JP2007076211A - Maintaining-recovering device for head, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that images are disturbed by the adhesion of paper powder to a residual recording liquid on the wiping rear end of a nozzle surface accompanied by the wiping of a recording head, or the inside of the device is soiled. <P>SOLUTION: A maintaining-recovering mechanism 121 is equipped with caps 122a to 122e which cap the nozzle surface 24a of the recording head 24, and a wiper blade 124 which wipes the nozzle surface. The maintaining-recovering mechanism 121 is equipped with a removing member 128. In this case, the removing member 128 is provided in the longitudinal direction of the wiper blade 124, vertically moves to the nozzle surface 24a of the stopped recording head 24, and removes the residual recording liquid remaining on the end section on the downstream side in the wiping direction of the nozzle surface 24a of the recording head 24. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a head maintenance / recovery device and an image forming apparatus.

  2. Related Art As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, and a composite machine of these, for example, an ink jet recording apparatus is known as an image forming apparatus of a liquid discharge recording method using a recording head that discharges a recording liquid droplet. . This ink jet recording apparatus means a recording liquid (for example, ink droplets) conveyed from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). And recording medium or recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). There are a serial type in which the recording head moves in the main scanning direction and a line type using a line type recording head.

  In such an image forming apparatus, an apparatus that maintains and recovers the performance of the recording head that discharges the recording liquid is indispensable. A maintenance / recovery device for maintaining / recovering the performance of the head generally covers the nozzle surface with high airtightness in order to prevent thickening and sticking of the recording liquid in the vicinity of the nozzle due to natural evaporation of ink as recording liquid. A moisturizing cap, a suction cap for sucking and discharging the thickened recording liquid from the nozzle (sometimes also used as a moisturizing cap), and wiping and removing the recording liquid adhering to the nozzle surface Wiper blades (cleaning blades, wipers, blade members, blades are also used in the same meaning), idle discharge receptacles for performing idle discharge for discharging liquid droplets that do not contribute to image formation, and the like.

Regarding a conventional head maintenance / recovery mechanism (device), for example, in Patent Document 1, when wiping to the end of the nozzle surface is performed with a wiper blade, ink is scattered by restoration when the wiper blade leaves the nozzle surface. Therefore, the wiper blade is formed or fixed on a belt that moves along a direction perpendicular to the scanning direction of the carriage, and at least a plurality of wiper blades that are arranged in parallel along the movement direction with an appropriate interval therebetween. A blade group, and at the time of wiping and removing ink, at least one blade other than the frontmost blade in the blade group is disposed at a position in contact with the head so that the frontmost blade A wiping device is described which is adapted to prevent scattering.
JP 2002-283581 A

In Patent Document 2, since ink remains on the side surface of the head when wiping with the wiper blade is repeated, the wiper blade is moved to a position where it can come into contact with the side surface of the head, and then the head is moved to move the side surface. It is described that the ink remaining on the side surface of the head is transferred to the side surface of the wiper blade by contacting the side surface of the wiper blade.
JP 2003-025596 A

In Patent Document 3, when a discharge nozzle having a plurality of nozzles has a shape protruding from the lower surface of the head, unnecessary ink adheres to the protruding side portion, and ink drops and the like are dropped. In view of the above, there is described a side wiper that wipes the side of the discharge nozzle and a tip wiper that wipes the tip of the discharge nozzle.
JP 2001-130013 A

  As described above, when wiping the nozzle surface of the recording head with the wiping member, if the wiping member moves relative to the position away from the nozzle surface while being in contact with the nozzle surface, when the wiping member leaves the nozzle surface, In order to restore the shape, the ink attached to the wiping member and the ink attached to the downstream end of the nozzle surface in the wiping direction may be repelled and scattered. Stop at the side edge and leave it away from the nozzle face.

  Therefore, a part of the ink collected at the wiping end position of the nozzle surface by the wiping member remains at the edge portion (wiping end position) of the nozzle surface. Due to the thickening of the remaining ink, paper dust or the like flying in the apparatus adheres to the residual ink, and the ink further adheres to the paper dust or the like attached by repeating the recovery operation. The recording medium will be soiled.

  In particular, recently, when printing on plain paper, it can be printed satisfying properties such as image color reproducibility, durability, light resistance, ink drying, character bleeding, color boundary bleeding, double-sided printing property, A pigment-based ink composed of a solvent containing a wetting agent (humectant), a penetrating agent and the like in water and a pigment is used as a recording liquid. Such a pigment-based ink has a higher viscosity than a general dye-based ink, and the time until the solvent component evaporates and loses its fluidity is short. Residual ink left unwiped at the end (the end after wiping) cannot be easily removed.

  In this case, the wiping device described in Patent Document 2 described above includes a mechanism for removing the residual ink on the side surface of the head using the back surface of the wiper wiping member, but wiping count and position control are required. Therefore, the operation time is also long. Further, since this is a mechanism for transferring rather than wiping, there is a problem that it is difficult to remove paper dust and the like from the edge portion of the nozzle surface of the recording head. On the other hand, since the wiping operation interval changes depending on the frequency of use by the user, there is a problem in that the residual ink adhesion state also changes and a normal wiping operation cannot be performed.

  Moreover, since the thing of patent document 3 has many components and implements the wiping direction along the longitudinal direction of a recording head, there exists a subject that operation time takes.

  The present invention has been made in view of the above problems, and maintains the head that can remove the remaining recording liquid remaining on the trailing edge of the head with a simple configuration without extending the time required for the recovery operation. It is an object of the present invention to provide a recovery device and an image forming apparatus including the maintenance / recovery device.

  In order to solve the above-described problems, a head maintenance / recovery device according to the present invention is provided along the longitudinal direction of the wiping member, and moves up and down with respect to the nozzle surface of the stopped recording head. A removing member for removing residual recording liquid remaining at the downstream end portion in the wiping direction is provided.

  Here, it is preferable that the removing member hits the downstream end of the nozzle surface of the recording head in the wiping direction to transfer and remove the residual recording liquid. Further, it is preferable that the removing member slides in contact with the downstream end portion of the nozzle surface of the recording head in the wiping direction, wipes away the remaining recording liquid, and moves to the head side surface side.

