JP2008254295A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recorder capable of controlling an amount of treatment liquid to be transferred to a wiper for wiping an ejection face of a recording head in accordance with change of ambient temperature, and maintaining good recording quality by the above controlling of the amount of the treatment liquid to be transferred to the wiper even when the treatment liquid is used under low ambient temperature. <P>SOLUTION: This inkjet recorder comprises the recording head for performing the recording by ejecting ink, the wiper made of an elastic member for wiping the ejection face of the recording head, and a treatment liquid supply section for holding the treatment liquid for protecting the ejection face so as to transfer the treatment liquid. By bringing the wiper into contact with the treatment liquid supply section, the treatment liquid is transferred to the wiper. The ejection face is wiped by means of the wiper having the treatment liquid transferred thereto. A free length of the wiper at a time when the wiper is in contact with the treatment liquid supply section, is controlled according to the ambient temperature detected by a temperature detection means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording material, and more particularly to an ink jet recording apparatus that includes a wiper for wiping the discharge surface of the recording head.

  Recording devices such as printers, copiers, and facsimiles are configured to record an image on a recording material by a recording head based on image information, and are used as a single recording device or an output device of a computer or a workstation. Has been. There are various recording systems such as an inkjet system, a laser beam system, and a thermal system. The scanning method includes a serial type in which main scanning in the direction intersecting the conveyance direction of the recording material and sub scanning in the conveyance direction are alternately repeated, and a line type in which recording is performed only in the sub scanning. As the recording material, there are various materials such as photographic printing paper, plastic sheet, OHP sheet, cloth, leather, metal, etc. in addition to ordinary recording paper.

  2. Description of the Related Art An ink jet recording apparatus (ink jet recording apparatus) is configured to perform recording by discharging ink from a discharge port of a recording head to a recording material based on image information. As an energy generating element used for ejecting ink, an element using an electromechanical converter such as a piezo element or an element that heats ink by an electrothermal converting means such as a heating resistor or laser beam irradiation is used. is there.

  In an ink jet recording apparatus, an ejection port array composed of a plurality of ejection ports is formed on the ejection surface of a recording head, and in the case of color recording, a plurality of ejection port arrays for each color are formed in parallel. Yes. In addition, in an inkjet recording apparatus, foreign matters such as ink droplets and paper dust may adhere to the ejection surface of the recording head due to a recording operation, and the ejection surface is wiped with a wiper to remove them. Yes. As the wiper, an elastic member such as a rubber blade is usually used. In some cases, a wiping member made of a porous material may be used.

  Conventionally, inks used in ink jet recording apparatuses have been mainly water-based dye inks. However, dye inks may have insufficient weather resistance due to small dye molecules in the first place. Tends to change over time. In recent years, therefore, water-based pigment inks have been put into practical use instead of water-based dye inks. The pigment ink currently used has a pigment particle size of about 100 nm, which is much larger than the particle size (dye molecule) of the dye. For this reason, the fading of the coloring material is not remarkable even under the influence of light and ozone, and the weather resistance is superior to the dye ink.

  On the other hand, in the ink jet recording apparatus, the discharge ports are becoming finer and higher in density, and clogging due to ink thickening or sticking, clogging due to bubbles or dust, etc. occurs in the fine discharge ports. It has become easier. In color recording using a plurality of colors of ink, it is also necessary to prevent color mixing in which different color inks are mixed inside and outside the ejection port. Therefore, the ink jet recording apparatus is provided with a recovery unit for maintaining and recovering the ink ejection performance of the recording head and preventing the deterioration of the image quality of the recorded image. This recovery unit is usually provided with a cap that covers the ejection port of the recording head and a wiper for wiping off foreign matter adhering to the ejection surface. A pump connected to the cap is also provided. That is, it is configured to perform suction recovery by generating negative pressure with a pump while the discharge port is sealed with a cap, and sucking ink from the discharge port. Preliminary ejection is also performed in which ink not intended for recording is ejected from the recording head to a cap or other ink receiver.

  In an ink jet recording apparatus that performs such a recovery process, when using dye ink, in general, there is not much inconvenience regarding the recording performance and durability of the apparatus. However, when pigment ink is used, the elapsed time until the ink is thickened or fixed is shorter than when dye ink is used, and the viscosity is increased or fixed early. Further, since the wiping property when wiping with a wiper is inferior to that of the dye ink, even if the recording head is wiped depending on the type of pigment, the ink is deposited in a thin film on the ejection surface. Further, the deposited ink is fixed, and it is difficult to sufficiently recover the ejection performance in the operation of wiping with the wiper.

  In a normal dye ink, dye molecules themselves are dissolved in an aqueous solution, but in a pigment ink, since pigment particles are generally hydrophobic, they are not dissolved in water. Therefore, the pigment particles are dispersed in an aqueous solution as a pigment dispersion by adsorbing a resin, an activator, or the like to the pigment particles or adding a solubilizing group. Alternatively, it is 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, when the pigment ink is ejected from the recording head, the ejection surface is more easily wetted with the pigment ink than the dye ink. In a so-called resin-dispersed pigment ink in which a pigment is dispersed using a resin, the ejection surface is more easily wetted by the resin together with the pigment. When wiping is performed in a state where the pigment particles are present on the discharge surface, the discharge surface is easily damaged (scraped or the like), and this also makes the discharge surface easily wet. If the ejection surface becomes wet due to such factors, the ink ejection direction becomes unstable, the ink landing accuracy on the recording surface is lowered, and the image quality is liable to deteriorate.

