Cleaning device, image forming apparatus, and take-up control method

Abstract

To provide a cleaning device which can prevent generation of waste in a cleaning member, an image formation device and a winding control method.SOLUTION: A cleaning device comprises: a cleaning member which contacts a nozzle surface of a head unit that forms an image on a recording medium by an ink jet head, and cleans an ink remaining on the nozzle surface; a winding part which winds the cleaning member so that the cleaning member contacts the nozzle surface; a contamination state detection part which detects a contamination state of the cleaning member after cleaning; and a control part which so controls the winding part as to unwind the cleaning member according to the detected contamination state.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a cleaning device, an image forming apparatus, and a winding control method.

Background Art

[0002] Conventionally, there has been known an inkjet image forming apparatus that forms (records) an image on a recording medium by discharging ink from a plurality of nozzles provided in an inkjet head onto the recording medium conveyed by a conveying device.

[0003] The inkjet head of an inkjet image forming apparatus discharges ink from a plurality of nozzles. Pressure is individually applied to each nozzle, and ink discharge control corresponding to the image to be recorded is performed. The ink discharge ports of the nozzles are aligned and opened on one surface (nozzle surface) of the inkjet head facing the recording medium during image formation.

[0004] In an inkjet image forming apparatus having such a configuration, if foreign matter adheres to the nozzle surface, dried and thickened ink remains, or air bubbles are mixed in, good ink discharge for image formation cannot be performed. Therefore, head cleaning is performed to maintain a good ink discharge state.

[0005] As head cleaning, ink in the nozzles is discharged by pressurization from the upstream side of the nozzles or suction from the nozzle surface side, thereby removing (purifying) foreign matter, dried and thickened ink, and mixed air bubbles together with the discharged ink.

[0006] Also, after ink discharge as such a cleaning operation, etc., the ink remaining on the nozzle surface is cleaned (removed) by a wiping operation in which a wiping member (cleaning member) is brought into contact with and moved on the nozzle surface (see, for example, Patent Document 1). In the wiping operation, wiping members such as a wiper blade for scraping off ink and an absorbent sheet member are used.

[0007] In the technique described in Patent Document 1 above, when wiping the portion where the nip portion of the cap member contacts the nozzle surface of the recording head with a wiping member while relatively moving the recording head and the wiping unit, control is performed to wind the wiping member by a winding member.

Prior Art Document

Patent Document

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, in the technique described in Patent Document 1 above, since control is performed to wind the cleaning member (wiping member) without considering the amount of ink actually remaining on the nozzle surface, when the amount of ink is small, that is, when the amount of the cleaning member required for wiping the ink is small, more cleaning members than necessary are wound and used, resulting in waste of the cleaning member.

[0010] An object of the present invention is to provide a cleaning device, an image forming apparatus, and a winding control method capable of preventing waste of a cleaning member.

Means for Solving the Problems

[0011] The cleaning device according to the present invention is a cleaning member that contacts the nozzle surface of a head unit that forms an image on a recording medium by an inkjet head and cleans the ink remaining on the nozzle surface; a winding unit that winds the cleaning member so that the cleaning member contacts the nozzle surface; a dirt state detection unit that detects the dirt state of the cleaning member after cleaning; A control unit that controls the winding unit to wind back the cleaning member according to the detected dirt state; and the like.

[0012] The image forming apparatus according to the present invention, the above cleaning device, the head unit, and the like.

[0013] The winding control method according to the present invention, a cleaning member that contacts the nozzle surface of a head unit that forms an image on a recording medium by an inkjet head and cleans the ink remaining on the nozzle surface; a winding unit that winds the cleaning member so that the cleaning member contacts the nozzle surface, and a winding control method for a cleaning device, detecting the dirt state of the cleaning member after cleaning, and controlling the winding unit to wind back the cleaning member according to the detected dirt state.

Advantages of the Invention

[0014] According to the present invention, it is possible to suppress the occurrence of waste in the cleaning member.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0016] FIG. 1 is a diagram showing a schematic configuration of an inkjet image forming apparatus 1 (functioning as the "image forming apparatus" of the present invention). The inkjet image forming apparatus 1 includes a paper feeding unit 10, an image forming unit 20, a paper discharging unit 30, and a control unit 40 (see FIG. 3).