  The removing member is preferably an elastic member, and in this case, the removing member is preferably mylar. Moreover, it is preferable that the surface of the front-end | tip part of a removal member is given the texturing process. Moreover, it is preferable that the front-end | tip part surface of the removal member is hydrophilically processed. Further, the water repellency of the surface of the removing member is preferably lower than the water repellency of the nozzle surface of the recording head.

  Furthermore, it is preferable that the removing member moves up and down in conjunction with the up and down movement of the cap member. The removing member is preferably provided on a suction cap member or a holding member that holds the suction cap member. Moreover, it is preferable that the removal member is provided in the holding member holding the cap member for moisturizing or the cap member for moisturizing. In this case, the removing member can be fixed to the holding member holding the cap member with an adhesive, or can be fixed to the holding member with a pressing member. Alternatively, the removal member can be integrally formed with the cap member.

  The image forming apparatus according to the present invention includes the head maintenance / recovery device according to the present invention.

  Here, the recording head is preferably provided with a nozzle cover that covers the periphery of the nozzle surface, and the surface of the nozzle cover is preferably subjected to water repellent treatment. Further, it is preferable to perform an operation of removing the remaining recording liquid at the downstream end portion in the wiping direction after wiping the nozzle surface of the recording head. Further, it is preferable to perform an operation of removing the residual recording liquid at the downstream end in the wiping direction after wiping the nozzle surface of the recording head twice. Further, the viscosity of the recording liquid is preferably 5 (mPa · s) or more. The recording liquid is preferably a pigment-based ink containing a pigment in the color material.

  According to the head maintenance and recovery mechanism and the image forming apparatus according to the present invention, the wiping direction of the nozzle surface of the recording head is provided along the longitudinal direction of the wiping member and moves up and down with respect to the nozzle surface of the stopped recording head. Since the removal member for removing the remaining recording liquid remaining at the downstream end is provided, the remaining recording liquid remaining at the wiping end of the head can be simply configured to extend the time required for the recovery operation. Can be removed. Thereby, it is possible to prevent contamination in the apparatus and deterioration of image quality.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. An example of an image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram showing the overall configuration of the image forming apparatus, and FIG. 2 is an explanatory plan view of an image forming unit and a sub-scanning conveying unit of the apparatus.

  This image forming apparatus has an image forming part (means) 2 for forming an image, a sub-scanning conveying part (means) 3, etc. in the inside (enclosure) of the apparatus main body 1. A recording medium (hereinafter referred to as “paper”, but the material is not limited to paper) 5 serving as a transported member is separated and fed one by one from a paper feeding unit (means) 4 serving as a housing unit. Paper is formed and the sub-scanning conveyance unit 3 intermittently conveys the paper 5 at a position facing the image forming unit 2 while the image forming unit 2 ejects droplets onto the paper 5 to form (record) a desired image. After that, the paper 5 is discharged onto a paper discharge tray 7 formed on the upper surface of the apparatus main body 1 through the paper discharge conveyance unit 6. The image forming unit 2 and the sub-scanning conveyance unit 3 are unitized to form an engine unit 100 that is detachably attached to the apparatus main body 1.

  The image forming apparatus also has an image reading unit (scanner) for reading an image above the discharge tray 7 above the apparatus main body 1 as an input system for image data (print data) formed by the image forming unit 2. Part) 11. The image reading unit 11 includes a scanning optical system 15 including an illumination light source 13 and a mirror 14 and a scanning optical system 18 including mirrors 16 and 17. The scanned document image is read as an image signal by the image reading element 20 disposed behind the lens 19, and the read image signal is digitized and subjected to image processing, and the image-processed print data is printed. be able to. A pressure plate 10 is provided on the contact glass 12 for pressing the document.

  Here, as shown in FIG. 2, the image forming unit 2 of the image forming apparatus holds the carriage 23 movably in the main scanning direction by a carriage guide 21 and a guide stay (not shown), and is driven by a main scanning motor 27. It moves and scans in the main scanning direction via a timing belt 29 spanned between the pulley 28A and the driven pulley 28B.

  On the carriage 23, as shown in FIGS. 3 and 4, recording heads 24k1 and 24k2 each composed of two droplet discharge heads for discharging black (Bk) ink, and cyan (C) ink, respectively. , Recording heads 24c, 24m, and 24y each including one droplet discharge head that discharges magenta (M) ink and yellow (Y) ink (when the colors are not distinguished and collectively referred to as “recording head 24”). ) A total of five droplet discharge heads are mounted, the carriage 23 is moved in the main scanning direction, and the sub-scan transport unit 3 feeds the paper 5 in the paper transport direction (sub-scanning direction) while the droplets from the recording head 24. Is a shuttle type in which image formation is performed by discharging the liquid.

  The nozzle surface 24a of the recording head 24 is configured by covering the periphery of a nozzle plate 24N, in which two nozzle rows composed of a plurality of nozzles 24n for discharging recording droplets are formed, with a nozzle cover 24b. The surface of the nozzle plate 24N and the surface of the nozzle cover 24b are subjected to water repellent treatment.

  In addition, a sub tank 25 is mounted on the carriage 23 in order to supply a recording liquid of a required color to each recording head 24. On the other hand, as shown in FIG. 1, recording liquid containing black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink from the front of the apparatus main body 1 to the cartridge mounting portion 26A. Each color ink cartridge 26 can be detachably mounted, and ink (recording liquid) is supplied from each color ink cartridge 26 to each color sub-tank 25 via a tube (not shown). The black ink is supplied from one ink cartridge 26 to the two sub tanks 25.

  The recording head 24 uses a piezoelectric element as a pressure generating means (actuator means) for pressurizing the ink in the ink flow path (pressure generation chamber) to deform the vibration plate that forms the wall surface of the ink flow path. A so-called piezo type that discharges ink droplets by changing the volume in the flow channel, or discharges ink droplets with a pressure generated by heating the ink in the ink flow channel using a heating resistor to generate bubbles. The so-called thermal type, the diaphragm that forms the wall surface of the ink flow path and the electrode are placed opposite to each other, and the diaphragm is deformed by the electrostatic force generated between the vibration plate and the electrode, thereby the ink flow path inner volume It is possible to use an electrostatic type or the like that discharges ink droplets by changing the above.

