JP2009248547A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer configured to check nozzles so that printing throughput and printing quality can be obtained in accordance with user's convenience or a user's demand. <P>SOLUTION: A control unit 30 of the inkjet printer 1 is configured to check the nozzles by means of a nozzle checking mechanism with different performance frequency based on setting reliability set by a reliability setting unit 37 composed of a non-volatile memory. In the case of printing a fine image, the high reliability is established, and the nozzles are checked for every issue of one label, then, high printing quality free from image-missing is maintained. Contrarily, in the case the user wants to quickly print an image of printing quality enough to prevent misreading letters, the low reliability is established as the setting reliability, and when a series of print job is finished, the nozzles are checked, accordingly, the reduction in printing throughput caused by frequent nozzle-checking is prevented. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink jet printer provided with nozzle check means for detecting whether or not there are nozzles that cannot eject ink or other liquid droplets in the ink jet head or nozzles that are insufficient to eject ink or other liquid droplets. More specifically, the present invention relates to an ink jet printer that can perform nozzle check of an ink jet head with reliability according to a user's request.

  In an inkjet printer, each nozzle of the inkjet head becomes clogged due to thickening of droplets such as ink remaining in the nozzles, mixing of bubbles, adhesion of foreign matters, etc., making it impossible to eject ink droplets It may fall. In addition, the nozzle may be partially clogged, resulting in a discharge failure state in which a sufficient amount of ink droplets cannot be discharged. When printing is performed using an ink jet head including a nozzle that has fallen into such a state (hereinafter referred to as a defective nozzle), the print quality deteriorates. Therefore, the ink jet head is regularly or at a predetermined timing. Needs to be moved out of the print area to perform the head cleaning process.

Patent Document 1 discloses a printer that performs nozzle check and head cleaning. In this printer, when power is turned on, nozzle check and head cleaning are performed as part of the startup process. Also, a nozzle check is performed to check the number of defective nozzles. If the number of defective nozzles is greater than or equal to a threshold set by the user, head cleaning corresponding to the number of defective nozzles is performed. If the number of defective nozzles is less than the threshold, head cleaning is performed. Do not do.
JP 2007-7960 A

  Here, it takes about 3 to 4 seconds for the nozzle check to determine whether or not each nozzle of the inkjet head is a defective nozzle. If the nozzle check is frequently performed, the printing throughput is greatly reduced. If the frequency of nozzle check is lowered, the possibility of printing using defective nozzles increases, and the print quality as a whole deteriorates.

  In view of this point, an object of the present invention is to propose an ink jet printer capable of performing a nozzle check so that printability and print quality according to user convenience or request can be obtained.

  In order to solve the above problems, the ink jet printer of the present invention can set the nozzle check means for detecting whether or not the nozzle of the ink jet head is a defective nozzle, and the reliability of the nozzle check by the nozzle check means. Control for executing the nozzle check by the nozzle check means in an execution form associated in advance with the set reliability based on the set reliability set in the reliability setting means and the reliability setting means And means. The reliability of the nozzle check is the degree to which the nozzle check is performed. When the reliability is set to a high level, the check is performed more strictly. Examples of nozzle check execution modes include the execution frequency, execution timing, full nozzle check, and partial nozzle check.

  Here, at least two types of reliability, ie, high reliability and low reliability, can be set in the reliability setting means, and the control means records when the set reliability is the high reliability. When the nozzle check is performed at a time point after a predetermined line of printing such as printing of one line or one page of paper or one label is completed, and the set reliability is the low reliability, The time point after the end of a series of predetermined print jobs can be the nozzle check execution time. Further, the set reliability of the reliability setting means may be rewritable. For example, the reliability may be set or rewritten by receiving a command from the host device.

  In the ink jet printer of the present invention, the execution mode such as the frequency of nozzle check is determined based on the set reliability set in the reliability setting means. For example, in the case of printing a fine image, it is possible to maintain a high print quality that does not cause image loss or the like by frequently setting the reliability of the setting and performing a nozzle check. it can. Conversely, when it is desired to print characters and the like quickly with a print quality that does not cause misreading, the setting reliability may be set to a low reliability so that the nozzle check is not performed more than necessary.

  Next, the ink jet printer of the present invention has nozzle check execution time setting means capable of setting the execution time of the nozzle check by the nozzle check means, and the control means is set by the nozzle check execution time setting means. The nozzle check is executed at the execution time.

For example, the nozzle check execution time set by the nozzle check execution time setting means may be at least one of the following (1) to (4).
(1) When the power of the ink jet printer is turned on (2) When the open / close cover is closed When the open / close cover is closed (3) When the shock detection means for detecting the shock applied to the ink jet printer is provided When printing is started after the impact is detected by the impact detection means (4) When a predetermined time has elapsed from the previous nozzle check execution time

  At such a point in time, there is a high possibility that defective nozzles are generated because each nozzle is left for a long period of time. Further, defective nozzles may be generated due to the ink meniscus being destroyed by impact. Therefore, it is desirable to always perform a nozzle check at these times. Further, since the occurrence frequency of such an event is low, even if the nozzle check is executed, the print throughput is not significantly reduced.

  Next, the ink jet printer of the present invention has a head cleaning unit for recovering the defective nozzle, and the control unit sets the result of the nozzle check and the reliability setting unit after executing the nozzle check. Whether or not to perform head cleaning by the head cleaning means is determined based on the set reliability set.

