JP2009101632A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem, in an inkjet recording device which performs recording by a recording head ejecting an ink on a recording medium, that wet wiping is not effective unless it is coated with a wet wiping solution of more than a certain amount because a transfer amount of the wet wiping coating the head changes with an environmental temperature as a viscosity of the wet wiping solution (glycerin as an example) greatly changes with an environmental temperature. <P>SOLUTION: The temperature of the wet wiping solution is always kept constant by heating the wet wiping solution, so that the transfer amount is kept in a certain amount or more. <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 there is a problem that the color of the recorded matter changes with 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. FIG. 2 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. 3 is a schematic side view showing the head recovery device of FIG. 2 as seen from the side. 2 and 3, 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 in the discharge port 11 of the black head 1A, and 4B forms a sealing system in 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.

  2 and 3, 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 sticking to the discharge port portions 11 and 1Ba, even during recording (printing), the cap absorbing 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 port portions 11 and 1Ba in the capped state. The suction recovery is performed by forcibly sucking ink from the discharge ports 11 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. 3 by a drive source (not shown), and are rubbed against the head surface including the discharge port portions 11 and 1Ba by the movement in the direction of arrow D. ((1) → (2) → (3) dotted line) Perform cleaning (wipe clean). 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 will be described in detail later, an example of a wet wiping configuration will be described below.

  FIG. 4 shows the configuration of wet wiping, and is obtained by adding a wet wiping unit to FIG. A wet wiping unit is provided near the wiper folding position on the right side of the wiper cleaning members 11A and 11B. Reference numeral 20 denotes a wet liquid holding part, and 21 denotes an abutting part where the wiper abuts and attaches the wet liquid to the weir. A heating mechanism 22 for heating the wet liquid is provided near the contact portion 21 by a driving source (not shown). 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 adheres at the contact portion according to a predetermined nip width (hereinafter, the movement of the wet liquid from the contact portion to the wiper and the adhesion to the wiper is referred to as “wet liquid transfer”). It is what I did.

  However, the present inventors examined the performance change of the face face of the head with the above-mentioned wet wiping installed, and the effect of the wet wiping is small especially in a low temperature environment, and the face state changes compared to the initial state. I understood that. For this reason, it has been found that the landing accuracy of the discharged droplets deteriorates, resulting in disturbing the print quality.

  When the behavior under such a low temperature environment was examined, it was found that the amount of the wet liquid transferred to the wiper varied greatly depending on the environment. Since the wet liquid should be kept in the main unit for the life of the main unit in the first place, one with a low saturated vapor pressure in air, that is, one that does not easily evaporate, is preferred, and solubility in ink thickeners In view of the wettability with each member and the head, polyhydric alcohols such as glycerin and polyethylene glycol, which are often used as an ink composition of an ink jet printer, are preferable. Since many of these solvents generally have a large molecular weight and a high viscosity, the degree of increase in viscosity under a low temperature environment is also large. FIG. 8 shows a temperature viscosity curve of glycerin as an example. Viscosity of about 800 cp at room temperature, 2300 cp at 15 ° C, and 7000 cp at 5 ° C, the viscosity increases rapidly as the temperature decreases.

It is considered that the transfer amount of the wet liquid decreases due to the increase in viscosity (thickening) of the wet liquid in such a low temperature environment. It is considered that the wet liquid is insufficient due to the viscosity, or that the wet liquid is difficult to tear off from the contact portion because the viscosity of the wet liquid is large when the wiper returns after the contact.
JP-A-11-334074 JP-A-10-138502

  As described above, an inkjet printer equipped with wet wiping has a problem in that the amount of wet liquid transferred to the wiper varies greatly depending on the environment. In other words, in a low temperature environment, the transfer amount decreases from room temperature due to the increase in the viscosity of the wet liquid, so that the effect of the predetermined wet wipe cannot be exhibited, and the performance of the face after durability deteriorates and the print quality deteriorates. .