  For the above inconvenience, it is conceivable to apply a water repellent treatment to repel pigment ink on the ejection surface. However, in the case of an ink that is easily wetted, such as a normal pigment ink, the water repellency gradually deteriorates, and thus the above inconvenience cannot be solved. In addition, wiping spreads the pigment ink that is easily wetted on the discharge surface, resulting in deterioration of water repellency. With respect to such a change in water repellency or hydrophilic performance of the ejection surface, Patent Document 1 discloses a so-called wet wiping technique. In this method, for example, the discharge surface is wiped with a wiper to which a low-volatile solvent (hereinafter, referred to as a treatment liquid or a wet liquid) such as glycerin or polyethylene glycol is attached. By such wiping (referred to as wet wiping), deterioration of water repellency on the ejection surface is prevented.

Moreover, the following three points can be mentioned as an effect | action of said process liquid. The first function is to dissolve the thickened ink and the fixed film accumulated on the ejection surface. The second is an action as a lubricant by being interposed between the wiper and the discharge surface. The third function is to form a protective film on the ejection surface by attaching the treatment liquid to the ejection surface.
JP-A-10-138502

  However, the conventional wet wiping has the disadvantage that the above-described action and its effects are reduced when the environmental temperature is low, and the state of the ejection surface changes or deteriorates compared to the initial state. For this reason, there is a disadvantage that the landing accuracy of the ink droplets ejected from the recording head is lowered and the image quality of the recorded image is lowered. The cause is that the amount of the processing liquid transferred to the wiper varies greatly depending on the environmental temperature. In addition, the treatment liquid should be maintained over the life of the recording apparatus in the first place, and is required to have a property that is difficult to evaporate. Therefore, in consideration of the solubility of the thickened ink and the liquid contact property with the inside of the recording head, the treatment liquid is preferably a polyhydric alcohol such as glycerin or polyethylene glycol which is also used as an ink composition. However, even when such a treatment liquid is used, the conventional wet wiping method cannot exhibit the above-mentioned initial effects, causes a change in the state of the ejection surface, and cannot maintain good ink ejection performance. there were.

  The present invention has been made in view of such technical problems. An object of the present invention is to provide an ink jet recording apparatus capable of controlling the amount of treatment liquid transferred to a wiper for wiping the ejection surface of a recording head in accordance with a change in environmental temperature. Another object of the present invention is to provide an ink jet recording apparatus that can maintain a good recording quality even when a processing liquid is used in a low temperature environment by controlling the transfer amount of the processing liquid to the wiper.

  The present invention relates to a recording head that performs recording by discharging ink from an ejection port disposed on an ejection surface, a wiper that includes an elastic member that wipes the ejection surface of the recording head, and a process for protecting the ejection surface A treatment liquid supply section that holds the liquid, and the wiper contacts the treatment liquid supply section so that the treatment liquid is transferred to the wiper, and the discharge surface is wiped with the wiper to which the treatment liquid is transferred. The inkjet recording apparatus includes a temperature detection unit that detects an environmental temperature, and controls a free length of the wiper when the wiper contacts the processing liquid supply unit according to the detected environmental temperature. And

  According to the present invention, there is provided an ink jet recording apparatus capable of controlling the transfer amount of a processing liquid to a wiper for wiping the discharge surface of a recording head in accordance with a change in environmental temperature. In addition, according to the present invention, there is provided an ink jet recording apparatus capable of maintaining good recording quality even when using a processing liquid in a low temperature environment by controlling the transfer amount of the processing liquid to the wiper.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 1 is a perspective view showing a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. In FIG. 1, a recording material 30 such as recording paper is fed from a front side of the apparatus by a paper feed roller 31 and is U-turned on the back side of the apparatus by a transport mechanism, and then a transport roller 32 and a pinch roller (pressed by this) (Not shown) through the image forming unit. In this image forming unit, the recording head 1 performs recording on the recording material 30. The image forming unit is provided with a carriage 2 that is mounted with a recording head 1 and can reciprocate in the width direction of the recording material. The recording head 1 includes two heads, a black head 1A that performs recording with black ink and a color head 1B that performs recording with color ink. The recording heads 1A and 1B are ink jet recording heads that perform recording by ejecting ink from ejection ports based on image information.

  The carriage 2 is guided and supported so as to be movable along two parallel guide shafts 3 and 3 and is driven by a carriage motor (not shown) via a timing belt (not shown). The recording heads 1 </ b> A and 1 </ b> B are provided with ejection surfaces on which ejection port arrays for each ink color including a plurality of ejection ports are formed. A black discharge port array is formed on the discharge surface of the black recording head 1A, and discharge port arrays of, for example, black, cyan, magenta, and yellow are formed on the discharge surface of the color recording head 1B. . Further, the recording material 30 at the recording position is supported by a platen (not shown), and floating from the platen is restricted by a paper pressing plate 33. In addition, a predetermined gap is provided between the ejection surface of the recording head 1 and the recording surface of the recording material 30 for causing ink droplets to fly. A plurality of ejection port arrays for ejecting each color ink are arranged on the ejection surface of the recording head 1, and each ejection port array is composed of a plurality of ejection ports.

  Therefore, a desired image is formed (recorded) on the recording material 30 by ejecting ink from the ejection port based on the image information in synchronization with the movement (main scanning) of the carriage 2 on which the recording head is mounted. . Recording of the entire recording material is performed by alternately repeating the recording for one line by the movement of the carriage and the paper feeding at a predetermined pitch. The recorded recording material is conveyed while being sandwiched between a paper discharge roller and a spur (not shown), and discharged from the front of the apparatus.

