JP2009101630A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the durability of a head using pigment ink. <P>SOLUTION: The condition of the face surface of the head is predicted from various kinds of conditions and wiping is carried out after applying a solvent to the face surface according to need. Concretely, ordinary wiping is carried out by applying no solvent because the face surface of the head gets wet with the ink right after sucking. The wet wiping is carried out only when printing, only when carrying out dot count wiping controlled by leaving the same as it is or only when carrying out timer wiping when cap leaving alone accumulated time exceeds the predetermined time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a head recovery device and a head recovery method of a recording means having an ink discharge port for discharging ink, and an ink jet recording apparatus for performing the head recovery. More specifically, a wiper for removing ink or the like on the face surface to maintain the head performance and print quality by wiping the surface (hereinafter referred to as the face surface) on which the nozzles of the head that ejects ink are formed. This relates to a wiping device in a printer using the printer.

  Recording devices with functions such as printers, copiers, facsimiles, etc., or recording devices used as output devices such as composite electronic devices including computers and word processors and workstations, paper, cloth, plastic sheets based on recorded information An image (including characters and symbols) is recorded on a recording material (recording medium) such as an OHP sheet. Among them, an ink jet recording apparatus (ink jet recording apparatus) performs recording by ejecting ink from a recording means (recording head) to a recording material, and the recording means can be easily made compact and has high definition. Images can be recorded at high speed, can be recorded on special paper without requiring special processing, running cost is low, non-impact method is low noise, and many types of ink (for example, For example, it is easy to record a color image using a color ink.

  As an energy generating element that generates energy used for discharging ink from the discharge port of an ink jet recording head, an element that uses an electromechanical transducer such as a piezo element, or an electromagnetic wave such as a laser is irradiated to generate heat. There are those that eject ink droplets by a heat generating action, and those that heat a liquid by an electrothermal converter having a heating resistor. Among them, an ink jet recording means (recording head) that discharges ink as droplets using thermal energy can perform high-resolution recording because the discharge ports can be arranged at high density. In particular, a recording head using an electrothermal transducer element as an energy generating element is easy to miniaturize, and IC technology and micro-machining technology with remarkable progress in technology and improvement in reliability in recent semiconductor fields. This is advantageous because it can fully utilize these advantages, can be easily mounted at high density, and is inexpensive to manufacture.

  In addition, there are various requirements for the material of the recording material, and in recent years, development for these requirements has progressed, and paper (including thin paper and processed paper) and thin resin plates (OHP, etc.) that are ordinary recording materials. In addition to the above, a recording apparatus using cloth, leather, non-woven fabric, metal, or the like as a recording material is also used.

  The recording apparatus includes a serial type recording apparatus that performs recording while performing main scanning in the direction crossing the conveyance direction of the recording paper (recording material) and a range of a predetermined width (including the entire width) in the width direction of the recording paper. It can be roughly classified into a line type recording apparatus that records using a recording head having a predetermined length held at a fixed position so as to cover. The present invention can be applied to any type of recording apparatus including these recording methods. In the above-described serial type ink jet recording apparatus, an image (including characters and symbols) is usually recorded by a recording head mounted on a carriage that moves along the recording paper after the recording paper is set at a predetermined recording position. An image is formed on the recording paper by executing a predetermined amount of paper feeding (sub-scanning).

  In the above-described ink jet recording apparatus, foreign matters such as ink droplets, dust, dust, and paper dust may adhere to the head surface of the recording head due to the recording operation, and the head surface is cleaned by a cleaning member in order to remove these foreign matters. (For example, wiping by rubbing) is performed. As the cleaning member, a flexible member such as a rubber blade made of a rubber-like elastic material is usually used. Also, the ink near the discharge port of the recording head dries, and the discharge port may become clogged due to thickening, fixing, and accumulation of ink. Furthermore, clogging of the discharge port may occur due to bubbles or dust generated inside the discharge port (liquid passage). As a method for recovering (preventing, eliminating, etc.) these clogs, for example, a capping member is used to form a sealed system at the ink discharge port, and a pump is used to form a predetermined negative pressure on the discharge port surface (head surface). A suction recovery method is adopted in which ink is forcibly discharged from the ejection port by generating a pressure suction force. In order to remove ink adhering to the head surface by suction recovery, the head surface is also cleaned (wiped off) by a cleaning member.

  Also, as inks used in these ink jet recording apparatuses, conventionally, those using water-based dye inks have been the mainstream, but dye inks are originally so-called weather resistance such as light resistance and gas resistance because the dye molecules are small in the first place. Is insufficient, and the color of the recorded matter changes over time. In recent years, therefore, water-based pigment inks have been put into practical use instead of water-based dye inks. Currently used pigment inks have a pigment particle size of about 100 nm, which is much larger than dye molecules, so even if they are affected by light or ozone, the colorant fading is not noticeable and the weather resistance is Much better than dye inks.

