JP2010005850A - Method detecting full-up state and inkjet image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for detecting a full-up state capable of preventing erroneous detection. <P>SOLUTION: When a full-up state is detected (when it is preliminarily determined that the inside of a cap 62 is full of ink), a defoaming operation for removing bubbles in the cap 62 is first performed in order to determine whether or not bubbles are generated in the cap 62. The defoaming operation is performed in such a manner that the cap 62 is left as it is for a predetermined time period (e.g., 20 seconds) (S1102), and then a suction pump 204 is operated for a predetermined time period (e.g., 5 seconds) so as to suck ink from the cap 62 (S1103). After the sucking operation is completed, it is determined again whether or not the cap 62 is full of ink (S1104). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a full tank detection method for detecting whether or not a cap that receives ink discharged from a recording head is full with ink, and an ink jet image forming apparatus that executes this method.

  A recording head having an ink discharge port forming surface (face surface) on which a plurality of ink discharge ports for discharging ink (ink droplets) are formed, and ink is selectively discharged onto a recording medium from the plurality of ink discharge ports. An ink jet type image forming apparatus (ink jet recording apparatus) for forming a film is widely known. In this ink jet type image forming apparatus, thickened ink and dust may accumulate around the nozzles and ink discharge ports of the recording head and bubbles may accumulate in the liquid chamber of the recording head during recording and standby. In such a case, problems such as ink ejection failure and recording disturbance occur. In order to solve such problems, in an ink jet recording apparatus, ink in a recording head is forcibly discharged to remove bubbles accumulated in the recording head, thickened ink attached to the face surface, and dust. An operation (recovery operation) of wiping the face surface with a wiper blade made of an elastic body is known. In particular, in a long head, a mechanism for discharging ink by pressure recovery is often used to discharge bubbles in the liquid chamber of the recording head. In the technology of discharging ink from the recording head by pressure recovery and discharging bubbles in the liquid chamber of the recording head, the amount of ink discharged from the recording head increases, and when the discharged ink is used as waste ink, Ink is wasted and running costs are high. Therefore, there is a method in which the ink once discharged from the recording head to the rubber cap is returned to the sub tank by a pump through a filter, and is sent to the recording head for reuse (reuse).

  However, when the ink discharged from the recording head is reused through a filter, the filter may be clogged with dust or thickened ink, and the ink flow path resistance may increase. When the flow path resistance increases in this way, the flow rate per unit time of the ink recycled from the cap to the sub tank or the like by the suction pump decreases. In the worst case, the amount of waste ink discharged from the recording head per unit time may exceed the amount of ink recycled per unit time, and the ink may leak out from the rubber cap. In addition, the inside of the cap is filled with bubbles (bubbles) that are generated in the recording head or in the middle of the ink flow path and are forcibly discharged to the cap, and bubbles are generated in the cap. It may leak out. Furthermore, ink may leak from the rubber cap due to a failure of the suction pump itself.

  In order to solve the above problems, a pressure switch or pressure sensor is installed downstream of the filter, and the detected pressure prevents clogging of the filter and pump failure to prevent ink and bubbles from leaking from the cap. The structure which performs is known (refer 1st solution, for example, patent document 1).

In addition, if a detection sensor using electrodes is placed in the cap and the ink level is detected by this detection sensor, it is detected that the cap is full of ink or bubbles. Is known, and the apparatus is stopped (see second solution, for example, Patent Document 2).
JP 2000-015836 A JP 2006-264205 A

  However, since the first solution described above is configured to prevent ink leakage using pressure as a trigger, there are many false detections, and detection of bubbles accumulated in the cap is virtually impossible.

  In the second solution described above, since the ink and bubbles in the cap are directly detected, the detection accuracy is good. By the way, causes (factors) for detecting an ink full in the cap and generating an error include a decrease in the ink suction amount due to clogging of the filter and a malfunction of the suction pump. When the ink in the cap becomes full due to such a cause, the ink leaks from the cap. Therefore, it is necessary to generate an error, stop the apparatus, and receive maintenance work by a service person or the like.

