Inkjet recording apparatus

Abstract

To provide an inkjet recording device capable of suitably cleaning the surface of a conveying belt by reducing the amount of ink used for maintenance.SOLUTION: The controller of the inkjet recording apparatus is capable of executing the flushing operation of ejecting the ink from the ink ejection nozzles 521 that have not ejected the ink for a certain period of time or more at the time of non-image recording in which the ink is not ejected onto the sheet S, and executes the belt cleaning operation of ejecting the ink Ld onto the first conveyance belt 411 by executing the flushing operation and scraping off the ink Sd on the first conveyance belt 411 by the blade 44 when a predetermined period has elapsed after the conveyance abnormality of the sheet S is detected by the conveyance abnormality detector 43.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus. [Background technology]

[0002] Inkjet recording devices, which eject ink onto a recording medium such as paper to record an image, are widely used as recording devices such as printers and copiers because of their ability to record high-resolution images. Inkjet recording devices are equipped with a transport belt that transports the recording medium.

[0003] In such inkjet recording devices, if a recording medium transport error (jam) occurs, ink may not be ejected onto the recording medium but may be ejected onto the transport belt. To address this issue, a conventional technique for cleaning the transport belt is known.

[0004] For example, the liquid ejection device disclosed in Patent Document 1 performs a cleaning operation to clean the conveyor belt using a blade that is in contact with the conveyor belt. At this time, a preliminary ejection is performed in which liquid is ejected from the liquid ejection unit onto the conveyor belt in advance based on preset cleaning control information. This improves the sliding properties between the conveyor belt and the blade, and maintains the blade's cleaning function. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-86268 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional technology, liquid is discharged onto the conveyor belt based on cleaning control information that is preset for the cleaning operation of the conveyor belt, which has the problem of wasting liquid, which reduces the number of sheets that can be recorded onto the recording medium in the device, and there is a concern that the convenience of the device will decrease.

[0007] The present invention has been made in view of the above-mentioned points, and has as its object to provide an inkjet recording apparatus that can reduce the amount of ink used for maintenance and can suitably clean the surface of the conveyor belt. [Means for solving the problem]

[0008] In order to solve the above problems, the inkjet recording apparatus of the present invention includes a recording head, a conveyor belt, a blade, a transport abnormality detection unit, and a control unit. The recording head has an ink ejection surface on which a plurality of nozzles for ejecting ink onto a recording medium are formed. The conveyor belt is endless and disposed opposite the ink ejection surface to transport the recording medium. The blade scrapes off deposits adhering to the surface of the conveyor belt. The transport abnormality detection unit detects transport abnormalities of the recording medium passing between the ink ejection surface and the conveyor belt. The control unit controls the operation of the recording head and the conveyor belt. The control unit is capable of performing a flushing operation during non-image recording, in which ink is not ejected onto the recording medium, to eject ink from nozzles that have not ejected ink for a certain period of time or more. When a certain period of time has elapsed since the transport abnormality detection unit detected a transport abnormality of the recording medium, the control unit performs the flushing operation to eject ink onto the conveyor belt and then performs a belt cleaning operation to scrape off the ink on the conveyor belt with the blade. [Effects of the Invention]

[0009] According to the configuration of the present invention, the surface of the conveyor belt can be cleaned by utilizing a flushing (blank ejection) operation in which ink is ejected from the nozzles, which is performed to reduce and prevent nozzle clogging due to dried ink. In other words, ink flushing can simultaneously maintain the ejection performance of the print head and clean the belt. Therefore, the amount of ink used for maintenance can be reduced, and the surface of the conveyor belt can be suitably cleaned. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional front view of an inkjet recording apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the periphery of a recording unit of the inkjet recording apparatus of FIG. [Figure 3] FIG. 2 is a block diagram showing a schematic configuration of the inkjet recording apparatus of FIG. [Figure 4] FIG. 2 is a front view of the periphery of a recording unit of the inkjet recording apparatus of FIG. [Figure 5] 5 is a front view of the recording unit and its surroundings in FIG. 4, showing a state in which a sheet jam has occurred. FIG. [Figure 6] 5 is a front view of the recording unit and its surroundings in FIG. 4, showing a state in which ink that has been erroneously ejected onto the first conveyor belt has dried and solidified. FIG. [Figure 7] 5 is a front view of the recording unit and its surroundings in FIG. 4, showing a state where a belt cleaning operation is being performed. FIG. [Figure 8] 10 is a flowchart showing a processing example of a belt cleaning operation in the inkjet recording apparatus of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the following.

