JP4708933B2 - Inkjet recording apparatus and head recovery method - Google Patents

Description

  The present invention relates to an inkjet recording apparatus and a head recovery method, and in particular, is applied to, for example, a recording apparatus that maintains the performance of a recording head by wiping the ink ejection surface of an inkjet recording head and performs high-quality recording. The present invention relates to a head recovery method.

  The recording apparatus is used as a recording unit of a multifunction machine having functions such as a printer, a copier, and a facsimile machine, or as an output device such as a composite electronic device including a computer or a word processor or a workstation. Such a recording apparatus records an image (including characters and symbols) on a recording medium such as paper, cloth, a plastic sheet, and an OHP sheet based on the recording information. In particular, an ink jet recording apparatus (hereinafter referred to as a recording apparatus) performs recording by discharging ink from an ink jet recording head (hereinafter referred to as a recording head) to a recording medium. This recording apparatus is characterized in that the recording head can be easily downsized, a high-definition image can be recorded at high speed, and recording can be performed on plain paper without requiring special processing. In addition, the running cost is low, the non-impact method is low in noise, and it is easy to record a color image using various types of inks (for example, color inks). .

  As an energy generating element that generates energy used to eject ink from the ejection port of the recording head, an electromechanical converter such as a piezo element, a semiconductor laser that emits electromagnetic waves, or an electrothermal conversion having a heating resistor There is a body (hereinafter referred to as a heater). Among them, a recording head that employs a recording method that uses thermal energy to discharge ink droplets can perform high-resolution recording because the ink 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. The advantages of can be fully utilized. This is advantageous because high-density mounting is easy and the manufacturing cost is low.

  There are various requirements for the material of the recording medium. In recent years, the development of these requirements has progressed, and in addition to normal recording media such as paper (including thin paper and processed paper) and resin thin plates (OHP, etc.), recording media such as cloth, leather, non-woven fabric, and metal are also available. A recording apparatus used as a recording medium is also used.

  The recording apparatus includes a serial type recording apparatus that performs recording while scanning in a direction crossing the conveyance direction of the recording medium, and a recording of a predetermined length that is held at a fixed position so as to cover a range of a predetermined width in the width direction of the recording medium. It can be roughly classified into a line type recording apparatus that performs recording using a head.

  In the recording apparatus, foreign matters such as ink droplets, dust, dust, and paper dust may adhere to the ink discharge surface of the recording head due to the recording operation, and a cleaning mechanism is provided to remove these foreign matters. Yes. The ink discharge surface is cleaned (for example, wiped by rubbing) by the cleaning member of this mechanism. As the cleaning member, a flexible member such as a rubber blade made of a rubber-like elastic material is usually used. Further, the ink near the ink discharge port (hereinafter referred to as nozzle) of the recording head dries, and the nozzle may become clogged due to thickening, fixing, and accumulation of the ink. Further, the nozzle may be clogged by bubbles or dust generated inside the nozzle (liquid passage). In order to recover (prevention, elimination, etc.) from these clogging, for example, the nozzle is sealed using a capping member, and a predetermined negative pressure suction force is generated on the ink ejection surface using a pump. The suction recovery of forcibly discharging is performed. In addition, in order to remove ink adhering to the ink ejection surface due to suction recovery, the ink ejection surface is also cleaned (wiped off) by a cleaning member.

  Conventionally, ink using water-based dye ink (hereinafter referred to as dye ink) has been the mainstream as ink used in recording apparatuses. However, since the dye ink is small in the first place, the so-called weather resistance such as light resistance and gas resistance 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 (hereinafter referred to as pigment inks) have been put into practical use in place of dye inks. Currently used pigment inks have a pigment particle size of approximately 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 is weather resistant. Is much better than dye inks.

  Next, the head recovery operation in the conventional recording apparatus will be described.

  FIG. 8 is a schematic cross-sectional view showing the configuration of a head recovery mechanism that performs a recovery operation of a recording head mounted in a conventional recording apparatus.

  FIG. 9 is a side sectional view of the head recovery mechanism viewed in the direction of arrow G shown in FIG.

  8 to 9, reference numeral 1A denotes a recording head that discharges black pigment ink (hereinafter, mat Bk ink) having a high surface tension, which is suitable for plain paper, matte paper, and the like. Reference numeral 1B denotes a recording head suitable for glossy paper, photographic paper, and the like, which ejects four color (for example, black, cyan, magenta, yellow) color pigment inks that easily penetrate into the paper and have low surface tension. These inks ejected from the recording head 1B often add a resin for fixing the ink on the recording medium, and these color pigment inks are also referred to as resin pigment inks.

  Reference numeral 2 denotes a carriage that mounts the recording heads 1A and 1B and reciprocates in the directions of arrows A and F. Reference numeral 3 denotes a rail that guides and holds the carriage 2 in the directions of arrows A and F.

  Further, 4A is a rubber cap for sealing (capping) the nozzle 1Aa of the recording head 1A, and 4B is a rubber cap for sealing (capping) the nozzle 1Ba of the recording head 1B. The rubber caps 4A and 4B are moved in the directions of arrows B and C by a maintenance motor (not shown). When the rubber caps 4A and 4B move in the direction of the arrow B, the ink ejection surface of each recording head is capped, and when the rubber caps 4A and 4B move in the direction of the arrow C, the capping direction of the ink ejection surface is released.

  As shown in FIGS. 8 to 9, in-cap absorbing members 9 </ b> A and 9 </ b> B for absorbing and holding ink are provided inside the rubber caps 4 </ b> A and 4 </ b> B, respectively. In order to prevent the viscosity of the ink from increasing by the nozzles 1 </ b> Aa and 1 </ b> Ba and sticking and accumulation, preliminary ejection is performed from these nozzles to the in-cap absorbing members 9 </ b> A and 9 </ b> B at predetermined time intervals. Reference numerals 5A and 5B denote suction pumps for the recording heads 1A and 1B, respectively. A predetermined suction pressure (negative pressure) is generated on the formation surface of the nozzles 1Aa and 1Ba in the capping state, and the nozzles 1Aa are passed through the tubes 6A and 6B. Ink is forcibly sucked from 1Ba. Then, the sucked ink is discharged to the waste ink processing member 8 through the tubes 7A and 7B. A series of these operations is called suction recovery (recovery processing).

  Further, 10A and 10B are cleaning members for the recording heads 1A and 1B, respectively, and these cleaning members are formed of a rubber member such as urethane, butyl, or silicon, or a porous sponge material.

  The cleaning members 10A and 10B can be moved in the directions of arrows D and E by a drive source (not shown). When the cleaning members 10A and 10B move in the direction of the arrow D, they are rubbed against the head surface including the formation surface of the nozzles 1Aa and 1Ba (a → b → c dotted line portion) to perform cleaning (wiping and cleaning). When the cleaning is further completed, the cleaning members 10A and 10B come into contact with the cleaners 11A and 11B (dotted line portions). 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 are moved (retracted) in the direction of the arrow C, and are retracted to positions (not shown) that do not interfere with the cleaning members 10A and 10B.

  In conventional recording apparatuses, there is no problem of durability in each part of the apparatus when dye ink is used. However, when pigment ink is used, the elapsed time until the ink viscosity increases or becomes fixed is reduced. It is shorter than when it is used, and the ink viscosity increases or becomes fixed early.

  Also, the effectiveness of cleaning is worse when pigment ink is used than when dye ink is used. For this reason, even if the ink ejection surface of the recording head is rubbed and cleaned, the ink is deposited in a thin film on the ink ejection surface, and the ink is fixed. Therefore, there has been a technical problem that the head cannot be recovered or is extremely difficult by a normal cleaning operation.

  In general, dye molecules themselves are dispersed (dissolved) in an aqueous solution. However, in pigment inks, pigment particles are generally not hydrophilic but hydrophobic and thus do not dissolve in water. Therefore, in order to impart water solubility to the pigment ink, the pigment particles are adsorbed with a resin, an activator or the like 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.