  A recovery unit 35 for maintaining and recovering the ink ejection performance of the recording head 1 is disposed at a position HP that is within the moving range of the carriage 2 (usually the home position of the recording head 1) HP. Further, in the vicinity of the recovery unit 35, a temperature detecting means including a temperature sensor 36 for detecting the environmental temperature is arranged. As the temperature sensor 36, for example, a thermistor is used.

(First embodiment)
FIG. 2 is a partially broken front view showing a state when the recording head is wiped in the recovery unit of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 3 is a longitudinal sectional view showing the state when the recording head is wiped in the recovery unit of FIG. 2 together with the movement of the wiping means. FIG. 4 is a partially broken perspective view when the wiping means in FIG. 3 reaches the processing liquid supply unit. FIG. 5 is a longitudinal sectional view when the wiping means in a normal use form contacts the processing liquid supply unit. FIG. 6 is a longitudinal sectional view when the wiping means having a reduced free length of the wiper comes into contact with the processing liquid supply unit.

  2 and 3, a recording head 1 including a black head 1 </ b> A and a color head 1 </ b> B is mounted on a carriage 2 that can move along a guide shaft 3. As the recording heads 1 </ b> A and 1 </ b> B, for example, those including an electrothermal converter for generating thermal energy for ejecting ink are used. The recording head 1 causes film boiling in the ink in the ejection port by the heat energy applied by the electrothermal transducer, and ejects ink from the ejection port by utilizing the pressure change caused by the growth and contraction of bubbles generated at that time. It is something to be made.

  The recovery unit 35 is provided with caps 4A and 4B that can seal the discharge ports (or discharge port arrays) 1Aa and 1Ba by being in close contact with the discharge surfaces of the black head 1A and the color head 1B. The caps 4A and 4B are formed of rubber-like elastic members. The caps 4A and 4B are connected to the suction pumps 5A and 5B via the tubes 6A and 6B. The suction pumps 5A and 5B are connected to the waste ink tank 8 via the tubes 7A and 7B. By operating the suction pump with the discharge port sealed with the cap, a negative pressure is generated in the cap, and the negative pressure can suck out thickened ink, bubbles, and the like from the discharge port together with the ink. By such suction, suction recovery is performed to refresh the ink in the ejection port.

  Further, the recovery unit 35 is provided with wiping means 100 having wipers 10A and 10B for wiping the ejection surfaces of the recording heads 1A and 1B. The wipers 10A and 10B are formed of a plate-like elastic member such as a rubber-like elastic body. The wiping means 100 is movable in a direction intersecting with the movement direction of the carriage 2. That is, the wiping means 100 is movable through the positions indicated by (1) to (5) in FIG. At that time, when moving from (1) to (3), the wiper 10A, 10B is rubbed against the discharge surface to wipe off foreign matters such as ink and paper dust attached to the discharge surface. Yes.

  FIG. 2 shows a state where wiping by the wiping means 100 is possible with the cap being separated from the ejection surface of the recording head. At this time, the black cap 4A is separated from the ejection surface on which the ejection port of the black head 1A is formed, and the color cap 4B is also separated from the ejection surface on which the ejection port of the color head 1B is formed. On the other hand, in the capping state in which the caps 4A and 4B are brought into close contact with the ejection surfaces of the recording heads 1A and 1B and the ejection ports are sealed, the ejection surface can be protected and ink evaporation from the ejection ports can be suppressed. When there is a recording signal, the recording head 1 descends in the direction of arrow C to enter the cap open state as shown in FIGS. 2 and 3, and a recording operation is possible. FIG. 3 shows the operation positions (1) to (5) when the wipers 10A and 10B wipe the ejection surface in the cap open state.

  Inside the caps 4A and 4B, ink absorbers 9A and 9B made of a porous or sponge-like material are loaded. As one of the recovery operations of the recording head 1, there is a case where preliminary ejection for ejecting ink not intended for recording is performed. This preliminary discharge is mainly intended to discharge the mixed color ink and the thickened ink in the discharge port, and is usually performed at a predetermined cycle. Such preliminary ejection is performed by ejecting ink to a cap or other ink receiver in a cap open state.

  In suction recovery, the suction pumps 5A and 5B are operated in a capping state in which the discharge ports are sealed with caps, and negative suction pressure is applied to the discharge ports 1Aa and 1Ba of the heads 1A and 1B. Ink is forcibly sucked from the ejection port. The sucked ink is discharged to the waste ink tank 8 through the tubes 7A and 7B. This suction recovery can be appropriately executed as necessary, such as during recording standby or during a recording operation.

  The wipers 10A and 10B are formed of a plate-like (or blade-like) elastic member made of a rubber-like elastic material such as urethane, butyl, or silicon. The wiper can also be formed of a porous member or a sponge member. In FIG. 3, each wiper 10 </ b> A, 10 </ b> B is movable in the directions of arrows D and E by a drive source (not shown). The discharge surface including the discharge ports 1Aa and 1Ba is wiped by the movement in the direction of arrow D (operation (1) → (2) → (3) in FIG. 3). And if it moves to the direction of arrow D further after wiping, it will contact | abut to wiper cleaners 11A and 11B (position (4) in FIG. 3). By contacting the wiper cleaners 11A and 11B, a cleaning operation for transferring (transferring) ink and dust adhering to the wipers 10A and 10B is performed. At this time, the caps 4A, 4B are moved in the direction of arrow C by a drive source (not shown), and are retracted to a position where they do not interfere with the wipers 10A, 10B.

