This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2021-141437 filed Aug. 31, 2021, the entire contents of which are hereby incorporated by reference.
The present disclosure relates to an inkjet recording device that ejects ink from ink ejection nozzles of a recording head so as to perform recording.
As a recording device such as a facsimile machine, a copier, or a printer, an inkjet recording device is widely used, which ejects ink from the nozzles of the recording head to form an image, so that a high definition image can be formed.
Such an inkjet recording device has a problem that paper dust generated from a paper sheet as a recording medium may clog the nozzle and cause a nozzle ejection failure (missing dot), resulting in lowering of image quality.
An inkjet recording device according to an aspect of the present disclosure includes a conveying unit, a recording unit, a device main body, and a control unit. The conveying unit includes a conveyor belt and a sheet sucking unit, so as to convey a paper sheet. The conveyor belt is endless and has many air holes for sucking air. The sheet sucking unit is disposed inside a loop of the conveyor belt, and includes a fan for sucking air through the air holes and a fan drive motor for rotating the fan, so as to suck and hold the paper sheet on the conveyor belt. The recording unit includes a recording head disposed to face an outer circumference surface of the conveyor belt, so as to eject ink from ink ejection nozzles of the recording head to the paper sheet sucked and held on the conveyor belt. The device main body houses the conveying unit and the recording unit. The control unit controls the conveying unit and the recording unit. The control unit is capable of executing a paper dust removing mode during image non-recording time, in which it rotates the fan drive motor by a power higher than that when conveying the paper sheet, so as to remove paper dust in the device main body.
Hereinafter, an embodiment of the present disclosure is described with reference to the drawings.
As illustrated in
In addition, a first sheet conveying path 4a is formed inside the printer 100. The first sheet conveying path 4a is positioned on the upper right side of the sheet feed cassette 2a. i.e. on the left side of the manual sheet feeding tray 2b. The paper sheet P sent out from the sheet feed cassette 2a passes through the first sheet conveying path 4a and is conveyed vertically upward along the side of the printer main body 1. The paper sheet sent out from the manual sheet feeding tray 2b passes through the first sheet conveying path 4a and is conveyed substantially horizontally to the left.
A registration roller pair 13 is disposed at a downstream end of the first sheet conveying path 4a in the sheet conveying direction. Further, the first belt conveying unit (conveying unit) 5 and the recording unit 9 are disposed near the registration roller pair 13 on the downstream side. The registration roller pair 13 corrects a skew of the paper sheet P, and sends out the paper sheet P to the first belt conveying unit 5 in synchronization with an ink ejection operation by the recording unit 9.
In addition, between the registration roller pair 13 and the first belt conveying unit 5, there is disposed a contact image sensor (CIS) 20 as a sheet detection sensor for detecting an end position of the paper sheet P in a width direction (in a direction perpendicular to the sheet conveying direction).
The first belt conveying unit 5 includes an endless first conveyor belt 8 (see
A first sheet sucking unit 30 is disposed at a position facing a backside of the carrying surface 8a of the first conveyor belt 8, inside the loop of the first conveyor belt 8. The first sheet sucking unit 30 has many holes 30a formed in the upper surface for sucking air. A first fan 30b is disposed inside the first sheet sucking unit 30, and it can suck air downward through the upper surface. In addition, the first conveyor belt 8 also has many air holes 8b for sucking air (see
As illustrated in
Each of the line heads 11C to 11K includes three recording heads 17a to 17c arranged in a zigzag manner, in the sheet width direction (the up and down direction in
The recording heads 17a to 17c constituting each of the line heads 11C to 11K are supplied with ink of the corresponding color among four colors inks (cyan, magenta, yellow, and black color inks), which are respectively stored in ink tanks (not shown).
Each of the recording heads 17a to 17c can eject ink through the ink ejection nozzles 18 corresponding to print positions in accordance with image data received from an external computer or the like, to the paper sheet P conveyed while sucked and held on the carrying surface 8a of the first conveyor belt 8. In this way, the cyan, magenta, yellow, and black color inks are superimposed so that a color image is formed on the paper sheet P on the first conveyor belt 8. Note that the printer 100 can also record a monochrome image.