  Further, a head maintenance / recovery mechanism (device) 121 according to the present invention for maintaining and recovering the state of the nozzles of the recording head 24 is disposed in a non-printing area on one side of the carriage 23 in the scanning direction. The maintenance / recovery mechanism 121 is a cap member for capping each nozzle surface 24a of the five recording heads 24, and includes one suction cap 122a that also serves as a moisture retention, and four moisture retention caps 122b to 122e. A wiper blade 124, which is a wiping member for wiping the nozzle surface 24a of the recording head 24, an idle discharge receiver 125 for performing idle discharge, and a removal member 128 according to the present invention are disposed.

  Further, an idle ejection receptacle 126 for performing idle ejection is disposed in the non-printing area on the other side of the carriage 23 in the scanning direction. Openings 127 a to 127 e are formed in the idle discharge receptacle 126.

  The sub-scanning conveyance unit 3 includes a conveyance roller 32 and a tension roller that are driving rollers for conveying the paper 5 fed from below by facing the image forming unit 2 by changing the conveyance direction by approximately 90 degrees. An endless conveyance belt 31 that is stretched between the driven rollers 33, a charging roller 34 that is a charging unit to which an AC bias voltage that is an alternating voltage is applied to charge the surface of the conveyance belt 31, and a conveyance belt 31 The image is formed by the guide member 35 that guides the sheet 5 in the opposite region of the image forming unit 2, the pressing roller 36 that presses the paper 5 against the conveying belt 31 at the position facing the conveying roller 32, and the image forming unit 2. A separation claw 37 for separating the formed paper 5 from the transport belt 31 and a transport roller 38 for feeding the separated paper 5 to the paper discharge transport unit 6 are provided.

  The transport belt 31 of the sub-scan transport unit 3 is rotated in the paper transport direction (sub-scan direction) in FIG. 2 by rotating the transport roller 32 from the sub-scan motor 131 through the timing belt 132 and the timing roller 133. It is configured to do.

  The paper feeding unit 4 is detachable from the apparatus main body 1 and separates the paper 5 in the paper feeding cassette 41 one by one from the paper feeding cassette 41 which is a storing means for stacking and storing a large number of papers 5. A sheet feeding roller 42 and a friction pad 43 for feeding out, and a registration roller pair 44 for conveying the fed sheet 5 to the sub-scanning conveying unit 3 are provided. The sheet feeding roller 42 is rotated by a sheet feeding motor (drive source) 45 including an HB type stepping motor via a sheet feeding clutch (not shown), and the registration roller pair 44 is also rotated by the sheet feeding motor 45.

  The paper discharge conveyance unit 6 includes a pair of paper discharge conveyance rollers 61 and 62 for conveying the paper 5 on which image formation has been performed, a paper discharge conveyance roller pair 63 and a paper discharge roller 64 for sending the paper 5 to the paper discharge tray 7. And.

  In the image forming apparatus configured as described above, the rotation amount of the conveyance roller 32 that drives the conveyance belt 31 is detected, and the sub-scanning motor 131 is driven and controlled according to the detected rotation amount, and an AC (not shown) is also illustrated. A positive and negative rectangular wave high voltage, which is an alternating voltage, is applied from the bias supply unit to the charging roller 34, whereby positive and negative charges are alternately band-shaped in the conveying direction of the conveying belt 31. And is charged with a predetermined charging width on the conveying belt 31 to generate an unequal electric field.

  Therefore, the conveyance belt in which an unequal electric field is generated by the sheet 5 being fed from the sheet feeding unit 4 and fed between the conveyance roller 32 and the pressing roller 36 to form positive and negative charges. When fed onto the paper 31, the paper 5 is instantly polarized according to the direction of the electric field, and is attracted onto the transport belt 31 by the electrostatic attraction force, and is transported as the transport belt 31 moves.

  Then, while the paper 5 is intermittently transported by the transport belt 31, recording liquid droplets are ejected from the recording head 24 onto the paper 5 to record (print) an image, and the front end of the paper 5 on which printing is performed The side is separated from the conveyance belt 31 by the separation claw 37 and sent to the paper discharge conveyance unit 6 by the conveyance roller 38.

  Further, during printing (recording) standby, the carriage 23 is moved to the maintenance / recovery mechanism 121 side, and the nozzle surface of the recording head 34 is capped by the cap 122 so that the nozzles are kept in a wet state. To prevent. In addition, the recording liquid is sucked from the nozzle in a state where the recording head 34 is capped by the suction and moisturizing cap 122a (referred to as “nozzle suction” or “head suction”), and the recovered recording liquid and bubbles are discharged. In order to clean and remove ink adhering to the nozzle surface of the recording head 34 by this recovery operation, the wiper blade 124 performs wiping. In addition, a blank ejection operation is performed in which ink that is not related to printing is ejected toward the blank ejection receiver 125 before recording is started or during recording. As a result, the stable ejection performance of the recording head 34 is maintained.

Here, the head maintenance / recovery mechanism (device) 121 will be described with reference to FIGS. 5 is a schematic explanatory view of the maintenance mechanism, FIG. 6 is a specific perspective explanatory view of the maintenance mechanism, and FIG. 7 is a side explanatory view of the same.
As described above, the maintenance and recovery mechanism 121 includes a cap holder 421A, which is a holding member including a holding mechanism for holding the moisturizing and sucking cap (hereinafter referred to as “suction cap”) 122a and the moisturizing cap 122b; A cap holder 421B including a holding mechanism for holding the moisturizing caps 122c to 122e; a wiper blade 124 which is a blade made of an elastic body as a cleaning means for cleaning (wiping) the nozzle surface of the recording head 24; An empty discharge receiver 125 for performing an empty discharge operation for discharging droplets that do not contribute to printing from the recording head 24, a removing member 128 according to the present invention attached to the cap holder 421A, and a wiper blade 124 are connected to the empty discharge receiver 125. The recording liquid adhering to the wiper blade 128 when pressed to the side. Wiper pressing member 129 for cleaning by scraped off only 125 side is disposed.

  A tubing pump (suction pump) 423, which is a suction means, is connected to the moisturizing and suction cap 122a via a flexible tube 422. Therefore, when performing the maintenance recovery operation of the recording head 24, the recording head 24 performing the recovery operation is selectively moved to a position where it can be capped by the suction cap 122a.