  However, even when the inside of the cap is filled with bubbles that are generated in the recording head or in the middle of the ink flow path and are forcibly discharged to the cap and bubbles that are generated in the cap, electricity is applied by the bubbles (electricity flows). Therefore, the detection sensor detects ink full and it is determined that the cap is full with ink, and an error is generated. When the apparatus is stopped according to this error occurrence, there is an effect of preventing air bubbles from leaking from the cap. However, since it is not a filter clogging or a suction pump failure, it is not necessary to receive maintenance work by a service person or the like. However, since an error has occurred, the apparatus is stopped and unnecessary maintenance work is performed.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a full tank detection method and an inkjet image forming apparatus that prevent erroneous detection.

In order to achieve the above object, the full tank detection method of the present invention discharges from an ink discharge port in an ink jet image forming apparatus that forms an image by discharging ink from the ink discharge port of a recording head onto a recording medium. In a full tank detection method for detecting whether or not a cap that receives ink is full with ink,
(1) Preliminarily determine whether the cap is full of ink,
(2) When it is determined that the tank is full, a defoaming operation is performed to remove the bubbles in the cap.
(3) After executing this defoaming operation, finally determine whether or not the cap is full of ink,
(4) It is characterized by detecting whether or not the tank is full based on this final judgment.

Here, the defoaming operation is
(5) An operation may be performed in which the cap is allowed to stand for a predetermined period of time and then the ink is sucked from the cap.

The defoaming operation is
(6) An operation may be performed in which the cap is hermetically sealed to decompress the inside thereof.

In order to achieve the above object, another full tank detection method of the present invention is the ink discharge port in an ink jet type image forming apparatus that forms an image by discharging ink from the ink discharge port of a recording head onto a recording medium. In a full tank detection method for detecting whether or not a cap that receives ink discharged from the tank is full of ink,
(7) Preliminarily determine whether the cap is full of ink;
(8) When it is determined that the tank is full, the cap is allowed to stand for a predetermined time, and then the ink is sucked from the cap.
(9) Finally, determine whether the cap is full of ink,
(10) It is characterized by detecting whether or not the tank is full based on this final judgment.

Here, prior to finally determining whether the cap is full of ink,
(11) The cap may be hermetically sealed to decompress the inside thereof, and then ink may be sucked from the cap.

In addition, an inkjet image forming apparatus of the present invention for achieving the above-described object is
(12) The full tank detection method described above is executed, and the ink sucked from the cap is reused.

  According to the present invention, it is preliminarily determined whether or not the inside of the cap is full of ink, and when it is determined that the cap is full, the defoaming operation is performed to erase the bubbles in the cap. By this defoaming operation, bubbles are removed from the cap and ink remains in the cap. Subsequently, it is finally determined whether or not the inside of the cap is full of ink, and based on this final determination, whether or not the ink is full is detected, so that erroneous detection can be prevented. That is, even if air bubbles are present at the time of the preliminary judgment, it is not detected that the ink is full unless the cap is full of ink. As a result, when there is no clogging of the filter or failure of the suction pump, no error occurs, and the decrease in productivity due to the stop of the apparatus can be minimized.

  The present invention has been realized in an inkjet image forming apparatus that forms an image by ejecting ink from a long recording head onto a recording medium.

  An example of an inkjet image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing an example of an inkjet image forming apparatus according to the present invention.

  An inkjet image forming apparatus (printer) 10 is connected to a host PC (personal computer) 12 that sends image information to the printer 10. In the printer 10, four (four) recording heads 22K, 22C, 22M, and 22Y are arranged side by side in the conveyance direction (arrow A direction) of the recording medium (roll paper in this case). The four recording heads 22K, 22C, 22M, and 22Y eject black, cyan, magenta, and yellow inks, respectively. These four recording heads 22K, 22C, 22M, and 22Y are so-called line heads, and extend in a direction orthogonal to the paper surface of FIG. 1 (a direction orthogonal to the arrow A direction). The lengths of these four recording heads 22K, 22C, 22M, and 22Y are slightly longer than the maximum width (the length in the direction perpendicular to the paper surface of FIG. 1) of the recording media that can be printed by the printer 10. Further, these four recording heads 22K, 22C, 22M, and 22Y are fixed and do not move during image formation (are in a non-moving state).