  With respect to such an ink jet recording apparatus, a conventional head recovery apparatus and head recovery method will be described with reference to FIGS. 6 is a schematic front view showing a head recovery device of a conventional ink jet recording apparatus as seen from the front side, and FIG. 7 is a schematic side view showing the head recovery device of FIG. 6 as seen from the side. 6 and 7, reference numeral 1A denotes a mat Bk head that discharges a so-called overlay-type black pigment ink (hereinafter referred to as mat Bk ink) suitable for plain paper, mat paper, and the like. Reference numeral 1B denotes a color head suitable for inkjet glossy paper, photographic paper, and the like, which discharges a so-called penetrating color pigment ink having a low surface tension (here, four colors of black, cyan, magenta, and yellow). These inks of the head 1B often add a resin for fixing the ink on the ink jet recording medium, and these color pigment inks are hereinafter referred to as resin pigment inks. Reference numeral 2 denotes a main scanning carriage that positions and holds the mat Bk head 1A and the color head 1B. Reference numeral 3 denotes a main scanning rail that guides and holds the main scanning carriage 2 in a state in which the mat Bk head 1A and the color head 1B can reciprocate in the direction of arrow A.

  Further, 4A is a rubber cap (cap for mat Bk head) that forms (capping) a sealing system at the discharge port 1Aa of the black head 1A, and 4B forms a sealing system at the discharge port 1Ba of the color head 1B. This is a rubber cap (cap for color head) that performs (capping). The rubber caps 4A and 4B are positioned and held by a holder member (not shown) so as to be movable in a capping direction (arrow B direction) and a non-capping direction (arrow C direction) by a drive source (not shown), thereby A capping unit for the ink head is configured.

  6 and 7, cap absorbing members 9A and 9B for absorbing and holding ink are provided inside the rubber caps 4A and 4B, respectively. Further, in order to prevent the ink from thickening and depositing on the discharge port portions 1Aa and 1Ba, even during recording (printing), the cap absorption members 9A and 9B are spaced from the discharge ports at predetermined time intervals. Pre-voking is performed. 5A is a suction pump (suction means) for the mat Bk head, 5B is a suction pump (suction means) for the color head, and applies a predetermined suction pressure (negative pressure) to the discharge ports 1Aa and 1Ba in the capped state. The suction recovery is performed by forcibly sucking ink from the discharge ports 1Aa and 1Ba through the first tubes 6A and 6B, and discharging the sucked ink to the waste ink processing member 8 through the second tubes 7A and 7B. (Recovery processing) is performed. 10A is a cleaning member for the mat Bk head, 10B is a cleaning member for the color head, and these cleaning members are formed of a rubber member such as urethane, butyl, or silicon, or a porous sponge material. Yes.

  The cleaning members 10A and 10B can be moved in the directions of arrows D and E in FIG. 7 by a drive source (not shown), and are rubbed against the head surface including the discharge port portions 1Aa and 1Ba by the movement in the direction of the arrow D. ((1) → (2) → (3) Dotted line portion) Cleaning (wiping and cleaning) is performed. When the cleaning member 10A, 10B further moves in the direction of arrow D after the cleaning is completed, the cleaning members 10A, 10B come into contact with the cleaners 11A, 11B ((4) dotted line portion). Due to this contact, ink droplets, dust, dust, paper dust and the like scraped from the head surface and adhering to the cleaning members 10A and 10B are collected by being transferred (transferred) to the corresponding cleaners 11A and 11B. The At this time, the caps 4A and 4B of the capping means are moved (retracted) in the direction of arrow C by a drive source (not shown), and are retracted to a position (not shown) that does not interfere with the cleaning members 10A and 10B of the cleaning means.

  Here, in the conventional head recovery device, the head recovery method, and the ink jet recording apparatus that performs the head recovery, there is no problem of durability in each part of the apparatus when using dye ink, but when using pigment ink. Cleaning time when ink is thickened or fixed is shorter than when dye ink is used, thickens or adheres early, and is scraped (or wiped off) by a cleaning member However, even if it is worse than when using dye ink, even if it is cleaned by rubbing against the head surface of the recording means, the ink is deposited in a thin film on the head surface, and the ink is further fixed, and the head is used in the cleaning operation. There was a technical problem that the recovery was not possible or extremely difficult.