  A cam shaft 412 rotatably supported by the frame 411 is disposed below the cap holders 421A and 421B, and a cap for moving the cap holders 421A and 421B up and down (up and down movement) is provided on the cam shaft 412. Cams 413A and 413B and a wiper cam 414 for raising and lowering the wiper blade 124 are provided. Although the cam positions at which the caps 122a to 122e reach the top dead center are not the same, for the convenience of illustration, the caps 122a to 122e and the cams 413A to 413C are shown at the same height. Further, although a cam for swinging the wiper cleaner 129 is also provided, the illustration is omitted.

  Further, a carriage lock 415 that engages with the carriage 23 and locks the movement of the carriage 23 is provided. The carriage lock 415 is urged upward (in the lock direction) by a compression spring (not shown), and is provided on the cam shaft 412. The carriage is moved up and down via a carriage lock arm 417 driven by a lock cam 416.

  In order to rotationally drive the tubing pump 423 and the camshaft 412, the rotation of the motor 431 is meshed with the motor gear 432 provided on the motor shaft 431 a and the pump gear 433 provided on the pump shaft 423 a of the tubing pump 423 is meshed. An intermediate gear 434 with a one-way clutch 437 is engaged with an intermediate gear 434 integrated with 433 via an intermediate gear 435, and the intermediate gear 438 coaxial with the intermediate gear 436 is fixed to the camshaft 412 via the intermediate gear 439. The cam gear 440 is engaged.

  In the head maintenance mechanism 121, when the motor 431 rotates in the forward direction, the motor gear 432, the intermediate gear 433, the pump gear 434, the intermediate gears 435 and 436 rotate, and the shaft 423a of the tubing pump 423 rotates, whereby the tubing pump 423 is rotated. Operates to suck the inside of the suction cap 122a. Since the other gears 438 and thereafter are blocked by the one-way clutch 437, they do not rotate (activate).

  Further, since the one-way clutch 437 is connected by the reverse rotation of the motor 431, the rotation of the motor 431 is transferred to the cam gear 440 via the motor gear 432, the intermediate gear 433, the pump gear 434, the intermediate gears 435, 436, 438, and 439. As a result, the cam shaft 412 rotates. At this time, the tubing pump 423 has a structure that does not rotate by the reverse rotation of the pump shaft 423a.

  Here, the removal member 128 is provided along the longitudinal direction of the wiper blade 124, and moves up and down with respect to the nozzle surface 24a of the stopped recording head 24, and the downstream end of the nozzle surface 24a of the recording head 24 in the wiping direction. The residual recording liquid remaining on the substrate is removed.

  Since the removal member 128 is moved up and down in conjunction with the vertical movement of the cap member, as shown in a simplified manner in FIG. 8A, the removal member 128 is held via an elastic member 420 that urges the suction cap 122a upward. It is fixed to the cap holder 421, which is a holding member, with an adhesive 220. In this case, by using an epoxy adhesive as the adhesive, ink resistance can be ensured even when ink adheres to the removal member 128.

  Further, as shown in FIG. 8B, instead of adhesive bonding, the removal member 128 can be fixed by a pressing member 221 that presses the removal member 128. In this way, the removal member 128 can be easily replaced. become. As the pressing member 221, not only a member that presses and fixes the removing member 128 but also a member in which a slit into which the lower end portion of the removing member 128 is inserted (which may be integrally formed with the cap holder) can be used. .

  Further, the removing member 128 is formed of an elastic member. Since the removing member 128 has elasticity, it is possible to prevent the recording head 24 from being damaged when the recording head 24 is not waiting at the correct position during the removing operation.

  In this embodiment, the removal member 128 is made of Mylar made of PET, so that the cost is reduced, the elasticity is provided, and the wettability of the removal member 128 is made larger than the nozzle surface 24a of the recording head 24. Thus, the residual recording liquid on the nozzle surface 24 a of the recording head 24 can be transferred (transferred) to the removing member 128. Further, the distal end portion 128a of the removing member 128 is inclined obliquely in the wiping direction.

Next, an outline of the control unit of the image forming apparatus will be described with reference to the block diagram of FIG.
The control unit 300 retains data even when the power of the apparatus is shut off, the CPU 301, the ROM 302 that stores programs executed by the CPU 301 and other fixed data, the RAM 303 that temporarily stores image data and the like. Control of the entire apparatus, including a non-volatile memory (NVRAM) 304 and an ASIC 305 that processes input / output signals for performing various signal processing and rearrangement on image data and other input / output signals for controlling the entire apparatus. A main control unit 310 is provided.

  The control unit 300 is interposed between the host side and the main control unit 310, and includes an external I / F 311 for transmitting and receiving data and signals, and a head driver for driving and controlling the recording head 24. The sub-scanning motor 131 is driven based on the print control unit 312 including the main scanning driving unit (motor driver) 313 for driving the main scanning motor 27 that moves and scans the carriage 23, and the detection result of the rotary encoder 138. A sub-scanning drive unit 314 for driving the paper feed motor 49, a paper feed drive unit 315 for driving the paper feed motor 49, and a paper discharge drive unit 316 for driving a paper discharge motor 79 that drives each roller of the paper discharge transport unit 6. A recovery system drive unit 318 for driving the maintenance / recovery motor 431 that drives the maintenance / recovery mechanism 121, and an AC bias supply for supplying an AC bias to the charging belt 34 And a 319.

  Further, the control unit 300 includes a solenoid driving unit (driver) 322 that drives various solenoids (SOL) 321, a clutch driving unit 324 that drives an electromagnetic crack 323 related to paper feed, and the image reading unit 11. A scanner control unit 325 for controlling.

  Further, the main control unit 310 receives various detection signals from various sensors 326 for detecting paper, and includes various keys such as a numeric keypad and a print start key provided on the apparatus main body 1 and various operations / displays including various indicators. Necessary key input with the display unit 327 is taken in and display information is output.

Next, an example of ink that is a recording liquid used in the image forming apparatus will be described.
The ink is a pigment-based aqueous ink having a high viscosity by increasing the components of the colorant. This water-based ink is obtained by dispersing a colorant in an aqueous dispersion mainly composed of water. This water-based ink has an ink surface tension of 35 [mN / cm] or less and an ink viscosity of 5 [mPa · sec] at 25 ° C. or more. By setting the ink surface tension of the ink liquid to 35 [mN / cm] or less, the penetration speed into the paper can be increased. Further, by setting the ink viscosity at 25 ° C. to 5 [mPa · sec] or more, it is possible to obtain an ink having excellent quick drying properties. In addition, since it is difficult to blur, a sharp image can be obtained.