  A recovery unit 40 is incorporated in the printer 10 so that ink can be stably ejected from the four recording heads 22K, 22C, 22M, and 22Y. By using the recovery unit 40 to recover the four recording heads 22K, 22C, 22M, and 22Y, the ink ejection states from the four recording heads 22K, 22C, 22M, and 22Y are restored to the initial ink ejection state ( (Recovers normal ink ejection state). In the recovery unit 40, during the recovery operation, ink is supplied from the ink discharge port forming surfaces (face surfaces) 22Ks, 22Cs, 22Ms, 22Ys on which the respective ink discharge ports of the four recording heads 22K, 22C, 22M, 22Y are formed. A capping mechanism 50 is provided for removing water. The capping mechanism 50 is provided independently for each of the recording heads 22K, 22C, 22M, and 22Y. In the example of FIG. 1, six colors (that is, six capping mechanisms 50) are shown. The color component is a preliminary mechanism when the recording head is added. The capping mechanism 50 includes a suction cap 52, a cleaning blade (not shown), an ink removing member (not shown), a blade holding member (not shown), and the like.

  The roll paper P is supplied from the roll paper supply unit 24 and is conveyed in the direction of arrow A by the conveyance mechanism 26 incorporated in the printer 10. The transport mechanism 26 includes a transport belt 26a for loading and transporting the roll paper P, a transport motor 26b for rotating the transport belt 26a, and a roller 26c for applying tension to the transport belt 26a.

  When an image is formed on the roll paper P, after the recording start position of the roll paper P being conveyed reaches below the recording head 22K, the recording head 22K is controlled based on the recording data (image information). Ink is selectively ejected from a plurality of ink ejection openings. Similarly, a color image is formed by ejecting ink of each color onto the roll paper P in the order of the recording head 22C, the recording head 22M, and the recording head 22Y.

  The printer 10 includes main tanks 28K, 28C, 28M, and 28Y for storing ink supplied to the recording heads 22K, 22C, 22M, and 22Y, and the recording heads 22K, 22C, and 22M, in addition to the components and members described above. , 22Y are provided with various pumps (not shown) for supplying ink and performing a recovery operation.

  The electrical system of the printer 10 will be described with reference to FIG. FIG. 2 is a block diagram showing an electrical system of the printer of FIG.

  Recording data and commands transmitted from the host PC 12 are received by the CPU 100 via the interface controller 102. The CPU 100 is an arithmetic processing unit that performs overall control such as reception of recording data of the printer 10, recording operation, handling of the roll paper P, and the like. After analyzing the received command, the CPU 100 renders the image data of each color component of the recording data by developing a bitmap on the image memory 106. As an operation process before recording, the capping motor 122 and the head up / down motor 118 are driven via the output port 114 and the motor drive unit 116, and the recording heads 22K, 22C, 22M, and 22Y are connected to the capping mechanism 50 (see FIG. 1). ) To move to the recording position (image forming position).

  Subsequently, the roll motor (not shown) that feeds the roll paper P through the output port 114, the motor drive unit 116, the transport motor 120 that transports the roll paper P at a low speed, and the like are driven to drive the roll paper P. -The paper P is conveyed to the recording position. The leading end position of the roll paper P is detected by a leading edge detection sensor (not shown) for determining the timing (recording timing) at which ink starts to be discharged onto the roll paper P conveyed at a constant speed. Thereafter, in synchronization with the conveyance of the roll paper P, the CPU 100 sequentially reads out the corresponding color recording data from the image memory 106, and controls the recording heads 22K, 22C, 22M, and 22Y to read the read data. Transfer via the circuit 112.