  For example, when at least two types of reliability, that is, high reliability and low reliability, can be set in the reliability setting means, the control means detects only one defective nozzle by the nozzle check. In some cases, the head cleaning may be executed only when the set reliability is the high reliability.

  It is possible to perform head cleaning at a frequency according to the set reliability. When the reliability is high, the nozzle check is frequently performed and the head cleaning is frequently performed, so that good print quality is maintained. it can. In the case of low reliability, the frequency of nozzle check and head cleaning is reduced, and the print quality can be reduced, but the print throughput can be increased.

  Next, the ink jet printer of the present invention has NG information print setting means capable of setting whether or not to print NG information indicating defective printing such as a defective print line, a defective print page, or a defective print label, When the nozzle check is performed and the defective nozzle is detected after the printing of a predetermined segment such as printing for one line or one page of recording paper or printing of one label is completed, the control means When printing of the NG information is set by the NG information print setting means, the NG information is printed on the recording paper. Note that printing performed by a defective nozzle is called defective printing.

  For example, when the set reliability is high reliability, a nozzle check is performed each time printing of a predetermined separation such as printing for one line or one page of recording paper or printing of one label is completed, and a defective nozzle is detected. Then, head cleaning is performed. If the defective nozzle is not recovered by the head cleaning, the print quality of the next printing is deteriorated. In the case where such rare print defects are not allowed, if NG information printing is set in the NG information print setting unit, the NG information is changed when a defective nozzle is detected by the nozzle check after printing. Overprinting is performed, and a printed matter using defective nozzles is displayed. Therefore, it is possible to reliably eliminate defective print lines, defective print pages, or defective print labels performed using the defective nozzle.

  Next, the ink jet printer of the present invention has a communication means for transmitting to the upper device that the defective printing has been performed and receiving an instruction on the necessity of reprinting from the upper device, and the control When the nozzle check is performed and the defective nozzle is detected after the printing of a predetermined separator such as one line or one page of recording paper or one label is completed, the defective printing is performed. Is sent, and when the communication means receives the command for requesting reprinting, printing for one line or one page of the recording paper or printing of a predetermined section such as one label is performed. It is characterized by making it.

  Even in this case, as in the case of printing of the above NG information, it is possible to reliably eliminate printing due to the use of defective nozzles. Further, since the user can confirm whether or not the printed material is usable, it is possible to check the recording paper, the label, the ink, and the like as compared with the case where the NG information is printed and displayed as the printed material in which the defective nozzle is used. Waste can be reduced.

  Here, instead of making the user check each time printing is performed, a reprint necessity setting unit capable of setting necessity of reprinting when defective printing is performed is arranged. When the nozzle check is performed and the defective nozzle is detected after the printing of a predetermined section such as printing for one line or one page or one label is completed, the reprinting necessity setting unit detects If the setting for requesting reprinting is made, printing for one line or one page of the recording paper or printing at a predetermined interval such as one label may be performed. Further, reprinting may be performed after performing predetermined head cleaning.

  In the ink jet printer of the present invention, the execution mode of the nozzle check such as the execution frequency and the execution time is determined based on the setting reliability set in the reliability setting means. For example, by setting a high reliability when the user requests high print quality, and setting a low reliability when requesting the printing speed, by setting according to the user's desire, An ink jet printer that can perform printing with a printing quality and a printing throughput according to a user's request can be realized.

  Embodiments of an ink jet printer according to the present invention will be described below with reference to the drawings.

(overall structure)
FIG. 1 is an external perspective view of an ink jet printer. FIG. 2 is an external perspective view showing a state in which the roll paper cover and the ink cartridge cover are fully opened. FIG. 3 is a perspective view showing the printer mechanism with the outer case removed to show the internal structure of the ink jet printer.

  The ink jet printer 1 includes a box-shaped outer case 2, and a roll paper cover 2 a (open / close cover) and an ink cartridge cover 2 b (open / close cover) are arranged on the front side of the outer case 2. A paper discharge port 3 for discharging the recording paper after printing is formed on the top. As shown in FIG. 2, when the roll paper cover 2a is opened, the roll paper storage section 4 formed in the exterior case 2 is opened, and the roll paper 5 stored therein is replenished or replaced. be able to. When the ink cartridge cover 2b is opened, the cartridge mounting portion 7 for mounting the ink cartridge 6 enclosing the ink liquid is opened, and the ink cartridge 6 can be mounted and removed.

  As shown in FIG. 2, an opening / closing sensor for detecting that the roll paper cover 2 a is closed at the edge of the opening communicating with the roll paper storage unit 4 or the cartridge mounting unit 7 is provided on the front portion of the outer case 2. 2c and an open / close sensor 2d for detecting that the ink cartridge cover 2b is closed are attached. An impact sensor 2e for detecting an impact applied to the inkjet printer 1 from the outside is attached to a predetermined position inside the outer case 2. As the impact sensor 2e, for example, a sensor that detects the movement of a weight due to acceleration at the time of impact using a piezoelectric material or a position sensor is used.

