JP2019111719A - Inkjet recording device and cleaning method of the same - Google Patents

Abstract

To provide an inkjet recording device and a cleaning method of the same which can select optimum cleaning operation.SOLUTION: In an inkjet recording device that has a recording head which discharges ink through a discharge port to form an image on a roll paper and a blade which wipes out and cleans a discharge port forming face of the recording head and a blade cleaner for the blade, a CPU adjusts contact time during which liquid droplets wiped out by contacting the blade with the face is absorbed and collected, on the basis of at least either one of a recorded image by the recording head and carrying speed of the roll paper.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an ink jet recording apparatus having a function of cleaning an ink discharge port formation surface of a recording head, and a cleaning method thereof.

  The inkjet recording apparatus adopts a recording method of forming an image on a recording medium such as roll paper or cut paper by discharging ink as granular ink droplets from the discharge port of the recording head. In this inkjet recording apparatus, if a part of the ink to be discharged, dust, or the like remains attached to the formation surface of the discharge port of the recording head, the quality of the image formed on the recording medium is affected. It has a cleaning function to wipe the discharge port formation surface of the head. In addition, since leaving the wiped deposits as it is may contaminate the inside of the apparatus or contaminate the recording medium, it is also necessary to appropriately remove the wipes from the wiping member. .

  From this, Patent Document 1 describes an ink jet recording apparatus which performs an operation of removing the adhered matter wiped off from the discharge port forming surface of the recording head. It is disclosed that the ink jet recording apparatus is adjusted to an operation time according to the amount of deposit at the time of removing the deposit, in other words, the amount to be removed.

  Further, in Patent Document 2, the necessity of the cleaning operation during the recording operation in the next recording area is determined and executed, thereby avoiding the cleaning during the recording operation and preventing the deterioration of the quality of the recorded image. Inkjet recording devices are described.

JP 2011-136466 A JP 2001-121717 A

  However, the ink droplets discharged by the recording head of such an ink jet recording apparatus contain water and the like as well as the pigment and dye for color formation. From this, for example, the attached matter adhering to the discharge port formation surface of the recording head is often present in a state of being evaporated by adhering from the state of being discharged onto the recording medium, and when it is left under this condition. The water evaporates again and the viscosity rises.

  For this reason, in the conventional ink jet recording apparatus, the operation time is adjusted according to the removal amount of the deposit adhering to the discharge port forming surface of the recording head. From this, the time of the cleaning operation required to remove the viscosity-increased deposit is set. Therefore, for example, in the case of an attached substance having a large amount of water, the problem that the operation time is wasted and the throughput is reduced despite the fact that the cleaning operation can be completed in a short time It turned out by research and development.

  An object of the present invention is to provide an ink jet recording apparatus capable of selecting an optimum cleaning operation and a cleaning method thereof in view of such a problem.

One aspect of the invention of an inkjet recording apparatus for solving the above problems is a recording head for ejecting ink from an ejection port to form an image on a recording medium, and a cleaning means for wiping and cleaning the surface of the recording head on which the ejection port is formed. And control means for controlling a cleaning operation of wiping the object to be wiped from the discharge port formation surface of the recording head by the cleaning means based on at least one of the recording image formed by the recording head and the conveyance speed of the recording medium , And is characterized in that

  One aspect of the invention of a cleaning method for an ink jet recording apparatus that solves the above problems is a recording head that discharges ink from a discharge port to form an image on a recording medium, and cleaning by wiping the formation surface of the discharge port of the recording head. Cleaning method in an inkjet recording apparatus having at least one of a recording image formed by the recording head and a conveyance speed of the recording medium, and the cleaning method of the cleaning unit is performed based on the acquired information. It is characterized in that the cleaning operation is controlled.

  As described above, according to one aspect of the present invention, it is possible to provide an inkjet recording apparatus capable of selecting an optimal cleaning operation and a cleaning method therefor.

FIG. 1 is a schematic configuration view showing an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a conceptual view showing the arrangement of the main part configuration. FIG. 3 is an elevation view seen from one direction showing the positional relationship of the main part configuration. FIG. 4 is a block diagram showing the control system. FIG. 5 is a partially enlarged conceptual view for explaining formation of the material to be wiped in time series. FIG. 6 is a flow chart for explaining the cleaning method of the material to be wiped. FIG. 7 is a flow chart for explaining the main part of the method of cleaning the object to be wiped shown in FIG. FIG. 8 is a list showing the cleaning conditions to be adjusted together with the properties of the material to be wiped. FIG. 9 is an elevation view seen from one direction showing the positional relationship of the main part configuration of another embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 8 are diagrams for explaining a printer as an example of an ink jet printing apparatus according to an embodiment of the present invention and a cleaning method thereof, and FIG. 1 is for explaining the overall configuration of an image printing system including the printer. It is a conceptual block diagram.