  This case has been made to solve the above-mentioned problems. When printing is performed in an ink jet recording apparatus, the temperature of the wet liquid is adjusted and the temperature is kept constant, so that the viscosity always increases due to thermal fluctuations at any environmental temperature. The required amount of wet liquid is transferred to the wiper and can be applied to the recording head, and high quality printing is always possible in any environment.

  In order to solve the above problems, the present invention has the following configuration.

In an ink jet recording apparatus that performs recording using a recording head that performs recording by discharging ink onto a recording medium, a cleaning member for wiping off dirt and the like adhering to the recording head, and a coating liquid for cleaning the recording head And a holding means for holding the coating liquid in the previous period, a temperature measuring means for measuring the temperature of the coating liquid, and a judging means for judging whether the coating liquid needs to be heated by the temperature measuring means, It has a heating means for heating the coating solution and a heat retaining means for keeping the temperature at a predetermined temperature,
Further, the heating means is characterized in that it is in the vicinity of an isocontact portion between the cleaning member and the coating liquid holding means,
In addition, while the power is on, the coating solution is kept warm,
In addition, the coating liquid is heated only at a predetermined timing during power ON.

  As described above, according to the present invention, by keeping the temperature of the coating liquid constant, at the start of printing, by changing the temperature of the wet liquid to a predetermined temperature, the viscosity change is eliminated, and the recording head is This makes it possible to apply the required amount of wet liquid, reducing the occurrence of ink sticking and filming in the vicinity of the nozzles in the recording head, which was a problem when using pigment ink, and always provides high-quality printing. Can be done. In addition, power consumption can be saved by limiting the heating time.

  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] Description of schematic operation of main body In FIG. 1, a recording material 30 such as a recording paper is fed into the main body of the apparatus by a paper feed roller 31, and a pinch roller (not shown) on a paper feed roller (conveyance roller) 32. 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 of FIG. 1 includes a wet wiping unit, which will be described in detail in the description of the recovery device below. 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. 2 shows the state of the recovery device when the recording apparatus is powered off or in standby. The mat Bk head 1A (ink discharge port 1Aa) is opposed to the mat Bk head cap 4A, 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 arrow C in FIG. 2, and the cap is opened, and the carriage can be operated. FIG. 4 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. 2, 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. 4, 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. 4), 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. 4 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 from (6) to (1) again 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 shown in the above-mentioned JP-A-10-138502, or This 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), so that the wet liquid Wiping including the transfer process (the process of moving to the position (6) and then returning to (1)) and the transfer of the wet liquid is not included (turn 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. 4, 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. 4 with a material having a 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. 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.

  First, the first embodiment in the characteristic configuration of the present invention will be described.

As shown in FIG. 8, the viscosity of glycerin, which is an example of the wet liquid, increases as the temperature decreases. Therefore, in a low temperature environment, the viscosity becomes high, and the amount of wet liquid necessary for performing wet wiping cannot be transferred to the wiper. Therefore, it is difficult to remove the pigment ink from the ink head, and high-quality printing cannot be performed. In the first embodiment, the following control operation is performed in the ink jet recording apparatus in which the amount of wet wiping applied to the recording head is substantially constant when performing wet wiping.
This first embodiment will be described with reference to FIGS. 4 and 5.

  First, in STEP-A1, the environmental temperature Tw is measured by the temperature detection member 36 in FIG. Next, in STEP-A2, it is determined whether the environmental temperature Tw is higher than the threshold temperature Th. If the environmental temperature Tw is higher than the threshold temperature Th, normal printing is performed as it is. If the environmental temperature Tw is lower than the threshold temperature Th, the process proceeds to STEP-A3, where the wet liquid is heated by the heating mechanism of FIG. In this heating mechanism, as long as the power is turned on, this heat retention is continued, and a predetermined amount of wet liquid is always transferred to the wiper so that it can be applied to the recording head.

  Here, as an example of the threshold temperature Th, Th = 25 degrees. With this viscosity, a coating amount necessary for the recording head can be obtained.

  Here, as an example of the predetermined temperature of the wet liquid heated by the heating mechanism, the temperature is set to 25 ° C. Thus, when the viscosity is maintained at around 800 cp, a predetermined amount of wet liquid can be applied to the recording head. Of course, the temperature to be heated by this heating mechanism is not limited to this temperature, and is preferably set to a temperature suitable for each.