  As shown in FIG. 3, the printer mechanism unit 10 covered with the outer case 2 includes a printing mechanism 11 disposed on the upper side of the roll paper storage unit 4 and each unit disposed on the left side of the roll paper storage unit 4. A control unit 30 that performs control, a cartridge mounting unit 7 disposed on the right side of the roll paper storage unit 4, and a head cleaning mechanism 40 disposed on the cartridge mounting unit 7 are provided. Further, as will be described later, in the vicinity of the paper discharge mechanism 3, the paper feed mechanism that transports the recording paper 5 a drawn from the roll paper 5 stored in the roll paper storage unit 4 via the printing position by the printing mechanism 11. Various mechanisms such as a recording paper cutting mechanism are provided.

  FIG. 4 is a schematic cross-sectional view showing the internal structure of the inkjet printer 1. The internal structure of the inkjet printer 1 will be described with reference to FIGS. 3 and 4. The printing mechanism 11 disposed above the roll paper storage unit 4 and the cartridge mounting unit 7 includes an inkjet head 12, a carriage 13 on which the inkjet head 12 is mounted, and a horizontal carriage shaft 14 for guiding the carriage 13. And. The carriage 13 is connected to an output shaft of a carriage motor 16 by an endless belt 15, and the eject head 12 reciprocates in the printer width direction, that is, the paper width direction of the roll paper 5 based on the rotation of the carriage motor 16.

  The inkjet head 12 includes a nozzle surface 12 a on which a plurality of nozzles for ejecting ink are formed. The nozzle surface 12 a is exposed downward on the lower side of the carriage 13. A back pressure adjustment unit 17 connected to the inkjet head 12 is mounted on the upper surface of the carriage 13. The back pressure adjustment unit 17 is connected to the tip of the ink supply tube 19 via a damper unit 18 connected to the back side thereof. It is connected to the. When the inkjet head 12 reciprocates through a printing position defined by the upper surface of the platen 20 disposed horizontally on the upper side of the roll paper storage unit 4, nozzles are formed on the recording paper 5 a sent to the upper surface of the platen 20. Printing is performed by ejecting ink droplets from each nozzle on the surface 12a. When printing is not performed, the inkjet head 12 moves to the right end of the carriage shaft 14 and returns to a standby position facing the head cleaning mechanism 40.

  Next, the paper feeding mechanism will be described mainly with reference to FIG. 4. On the rear side of the platen 20 (upstream in the conveying direction), the rear paper feeding roller 21 and the rear paper pressing roller 22 are arranged in the printer width direction. It is stretched horizontally. A rear paper pressing roller 22 is pressed against the rear paper feeding roller 21 from above with a predetermined pressing force via the recording paper 5a. A front paper feed roller 23 and a front paper presser roller 24 are arranged on the front end side of the platen 20. A front paper pressing roller 24 is pressed against the front paper feeding roller 23 from above via a recording paper 5a. The rear paper feed roller 21 and the front paper feed roller 23 are rotationally driven in synchronization by a paper feed motor (not shown).

  The roll paper 5 is set by closing the roll paper cover 2a in a state where the length of the roll paper 5 is pulled out from the paper discharge port 3 by hand. The recording paper 5 a fed out from the roll paper 5 in the roll paper storage unit 4 is conveyed along a conveyance path passing through the printing position on the upper surface of the platen 20 in a state where a predetermined tension is applied by the tension guide 25. When the paper feed motor is driven and controlled, the rear paper feed roller 21 and the front paper feed roller 23 rotate, and the recording paper 5a is intermittently fed for every one line printing with a constant feed amount. The inkjet head 12 is driven in synchronization with the feeding of the recording paper 5a, and printing is performed on the surface of the recording paper 5a passing through the printing position. The printed recording paper 5a is stopped in a state where it is discharged from the paper discharge port 3, and the printing portion at the leading end of the recording paper 5a is cut by the recording paper cutting mechanism 8 disposed in the vicinity of the paper discharge port 3, and printed. A piece of recording paper is issued.

(Recording paper and paper detection sensor)
FIG. 5 is an explanatory diagram showing the configuration of the recording paper 5a and the arrangement position of the sensor for detecting the recording paper arranged on the conveyance path. In this example, reflection type photosensors 26 and 29 and a transmission type photosensor 27 are provided as detection sensors.

  The recording paper 5a is a label paper, and is composed of a long peeling base 5b and a rectangular label 5c attached to the surface in a state where it can be peeled at a predetermined interval. In order to indicate the position of each label 5c, black marks 5d are printed in advance at regular intervals on the back surface of the release mount 5b. The black mark 5d is printed on a portion of the back surface of the peeling mount 5b corresponding to the downstream edge in the transport direction of each label 5c.

  Next, the reflective photosensor 26 is disposed near the rear end of the platen 20 in the transport path. The reflection type photo sensor 26 detects the reflectance of the label sheet passing through the detection position, and thereby detects the position of the black mark 5d, that is, the position of the label 5c. The transmissive photosensor 27 is disposed upstream of the reflective photosensor 26 in the conveyance path. The transmissive photosensor 27 is disposed between the rear paper feed roller 21 and the tension guide 25, and detects the transmittance of the label paper conveyed through this position, whereby the black mark 5d is printed. Even if not, the position of the label 5c is detected. The reflection type photo sensor 29 is mounted at one end of the carriage 13 in the printer width direction, and detects the width of the label paper 5 while moving in the paper width direction.