  The operation of the CPU 100 is executed based on a processing program stored in the program ROM 104. The program ROM 104 stores processing programs and tables corresponding to the control flow. A work RAM 108 is used as a working memory. During the cleaning and recovery operations of the recording heads 22K, 22C, 22M, and 22Y, the CPU 100 drives the pump motor 124 via the output port 114 and the motor driving unit 116 to control ink suction and the like.

  A head holder for holding the recording heads 22K, 22C, 22M, and 22Y will be described with reference to FIG. FIG. 3 is a perspective view showing the head holder and the like.

  The recording heads 22K, 22C, 22M, and 22Y described above are detachably attached to a rectangular parallelepiped head holder 30. The head holder 30 is moved up and down in the direction of arrow B by a head up / down motor 118 (see FIG. 2). The head holder 30 is configured to be able to stop at predetermined four positions when moving up and down, and as these four positions, a kipping position, a wiping position, a retracted position, and a printing position (recording position) are set. . The kipping position is a position where the ink discharge port forming surfaces 22Ks, 22Cs, 22Ms, and 22Ys (see FIG. 1) of the recording heads 22K, 22C, 22M, and 22Y are blocked by the cap of the capping mechanism 50. The wiping position is a position when the ink discharge port forming surfaces 22Ks, 22Cs, 22Ms, and 22Ys are wiped by the blade 66 (see FIG. 4) (the position shown in FIG. 7). The retracted position is a position where the ink discharge port forming surfaces 22Ks, 22Cs, 22Ms, and 22Ys are wetted with ink (the position shown in FIG. 6). The printing position is a position at which ink is ejected from the recording heads 22K, 22C, 22M, and 22Y onto the recording medium (the position shown in FIG. 8).

  A cap plate 32 that closes the cap 62 (see FIG. 4 and the like) is attached to the head holder 30. The cap plate 32 seals the lip portion (upper end portion) of the cap 62 (see FIG. 6) when the recording heads 22K, 22C, 22M, and 22Y are in the printing position. The inside is kept airtight. The capping mechanism 50 is attached to the slide plate 52 and is configured to be movable in the direction of arrow C by a capping motor 122 (see FIG. 2). The slide plate 52 is configured to stop at the capping position (recovery position) and the printing position when moving in the direction of arrow C. Further, the wiping operation is performed by moving the slide plate 52 in the right direction of the arrow C direction in FIG.

  The capping mechanism 50 described above will be described with reference to FIGS.

  FIG. 4 is a perspective view schematically showing the capping mechanism. FIG. 5 is an enlarged view showing one end portion of the retainer in the longitudinal direction (one end portion in the longitudinal direction in FIG. 4) and its periphery. FIG. 6 is a partial cross-sectional view showing the capping mechanism located at the retracted position. FIG. 7 is a partial cross-sectional view showing the capping mechanism located at the wiping position. FIG. 8 is a partial cross-sectional view showing the capping mechanism located at the printing position. In these drawings, the same components as those shown in FIG. 3 are denoted by the same reference numerals. In these drawings, the capping mechanism 50 for the recording head 22K is shown, but the capping mechanisms 50 for the other recording heads 22C, 22M, and 22Y have the same structure. In the following description, the case of the recording head 22K will be described as an example, but the same applies to the other recording heads 22C, 22M, and 22Y.

  In the capping mechanism 50, various members and parts are fixed to an elongated rectangular parallelepiped recovery rod 60 extending in the length direction of the recording head 22K (direction perpendicular to the paper surface of FIG. 6 and the like). A cap 62 for closing (capping) the ink discharge port forming surface 22Ks of the recording head 22K is attached to the central portion of the recovery rod 60 in the width direction (arrow C direction). The cap 62 surrounds and closes the face surface 22Ks, and has an elongated elliptical shape as shown in FIG.