[0017] Under the control of the control unit 40, the inkjet image forming apparatus 1 conveys the recording medium P stored in the paper feeding unit 10 to the image forming unit 20, forms an image on the recording medium P in the image forming unit 20, and conveys the recording medium P on which the image is formed to the paper discharging unit 30. As the recording medium P, in addition to paper such as plain paper and coated paper, various media capable of fixing the ink landing on the surface, such as fabric or sheet-shaped resin, can be used.

[0018] The paper feeding unit 10 has a paper feeding tray 11 for storing the recording medium P and a medium supply unit 12 for conveying and supplying the recording medium P from the paper feeding tray 11 to the image forming unit 20. The medium supply unit 12 includes an annular belt supported by two rollers on the inside, and conveys the recording medium P from the paper feeding tray 11 to the image forming unit 20 by rotating the rollers with the recording medium P placed on the belt.

[0019] The image forming unit 20 includes a conveyance unit 21, a handover unit 22, a heating unit 23, a head unit 24, a fixing unit 25, a delivery unit 28, and the like.

[0020] The conveyance unit 21 holds the recording medium P placed on the conveyance surface 211a (placement surface) of the cylindrical conveyance drum 211, and performs a conveyance operation of conveying the recording medium P on the conveyance drum 211 in the conveyance direction (Y direction) by rotating around a rotation axis (cylindrical axis) along which the conveyance drum 211 extends in the X direction (perpendicular to the paper surface of FIG. 1).

[0021] The conveying drum 211 is provided with claw portions and air intake portions (not shown) for holding the recording medium P on its conveying surface 211a. The recording medium P is held on the conveying surface 211a by having its end pressed by the claw portions and being attracted to the conveying surface 211a by the air intake portions. The conveying unit 21 is connected to a conveying drum motor (not shown) for rotating the conveying drum 211. The conveying drum 211 rotates by an angle proportional to the rotation amount of the conveying drum motor.

[0022] The delivery unit 22 delivers the recording medium P conveyed by the medium supply unit 12 of the paper feeding unit 10 to the conveying unit 21. The delivery unit 22 is provided at a position between the medium supply unit 12 of the paper feeding unit 10 and the conveying unit 21, holds one end of the recording medium P conveyed from the medium supply unit 12 with the swing arm portion 221, picks it up, and delivers it to the conveying unit 21 via the delivery drum 222.

[0023] The heating unit 23 is provided between the arrangement position of the delivery drum 222 and the arrangement position of the head unit 24, and heats the recording medium P so that the recording medium P conveyed by the conveying unit 21 reaches a temperature within a predetermined temperature range. The heating unit 23 has, for example, an infrared heater or the like, and energizes the infrared heater based on a control signal supplied from the control unit 40 to cause the infrared heater to generate heat.

[0024] The head unit 24 discharges ink onto the recording medium P from ink discharge ports (nozzle openings) provided on a nozzle surface (ink ejection surface) facing the conveying surface 211a of the conveying drum 211 at an appropriate timing according to the rotation of the conveying drum 211 holding the recording medium P, thereby forming an image. The head unit 24 is arranged such that the nozzle surface and the conveying surface 211a are separated by a predetermined distance.

[0025] In the inkjet image forming apparatus 1 according to the present embodiment, four head units 24 corresponding to four colors of yellow (Y), magenta (M), cyan (C), and black (K) are arranged in the order of Y, M, C, K colors at predetermined intervals from the upstream side in the conveying direction of the recording medium P.

[0026] FIG. 2 is a schematic diagram showing the configuration of the head unit 24. Here, a nozzle surface 245 facing the conveyance surface 211a of the conveyance drum 211 in the head unit 24 is shown.

[0027] The head unit 24 includes four inkjet heads 242 attached to an attachment member 244. Each of the inkjet heads 242 is provided with a plurality of image forming elements (recording elements) each having a pressure chamber for storing ink, a piezoelectric element provided on the wall surface of the pressure chamber, and a nozzle 243. When a drive signal for deforming the piezoelectric element is input to this image forming element, the pressure chamber deforms due to the deformation of the piezoelectric element, the pressure in the pressure chamber changes, and ink is ejected from the nozzle 243 communicating with the pressure chamber.