  Further, since the pigment particles themselves are hydrophobic, when the pigment ink is ejected from the recording head, the ink ejection surface of the recording head tends to be easily wetted by the pigment ink as compared with the dye ink. Further, in the so-called resin dispersion type pigment ink in which the above-described resin is used to disperse the pigment, this tendency is more remarkable because the resin and the resin easily wet the ink discharge port. In addition, when the wiping operation is performed in a state where the pigment particles are present on the ink discharge surface, the ink discharge surface is scraped and damaged, and the ink discharge surface is more easily wetted.

  In this way, when the ink ejection surface gets wet, the ink ejection direction becomes unstable, the positional accuracy of ink droplets adhering to the recording medium is deteriorated, and as a result, the quality of the recorded image is lowered.

  To cope with the above problems, measures have been taken so far, such as applying a so-called water-repellent treatment to repel pigment ink on the ink ejection surface of the recording head. As a result of such measures, the ink ejection direction is stabilized in the initial stage of use of the recording head, but when ink that is easily wet, such as pigment ink, is used, its water repellency gradually deteriorates and the ink ejection direction is unstable. It becomes. Even if the wiping operation is executed, the pigment ink that is easily wetted is spread on the ink discharge surface as a result, so that the water repellency is deteriorated, and as a result, the image quality is deteriorated.

  For this reason, for example, as disclosed in Patent Document 1, a head in which only the periphery of the nozzle is made hydrophilic from the beginning has been proposed as a recording head for pigment ink.

  However, properties such as water repellency or hydrophilicity of the ink ejection 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.

  With regard to the problem of such a change in water repellency or hydrophilic performance of the ink ejection surface, a so-called wet wiping technique disclosed in, for example, Patent Document 2 has been known.

  This is because, for example, a very low volatile solvent such as glycerin or polyethylene glycol (hereinafter referred to as wet liquid) is attached to a wiper that wipes the ink discharge surface, and the ink discharge surface is wiped by the wiper. This prevents changes in wettability of the surface. The wet liquid (1) dissolves the ink with increased viscosity fixed on the ink discharge surface and the film-like deposit, and (2) acts as a lubricant by being interposed between the wiper and the ink discharge surface. (3) A protective film for the ink discharge surface is formed by adhering to the ink discharge surface.

  A detailed description will be given later, and an example of the wet wiping operation will be described below.

  FIG. 10 is a diagram for explaining the operation of wet wiping.

  This figure shows a configuration in which a wet wiping unit is added to the configuration of the head recovery mechanism shown in FIG.

As shown in FIG. 10, a wet wiping unit 25 is provided in the vicinity of the wiper folding position on the right side of the cleaners 11A and 11B. In FIG. 10, 20 is a wet liquid holding section, 21 is a wet liquid transmission section, and 21a is a wiper abutting section that abuts cleaning members (hereinafter referred to as wipers) 10A and 10B to attach the wet liquid to the wiper. The wiper is cleaned by the cleaners 11A and 11B from the left side in the figure, then passes through the cleaners 11A and 11B, moves further in the direction of arrow D, and reaches the wet wiping unit 25 (operation of d → e → f). The wipers 10A and 10B reciprocate left and right, but are arranged so that the wipers 10A and 10B abut against the wiper abutting portion 21a at the folded position as indicated by f. Then, the wet liquid adheres in accordance with a predetermined nip width at the abutting portion 21a (hereinafter, the movement of the wet liquid from the wiper abutting portion to the wiper and the adhesion to the wiper are referred to as “wet liquid transfer”. Say).
Japanese Patent Laid-Open No. 11-334074 JP-A-10-138502

  However, in the recording apparatus equipped with wet wiping as in the conventional example, there is a problem that the transfer amount of the wet liquid to the wiper varies greatly depending on the environment. In other words, in low-temperature and low-humidity environments, the transfer amount decreases from room temperature and normal humidity due to an increase in the viscosity of the wet liquid. End up. This deteriorates the ink ejection performance from the recording head, and as a result, deteriorates the quality of the recorded image.

  This point will be described more specifically based on the result obtained by actually verifying the change of the ink ejection surface of the recording head in the recording apparatus equipped with the wet wiping mechanism as described above. According to this verification, the effect of wet wiping is particularly small in a low-temperature environment and further in a low-humidity environment, and the state of the ink ejection surface changes compared to the initial state. For this reason, in such an environment, the ejection position accuracy of the ejected ink droplets on the recording medium is deteriorated, and as a result, the quality of the recorded image is degraded.

  Furthermore, when the behavior under such a low temperature environment and a low humidity 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 maintained in the recording apparatus for the lifetime of the apparatus in the first place, a liquid having a low saturated vapor pressure in the air, that is, a liquid that does not easily evaporate is preferable. In view of solubility in fixed ink with increased viscosity and wettability with each member of the head, polyhydric alcohols such as glycerin and polyethylene glycol, which are often used as an ink composition, 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. 11 is a diagram showing a temperature viscosity curve of glycerin.

  According to FIG. 11, the viscosity of about 800 cp at room temperature is 2300 cp at 15 ° C. and 7000 cp at 5 ° C., and the viscosity increases rapidly as the temperature decreases.

  Furthermore, these solvents tend to absorb moisture in the air, and the amount of moisture absorbed by the solvent varies greatly depending on the environmental humidity. Therefore, since the moisture content of the wet liquid that has absorbed moisture changes depending on the environmental humidity, the viscosity changes greatly.

  FIG. 12 is a diagram showing temperature viscosity curves of glycerin aqueous solutions having different concentrations.

  According to FIG. 12, when the temperature is 10 ° C., the viscosity is about 10 cp when the glycerin concentration is 50%, 500 cp when the viscosity is 90%, and 4000 cp when the viscosity is 100%. . Moreover, the viscosity change rate with respect to temperature is more remarkable as the glycerin concentration is higher.

  It is preferable to prevent moisture absorption and drying caused by humidity fluctuations by shielding the outer periphery of the wet liquid with a material having low water vapor permeability. However, since the contact portion that transfers the wet liquid to the wiper is always exposed to the outside air, the wet liquid in the vicinity of the contact portion is considered to absorb moisture according to the environmental humidity.

  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 or a low humidity environment. This is because wetting of the wet liquid on the wiper when the wiper comes into contact with the contact portion is insufficient due to viscosity, or when the wiper returns after contacting the wiper, the wet liquid has a high viscosity. It is considered that the wet liquid is difficult to tear from the contact portion.

  Also, even if the transfer amount of wet liquid to the wiper is optimized according to the environment, the deterioration of the performance of the ink ejection surface cannot be completely suppressed. The life of the recording head with respect to the number of times is determined. When the life is reached, even if the user is urged to replace the recording head, prohibiting the user from continuing recording without replacing the recording head causes a great disadvantage to the user. Therefore, it is necessary to prevent the deterioration of the recording quality even when the recording head is used beyond its lifetime.

  In addition, if the recording head is used for a long period of time, the wiper itself deteriorates, and the end of the wiper that contacts the recording head at the time of wiping (hereinafter referred to as an edge) is scraped or falls in a direction in which a force is applied at the time of wiping. The ability will be reduced. As a result, in the same wet wiping operation as before the wiper deterioration, there is a problem that the ink residue can be left on the ink discharge surface of the recording head.

  Furthermore, if the recording device is used for a long time, the wet liquid in the wet liquid holding portion is reduced, and the amount of wet liquid transferred to the wiper is reduced. There is also a problem that the deterioration of the discharge surface is accelerated.

  SUMMARY An advantage of some aspects of the invention is that it provides an inkjet recording apparatus and a head recovery method that employ a wet wiping mechanism that maintains good recovery performance over a long period of time regardless of the operating environment. .