  2 to 6, a wiper return position 22 is set at a position further advanced in the direction of arrow D from the wiper cleaners 11A and 11B. A treatment liquid supply unit 50 used for wet wiping is disposed immediately before the wiper folding position 22. FIG. 4 shows a state when the wiping means 100 reaches the processing liquid supply unit 50. The ink jet recording apparatus according to the present embodiment has a configuration for wet wiping. In this wet wiping, the treatment liquid is transferred (or applied) to the wiping surfaces (surfaces that slide on the discharge surfaces) of the wipers 10A and 10B, and the discharge surfaces are wiped with a wiper to which the treatment liquid is transferred. A treatment operation for attaching a treatment liquid to a surface. The treatment liquid protects the ejection surface, such as protecting the surface treatment such as water repellency treatment on the ejection surface of the recording head, and preventing damage when peeling the fixed film or thickener deposited on the ejection surface. It is liquid.

  As the treatment liquid (wet liquid), for example, a single solvent or a mixed solvent of polyhydric alcohols such as ethylene glycol, diethylene glycol, glycerin, and polyethylene glycol is used. A treatment liquid (wet liquid) used for wet wiping is generally a solvent having low volatility and a liquid whose viscosity increases in a low temperature environment. FIG. 11 is a graph illustrating the viscosity change with respect to the temperature of glycerin used as the treatment liquid. By this wet wiping, it is possible to prevent deterioration of the water-repellent or hydrophilic treatment film on the ejection surface. The action of the treatment liquid in this case includes the action of dissolving the thickened ink and the fixed film accumulated on the ejection surface, the action as a lubricant by being interposed between the wiper and the ejection surface, and the treatment on the ejection surface. There is an effect of forming a protective film on the discharge surface by adhering the liquid.

  Next, the structure of the wiping means 100 in this embodiment is demonstrated. The wiping means 100 has a configuration in which wipers 10A and 10B and a wiper support member 103 are mounted on a slidable wiper holder 101. The wiper support member 103 is attached so as to be rotatable about a rotation axis 104 within a range of about 90 degrees between a horizontal position and a vertical position. The wiper support member 103 is disposed so as to contact the upstream surface of the wipers 10A and 10B in the wiping direction. The rotational position of the wiper support member 103 is mechanically changed to change the contact length between the wiper support member and the wipers 10A and 10B, thereby changing the free length of the wiper. Has been.

  Here, the free length of the wiper is a length in a range that can be elastically deformed when sliding on the discharge surface, and indicates the length of the V portion of the wiper in FIGS. 5 and 6. That is, the wiper support means 100 shortens the free length V (FIGS. 5 and 6) of the wiper by moving the contact position of the wiper support member 103 with respect to the wipers 10A and 10B toward the free end of the wiper. It is configured as follows. Further, the rotational position of the wiper support member 103 (and hence the free length V of the wiper) is controlled in accordance with the detection result of the environmental temperature of the temperature detection means 36 comprising a thermistor or the like provided in the recording apparatus. The processing liquid supply unit 50 is disposed immediately before the folding position 22 of the wiping means 100. In the wet wiping in this embodiment, the discharge surface is transferred by the wipers 10A and 10B to which the processing liquid is transferred by the processing liquid supply unit 50. This is performed by the wiping operation. The free length of the wipers 10a and 10B is controlled by controlling the position of the wiper support member 103 that contacts the surface of the wiper that is opposite to the surface that contacts the processing liquid supply unit 50 (the processing liquid transfer unit 21). Done.

  The processing liquid supply unit 50 holds a processing liquid for protecting the ejection surface of the recording head 1. The processing liquid supply unit 50 of the present embodiment has a structure in which the processing liquid holding unit 20 and the processing liquid transfer unit 21 are joined. The processing liquid holding unit 20 is a part that stores and holds the processing liquid. The processing liquid transfer unit 21 is a part that transfers the processing liquid that has permeated (transmitted) from the processing liquid holding unit 20 to the wiper when the wipers 10A and 10B come into contact with each other. The treatment liquid holding part 20 and the treatment liquid transfer part 21 constituting the treatment liquid supply part 50 are formed of a treatment liquid absorber made of fibers or a foam with a continuous foam, for example, a polypropylene fiber in a sponge shape. It is formed of things (also called PP sponge). Note that the processing liquid holding unit 20 and the processing liquid transfer unit 21 may be formed of the same material. However, in order to reliably supply (permeate) the processing liquid from the processing liquid holding unit 20 to the processing liquid transfer unit 21, it is necessary to make the capillary force of the processing liquid transfer unit 21 stronger than the capillary force of the processing liquid holding unit 20. There is. Therefore, the average pore diameter, the apparent density, the capillary force, and the like of the treatment liquid holding part and the treatment liquid transfer part are selected so as to maintain such a strong and weak relationship of the capillary force.

  While the wiping means 100 moves from the left side to the right side in FIG. 3, the wipers 10A and 10B wipe the ejection surfaces of the recording heads 1A and 1B. Next, the wiper is cleaned (cleaned) by the wiper cleaners 11A and 11B, and then reaches the processing liquid supply unit 50 (operation (4) → (5)). That is, the wipers 10A and 10B that have moved come into contact with the processing liquid transfer portion 21 before the turn-back position 22 as shown in the processing liquid transfer position (5) in FIG. Then, while the wipers 10 </ b> A and 10 </ b> B are in contact with the processing liquid transfer unit 21, the processing liquid is transferred from the processing liquid transfer unit to the wiper. At this time, the wiper and the treatment liquid transfer unit may be brought into contact in a stopped state or in contact with each other while being moved.