  In FIG. 1, a printer 100 is a recording apparatus which forms and prints an image by an ink jet recording method using roll paper P wound in a roll shape as a recording medium. The printer 100 is connected by a printer cable C so that a PC (Personal Computer) can exchange various information as a host device H of the information processing apparatus. The host device H outputs, to the printer 100 via the printer cable C, image data, various information such as the paper width related to the roll paper P, and the cutting position (size designation) of the roll paper P as a control command.

  The printer 100 discharges each color ink from the discharge port 132 of the recording head 131 onto the roll paper P at the image forming position based on the image data and the like received from the host device H, and after recording and forming an image, Disconnect. Here, in the present embodiment, the roll-shaped roll paper P is described as an example of the recording medium, but the present invention is not limited to this. For example, other forms such as cut paper having been cut into a predetermined size It may be. Needless to say, the present invention may be applied to a printer that forms an image on a recording medium other than paper.

  In the printer 100, image data received from the host apparatus H is recorded and formed on the transported roll paper P as the control unit (controller) 150 centrally controls the apparatus units such as the paper unit 110 and the recording unit 130.

  The sheet unit 110 is constructed by arranging the sheet conveying device 111 and the sheet cutting device 121.

  The sheet conveyance device 111 includes a conveyance belt 112 and a suction fan 118 housed in a case 119. Conveying belt 112 is endlessly rotatable (seamlessly) around a drive roller 115a integral with a rotation shaft of conveyance motor 115 together with guide roller group 113 (113a to 111c) in a state where a part is exposed on the upper surface side of case 119. It has been passed. In the conveyance belt 112, suction holes (not shown) are opened at a plurality of locations continuous in the conveyance direction of the roll paper P. The suction fan 118 is installed to exhaust the air in the case 119 from the exhaust port 119a to the outside.

  As a result, the sheet conveyance device 111 can adsorb the roll sheet P through the suction holes of the conveyance belt 112 by exhausting the inside of the case 119 with the suction fan 118 to make it under negative pressure. The sheet conveyance device 111 moves the conveyance belt 112 on which the roll sheet P is adsorbed in the horizontal conveyance direction A indicated by the arrow A in FIG. 1 to pull out the roll sheet P and cut it by the sheet cutting device 121. The sheet can be discharged out of the apparatus via the position.

  Here, the roller group 113 is configured such that the pair of guide rollers 113 a and 113 b are disposed at the upstream end and the downstream end of the roll paper P in the transport direction A of the upper surface of the case 119 to wind the transport belt 112. In the horizontal direction parallel to the top surface of the case 119. Further, the guide roller 113c functions as a pulley that urges the tension of the conveyance belt 112 wound around the drive roller 115a of the conveyance motor 115 not to be loosened. Further, pressing rollers 114a and 114b are disposed at the drawing-out portion of the roll paper P and the suction start position to the conveyance belt 112, and support for smoothly feeding and conveying the drawn roll paper P onto the conveyance belt 112 It is supposed to be.

  The sheet cutting device 121 is configured to include a rotary blade 122, a fixed blade 123, and a stopper 124. The paper cutting device 121 cuts the roll paper P located between the fixed blade 123 and the fixed blade 123 by rotating the rotary blade 122 in the direction of arrow B in FIG. 1 at a predetermined timing. The sheet cutting device 121 restricts or allows the rotation of the rotary blade 122 by moving the stopper 124 in the direction of the arrow C in FIG.

  In the sheet unit 110, detection sensors 127a, 127b, and 127c for detecting the roll paper P are disposed in the middle of the conveyance path, and an encoder 128 for detecting the rotation of the guide roller 113c is disposed. It is connected to the. Among these, the detection sensor 127a is disposed between the pressing rollers 114a and 114b, and detects the presence or absence of the roll paper P to be pulled out. The detection sensor 127 b is disposed on the upstream side of the recording unit 130 described later, and detects the leading end of the roll paper P being pulled out. The detection sensor 127c is disposed on the upstream side of the sheet cutting device 121, and detects the leading edge of the roll paper P being delivered. The encoder 128 detects the rotation of the guide roller 113 c to obtain the movement amount of the conveyance belt 112. Thereby, the control unit 150 can realize optimization of the image forming position by the recording unit 130 and the cutting position by the sheet cutting device 121 based on the detection information of the sensors 127a, 127b, 128.

  Here, the detection sensors 127a, 127b, and 127c detect the leading end of the roll paper P with a structure provided with one or both of a reflection type and a transmission type. For example, when the roll paper P is a recording sheet on which an image is formed for each predetermined area and cut, and the image formation area is marked so as to be detectable, a difference in light reflectance due to the mark The upstream end of the image forming area to be the tip can be detected based on the above. Also, for example, when the roll paper P is a label sheet, the upstream end of the label as the leading edge is detected based on the difference in transmittance between the backing sheet and the label attached to the backing sheet. Can. As other sensors connected to the control unit 150, various sensors such as sensors for detecting the temperature and humidity of the surrounding environment are connected.