[0028] In the inkjet head 242, two nozzle rows composed of nozzles 243 arranged at equal intervals in a direction intersecting the conveyance direction of the recording medium P (in the present embodiment, a direction orthogonal to the conveyance direction, that is, the X direction) are formed. These two nozzle rows are provided such that the arrangement positions of the nozzles 243 are shifted from each other in the X direction by half of the arrangement interval of the nozzles 243 in each nozzle row.

[0029] The four inkjet heads 242 are arranged in a staggered grid pattern so that the arrangement ranges in the X direction of the nozzle rows are continuously connected without interruption. The arrangement range in the X direction of the nozzles 243 included in the head unit 24 covers the width in the X direction of the region on the recording medium P where an image is formed and conveyed by the conveyance unit 21. The position of the head unit 24 is fixed with respect to the rotation axis of the conveyance drum 211 during image formation and used. That is, the head unit 24 has a line head capable of ejecting ink over the image forming width in the X direction with respect to the recording medium P, and the inkjet image forming apparatus 1 is an inkjet image forming apparatus of a single pass type.

[0030] Note that the number of nozzle rows of the inkjet head 242 may be not two but one or three or more. Also, the number of inkjet heads 242 of the head unit 24 may be not four but three or less or five or more.

[0031] As the ink ejected from the nozzles 243 of the image forming element, an ink containing a pigment is used. For example, white ink containing titanium dioxide or the like as a pigment is used. Also, as the ink ejected from the nozzles 243 of the image forming element, a gel ink containing a gelling agent, which undergoes a phase change between a gel state and a sol state depending on temperature and has the property of curing when irradiated with an energy ray such as ultraviolet light, is used. In the present embodiment, a gel ink containing a pigment is used as the ink ejected from the nozzles 243 of the image forming element.

[0032] The head unit 24 includes an ink heating unit (not shown) that heats the ink stored in the head unit 24. The ink heating unit operates under the control of the control unit 40 and heats the ink to a temperature at which it becomes a sol state.

[0033] The inkjet head 242 ejects the ink that has been heated to a sol state. When this sol-state ink is ejected onto the recording medium P, after the ink droplets land on the recording medium P, the ink quickly becomes a gel state and solidifies on the recording medium P by natural cooling.

[0034] The fixing unit 25 has a light emitting unit arranged across the width in the X direction of the conveying unit 21, and irradiates the recording medium P placed on the conveying unit 21 with an energy ray such as ultraviolet light from the light emitting unit to cure and fix the ink (gel ink) ejected onto the recording medium P. The light emitting unit of the fixing unit 25 is arranged to face the conveying surface 211a between the arrangement position of the head unit 24 and the arrangement position of the delivery drum 281 of the delivery unit 28 in the conveying direction.

[0035] The delivery unit 28 includes a cylindrical delivery drum 281 that transfers the recording medium P from the transport unit 21 to the belt loop 282, and a belt loop 282 having an annular belt whose inner side is supported by two rollers. The recording medium P transferred from the transport unit 21 onto the belt loop 282 by the delivery drum 281 is transported by the belt loop 282 and sent out to the paper discharge unit 30.

[0036] The paper discharge unit 30 has a plate-shaped paper discharge tray 31 on which the recording medium P sent out from the image forming unit 20 by the delivery unit 28 is placed.

[0037] In the inkjet image forming apparatus 1, if there is adhesion of foreign matter, residual of dried and thickened ink, or mixing of bubbles on the nozzle surface 245 where the nozzles 243 for discharging ink are formed, good ink discharge for image formation cannot be performed. Therefore, head cleaning is performed to maintain a good ink discharge state.

[0038] As head cleaning, by a purge operation that forcibly discharges the ink in the nozzles by pressurization from the upstream side of the nozzles or suction from the nozzle surface 245 side, foreign matter, dried and thickened ink, mixed bubbles, etc. are removed (purified) together with the discharged ink.

[0039] Also, after the ink discharge as such a cleaning operation, etc., the ink remaining on the nozzle surface 245 is cleaned by a wiping operation in which a cleaning member is brought into contact with and moved on the nozzle surface 245. In the wiping operation, absorbent sponge members, cloth members (e.g., cloth, non-woven fabric), or cleaning members such as rubber blades (blade members) that scrape off the ink are used.