  As the colorant, hydrophobic dyes and pigments can be used, and organic pigments and carbon black are particularly preferable.

  The aqueous dispersion is preferably an aqueous dispersion of polymer fine particles, and examples of the polymer used include a vinyl polymer, a polyester polymer, and a polyurethane polymer. Among the polymers, vinyl polymers are preferable.

  Further, the ink has a wetting agent added so as to have a surface tension of 35 [mN / cm] or less. Examples of the wetting agent include glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylolethane. At least one kind can be used.

  Furthermore, a polyol or glycol ether having 8 to 11 carbon atoms, an anionic or nonionic surfactant is added.

Examples thereof include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and substances having the following structures (I) to (VII).

（Ｒ１：炭素数６〜１４の分岐してもよいアルキル基、ｍ：３〜１２、 Ｍ：アルカリ
金属イオン、第４級アンモニウム、第４級ホスホニウム、アルカノールアミン）

(R1: alkyl group having 6 to 14 carbon atoms which may be branched, m: 3 to 12, M: alkali metal ion, quaternary ammonium, quaternary phosphonium, alkanolamine)

（Ｒ２：炭素数５〜１６の分岐したアルキル基、Ｍ：アルカリ金属イオン、第４級アン
モニウム、第４級ホスホニウム、アルカノールアミン）

(R2: branched alkyl group having 5 to 16 carbon atoms, M: alkali metal ion, quaternary ammonium, quaternary phosphonium, alkanolamine)

（Ｒは分岐しても良い６〜１４の炭素鎖、ｋ：５〜２０）

(R may be branched 6-14 carbon chain, k: 5-20)

（Ｒは分岐しても良い炭素数６から１４の炭素鎖、ｎ：５〜２０）

(R is a carbon chain having 6 to 14 carbon atoms which may be branched, n: 5 to 20)

（Ｒは炭素数６から１４の炭素鎖、ｍ，ｎ：ｍ、ｎ≦２０）

(R is a carbon chain having 6 to 14 carbon atoms, m, n: m, n ≦ 20)

（Ｒは炭素数６から１４の炭素鎖、ｍ，ｎ：ｍ、ｎ≦２０）

(R is a carbon chain having 6 to 14 carbon atoms, m, n: m, n ≦ 20)

（ｐ、ｑは０〜４０）

(P and q are 0 to 40)

  As a method for obtaining the ink, a polymer is dissolved in an organic solvent, and a pigment, water, a wetting agent, a surfactant and the like are added and kneaded to obtain a paste. The paste is diluted with water as necessary, and an organic solvent is obtained. A method of distilling off the solvent to form an aqueous system is preferred.

Examples of the ink liquid will be described below, but are not limited thereto.
[Cyan ink]
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of lithium hydroxide so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and obtained the ink composition.
Phthalocyanine pigment-containing polymer fine particles 10.0 wt% (as solids)
1,3-butanediol 25.0 wt%
Glycerol 8.5wt%
_{CH 3 (CH 2) 12 O} (CH 2 CH 2 O) 3 CH 2 COOH
Active agent 2.0wt%
2-ethyl-1,3-hexanediol 1.8wt%
Proxel LV (preservative) 0.1wt%
Defoamer 0.05wt%
Residual amount of ion-exchanged water Thus, a C-color water-based ink liquid was obtained as a polymer fine particle water dispersion containing a dimethylquinacridone pigment.

[Magenta ink]
An ink composition was prepared in the same manner as the cyan ink except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Dimethylquinacridone pigment-containing polymer fine particles 0.5wt% (as solids)
1,3-butanediol 22.0 wt%
Glycerol 7.0wt%
Polyoxyalkylene derivative Dispanol TOC 2.0wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.05wt%
Defoamer 0.1wt%
Residual amount of ion-exchanged water As a result, an M-color aqueous ink liquid was obtained as an aqueous dispersion of polymer fine particles containing a dimethylquinacridone pigment.

[Yellow ink]
An ink composition was prepared in the same manner as the cyan ink except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
Monoazo yellow pigment-containing polymer fine particles 10.0wt% (as solids)
1,3-butanediol 23.5 wt%
Glycerol 7.5wt%
Polyoxyalkylene derivative Dispanol TOC 2.0wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.05wt%
Antifoam KM72F 0.1wt%
Residual amount of ion-exchanged water As a result, a Y-color aqueous ink liquid was obtained as an aqueous dispersion of polymer fine particles containing a monoazo yellow pigment.

[Black ink]
An ink composition was prepared in the same manner as the cyan ink except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Carbon black dispersion treated with diazo compound 10.0wt%
1,3-butanediol 22.5 wt%
Glycerol 7.5wt%
N-methyl-2-pyrrolidone 2.0wt%
_{CH 3 (CH 2) 12 O} (CH 2 CH 2 O) 3 CH 2 COOH
Active agent 2.0wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Defoamer 0.1wt%
Residual amount of ion-exchanged water Thereby, a Bk color water-based ink liquid was obtained as a polymer fine particle water dispersion containing carbon black.

  The physical properties of these inks are as shown in Table 1.

  When an image was formed on plain paper using the ink having the above physical properties, a good image could be obtained without blurring of characters and color boundaries. In particular, the complex kanji, slanted lines and curved lines were recorded smoothly and naturally. Moreover, even if it was allowed to stand for 2 to 3 days, there was no nozzle clogging despite the high viscosity, and stable printing performance was obtained.

Next, the maintenance / recovery operation in this image forming apparatus will be described with reference to FIG.
First, generation of residual recording liquid accompanying wiping by wiping of the nozzle surface 24a of the recording head 24 will be described with reference to FIG. 10. When the wiper blade 124 is raised as shown in FIG. 23, the recording head 24 is relatively moved by moving and scanning, and the wiper blade 124 is moved in the wiping direction with the wiper blade 124 in contact with the nozzle surface 24a of the recording head 24 as shown in FIG. The ink is moved to the end of 24a, and the ink adhering to the nozzle surface 24a of the recording head 24 is wiped off.