  In general, dye molecules are dispersed (dissolved) in an aqueous solution. However, in pigment inks, pigment particles are generally not hydrophilic but hydrophobic, so they do not dissolve in water, so water solubility is imparted. For this purpose, resin, activator, and the like are adsorbed on the pigment particles to impart hydrophilicity as a pigment dispersion and are dispersed in an aqueous solution. Alternatively, it is self-dispersed in an aqueous solution by providing a hydrophilic group at the end of the pigment particle structure itself.

  Since the pigment particles themselves are hydrophobic, they have a property that the discharge port surface is easily squeezed by the pigment ink when the pigment ink is ejected from the recording head as compared with the dye ink. In the case of a so-called resin-dispersed pigment ink in which a pigment is dispersed using the above-described resin, the resin and the resin easily wet the discharge port surface, which is more remarkable. Further, damage (scraping) to the face surface caused by performing the wiping operation described above in a state where the pigment particles are present on the face surface is one factor that makes the face surface easy to get wet.

  When the discharge port surface slips in this manner, the direction of ink discharge becomes unstable, the positional accuracy of ink landing on the recording medium is deteriorated, and the image quality is lowered.

  In order to solve the above problem, if a recording head that performs so-called water-repellent treatment that repels pigment ink on the ejection port surface of the recording head is used, the direction of ejection is stabilized at the beginning, but basically the liquidity of pigment ink or the like When easy-to-use ink is used, the water repellency gradually deteriorates and the direction of ejection becomes unstable. Alternatively, even wiping performed to maintain the ejection characteristics of the recording head results in spreading easily squeezed pigment ink on the ejection port surface, so that its water repellency deteriorates and image quality deteriorates.

  Alternatively, as disclosed in Japanese Patent Laid-Open No. 11-334074, a head in which only the periphery of the discharge port is made hydrophilic from the beginning has been proposed as a head for pigment ink.

  However, properties such as water repellency or hydrophilicity of the discharge port surface cannot be maintained for a long period of time and deteriorate with time. Even relatively well known UV ozone treatment or the like has hydrophilicity immediately after the treatment, but the degree of hydrophilicity may change with time.

  To solve such a problem of change in water repellency or hydrophilic performance of the face surface, a so-called wet wiping technique as shown in, for example, JP-A-10-138502 is known. This is because the wiper that wipes the face surface is attached with a very low-volatile solvent such as glycerin or polyethylene glycol (hereinafter referred to as wet liquid), and the face surface is wiped with the wiper, thereby making the face wettability. It is intended to prevent changes. The wet liquid has the action of first dissolving the ink thickener and the film thickener accumulated on the face, and secondly acting as a lubricant by interposing between the wiper and the face. Third, a film for protecting the face is formed by attaching a wet liquid to the face.

  As described above, when the head face surface is dried, the ink solvent and the colorant adhere to the periphery of the nozzle, and the surface state (water repellency, shape, etc.) changes. In order to reduce this change, Japanese Patent Laid-Open No. 7-148934 discloses a recording head that detects the elapsed time since the head was last used or maintained, and performs maintenance (wiping) after a certain period of time. It is intended to make it easy to remove deposits by wiping by applying ink to the face surface of the material and then wetting the dried face surface (hereinafter referred to as wet wiping). Therefore, the above control is performed by using a timer / timer reset circuit and a controller.

  On the other hand, there is a proposal of a method for cleaning a wiper member that wipes the face surface of the head. In JP-A-4-232754, an ink droplet ejected from a recording head is sprayed on a wiper blade as a solution, and the solidified ink adhered to the wiper blade is redissolved to prevent clogging due to secondary transfer. It is what. Furthermore, Japanese Patent Application Laid-Open No. 2001-54949 is devised to monitor waste time and control the amount of spraying according to the leave time to suppress wasteful solution (ink) consumption. Accordingly, there is provided means for measuring the wiper leaving time, means for controlling the spraying amount of the solution (ink), and means for controlling the spraying amount according to the leaving time.

Further, Japanese Patent Application Laid-Open Nos. 10-138502 and 10-146985 have proposed devices that perform wiping using a dedicated wiping liquid for refreshing the head face surface.
JP-A-11-334074 JP-A-10-138502 Japanese Patent Laid-Open No. 7-148934 JP-A-4-232754 JP 2001-54949 A JP-A-10-138502 Japanese Patent Laid-Open No. 10-146985