  In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

  That is, a recording head having an ejection port for ejecting ink, a wiper for wiping the ink ejection surface of the recording head, and moving the wiper relative to the recording head, An ink jet recording apparatus having a cleaning means for wiping the recording head, the storage unit storing a processing liquid used for wiping the ink discharge surface of the recording head, and the wiper contacting the ink discharge surface of the recording head. A transfer means that contacts the part and transfers the processing liquid stored in the storage part to a part of the wiper, a detection means that detects the temperature or humidity of the installation environment of the ink jet recording apparatus, and the detection means It has a transfer control means for controlling the transfer amount of the treatment liquid according to the detected temperature or humidity.

  Further, the wiper reciprocates in a predetermined direction, the transfer means is placed at the end of the reciprocation path, and the ink discharge surface of the recording head is located in the middle of the reciprocation path. It is desirable to have a cleaner that removes ink residue adhering to a part of the wiper between the position and the contact position between the ink ejection surface of the recording head and the wiper.

  The transfer control means is a driving means for controlling the transfer amount of the processing liquid to be changed by changing a contact position of the transfer means with a part of the wiper according to the detected temperature or humidity. It is desirable to include. Note that the drive means preferably operates so as to move the transfer means up and down or rotate it.

  The transfer control unit may control to change the transfer amount of the processing liquid by changing a contact time of the transfer unit with a part of the wiper according to the detected temperature or humidity. . Further, the transfer amount of the processing liquid may be controlled to be changed by changing the number of times the transfer unit contacts the part of the wiper according to the detected temperature or humidity.

  The transfer of the processing liquid may be performed by moving the wiper to the position of the transfer unit every time the wiper wipes the ink discharge surface of the recording head. Further, this transfer may be performed by moving the wiper to the position of the transfer means before wiping the ink discharge surface of the recording head by the wiper.

The transfer control means further comprises a first counting means for accumulating the number of wiping operations for the ink ejection surface of the recording head, and a second counting means for accumulating the number of wipers used for the wiping operation. The number of wiping operations performed by the cleaning unit per wiping command may be controlled according to the accumulated results. Furthermore, you may provide the estimation means which estimates the residual amount of the process liquid of the said storage part according to the accumulation result by a 2nd counting means.

  It is desirable that the transfer control means further controls the transfer amount of the processing liquid according to the accumulation result by the second counting means.

  In general, the transfer amount of the treatment liquid is desirably controlled so as to increase at low temperature and low humidity and to decrease at high temperature and high humidity.

  According to another invention, a recording head having an ejection port for ejecting ink, a wiper for wiping the ink ejection surface of the recording head, and moving the wiper relative to the recording head, A head recovery method for an ink jet recording apparatus having a cleaning means for wiping the ink ejection surface of the recording head, the detecting step detecting the temperature or humidity of the installation environment of the ink jet recording apparatus, and the ink ejection surface of the recording head A part of the wiper that comes into contact with a part of the wiper comes into contact with a part of a storage part that stores processing liquid used for wiping the ink discharge surface of the recording head, and the processing liquid stored in the storage part is brought into contact with the contact part. A transfer process for transferring to a part of the wiper through a section, and a transfer control for controlling the transfer amount of the treatment liquid according to the temperature or humidity detected in the detection process. A head recovery method characterized by a step.

  Therefore, according to the present invention, the transfer amount of the processing liquid used for wiping the ink discharge surface of the recording head with respect to a part of the wiper is controlled according to the environmental temperature and humidity of the apparatus. Thereby, the transfer amount of the processing liquid used for wiping the ink discharge surface of the recording head is stabilized, and the wet wiping performance can be maintained even in a poor environment such as low temperature and low humidity. As a result, good image recording can be realized regardless of environmental changes.

  Further, the number of wiping operations and the number of wipers used for the recording head are accumulated, and the number of wiping operations by the cleaning means per wiping command is controlled according to the accumulated result, so that the recording head is kept in a good state for a long period. It becomes possible.

  Hereinafter, preferred embodiments of the present invention will be described more specifically and in detail with reference to the accompanying drawings.

  In this specification, “recording” (sometimes referred to as “printing”) does not represent only the case of forming significant information such as characters and graphics. In addition to this, an image, a pattern, a pattern, or the like is widely formed on a recording medium regardless of whether it is significant involuntary, or whether it is manifested so that a human can perceive it visually, or It also represents the case where the medium is processed.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Further, “ink” (sometimes referred to as “liquid”) should be interpreted widely as in the definition of “recording (printing)”. That is, by being applied on the recording medium, it is used for forming an image, pattern, pattern, etc., processing the recording medium, or processing the ink (for example, solidification or insolubilization of the colorant in the ink applied to the recording medium). It shall represent a liquid that can be made.

  Furthermore, unless otherwise specified, the “nozzle” collectively refers to an ejection port or a liquid channel communicating with the ejection port and an element that generates energy used for ink ejection.

<Description of Inkjet Recording Apparatus (FIG. 1)>
FIG. 1 is an external perspective view showing an outline of the configuration of an ink jet recording apparatus (hereinafter referred to as a recording apparatus) employing wet wiping, which is a typical embodiment of the present invention.

  As shown in FIG. 1, a recording medium 30 such as recording paper is fed into the apparatus main body by a paper feed roller 31. A position (recording position) between the recording head 1 </ b> A and the recording head 1 </ b> B is sandwiched between the recording roller 1 </ b> A and the recording head 1 </ b> B by controlling the rotation of the conveying roller 32. ). At this time, an image (including characters and the like) is recorded by reciprocally scanning the recording heads 1A and 1B mounted on the carriage 2 based on the recording information. Further, the home position HP of the carriage 2 is set at a position within the moving range of the carriage 2 and out of the recording area (on the right side of the recording area in FIG. 1).

  Further, a recovery device 35 including a wet wiping mechanism is provided in the vicinity of the home position HP, and a temperature and humidity sensor 36 composed of general-purpose products is provided in the vicinity of the recovery device 35 and in the main body side plate.

<Control Configuration of Inkjet Recording Apparatus (FIG. 2)>
FIG. 2 is a block diagram showing a control configuration of the recording apparatus shown in FIG.

  As shown in FIG. 2, the controller 600 includes an MPU 601, a ROM 602, a special purpose integrated circuit (ASIC) 603, a RAM 604, a system bus 605, an A / D converter 606, and the like. Here, the ROM 602 stores a program corresponding to a control sequence to be described later, a required table, and other fixed data. The ASIC 603 generates control signals for controlling the carriage motor M1, the transport motor M2, and the recording heads 1A and 1B. The RAM 604 is used as a development area for image data, a work area for program execution, and the like. A system bus 605 connects the MPU 601, the ASIC 603, and the RAM 604 to each other to exchange data. The A / D converter 606 inputs analog signals from the sensor group described below, performs A / D conversion, and supplies a digital signal to the MPU 601.

  In FIG. 2, reference numeral 610 denotes a computer (or a reader for image reading, a digital camera, etc.) serving as a supply source of image data, and is collectively referred to as a host device. Image data, commands, status signals, and the like are transmitted and received between the host device 610 and the recording device via an interface (I / F) 611. This image data is input in a raster format, for example.

  Reference numeral 620 denotes a switch group, which includes a power switch 621, a print switch 622, a recovery switch 623, and the like. The print switch 622 is used for instructing the start of printing. The recovery switch 623 is used to instruct the start of processing (recovery processing) for maintaining the ink ejection performance of the recording heads 1A and 1B in a good state. These switches are used to receive command inputs from the operator.

  Reference numeral 630 denotes a sensor group for detecting the apparatus state, and includes a position sensor 631, a temperature / humidity sensor 36, and the like. The position sensor 631 is a sensor for detecting a home position h such as a photocoupler, and the temperature / humidity sensor 36 is a sensor used for detecting the environmental temperature and humidity of the printing apparatus.

  Further, 640 is a carriage motor driver that drives a carriage motor M1 for reciprocating scanning of the carriage 2 in the direction of arrow A, and 642 is a conveyance motor driver that drives a conveyance motor M2 for conveying the recording medium P.

