveying process of conveying the sheet P in the conveying direction by the conveying mechanism 2. The ink is ejected toward the sheet P moving in the conveying direction by being conveyed by the conveying mechanism 2.
The controller 209 executes, as the stain reduction control, (3) a control to reduce the conveying speed. That is, the controller 209 reduces the conveying speed of the sheet P in the image recording as compared with the case where the stain reduction control is not performed. In the stain reduction control, like the controller 9, the controller 209 executes the sheet type determination process, the cumulative used length acquisition process, and the roller nipping state acquisition process. Then, the controller 209 acquires the conveying speed from the table indicated by the data stored in the ROM 92 based on the determination and calculation results in the aforementioned processes, and controls the image recording so that the sheet P is conveyed at the acquired conveying speed. In the table, the conveying speed for “roll sheet” is slower than that for “cut sheet,” the conveying speed gets slower as the cumulative used length increases, and the conveying speed for “one roller” is smaller than that for “two rollers.” Each of the conveying speeds that can be acquired from the table is slower than that in the case where the stain reduction control is not performed. Thus, in the conveying process the sheet P, the conveying speed is reduced as compared with the case where the stain reduction control is not performed, the conveying speed is slower for “roll sheet” than that for “cut sheet,” the conveying speed gets slower as the cumulative used length increases, and the conveying speed for “one roller” is slower than that for “two rollers.”
According to the above-described configuration, the controller 209 executes (3) the control to reduce the conveying speed as the stain reduction control. Even if the sheet P once rises, the slower the conveying speed, the more likely the rising settles. Therefore, the occurrence of stain on the sheet can be suppressed. Since the conveying speed is reduced according to the sheet type and the cumulative used length, which are information related to occurrence of curling, the stain reduction control can be executed according to the state of curling. Since the conveying speed is reduced according to the roller nipping state by the two roller pairs, the stain reduction control can be performed to a degree corresponding to the possibility of occurrence of stain.
While the invention has been described in conjunction with various example structures outlined above and illustrated in the figures, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example embodiments of the disclosure, as set forth above, are intended to be illustrative of the invention, and not limiting the invention. Various changes may be made without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to embrace all known or later developed alternatives, modifications, variations, improvements, and/or substantial equivalents. Some specific examples of potential alternatives, modifications, or variations in the described invention are provided below:
[1] In the printer 100 described above, the stain reduction control (2) is performed by setting the waiting time between scanning processes to increase the time interval between the start of a scanning process and the start of the next scanning process. The stain reduction control of increasing the time interval may be performed by adopting other methods. For example, in the process of moving the carriage 4 from a position at the end of the scanning process to a position at the start of the next scanning process, a method of adjusting moving speed of the carriage 4 may be adopted. In this case, decreasing the moving speed corresponds to increasing the time interval. A method of adjusting the conveying speed of the sheet P in the conveying process executed between successive scanning processes (a process of conveying the sheet P by a predetermined distance in the conveying direction) may also be adopted. In this case, decreasing the conveying speed corresponds to increasing the time interval. In either method, by increasing the time interval between the start of a scanning process and the start of the next scanning process, even if the sheet P once rises by a scanning process, the lifting is likely to be settled by the next scanning process. Therefore, the occurrence of stain on the sheet P can be suppressed.
[2] In the printer 100 and 200 described above, the parameters are adjusted so that the effect of the stain reduction control becomes stronger for the roller nipping state of “one roller” than “two rollers.” In addition to or instead, the parameters of the stain reduction control may be adjusted according to which of the conveying roller pair 23 and the discharge roller pair 24 is nipping the sheet Pin the roller nipping state of “one roller.”
For example, in the case where the sheet P is the roll sheet Rp, considering the mode of use the roll sheet Rp, that is, the roll sheet Rp being used after being unrolled from the roll body R formed by winding a long sheet around the core member Rc, the curl is stronger at an upstream portion of the sheet P in the conveying direction. Therefore, in the case of one roll sheet Rp separated from the roll body R, the curl tends to be stronger in the vicinity of the trailing edge than in the vicinity of the leading edge in the conveying direction. A situation in which the sheet P is nipped by only the conveying roller pair 23 during image recording corresponds to a situation in which a portion of the one roll sheet Rp in the vicinity of the leading edge faces the head 5. On the other hand, a situation in which the sheet P is nipped by only the discharge roller pair 24 during image recording corresponds to a situation in which a portion of the one roll sheet Rp in the vicinity of the trailing edge faces the head 5. Therefore, the possibility that the sheet P comes into contact with the head 5 is higher when the sheet P is nipped by only the discharge roller pair 24 than when the sheet P is nipped by only the conveying roller pair 23.