  In recent years, apparatuses using improved dye inks and pigment inks as colorants that are highly storable have been used in order to improve the storability of images. Such an ink system has high water resistance in order to improve image storability, and it is difficult to redissolve the ink after it has dried. Therefore, re-dissolution using ink does not cause a problem immediately after its implementation, but in the long term, the colorant is not preferable because it causes secondary problems. Also, because of the need to record ultra-small droplets (4 pl or less) with ultra-high speed drive (15 KHz or more) in order to improve image quality, if the state of the recording head face is bad, the ejection direction changes and this affects the image quality. Come. Therefore, a special redissolving solution is required to withstand long-term storage (hard to evaporate) and always realize an optimal face surface. It is desirable that the dedicated liquid has a solvent structure that does not affect the discharge of the recording head even if it is mixed in the nozzle. Further, it has become necessary to remove the dry ink adhering to the face surface of the head from the face surface of the head within a time during which re-dissolving is possible. In addition, the image quality, speed, and miniaturization of the device has further increased, and the number of colors and nozzles has increased, increasing the face area of the head while retaining a large amount of dedicated solution for cleaning the face surface. It is not desired to do. It is important to uniformly apply the redissolved solution over a wide area. If the coating is uneven, a difference in ejection performance depending on the state occurs, which affects the image quality. Accordingly, there is a need for a wet wiping method that can be mounted even in a small apparatus in space, has high uniform reproducibility of the coating amount in the coating process, and can efficiently remelt and refresh the face surface with a small amount of coating.

  When the ink on the recording head face of the ink jet recording apparatus dries and the ink is solidified and thickened, the water repellency, surface condition (unevenness, etc.) of the recording head face, change in nozzle shape, and the like occur. As a result, twisting or non-discharge occurs when ink droplets are ejected from the nozzles. In order to prevent this, a suction or winding means is generally provided as means for keeping the face surface constant. However, when special ink with improved image storability is used, the surface condition of the face surface changes drastically. To cope with this, a wiping means for refreshing the face surface after further applying ink or solvent is provided. A method of providing (hereinafter referred to as wet wiping) has been proposed. When wiping is performed each time by this method, a large amount of coating agent is required to secure a coating amount corresponding to the life of the main body, resulting in an increase in size and cost of the apparatus.

  The state of the face surface of the head is predicted from various conditions, and if necessary, a solvent is applied to the face surface before wiping is performed. Specifically, since the face surface of the head is wet with ink immediately after suction, normal wiping is performed without applying solvent. Wet wiping is performed only during dot wiping, which is controlled during printing or by leaving, or when timer wiping is performed when the accumulated cap leaving time exceeds a predetermined value. Furthermore, in the case of Bk single color, we looked at the state of one nozzle row, but at least 3 colors were used when performing color recording, 4 colors when using UCR, 6 colors when forming a photo image, 8 An image is formed using a number of ink nozzle arrays such as colors. At this time, when it is determined that the head face surface of at least one ink / nozzle row is dry while monitoring the usage status of each ink / nozzle row by the dot count and the standing time, at least the necessary portion (area) is wet. Control to perform wiping.

As described above, according to the present invention,
The minimum number of implementations required even when wiping means (wet wiping) that always refreshes the face surface is necessary, such as when using special ink with improved image preservation, and the face surface changes drastically. Since it is possible to select the optimal recovery method only when it is really necessary, it is sufficient to secure the minimum amount of coating agent, while keeping the device downsized, low cost, high weather resistance, high durability and high reliability. Sex can be achieved at the same time.

  Next, details of the present invention will be described in accordance with the description of the embodiment.

(First embodiment)
The first embodiment of the present invention will be described in detail below.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of an ink jet recording apparatus employing wet wiping according to the present invention. In FIG. 1, 35 is a recovery device including a wet wiping mechanism, and 36 is a temperature detection member provided in the vicinity of the recovery device and in the main body side plate. Here, a thermistor is used.

  [1] Outline of operation of main body, [2] Outline of recovery device, [3] Outline of recording head, [4] Detailed operation description of recovery device including wet wiping, [5] Important about wet wiping The wet wiping mechanism used in the present invention will be described in the order of description of the portions, and an embodiment relating to the control of the wet wiping mechanism according to the temperature by the 36 temperature detection member will be described later as an embodiment.

[1] Explanation of schematic operation of main body In FIG. 1, a recording material 30 such as a recording paper is fed into the apparatus main body by a paper feed roller 31, and is pinched on a paper feed roller (conveying roller) 32 (not shown). And a front surface of the recording means (recording head) 1 composed of the mat Bk head 1A and the color head 1B by controlling the rotation of the paper feed roller 32. The paper is fed (conveyed) through a position (recording position) with a predetermined gap from the head surface provided on the head, and an image (including characters and the like) is driven by driving the recording head 1 based on the recording information during that time. Recorded (printed). The home position HP of the main scanning carriage 2 is set at a position within the moving range of the main scanning carriage 2 and out of the recording area (right end portion in the figure).