  Embodiments according to the present invention in the following order: [1] overview of recovery device 35, [2] overview of recording head, [3] description of operation of recovery device including wet wiping, [4] description of important parts regarding wet wiping The wet wiping mechanism used in the above will be described.

[1] Outline of Recovery Device The recovery device 35 is provided in the vicinity of the home position HP as shown in FIG. The recovery device 35 is a rubber cap that seals the nozzle by contacting (contacting) the ink ejection surfaces (surfaces on which the nozzles are formed) of the recording heads 1A and 1B, and sucking negative pressure to the ejection port through the cap in a capped state. It has a suction pump that can generate force. In addition, a wiper or the like for scraping (wiping off) adhering matters such as ink and dust by rubbing on the ink ejection surface is also provided.

  The head recovery device 35 generates a negative pressure in the cap by a suction pump in a state where the ink discharge surface of the recording head is capped, and this negative pressure causes ink having increased viscosity along with ink from the discharge port, bubbles, fixed ink, and dust. Dust and remove foreign matter such as. Thereby, the recovery device 35 recovers the ink ejection performance of the recording head.

[2] Overview of recording heads The recording heads 1A and 1B are ink jet recording heads that eject ink using thermal energy, and include an electrothermal transducer for generating thermal energy. Then, film boiling occurs in the ink by the heat energy generated from the electrothermal transducer, and ink is ejected from the ejection port using the pressure change caused by the growth and contraction of bubbles generated at that time, and recording is performed.

[3] Description of operation of recovery device including wet wiping The recovery device 35 includes a wet wiping unit. Further, since the basic mechanism and sequence operation of the recovery device 35 and the wet wiping using the same are the same as those described in the conventional example, the description thereof is omitted, and here, the characteristic of the embodiment of the present invention is described. Only the configuration and operation will be described with reference to FIGS.

  FIG. 8 is a diagram illustrating the state of the recovery device when the recording apparatus is powered off or in standby. In such a state, the recording head 1A is opposed to the cap 4A, and the recording head 1B is opposed to the recording head cap 4B to cap the respective ink ejection surfaces. In this way, the caps 4A and 4B are at the recording head protection position, and suppress the adhesion of dust or the like to the ink discharge surface and the evaporation of moisture from the nozzles.

  On the other hand, when the recording signal is received from the host device, the caps 4A and 4B move in the direction of the arrow C, the cap is opened, and the carriage 2 is ready for scanning. FIG. 10 is a diagram showing a state of the cap open state.

  Recording is performed by scanning the carriage 2 along the rail 3, but during the recording, preliminary ejection onto the cap is performed as a recovery operation. The in-cap absorbing members 9A and 9B are each formed of a porous material or sponge-like material that can absorb and hold ink. In the cap open state during recording, the caps 4A and 4B are held at positions separated from the recording heads 1A and 1B, and ink is reserved from the nozzles 1Aa and 1Ba of the recording heads 1A and 1B toward the in-cap absorbing members 9A and 9B. Discharge.

  This preliminary ejection is an operation for preventing the ink viscosity in the nozzles 1Aa and 1Ba from increasing and fixing during the recording, and is usually performed at a predetermined time interval. Note that this preliminary discharge may be performed toward a preliminary discharge receiver (not shown). The preliminary discharge receiver can be constituted by, for example, a container or an ink absorbing member.

  The suction recovery is executed in consideration of necessity, such as immediately before the start of recording, every predetermined amount of time during recording or every recording operation, or when it is detected that the recovery operation of the recording head is necessary. .

  As shown in FIG. 10, after the wipers 10A and 10B are cleaned by the cleaners 11A and 11B from the left side in the drawing, they pass through the wiper 10A and reach the wet wiping unit 25, and the wiper contact portion 21a has a predetermined nip width. Accordingly, the wet liquid is transferred to the wipers 10A and 10B.

  After the transfer of the wet liquid, the wipers 10A and 10B return again from the position f to the position a, and stop at the standby position of the wiper at the position a. During this movement, the cleaners 11A and 11B are controlled to retract from the wiper movement path by a mechanism (not shown). Further, the carriage 2 is also moved from the wiping position so that the ink discharge surface of the recording head is not wiped by the surface opposite to the wiping surface of the wipers 10A and 10B.

  As can be seen from the above sequence, at the time of the first wiping, wiping is performed in a state where the wet liquid is not transferred to the wiper, and the next wet using the wet liquid transferred to the wiper by a series of operations at that time. Wiping will be performed. Since the wet liquid is not volatile, it does not evaporate and disappear by the next wiping. Further, since the wet liquid has a viscosity much higher than that of ink used in a normal recording apparatus, it does not flow out after adhering to the wiper. Further, the change in the state of the ink ejection surface of the recording head due to the first dry wiping (wiping without using a wet liquid) can be ignored when compared with the number of wiping durability during the lifetime.

  The present invention is not limited to the wet wiping mechanism configured as described above. For example, the present invention is effective for a recording apparatus having a wet wiping mechanism using a rotating wiper as shown in Patent Document 2, or for other configurations different from the above in which the wiper slides. For example, in the slide wiper mechanism as described above, a folding position may be provided between the positions e and f and the return position to the stop position a may be provided. With such a configuration, the wiping process including the transfer of the wet liquid (the process of returning to the position a after moving to the position f) and the transfer of the wet liquid are not included (the return to the folding position a between the positions e and f). ) Wiping process can be selectively used.

[4] Explanation of important parts related to wet wiping Important elements for realizing wet wiping are the wet liquid, its holding / transmitting part, the state of the ink ejection surface of the recording head, and the ink used.

  The wet liquid holding part (wet liquid storage part) 20 shown in FIG. 10 holds 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 appropriately selected. The wet liquid transmission part 21 is a transmission member that transmits wet liquid from the PP sponge and transmits the wet liquid to the wiper contact part 21a. Therefore, the wet liquid transmission part 21 includes the contact part 21a. Here, Asahi Kasei Sun Fine AQ900 is used as the transmission member of the wet liquid transmission unit 21.

  In order to ensure that the wet liquid is supplied between the wet liquid holding unit 20 and the transmission member, the capillary force of the transmission member is stronger than the capillary force of the wet liquid holding unit 20 with respect to the capillary force. There must be. 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, glycerin is used as the wet liquid. Although glycerin itself is difficult to evaporate, it easily absorbs moisture in the air, and has the property of releasing moisture even in a low-humidity environment once it has absorbed moisture. For this reason, it is preferable to shield the outer periphery of the wet liquid holding unit 20 and the wet liquid transmission member 21 with a material (not shown) having a low water vapor permeability 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 bubbles existing in the wet liquid holding unit 20.

  As described above, the wiper contact portion 21a for supplying the wet liquid to the wiper is always in contact with the outside air, although the influence of the moisture absorption and drying of the wet liquid by the outside air is eliminated as much as possible. It is considered that the wet liquid that is not volatile and does not easily evaporate also comes into contact with the outside air for a long time, so that the wet liquid near the wiper contact portion 21a is slightly absorbed and dried according to the environmental humidity.

  The wipers 10A and 10B use polyether urethane, and the surface of the ink discharge surface of the recording head is coated with a water repellent material to provide water repellency.

  As described in the conventional example, the ink used is a self-dispersible matte Bk ink for the recording head 1A. 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 recording 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 20, that is, the volume of the holding part calculated backward from the necessary amount of the wet liquid is calculated as follows. First, even if wet wiping is performed a number of times corresponding to the durability limit of the recording device, it is necessary because the water-repellent state of the ink discharge surface of the recording head does not change significantly and the droplet discharge position accuracy is within the allowable range. The amount of wet liquid transferred is determined experimentally. Next, this is multiplied by the number of wipings corresponding to the durability limit to obtain a necessary wet liquid volume, which is defined as the volume of the wet liquid holding part.