  The wiper (wiping means 100) to which the processing liquid has been transferred returns to the processing liquid transfer position (5) → the initial position (1) and stops at the initial standby position (1). At this time, the wiper cleaners 11 </ b> A and 11 </ b> B are retracted to positions where they do not interfere with the wiping means 100. Further, the carriage 2 is also moved to a position deviated from the wiping position, and the recording head is not wiped by the rear surfaces of the wipers 10A and 10B. Thus, the wiping means 100 returns to the initial stop position (1) by sequentially moving as indicated by the positions (5) → (3) → (1) in FIG.

  According to the wet wiping having the above configuration, at the time of the first wiping by the wipers 10A and 10B, the recording head is wiped by the wiper to which the processing liquid is not transferred. That is, the next wiping (wiping performed while attaching the processing liquid to the ejection surface) is performed using the processing liquid transferred to the wiper at the time of the first wiping. The same applies to the second and subsequent times. In this case, since the processing liquid is a liquid that is harder to evaporate than ink or the like, it does not evaporate and disappear at the next wiping. Further, since the treatment liquid has a viscosity much higher than that of normal ink, it does not flow out after adhering to the wiper. Further, the change in the state of the ejection surface due to the first dry wiping (wiping without using the treatment liquid) for the first time is also slightly smaller than the wiping durability count in the recording apparatus and can be ignored.

  In the above embodiment, the wiping means 100 that reciprocally moves has been described as an example. However, the above wet wiping is a rotary type in which the tip of a blade that rotates about a support shaft is rubbed against the discharge surface. The same applies to the wiping means. Further, the present invention can be similarly applied to reciprocating wipers having other configurations such as different moving directions with respect to the recording head. Further, in the slide type wiping means as described above, a configuration is provided in which a second folding position is provided between the position (4) and the position (5) in FIG. 3 and the initial stop position (1) is returned therefrom. You may take it. According to this configuration, it is possible to select wet wiping including a process liquid transfer process and wiping not including a process liquid transfer process.

  Next, the retention and transfer (transmission) of the processing liquid, the state of the ejection surface of the recording head, the ink used, and the like will be further described. 3 and 4, the processing liquid in the processing liquid holding unit 20 is impregnated and held by impregnating PP sponge or the like made of a polypropylene fiber into a sponge shape. In this case, 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 are appropriately selected. Further, in order to ensure the movement of the processing liquid in the processing liquid supply unit 50, it is necessary to make the capillary force of the transfer unit 21 stronger than the capillary force of the holding unit 20, and maintain such a relationship. The average pore diameter, apparent density, capillary force, etc. of each part are selected.

  In this embodiment, glycerin is used as the processing liquid. This glycerin easily absorbs moisture in the air, and even when it has once absorbed moisture, it has a characteristic of releasing moisture and drying in a low humidity environment. For this reason, it is preferable to shield the outer periphery of the treatment liquid holding unit 20 and the treatment liquid transfer unit 21 with a material having low water vapor permeability so as not to be affected by moisture absorption or drying. However, it is preferable not to be completely sealed but to provide a part of air communication pores so as to withstand expansion and contraction of air existing in the treatment liquid holding part. Further, a solvent such as glycerin that is preferably used as a treatment liquid has a property that the viscosity is greatly increased when the environmental temperature is lowered as illustrated in FIG.

  As the black ink used in the recording head 1A, a self-dispersing pigment ink is used. This is an ink in which pigment particles are self-dispersed in an aqueous solution by imparting hydrophilic groups to the ends of the structure of the pigment particles. On the other hand, color pigment ink is used as the color ink (black, cyan, magenta, yellow) used in the recording head 1B. These are inks in which pigment particles are dispersed in water with a resin having a surfactant action.

  The volume of the processing liquid holding unit 20 calculated backward from the required amount of processing liquid is calculated as follows. First, even if wet wiping equivalent to the durable number of sheets of the recording device is performed, there is no significant change in the water-repellent state of the ejection surface, and the processing liquid required to maintain the ejection ink landing accuracy within an allowable range. The amount of transcription is determined by experiment. From this required transfer amount, a volume capable of containing and holding an amount of processing liquid multiplied by the number of wipings corresponding to the durable number is calculated and set to that volume. For example, the water repellent discharge surface is wiped with a wiper to which 1 mg of glycerin has been transferred. When the target durable number of 10,000 sheets can be recorded without any problem, the amount of glycerin required for the durable number of 10,000 sheets is 10 g in calculation.

  Based on the necessary amount in this calculation, considering the density of glycerin, the amount of glycerin retained in the treatment liquid holding unit 20 and the treatment liquid transfer unit 21, the remaining amount when the glycerin is used up, etc. A volume of about 20 cc is required. Although the initial glycerin injection amount depends on the exhaustion efficiency, it is normally not possible to expect 100% use up, so it is necessary to inject about 1.2 times the required amount. These conditions, that is, the amount of glycerin necessary for one wiping, the number of durable sheets, and the amount of glycerin retained in the PP sponge and the processing liquid transfer unit (transmission member) 21 vary depending on the conditions for each recording apparatus. Accordingly, these are appropriately set for each recording apparatus.

  The present embodiment is not limited to the use conditions as described above. The material and amount of the processing liquid, or the processing liquid holding unit 20 and the processing liquid transfer unit 21 material and size are as follows. It is selected and implemented as appropriate in consideration of the actual usage. Further, the water-repellent, non-water-repellent or hydrophilic state of the discharge surface can be changed as appropriate. Also, the surface tension, which is an index of ink wettability, the contact angle of the ink with respect to the ejection surface, and the like can be changed as appropriate, and can be implemented in various forms. Further, regarding the ink itself, the case where the pigment ink is used is illustrated in the present embodiment, but the present invention can be similarly applied to the case where the dye ink is used only by changing a part of the conditions.