(Head cleaning mechanism and nozzle check mechanism)
FIG. 6 is a perspective view showing the head cleaning mechanism 40 taken out. The head cleaning mechanism 40 includes a head cap 41 for sealing the nozzle surface 12 a of the inkjet head 12, a wiper 42 for wiping off ink and foreign matters attached to the nozzle surface 12 a, and the inkjet head head 12. An ink suction part 43 for sucking ink remaining in the nozzle or clogging is provided. The head cap 41, the wiper 42, and the ink suction unit 43 are attached to the frame 44 of the head cleaning mechanism 40. The frame 44 is fixed to the main body frame of the inkjet printer 1 that supports the carriage shaft 14, the platen 20, and the like.

  The head cap 41 is disposed directly below the nozzle surface 12a at the standby position, and has an upward sealing surface 41a that faces the nozzle surface 12a. The head cap 41 is configured to be vertically slidable in a direction perpendicular to the nozzle surface 12 a, that is, a direction orthogonal to the carriage shaft 14 by operating a drive mechanism (not shown). Thereby, the head cap 41 moves in a direction in which the sealing surface 41a approaches or moves away from the nozzle surface 12a. A drive mechanism that is a drive source of the head cap 41 operates based on a control signal from the control unit 30 to raise or lower the head cap 41.

  FIG. 7 is a partial cross-sectional view showing a state where the inkjet head 12 and the head cap 41 are facing each other. As shown in this figure, the head cap 41 has a box shape in which the edge 41b of the sealing surface 41a stands vertically, and is made of an elastic material such as rubber. The head cap 41 has a size and a shape that allows the head cap 41 to be in close contact with the nozzle surface 12a while covering the nozzle forming portion of the nozzle surface 12a with the edge 41b. A suction tube extending from a pump motor (not shown) provided in the ink suction portion 43 is connected to the recess 41c surrounded by the sealing surface 41a and the edge portion 41b. When the pump motor is operated with the edge 41b in close contact with the nozzle surface 12a, the sealed space surrounded by the recess 41c and the nozzle surface 12a is decompressed by the suction force of the pump motor, and remains in each nozzle of the inkjet head 12. The sucked ink is sucked and discharged into the recess 41c.

  The wiper 42 is a plate-like member made of an elastic material such as rubber, and is slidable up and down by a guide member (not shown) fixed to the frame 44 of the head cleaning mechanism 40. The wiper 42 is configured to be movable in a direction perpendicular to the nozzle surface 12a, like the head cap 41, by operating a drive mechanism (not shown). When wiping the nozzle surface 12a with the wiper 42, the wiper 42 is lifted with the nozzle surface 12a shifted laterally from directly above the wiper 42, and the tip of the wiper 42 is slightly higher than the height of the nozzle surface 12a. In this state, the inkjet head 12 is moved along the carriage shaft 14, and the tip of the wiper 42 is brought into sliding contact with the nozzle surface 12a. As a result, foreign matter and ink adhering to the nozzle surface 12 a are scraped off by the tip of the wiper 42.

  When the print job is finished and the inkjet head 12 is made to wait at the standby position, the control unit 30 moves the head cap 41 to a position where the edge 41b is in close contact with the periphery of the nozzle surface 12a, thereby blocking the nozzle. As a result, it is difficult to thicken the ink in the nozzles during standby, and clogging and the like are less likely to occur. Further, the control unit 30 can perform a wiping process in which the wiper 42 wipes the nozzle surface 12a by raising the wiper 42 in synchronization with the timing of moving the inkjet head 12 to the standby position side or the printing position side. it can.

  When head cleaning becomes necessary due to nozzle clogging or the like, the control unit 30 operates the pump motor with the head cap 41 moved to the position where the nozzle is blocked, and the recess 41c and the nozzle surface 12a. It is possible to execute an ink suction process for sucking the enclosed space and ejecting ink from each nozzle.

  In addition, the control unit 30 keeps the ink jet head 12 facing the head cap 41 in order to keep the state of the ink droplets in the nozzle appropriately, and from all nozzles of the ink jet head 12, regardless of the printing operation. A flushing process for ejecting a predetermined amount of ink into the recess 41c of the head cap 41 is periodically performed. It is also possible to perform flushing processing at a desired timing to eject a larger amount of ink droplets than the ink droplets ejected by periodic flushing processing at a desired timing, thereby recovering nozzle clogging etc. it can.

  The control unit 30 can perform any one of the wiping process, the ink suction process, the flushing process, or a combination of these processes as a cleaning process, but before performing these processes from the nozzle, A nozzle check process for inspecting the ink ejection state is performed. Based on the result of the nozzle check, it is determined whether or not to perform nozzle cleaning. If necessary, a nozzle cleaning process is performed.

  Next, the head cleaning mechanism 40 is provided with a nozzle check mechanism for detecting defective nozzles. That is, an absorbent material 41d for absorbing the discharged waste ink is disposed in the recess 41c, and a conductive material 41e is attached so as to be electrically connected to the absorbent material 41d. The electrical signal that has flowed through the conductive material 41 e is taken out by wiring or the like and input to the control unit 30. By discharging charged ink droplets from the respective nozzles of the inkjet head 12, it is possible to take out a signal of a current change that occurs when the charged ink droplets land on the absorber 41d. If this signal is equal to or lower than a predetermined threshold value even though ink droplets have been ejected, it can be determined that the nozzle is defective in ejection. In addition, as a method for detecting a defective nozzle, there is a method for detecting ejected ink droplets by optical means such as a laser.