  As shown in FIG. 2, the recording unit 130 is configured to include a recording head 131, a cap 133, a blade 134, a blade cleaner 135, an ink cartridge 141, and a waste ink tank 143.

  The recording head 131 adopts an ink jet recording method, and discharges the ink in the internal storage tank 131 t toward the roll paper P conveyed by the paper unit 110 to form an image. The recording head 131 maintains the quality of the ejected ink constant by the ink cartridge 141 and the waste ink tank 143, and keeps the portion of the recording head 131 facing the roll paper P clean by a blade 134 or the like.

  The recording head 131 is installed such that the lower surface facing the transported roll paper P is the formation surface 131 a of the ink discharge port (nozzle) 132. The recording head 131 executes a recording operation for forming an image on the roll paper P by discharging granular ink, that is, ink droplets from the discharge port 132 in a state where the nozzle forming surface 131a faces the roll paper P in close proximity. Do.

  Further, in the recording head 131, a plurality of ink discharge ports (nozzles) 132 are formed so as to align the paper width direction orthogonal to the transport direction A of the roll paper P as the main scanning direction. That is, the recording head 131 is formed in a so-called elongated form of a full line head which covers the full width of the roll paper P as an image forming area.

  Here, the recording head 131 discharges the electrothermal conversion element (heater 131 h shown in FIG. 5) installed in the ink flow path communicating with the discharge port 132 by generating an air bubble instantaneously to discharge the air. A so-called thermal method in which ink droplets are discharged from the outlet 132 is adopted. The recording head 131 is not limited to the thermal method. For example, a piezoelectric element (piezo element) for instantaneously changing the capacity of the ink flow path is installed, and a so-called piezoelectric method for discharging ink droplets from the discharge port 132 It goes without saying that it may be adopted.

  Further, as shown in FIG. 3, the recording head 131 has separate recording heads 131Y, 131M, 131C, and 131K for each color ink of yellow (Y), magenta (M), cyan (C) and black (K). Have. The recording heads 131Y, 131M, 131C, and 131K are juxtaposed so as to line up sequentially from the upstream side to the downstream side in the transport direction A of the roll paper P. As a result, the recording head 131 discharges the yellow (Y), magenta (M), cyan (C), and black (K) color inks in accordance with the conveyance of the roll paper P, and overlaps the one side of the label. A full color recorded image can be formed.

  The recording head 131 includes a cap 133, a blade 134, and a blade cleaner 135. The cap 133 is attached and detached so as to cover the nozzle forming surface 131 a in which the discharge port 132 is formed. The blade 134 is cleaned by wiping its nozzle forming surface 131a to remove deposits and the like. The blade cleaner 135 recovers and cleans the remaining deposit by absorbing the remaining contact by contacting the blade 134. That is, the blade 134 functions as a cleaning unit that wipes and cleans the deposit on the nozzle forming surface 131a of the recording head 131 as a wipe and is equipped with a blade cleaner 135 that recovers the deposit from the blade 134 as a recovery unit. ing.

  In detail, the cap 133 is movably supported separately from the recording head 131. The cap 133 is moved to a position facing the nozzle forming surface 131 a of the recording head 131 and is detachably installed. The cap 133 is attached to the nozzle forming surface 131 a of the recording head 131 to form a sealed space on the nozzle forming surface 131 a side of the discharge port 132.

  Thus, the cap 133 can prevent the promotion of the useless adhesion and the drying of the ink as much as possible by blocking the nozzle formation surface 131a of the recording head 131 from the outside air. The cap 133 may be disposed on each of the recording heads 131Y, 131M, 131C, and 131K, and may be disposed to cover the side of the nozzle formation surface 131a in which the ejection openings 132 for the respective color inks are opened.

  The blade 134 is movably supported integrally with the cap 133. The blade 134 is moved to a position where the end side 134 a is in contact with the nozzle forming surface 131 a of the recording head 131 to maintain the contact state, and is positive in the direction parallel to the forming line of the discharge ports 132 (arrow D direction in FIG. It is installed so that reverse movement is possible. In short, the blade 134 moves integrally with the cap 133 which moves in the forward and reverse directions in the direction D parallel to the formation line of the discharge ports 132 of the recording head 131. In the blade 134, the end side 134a side of the posture orthogonal to the formation row of the discharge ports 132 of the recording head 131 contacts and moves the entire surface in the longitudinal direction of the nozzle formation surface 131a to attach residual ink etc. on the nozzle formation surface 131a. It is made of plate material to wipe the kimono. For example, the blade 134 is made of a rubber plate so that the nozzle formation surface 131a of the recording head 131 can be effectively wiped (wiping). The blade 134 is disposed so as to cover the entire nozzle formation surface 131 a of each color ink of the recording heads 131 Y, 131 M, 131 C, and 131 K.