On the downstream side (the left side in
The second belt conveying unit 12 includes an endless second conveyor belt 40 stretched around a second drive roller 41 and a second driven roller 42. The second conveyor belt 40 is driven by the second drive roller 41 to turn in a counterclockwise direction in
A second sheet sucking unit 43 is disposed at a position facing a backside of a carrying surface 40a of the second conveyor belt 40, inside the loop of the second conveyor belt 40. The second sheet sucking unit 43 has many holes 43a formed in the upper surface for sucking air. A second fan 43b is disposed inside the second sheet sucking unit 43, and it can suck air downward through the upper surface. In addition, the second conveyor belt 40 also has many air holes for sucking air (not shown). With the structure described above, the second belt conveying unit 12 conveys the paper sheet P while sucking and holding the same on the carrying surface 40a of the second conveyor belt 40. Note that although not shown here, the second sheet sucking unit 43 is also connected to the exhaust duct 31, so the air sucked by the second sheet sucking unit 43 passes through the exhaust duct 31 and the dust collecting filter 33, and is discharged to outside of the printer main body 1.
In addition, a conveyance guide part 50 is disposed at a position facing the carrying surface 40a of the second conveyor belt 40. The conveyance guide part 50 and the carrying surface 40a of the second conveyor belt 40 constitutes a sheet conveyance path together with the carrying surface 40a of the second conveyor belt 40. The conveyance guide part 50 suppresses warping or fluttering of the paper sheet P sucked and held on the carrying surface 40a by the second sheet sucking unit 43.
A decurler unit 14 is disposed downstream of the second belt conveying unit 12 in the sheet conveying direction and in a vicinity of the left side of the printer main body 1. The paper sheet P after the inks are dried in the second belt conveying unit 12 is sent to the decurler unit 14, which corrects a curl of the paper sheet P.
On the downstream side (the upper side in
In addition, a maintenance unit 19 is disposed below the second belt conveying unit 12. When performing maintenance of the recording heads 17a to 17c, the maintenance unit 19 moves to below the recording unit 9, wipes ink pushed out (purged) from the ink ejection nozzles 18 of the recording heads 17a to 17c (see
The belt drive motors 21 and 22 respectively drive the first drive roller 6 and the second drive roller 41 to rotate, so that the first conveyor belt 8 and the second conveyor belt 40 can turn. The fan drive motors 23 and 24 respectively drive the first fan 30b of the first sheet sucking unit 30 and the second fan 43b of the second sheet sucking unit 43 to rotate.
The operation panel 27 is an operation unit for receiving various setting inputs. For instance, by operating the operation panel 27, a user can input a size of the paper sheets P set in the sheet feed cassette 2a, i.e. information of a size of the paper sheet P that is conveyed by the first conveyor belt 8. In addition, by operating the operation panel 27, the user can also input the number of the paper sheets P to be printed or instruct start of a print job. In addition, the operation panel 27 also has a function as a notification device for notifying about an operating state (image recording mode or a paper dust removing mode described later) of the printer 100.
The storage unit 28 is a memory for storing an operation program of a control unit 110 and various sets of information, and it includes a read only memory (ROM), a random access memory (RAM), a nonvolatile memory, and the like. The information set by the operation panel 27 is stored in the storage unit 28.
The communication unit 29 is a communication interface for communicating information with an external device (such as a personal computer (PC)). For instance, when the user operates the PC and sends a print command with image data to the printer 100, the image data and the print command are input to the printer 100 via the communication unit 29. In the printer 100, a main control portion 110a controls the recording heads 17a to 17c to eject ink on the basis of the image data, so that an image can be recorded on the paper sheet P.
In addition, the printer 100 according to this embodiment includes the control unit 110. The control unit 110 is constituted of a central processing unit (CPU) and a memory, for example. Specifically, the control unit 110 includes the main control portion 110a, a sheet suction control portion 110b, a sheet supply control portion 110c, and a maintenance control portion 110d.