  Next, the control of the transfer amount to the wiper in consideration of the increase in the viscosity of the treatment liquid when the environmental temperature is lowered will be specifically described. 3 to 6, the rotational position of the wiper support member 103 is driven and controlled according to the detected temperature of the temperature detecting means 36 formed of a thermistor or the like. By mechanically changing the rotational position of the wiper support member 103, the contact length with the wipers 10A and 10B can be changed. Thereby, the length of the range V which can be elastically deformed when the wiper is wiped can be controlled. By changing the free length of the wiper, it is possible to change the wiping pressure of the wiper with respect to the processing liquid transfer unit 21, thereby adjusting the transfer amount of the processing liquid. In other words, when the free length is shortened, the wiper has a higher rigidity and the wiping pressure becomes stronger. If the viscosity of the treatment liquid is the same, the transfer amount can be increased.

  5 and 6 show a state where the wiper 10 comes into contact with the processing liquid transfer unit 21 of the processing liquid supply unit 50 in wet wiping, and FIG. 5 shows a normal usage pattern of the free length V of the wiper. FIG. 6 shows a case where the free length V of the wiper is shortened. In the present embodiment, the free length V of the wipers 10A and 10B is selected to be 0.8 mm in the normal usage mode of FIG. 5, and is selected to be 0.4 mm in the usage mode when shortened in FIG. . The wiper support member 103 is controlled by a control unit and a drive unit (not shown) so as to rotate about 90 degrees around the rotation shaft 104 according to the environmental temperature. When the wiper support member 103 is in a horizontal position as shown in FIG. 5, the length of contact with the rear surfaces (surfaces upstream of the wiping direction) of the wipers 10A and 10B is shortened, and the free length V is lengthened. On the other hand, when the wiper support member 103 is in the vertical position as shown in FIG. 6, the length of contact with the rear surfaces of the wipers 10A and 10B is increased, and the free length V is shortened.

The experimental results relating to the free length V of the wiper in the present embodiment are shown in “Table 1” below.

  “Table 1” shows the processing liquid per transfer process at each environmental temperature when the amount of wipers 10A and 10B entering the processing liquid transfer portion 21 is set to 1.0 mm and the free length V is changed. Indicates the transfer amount. When such control of the free length is not performed, the transfer amount of the processing liquid varies greatly depending on the environmental temperature, as shown as (reference) in the right column of Table 1. For example, as shown in Table 1, in a low temperature environment of 5 degrees Celsius, it decreases to 0.3 mg and 1/3 or less with respect to 1.1 mg at room temperature (25 degrees Celsius), and the desired wet wiping The performance cannot be demonstrated. On the other hand, by controlling the free length V of the wiper as in this embodiment, the transfer amount is 1.0 mg even in a low temperature environment of 5 degrees Celsius, which is substantially the same as that at normal temperature. It becomes possible to do.

  Thereafter, the wiping means 100 returns again from the processing liquid transfer position (5) in FIG. 3 to the standby position (1) and stops at this standby position. In the next wiping, the wiper 10A, 10B to which the treatment liquid is transferred wipes the discharge surfaces of the recording heads 1A, 1B, and the treatment liquid adheres to the discharge surfaces so that the state of the discharge surfaces is good. Can be maintained. In this wiping step, it is preferable that the free length V of the wiper be constant regardless of the environmental temperature in view of damage to the discharge surface and wiping properties. In this embodiment, the free length at this time is at room temperature. It was set to 0.8 mm, the same as the usage pattern.

  As described above, in this embodiment, the temperature detection unit 36 detects the environmental temperature, and controls the free length of the wiper according to the environmental temperature, thereby transferring the transfer amount due to the thickening of the processing liquid in a low temperature environment. The decrease of the is corrected. For this reason, the desired wet wiping performance can be sufficiently exhibited regardless of the fluctuation of the environmental temperature. As a result, it is possible to prevent changes in the state of the ejection surface due to wiping during the durability of the recording device, and to maintain the state of the ejection surface properly until the end of the durability of the recording device, thereby reducing the landing accuracy of the ejection ink. The recording quality can be maintained. That is, an ink jet recording apparatus is provided that can control the transfer amount of the processing liquid to the wiper for wiping the ejection surface of the recording head in accordance with changes in the environmental temperature. By controlling the transfer amount of the processing liquid to the wiper, an ink jet recording apparatus that can stably maintain a good recording quality for a long period of time even when used in a low temperature environment is provided.

(Second Embodiment)
FIG. 7 is a longitudinal sectional view showing a state when the recording head is wiped in the recovery unit of the ink jet recording apparatus according to the second embodiment of the present invention, together with the movement of the wiping means. FIG. 8 is a longitudinal sectional view when the wiping means in the normal usage pattern contacts the processing liquid supply unit in the wet wiping according to the second embodiment. FIG. 9 is a longitudinal cross-sectional view when the wiping means in which the free length of the wiper is shortened in the wet wiping according to the second embodiment contacts the processing liquid supply unit. FIG. 10 is a longitudinal cross-sectional view when the wiping means in which the free length of the wiper is extended in the wet wiping according to the second embodiment contacts the processing liquid supply unit.