  As a result, the blade 134 can keep the nozzle formation surface 131a of the recording head 131 clean, and it is possible to prevent the adhered matter such as the residual ink from being rubbed against the roll paper P and thereby becoming dirty. The blade 134 is not only formed into a shape that allows wiping of a plurality of recording heads 131 as in the present embodiment, but also, for example, one for each recording head 131 in the formation row of the discharge ports 132. It may be installed in an orthogonal or oblique attitude. Furthermore, in the present embodiment, the lower surface of the recording head 131 is described as the nozzle forming surface 131a on which the ejection ports 132 are formed, and the single blade 134 wipes the entire surface, but the present invention is not limited thereto. For example, the nozzle forming surface 131 a of the recording head 131 is divided into a peripheral edge (so-called, discharge port surface) near the discharge port 132 and an outer peripheral edge (so-called face surface) not including the peripheral edge near the discharge port 132. It is also possible to wipe each with a separate blade.

  The blade cleaner 135 is installed at a contact position where the end side 134 a side of the blade 134 whose wiping of the deposit has been finished abuts at the end side end of the nozzle forming surface 131 a where the blade 134 of the recording head 131 contacts and moves. . The blade cleaner 135 scrapes off the deposit remaining on the blade 134 wiped away from the nozzle forming surface 131 a of the recording head 131 and transfers it and absorbs the liquid material contained in the deposit. It has become. The blade cleaner 135 is made of a hard porous material capable of efficiently absorbing the liquid contained in the deposit remaining on the blade 134. In the same manner as the blade 134, the blade cleaner 135 may be provided with a plurality of blades 134 or a single blade 134 with respect to the plurality of blades 134. Further, the blade cleaner 135 is not limited to a hard porous material, and may be made of a liquid absorbent material such as a non-woven fabric.

  Here, after the cap 133 and the blade 134 are moved from the facing position with the nozzle forming surface 131 a of the recording head 131 and moved from the retracted position not obstructing the discharge of the ink to the abutting contact position with the blade cleaner 135, Wait at a position beyond the collection position.

  In the recording head 131, the ink cartridge 141 and the waste ink tank 143 are connected to each other through the tubes T1 and T2. An open / close valve 142 is installed in the tube T1, and the open / close valve 142 enables the recording head 131 and the storage tanks 131t and 141t of the ink cartridge 141 to be switched to the communication state or the blocking state. A pump 144 capable of forward and reverse drive is installed in the tube T2, and the inside of the storage tank 131t of the recording head 131 can be switched to the reduced pressure state or the pressurized state. The ink cartridge 141 is prepared for each color ink of yellow (Y), magenta (M), cyan (C) and black (K), and is connected to the separate recording head 131. Further, since the waste ink tank 143 does not have to be divided into each color ink, the waste ink tank 143 may be made switchable by installing a switching valve (not shown) at the front stage of the pump 144.

  As a result, in the recording head 131, the inside of the storage tank 131t becomes negative pressure by the discharge of the ink in a state where the on-off valve 142 is opened, whereby the ink is replenished from the inside of the ink cartridge 141 (storage tank 141t). Further, the recording head 131 causes the pump 144 to perform suction operation with the open / close valve 142 opened, and the inside of the ink cartridge 141 is filled with ink by depressurizing the inside of the storage tank 131 t. On the other hand, the recording head 131 causes the pump 144 to perform the discharge operation in a state where the on-off valve 142 is closed, and the inside of the storage tank 131t is pressurized, thereby discharging the ink in the discharge port 132 and refreshing. At this time, for example, the ink whose viscosity has been raised by waiting in the discharge port 132 of the recording head 131 may be discharged into the sealed space of the cap 133 attached to the nozzle forming surface 131a. The discharge process of the ink with the increased viscosity can be preliminarily performed before starting the image forming process to maintain the quality of the recorded image with high reliability. The waste ink discharged into the sealed space of the cap 133 may be sucked by the pump 144 through a tube (not shown) and discharged into the waste ink tank 143 or the like.

  As shown in FIG. 4, the control unit 150 records and forms image data received from the host apparatus H on the roll paper P by central control of the entire printer 100 by a central processing unit (CPU) 151. A controller group of an interface (I / F) controller 153, a recording head control circuit 154, and a motor drive unit 155 is connected to the CPU 151 such that various information can be communicated. A control panel 159, a sensor group 129 such as a detection sensor 127 (127a, 127b, 127c), and an encoder 128 are connected to the CPU 151 such that various information can be communicated. A memory group of a program ROM (Read Only Memory) 161, a work RAM (Random Access Memory) 163, and an image memory 165 is connected to the CPU 151 so that various types of information can be exchanged. The CPU 151 controls the operation of each connected device based on various input information input from the operation panel 159 together with control commands including image data received from the host device H.