[0040] FIG. 3 is a block diagram showing the main functional configuration of the inkjet image forming apparatus 1. The inkjet image forming apparatus 1 includes a heating unit 23, a head driving unit 241 and an inkjet head 242, a pressure contact / separation unit 246, a fixing unit 25, a control unit 40, a conveyance driving unit 51, an operation display unit 52, an input / output interface 53, a cleaning device 55, and a dirt state detection unit 90.

[0041] The head driving unit 241 supplies a driving signal that deforms a piezoelectric element in accordance with image data at an appropriate timing to the image forming element of the inkjet head 242, thereby ejecting an amount of ink corresponding to the pixel value of the image data from the nozzles 243 of the inkjet head 242.

[0042] The control unit 40 includes a CPU 41 (Central Processing Unit), a RAM 42 (Random Access Memory), a ROM 43 (Read Only Memory), and a storage unit 44.

[0043] The CPU 41 reads out various control programs and setting data stored in the ROM 43, stores them in the RAM 42, and executes the programs to perform various arithmetic processes. Further, the CPU 41 comprehensively controls the overall operation of the inkjet image forming apparatus 1.

[0044] The RAM 42 provides a working memory space for the CPU 41 and stores temporary data. The RAM 42 may include a non-volatile memory.

[0045] The ROM 43 stores various control programs and setting data to be executed by the CPU 41. Note that a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used instead of the ROM 43.

[0046] The storage unit 44 stores a print job (image formation command) input from the external device 2 via the input / output interface 53, image data related to the print job, and the like. Among these, the print job includes, in addition to information specifying the image data related to the image to be formed, information related to the type of the recording medium P on which the image is to be formed (for example, the size and thickness of the recording medium P). As the storage unit 44, for example, an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may be used in combination.

[0047] The conveyance drive unit 51 supplies a drive signal to the conveyance drum motor of the conveyance drum 211 based on a control signal supplied from the control unit 40 to rotate the conveyance drum 211 at a predetermined speed and timing.

[0048] Further, the conveyance drive unit 51 supplies a drive signal to the motors for operating the medium supply unit 12, the delivery unit 22, and the delivery unit 28 based on a control signal supplied from the control unit 40 to supply the recording medium P to the conveyance unit 21 and discharge it from the conveyance unit 21.

[0049] The operation display unit 52 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as operation keys and a touch panel arranged to overlap the screen of the display device. The operation display unit 52 causes the display device to display various information, and converts a user's input operation on the input device into an operation signal and outputs it to the control unit 40.

[0050] The input / output interface 53 mediates the transmission and reception of data between the external device 2 and the control unit 40. The input / output interface 53 is configured by, for example, any one of various serial interfaces, various parallel interfaces, or a combination thereof.

[0051] The external device 2 is, for example, a personal computer, and supplies a print job, image data, etc. to the control unit 40 via the input / output interface 53.

[0052] The cleaning device 55 cleans the ink remaining on the nozzle surface 245 by a wiping operation of moving the head unit 24 with the cleaning member 70 (see FIG. 4) in contact with the nozzle surface 245 of the head unit 24. In the present embodiment, an absorbent cloth member (e.g., cloth, non-woven fabric) is used as the cleaning member 70.

[0053] FIG. 4 is a diagram for explaining the specific configuration and operation of the cleaning device 55. As shown in FIG. 4, the cleaning device 55 includes a feeding roller 62, a winding roller 64 (functioning as the "winding unit" of the present invention), a cleaning member 70 stretched between the feeding roller 62 and the winding roller 64, and a dirt state detection unit 90. Note that the control unit 40 and the cleaning device 55 function as the "cleaning device" of the present invention.

[0054] The feeding roller 62 feeds the wound cleaning member 70 while rotating it under the control of the control unit 40. The winding roller 64 winds the cleaning member 70 fed by the feeding roller 62 while rotating it under the control of the control unit 40.

[0055] A backup member 61 for supporting the cleaning member 70 from below is provided between the feeding roller 62 and the winding roller 64. The backup member 61 is a member on a flat plate made of, for example, a porous body (e.g., porous ceramic, liquid-permeable resin) that can permeate air. The backup member 61 is parallel to the nozzle surface 245 of the head unit 24 and supports the cleaning member 70 in contact with the inside thereof so that the cleaning member 70 is parallel to the nozzle surface 245.