  Specifically, the nozzle check process discharges charged ink droplets from the nozzles of the inkjet head 12, and based on a signal of current change when the ink droplets land on the absorbent 41d in the recess 41c, The ejection state of the ink droplets from is checked. In the nozzle check process, the head cap is set so that the gap L1 between the nozzle surface 12a and the upper end of the edge 41b of the head cap 41 and the gap L2 between the nozzle surface 12a and the surface of the absorbent material 41d have predetermined dimensions. 41 is positioned, and in this state, the inkjet head 12 side is grounded so that the inkjet head 12 and the head cap 41 have a predetermined potential difference, and a voltage is applied to the head cap 41 side to establish a predetermined electric field state. The ink ejected from the inkjet head 12 is charged with a predetermined amount of charge before landing by this electric field. When the ink lands, the charged charge flows through the conductive material 41e. In this way, it is possible to accurately inspect the ejection state of the ink droplets.

(Control system)
Next, FIG. 8 is a schematic block diagram showing a control system of the ink jet printer 1. The control system of the inkjet printer 1 is mainly configured by a control unit 30 including a CPU, a ROM, a RAM, and the like. Print data and commands are supplied to the control unit 30 from a host device such as the host device 32 via the transmission / reception unit 31. The control unit 30 controls the drive of each unit based on a print command from the host device 32 or the like, and executes a paper feeding operation and a printing operation.

  The inkjet head 12 is connected to the output side of the control unit 30 via a head driver 12b. A carriage motor 16 and a paper feed motor 35 are connected via motor drivers 33 and 34. On the input side of the control unit 30, an operation input unit 30a, sensors 2c, 2d, and 2e, reflective photosensors 26 and 29, and a transmissive photosensor 27 are connected. The control unit 30 controls nozzle check processing, head cleaning processing, recording paper transport processing, printing processing, and the like based on the detection output of each sensor.

  Here, the control unit 30 is connected to a storage unit 36 composed of a rewritable nonvolatile memory such as a flash ROM. Here, a recording area is provided which functions as a reliability setting unit 37 capable of setting the reliability of nozzle check by the nozzle check mechanism. Further, the NG information print setting unit 38 and the NG image information registration unit 39 that can set whether or not to print NG information indicating a defective print page or defective print label printed by the defective nozzle, respectively. A recording area is provided.

  When the command supplied from the host device 32 is a reliability setting command, the control unit 30 sets the reliability specified by the reliability setting command in the reliability setting unit 37. For example, if the high reliability is set, the nozzle check is executed in the execution mode in the high reliability mode, and if the medium reliability is set, the nozzle check is executed in the execution mode in the intermediate mode, and the low reliability is set. Then, the nozzle check is executed in the execution form in the no misreading mode L.

  Similarly, when receiving a command for instructing NG information print setting from the host device 32, the control unit 30 sets the NG information print setting unit 38 to perform NG information printing, and subsequently receives NG image information to be received. Register in the registration unit 39. As will be described later, the control unit 30 sets the NG information print setting when a nozzle check is performed and a defective nozzle is detected at the time after the printing of one page of recording paper or the printing of one label is completed. If printing of NG information is set by the unit 38, the registered NG image information is superimposed on a printed page portion or printed label of the recording paper, or a predetermined margin such as a label margin is set. Control to print by adding to the place.

  Further, the control unit 30 corresponds to a condition in which the following defective nozzles are likely to occur frequently in the recording area as a nozzle check execution time setting means, and includes control flags shown in (1) to (4). It is possible to detect that the inkjet printer 1 is in a state corresponding to the frequent occurrence condition of defective nozzles. In addition to these, a condition that the ink viscosity increases at the nozzle surface 12a may be set by detecting an environment of temperature and humidity.

(1) Timer AID flag F1
In order to be able to perform the nozzle check periodically or at a predetermined timing, the control unit 30 uses a built-in timer to indicate that a predetermined time has elapsed since the most recent nozzle check, printing process, or head cleaning process. If detected, the timer AID flag is set. The timer AID flag may be set based on an elapsed time from a predetermined process other than the nozzle check, printing process, and head cleaning process. For example, the timer AID flag may be set when 24 hours have elapsed.

(2) Impact detection flag F2
When the impact sensor 2e detects that a predetermined impact has occurred in the inkjet printer 1, the control unit 30 sets an impact detection flag. If the impact of the inkjet printer 1 is further detected with the impact detection flag already set, the impact detection flag remains set.

(3) Startup processing flag F3
When the power switch of the inkjet printer 1 is turned on, the control unit 30 detects a start signal or a reset signal input from a host device or the like, or a reset signal from the inside of the inkjet printer 1, Start processing or restart processing is performed, and a start processing flag is set.

(4) Cover close flag F4
When the open / close sensor 2c detects that the roll paper cover 2a of the inkjet printer 1 is closed and when the open / close sensor 2d detects that the ink cartridge cover 2b is closed, the control unit 30 sets the cover close flag. set. If the opening / closing of the roll paper cover 2a or the ink cartridge cover 2b is further detected while the cover close flag is already set, the cover close flag is kept set.