The main control portion 110a controls operations of individual units in the printer 100. For instance, drive of each roller in the printer 100, ink ejection from the recording heads 17a to 17c when recording an image, and the like are controlled by the main control portion 110a. The sheet suction control portion 110b sends a control signal to the fan drive motors 23 and 24 so as to control rotations of the first fan 30b and the second fan 43b, and thus a state of the paper sheet P sucked and held on the first conveyor belt 8 or the second conveyor belt 40 can be controlled. In addition, the sheet suction control portion 110b controls rotations of the first fan 30b and the second fan 43b, so as to perform the paper dust removing mode described later.
The sheet supply control portion 110c is a recording medium supply control portion that controls the registration roller pair 13 as a recording medium supply unit. For instance, the sheet supply control portion 110c controls the registration roller pair 13 based on a detection timing of a rear end of the paper sheet P by the CIS 20, and thus controls a conveyance timing of the following paper sheet P.
The maintenance control portion 110d controls the recording heads 17a to 17c to perform the purge operation described above in which the ink ejection nozzles 18 push out ink in a forced manner. When the maintenance control portion 10d controls the recording heads 17a to 17c to perform the purge operation, it also controls drive of the maintenance unit 19 described above (e.g. movement to below the recording unit 9 and retraction).
Note that the control unit 110 may further include a calculation portion that performs necessary calculation, and a time measuring portion that measures time. In addition, the main control portion 110a may also works as the calculation portion or the time measuring portion described above.
As described above, there is a problem that paper dust generated from the paper sheet P may clog the ink ejection nozzle 18 and cause an ink ejection failure (missing dot) of the ink ejection nozzles 18, resulting in lowering of image quality. Therefore, the printer 100 according to this embodiment performs the paper dust removing mode during image non-recording time, in which the first sheet sucking unit 30 and the second sheet sucking unit 43 are used for sucking paper dust floating in the printer main body 1.
In the paper dust removing mode, the fan drive motors 23 and 24 are driven to rotate by a power higher than that when conveying (sucking) the paper sheet P. For instance, when the power of the fan drive motor 23, 24 is expressed by a duty ratio, the duty ratio of the fan drive motor 23, 24 when conveying the paper sheet P is 50% to 70%, while the duty ratio of the fan drive motors 23 and 24 in the paper dust removing mode is 100% (maximum power).
As a result, the first fan 30b and the second fan 43b also rotate at a rotation speed higher than that when conveying the paper sheet P, and paper dust floating in the printer main body 1 is sucked by the first sheet sucking unit 30 and the second sheet sucking unit 43. The sucked paper dust passes through the exhaust duct 31 with air flow and is collected by the dust collecting filter 33.
By executing the paper dust removing mode, paper dust floating in the printer main body 1 can be reduced, and clogging of the ink ejection nozzles 18 due to paper dust can be suppressed. In addition, as the paper dust removing mode is performed while turning the first conveyor belt 8 and the second conveyor belt 40, paper dust adhered to perimeters of the first conveyor belt 8 and the second conveyor belt 40 can be sucked and removed, which is preferred.
Execution timing of the paper dust removing mode may be when image recording is finished, when the printer 100 is powered on or returned from a power saving (sleep) mode, when performing restoring operation (purge operation) of the recording heads 17a to 17c in which the ink ejection nozzles 18 push out thickened ink, or other timing.
Note that if the paper dust removing mode is performed every time when image recording is finished, an execution interval (interval) of the paper dust removing mode is shortened while print waiting time is increased, and hence image forming efficiency (productivity) is lowered. Therefore, the number of printed sheets (or printing time) is counted and accumulated, and the paper dust removing mode is performed every time when the number of printed sheets (or printing time) reaches a predetermined value. Thus, paper dust floating in the printer main body 1 can be reduced while suppressing the decrease in the image forming efficiency (productivity).
Duration time of the paper dust removing mode can be appropriately set in accordance with internal volume of the printer main body 1, execution timing of the paper dust removing mode, suction powers of the first sheet sucking unit 30 and the second sheet sucking unit 43 (maximum powers of the fan drive motors 23 and 24), and the like, and the duration time is preferably 30 seconds approximately. In addition, when executing the paper dust removing mode during the purge operation, the duration time is preferably shorter than time necessary for the purge operation, in order to decrease the print waiting time as much as possible.