  An ink reservoir (not shown) in which the ink pushed out from the nozzle 22Kb (not shown) of the recording head 22K is collected is formed in a portion below the cap 62 inside the recovery rod 60. A recycling hole (opening) for discharging ink recycled to the sub tank 206 (see FIG. 9) by the suction pump 204 (see FIG. 3) is provided at one end of the ink reservoir (one longitudinal end of the recovery bowl 60). 64 is formed.

  As shown in FIG. 5, the other end in the longitudinal direction of the cap 62 has a hole into which the electrode shaft 80 for detecting whether or not the ink is full in the cap 62 is inserted. An electrode shaft 80, which is a SUS shaft, is inserted into the hole. A SUS plate electrode A 82 is attached to the electrode shaft 80, and is fixed to the recovery rod 60 via the electrode base 84. In addition, an electrode B86 is inserted into the slit near the hole in which the electrode shaft 80 of the cap 62 is inserted. The electrode B86 is fixed to the recovery rod 60 via the electrode base 84 in the same manner as the electrode A82. When the cap 62 is full with ink, it is detected that the electrodes A82 and B86 are energized and are full. However, when part of the cap 62 is filled with ink and the remaining part is filled with bubbles, it is detected that the electrodes A82 and B86 are energized and full. The printer 10 is configured to erase the bubbles (bubbles) in the cap 62 (execute the defoaming operation) and detect when the cap 62 is full with ink. This point will be described later.

  A blade 66 for wiping (wiping) the face surface 22Ks of the recording head 22K is disposed at one end of the recovery rod 60 in the width direction. The blade 66 is made of an elastic body (is an elastic blade) and is held by a blade holder 68 fixed to the recovery rod 60. The blade 66 is attached with an ink carrying blade 69 for carrying ink. Further, an ink absorber 67 that absorbs ink is disposed at the lower end of the ink transport blade 69. The ink transport blade 69 has a function of guiding the ink wiped off by the blade 66 to the lower ink absorber 67.

  As shown in FIG. 6 and the like, the capping mechanism 50 includes an elongated rectangular parallelepiped cap frame 70 that is disposed at the center in the width direction of the recovery rod 60 and extends in the longitudinal direction. The cap frame 70 has a plurality of ink removing members 72 for removing ink from the face surface 22Ks of the recording head 22K by capillary action, and a distance between the plurality of ink removing members 72 and the face surface 22Ks at a predetermined distance (predetermined interval). An interval regulating member 74 that regulates to be held is held. The ink removing member 72 and the interval regulating member 74 are urged upward (in the direction toward the face surface 22Ks) by a spring 78. In addition, a blade ink recycling hole 76 connected to the ink absorber 67 is formed in the cap frame 70. The ink wiped off from the face surface 22Ks by wiping is once introduced into the cap 62 through the blade ink recycling hole 76.

  During the recovery operation, the capping mechanism 50 is positioned directly below the recording head 22K, the recording head 22K is lowered, and the face surface 22Ks contacts the upper end of the interval regulating member 74 (moves to the recovery position). Recovery processing such as recovery operation is started. In the recovery process, ink is ejected from the ink ejection port of the face surface 22Ks.

  With reference to FIG. 9, the recovery unit incorporated in the image forming apparatus 10 will be described.

  FIG. 9 is a schematic diagram illustrating a recovery unit of the image forming apparatus. Although FIG. 9 shows a recovery unit that supplies ink to the recording head 22K and recovers the recording head 22K, the other recording heads 22C, 22M, and 22Y are recovered in the same procedure by the recovery unit having the same structure. In FIG. 9, the arrow indicating the ink movement indicates the ink flow when the recovery operation of the recording head is executed.

  During printing, the recording heads 22K, 22C, 22M, and 22Y are fixed at predetermined positions above the roll paper P, and the six capping mechanisms 50 are arranged so that the recording heads 22K, 22K, It is located on the side of 22C, 22M, 22Y. On the other hand, when the recovery operations of the recording heads 22K, 22C, 22M, and 22Y are performed, the recording heads 22K, 22C, 22M, and 22Y move upward, and four of the six capping mechanisms 50 have four capping mechanisms 50. The recording heads 22K, 22C, 22M, and 22Y are positioned directly below the ink discharge port forming surfaces 22Ks, 22Cs, 22Ms, and 22Ys.