  7 to 10, also in the wiping means 200 according to the present embodiment, the wipers 10 </ b> A and 10 </ b> B are held by a wiper holder 201 that can move in a direction intersecting the moving direction of the carriage 2. An eccentric cam 205 that can rotate around a rotation shaft 206 is pivotally supported on the wiper holder 201 of this embodiment. A wiper support member 207 and a transmission member 208 are attached to the wiper holder 201 so as to be slidable in the vertical direction. The transmission member 208 is engaged with the eccentric cam 205 so as to move up and down with the rotation of the eccentric cam 205. The lower end surface of the wiper support member 207 is in contact with the upper end surface of the transmission member 208, and the wiper support member 207 similarly moves up and down as the transmission member 208 moves up and down. At that time, the wiper support member 207 moves in the vertical direction in a state where the wiper support member 207 is in contact with the upstream surface (back surface) of the wipers 10A and 10B in the wiping direction.

  Thus, the wiping means 200 changes the contact length between the wiper support member 207 and the wipers 10A and 10B by mechanically changing the rotational position of the eccentric cam 205, thereby reducing the free length W of the wipers 10A and 10B. Configured to control. The free length W of the wiper is a length that can be elastically deformed when rubbed against the ejection surfaces of the recording heads 1A and 1B. The length of the W portion of the wipers 10A and 10B shown in FIGS. Refers to The control of the free length W of the wipers 10A and 10B is performed by controlling the position of the wiper support member 207 that contacts the surface of the wiper that is opposite to the surface that contacts the processing liquid supply unit 50 (the processing liquid transfer unit 21). Is called. The rotational position of the eccentric cam 205 (and hence the free length W of the wipers 10A and 10B) is controlled according to the detected temperature of the temperature detecting means 36 (FIG. 1) comprising a thermistor or the like provided in the recording apparatus. Other configurations of the present embodiment are the same as those of the first embodiment described above.

  Therefore, also in the present embodiment, the amount of treatment liquid transferred can be adjusted by changing the wiper wiping pressure with respect to the treatment liquid transfer unit 21 of the treatment liquid supply unit 50 by changing the free length W of the wiper. . That is, when the free length W is shortened, the wiper's rigidity is increased, so that the wiping pressure is increased, and the transfer amount is increased if the viscosity of the treatment liquid is the same. In the normal usage pattern of the wipers 10A and 10B shown in FIG. 8, the free length W of the wiper is set to 0.8 mm. In the usage form in the low temperature environment shown in FIG. 9, the free length W of the wipers 10A and 10B is set to 0.4 mm. Furthermore, in the usage pattern in which the free length W of the wipers 10A and 10B as shown in FIG. 10 is extended, the length of the free length W is set to 1.0 mm.

  The rotational position of the eccentric cam 205 for adjusting the free length W of the wipers 10A and 10B is appropriately controlled according to the environmental temperature by a control unit and a drive unit (not shown). In other words, in a normal use mode, as shown in FIG. 8, the free length W of the wipers 10A and 10B is set to a normal length (for example, 0.8 mm) by holding the eccentric cam 207 at an intermediate position. When the temperature detection means 36 of the recording apparatus detects that the environmental temperature is low, the eccentric cam 205 is rotated to the position shown in FIG. 9 by the control unit and drive unit (not shown) to raise the wiper support member 207. Thereby, the amount of transcription | transfer when the viscosity of a process liquid is the same can be increased by shortening the free length W of a wiper and improving rigidity. When it is detected that the environmental temperature is high, the eccentric cam 205 is rotated to the position of FIG. 10 by a control unit and a drive unit (not shown), and the wiper support member 207 is lowered. Thereby, the transfer amount when the viscosity of the treatment liquid is the same can be reduced.

The experimental results regarding the free length W of the wiper in the present embodiment are shown in “Table 2” below.

  “Table 2” shows the processing liquid per transfer step at each environmental temperature when the amount of entry of the wipers 10A and 10B into the processing liquid transfer portion 21 is set to 1.0 mm and the free length W is changed. Indicates the transfer amount. When such control of the free length is not performed, the transfer amount of the processing liquid greatly varies depending on the environmental temperature, as shown as (reference) in the right column of Table 2. For example, as shown in Table 2, in a low temperature environment of 5 degrees Celsius, it decreases to 0.3 mg and 1/3 or less with respect to 1.1 mg at room temperature (25 degrees Celsius), and the desired wet wiping The performance cannot be demonstrated. On the other hand, by controlling the free length W of the wiper as in this embodiment, the transfer amount is 1.0 mg even in a low temperature environment of 5 degrees Celsius, which is substantially the same as that at normal temperature. It becomes possible to do.

  Thereafter, the wiping means 100 returns again from the processing liquid transfer position (5) in FIG. 7 to the standby position (1) and stops at this standby position. In the next wiping, the wiper 10A, 10B to which the treatment liquid is transferred wipes the discharge surfaces of the recording heads 1A, 1B, and the treatment liquid adheres to the discharge surfaces so that the state of the discharge surfaces is good. Can be maintained. In this wiping step, it is preferable that the free length W of the wiper be constant regardless of the environmental temperature in view of damage to the discharge surface and wiping properties. In this embodiment, the free length at this time is at room temperature. It was set to 0.8 mm, the same as the usage pattern.

  As described above, also in this embodiment, the temperature detection means 36 detects the environmental temperature and controls the free length of the wiper according to the environmental temperature, thereby transferring the transfer amount due to the thickening of the processing liquid in a low temperature environment. The decrease of the is corrected. Further, in this embodiment, an increase in the transfer amount due to a decrease in the viscosity of the processing solution under a high temperature environment is corrected, thereby preventing unnecessary consumption of the processing solution. Here, the degree of controlling the free length W in a low-temperature environment or a high-temperature environment can be appropriately set according to a predetermined temperature so that a desired wet wiping performance can be exhibited, and more than a necessary amount of processing liquid Can be set not to consume.