[2] Outline of the recovery device In the vicinity of the home position HP, the discharge port is sealed by contacting (contacting) the head surfaces (surfaces on which the discharge ports are formed) of the mat Bk head 1A and the color head 1B. Capping means having rubber-like elastic caps 4A, 4B that can be used, suction means including a suction pump that can generate a negative pressure suction force through the caps 4A, 4B in the capped state, and the mat A head recovery device 35 including a cleaning unit including a cleaning member for scraping (wiping off) an adhering matter such as ink and dust by rubbing against the head surfaces of the Bk head 1A and the color head 1B is disposed. . The head recovery device 35 generates a negative pressure in the cap by a suction pump in a state where the discharge port portion of the head is capped, and this negative pressure causes ink such as thickened ink, bubbles, fixed ink, and dust from the discharge port. This is for executing a recovery operation for recovering the ink ejection performance of the head by sucking out and removing the foreign matters.

[3] Outline of recording head The mat Bk head 1A and the color head 1B as recording means (recording head) 1 are ink jet recording heads that eject ink using thermal energy, and generate thermal energy. For this purpose, an electrothermal converter is provided. Further, the recording means 1 causes film boiling in the ink by the thermal energy applied by the electrothermal transducer, and ejects ink from the ejection port using the pressure change caused by the growth and contraction of bubbles generated at that time. And recording (printing including printing).

[4] Detailed Operation Description of Recovery Device Including Wet Wiping The recovery device 35 in FIG. 1 includes a wet wiping unit, which will be described in detail in the following description of the recovery device. The basic mechanical configuration and sequence operation of the recovery device 35 and wet wiping using the recovery device 35 are the same as those described in the conventional example, and will be described with reference to FIGS.

  FIG. 6 shows the state of the recovery device when the recording apparatus is powered off or in standby. The mat Bk head 1A (ink ejection port 1Aa) faces the cap 4A for the mat Bk head and the color head 1B. FIG. 4 is a schematic front view of the head recovery device 35 in a capping state in which the ink discharge port 1Ba is opposed to the color head cap 4B.

  Normally, when the printer power is turned off or when the printer is on standby, the cap is in such a head protection position to prevent dust from adhering to the ejection port of the head and evaporation of moisture from the ejection port. . When the print signal is received, the cap 4A for the mat Bk head and the cap 4B for the color head are lowered in the direction of the arrow C in FIG. 6, and the cap is opened, and the carriage is operable. FIG. 8 is a schematic side view of the recovery device 35 in the cap open state.

  Printing is performed by scanning the carriage 2 along the main scanning rail 3. As a recovery operation during printing, preliminary ejection onto the cap can be mentioned. 9A and 9B are ink absorbing members provided in the caps 4A and 4B, and these ink absorbing members 9A and 9B are formed of a porous material or a sponge-like material capable of absorbing and holding ink. Has been. In the cap open state during printing, the caps 4A and 4B are positioned and held at positions separated from the heads 1A and 1B. In the cap open state, the ejection ports 1Aa and 1Ba of the heads 1A and 1B are directed toward the ink absorbing members 9A and 9B. Thus, preliminary ejection for ejecting ink is performed.

  This preliminary discharge is an operation for preventing the ink in the discharge port portions 1Aa and 1Ba from being thickened and fixed during recording, and is usually performed at predetermined time intervals. This preliminary discharge may be performed toward a preliminary discharge receiving means (not shown). This preliminary discharge receiving means can be composed of, for example, a container or an ink absorbing member.

  Next, a normal head recovery operation will be described with reference to FIGS. 5A is a suction pump (suction unit) for the mat Bk head, and 5B is a suction pump (suction unit) for the color head. As shown in FIG. 6, in a capping state in which the caps 4A and 4B are in contact (contact) with the heads 1A and 1B, a predetermined negative suction pressure (suction force) is generated at the discharge ports 1Aa and 1Ba of the heads 1A and 1B. Thus, the ink is forcibly sucked from the discharge ports 1Aa and 1Ba via the first tubes 6A and 6B, and the sucked ink is discharged to the waste ink processing member 8 via the second tubes 7A and 7B. Suction recovery is performed. The suction pumps (suction means) 5A, 5B are for performing such suction recovery. This suction recovery is performed in consideration of necessity, such as immediately before the start of recording, every predetermined amount of time or during recording, or when it is detected that a head recovery operation is required. Is.