  Here, the I / F controller 153 executes various types of communication control with the CPU 151 and connects the host apparatus H with various data such as control commands so as to be exchangeable. The recording head 131 for each color ink is connected to the recording head control circuit 154, and controls an operation of discharging the ink from the discharge port 132 of the corresponding recording head 131 based on a drive instruction received from the CPU 151. The motor drive unit 155 is connected to various drive motors described later including the transport motor 115, and adjusts the power supply to the corresponding transport motor 115 etc. based on the drive instruction received from the CPU 151 to control the drive.

  In addition to the transport motor 115, the head drive motor 171, the cap motor 173, the pump motor 175, the valve drive motor 177, and other drive motors are connected to the motor drive unit 155 so as to supply or cut off drive current. It is done. The conveyance motor 115 rotates the drive roller 115 a forward and reverse to output a driving force to rotate the conveyance belt 112. The head elevating motor 171 outputs motive power for moving the recording head 131 to the position facing the roll paper P and the mounting position of the cap 133. The cap motor 173 outputs power to move the cap 133 to the mounting position of the recording head 131 on the nozzle forming surface 131 a. The pump motor 175 outputs a driving force for driving the pump 144 in forward and reverse directions. The valve drive motor 177 outputs a drive force for switching between the open state and the closed state of the on-off valve 142. As the other driving motor, for example, a driving force for rotating the fixed blade 123 or the like is output. The CPU 151 may directly control the drive of another drive unit such as the stopper 124 or may control the drive of the motor drive unit 155 or another drive control unit.

  The program ROM 161 prestores various processing programs such as a control program for overall control of the printer 100 and various parameters used in the processing programs. The work RAM 163 is used as a work area when the CPU 151 executes a processing program. In the image memory 165, image data for each color of image data created based on the analysis result of the control command received by the CPU 151 is bitmapped.

  As the sensor group, in addition to the detection sensor 127 for the roll paper P and the encoder 128 for acquiring the rotation of the guide roller 113c, the temperature sensor for detecting the temperature around the recording head 131 can receive sensor information from the CPU 151 It is connected to the.

  Then, the CPU 151 executes the control program stored in the program ROM 161 while using the work RAM 163, thereby integrally controlling the entire printer 100 such as the drive unit group based on sensor information detected by the detection sensor 127 or the like. . As a result, the CPU 151 develops the image data received from the connected host device H into a bit map for each color in the image memory 165, controls the drive of the print head control circuit 154, etc., and transfers it to the print head 131. Image formation on roll paper P. Further, the CPU 151 receives a control command such as a position at which the roll paper P on which the image is formed is cut together with the image data, and controls the motor drive unit 155 to convey the roll paper P to the image forming position to form an image. After cutting, it is cut to the desired size and discharged.

  At this time, when receiving a control command including image data, the CPU 151 analyzes the total number of dots, and also refers to the number of dots per unit area and the ink such as the number of dots per unit time with reference to the transport speed of the roll paper P. Analyze and calculate the discharge condition of. The CPU 151 executes a cleaning operation for cleaning the nozzle formation surface 131 a and the like of the recording head 131 and a recovery operation for recovering the ink quality in the ejection port 132 at a preset timing.

  Specifically, the CPU 151 moves the recording head 131 and the cap 133 appropriately and attaches the cap 133 to the nozzle forming surface 131 a of the recording head 131 to perform an operation of shielding from the open air and maintaining the cleanliness Do. Further, the CPU 151 executes an operation of cleaning by wiping the nozzle forming surface 131 a of the recording head 131 with a blade 134 integral with the cap 133. Further, the CPU 151 recovers the quality by preliminary discharging the ink in the discharge port 132 before the image forming process on the roll paper P while the cap 133 is attached to the nozzle forming surface 131a of the recording head 131. Execute the action. In the cleaning process, the CPU 151 wipes the nozzle formation surface 131a of the recording head 131 with the blade 134 and then discharges a small amount of ink from the discharge port 132 in advance to adjust the meniscus of the ink. Further, when the predetermined amount of the predischarged ink is stored, the CPU 151 sucks by the pump 144, discharges it to the waste ink tank 143, and discards it.