  For example, assume that one wet wipe is performed each time one sheet of recording paper is recorded. Based on this assumption, 1 mg of wet liquid is transferred to the wiper in one wet wipe and applied to the ink ejection surface of the recording head, and 50,000 sheets of recording paper are reached before reaching the durability limit of the recording apparatus. If it is possible to record normally, the required amount of wet liquid is 50 g.

  In consideration of the density of the wet liquid, the wet liquid holding amount of the PP sponge, the wet liquid holding amount of the transmission member, the remaining amount when the wet liquid is used up, the volume of the wet liquid holding portion needs to be about 60 cc. . The initial wet liquid injection amount depends on the exhaustion efficiency, and normally 100% use-up cannot be expected. Therefore, it is necessary to inject about 1.2 times the required amount. Note that the amount of wet liquid required for one wiping, the number of sheets that can be recorded to the end of the durability of the recording device, the amount of wet liquid retained by the PP sponge and transmission member, etc. vary depending on the requirements of each recording device. The value of should be set appropriately.

  In addition, this invention is not applied only to the above structures. For example, a material such as a wet liquid, a wet liquid holding portion, a wet transmission member, a state of an ink discharge surface of a recording head (water repellency / non-water repellency / hydrophilicity, etc.), an ink surface tension that is an index of ink wettability, Various changes such as the contact angle of ink with respect to the ink ejection surface are possible. Therefore, it goes without saying that the present invention is applicable to various embodiments according to such changes. Regarding the ink, in this embodiment, the pigment ink is used as an example. However, the present invention can be applied even to a dye ink.

  Hereinafter, various embodiments relating to the transfer amount control of the wet liquid to the wiper in a low-temperature environment or a low-humidity environment, which is a characteristic configuration of the present invention, and depending on the deterioration of the recording head and the wiper during long-term use An embodiment relating to control of wet wiping conditions will be described.

  In this example, the wiper abuts by mechanically moving the wet wiping unit up and down according to the temperature and humidity detected by the humidity sensor and changing the amount of penetration when the wiper abuts against the wiper abutment portion. Change the nip width of the part and adjust the transfer amount of wet liquid.

  FIG. 3 is a diagram illustrating a wet wiping unit mechanism according to the first embodiment. In FIG. 3, the same reference numerals and reference symbols are assigned to the components and matters already described, and the description thereof is omitted. Here, only the characteristic configuration and operation of this embodiment will be described.

  In FIG. 3, 22 is a rotating shaft, and 23 is an eccentric cam that rotates as the rotating shaft 22. The wet wiping unit 25 is supported by the eccentric cam 23 and can move up and down in the direction of the arrow H. The MPU 601 and a maintenance motor (not shown) move up and down according to the temperature and humidity detected by the temperature / humidity sensor 36 to control the amount of penetration of the wipers 10A and 10B into the wet contact portion 21a.

  Table 1 is a wiper penetration amount table showing the amount of wiper penetration according to the detected temperature and humidity.

  In Table 1, the amount of penetration of the wiper at a temperature of 20 ° C. to 30 ° C. and a humidity of 40% to 70% is defined as a standard value (Ref), and the amount of change according to the temperature and humidity from the standard value (Ref) is shown. . By controlling the wiper penetration amount using such values, optimal values are set for the detected temperature and humidity.

  Table 2 is a table showing the transfer amount per wiping when the wiper penetration amount is controlled according to the values in Table 1.

  According to Table 2, for example, at a temperature of 20 ° C. to 30 ° C. and a humidity of 40% to 70%, the transfer amount at 25 ° C. and 55%, which are the respective centers, is 1.0 mg.

  Table 3 is a table showing the transfer amount of the wet liquid when the wiper penetration amount is not controlled.

  According to Table 3, for example, the transfer amount is about 0.4 mg at 25 ° C. and 30%. This value is about 40% of the value at 25 ° C. and 55%, which are typical values of normal temperature and normal humidity. Thus, it is suggested that the desired wet wiping performance cannot be exhibited unless the wiper penetration amount is controlled.

[Table 1] Wiper penetration control table

[Table 2] Transfer amount table after wiper penetration control (experimental value)

[Table 3] Transfer amount table when wiper penetration control is not performed (experimental value)

  On the other hand, as can be seen from Table 2, when the control according to this embodiment is performed, the wet wiping unit 25 is lowered by 0.6 mm in an environment of 25 ° C. and 30%, and accordingly the amount of penetration of the wiper is also 0.6 mg. To increase. For this reason, the nip width of the wipers 10A and 10B contacting the wiper contact portion 21a is increased, and the transfer amount is 1.0 mg, which is the same value as normal temperature and normal humidity.

  In addition, since drying of the ink discharge surface of the recording head is promoted at high temperatures and low humidity, solid ink residue remains on the ink discharge surface at the same amount of wet liquid transferred as in other environments. Wiping residue may occur. For this reason, it is necessary to increase the transfer amount at higher temperatures and lower humidity than in other environments. According to Table 1, for example, when the wiper penetration amount is +0.8 mm at a temperature of 35 ° C. and a humidity of 10%, the transfer amount of the wet liquid is 1.3 mg from Table 2. As a result, even when the drying of the ink discharge surface is promoted, the transfer amount is controlled to be sufficient to exhibit the desired wet wiping performance.

  On the other hand, in a high temperature or high humidity environment, the wet wiping unit 25 is raised, and the wiper penetration amount is reduced with respect to the standard value (Ref), thereby suppressing transfer of the wet liquid more than necessary. For example, consider an environment of 35 ° C. and 85%. In this case, if the wiper penetration amount control is not performed, the transfer amount is 2.8 mg as shown in Table 3, whereas if the wiper penetration amount control is performed, the wiper penetration amount is 0. As shown in Table 1. As a result, the transfer amount is 1.7 mg as shown in Table 2. In this way, the transfer amount is suppressed.

  Therefore, according to this embodiment, it is possible to adjust the wet liquid transfer amount by changing the touch width of the wiper contacting the wiper contact portion according to the environment. As a result, the amount of wet liquid to be accommodated at the time of shipment of the recording apparatus can be made as small and appropriate as possible.

  In this embodiment, the wet wipe unit is moved up and down, but the amount of penetration of the wiper into the contact portion 21a may be changed by moving the wet wipe unit left and right.

  The return position f of the wiper is mechanically fixed. Therefore, as shown in FIG. 3, when the wiper abutting portion 21a is arranged at an angle other than horizontal, for example, 45 ° with respect to the movement direction of the wiper, it moves not only vertically but also horizontally (carriage scanning direction). The amount of penetration of the wiper can be varied.

  Thus, according to this embodiment, the environmental temperature and humidity are detected by the temperature / humidity sensor 36, and the amount of penetration of the wiper into the wet wiping unit is varied according to the temperature and humidity. Thereby, for example, the viscosity of the wet liquid in a low-temperature or low-humidity environment changes to correct the decrease in the transfer amount, and the desired wet wiping performance can be maintained.

  As a result, even if wiping is performed while the recording device is in use, the state of the ink discharge surface of the recording head is maintained well, and the ink droplet discharge accuracy is maintained well until the end of its use period, resulting in high quality. Record can be maintained.

  The configuration of the wet wipe unit is not limited to the above configuration. For example, a configuration as shown in FIG. 4 may be adopted in order to save the space of the wet wipe unit.

  In this embodiment, the amount of wet liquid transferred to the wiper is controlled according to the detected temperature and humidity. However, the wet liquid is transferred according to the temperature or humidity by a sensor that detects the temperature or humidity. The amount to be controlled may be controlled. This is because the thickened state of the wet liquid can be estimated to some extent even from temperature or humidity alone. Thus, cost can be reduced by using a sensor that detects only the temperature or temperature instead of the temperature and humidity sensor.