  According to the embodiment described above, by controlling the free length of the wiper under various environmental temperatures, it is possible to correct a decrease in transfer amount or an increase beyond necessity due to a change in the viscosity of the processing liquid. For this reason, it is possible to sufficiently exhibit the desired wet wiping performance regardless of fluctuations in the environmental temperature, and it is possible to prevent waste of the processing liquid. As a result, it is possible to prevent changes in the state of the ejection surface due to wiping during the durability of the recording apparatus, and to maintain the ejection surface state properly until the end of the durability of the recording apparatus, thereby reducing the landing accuracy of the ejected ink. The recording quality can be maintained. At the same time, wet wiping can be realized without consuming more processing liquid than necessary.

  That is, an ink jet recording apparatus capable of controlling the transfer amount of the processing liquid to the wiper for wiping the discharge surface of the recording head according to the change in the environmental temperature is provided. Then, by controlling the transfer amount of the processing liquid to the wiper, it is possible to correct the decrease in the processing liquid under the low temperature environment while preventing the waste of the processing liquid under the high temperature environment. This provides an ink jet recording apparatus that can stably maintain good recording quality over a long period of time even in long-term use.

  In the embodiment described above, a serial type recording apparatus using a carriage mounted with a recording head and reciprocally moved is taken as an example. The present invention can be similarly applied to other recording methods such as a line type recording apparatus that records only by sub-scanning in the direction in which the recording material is conveyed. Further, the present invention can be similarly applied to a recording apparatus in a complex apparatus or a system configuration as well as a single recording apparatus such as a printer, a facsimile machine, and a copying machine. Further, regarding the recording material, various materials such as paper, plastic sheet, OHP sheet, cloth, and photographic printing paper can be used as long as image recording is possible.

1 is a perspective view illustrating a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 3 is a partially broken front view showing a state when the recording head is wiped in the recovery unit of the ink jet recording apparatus according to the first embodiment of the present invention. FIG. 3 is a longitudinal sectional view showing a state when the recording head is wiped in the recovery unit of FIG. 2 together with the movement of the wiping means. FIG. 4 is a partially broken perspective view when the wiping means in FIG. 3 reaches a processing liquid supply unit. It is a longitudinal cross-sectional view when the wiping means of the normal usage pattern contacts the process liquid supply part in the wet wiping according to the first embodiment. It is a longitudinal cross-sectional view when the wiping means which shortened the free length of the wiper in wet wiping which concerns on 1st Embodiment contacts a process liquid supply part. FIG. 6 is a longitudinal sectional view showing a state when a recording head is wiped in a recovery unit of an ink jet recording apparatus according to a second embodiment of the present invention, together with the movement of a wiping means. In the wet wiping which concerns on 2nd Embodiment, it is a longitudinal cross-sectional view when the wiping means of a normal usage pattern contacts a process liquid supply part. It is a longitudinal cross-sectional view when the wiping means which shortened the free length of the wiper in wet wiping which concerns on 2nd Embodiment contacts a process liquid supply part. It is a longitudinal cross-sectional view when the wiping means which extended the free length of the wiper in wet wiping which concerns on 2nd Embodiment contacts a process liquid supply part. It is a graph which illustrates the viscosity change with respect to the temperature of glycerol suitable for using as a processing liquid of wet wiping in an inkjet recording device.

Explanation of symbols

1 (1A, 1B) Recording head 10 (10A, 10B) Wiper 20 Treatment liquid holding part 21 Treatment liquid transfer part 35 Recovery unit 36 Temperature detection means 50 Treatment liquid supply part 100, 200 Wiping means 101, 201 Wiper holder 103, 207 Wiper support member V, W Free length of wiper

Claims (7)

A recording head that performs recording by ejecting ink from an ejection port disposed on the ejection surface, a wiper made of an elastic member that wipes the ejection surface of the recording head, and a processing liquid for protecting the ejection surface are held. An inkjet recording apparatus comprising: a treatment liquid supply unit; wherein the wiper contacts the treatment liquid supply unit to transfer the treatment liquid to the wiper, and the wiper to which the treatment liquid is transferred wipes the ejection surface. ,
It has temperature detection means to detect the environmental temperature,
An ink jet recording apparatus, comprising: controlling a free length of the wiper when the wiper contacts the processing liquid supply unit according to the detected environmental temperature.   2. The ink jet recording apparatus according to claim 1, wherein the free length of the wiper is shortened when the environmental temperature is low.   The control of the free length of the wiper is control of a position of a wiper support member that abuts on a surface of the wiper that is opposite to a surface that contacts the treatment liquid supply unit. Inkjet recording apparatus.   4. The ink jet recording apparatus according to claim 3, wherein the free length of the wiper is shortened by moving the contact position of the wiper support member toward the free end of the wiper.   5. The ink jet recording apparatus according to claim 1, wherein the treatment liquid is a single solvent or a mixed solvent of polyhydric alcohols such as ethylene glycol, diethylene glycol, glycerin, and polyethylene glycol.   The ink jet recording apparatus according to claim 1, wherein the processing liquid supply unit is a processing liquid absorber made of fibers or an open-cell foam.   The processing liquid supply unit has a structure in which a processing liquid holding unit that holds processing liquid and a processing liquid transfer unit that contacts the wiper are joined, and the capillary force of the processing liquid transfer unit is The inkjet recording apparatus according to claim 6, wherein the inkjet recording apparatus is stronger than a capillary force.

Images