  In the printer 100, as shown in FIG. 5A, when the ink droplet Ig discharged from the discharge port 132 of the recording head 131 reaches the roll paper P (so-called landing) and forms an image, Components such as water mainly contained in the ink I evaporate from the surface of the roll paper P. As shown in FIG. 5B, the evaporation component ascends and adheres to the nozzle forming surface 131a of the recording head 131 facing the image forming surface of the roll paper P, condenses, and condenses. Then, as shown in FIG. 5C, the evaporation component adhering to the nozzle formation surface 131a of the recording head 131 condenses and condenses, thereby forming a droplet Id of the object to be wiped by the blade 134, and the blade cleaner 135 Be collected When the printing operation of the printer 100 is continued, the droplet Id also increases in size, that is, the amount of liquid. The liquid amount of the droplets Id changes in accordance with the total number of dots for image formation, the number of dots per unit area, or the number of dots per unit time (period) during image formation. Therefore, the liquid amount of the droplet Id is calculated and estimated using, for example, a cleaning count described later which is counted to determine the cleaning timing, and the ratio of the contained condensation component is also described later. It can be calculated and estimated using it. In addition, not only the evaporation component (condensed component) of the ink I, but also foreign matter such as paper dust generated at the time of conveyance of the roll paper P is mixed into the droplet Id on the nozzle formation surface 131a of the recording head 131. It is a kimono (to be wiped).

  From this, the CPU 151 estimates and acquires the characteristic information of the droplet Id from the cleaning count acquired as cleaning information to determine the necessity of the specified cleaning operation of the nozzle forming surface 131a of the recording head 131, and a series of cleaning operations Execute control processing of (cleaning method). That is, the CPU 151 constitutes the control means together with the acquisition means.

  In detail, the CPU 151 performs control processing for executing the various operations described above based on the control program. At this time, the CPU 151 collects and acquires various information and performs an optimal operation under an optimal condition. It is supposed to run.

  The CPU 151, for example, estimates and acquires information on the proportion of the condensed component contained in the droplets Id of the nozzle formation surface 131a of the recording head 131 as described later, and controls the cleaning operation by the blade 134 and the blade cleaner 135. The CPU 151 controls the contact time (cleaning operation) between the blade 134 and the blade cleaner 135 based on the acquired information of the droplet Id, and the absorption (recovery) time by the blade cleaner 135 of the droplet Id adhering to the blade 134 Is supposed to adjust.

  At this time, for each printing operation (within a predetermined period) in which the image data is recorded and formed on one page of the roll paper P, the CPU 151 is based on the ink ejection amount (integrated value of the total number of printing dots) according to the image data. Thus, the ratio information of the condensed component of the droplet Id is estimated and acquired. The CPU 151 collects the droplet Id adhering to the blade 134 by the blade cleaner 135 when the ratio information of the condensed component of the droplet Id exceeds a threshold (ratio threshold) Nth set in advance in the program ROM 161. Reduce time. For example, to shorten the recovery time, the information on the ratio of the condensation component of the droplet Id is set to be several times smaller than the recovery time in the normal operation when the threshold Nth is not exceeded.

  Then, as shown in FIG. 6, when the CPU 151 receives image data to be printed from the host device H (step S11), it starts print control processing for recording the image data on the roll paper P page by page (step S11). Step S12). Next, the CPU 151 counts the number of ejections of the ink droplet Ig ejected from the ejection port 132 of the print head 131 during printing (the number of dots on which image data is printed and formed) along with the print control processing. The process is started (step S13).

  Next, the CPU 151 repeatedly checks whether or not recording formation of image data for one page is completed (step S14), and after completion confirmation, the count exceeds the cleaning threshold Cth for cleaning necessity determination which is set in advance. It is confirmed whether or not it is (step S15). That is, the CPU 151 uses the count as a cleaning count which is counted to determine the cleaning timing.

  The CPU 151 confirms that the count of the number of ejected ink droplets Ig (total number of dots) in step S15 does not exceed the cleaning threshold Cth, and further determines whether printing of the image data received from the host device H is completed. It confirms (step S19).

  Having confirmed that printing of the image data of the host apparatus H is not completed in step S19, the CPU 151 returns to step S14 and repeats the same process of printing the image data of the next page. On the other hand, the CPU 151 that has confirmed the end of printing of the image data of the host apparatus H in step S19 executes control processing including a series of cleaning operations and the like for ending this printing.

  Here, the cleaning threshold value Cth for cleaning necessity determination is tested with an actual machine, and cleaning is performed before occurrence of inconvenience regardless of the liquid quality described later of the droplet Id adhering to the nozzle forming surface 131a of the recording head 131. It should be a value to start the operation. For example, if a standard value of the total number of dots (the number of discharges) at which the droplet Id contacts the roll paper P and is soiled is determined, and set appropriately to 2/3 or half thereof. Good.

  In step S15, the CPU 151 confirms that the count exceeds the cleaning threshold Cth. First, it estimates and acquires component information of the droplets Id adhering to the nozzle forming surface 131a of the recording head 131 during image recording on the roll paper P. Processing is performed (step S16).