  Here, as an example, as shown in FIG. 4, a heating mechanism is provided only in the vicinity of the wiper contact portion of the wet liquid holding portion. Since this method only requires heating a part of the wet liquid, the wet liquid can be heated more quickly. However, the position of the heating mechanism is not particularly limited here, and may be installed anywhere as long as the wet liquid can be heated.

  In addition, as an example this time, in FIG. 4, the wet liquid holding unit and the wiper are in contact with each other horizontally, but this contact part is not limited to horizontal, and has an angle so that the wet liquid holding unit and the wiper are in contact with each other. The contact area of the wiper may be increased.

  In this way, when the power is turned on, the ambient temperature is measured, and the wet liquid temperature is set to a predetermined temperature, thereby eliminating the viscosity change and performing the wet wiping, so that the necessary amount of wet is applied to the recording head. The liquid can be applied, and even when pigment ink is used, it is possible to reduce the occurrence of ink sticking and film tension on the face surface of the recording head, and always perform high-quality printing.

  A second embodiment of the characteristic configuration of the present invention will be described.

  In the second embodiment, the following control operation is performed in an inkjet recording apparatus capable of wet wiping. If the wet liquid is always warmed as in the first embodiment, optimum printing can be performed at any time, but power is continuously consumed while the power is on. Therefore, when printing is started, it is determined whether heating is necessary, overheating from the start of printing is performed, and power consumption in the time from the power ON to the start of printing is suppressed.

  The second embodiment will be described with reference to the flowchart of FIG.

  When the print command is issued, first, in STEP-B1, the environmental temperature Tw is measured by the temperature detection member 36 in FIG. Next, in STEP-B2, it is determined whether or not the environmental temperature Tw is higher than the threshold temperature Th. If the environmental temperature Tw is higher than the threshold temperature Th, the process proceeds to STEP-B4. On the other hand, when the environmental temperature Tw is lower than the threshold temperature Th, the process proceeds to STEP-B3, the wet liquid is heated by the heating mechanism of FIG. 4, is raised to a predetermined temperature, is kept warm, and the process proceeds to STEP-B4. Next, in STEP-B4, it is determined whether suction recovery is necessary. If suction recovery is not required, proceed to STEP-B6. If suction recovery is necessary, proceed to STEP-B5, perform suction recovery, and proceed to STEP-B6. Next, wet wiping is performed in STEP-B6, and printing is performed in STEP-B7. Next, proceeding to STEP-B8, it is determined whether print data has been received. If print data is not received, the process proceeds to STEP-B9. If print data is received, the process proceeds to STEP-B7 and printing is continued. Next, in STEP-B9, it is determined whether a predetermined time has been waited. If the predetermined time has not elapsed, the process proceeds to STEP-B8, and the standby is continued. If the predetermined time has elapsed, the process proceeds to STEP-B10. In STEP-B10, wet wiping is performed to remove ink adhering to the recording head. Next, in STEP-B11, perform capping and wait.

  Here, the wet liquid is kept warm until the power is turned off, and the next print data is awaited.

  Here, as an example of the predetermined temperature of the wet liquid heated by the heating mechanism, the temperature is set to 25 ° C. Thus, when the viscosity is maintained at around 800 cp, a predetermined amount of wet liquid can be applied to the recording head. Needless to say, the temperature at which the heating mechanism is heated is not limited to this temperature, and it is preferable to set a temperature suitable for each.

  Here, as an example of the waiting time in STEP-B9, it is set to 60 seconds. This waiting time is not dependent on this example, and it is preferable to set a suitable time according to the physical properties of the ink and the characteristics of the ink jet printer main body.

  In this way, when wet wiping is performed before printing starts, the temperature of the wet liquid is set to a predetermined temperature, so that a change in viscosity can be eliminated and a necessary amount of wet liquid can be applied to the recording head. As a result, even when pigment ink is used, it is possible to reduce the occurrence of ink sticking and film tension on the face surface of the recording head, and always perform high-quality printing. Furthermore, power consumption can be saved by starting from the start of printing rather than heating and keeping wet liquid from turning on the power.