[0056] The pressing-separation part 246 (see FIG. 3) has a known configuration and, under the control of the control unit 40, presses (contacts) the nozzle surface 245 of the head unit 24 against the cleaning member 70 by moving the head unit 24 downward, or separates the nozzle surface 245 of the head unit 24 from the cleaning member 70 by moving the head unit 24 upward.

[0057] FIG. 4A shows a state before cleaning by the cleaning device 55. In this state, the control unit 40 controls the pressing-separation part 246 and separates the nozzle surface 245 of the head unit 24 from the cleaning member 70 by moving the head unit 24 upward. Ink 80 remains on the nozzle surface 245 of the head unit 24.

[0058] FIG. 4B shows a state in which cleaning by the cleaning device 55 is being performed. In this state, the control unit 40 controls the pressing-separation part 246 and presses the nozzle surface 245 of the head unit 24 against the cleaning member 70 by moving the head unit 24 downward.

[0059] In the present embodiment, in a state where the nozzle surface 245 is pressed against the cleaning member 70, the ink 80 remaining on the nozzle surface 245 is absorbed (adsorbed) by the cleaning member 70 and cleaned by a wiping operation (scrubbing operation) in which the cleaning member 70 is wound up by the take-up roller 64 to move the head unit 24.

[0060] The dirt state detection unit 90 is provided between the backup member 61 and the take-up roller 64 in the take-up direction of the cleaning member 70, and detects the dirt state of the cleaning member 70 after cleaning. In the present embodiment, the dirt state detection unit 90 irradiates light toward the cleaning member 70 after cleaning, receives the reflected light (for example, regular reflection light and diffuse reflection light), and outputs an electrical signal corresponding to the amount of the received reflected light. The dirt state detection unit 90 is a reflection-type optical sensor that optically detects the concentration of the ink 80 absorbed (adhered) onto the cleaning member 70 during cleaning to detect the dirt state of the cleaning member 70.

[0061] FIG. 4C shows a state after cleaning by the cleaning device 55. In this state, the control unit 40 controls the pressure contact separation unit 246 and moves the head unit 24 upward to separate the nozzle surface 245 of the head unit 24 from the cleaning member 70.

[0062] In the next cleaning by the cleaning device 55, the control unit 40 controls the pressure contact separation unit 246 and moves the head unit 24 downward to press the nozzle surface 245 of the head unit 24 against the cleaning member 70 (see FIG. 4B). Thereafter, in a state where the nozzle surface 245 is in contact with the cleaning member 70, a wiping operation (scrubbing operation) is performed in which the take-up roller 64 takes up the cleaning member to move the head unit 24, so that the ink 80 remaining on the nozzle surface 245 is absorbed (adsorbed) by the cleaning member 70 for cleaning (see FIG. 4B).

[0063] By the way, in the prior art (the technique described in Patent Document 1), since the control of taking up the cleaning member (wiping member) is performed without considering the actual amount of ink remaining on the nozzle surface, when the amount of the ink is small, that is, when the amount of the cleaning member required for wiping the ink is small, an excessive amount of the cleaning member is taken up and used, and as a result, there is a problem that the cleaning member is wasted.

[0064] Therefore, in the present embodiment, for the purpose of suppressing the occurrence of waste in the cleaning member, after the cleaning is completed, the control unit 40 controls the take-up roller 64 to rewind the cleaning member 70 according to the dirt state (the concentration of the ink 80) of the cleaning member 70 detected by the dirt state detection unit 90 (see FIG. 4D). Specifically, when the detected concentration of the ink 80 is equal to or lower than the threshold value, the control unit 40 rewinds the cleaning member 70, while when the detected concentration of the ink 80 is not lower than the threshold value, the control unit 40 controls not to rewind the cleaning member 70. By performing such control, when the amount of ink wiped off by the cleaning member 70 is small, that is, when the amount of the cleaning member 70 required for wiping off the ink is small, the wiped portion is rewound and reused for the next cleaning. As a result, it is possible to prevent an excessive amount of the cleaning member 70 from being taken up and used when the amount of ink wiped off by the cleaning member 70 is small, and thus to prevent the occurrence of waste in the cleaning member 70.