  Thereafter, the CPU 151 starts control processing of the cleaning operation described later (step S17), clears the count (step S18), proceeds to step S19, and continues or ends the print control processing.

At this time, component information of the droplets Id (adhered matter) attached to and formed on the nozzle formation surface 131a of the recording head 131 is estimated and obtained by calculating for each page of the roll paper P using the following equation can do.
Component information Ci of droplet Id = total printing dot number × 1 page length / conveyance speed of roll paper P

  The “total printing dot number” in the equation can be regarded as a parameter corresponding to the total amount of ink droplets Ig used in image recording. Also, “one page length / conveying speed of roll paper P” is a printing time required to record an image of one page.

  By the way, water or the like evaporated from the ink droplet Ig for image recording on the roll paper P adheres to the nozzle forming surface 131a of the recording head 131 to condense and condense, thereby forming a droplet Id. Small amounts of dust such as paper dust of P and pigments of ink droplets Ig are also contained.

  From this, in the “component information Ci of the droplet Id” as the calculation result of the above equation, the moisture and the like of the droplet Id adhering to the nozzle formation surface 131a of the recording head 131 changes depending on the printing time. It can be acquired as a parameter of time.

  The component information Ci of the droplet Id is a liquid of an easily absorbing component having a large proportion of water etc. when the recording image having a large number of total printing dots is formed on the roll paper P transported at high speed in a short time. It is a parameter indicating that it is quality. On the other hand, when forming a recorded image with a small number of total printing dots on a low speed conveying roll paper P over a long period of time, the droplet Id is a liquid of a difficult-to-absorb component which is thickened etc. It is a parameter that indicates that there is.

  Here, in the present embodiment, the case where the component information Ci of the droplet Id is calculated without distinction for the ink color of the recording head 131 will be described as an example. However, the present invention is not limited to this. Weighting may be performed according to the difference in water content and the like.

  Then, as shown in FIG. 7, the CPU 151 that has started the control processing of the cleaning operation at step S17 has exceeded the threshold (proportional threshold) Nth set in advance for the component information Ci of the droplet Id acquired at step S16. It is confirmed whether or not it is (step S21).

  The CPU 151 confirms that the component information Ci of the droplet Id exceeds the threshold value Nth in this step S21, brings the blade cleaner 135 into contact with the blade 134 and sets the collection time of the droplet Id adhering to the adjustment time A. (Step S22). Next, the CPU 151 executes the cleaning operation A for wiping the adhering matter such as the droplets Id adhering to the nozzle forming surface 131a of the recording head 131 by the blade 134 (step S23), and returns to step S18 in FIG. At this time, the adjustment time A set as the collection time of the droplet Id by the CPU 151 is set, for example, as 0.3 second described later as the adjustment collection time so that the optimum collection operation can be performed. In this cleaning operation A, for example, the water contained in the ink droplet Ig is evaporated and there is a large amount of condensed components condensed, so the adhering droplets Id are mostly evaporation components such as water, and the blade 134 to the blade cleaner 135 Absorbed and recovered in a short time. In the cleaning operation A, not only the recovery time is shortened to the adjustment time A, but the wiping operation by the blade 134 may be simplified as compared with the cleaning operation B at the normal time.

  On the other hand, the CPU 151 confirms that the component information Ci of the droplet Id does not exceed the threshold Nth in step S21, brings the blade cleaner 135 into contact with the blade 134 and collects the droplet Id collected for the normal specified time B. It sets (step S24). Next, the CPU 151 executes a normal cleaning operation B to wipe off the deposits such as the droplets Id adhering to the nozzle formation surface 131a of the recording head 131 by the blade 134 (step S25), and returns to step S18 in FIG. . At this time, for the specified time B set by the CPU 151 as the collection time of the droplet Id, for example, 2 seconds described later is set as the specified collection time so that an optimum collection operation can be performed.

By the way, the time of absorption removal (collection) of droplet Id by blade cleaner 135 can be computed using the following formula of Lucus-Washburn.
L = ((d × t × γ × cos θ) / 2η) ^1/2
L: penetration distance, d: capillary radius, t: penetration time, γ: surface tension, θ: contact angle, η: viscosity

  The droplets Id of the component information Ci exceeding the threshold Nth and the droplets Id of the component information Ci below the threshold Nth have, for example, the characteristics shown in FIG. In the droplet Id of the component information Ci exceeding the threshold Nth, from the characteristics that the surface tension γ is high and the viscosity が is low, the absorption of the blade cleaner 135 takes 2 seconds if the threshold Nth or less. It can absorb in a short time of 3 seconds. The absorption of the droplets Id by the blade cleaner 135 can be adjusted to some extent by appropriately setting the material of the used material, the capillary, the contact angle, and the like.