The main control portion 110a determines whether or not a print command is received via the communication unit 29 from a host device such as a personal computer (Step S1). If the print command is not received (No in Step S1), a print waiting state is continued. If the print command is received (Yes in Step S1), the main control portion 110a starts printing on the paper sheet P (Step S2).
Specifically, the sheet supply control portion 110c controls the sheet feeding device 3a and the registration roller pair 13 to supply the paper sheet P to the first conveyor belt 8, and the sheet suction control portion 110b controls the first sheet sucking unit 30 to suck and hold the paper sheet P on the first conveyor belt 8. The main control portion 10a controls the recording heads 17a to 17c to eject ink to the paper sheet P in accordance with image data input via the communication unit 29. In addition, the main control portion 110a counts and accumulates the number of printed sheets n (Step S3).
Next, the main control portion 110a determines whether or not the printing is finished (Step S4). If the printing is not finished (No in Step S4), the process flow returns to Step S3, and the main control portion 110a continues ejecting ink to the paper sheet P and counting the number of printed sheets n. If the printing is finished (Yes in Step S4), the main control portion 110a determines whether or not the number of printed sheets n is a predetermined value N (such as 100) or larger (Step S5). If n<N is satisfied (No in Step S5), the process flow returns to Step S1, and the print waiting state is continued.
If n≥N is satisfied (Yes in Step S5), the paper dust removing mode is executed (Step S6). Specifically, the sheet suction control portion 110b sends a control signal to the belt drive motors 21 and 22, so that the first conveyor belt 8 and the second conveyor belt 40 can turn. In this state, the sheet suction control portion 110b sends a control signal to the fan drive motors 23 and 24, so as to drive the fan drive motors 23 and 24 to rotate by a power (such as the maximum power) higher than that when conveying (sucking) the paper sheet P. As a result, the first fan 30b and the second fan 43b also rotate at the maximum rotation speed, and paper dust floating in the printer main body 1 is sucked by the first sheet sucking unit 30 and the second sheet sucking unit 43.
Next, the main control portion 110a determines whether or not a predetermined time (e.g. 30 seconds) has elapsed from start of the paper dust removing mode (Step S7). If the predetermined time has not elapsed (No in Step S7), the paper dust removing mode is continued. If the predetermined time has elapsed (Yes in Step S7), turnings of the first conveyor belt 8 and the second conveyor belt 40, and rotations of the first fan 30b and the second fan 43b are stopped, and the paper dust removing mode is finished (Step S8). Then, after resetting the number of printed sheets n (n=0) (Step S9), the process flow returned to Step S1, and the print waiting state is continued.
According to the control example illustrated in
Note that in
In addition, in
Other than that, without limiting to the embodiment described above, the present disclosure can be variously modified within the scope the present disclosure without deviating from the spirit thereof. For instance, the number of the ink ejection nozzles 18 of the recording heads 17a to 17c, a space between the nozzles, and the like can be appropriately set in accordance with specification of the printer 100. In addition, the number of the recording heads is also not limited particularly. For instance, one, two, or four or more recording heads may be disposed for each of the line heads 11C to 11K.
In addition, the above embodiment describes the line head type printer 100 as the inkjet recording device, which performs recording with the line heads 11C to 11K, each of which includes the recording heads 17a to 17c having the many ink ejection nozzles 18 arranged in the sheet width direction, but the present disclosure can be similarly applied to a serial type inkjet recording device that performs recording with a recording head 17 that moves over the sheet.
The present disclosure can be used for inkjet recording devices that perform recording by ejecting ink from the ink ejection nozzles of the recording head. Using the present disclosure, it is possible to provide the inkjet recording device that can effectively remove paper dust generated from the paper sheet, with a simple structure.
Number | Date | Country | Kind |
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2021-141437 | Aug 2021 | JP | national |
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Number | Date | Country | |
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20230062349 A1 | Mar 2023 | US |