  When the ink discharge state from the recording head 22K is restored to the initial discharge state, first, the pump motor 124 (see FIG. 2) is activated under the control of the CPU 100 (see FIG. 2), and the pressurization pump 202 starts operating. To do. Prior to the start of this operation (in advance), the recovery valve 204b is closed and the recycle valve 204c is open. Note that the CPU 100 controls the suction pump 204 to be activated almost simultaneously with the pressurizing pump 202.

  When the pressurizing pump 202 is driven, the ink in the sub tank 206 is directed to the common liquid chamber 22Ka of the recording head 22K via the pressurizing pump 202, but the recovery valve 204b on the outlet side is closed. All of the ink thus discharged is pushed out from the nozzle 22Kb of the recording head 22K to the cap of the capping mechanism 50. As a result, the nozzles 22Kb of the recording head 22K are restored to a healthy state (initial ink ejection state).

  Ink pushed out to an ink reservoir (not shown) in the cap of the capping mechanism 50 is sucked through the filter 208, the recycle valve 204c, and the suction pump 204 in this order when the suction pump 204 is driven, and is sucked into the sub tank 206. It will be recycled because it returns. Further, the sub tank 206 is provided with an atmosphere release valve 204d for communicating the inside with the atmosphere. Further, a supply valve 212 and a filter 214 are attached to the ink supply pipe 210 between the suction pump 204 and the ink cartridge 28K.

  In addition to the above-described recovery operation, various inks for the purpose of removing bubbles grown in the common liquid chamber 22Ka by circulating ink between the sub tank 206 and the recording head 22K with the recovery valve 204b open. The details are omitted.

  With reference to FIG. 10, the procedure of the recovery operation for recovering the recording head will be described.

  FIG. 10 is a flowchart showing a general recovery operation procedure of the recording head.

  The flow shown in FIG. 10 is executed by the CPU 100 (see FIG. 2) according to the control program stored in the program ROM 104 (see FIG. 2). Since the recovery operations of the recording heads 22K, 22C, 22M, and 22Y are simultaneously performed in the same procedure, the recording head 22K will be described as an example here. In starting this recovery operation, first, the recording head 22K is moved from the capping position to the recovery position (S1001). At the recovery position, the face surface 22Ks of the recording head 22K is set so as to contact the interval regulating member 74 (see FIG. 6 and the like). That is, when the recording head 22K is positioned at the recovery position, the interval regulating member 74 is in contact with the face surface 22Ks.

  Subsequently, the recovery valve 204b (see FIG. 9) is closed (S1002), and the suction pump 204 and the pressure pump 202 are driven (turned ON) (S1003, S1004). By driving these two pumps 204 and 202, ink is pushed out from the nozzle 22Kb of the recording head 22K and guided to an ink reservoir (not shown) below the cap 62 (see FIG. 4 and the like). At this time, since the above-described capping mechanism 50 is used, ink is efficiently removed from the face surface 22Ks by capillary action regardless of the type of ink pushed out from the nozzle (wetting with the face surface 22Ks). . Since the ink accumulated in the ink reservoir (not shown) is returned to the sub tank 206 by the suction pump 204 during operation, the ink is recycled.

  The above recovery operation (operation in which the recording head 22K is positioned at the recovery position, the recovery valve 204b is closed, and the suction pump 204 and the pressure pump 202 are turned on) is continued for a predetermined time (S1005). After the predetermined time has elapsed, the pressure pump 202 is stopped (turned off) (S1006). Subsequently, the recording head 22K is returned to the capping position (S1007), and preliminary ejection is performed a predetermined number of times (S1008). Subsequently, the ink adhering to the face surface 22Ks is wiped off by wiping (wiping) the face surface 22Ks of the recording head 22K with the blade 66 (see FIG. 6 and the like) (S1009). When the predetermined time has passed (S1010), the suction pump 204 is stopped (turned off) (S1011), and the ink is sucked from the ink reservoir (not shown) in the capping mechanism 50 (see FIG. 1 and the like). To stop and end this flow.