  FIG. 4 is a diagram illustrating a wet wiping unit mechanism according to a modification of the first embodiment. In FIG. 4, the same reference numbers and reference symbols are assigned to the components and matters already described, and the description thereof is omitted. Here, only the characteristic configuration and operation of this embodiment will be described. As can be seen from a comparison between FIG. 4 and FIG. 3, in this example, unlike the configuration shown in FIG. 3, the wet wipe unit 25 is configured to rotate about the rotation shaft 24. By using such a rotation mechanism, space saving can be achieved.

  That is, in this example, the amount of penetration of the wiper into the abutting portion 21a is changed to be substantially the same as that of the first embodiment without narrowing the operating range without having a space for the vertical movement of the wet wipe unit 25. Can do.

  This configuration is the same in that the amount of intrusion is controlled by rotating the wet wipe unit 25 according to the installation environment of the recording apparatus, that is, the temperature, the detection temperature of the humidity sensor 36, and the humidity. Note that the degree of change in the wiper penetration amount according to the detected temperature and humidity may be set as appropriate so that the desired wet wiping performance can be maintained.

  In this embodiment, the wet wiping sequence is changed in accordance with the detected temperature and humidity to correct a decrease in the transfer amount of the wet liquid in a low temperature and low humidity environment.

  FIG. 5 is a flowchart showing a wet wiping sequence according to the second embodiment.

  According to FIG. 5, it is confirmed in step S100 that the recording heads 1A and 1B and the wipers 10A and 10B are at the wiping position. In step S110, the wipers 10A and 10B are moved to perform wiping.

  In step S120, the wipers 10A and 10B are further moved in the direction of arrow D, and are brought into contact with the wiper contact portion 21a at the turn-back position f. In step S130, the movement of the wipers 10A and 10B is stopped at the contact position for a predetermined time. During this stop, the wiper contacts the wiper abutting portion 21a at the wiper folding position f, and the wet liquid is transferred.

  When the time elapses, the process retreats the recording heads 1A and 1B to a position where the wipers 10A and 10B do not hit in step S140. In step S150, the wipers 10A and 10B are moved in the direction of arrow E to return to the wiper home position (HP).

  The stop (transfer) time is changed according to the temperature and humidity of the installation environment of the recording apparatus.

  Table 4 is a table showing wiper stop time according to temperature and humidity.

[Table 4] Wiper stop time table

  Table 5 is a table showing the transfer amount according to the wiper stop time shown in Table 4.

[Table 5] Transfer amount after wiper stop time control (experimental value)

  Table 6 is a table showing the transfer amount when the wiper stop time is not controlled.

[Table 6] Transfer amount (experimental value) table when wiper stop time control is not performed

  In this embodiment, the values shown in Table 4 are used to change the transfer time of the wet liquid according to the environmental temperature and humidity, thereby correcting the decrease in the wet liquid transfer amount at low temperature and low humidity. As can be seen from Table 4, a longer transfer time is provided to ensure the transfer amount of the wet liquid at lower temperatures and lower humidity.

  As can be seen from Tables 4 to 5, no transfer time for the wet liquid is positively provided at room temperature and normal humidity. For example, when the temperature is 20 to 30 ° C. and the humidity is 40 to 70%, the wiper is reversed after 0.1 seconds, which is the time required for the recording head to be retracted, so that the transfer time is as short as 0.1 seconds. The transfer amount is 1.0 mg.

  In contrast, according to Table 6, the transfer amount when the transfer time (that is, wiper stop time) is not controlled is 0.2 mg at a temperature of 15 ° C. and a humidity of 30%. Compared with the case where the transfer time (wiper stop time) is controlled at the same environmental temperature and humidity, the transfer amount is greatly reduced.

  Therefore, in this embodiment, the wiper stop time (contact time to the wiper contact portion) is set to 6 seconds according to Table 4 in an environment of temperature 15 ° C. and humidity 30%. Thereby, the transfer of the wet liquid is promoted, and as a result, as shown in Table 5, the transfer amount is restored to 0.9 mg.

  The wiper stop time (contact time to the wiper contact portion) is appropriately determined depending on the low temperature of the wet liquid, the degree of viscosity increase at low humidity, the wiper material, the contact member material, the structure of the mechanism portion, and the like. It should be set.

  As described above, in this embodiment, the amount of wet liquid transferred is controlled by controlling the contact time of the wiper with the wet liquid in a low temperature and low humidity environment. There is no need to have. Therefore, compared with the first embodiment, the mechanical configuration can be omitted, which contributes to cost reduction and downsizing of the recovery device.

  In this example, as can be seen from Table 4, the transfer time in a high temperature and high humidity environment is equivalent to the normal temperature (20 to 30 ° C.). You may make it suppress the increase in the transfer amount of the wet liquid in an environment. By doing so, since a large amount of wet liquid is not used at high temperatures, the amount of wet liquid to be accommodated at the time of shipment of the recording apparatus can be made as small and appropriate as possible as in the first embodiment.

  Furthermore, in addition to the processing described above, the wet liquid may be transferred immediately before the wiping operation.

  FIG. 6 is a flowchart showing a wiping sequence according to a modification of the second embodiment. As can be seen by comparing FIG. 6 and FIG. 5, processing steps S <b> 10 to S <b> 60 for adding the wiper to the wiper contact portion with the recording head retracted are added to the sequence shown in FIG. 5. Only the additional steps will be described below.

  That is, after the recording head is retracted from the wiper movement path in step S10, the wipers 10A and 10B are moved in step S20.

  In step S30, the wipers 10A and 10B are brought into contact with the wiper contact portion 21a at the turn-back position (position f in FIG. 3). In step S40, the wipers 10A and 10B are stopped for the transfer time for transferring the wet liquid.

  In step S50, the wipers 10A and 10B are returned to their home positions (HP).

  In step S60, it is checked whether or not the processes in steps S10 to S50 have been completed a predetermined number of times. If it is determined that the predetermined number of times has not been completed, the process returns to step S10 and the processes of steps S10 to S50 are repeated a predetermined number of times. On the other hand, if it is determined that the process has been repeated a predetermined number of times, the process proceeds to step S100, and the above-described process is executed.

  As described above, when the wet liquid is transferred immediately before the wiping operation, the function of the wet wiping can be more reliably exhibited. Further, the transfer amount can be increased by repeating the transfer of the wet liquid a plurality of times.

  In the first and second embodiments, the transfer amount of the wet liquid is controlled. In this embodiment, a method for suitably maintaining the ink discharge surface of the recording head by changing the number of wiping operations per wiping operation will be described.

  FIG. 7 is a flowchart illustrating a wiping sequence according to the third embodiment. Of the processing steps in the flowchart, the same processing steps as those already described are denoted by the same step reference numerals, and the description thereof is omitted.

  A comparison between FIG. 7 and FIG. 5 is that this process is characterized in that the normal wiping sequence is repeated a plurality of times in step S160. The number of repetitions of wiping is controlled so as to increase as the environmental temperature and humidity decrease.

  Since the transfer amount of the wet liquid to the wiper is sufficient at normal temperature and normal humidity, the ink discharge surface can be cleaned by one wiping operation. However, when the viscosity of the wet liquid is high at low temperature and low humidity, the amount of transfer to the wiper is small, so that the wet wiping effect cannot be fully achieved with one wiping, and the viscosity increases on the ink ejection surface of the recording head. The left ink residue is left behind.

  In this embodiment, therefore, the wiping residue is removed by making the number of wiping repetitions a plurality of times, so that the ink discharge surface of the recording head is kept good.

  In addition, it is possible to perform more suitable control by combining the control of considering the transfer time with the control of the number of wiping repetitions according to the environmental temperature and the humidity.

  Further, this embodiment can be implemented with the same mechanism configuration as that of the second embodiment, and has an advantage that it can be implemented with a relatively simple control configuration as compared with the modification of the second embodiment shown in FIG. .