[0012] FIG. 1 is a schematic cross-sectional front view of an inkjet recording apparatus 1 according to an embodiment. FIG. 2 is a plan view of the periphery of a recording unit 5 of the inkjet recording apparatus 1 of FIG. 1. FIG. 3 is a block diagram showing a schematic configuration of the inkjet recording apparatus 1 of FIG. 1. The inkjet recording apparatus 1 is, for example, an inkjet recording printer. As shown in FIGS. 1, 2, and 3, the inkjet recording apparatus 1 includes an apparatus main body 2, a sheet supply unit 3, a sheet conveying unit 4, a recording unit 5, a drying unit 6, and a control unit 7.

[0013] The sheet supply unit 3 is disposed, for example, at the bottom of the apparatus main body 2. The sheet supply unit 3 stores a plurality of sheets (recording media) S, and separates and feeds the sheets S one by one during recording.

[0014] The sheet conveying unit 4 is disposed downstream of the sheet supplying unit 3 in the sheet conveying direction. The sheet conveying unit 4 conveys the sheet S sent out from the sheet supplying unit 3. The sheet conveying unit 4 conveys the sheet S to the recording unit 5 and the drying unit 6, and then discharges the sheet S after recording and drying to the sheet discharge unit 21. The sheet conveying unit 4 also has, for example, a reversing conveying unit 4r. When double-sided recording is performed, the sheet conveying unit 4 distributes the sheet S after recording and drying on the first side to the reversing conveying unit 4r, and then switches the conveying direction to reverse the sheet S and conveys it again to the recording unit 5 and the drying unit 6.

[0015] The sheet conveying unit 4 includes a first belt conveying unit 41 and a second belt conveying unit 42. The first belt conveying unit 41 has a first conveying belt (conveying belt) 411 formed in an endless shape. The second belt conveying unit 42 has a second conveying belt 421 formed in an endless shape. The first belt conveying unit 41 and the second belt conveying unit 42 suction-hold and convey the sheet S to the upper outer surfaces (upper surfaces) of the first conveying belt 411 and the second conveying belt 421, respectively. The first belt conveying unit 41 is disposed below the recording unit 5, facing an ink ejection surface 52a (described later) of the recording unit 5, and conveys the sheet S. The second belt conveying unit 42 is located downstream of the first belt conveying unit 41 in the sheet conveying direction, and is disposed in the drying unit 6 to convey the sheet S.

[0016] The recording unit 5 is located downstream of the sheet supply unit 3 in the sheet conveying direction, and is arranged opposite the first belt conveying unit 41. The recording unit 5 faces the sheet S that is attracted to and held on the upper surface of the first conveying belt 411 and conveyed, and is arranged above the first conveying belt 411 with a predetermined gap therebetween. In other words, the recording unit 5 faces the sheet S that is conveyed by the sheet conveying unit 4.

[0017] 2, the recording unit 5 holds head units 51B, 51C, 51M, and 51Y corresponding to four colors: black, cyan, magenta, and yellow. The head units 51B, 51C, 51M, and 51Y are arranged side by side along the sheet conveying direction Dc so that their longitudinal directions are parallel to the sheet width direction Dw, which is perpendicular to the sheet conveying direction Dc. Note that the four head units 51B, 51C, 51M, and 51Y have the same basic configuration, and therefore in the following description, the identification symbols "B," "C," "M," and "Y" representing each color may be omitted unless there is a particular need to limit them.

[0018] Each of the head units 51 for each color has a line-type inkjet recording head 52. In each of the head units 51 for each color, a plurality of recording heads 52 (for example, three (52a, 52b, 52c)) are arranged in a staggered pattern along the sheet width direction Dw.