  The control unit 30 periodically checks whether each of the above flags is set, and executes a nozzle check when detecting that the flag is set.

(Nozzle check and head cleaning operation control)
FIG. 9 is a schematic flowchart showing the operation of the inkjet printer 1 with a focus on nozzle check and head cleaning operations.

  First, FIG. 9A is a flowchart showing the setting operation of the reliability mode of the nozzle check by receiving a command from the host device 32. When receiving the nozzle check reliability mode setting command “Ex command” from the host device 32 side (step ST1), the control unit 30 of the inkjet printer 1 determines the reliability mode specified by the Ex command as the reliability. Writing to the setting unit 37 (step ST2). For example, by the Ex command, the high reliability mode H indicating the highest reliability with the highest reliability of the nozzle check, the intermediate mode M indicating the intermediate reliability with the medium reliability, and the low reliability with the lowest reliability. It is assumed that a three-stage reliability mode of a misreading-free mode L indicating that it can be set.

  Next, nozzle check and head cleaning operation control of the inkjet printer 1 will be described with reference to a schematic flowchart shown in FIG. First, it is checked whether or not each of the above-described flags F1 to F4 is set (step ST11). If the flag is set, a nozzle check is executed (step ST12). If a defective nozzle that may cause a missing dot or the like is not detected, the process is terminated (step ST13 → ST14).

  When a defective nozzle is detected, the set reliability mode is confirmed (step ST13 → ST15). If the set reliability mode is the high reliability mode H or the intermediate mode M, head cleaning is executed (step ST16). In the case where the set reliability mode is the no misreading mode L, there are three or more defective nozzles detected and two nozzles that are detected and adjacent nozzles. If both are defective nozzles, head cleaning is executed (step ST17 → ST16). If the number of detected defective nozzles is one, and if the number of defective nozzles is two but not adjacent, the process is terminated without performing head cleaning (step ST17 → ST14). The no misreading mode L is a level that places importance on throughput at a level that does not require misreading even if dots are missing in characters or the like. Depending on the degree, even if there are three or more defective nozzles, it may be set so that head cleaning is unnecessary.

  Next, in the label printing, the control unit 30 of the inkjet printer 1 executes an interrupt process for confirming the set reliability mode every time printing of one label 5c is finished (step ST21). ). The end point of printing in the print data is detected based on a command such as a line feed or a page break included in the print data supplied from the host device 32 side. In this case, when the high reliability mode H is set, the process proceeds to step ST12, and as described above, the nozzle check is executed, and based on this, it is determined whether or not the head cleaning is necessary. If so, perform head cleaning. On the other hand, when the intermediate mode M and the no misidentification mode L are set, the process is terminated without performing the nozzle check (step ST21 → ST14). In order to perform it more strictly, the nozzle check may be performed for each row.

  In addition, the control unit 30 of the inkjet printer 1 confirms the set reliability mode after the end of a series of print jobs during label printing, for example, after the end of printing a plurality of labels by batch processing or the like. Interrupt processing is executed (step ST22). The end point of the print job is detected based on a command included in the print data supplied from the host device 32. In this case, if the high-reliability mode H in which the nozzle check is performed every time printing of one label 5c is completed, the process is terminated (step ST22 → ST14), and one label 5c. When the intermediate mode M in which the nozzle check is not performed every time printing is finished and the misreading-free mode L are set, the process proceeds to step ST12, where the nozzle check is performed as described above. Based on this, it is determined whether or not the head cleaning is necessary, and the head cleaning is executed if necessary.

  As described above, in the inkjet printer 1, when the high reliability high-reliability mode H is set as the reliability of the nozzle check, the nozzle check is performed every time the printing operation of each label is completed as an execution form of the nozzle check. A check is being performed. On the other hand, when the intermediate mode M and the no misreading mode L are set with low reliability, the nozzle check is not performed every time one label is printed, and the nozzle check is performed after the end of a series of print jobs. Is only done. Further, in the case of high and medium reliability, head cleaning is always executed when even one defective nozzle is detected. On the other hand, in the case of low reliability, head cleaning is executed only when three or more defective nozzles are detected and when two or more adjacent defective nozzles are detected.

  Therefore, the nozzle check frequency is high when the reliability is high, and the nozzle check frequency is low when the reliability is medium and low. Further, the head cleaning frequency is high in the case of high and medium reliability, and the head cleaning frequency is low in the case of low reliability. As a result, for users who have absolute print quality, by selecting the high reliability mode H, it is possible to reliably prevent nozzle omission and to issue labels with extremely high print quality and high reliability. In addition, for a user who has a print quality that does not cause misreading of characters, the user can issue a printed label in a printing form with high print throughput by selecting the no misreading mode. Furthermore, for example, for a user who wants to guarantee the bar code print quality to a minimum, the user can issue a label in a form in which both the print quality and the print throughput are realized by selecting the intermediate mode.

(Print control operation when the high reliability mode is set)
Next, when the high reliability mode H is set, the nozzle check is executed every time one label 5c is printed as described above. In this case, if printing of NG information is set in the NG information print setting unit 38, a print control operation for NG image information is executed.