  According to the flowchart of FIG. 6, there are (1) wiper movement with wiping of the recording head and (2) wiper movement for repeated transfer of wet liquid without performing wiping. In the case of (1), it is necessary to bring the cleaners 11A and 11B into contact with the wiper for wiper cleaning after wiping. On the other hand, in the case of (2), it is necessary to retract the cleaners 11A and 11B to a position where they do not contact the wiper.

  As described above, in the control shown in FIG. 6, the position of the cleaners 11 </ b> A and 11 </ b> B is controlled with respect to the movement of the wiper in the same direction, so that the control becomes complicated mechanically. On the other hand, in this embodiment, since the position control of the cleaner is not required, the function of wet wiping can be enhanced with a relatively simple mechanism configuration.

  By the wet wiping control as described above, it is possible to suppress the deterioration of the ink ejection surface of the recording head and to extend the durable life of the head.

  However, the deterioration gradually proceeds with the use of the recording head, and at some point, the original performance cannot be exhibited. Similarly, the wiper also causes the edge to be scraped or fallen with its use.

  Therefore, in this embodiment, the degree of deterioration of the ink ejection surface and the wiper of the recording head is estimated from the number of wiping operations, and the number of wet wipings is changed accordingly to cope with the deterioration of the ink ejection surface and the wiper of the recording head. The wiping operation is performed.

  Here, the case where the wiper has a wiping durability life of 50,000 times and the recording head has a wiping durability life of 10,000 times will be described as an example.

  As the wiping sequence at this time, the normal wiping sequence is repeated a plurality of times as already described with reference to FIG.

  Table 7 is a table showing the relationship between the number of wiping times of the recording head and the wiping frequency change value, and Table 8 is a table showing the relationship between the number of times the wiper is used and the wiping frequency change value.

[Table 7]

[Table 8]

  According to Table 7, when wiping more than 10,000 times corresponding to the life of the recording head is performed, wiping is performed +1 time for a predetermined number of wiping (usually once) per subsequent wiping command. To be controlled.

  According to Table 8, when 50,000 times or more, which is the durable life of the recording apparatus main body, is performed, +1 wiping is performed for a predetermined number of wiping (usually once) per subsequent wiping command. To control.

  Since the print head is replaceable, the number of wiping times of the print head and the number of wiping uses of the wiper are counted separately, and when the print head is replaced, only the number of wiping times of the print head is reset and counted again from zero. To do.

  Thus, the degree of deterioration of the recording head and the wiper is estimated from the number of wiping operations, and the number of wiping operations for one wiping command is controlled according to the number of wiping operations. As a result, even if the water repellency of the ink discharge surface of the recording head deteriorates or the edge of the wiper is shaved, the ink discharge surface of the recording head can be cleaned normally, and high-quality recording is maintained. be able to.

  In this embodiment, the number of wiping operations is controlled according to the number of wiping operations of the recording head and the number of times the wiper is used. However, the present invention is not limited to this. For example, the amount of penetration of the wiper and the transfer time of the wet liquid may be controlled. In addition, although the change in the number of wiping operations has been described as two stages before and after the endurance life, it can also be divided and controlled more finely.

  Further, in addition to the control based on the environmental temperature and humidity described in the first and second embodiments, the control described in this embodiment can be performed in combination. That is, the amount of wiper penetration and the transfer time may be controlled according to the environmental temperature and humidity, and the number of wiping operations may be changed according to the number of wiping times of the recording head and the number of times the wiper is used. Accordingly, it is possible to perform a wiping operation in consideration of deterioration of the recording head and the wiper while suppressing a change in the transfer amount of the wet liquid due to an environmental change.

  Here, in addition to the control described in the third embodiment, a wet wiping control that considers a variation in the amount of wet liquid transferred to the wiper due to a change in the remaining amount of wet liquid will be described.

  Depending on the configuration of the wet wiping unit, the transfer amount to the wiper may decrease as the remaining amount of the wet liquid decreases. For example, in the case of a configuration in which the water head difference with respect to the wiper contact portion changes as the remaining amount of wet liquid decreases, the meniscus strength of the wet liquid transfer portion changes according to the remaining amount. In particular, when the remaining amount of the wet liquid is small, the meniscus at the wiper contact portion is strong, so that the transfer amount to the wiper is reduced from a predetermined amount.

  In this embodiment, even in such a case, the following control is executed so as to secure a necessary transfer amount to the wiper.

  First, the remaining amount of wet liquid is detected. For this reason, the consumption amount of the wet liquid is estimated from the number of wiping operations. This estimation is performed, for example, by subtracting 1 mg from the initial value for each wiping when the initial value of the wet liquid is 50 g and the transfer amount by one wiping is set to a maximum of 1 mg. . Therefore, the remaining amount of the wet liquid is estimated from the number of times the wiper is used for wiping, as well as the deterioration of the recording head and the wiper.

  Table 9 is a table showing the relationship among the number of wiper wiping use times, the wiping frequency change value, the wet liquid remaining amount estimated value, and the wiper penetration amount change value.

[Table 9]

  Table 9 is an estimate of the remaining amount of wet liquid, and a change value is added to the amount of penetration of the wiper with respect to the wiper contact portion.

  According to Table 9, for example, when the number of times that the wiper is wiped is 45000 times, the amount of wet liquid transferred to the wiper decreases if the wiper penetration amount remains at the standard value (Ref). The amount is increased by 0.2 mm to increase the transfer amount.

  Further, when the number of wiping uses corresponding to the durable life of the recording apparatus is 50000 times or more, the estimated amount of remaining wet liquid is 0 g. However, since the amount with a certain margin is actually injected, the number of wiping uses is 50000. The wet liquid does not run out immediately after the operation. Further, in this embodiment as well, in the same manner as in the third embodiment, since the wiper is predicted to deteriorate when the number of wipers exceeds 50,000 times, control is performed so that wiping is performed +1 times for a predetermined number of wiping per subsequent wiping command.

  As described above, according to this embodiment, the remaining amount of wet liquid can be estimated from the number of times the wiper is used, in addition to the deterioration of the recording head and the wiper. And the fall of the transfer amount to the wiper of wet liquid can be suppressed by changing the wiper penetration | invasion amount with respect to the wiper contact part according to the residual amount. As a result, the ink discharge surface of the recording head can be normally cleaned, and the recording quality can be maintained.

  In this embodiment, the transfer amount of the wet liquid is adjusted by controlling the wiper penetration amount, but the present invention is not limited to this. For example, the transfer amount may be increased by changing the transfer time or the number of times of transfer of the wet liquid.

  Further, in addition to the control based on the environmental temperature and humidity described in the first and second embodiments, the control described in this embodiment can be performed in combination. That is, the transfer time is controlled according to the environmental temperature and humidity, the number of wiping operations is controlled with respect to the deterioration of the recording head and the wiper estimated from the number of wiper uses, and the wiper penetration amount is controlled according to the remaining amount of wet liquid. As a result, it is possible to suppress a change in the transfer amount due to the remaining amount of wet liquid and the environmental conditions, and to perform a wiping operation based on the deterioration of the recording head and the wiper.

  In the embodiment described above, the timing for executing the wet wiping operation is not described, but this operation may be performed at the timing of timer wiping or dot count wiping as in the conventional case.

  The timer wiping is wiping that is executed when it is determined that the ink ejection surface may be dry when the cap open state of the recording head continues for a predetermined time. In addition, the dot count wiping is a wiping that is executed when it is determined that there is a possibility that the ink ejection surface is contaminated with ink mist when the number of ink droplets ejected is counted and recording exceeds a predetermined amount. is there.

  In addition to this, wet wiping may be performed at a timing before the cap is closed. This is wiping for removing the ink adhering to the ink discharge surface of the recording head before the cap closing that has been conventionally performed and preparing for the subsequent standing.

  Furthermore, it is also preferable to perform wet wiping to remove a relatively large amount of ink adhering to the ink ejection surface of the recording head by the suction recovery operation after the suction recovery operation that is performed after leaving the recording apparatus for a long period of time.