[0065] Next, the take-up control operation of the inkjet image forming apparatus 1 will be described. FIG. 5 is a flowchart showing an example of the take-up control operation of the inkjet image forming apparatus 1 (corresponding to the “take-up control method” of the present invention). Step S100 in FIG. 5 starts when an execution instruction for head cleaning occurs in the inkjet image forming apparatus 1.

[0066] First, the control unit 40 controls the pressure contact / separation unit 246 to move the head unit 24 downward so as to press the nozzle surface 245 of the head unit 24 against the cleaning member 70 (step S100).

[0067] Next, the control unit 40 controls the take-up roller 64 to start the take-up operation of the cleaning member 70 (step S120). Thereby, a wiping operation (scrubbing operation) for moving the head unit 24 is performed, and the ink 80 remaining on the nozzle surface 245 is sucked (adsorbed) by the cleaning member 70 for cleaning.

[0068] Next, when the ink 80 remaining on the nozzle surface 245 is cleaned, the control unit 40 controls the take-up roller 64 to end the take-up operation of the cleaning member 70 (step S140).

[0069] Next, the control unit 40 controls the press-contact separation unit 246 to move the head unit 24 upward to separate the nozzle surface 245 of the head unit 24 from the cleaning member 70 (step S160).

[0070] Next, the control unit 40 obtains the detection result of the dirt state detection unit 90, specifically, the concentration of the ink 80 as the dirt state of the cleaning member 70 (step S180). Next, the control unit 40 determines whether or not the obtained concentration of the ink 80 is below the threshold value (step S200). As a result of the determination, if the concentration of the ink 80 is not below the threshold value (step S200, NO), since there is no reusable portion for the next cleaning, the inkjet image forming apparatus 1 ends the take-up control operation.

[0071] On the other hand, when the concentration of the ink 80 is below the threshold value (step S200, YES), since there is a reusable portion for the next cleaning, the control unit 40 controls the take-up roller 64 to start the rewinding operation of the cleaning member 70 (step S220). Finally, the control unit 40 controls the take-up roller 64 to end the rewinding operation of the cleaning member 70 at the timing when it is wound up by a distance corresponding to the portion wiped off from the cleaning member 70 (the reusable portion for cleaning) in the winding direction of the cleaning member 70 (step S240). When the process of step S240 is completed, the inkjet image forming apparatus 1 ends the winding control operation.

[0072] As described in detail above, the inkjet image forming apparatus 1 (image forming apparatus) in the present embodiment contacts the nozzle surface 245 of the head unit 24 that forms an image on the recording medium P by the inkjet head 242, and cleans the ink 80 remaining on the nozzle surface 245. It includes a cleaning member 70, a winding unit (take-up roller 64) that winds up the cleaning member 70 so that the cleaning member 70 contacts the nozzle surface 245, a dirt state detection unit 90 that detects the dirt state of the cleaning member 70 after cleaning, and a control unit 40 that controls the winding unit to rewind the cleaning member 70 according to the detected dirt state (concentration of the ink 80). Specifically, in cleaning, when the concentration of the ink 80 as the detected dirt state is below the threshold value, the control unit 40 controls to rewind the cleaning member 70.

[0073] According to the present embodiment configured in this way, when the amount of ink wiped off by the cleaning member 70 is small, that is, when the amount of the cleaning member 70 required for wiping off the ink is small, the wiped portion is rewound and reused for the next cleaning. As a result, it is possible to prevent an excessive amount of the cleaning member 70 from being wound up and used when the amount of ink wiped off by the cleaning member 70 is small, and thus prevent waste from occurring in the cleaning member 70.

[0074] In addition, in the above-described embodiment, the control unit 40 may change a threshold value (refer to step S200 in FIG. 5) used to determine whether to execute the rewinding operation of the cleaning member 70 according to the color of the ink 80 remaining on the nozzle surface 245. For example, when the color of the ink 80 remaining on the nozzle surface 245 is a dark color, since the density of the ink 80 detected by the dirt state detection unit 90 tends to be large relative to the amount of the ink 80, the control unit 40 increases the threshold value used to determine whether to execute the rewinding operation of the cleaning member 70. On the other hand, when the color of the ink 80 remaining on the nozzle surface 245 is a light color, since the density of the ink 80 detected by the dirt state detection unit 90 tends to be small relative to the amount of the ink 80, the control unit 40 increases the threshold value used to determine whether to execute the rewinding operation of the cleaning member 70. From the same viewpoint, the control unit 40 may change the threshold value according to the type of the ink 80 remaining on the nozzle surface 245 (for example, dye ink, pigment ink).