Therefore, when the roller nipping state corresponds to “one roller,” it is preferable that the parameters are adjusted so that the contact of the sheet P with the head 5 is more suppressed when the sheet P is nipped by the discharge roller pair 24 disposed on the downstream side in the conveying direction (hereinafter referred to as “when the discharge rollers are nipping”) than when the sheet P is nipped by the conveying roller pair 23 disposed on the upstream side in the conveying direction (hereinafter referred to as “when the conveying rollers are nipping”). That is, it is preferable that the degree of reduction of the ejection amount is increased in the stain reduction control (1) of the printer 100 and that the waiting time is increased in the stain reduction control (2) of the printer 100 when the discharge rollers are nipping as compared with when the conveying rollers are nipping. In the stain reduction control (3) of the printer 200, it is preferable that the conveying speed of the sheet P is decreased when the sheet discharge rollers are nipping as compared with when the conveying rollers are nipping. It is thereby made possible to perform the stain reduction control to a degree corresponding to the possibility of occurrence of stain.
[3] Parameters may be adjusted based not only on the nipping state the sheet P being nipped by the conveying roller pair 23 and the discharge roller pair 24 but also on peripheral configurations that have influences on the state of the sheet P. For example, influences of a platen 40 and a corrugated plate 41 shown in
When the sheet P is conveyed by the conveying mechanism 2, the sheet P passes over the ribs 40a in the vicinity of the downstream of the conveying roller pair 23, and at the same time passes through the gap between the lower end of the corrugated plate 41 and the upper surface of the platen 40. At this time, the lower end of the corrugated plate 41 presses the sheet P downward, thereby causing the sheet P to curve downward. Furthermore, upper ends of the ribs 40a lift the sheet P upward, thereby causing the sheet P to curve upward. Thus, the sheet P takes a shape that waves in the scanning direction.
Because of the action of the platen 40 and the corrugated plate 41 on the sheet P, the sheet P maintains a stable shape in the vicinity of the downstream of the conveying roller pair 23. On the other hand, there is no configuration for stabilizing the shape of the sheet Pin the vicinity of the discharge roller pair 24. Therefore, when the sheet P is nipped by only the conveying roller pair 23, the sheet P is stably held only at and in the vicinity of the conveying roller pair 23. On the other hand, when the sheet P is nipped by only the discharge roller pair 24, the sheet P is stably held at and in the vicinity of the discharge roller pair 24 and is also relatively stably held in the vicinity of the conveying roller pair 23. Therefore, in the state in which the sheet P is nipped by only the conveying roller pair 23, the rising of the sheet P within an area between the conveying roller pair 23 and the discharge roller pair 24 is less suppressed than in the state in which the sheet P is nipped by only the discharge roller pair 24. Therefore, considering the action of the platen 40 and the corrugated plate 41 on the sheet P, when the roller nipping state is “one roller,” the stain reduction control to a degree corresponding to the possibility of occurrence of stain is realized by executing the stain reduction control so that the contact of the sheet P to the head 5 is more suppressed when the conveying rollers are nipping than when the discharge rollers are nipping.
When the effect of the corrugated plate 41 to stabilize the shape of the sheet P is relatively high, stain may be less likely to occur when the sheet P is not nipped by the discharge roller pair 24 and the sheet P is passing through the gap between the lower end of the corrugated plate 41 and the upper surface of the platen 40 than when the sheet P is nipped by only the discharge roller pair 24. In such a case, in the state in which the sheet P is nipped by only the discharge roller pair 24, the stain reduction control with a degree corresponding to the possibility of occurrence of stain is realized by executing the stain reduction control in such a manner that the contact of the sheet P to the head 5 is more suppressed than in the state in which the sheet P is not nipped by the discharge roller pair 24 and the sheet P is passing through the gap between the lower end of the corrugated plate 41 and the upper surface of the platen 40.