  FIG. 10A is a schematic flowchart showing a procedure for registering NG image information. When an “RCC command” which is a command indicating a registration request for NG image information is supplied from the host device 32 side and the control unit 30 confirms the RCC command (step ST31), the NG image sent following the RCC command is sent. Information is registered in the registration unit 39 (step ST32). Similarly, when the control unit 30 receives a command for setting printing of NG image information when there is a defective nozzle from the host device 32 side, the NG information print setting unit 38 is based on this content. In addition, a setting is made to print NG image information when there is a defective nozzle. The setting of the NG information print setting unit 38 may be set from the operation input unit 30a of the inkjet printer 1 or the like.

  FIG. 10B shows the label printing operation when NG image information is registered and the NG information print setting unit 38 is set to print NG image information when there is a defective nozzle. It is a schematic flowchart shown. When the high reliability mode is set, the nozzle check is executed after printing one label 5c (steps ST41, ST42, ST43). When a defective nozzle is not detected, it is determined that printing without nozzle omission has been performed, a transport operation for discharging the printed label is performed, and the process ends (steps ST43 → ST44 → ST45).

  If even one defective nozzle is detected, it is determined that printing of the printed label is defective printing, the label is reversely fed, returned to the printing position by the inkjet head 12, and registered. The NG image information is printed over the printed label (steps ST43 and ST46). A discharge operation is performed to discharge the label after printing the NG image information (step ST47). Thereafter, although illustration is omitted, as described above, head cleaning is executed. Thereafter, the same print information is again printed on the next label, and the nozzle check is performed again (step ST48 → ST42). If a defective nozzle is not detected, a label is issued and the process is terminated (steps ST43, ST44, ST45). The NG image information may be printed in the margin, and the printing position may be set in advance by a command.

  In this way, in this example, when the high reliability mode H is set, it is checked whether defective printing such as missing dots is performed every time one label is printed. If it is determined that the printing is defective, the NG image information is printed on the label on which the defective printing has been performed and is discharged. Therefore, a label on which defective printing has been performed is not used as it is. When defective printing occurs, after performing head cleaning, printing is performed again to reissue labels. Therefore, a normally printed label can always be issued.

(Another example of print control operation when the high reliability mode is set)
In this example, when the high reliability mode H is set, NG image information is printed on a label in a defective print state. Instead, when defective printing is performed, the host device 32 side is notified of this, so that the user can confirm the state of defective printing, and the host device 32 can make a judgment when necessary. Only the label may be reissued.

  FIG. 11 is an operation explanatory diagram showing an example of the processing operation in this case. Describing according to this figure, when the high reliability mode H is set, the control unit 30 performs a nozzle check when the label printing for one sheet is completed (steps ST51 and ST52). If a defective nozzle is not detected, a transport operation for issuing a printed label is performed, and the process ends (steps ST53 → ST54).

  If a defective nozzle is detected, the control state is shifted to a reissue wait state due to defective printing (step ST53 → ST55). Here, the status monitor of the printer driver of the host device 32 is activated, and the status of the inkjet printer 1 is monitored (arrow A1). When a defective nozzle is detected, the control unit 30 transmits a status signal indicating “waiting for reissue” to the host device 32 (arrow A2).

  Upon receiving this status signal, the host device 32 displays a dialog box B on its monitor screen and a message B1 prompting the user to select whether or not to reissue the label. . When the “Reissue” button B2 in the box B is clicked, a reprint request command is transmitted to the control unit 30 via the transmission / reception unit 31 (arrow A3), and the “Do not reissue” button B3 is clicked. Then, an unnecessary reprint command is transmitted to the control unit 30 via the transmission / reception unit 31 (arrow A4).

  Upon receiving a command related to whether reissue is necessary, control unit 30 cancels the reissue wait state and analyzes the command to determine whether reissue is necessary (steps ST56 and ST57). When reissuance is requested, printing and conveying operations for reissuing the label are performed, and the nozzle check is executed again (step ST58 → ST52). If no defective nozzle is detected, it is determined that printing of the reissued label is normal, and the process ends (steps ST53 and ST54). On the other hand, if reissuance is unnecessary, the label determined to be defective printing is discharged, and the process ends (steps ST57 and ST54).

  In this way, when defective printing is performed, by confirming whether or not reissuing is necessary for the user, the user actually confirms the label of the defective printing state and determines whether or not reissuing is necessary. Can do. Since the user can actually confirm the printing state of the label, the user can select whether or not to use the label in the defective printing state as it is. When it is determined that it can be used, re-issuance is unnecessary, so that it is possible to prevent unnecessary label re-issuance for the user. For this reason, useless consumption of labels and ink can be reduced.

  It is also possible to set in advance in the control unit 30 whether or not reissue is performed when defective printing is performed. For example, in the storage area of the storage unit 36, a reprint necessity setting unit that can set whether or not to perform reprinting when defective printing is performed is provided, and the control unit 30 performs label reprinting based on the setting state. You may make it perform printing operation after confirming the necessity of issuing. The setting of the reprint necessity setting unit may be input from the operation input unit 30a of the inkjet printer 1 or may be set by a command from the host device 32 side.

(Other embodiments)
In the above example, the reliability that can be set is three stages, but it may be two stages or four or more stages.

  In addition, although the execution frequency and time are changed as the nozzle check execution mode according to the reliability, other execution modes may be used. For example, nozzle check is performed for all nozzles in the case of high reliability, and nozzle check is performed for every other nozzle in the case of low reliability. It may be possible to shorten it.