  With reference to FIG. 11, a full tank detection method for detecting whether or not the inside of the cap 62 shown in FIG. 4 and the like is full with ink (a predetermined amount of ink has been accumulated) will be described. FIG. 11 is a flowchart showing a procedure for detecting whether or not the inside of the cap 62 shown in FIG. 4 or the like is full with ink (a predetermined amount of ink is stored).

  The flow shown in FIG. 11 is valid (activated and in a full tank detection state) from the suction pump ON (S1003) to the pressure pump OFF (S1006) in the flow chart of the recovery operation shown in FIG. Become. While the flow shown in FIG. 11 is activated, it is always detected by the electrode A82 and the electrode B86 (detection sensor) whether or not the inside of the cap 62 is filled with ink or bubbles (or ink and bubbles). When the full tank detection operation shown in FIG. 11 is activated, it is first determined whether or not the electrodes A82 and B86 shown in FIG. 5 are energized and become full (S1101). The electrode A82 and the electrode B86 are energized when the cap 62 is filled with ink or bubbles (or ink and bubbles).

  When the electrode A 82 and the electrode B 86 are energized in this way, it is conventionally determined that the cap 62 is full of ink and the filter 208 shown in FIG. The printer 10 (see FIG. 1 and the like) has generated an error. However, in the flow of FIG. 11, even if the electrode A82 and the electrode B86 are energized, it is determined whether the cap 62 is filled with ink or bubbles (or ink and bubbles) and the full state is detected. It has become. The printer 10 (see FIG. 1 and the like) generates an error only when the inside of the cap 62 is full with ink.

  When the full tank detection operation shown in FIG. 11 is started and the electrodes A82 and B86 are energized and full tank is detected (S1101, it is preliminarily determined that the inside of the cap 62 is full of ink. In the case), in order to determine whether or not bubbles are generated in the cap 62, first, a defoaming operation for removing the bubbles in the cap 62 is executed. In this defoaming operation, the cap 62 is allowed to stand for a predetermined time (for example, 20 seconds) to stand by (S1102), and then the suction pump 204 is operated for a predetermined time (for example, 5 seconds) to suck ink from the cap 62. Operation (S1103).

  After this suction operation is completed, it is determined again whether or not the inside of the cap 62 is full of ink (S1104, which is an example of a final determination according to the present invention, but here S1104 is a final determination). Rather, it is an intermediate decision.) As a result of this determination, if it is not determined that the tank is full, there is no clogging of the filter 208 and there is no failure of the suction pump 204, so the process proceeds to S1003 in FIG. 10 and the recovery operation is continued (S1105). End the flow. On the other hand, if it is determined in S1104 that the tank is full, there is a possibility that the filter 208 is clogged or the suction pump 204 is broken, so an operation for confirming these is executed. In this operation, first, the recording head 22K and the like are moved to the printing position, and the cap 62 (see FIG. 4 and the like) is sealed with the cap plate 32 (see FIG. 6 and the like) (the cap 62 is airtight) (S1106). . Subsequently, the suction pump 204 (see FIG. 9) is operated for a predetermined time (for example, 10 seconds) (S1107), the inside of the cap is decompressed, and the bubbles in the cap 62 are erased (defoamed). Subsequently, the recording head 22K and the like are moved to the recovery position (S1108), and the suction pump 204 (see FIG. 9) is operated for a predetermined time (for example, 5 seconds) (S1109) to suck the ink in the cap 62.