[0019] The recording head 52 has an ink ejection surface 52a (see FIG. 4) at its bottom. A plurality of ink ejection nozzles (nozzles) 521 that eject ink onto the sheet S are formed on the ink ejection surface 52a. The plurality of ink ejection nozzles 521 are arranged in a line along the sheet width direction Dw, and can eject ink over the entire recording area on the sheet S. The recording unit 5 sequentially ejects ink from the recording heads 52 of the four color head units 51B, 51C, 51M, and 51Y toward the sheet S transported by the first transport belt 411, and records a full-color image or a monochrome image on the sheet S.

[0020] The drying unit 6 is disposed downstream of the recording unit 5 in the sheet conveying direction, and is provided with a second belt conveying unit 42. The sheet S, on which an ink image has been recorded in the recording unit 5, is adsorbed and held by the second conveying belt 421 in the drying unit 6, and the ink is dried while being conveyed. The sheet S, on which the image has been recorded and dried, and printing (recording) is complete, is discharged to a sheet discharge unit 21 provided on the top surface of the device main body 2.

[0021] The control unit 7 includes a CPU, an image processing unit, a memory unit, and other electronic circuits and electronic components (none of which are shown). The CPU controls the operation of each component provided in the inkjet recording apparatus 1 based on control programs and data stored in the memory unit to perform processing related to the functions of the inkjet recording apparatus 1. The sheet supply unit 3, the sheet conveying unit 4, the recording unit 5, and the drying unit 6 each receive individual commands from the control unit 7 and perform recording on the sheet S in cooperation with each other. The memory unit is configured by a combination of a non-volatile storage device such as a program ROM (Read Only Memory) or a data ROM, and a volatile storage device such as a RAM (Random Access Memory).

[0022] The control unit 7 can perform a flushing (blank ejection) operation at a timing different from the timing of ejecting ink onto the sheet S (during image recording), i.e., during non-image recording when ink is not being ejected onto the sheet S, to eject ink from the ink ejection nozzles 521 that have not ejected ink for a certain period of time or more. By performing the flushing operation, clogging of the ink ejection nozzles 521 due to dried ink can be reduced and prevented. This makes it possible to maintain the ejection performance of the recording head 52 in an optimal state.

[0023] Next, the configuration around the recording unit 5 will be described in more detail. Figure 4 is a front view of the recording unit 5 and its periphery in the inkjet recording apparatus 1 of Figure 1. For ease of explanation, ink Ld (droplet-shaped) ejected from the recording head 52 is depicted below the recording head 52 in Figure 4, but the ink actually ejected is much smaller than the ink Ld (droplet-shaped) depicted in Figure 4. The same is true for the ink Ld depicted in Figures 5, 6, and 7 (including the solidified ink Sd (approximately oval-shaped) in Figures 6 and 7).

[0024] As shown in FIG. 4, the sheet conveying section 4 further includes a conveyance abnormality detection section 43 and a blade 44.

[0025] The transport abnormality detection unit 43 includes a head upstream sensor 431 and a head downstream sensor 432. The head upstream sensor 431 is disposed upstream of the recording unit 5 in the sheet transport direction Dc and above the first belt transport unit 41. The head downstream sensor 432 is disposed downstream of the recording unit 5 in the sheet transport direction Dc and above the first belt transport unit 41. The head upstream sensor 431 and the head downstream sensor 432 are disposed opposite the sheet transport surface of the first transport belt 411.

[0026] The head upstream sensor 431 and the head downstream sensor 432 are sensors that detect whether the sheet S has reached the respective placement positions as it is transported from the upstream side to the downstream side of the first belt transport unit 41. Based on the detection signal of the sheet S received from the head upstream sensor 431, the control unit 7 controls the ink ejection operation from the ink ejection nozzles 521 for the sheet S that has reached a position opposite the recording heads 52 of each color by the first belt transport unit 41.