  A third embodiment of the characteristic configuration of the present invention will be described.

  In the third embodiment, the following control operation is performed in an inkjet recording apparatus capable of wet wiping. If the wet liquid is always warmed up, power will continue to be consumed. Therefore, the wet liquid is heated only during printing.

  The second embodiment will be described with reference to the flowchart of FIG.

  When the printing command is issued, first, in STEP-C1, the environmental temperature Tw is measured by the temperature detection member 36 in FIG. Next, in STEP-C2, it is determined whether the environmental temperature Tw is higher than the threshold temperature Th. If the environmental temperature Tw is higher than the threshold temperature Th, the process proceeds to STEP-C4. On the other hand, when the environmental temperature Tw is lower than the threshold temperature Th, the process proceeds to STEP-C3, the wet liquid is heated by the heating mechanism of FIG. 4, is raised to a predetermined temperature, is kept warm, and the process proceeds to STEP-C4. Next, in STEP-C4, it is determined whether suction recovery is necessary. If suction recovery is not necessary, proceed to STEP-C6. If suction recovery is necessary, proceed to STEP-C5, perform suction recovery, and proceed to STEP-C6. Next, wet wiping is performed in STEP-C6, and printing is performed in STEP-C7. Next, proceeding to STEP-C8, it is determined whether print data has been received. If print data is not received, the process proceeds to STEP-C9. If print data is received, the process proceeds to STEP-C7 to perform printing. Next, in STEP-C9, it is determined whether a predetermined time has been waited. If the predetermined time has not elapsed, the process proceeds to STEP-C8, and the standby is continued. If the predetermined time has elapsed, the process proceeds to STEP-C10. In STEP-C10, wet wiping is performed to remove ink adhering to the recording head. Next, in STEP-C11, the heat retention of the wet wiping solution is completed, and in STEP-C12, capping is performed, and the process waits until the next print data comes.

  Here, as an example of the predetermined temperature of the wet liquid heated by the heating mechanism, the temperature is set to 25 ° C. Thus, when the viscosity is maintained at around 800 cp, a predetermined amount of wet liquid can be applied to the recording head. Needless to say, the temperature at which the heating mechanism is heated is not limited to this temperature, and it is preferable to set a temperature suitable for each.

  Here, as an example of the waiting time in STEP-C9, it is set to 60 seconds. This waiting time is not dependent on this example, and it is preferable to set a suitable time according to the physical properties of the ink and the characteristics of the ink jet printer main body.

  In this way, when performing wet wiping before starting printing, the temperature of the wet liquid is set to a predetermined temperature, thereby eliminating the change in viscosity and transferring the necessary amount of wet liquid to the recording head. Thus, even when pigment ink is used, the occurrence of ink sticking and film tension can be reduced, and high-quality printing can always be performed. Furthermore, power consumption can be further saved by heating and keeping the wet liquid only when print data is received.

  Further, in the above, the recording head can be a head that performs recording by discharging ink, and the head further has thermal energy that causes film boiling in the ink as energy used for discharging the ink. It is possible to have a heat generating element that generates.

  In this specification, “record” is not only formed when significant information such as characters and figures is formed, but also manifested so that human beings can perceive it visually. Regardless of whether or not the image, pattern, pattern or the like is widely formed on the recording medium, or the medium is processed.

  Here, the “recording medium” refers not only to paper used in a general printing apparatus, but also widely to materials that can accept ink, such as cloth, plastic film, metal plate, and the like.

  Further, the term “ink” should be interpreted broadly in the same way as the definition of “recording”. When applied to a recording medium, it is used for forming an image, pattern, pattern, etc. or processing the recording medium. Say liquid to get.