  In FIG. 8, 10A is a cleaning member (cleaning means) for the mat Bk head, 10B is a cleaning member (cleaning means) for the color head, and these cleaning members are rubber-like members such as urethane, butyl, and silicon, It is formed of a porous member and a sponge member. The cleaning members 10A and 10B can be moved in the directions of arrows D and E by a drive source (not shown), and the head surface including the discharge port portions 1Aa and 1Ba (the discharge port surface on which the discharge ports are formed) by moving in the arrow D direction. ) Is wiped off (operation (1) → (2) → (3) in FIG. 8), and the head surface is cleaned (by wiping or the like). When the cleaning is completed and further moved in the direction of arrow D, the cleaning members 10A and 10B come into contact with the cleaners 11A and 11B (position (4)). That is, when the cleaning members 10A and 10B come into contact with the cleaners 11A and 11B, ink droplets, dust, dust, and paper dust scraped from the head surface (discharge port surface) are transferred from the cleaning members 10A and 10B to the cleaners 11A and 11B. It is transferred to and collected. At this time, the caps 4A and 4B are moved in the direction of arrow C by a drive source (not shown), and are retracted to positions (not shown) that do not interfere with the cleaning members 10A and 10B.

  FIG. 8 shows the structure of wet wiping. A wet wiping unit is provided near the wiper folding position on the right side of the wiper cleaning members 11A and 11B. 20 is a wet liquid holding section, 21 is a wet liquid transmission section, and 21a is a contact section where the wiper comes into contact and attaches the wet liquid to the weighter. The wiper is cleaned by the wiper cleaning members 11A and 11B from the left side in the drawing, and then passes through the cleaning member to reach the wet wiping unit (operation (4) → (5) → (6)). The wiper reciprocates left and right, but is arranged so that the wiper hits the contact portion as shown in FIG. Then, the wet liquid is transferred in accordance with a predetermined nip width at the contact portion.

  After the transfer of the wet liquid, the wiper returns again from (6) to (1) and stops at the wiper standby position. However, at this time, the wiper cleaning members 11A and 11B are provided so as to be retracted by a mechanism (not shown). The carriage 2 is also moved from the wiping position so that the face surface of the head is not wiped on the surface opposite to the wiping surface of the wiper. That is, the wiper returns to the stop position (1) by the operation of (6) → (5) → (3) → (1).

  In the system as described above, at the time of the first wiping, the wiping is actually performed while the wet liquid is not transferred to the wiper. Will do. Here, since the wet liquid is very difficult to evaporate, it does not evaporate and disappear at the next wiping. Further, since the wet liquid has a viscosity much higher than that of ink used in a normal ink jet printer, it does not flow out after adhering to the wiper. In addition, the change in the state of the face due to dry wiping only once (wiping without using wet liquid) is negligible compared to the number of wiping durability during the main body life.

  The present invention is not limited to the above-described configuration, and is also effective for an inkjet printer having a wet wiping mechanism using a rotating wiper as disclosed in Japanese Patent Laid-Open No. 10-138502. It is also effective for other configurations in which the wiper slides as described above. Specifically, in the slide wiper system as described above, a wrapping position is provided between (5) and (6), and from there, it is possible to return to the stop position of (1). Wiping including the transfer step (step of moving to the position (6) and then returning to (1)) and not including the transfer of the wet liquid (turning back to the position (1) at the positions (5) and (6)) ) A wiping step, the present invention is effective even in such a system.

[5] Explanation of important parts related to wet wiping In the system having the above recovery mechanism, particularly important elements related to the structure of wet wiping, that is, wet liquid and its holding / transmitting part, the state of the face face of the head, The ink used is as follows.

  In FIG. 8, reference numeral 20 denotes a wet liquid holding unit, which holds the wet liquid with a sponge fiber (hereinafter referred to as PP sponge). The fiber diameter of the polypropylene fiber, the apparent density when the fiber is spongy, the orientation direction of the fiber in the sponge, the compressibility when the sponge is incorporated in the apparatus, and the like may be selected as appropriate. Reference numeral 21 denotes a transmission member that transmits the wet liquid from the PP sponge 20 of the wet liquid holding section and transmits the wet liquid to the wiper contact portion of 21a, and includes the contact portion 21a. Here, as the transmission member 21, Asahi Kasei Sun Fine AQ900 is used. Here, in order to ensure that the wet liquid is supplied between the wet liquid holding unit 20 and the transmission member 21, the capillary force of the transmission member 21 is greater than the capillary force of the wet liquid holding unit 20 with respect to the capillary force. Must be stronger. While maintaining such a relationship, the average pore diameter, apparent density, capillary force and the like of the transmission member may be appropriately selected.

  Here, the wipers 10A and 10B are made of polyether urethane, and the head face surface is a water repellent head coated with a water repellent material.

  Although glycerin is used here as the wet liquid, glycerin itself is difficult to evaporate, but it is easy to absorb moisture in the air, and even when it absorbs moisture, it releases moisture and dries in a low humidity environment. Therefore, it is preferable to shield the outer periphery of the wet liquid holding unit 20 and the transmission member 21 in FIG. 8 with a material having low water vapor permeability (not shown) so as not to be affected by moisture absorption and drying.