  Therefore, the threshold Nth to be compared with the component information Ci of the droplet Id may be appropriately set by deriving using the above equation according to the blade cleaner 135 provided in the recording head 131 of the printer 100.

  In addition, the threshold value Nth may be set to a collection time according to the liquid quality of the droplet Id adhering to the nozzle formation surface 131 a of the recording head 131 by performing various image recording tests. In this case, not only whether the threshold value Nth is exceeded, but also a map indicating the correspondence characteristic between the component information Ci of the droplet Id and the recovery time is created, etc., and proportional calculation etc. are appropriately set. May be

  As described above, in the CPU 151 of the present embodiment, the contact of the blade cleaner 135 with the blade 134 based on the component information Ci according to the ratio information of the condensation component of the droplet Id adhering to the nozzle forming surface 131a of the recording head 131 Adjust the (recovery) time.

  For this reason, the cleaning operation can be completed quickly with the optimal recovery time according to the ratio of the condensed component contained in the droplet Id, and the image quality of the splitter image can be reduced without a drop in throughput due to the efficient and effective cleaning. Can be maintained.

In the present embodiment, the contact (recovery) time of the blade cleaner 135 with the blade 134 is adjusted based on the component information Ci of the droplet Id, but the blade 134 is adjusted based on the number of dots of the recorded image or the conveyance speed. The contact (recovery) time of the blade cleaner 135 may be adjusted.
That is, when the number of dots of the recorded image is large, the contact time between the blade 134 and the blade cleaner 135 is shortened as compared with the small number, or when the conveyance speed at the time of image recording is high, compared with the low time. By shortening the contact time between the blade 134 and the blade cleaner 135, the effect of the present invention can be obtained.

  Here, in the above-described embodiment, the blade 134 is disposed to be orthogonal to the formation row of the discharge ports 132 of the recording head 131, but the present invention is not limited to this. For example, as shown in FIG. 9, the blade 234 parallel to the formation row of the discharge ports 132 is installed on the cap 233 and moved in the arrow direction E in FIG. 9 orthogonal to the formation row. Good. Also in this case, the droplets Id on the nozzle forming surface 131a can be wiped off by the blade 234, and the droplets Id can be absorbed and collected by the blade cleaner 235. At this time, the stroke for moving the blade 234 can be shortened, and the throughput of the cleaning operation can be further shortened.

  While embodiments of the present invention have been disclosed, it will be apparent to one skilled in the art that modifications can be made without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

100 ... printer 110 ... sheet unit 111 ... sheet conveying device 112 ... conveying belt 118 ... suction fan 121 ... sheet cutting device 130 ... recording unit 131, 131Y, 131M, 131C, 131K ... recording head 131a ......... Nozzle formation surface 132 ... Discharge port 133, 233 ... Cap 134, 234 ... Blade 135, 235 ... Blade cleaner 141 ... Ink cartridge 142 ... On-off valve 143 ... Waste ink tank 144 ... Pump 150 ...... Control unit 151 ... CPU
H: host device I: ink Id: droplet Ig: ink droplet P: roll paper

Claims (5)

A recording head configured to form an image on a recording medium by discharging ink from a discharge port;
A cleaning unit that wipes and cleans the surface of the recording head on which the discharge port is formed;
A control unit configured to control a cleaning operation of wiping the object to be wiped from the discharge port forming surface of the recording head by the cleaning unit based on at least one of the recording image formed by the recording head and the conveyance speed of the recording medium;
An inkjet recording apparatus comprising:   The inkjet recording apparatus according to claim 1, wherein the control unit controls the cleaning unit on the basis of an amount by which the ink is ejected within a predetermined period. The cleaning unit includes a blade that wipes the discharge port forming surface of the recording head, and a recovery unit that contacts the blade to absorb and recover the material to be wiped.
2. The apparatus according to claim 1, wherein the control means adjusts a contact time of the collection means with the blade according to at least one of an image to be recorded and a conveyance speed of the recording medium. The inkjet recording device according to Item 2.   The control means determines the proportion of the condensed component contained in the material to be wiped based on at least one of the recorded image and the transport speed, and the proportion of the condensed component exceeds a preset threshold value. 4. The ink jet printing apparatus according to claim 3, wherein the contact time of the recovery means with the blade is shorter than that in the case where the threshold is not exceeded. A cleaning method for an ink jet recording apparatus, comprising: a recording head configured to form an image on a recording medium by discharging ink from a discharge port; and cleaning means configured to wipe the surface of the recording head on which the discharge port is formed.
An inkjet recording apparatus, comprising: acquiring at least one of a recording image formed by the recording head and a conveyance speed of the recording medium, and controlling a cleaning operation of the cleaning unit based on the acquired information.

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