  Subsequently, it is determined again whether or not the inside of the cap 62 is full with ink (S1110, which is also an example of a final determination in the present invention). As a result of this determination, if it is not determined that the tank is full, there is no clogging of the filter 208 or failure of the suction pump 204, so the process proceeds to S1003 in FIG. 10 to continue the recovery operation (S1112), and the flow in FIG. Exit. On the other hand, if it is determined in S1110 that the tank is full, the defoaming operation has been exhausted as described above, and therefore there is a high possibility of clogging of the filter 208 or failure of the suction pump 204, causing an error in the printer 10. (S1111) to perform necessary processing such as stopping the apparatus.

  As described above, the setting of the standby time as the defoaming operation (S1102) and the cap 62 is hermetically sealed to depressurize the inside (S1107). As described above, an increase in waste liquid from the recording head 22K, a decrease in the suction amount due to clogging of the filter 208 (see FIG. 9), or a failure of the suction pump 204 (see FIG. 9) can be considered. In such a case, when the recovery operation is continued further, there is a high risk of ink leaking from the cap 62, so an error is generated in the printer 10. When full tank is no longer detected in the process of operation, it can be determined that there is no problem even if the bubble generated by the defoaming operation disappears and the normal operation is restored.

  As described above, according to the printer 10, it is possible to reliably prevent ink leakage and bubble leakage from the cap 62, and to minimize a decrease in productivity due to the stop of the apparatus.

It is a schematic diagram which shows an example of the inkjet type image forming apparatus of this invention. FIG. 2 is a block diagram illustrating an electrical system of the printer of FIG. 1. It is a perspective view which shows a head holder etc. It is a perspective view which shows the outline of a capping mechanism. It is an enlarged view which shows the longitudinal direction one end part (longitudinal direction one end part in FIG. 4) and its periphery of a retainer. It is a partial cross section figure which shows the capping mechanism located in a retracted position. It is a partial cross section figure which shows the capping mechanism located in a wiping position. It is a partial cross section figure which shows the capping mechanism located in a printing position. It is a schematic diagram showing a recovery unit of the image forming apparatus. FIG. 6 is a flowchart showing a general recovery operation procedure of a recording head. FIG. 5 is a flowchart showing a procedure for detecting whether or not the inside of the cap shown in FIG. 4 and the like is full with ink (a predetermined amount of ink is stored).

Explanation of symbols

10 Printer 22K, 22C, 22M, 22Y Recording head 62 Cap 82 Electrode A
86 Electrode B

Claims (6)

Detects whether the cap that receives ink discharged from the ink discharge port is full with ink in an inkjet image forming apparatus that forms an image by discharging ink to the recording medium from the ink discharge port of the recording head In the full tank detection method,
Preliminarily determine whether the cap is full of ink,
When it is determined that the tank is full, a defoaming operation is performed to erase the bubbles in the cap,
After performing this defoaming operation, finally determine whether the cap is full of ink,
A full tank detection method comprising detecting whether or not the tank is full based on the final judgment. The defoaming operation is
2. The full tank detection method according to claim 1, wherein the operation is an operation of allowing the cap to stand for a predetermined time and waiting, and then sucking ink from the cap. The defoaming operation is
2. The full tank detection method according to claim 1, wherein the cap is hermetically sealed and the inside thereof is decompressed. In an inkjet image forming apparatus that forms an image by ejecting ink from the ink ejection port of the recording head to the recording medium, it detects whether or not the cap that receives the ink discharged from the ink ejection port is full of ink. In the full tank detection method,
Preliminarily determine whether the cap is full of ink,
When it is determined that the tank is full, the cap is allowed to stand for a predetermined time, and then the ink is sucked from the cap.
Finally determine whether the cap is full of ink,
A full tank detection method comprising detecting whether or not the tank is full based on the final judgment. Prior to finally determining whether the cap is full of ink,
5. The full tank detection method according to claim 4, wherein the cap is hermetically sealed and the inside thereof is decompressed, and then ink is sucked from the cap. An ink jet type image forming apparatus, wherein the full tank detection method according to any one of claims 1 to 5 is executed, and the ink sucked from the cap is reused.

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