  However, it is desirable not to be completely sealed but to provide a part of air communication pores so as to withstand the expansion and contraction of air existing in the wet liquid holding part.

  As the ink to be used, as described in the conventional example, a self-dispersible matte Bk pigment ink is used for the 1A head. This is an ink in which pigment particles are self-dispersed in an aqueous solution by providing a hydrophilic group at the end of the structure of the pigment particles. On the other hand, color pigment inks (black, cyan, magenta, yellow) are used for the head 1B, and these are inks in which pigment particles are dispersed in water with a resin having a surfactant action.

  Further, the size of the wet liquid holding part, that is, the volume of the holding part calculated backward from the required amount of the wet liquid can be calculated as follows. First, even if wet wiping equivalent to the durable number of ink jet printers installed is performed, there is no significant change in the water-repellent state of the face, and the transfer of wet liquid that is necessary because the landing position accuracy of the discharged droplets is within the allowable range It is necessary to obtain a volume by an experiment or the like, and to have a volume capable of holding the wet liquid by multiplying this by the number of wipings corresponding to the durable number.

  For example, in the system shown above, 1 mg of glycerin is transferred to a wiper in one wet wipe, and then applied to the face surface of the water-repellent head, and the target durable number of 10,000 sheets can be achieved without any problem. Then, the amount of glycerin required between the durable sheets is 10 g.

  Considering the density of glycerin, the amount of glycerin retained by the PP sponge, the amount of glycerin retained by the transmission member, the remaining amount when the glycerin is used up, the volume of the glycerin retaining portion needs to be about 20 cc. The initial glycerin injection amount depends on the exhaustion efficiency, but normally 100% can not be used up, so it is necessary to inject about 1.2 times the required amount. Of course, these conditions, that is, the amount of glycerin required for one wiping, the number of durable sheets, and the amount of glycerin retained in the PP sponge and transmission member differ depending on the requirements of each printer and should be set appropriately. .

  It should be noted that the present invention is not limited to the above-described form, and includes materials such as a wet liquid, a wet liquid holding portion, a transmission member, water repellent / non-water repellent / hydrophilicity in a face state, etc. Various changes such as the ink surface tension, which is an index of ink wettability, and the contact angle of the ink with respect to the face, can be made and can be transformed into various forms. Of course, in the present specification, the case of using a pigment ink is also given as an example of the ink, but the present invention can also be applied to a dye ink.

  Hereinafter, various embodiments relating to control of the transfer amount of wet liquid to a wiper under a low temperature environment, which is a characteristic configuration of the present invention, will be described.

(Configuration 1)
As a wiping configuration, the normal wiping and the normal wiping + wet wiping can be switched by the movement amount of one operation. When the movement amount is small, normal wiping is performed, and when the movement amount is large, normal wiping + wet wiping is performed.

(Configuration 2)
As the wiping configuration, the wet wiping dedicated liquid application unit moves up and down, and the normal wiping and normal wiping + wet wiping can be switched by moving up and down. When rising, normal wiping and when descending, normal wiping + wet wiping .

(Configuration 3)
As the wiping configuration, the wet wiping liquid application unit rotates, the normal wiping and the normal wiping + wet wiping can be switched by the rotating operation, the normal wiping at the rotation position 1 and the normal wiping at the rotation position 2 Wet wiping.

(Second Embodiment)
It is assumed that the wet wiping is performed only at a predetermined timing.

  The purpose is to achieve downsizing, cost reduction, and long life by implementing necessary and sufficient wet wiping.

  Stated that the amount of dedicated liquid for wet wiping is reduced compared to wet wiping every time.

  Table 1 shows the state of the head face as Table 1. This table was created in advance by varying the parameters of the wetness of the face (number of dots) / printing duty per unit time, ink color, leaving time, and leaving environment. Tables 2 and 3 show the table 2 (remaining time and return performance table) and 3 (dot count difference and return performance table) that can be recovered from each surface condition. With reference to this table (the actual table needs to be reviewed: the provisional table is explained), the wiping method can be selected from the following control conditions based on the table.

  The following four examples will be described as examples in connection with the normal wiping operation and the wet wiping operation described above.

・ Example 1: In the case of a suction sequence after being left out Wet wiping is not performed because the face surface is wet with mist due to residual ink remaining on the face surface after suction or pre-discharge of mixed colors (the number of pre-discharges is very large) .

-Example 2: In the case of a dot count suction sequence between pages that are being printed The face surface is wet with mist due to residual ink remaining on the face surface after suction or pre-discharge of mixed colors (the number of pre-discharges is very large) So do not perform wet wiping.