[0027] Furthermore, if the head downstream sensor 432 does not detect the sheet S within a certain period of time after the head upstream sensor 431 detects the sheet S, the control unit 7 determines that a transport abnormality (sheet jam) has occurred in the sheet S. That is, the transport abnormality detection unit 43 detects a transport abnormality in the sheet S passing between the ink ejection surface 52a of the recording head 52 and the first transport belt 411.

[0028] The blade 44 is disposed below the most downstream portion of the first conveyor belt 411 in the sheet conveying direction Dc. The blade 44 is an elastic member made of, for example, silicone resin or rubber, and formed into a plate shape. The blade 44 is disposed opposite the surface (outer peripheral surface) of the first conveyor belt 411 and contacts the surface with a predetermined pressure. The blade 44 extends along the sheet width direction and is longer than the first conveyor belt 411 in the sheet width direction. As the first conveyor belt 411 rotates, the blade 44 scrapes off any deposits adhering to the surface of the first conveyor belt 411.

[0029] A collection tray or the like may be placed below the blade 44 to collect the deposits scraped off from the first conveyor belt 411 by the blade 44.

[0030] Next, the belt cleaning operation of the first conveyor belt 411 will be described with reference to Figures 5, 6, and 7. Figures 5, 6, and 7 are front views of the recording unit 5 and its periphery in Figure 4, respectively, showing a state in which a sheet jam has occurred, a state in which ink Sd that has been erroneously ejected onto the first conveyor belt 411 has dried and solidified, and a state in which the belt cleaning operation is being performed.

[0031] 5, for example, if the sheet S is curved or bent, abnormal transport of the sheet S (sheet jam) occurs on the upstream side of the recording head 52 in the sheet transport direction Dc. The sheet S does not pass between the ink ejection surface 52a of the recording head 52 and the first transport belt 411. This may result in erroneous ejection of the ink Ld onto the first transport belt 411 instead of onto the sheet S, as shown in FIG.

[0032] If erroneous ejection of ink onto the first conveyor belt 411 goes unnoticed and is left unattended, the ink Sd will dry and solidify (see FIG. 6), making it difficult to easily remove the ink Sd from the first conveyor belt 411. Therefore, the control unit 7 executes a belt cleaning operation in which the blade 44 scrapes off the ink Sd on the first conveyor belt 411.

[0033] More specifically, during the belt cleaning operation, if a predetermined period of time has elapsed since the transport abnormality detection unit 43 detected a transport abnormality in the sheet S, the control unit 7 executes a flushing operation to eject the ink Ld onto the first transport belt 411 (see FIG. 7). The ink Ld is ejected onto the first transport belt 411 by the flushing operation, which is performed to maintain optimal ejection performance of the recording head 52. The ink Sd that has dried and solidified on the first transport belt 411 is melted by the ink Ld that is newly ejected by the flushing operation.

[0034] In this case, in order to promote melting of the dried and solidified ink Sd, a waiting time (melting period) for waiting for the next rotation of the first conveyor belt 411 may be provided.

[0035] Next, in the belt cleaning operation, the control unit 7 rotates the first conveyor belt 411 and scrapes off the ink Sd on the first conveyor belt 411 with the blade 44. The ink Sd that has dried and solidified on the first conveyor belt 411 has been melted by the newly ejected ink Ld, and can be easily scraped off and removed by the blade 44.

[0036] According to the above configuration, the surface (outer circumferential surface) of the first conveyor belt 411 can be cleaned by utilizing the ink flushing (blank ejection) operation, which is performed to reduce and prevent clogging of the ink ejection nozzles 521 due to dried ink. In other words, by flushing the ink, it is possible to simultaneously maintain the ejection performance of the recording head 52 and clean the first conveyor belt 411. Therefore, it is possible to reduce the amount of ink used for maintenance and to suitably clean the surface of the first conveyor belt 411.

[0037] Furthermore, the control unit 7 executes a flushing operation every time a predetermined number of images are recorded on the sheets S. The control unit 7 executes a belt cleaning operation every time the flushing operation is executed. More specifically, every time the control unit 7 executes a flushing operation, the control unit 7 rotates the first conveyor belt 411 and uses the blade 44 to scrape off ink ejected from the first conveyor belt 411 by the flushing operation.