  The relative movement of the wiper blade 124 is stopped at a position immediately before the wiper blade 124 is separated from the downstream end 24ae of the nozzle surface 24a in the wiping direction, and the wiper blade 124 is lowered as shown in FIG. As a result, the wiper blade 124 does not pass through the nozzle surface 24a (the nozzle surface 24a is not wiped off) while the tip is curved, so that the ink transferred to the tip of the wiper blade 124 is not scattered.

  However, as a result, an unblowed portion is generated at the downstream end 24ae of the nozzle surface 24a of the recording head 24 in the wiping direction, and the recording liquid remains attached (residual recording liquid DI is generated). is there. When wiping is repeated, the residual recording liquid DI grows to a negligible level, and becomes dusty when paper dust or the like adheres to it, and the image may be disturbed by rubbing the paper surface to which the droplets have adhered during image formation. .

Next, the operation of removing the residual recording liquid from the recording head by the removing member 128 will be described with reference to FIG. In FIG. 11, the illustration is simplified and one cap member is held by one cap holder.
As shown in FIG. 11A, the carriage 23 is stopped corresponding to the suction cap 122a, and the recording head 24 is stopped. By raising the cap holder 421A in the arrow D direction from this state, the removal member 128 is raised (moved upward) in conjunction with the upward movement of the cap 122a.

  As the removal member 128 moves up in this way, the tip end portion 128a of the removal member 128 adheres to the downstream end 24ae in the wiping direction of the nozzle surface 24a of the recording head 24 as shown in FIG. Since the wettability of the removing member 128 is larger than the nozzle surface 24a of the recording head 24 as described above, the residual recording liquid DI on the nozzle surface 24a of the recording head 24 is on the removing member 128 side. Is transcribed.

  Then, as the removal member 128 is further raised, most of the residual recording liquid DI is transferred to the removal member 128 and the residual recording liquid at the downstream end 24ae in the wiping direction of the nozzle surface 24a as shown in FIG. DI is removed.

  In this way, the residual recording liquid that is provided along the longitudinal direction of the wiping member and moves up and down with respect to the nozzle surface of the stopped recording head to remove the residual recording liquid remaining at the downstream end of the nozzle surface of the recording head in the wiping direction is removed. By providing the removal member, it is possible to remove the residual recording liquid remaining on the trailing edge of the head by the operation of fixing the head and raising the removal member, and paper dust adheres to the residual recording liquid, resulting in a beard shape. It is possible to prevent deterioration in image quality such as disturbing the image and to prevent the inside of the apparatus from being soiled.

Next, an example of the maintenance / recovery operation in this image forming apparatus will be described with reference to the flowchart of FIG. 12 and the schematic explanatory diagram of FIG.
In this maintenance and recovery operation, first, the recording head 24 that performs the recovery operation is set to a position corresponding to the suction cap 122a, the suction cap 122a is raised, the nozzle surface 24a of the recording head 24 is capped, and the suction pump 431 is driven. Then, the suction cap 122a is lowered after nozzle suction for sucking ink from the nozzle 24n of the recording head 24 is performed by setting the inside of the cap 122a to a negative pressure (FIG. 13A).

  Next, the wiper blade 124 is raised, the carriage 23 is moved and scanned to relatively move the wiper blade 124, and the nozzle surface 24a of the recording head 24 that has performed the nozzle suction is wiped (wiping and cleaning), and then the wiper blade 124 is moved. It is lowered (FIG. 13 (b)).

  Thereafter, the suction cap 122a is again raised and brought into contact with the nozzle surface 24a of the recording head 24, whereby the ink remaining on the nozzle surface 24a of the recording head 24 after wiping is transferred to the suction cap 122a. That is, in the case of high-viscosity ink, wiping may not be completely wiped off, so that the ink is transferred to the cap 122a and removed by bringing the cap 122a into contact with the ink remaining after wiping.

  At this time, the removal member 128 also rises in conjunction with the suction cap 122a, and as described above, the ink remaining at the downstream end of the nozzle surface 24a of the recording head 24 in the wiping direction is also transferred to the removal member 128. And removed (FIG. 13C).

  Further, the wiper blade 124 is raised, the carriage 23 is moved and scanned to relatively move the wiper blade 124, and after the second wiping of the nozzle surface 24a of the recording head 24, the wiper blade 124 is lowered (FIG. 13). (D)).

  Thereafter, with the carriage 23 (recording head 24) fixed at that position, the cap holders 421A and 421B are raised to raise the removal member 128, and again at the downstream end of the nozzle surface 24a of the recording head 24 in the wiping direction. The remaining ink is scraped off by transferring it to the removing member 128 (FIG. 13E), and then the other recording heads 24 are similarly operated to maintain and recover all the recording heads 24. Can be performed.

  In this way, the residual recording liquid is removed by the removing member for each of the two wiping operations, so that the residual recording remaining at the downstream end of the wiping direction of the nozzle surface of the recording head accompanying the wiping more reliably. The liquid can be removed.

Here, a configuration for improving transferability of the residual recording liquid to the removing member 128 will be described.
First, the water repellent treatment is preferably performed on the nozzle surface 24a (the surface of the nozzle plate 24N and the surface of the nozzle cover 24b) of the recording head 24. In this case, by making the water repellency of the surface of the removal member 128 lower than the water repellency of the nozzle surface 24 a, the residual recording liquid on the nozzle surface 24 a is easily transferred to the surface of the removal member 128.

  The formation of the water repellent film may be performed under vacuum deposition or may be applied after being dissolved in an appropriate solvent. Speaking of the former, for example, after evacuating the inside of the vacuum chamber to a predetermined degree of vacuum with a vacuum exhaust pump, the water repellent material is vaporized at 400 ° C. and introduced into the vacuum chamber, the vacuum atmosphere is adjusted, and the high frequency power supply The discharge electrode is supplied with electric power to cause RF glow discharge, and the orifice surface of the liquid discharge head is surface-treated in a plasma atmosphere to form the water-repellent film on the orifice surface. Depending on the material and the degree of vacuum in the vacuum chamber, it is possible to form a water-repellent film at a low temperature of about room temperature to about 200 ° C.