[0075] Also, in the above-described embodiment, the control unit 40 may change the winding speed of the cleaning member 70 in the next cleaning according to the dirt state detected by the dirt state detection unit 90. For example, when the density of the ink 80 as the dirt state detected by the dirt state detection unit 90 is high, since the ink 80 tends to remain on the nozzle surface 245 and it is necessary to increase the cleaning force by the cleaning member 70, the control unit 40 increases the winding speed of the cleaning member 70 in the next cleaning and increases the liquid absorption frequency of the cleaning member 70 regardless of whether the rewinding operation of the cleaning member 70 is performed. Further, the control unit 40 may control the winding roller 64 so as to change the winding speed of the cleaning member 70 in a plurality of stages according to the dirt state (for example, the levels of a plurality of dirt states) detected by the dirt state detection unit 90.

[0076] In the above embodiment, the inkjet image forming apparatus 1 is a single-pass type inkjet image forming apparatus, but the present invention may be applied to an inkjet image forming apparatus that records an image while scanning a head unit. Also, the present invention may be applied to an inkjet image forming apparatus in which a single nozzle is provided in a head unit.

[0077] In addition, the above-mentioned embodiments are merely examples of the embodiment of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these. In other words, the present invention can be embodied in various forms without departing from the gist or main characteristics of the present invention. [Explanation of symbols]

[0078] 1. Inkjet image forming device 2 External device 10 Paper feed section 11 Paper feed tray 12 Media supply section 20 Image forming section 21 Conveyor 211 Transport drum 211a Transport surface 22 Delivery Unit 23 Heating section 24 Head Unit 241 Head drive unit 242 Inkjet head 243 Nozzle 244 Mounting material 245 Nozzle surface 246 Pressure-welded separation part 25 Fixing section 28 Delivery Department 30 Paper output section 31 Output tray 40 Control section 41 CPU 42 RAM 43 ROM 44 Storage section 51 Conveyor drive unit 52 Operation display section 53 Input / Output Interface 55 Cleaning Device 61 Backup Member 62 Feeding Roller 64 Take-up Roller 70 Cleaning Member 80 Ink 90 Contamination State Detection Unit P Recording Medium

Claims

1. A cleaning member that contacts a nozzle surface of a head unit that forms an image on a recording medium by an inkjet head and cleans ink remaining on the nozzle surface; A winding unit that winds the cleaning member so that the cleaning member contacts the nozzle surface; A contamination state detection unit that detects a contamination state of the cleaning member after cleaning; A control unit that controls the winding unit to wind back the cleaning member according to the detected contamination state; A cleaning device comprising the above.

2. The contamination state detection unit optically detects the contamination state of the cleaning member. The cleaning device according to Claim 1.

3. The contamination state detection unit detects the contamination state of the cleaning member by detecting the concentration of ink adhering to the cleaning member. The cleaning device according to Claim 1 or 2.

4. When the detected concentration is equal to or less than a threshold value, the control unit controls the winding unit to wind back the cleaning member. The cleaning device according to Claim 3.

5. The control unit changes the threshold value according to the color of the ink remaining on the nozzle surface. The cleaning device according to Claim 4.

6. The control unit changes the threshold value according to the type of ink remaining on the nozzle surface. The cleaning device according to Claim 4 or 5.

7. The control unit controls the winding unit to change the winding speed of the cleaning member in the next cleaning according to the detected contamination state. The cleaning device according to any one of Claims 1 to 6.

8. The control unit controls the winding unit to change the winding speed of the cleaning member in the next cleaning in a plurality of stages according to the detected contamination state. The cleaning device according to Claim 7.

9. A cleaning device according to any one of Claims 1 to 8; The head unit; An image forming apparatus comprising the above.

10. A cleaning member that contacts a nozzle surface of a head unit that forms an image on a recording medium by an inkjet head and cleans ink remaining on the nozzle surface; A winding control method for a cleaning device including a winding unit that winds the cleaning member so that the cleaning member contacts the nozzle surface, detecting a soiled state of the cleaning member after cleaning, controlling the winding unit to rewind the cleaning member according to the detected soiled state, winding control method.

Images