・ Example 3: In case of dot count wiping / timer wiping sequence When there is little difference in dot count of each color at the time of dot count wiping, there is no problem with normal wiping because the whole is wet with mist. On the other hand, when there is a dot count difference of each color at the time of timer wiping and there is a color with a relatively low printing duty, the face surface is sparsely soiled with ink depending on the position. Since the wiping at this time has a long standing time, it is assumed that drying is progressing. In this case, it is desirable to perform wet wiping before normal wiping. Further, when the printing duty is low overall, there is a high possibility that the face surface is completely dried. Also in this case, it is desirable to perform wet wiping before normal wiping. Depending on the conditions after the tank replacement sequence and cover open, the head face is forcibly dried. Also in this case, it is desirable to perform wet wiping before normal wiping.

・ Example 4: Wiping sequence before closing cap When closing cap without printing after leaving, depending on the conditions, it can be determined whether or not it is implemented by managing the leaving time. Also, when the print duty is relatively low even when waiting for print data and the cover is opened directly or halfway after printing, it is better to carry it out depending on the leaving conditions.

(Control 1)
Check the wet state of the face face of the head in advance by dot count, and if the difference in the number of dots by printing each color is within a certain value, perform normal wiping when the number of dots of a certain color reaches the specified value When the difference in the number of dots due to printing of each color reaches a certain value or more and the number of dots of a certain color reaches a predetermined value, normal wiping + wet wiping is performed. When the difference in the number of dots due to printing of each color reaches a certain value and exceeds a certain time, normal wiping + wet wiping is performed.

(Control 2)
Check the wet state of the face face of the head in advance using a timer based on two conditions, the environment, and if the time for each color is within a certain value, Normal wiping is performed, and when a certain color is left for a certain time or more and under certain environmental conditions, normal wiping + wet wiping is performed. When the standing time of each color reaches a certain level, normal wiping + wet wiping is performed.

In addition,
FIG. 2 is a diagram illustrating a wet wiping mechanism according to the first embodiment.

  FIG. 3 is a diagram illustrating a wet wiping mechanism according to the second embodiment.

  FIG. 4 is a diagram illustrating a sequence flow of wet wiping in the third embodiment.

  FIG. 5 is a diagram illustrating a sequence flow of wet wiping in the fourth embodiment.

It is a schematic block diagram of the inkjet recording device of this invention. It is a figure explaining the wet wiping mechanism in Example 1. FIG. It is a figure explaining the wet wiping mechanism in Example 2. FIG. FIG. 10 is a diagram illustrating a sequence flow of wet wiping in the third embodiment. It is a figure explaining the sequence flow of the wet wiping in Example 4. FIG. It is a cross-sectional block diagram of a recovery system of a conventional ink jet recording apparatus. It is a block diagram of another cross section of the recovery system of the conventional ink jet recording apparatus. It is a figure explaining the conventional wet wiping mechanism.

Explanation of symbols

1A Matt Bk head 1B Color head 2 Main scanning carriage 3 Main scanning rail 4A Cap for mat Bk head (capping means)
4B Color head cap (capping means)
5A, 5B Suction means (suction pump)
9A, 9B Ink absorbing member 10A Cleaning member (cleaning means) for mat Bk head
10B Color head cleaning member (cleaning means)
11A, 11B Cleaner 1Aa, 1Ba Discharge port (discharge port)
1a, 1b Discharge port (discharge port)
30 Recording material (recording paper, etc.)
Reference Signs List 31 Paper feed roller 32 Paper feed roller 35 Head recovery device 36 Temperature detection member 20 Wet liquid holding part 21 Wet liquid transmission part 21a Wiper contact part

Claims (3)

A recording head having an ejection port for ejecting ink; and a wiper member as a wiping means for wiping the ejection port surface of the recording head, and the recording head and the wiper member move relative to each other, An inkjet recording apparatus for wiping the discharge port surface of a recording head,
As a means for maintaining the state of the discharge port surface of the recording head, it has a processing liquid holding unit that stores a processing liquid dedicated to wiping, and an application unit that applies the processing liquid to the recording head or the wiper member.
While maintaining the state of the discharge port surface by wiping the discharge port surface of the recording head using the processing liquid,
An ink jet recording apparatus comprising: a recording head member, a wiping member, a wet wiping-dedicated solvent, a solvent holding member, and a solvent application unit.   2. The ink jet recording apparatus according to claim 1, wherein wet wiping is performed when a predetermined condition is improved in the above configuration.   2. The ink jet recording apparatus according to claim 1, wherein the predetermined condition is defined by a leaving time, a leaving environment, and a pre-leaving condition.

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