  Regarding the latter, for example, a water-repellent material can be dissolved in an organic solvent and coated with a jig such as a wire bar or a doctor blade, or can be spin-coated with a spin coater, or coated with a spray. It can also be dip coated (dipped) in a container filled with a coating solution.

As the water repellent material, an organic compound having a fluorine atom, particularly an organic substance having a fluoroalkyl group, an organic silicon compound having a dimethylsiloxane skeleton, and the like can be used.
As the organic compound having a fluorine atom, fluoroalkylsilane, alkane having a fluoroalkyl group, cambonic acid, alcohol, amine and the like are desirable. Specifically, the fluoroalkylsilane includes heptadecafluoro-1,1,2,2-tetrahydrodecyltrimethoxysilane, heptadecafluoro-1,1,2,2-tetrahydrotrichlorosilane; fluoroalkyl As the alkane having a group, octafluorocyclobutane, perfluoromethylcyclohexane, perfluoro-n-hexane, perfluoro-n-heptane, tetradecafluoro-2-methylpentane, perfluorododecane, perfluoroeucosan; carboxylic acid having a fluorooalkyl group Perfluorodecanoic acid, perfluorooctanoic acid; alcohols having a fluoroalkyl group include 3, 3, 4, 4, 5, 5, 5-heptafluoro-2-pentanol; The emissions, heptadecafluoro over 1,1,2,2-tetrahydro-decyl amine. Examples of organosilicon compounds having a dimethylsiloxane skeleton include α, w-bis (3-aminopropyl) polydimethylsiloxane, α, w-bis (3-glycidoxypropyl) polydimethylsiloxane, α, w-bis (vinyl) poly. Examples thereof include dimethylsiloxane.

As another water-repellent material, an organic compound having a silicon atom or an organic compound having an alkylsiloxane group can be used.
Examples of the organic compound having an alkylsiloxane group include alkylsiloxane groups having two or more alkylsiloxane groups and cycloaliphatic epoxy groups in the molecule constituting the alkylsiloxane epoxy resin composition. The polymer compound (A) containing the structural unit represented by general formula (a) and (b) is mentioned.

  The compound having the above structure also functions as a binder when used in combination with other water-repellent compounds. That is, it improves the workability of the ink-repellent composition and improves the workability as a dry coating film that improves the drying property after evaporation of the solvent.

  The film thickness of the water repellent film is preferably 5 μm or less, more preferably 2 μm or less. When the film thickness exceeds 5 μm, drying of the coating film may be delayed, productivity may be deteriorated, and mechanical durability may be impaired, and peeling may occur when wiping is performed.

  Further, as shown in FIG. 14, the surface of the front end portion 128a of the removal member 128 is subjected to a texture process to form minute irregularities 128b, so that the residual recording liquid on the recording head 24 side is also moved to the removal member 128 side. It becomes easy to transfer (transfer).

Next, a head maintenance / recovery mechanism according to a second embodiment of the present invention will be described with reference to FIG. FIG. 15 is a schematic explanatory diagram of the embodiment.
In this embodiment, the four recording heads 24 that eject K, C, Y, and M recording droplets are each provided with a suction cap 122a and moisture retention caps 122b to 122d that also serve as moisture retention. , Removal members 128A to 12D are provided corresponding to the caps 122a to 122d, respectively.

  With this configuration, for example, when the nozzle suction and wiping are performed on the recording head 24 corresponding to the moisturizing caps 122b to 122d, compared to the case where only the removal member 128A corresponding to the suction cap 122a is provided. Since the recording head 24 can be moved to the position of the moisturizing caps 122b to 128e corresponding to the recording head 24 and the removal member 128 is raised as described above, the residual recording liquid can be removed. The burden on the removal member 128A corresponding to the cap 122a can be reduced, and the removal can be performed over a long period of time.

Next, a head maintenance / recovery mechanism according to a third embodiment of the present invention will be described with reference to FIG. FIG. 16 is a schematic explanatory view including the removal operation process of the embodiment.
In this embodiment, a removal member 228 that moves up and down with respect to the recording head 24 and contacts the wiping end of the nozzle surface 24a of the recording head 24 to transfer the remaining recording liquid is provided. An absorption member 229 that absorbs the recording liquid is provided at the tip of the removal member 228.

  In this embodiment, the removal member 228 is raised with the recording head 24 stopped as shown in FIG. 16A, and the leading end of the removal member 228 is moved to the recording head 24 as shown in FIG. The remaining recording liquid DI remaining at the wiping end is absorbed and transferred to the absorbing member 229 at the front end of the removing member 228, and then contacted with the wiping end of the nozzle surface 24a. As shown in FIG. 4, the removing member 228 is lowered to remove the residual recording liquid.

Next, a head maintenance / recovery mechanism according to a fourth embodiment of the invention will be described with reference to FIG. FIG. 17 is a schematic explanatory view including the removal operation process of the embodiment.
In this embodiment, the removal member 328 moves up and down with respect to the recording head 24 and contacts and slides against the wiping end of the nozzle surface 24a of the recording head 24 to move the residual recording liquid to the side of the head and scrape it off. It has.

  In this embodiment, the removal member 328 is raised while the recording head 24 is stopped as shown in FIG. 17A, and the leading end of the removal member 328 is moved to the recording head 24 as shown in FIG. When the removal member 328 is moved toward the nozzle surface 24a from this state, the tip of the removal member 328 is obliquely upward while being in sliding contact with the nozzle surface 24a as shown in FIG. The residual recording liquid DI remaining at the end of the wiping after the tip of the removing member 328 is scraped off and removed. Unlike the first embodiment, it is scraped off by being moved to the side surface of the head without being transferred to the removing member 328.

Next, a head maintenance / recovery mechanism according to a fifth embodiment of the invention will be described with reference to FIG. FIG. 18 is a schematic explanatory view including the removal operation process of the embodiment.
In this embodiment, a removal member 428 that moves up and down with respect to the recording head 24 and strikes the wiping end of the nozzle surface 24a of the recording head 24 obliquely to scrape the remaining recording liquid is provided. The removal member 428 is formed of an elastic member.

  In this embodiment, the removal member 228 is raised in a state where the recording head 24 is stopped as shown in FIG. 18A, so that the tip of the removal member 428 is moved to the recording head as shown in FIG. Since the nozzle surface 24a of the 24 nozzles abuts in the direction from the obliquely downward direction toward the head side surface, and the removal member 428 is further lifted as shown in FIG. At this time, the remaining recording liquid DI remaining at the end of the nozzle surface 24a after wiping is scraped off and removed at the tip of the removing member 428.