  In the above embodiment, the number of wiping operations performed in one wiping operation is specified according to the number of wiping operations of the wiper and the recording head. However, even if the frequency of performing the wiping operation is changed according to the deterioration of the recording head and the wiper. Good. Specifically, when the number of wiping times exceeds a predetermined number, the predetermined time for triggering the wiping operation in timer wiping may be shortened, or the predetermined number of ejections in the trigger may be reduced in dot count wiping. Further, the trigger for entering the wiping operation may be changed when the total number of ejections from the recording head exceeds a predetermined number. Even in this case, even if the ink discharge surface of the wiper or the recording head is deteriorated, an appropriate cleaning operation can be performed.

  As described above, according to the present invention, the temperature and humidity are detected by the temperature and humidity sensor in the installation environment of the recording apparatus, the mechanical position of the wet liquid transfer unit is controlled in a low temperature and low humidity environment, and the wet liquid is controlled. Controls the transfer time and the number of wiping operations during transfer. Thereby, it is possible to correct a decrease in the transfer amount due to an increase in the viscosity of the wet liquid in a low temperature and low humidity environment, and to realize an optimal wet wiping sequence according to the decrease in the transfer amount. As a result, the wet wiping performance can be maintained and the ink discharge surface of the recording head can be normally cleaned.

  Furthermore, even after a long-term use of the recording head, the contact position of the wiper with respect to the wet transfer portion and the wet wiping sequence can be controlled according to the deterioration of the recording head and wiper and the decrease in the remaining amount of wet liquid. , Wet wiping performance can be maintained.

  Therefore, the change in the ink discharge surface state (water repellency deterioration and hydrophilicity change) due to wiping while using the recording device is reduced, and even if the state change occurs, it is optimal to match the change Control can be performed. As a result, accurate ink ejection can be realized and high-quality image recording can be maintained even when the recording apparatus or the recording head is used for a long period of time.

  In the above embodiments, the liquid droplets ejected from the recording head are described as ink, and the liquid stored in the ink tank is described as ink. However, the storage is limited to ink. It is not a thing. For example, a treatment liquid discharged to the recording medium may be accommodated in the ink tank in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

  The above embodiments are provided with means (for example, an electrothermal converter, a laser beam, etc.) for generating thermal energy as energy used for performing ink ejection, particularly in the ink jet recording system. The thermal energy causes a change in the state of the ink, thereby achieving high recording density and high definition.

1 is a schematic configuration diagram of an ink jet recording apparatus that is a typical embodiment of the present invention. FIG. 2 is a block diagram illustrating a control configuration of the recording apparatus illustrated in FIG. 1. It is a figure explaining the wet wiping mechanism according to Example 1. FIG. It is a figure explaining the wet wiping mechanism according to the modification of Example 1. FIG. 10 is a flowchart showing a wet wiping sequence according to the second embodiment. 10 is a flowchart showing a wet wiping sequence according to a modification of the second embodiment. 10 is a flowchart illustrating a wet wiping sequence according to a third embodiment. It is sectional drawing which shows the structure of the recovery mechanism of the conventional inkjet recording device. It is a sectional side view which shows the structure of the recovery mechanism of the conventional inkjet recording device. It is a figure explaining the conventional wet wiping mechanism. It is a figure which shows the temperature-viscosity curve of glycerol. It is a figure which shows the temperature-viscosity curve of the glycerol aqueous solution from which glycerol concentration differs.

Explanation of symbols

1A, 1B Recording head 1Aa, 1Ba Nozzle 2 Carriage 3 Rail 4A, 4B Cap 5A, 5B Suction pump 6A, 6B, 7A, 7B Tube 8 Waste ink processing member 9A, 9B Absorbing member 10A in cap, 10B Cleaning member 11A, 11B Cleaner 30 Recording medium 31 Paper feed roller 32 Transport roller 33 Paper pressing plate 35 Head recovery device 36 Temperature / humidity detection member 20 Wet liquid holding part 21 Wet liquid transmission part 21a Wiper contact part 22 Rotating shaft 23 Eccentric cam 24 Rotating shaft 601 MPU
603 ASIC
604 RAM
610 Host device

Claims (14)

A recording head having an ejection port for ejecting ink, a wiper for wiping the ink ejection surface of the recording head, and wiping the ink ejection surface of the recording head by moving the wiper relative to the recording head An inkjet recording apparatus having cleaning means for performing
A reservoir for storing a processing liquid used for wiping the ink discharge surface of the recording head;
A transfer unit that contacts a part of the wiper that contacts the ink discharge surface of the recording head and transfers the processing liquid stored in the storage unit to a part of the wiper;
Detection means for detecting the temperature or humidity of the installation environment of the inkjet recording apparatus;
An ink jet recording apparatus comprising: a transfer control unit that controls a transfer amount of the processing liquid according to the temperature or humidity detected by the detection unit.   The wiper reciprocates in a predetermined direction, the transfer means is placed at an end of the reciprocation path, the ink discharge surface of the recording head is located in the middle of the reciprocation path, and the position of the transfer means 2. The inkjet according to claim 1, further comprising a cleaner that removes ink residue adhering to a part of the wiper between an ink discharge surface of the recording head and a contact position of the wiper. Recording device.   The transfer control means is a driving means for controlling the transfer amount of the processing liquid to be changed by changing a contact position of the transfer means with a part of the wiper according to the detected temperature or humidity. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is included.   The inkjet recording apparatus according to claim 3, wherein the driving unit moves the transfer unit up and down.   The ink jet recording apparatus according to claim 3, wherein the driving unit rotates the transfer unit.   The transfer control means controls to change the transfer amount of the processing liquid by changing a contact time of the transfer means with a part of the wiper according to the detected temperature or humidity. The ink jet recording apparatus according to claim 1 or 2.   The transfer control means controls to change the transfer amount of the processing liquid by changing the number of times the transfer means contacts a part of the wiper according to the detected temperature or humidity. The ink jet recording apparatus according to claim 1 or 2.   The transfer of the processing liquid is performed by moving the wiper to the position of the transfer unit every time the ink discharge surface of the recording head is wiped by the wiper. An ink jet recording apparatus according to any one of the above.   The transfer of the processing liquid is further performed by moving the wiper to the position of the transfer unit before wiping the ink discharge surface of the recording head by the wiper. Inkjet recording device. First counting means for accumulating the number of wiping operations on the ink ejection surface of the recording head;
A second counting means for accumulating the number of times the wiper is used for the wiping operation;
10. The transfer control unit according to claim 1, wherein the number of wiping operations by the cleaning unit per one wiping command is controlled according to a cumulative result of the first and second counting units. Inkjet recording apparatus.   The inkjet recording apparatus according to claim 10, further comprising an estimation unit configured to estimate a remaining amount of the processing liquid in the storage unit according to a cumulative result obtained by the second counting unit.   The inkjet recording apparatus according to claim 10, wherein the transfer control unit further controls a transfer amount of the processing liquid according to a cumulative result of the second counting unit.   The ink jet recording apparatus according to claim 1, wherein the transfer control unit controls the transfer amount of the processing liquid to be increased at a low temperature and low humidity and to be decreased at a high temperature and high humidity. A recording head having an ejection port for ejecting ink, a wiper for wiping the ink ejection surface of the recording head, and wiping the ink ejection surface of the recording head by moving the wiper relative to the recording head A head recovery method of an ink jet recording apparatus having a cleaning means
A detection step of detecting the temperature or humidity of the installation environment of the inkjet recording apparatus;
A part of the wiper that comes into contact with the ink ejection surface of the recording head abuts against a part of a storage part that stores processing liquid used for wiping the ink ejection surface of the recording head, and is stored in the storage part. A transfer step of transferring the treated liquid to a part of the wiper through the contact portion;
And a transfer control step of controlling the transfer amount of the processing liquid according to the temperature or humidity detected in the detection step.

Images