[0038] According to the above configuration, the surface (outer peripheral surface) of the first conveyor belt 411 can be cleaned periodically in addition to when an abnormality in the conveyance of the sheet S occurs around the recording unit 5. Therefore, it is possible to maintain the ejection performance of the recording head 52 and the conveyance performance of the sheet S by the first conveyor belt 411 in an optimal state.

[0039] Next, there will be described an example of the flow of the belt cleaning operation in the inkjet recording apparatus 1. Fig. 8 is a flowchart showing an example of the processing of the belt cleaning operation in the inkjet recording apparatus 1 of Fig. 1.

[0040] When the inkjet recording apparatus 1 is powered on ("START" in FIG. 8), the control unit 7 determines whether a predetermined period of time has elapsed since the previous transport abnormality detection unit 43 detected a transport abnormality in the sheet S (step S101).

[0041] If a predetermined period of time has not elapsed since the abnormal transport of the sheet S was detected, or if no abnormal transport of the sheet S has been detected before (No in step S101), the control unit 7 proceeds to step S102. If a predetermined period of time has elapsed since the abnormal transport of the sheet S was detected (Yes in step S101), the control unit 7 proceeds to step S103.

[0042] In step S102, the control unit 7 determines whether the number of images recorded since the previous flushing operation has reached a predetermined number. If the number of images recorded since the previous flushing operation has not reached the predetermined number (No in step S102), the control unit 7 returns to step S101 and executes processing related to detection of a transport abnormality in the sheet S.

[0043] If a predetermined period of time has elapsed since the detection of a conveyance abnormality in the sheet S in step S101 (Yes in step S101), or if the number of images recorded since the previous flushing operation reaches a predetermined number in step S102 (Yes in step S102), the control unit 7 executes a flushing operation and starts a belt cleaning operation (step S103). That is, ink is ejected onto the first conveyor belt 411 by the flushing operation for maintaining the ejection performance of the recording head 52 in a suitable state.

[0044] Next, the control unit 7 rotates the first conveyor belt 411 and scrapes off the ink on the first conveyor belt 411 with the blade 44 (step S104). Then, the control unit 7 ends the processing related to the belt cleaning operation ("End" in FIG. 8).

[0045] The process relating to the belt cleaning operation shown in FIG. 8 is repeatedly executed while the inkjet recording apparatus 1 is in operation.

[0046] Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these, and various modifications can be made without departing from the spirit of the invention. [Industrial Applicability]

[0047] The present invention can be used in inkjet recording apparatuses. [Explanation of symbols]

[0048] 1. Inkjet recording device 4 Sheet transport section 5 Recording section 7 Control Unit 41 First belt conveyor 43 Transport abnormality detection unit 44 Blades 52 Recording head 52a Ink ejection surface 411 First conveyor belt (conveyor belt) 431 Head upstream sensor 432 Head downstream sensor 521 Ink ejection nozzle (nozzle) S sheet (recording medium)

Claims

1. a recording head having an ink ejection surface on which a plurality of nozzles for ejecting ink onto a recording medium are formed; an endless conveyor belt disposed opposite the ink ejection surface and conveying the recording medium; a blade for scraping off deposits adhering to the surface of the conveyor belt; a transport abnormality detection unit that detects a transport abnormality of the recording medium passing between the ink ejection surface and the transport belt; a control unit that controls the operation of the recording head and the conveyor belt; Equipped with the control unit is capable of executing a flushing operation during a non-image recording period in which ink is not ejected onto the recording medium, in which the control unit ejects ink from the nozzles that have not ejected ink for a certain period of time or more; An inkjet recording device characterized in that, when a predetermined period of time has elapsed since the transport abnormality detection unit detected a transport abnormality in the recording medium, the flushing operation is performed to eject the ink onto the transport belt, and a belt cleaning operation is performed to scrape off the ink on the transport belt with the blade.

2. 2. The inkjet recording apparatus according to claim 1, wherein the control unit executes the flushing operation every time a predetermined number of images are recorded on the recording medium, and executes the belt cleaning operation every time the flushing operation is executed.

Images