Next, another example of the removing member will be described with reference to FIG. FIG. 19 is a schematic explanatory view of a cap member provided with the removal member.
In this example, the removal member 528 is formed by integral molding with the cap 122. In this way, the removal member 528 can be disposed only by attaching the cap 122 to the cap holder 421 of the maintenance / recovery mechanism, and the assembling property is improved.

  In the above-described embodiment, the present invention has been described as an example in which the present invention is applied to an image forming apparatus having a multifunction function. However, the present invention can also be applied to a single-function image forming apparatus such as a simple printer, a fax machine, and a copying machine. . Also, the present invention can be applied when using a recording liquid other than ink.

1 is a schematic configuration diagram for explaining an image forming apparatus according to the present invention. FIG. 6 is an explanatory plan view of the image forming unit and the sub-scanning conveyance unit. FIG. 3 is a schematic plan view illustrating a carriage as viewed from the recording head side. It is a perspective explanatory view similarly. FIG. 3 is a schematic explanatory diagram of a head maintenance / recovery mechanism according to the first embodiment of the present invention. It is perspective explanatory drawing which similarly shows a specific structure. It is a side explanatory view similarly. It is expansion explanatory drawing of the cap part of the maintenance mechanism. FIG. 2 is a block explanatory diagram illustrating an overview of a control unit of the image forming apparatus. It is explanatory drawing with which it uses for description of the wiping operation | movement by the maintenance mechanism. It is explanatory drawing with which it uses for description of operation | movement of the removal member by the maintenance mechanism. FIG. 6 is a flowchart for explaining an example of a maintenance / recovery operation in the image forming apparatus. It is a schematic explanatory drawing similarly. It is an expansion explanatory drawing used for description of the surface treatment of a removal member. It is a typical explanatory view including the removal operation process of the maintenance recovery mechanism of the head concerning a 2nd embodiment of the present invention. It is a typical explanatory view including the removal operation process of the maintenance recovery mechanism of the head concerning a 3rd embodiment of the present invention. It is a typical explanatory view including the removal operation process of the maintenance recovery mechanism of the head concerning a 4th embodiment of the present invention. It is a typical explanatory view including the removal operation process of the maintenance recovery mechanism of the head concerning a 5th embodiment of the present invention. It is explanatory drawing which shows the other example of a cap member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Apparatus main body 2 ... Image formation part 3 ... Sub-scanning conveyance part 4 ... Paper feed part 5 ... Paper (recording medium)
6 ... Paper discharge conveyance unit 7 ... Paper discharge tray (paper discharge unit)
DESCRIPTION OF SYMBOLS 11 ... Image reading part 23 ... Carriage 24 ... Recording head 25 ... Sub tank 31 ... Conveyance belt 32 ... Conveyance roller 34 ... Charging roller 121 ... Maintenance recovery mechanism 122a-122e ... Cap 124 ... Wiper blade 128 ... Removal member

Claims (20)

In a head maintenance / recovery device comprising a cap member for capping a nozzle surface of a recording head for discharging a recording liquid droplet, and a wiping member for wiping the nozzle surface.
Removal that is provided along the longitudinal direction of the wiping member and moves up and down with respect to the stopped nozzle surface of the recording head to remove residual recording liquid remaining at the downstream end of the nozzle surface of the recording head in the wiping direction. A head maintenance / recovery device comprising a member.   2. The head maintenance / recovery device according to claim 1, wherein the removing member abuts against a downstream end of the nozzle surface of the recording head in the wiping direction to transfer and remove the remaining recording liquid. apparatus.   2. The head maintenance / recovery device according to claim 1, wherein the removing member slides in contact with the downstream end of the nozzle surface of the recording head in the wiping direction, wipes away the remaining recording liquid, and the side surface of the head. A head maintenance and recovery device, wherein the head maintenance and recovery device is moved.   4. The head maintenance / recovery device according to claim 1, wherein the removing member is an elastic member.   5. The head maintenance / recovery device according to claim 4, wherein the removing member is a mylar.   6. The head recovery device according to claim 1, wherein a surface of the tip of the removal member is subjected to a graining process.   6. The head recovery device according to claim 1, wherein a surface of the tip of the removal member is subjected to a hydrophilic treatment.   8. The head maintenance / recovery device according to claim 1, wherein the water repellency of the surface of the removal member is lower than the water repellency of the nozzle surface of the recording head.   9. The head maintenance / recovery device according to claim 1, wherein the removal member moves up and down in conjunction with the vertical movement of the cap member.   10. The head maintenance / recovery device according to claim 1, wherein the removal member is provided on a suction cap member or a holding member that holds the suction cap member. apparatus.   11. The head maintenance / recovery device according to claim 1, wherein the removal member is provided on a moisturizing cap member or a holding member that holds the moisturizing cap member. apparatus.   The head maintenance / recovery device according to claim 9, wherein the removal member is fixed to a holding member that holds the cap member with an adhesive.   The head maintenance / recovery device according to claim 9, wherein the removal member is fixed to a holding member that holds the cap member by a pressing member.   10. The head maintenance / recovery device according to claim 9, wherein the removal member is formed integrally with the cap member.   15. An image forming apparatus comprising a recording head for discharging recording liquid droplets to form an image, comprising the head maintenance / recovery device according to claim 1. .   16. The image forming apparatus according to claim 15, wherein the recording head includes a nozzle cover that covers a periphery of a nozzle surface, and a water repellent treatment is applied to a surface of the nozzle cover. .   17. The image forming apparatus according to claim 15, wherein after the nozzle surface of the recording head is wiped, an operation of removing residual recording liquid at a downstream end portion in the wiping direction is performed.   17. The image forming apparatus according to claim 15, wherein after the nozzle surface of the recording head is wiped twice, an operation of removing the remaining recording liquid at the downstream end in the wiping direction is performed. apparatus.   The image forming apparatus according to claim 15, wherein the recording liquid has a viscosity of 5 (mPa · s) or more. 20. The image forming apparatus according to claim 15, wherein the recording liquid is a pigment-based ink containing a pigment in a color material.

Images