  Although the timing of entering the wet wiping operation of the present invention has not been described, the discharge port surface is dry when the cap open state of the recording head continues for a predetermined time as has been conventionally done. This is because there is a possibility that the so-called timer wiping timing is entered, or when the discharge dot count is recorded and the recording exceeds a predetermined amount, the discharge port surface may be stained with ink mist. It is preferable to perform the wet wiping of the present invention at the timing when so-called dot count wiping is performed.

  Alternatively, the conventional wet wiping is also performed at the timing before closing the cap in order to remove the ink adhering to the ejection port surface of the recording head before closing the cap and prepare for leaving it after that. It is preferable to carry out.

  In addition, since a relatively large amount of ink remaining on the discharge port surface is adhered to the discharge port surface even after a long period of time and after the suction recovery operation performed when the fixed / thickened ink is present in the discharge port of the recording head, In order to remove the remaining ink, it is preferable to perform the wet wiping of the present invention at the timing after the suction.

  In addition, as disclosed in Japanese Patent Laid-Open No. 10-138503, a mechanism for performing wet wiping by heating a processing liquid (coating liquid) has been proposed. In order to perform wet wiping, the temperature of the coating liquid of the present invention is kept constant, so that the temperature of the wet liquid is set to a predetermined temperature at the start of printing. The design philosophy is different from the configuration in which the viscosity change is eliminated and a necessary amount of wet liquid can be applied to the recording head.

1 is a schematic perspective view showing a schematic configuration of an ink jet recording apparatus to which the present invention is applied. It is a schematic front view of a head recovery device for explaining a conventional recovery operation of the ink jet recording apparatus. In the head recovery device shown in FIG. 1, the cleaning operation of the cleaning means is performed in an uncapped state in which at least one of the pigment ink head and the dye ink head is opposed to at least one of the cap for the pigment ink head and the cap for the dye ink head. It is a typical side view shown. FIG. 4 is a schematic diagram for explaining a wet wiping operation by adding a wet wiping configuration to FIG. 3. 3 is a flowchart showing a print alignment sequence according to the first embodiment of the present invention. 6 is a flowchart illustrating a print alignment sequence according to a second embodiment of the present invention. 10 is a flowchart showing a print alignment sequence according to a third embodiment of the present invention. It is a graph which shows the relationship between temperature and the viscosity of glycerol.

Explanation of symbols

1A mat Bk ink head 1B color ink head 2 main scanning carriage 3 main scanning rail 4A cap for mat Bk ink head (capping means)
4B Color ink head cap (capping means)
5A, 5B Suction means (suction pump)
9A, 9B Ink absorbing member 10A Cleaning member (cleaning means) for mat Bk ink head
10B Color ink head cleaning member (cleaning means)
11A, 11B Cleaner 1Aa, 1Ba Discharge port (discharge port)
1a, 1b Discharge port (discharge port)
20 Wet liquid (coating liquid) holding part 21 Transmission member 21a Wiper contact part 22 Heating mechanism 30 Recording material (recording paper, etc.)
31 Paper Feeding Roller 32 Paper Feeding Roller 35 Head Recovery Device 36 Temperature Detection Member

Claims (4)

  In an ink jet recording apparatus that performs recording using a recording head that performs recording by discharging ink onto a recording medium, a cleaning member for wiping off dirt adhering to the recording head, and a coating liquid for cleaning the recording head; A mechanism for holding the coating liquid in the previous period, a mechanism for bringing the cleaning liquid and the coating liquid transmission member in the coating liquid holding means into contact with each other, and transferring the coating liquid to the cleaning member; Temperature measuring means for measuring the temperature of the coating liquid or in the vicinity of the coating liquid, judgment means for determining whether the heating of the coating liquid is necessary by the temperature measuring means, and heating for heating the coating liquid An ink jet recording apparatus comprising: means and heat retaining means for retaining the temperature at a predetermined temperature.   2. The ink jet recording apparatus according to claim 1, wherein the heating means is in the vicinity of an equidistant portion between the cleaning member and the coating liquid holding means.   2. The ink jet recording apparatus according to claim 1, wherein the coating liquid is kept warm while the power is on.   2. The ink jet recording apparatus according to claim 1, wherein the coating liquid is heated only at a predetermined timing during power ON.

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