  Further, the above example is a case where label paper is used as recording paper, but the present invention can be similarly applied to printing on normal continuous paper. For example, in the case of high reliability, the nozzle check is performed every time one page is printed on continuous paper. In the case of medium or low reliability, the nozzle check is performed when a series of print jobs are completed. What should I do?

1 is an external perspective view of an ink jet printer to which the present invention is applied. It is an external appearance perspective view of the state which opened the inkjet printer. It is a perspective view which shows the printer mechanism part of an inkjet printer. It is a schematic sectional drawing of an inkjet printer. It is explanatory drawing which shows the sensor position on the conveyance path of an inkjet printer. It is a perspective view which shows the head cleaning mechanism of an inkjet printer. It is explanatory drawing which shows the nozzle check state of a head cleaning mechanism. It is a schematic block diagram which shows the control system of an inkjet printer. It is a schematic flowchart which shows the operation | movement of a nozzle check and head cleaning. It is a schematic flowchart which shows the printing operation of NG image information at the time of defective printing. It is operation | movement explanatory drawing which shows the label reissue operation | movement by a user selection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer, 2 exterior case, 3 discharge port, 4 roll paper storage part, 5 roll paper, 5a recording paper, 5b peeling mount, 5c label, 5d black mark, 6 ink cartridge, 7 cartridge mounting part, 8 recording paper Cutting mechanism, 10 printer mechanism, 11 printing mechanism, 12 inkjet head, 12a nozzle surface, 13 carriage, 14 carriage shaft, 15 endless belt, 16 carriage motor, 17 back pressure adjustment unit, 18 damper unit, 19 ink supply tube, 20 Platen, 21 Rear paper feed roller, 22 Rear paper press roller, 23 Front paper feed roller, 24 Front paper press roller, 25 Tension guide, 26, 29 Reflection type photo sensor, 27 Transmission type photo sensor, 30 Control unit 30a Operation input unit, DESCRIPTION OF SYMBOLS 1 Transmission / reception part, 32 Host apparatus, 33, 34 Motor driver, 35 Paper feed motor, 36 Memory | storage part, 37 Reliability setting part, 38 NG information print setting part, 39 Registration part, 40 Head cleaning mechanism, 41 Head cap, 41a Sealing surface, 41b edge, 41c recess, 41d absorbent, 41e conductive material, 42 wiper, 43 ink suction part, 44 frame

Claims (9)

Nozzle check means for detecting whether the nozzle of the inkjet head is a defective nozzle,
Reliability setting means capable of setting the reliability of nozzle check by the nozzle check means;
Control means for executing the nozzle check by the nozzle check means in an execution form preliminarily associated with the set reliability based on the set reliability set in the reliability setting means. An ink jet printer characterized by comprising: The inkjet printer according to claim 1, wherein
2. An ink jet printer according to claim 1, wherein at least two types of reliability of high reliability and low reliability can be set in the reliability setting means. The inkjet printer according to claim 2, wherein
When the set reliability is the high reliability, the control means performs the nozzle check every time predetermined printing on the recording paper is completed, and when the set reliability is the low reliability. An ink jet printer that performs the nozzle check after a predetermined print job is completed. In the inkjet printer according to any one of claims 1 to 3,
Having nozzle check execution time setting means capable of setting the nozzle check execution time by the nozzle check means;
The ink jet printer according to claim 1, wherein the control means executes the nozzle check at an execution time set by the nozzle check execution time setting means. The inkjet printer according to claim 4.
The inkjet check execution time set by the nozzle check execution time setting means is at least one of the following (1) to (4).
(1) When the power of the ink jet printer is turned on (2) When the open / close cover is closed When the open / close cover is closed (3) When the shock detection means for detecting the shock applied to the ink jet printer is provided When printing is started after the impact is detected by the impact detection means (4) When a predetermined time has elapsed from the previous nozzle check execution time In the inkjet printer according to any one of claims 1 to 5,
A head cleaning means for recovering the defective nozzle;
The control unit determines whether or not to perform head cleaning by the head cleaning unit based on a result of the nozzle check and the set reliability set in the reliability setting unit after the nozzle check is executed. An ink jet printer characterized by the above. In the ink jet printer according to any one of claims 1 to 6,
NG information print setting means capable of setting whether or not to print NG information indicating defective printing,
The control means is set to print the NG information by the NG information print setting means when the nozzle check is executed after the predetermined printing on the recording paper is completed and the defective nozzle is detected. If it is, the NG information is printed on the recording paper. In the ink jet printer according to any one of claims 1 to 6,
It has a communication means for transmitting to the upper device that the defective printing has been performed and receiving an instruction on the necessity of reprinting from the upper device.
When the nozzle check is performed after the predetermined printing on the recording paper is completed and the defective nozzle is detected, the control unit transmits the fact that the defective printing has been performed by the communication unit, and An ink jet printer that causes a predetermined printing on the recording paper to be performed when a command for requesting reprinting is received by the communication unit. In the ink jet printer according to any one of claims 1 to 6,
Re-printing necessity setting means capable of setting necessity of re-printing when defective printing is performed,
The control unit is configured to request the reprinting necessity setting unit to perform the reprinting when the nozzle check is performed and the defective nozzle is detected after predetermined printing on the recording paper is completed. If so, an ink jet printer that performs predetermined printing on the recording paper.

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