[4] According to the printers 100 and 200 described above, the parameters for the stain reduction control are adjusted according to at least one selected from the group of the sheet type, the cumulative used length, and the roller nipping state. Alternatively, or in addition, a configuration may be adopted in which the parameters are adjusted based on a detection result by a sensor that directly detects the degree of curling of the sheet P. Such a sensor may include, for example, an optical sensor provided on a side of the feeding path or the conveying path of the sheet P. The optical sensor detects how much the sheet P is rising or deviating from the correct path. Then, the controller 9 or 209 adjusts various parameters for the stain reduction control to values corresponding to the degree of the rise or deviation indicated by the detection result by the optical sensor.
[5] In the printer 100 described above, as the stain reduction control, one of or both (1) the control to reduce the amount of ink ejected from the head 5 and (2) the control to provide a waiting time between successive scanning processes in the image recording are executed. Alternatively or additionally, control for increasing resolution of image recording may be executed as the stain reduction control. When the resolution of image recording is increased, a larger number of so-called interlace processing and singling processing are executed according to the increase. As such, the ink ejection amount in one scanning process decreases and the conveying amount of the sheet P in one conveying process decreases. Thus, the rising of the sheet P is suppressed, and the possibility of the sheet P coming into contact with the head 5 is reduced, and as a result, the occurrence of stain on the sheet P is suppressed. In this control, the size of the resolution may be adjusted according to at least one selected from the group of the sheet type, the cumulative used length, and the roller nipping state. With the adjustment of the size of the resolution, both the degree of reduction of the ink ejection amount in one scanning process and the degree of reduction of the conveying amount of the sheet P in one conveying process are adjusted.
[6] The cases where aspects of the present disclosure are applied to the printers 100 and 200 have been described. However, aspects of the present disclosure can also be applied to a multi-function machine, a copier, or the like as long as it is an inkjet type image recording apparatus that ejects ink from a head.
The printer 100 and the printer 200 are examples of a “liquid ejection apparatus” according to aspects of the present disclosure. The longitudinal direction is an example of a “first direction” according to aspects of the present disclosure. The feed tray 1 is an example of a “medium container” according to aspects of the present disclosure. The cut sheet Kp is an example of a “short sheet-like medium” according to aspects of the present disclosure. The roll sheet Rp is an example of a “long sheet-like medium” according to aspects of the present disclosure. The sheet P is an example of a “sheet-like medium” according to aspects of the present disclosure. The conveying roller pair 23 is an example of a “first roller pair” according to aspects of the present disclosure. The discharge roller pair 24 is an example of a “second roller pair” according to aspects of the present disclosure. The conveying direction is an example of the “first direction” according to aspects of the present disclosure. The operation of the conveying mechanism 2 to convey the sheet P in the conveying direction with the conveying roller pair 23 and the discharge roller pair 24 is an example of a “first moving operation” according to aspects of the present disclosure. The head 5 and the head 205 are examples of a “liquid ejection head” according to aspects of the present disclosure. The operation of the head 5 to eject ink is an example of an “ejection operation” according to aspects of the present disclosure. The scanning direction is an example of a “second direction” according to aspects of the present disclosure. The moving mechanism 6 moving the head 5 in the scanning direction by moving the carriage 4 is an example of a “second moving operation” according to aspects of the present disclosure. The moving mechanism 6 and the above-described conveying mechanism 2 constitute a “mover” according to aspects of the present disclosure. The prescribed distance is an example of a “first length” according to aspects of the present disclosure. The same length as the prescribed distance in the conveying direction and the length different from the prescribed distance in the conveying direction are examples of a “second length” according to aspects of the present disclosure. The sheet type acquired by the following process is an example of “medium information indicating characteristics of the sheet-like medium” according to aspects of the present disclosure. The cumulative used length acquired by the following process is an example of “medium information indicating a usage state of the sheet-like medium” according to aspects of the present disclosure. The detection result by the optical sensor is an example of “medium information” according to aspects of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-194007 | Nov 2021 | JP | national |
