JP5040283B2 - Recording method and recording apparatus in recording apparatus - Google Patents

Description

  In the present invention, for example, in a recording apparatus such as a serial printer, the recording unit moving operation is started before the recording medium conveying operation is stopped, and the recording medium conveying operation and the recording unit moving operation are superposed. The present invention relates to a recording method and a recording apparatus.

  Conventionally, in a recording apparatus such as a serial printer, in order to shorten the printing processing time, a superimposing process for superimposing a paper feeding operation and a carriage operation has been performed (for example, Patent Documents 1 and 2). In the superposition process, first, when the printing process for one pass is completed, the paper feed motor (PF motor) is activated to feed the paper. Thereafter, the carriage motor (CR motor) is activated at a predetermined timing to move the carriage before the driving of the PF motor is completed. Thereby, the printing operation can be started almost simultaneously with the end of paper feeding. Accordingly, it is possible to shorten the printing processing time compared to the configuration in which the CR motor is activated after the paper feed is finished to start the carriage movement.

  By the way, if a sheet whose paper conveyance direction length is shorter than the set value is mistakenly fed, at least a part of the sheet does not exist at the recording target position of the recording head after feeding and the printing operation is performed as it is. There is a problem that paper that is printed on the platen and slides on the platen is stained with ink. In order to solve this problem, for example, in Patent Document 1, a time based on the distance from the paper detection sensor to the recording head is secured as the time from the start of the carriage to the start of printing. A configuration is disclosed in which platen printing is not performed even if the carriage is activated and printing is performed before the end. However, it is necessary to secure a time based on the distance from the paper detection sensor to the recording head, and platen printing is prevented at the expense of printing processing time.

On the other hand, for example, in Japanese Patent Application Laid-Open No. H11-228707, when a sheet whose paper conveyance direction length is shorter than a set value is fed, the trailing edge of the sheet deviates from the recording position of the recording head toward the downstream side in the conveyance direction when the paper feeding is completed. A recording apparatus is disclosed in which if it is determined whether or not to depart, even if the carriage is already activated at that time, a printing non-permission instruction is issued to stop the printing operation. That is, the remaining amount of the override area (printable range) and the remaining paper feed amount of the PF motor are obtained based on the count value of the override counter activated after the trailing edge of the paper passes the paper detection sensor. When it is determined that the paper feed remaining amount is greater than or equal to the remaining amount in the override area, a print non-permission command is generated. For this reason, when the trailing edge of the paper passes the recording position of the recording head, the printing operation is stopped by the printing non-permission command, so that platen printing is prevented without sacrificing the printing processing time. Also, the calculation processing for the above determination to prevent platen printing is started when the override counter is turned on (that is, the trailing edge of the paper is detected) and a CR motor activation signal is received. It was.
JP 2006-212923 A (for example, paragraphs [0030] to [0042] of the specification, FIGS. 4 to 11) JP 2001-232882 (for example, paragraphs [0070] to [0077] of the specification, FIGS. 5 and 6)

  However, in Patent Document 2, although platen printing can be prevented, the determination process is started with a trigger when the override counter is turned ON and a CR motor activation signal is received. That is, the reception of the CR motor activation signal is an essential condition for starting the determination process. For this reason, the determination process is started almost simultaneously with the activation of the carriage, and the print disapproval command is always issued after the carriage is activated. For example, when the movement time from the start of the carriage to the print start position is short, the determination result of the print non-permission determination may be delayed and the print operation may be started. In addition, the determination process is performed after the CR motor is started, and the print disapproval command is always executed after the carriage has moved. Therefore, when the print is disallowed, the carriage always runs idle without a print operation. . Such a free running operation of the carriage is an unnatural operation of the printer, and is not preferable from the viewpoint of power consumption and motor life because the CR motor is driven wastefully, but it is preferable to reduce it. According to this determination processing method (recording method), there is no room for adopting a method of reducing the idle running operation of the carriage.

  The present invention has been made to solve the above-mentioned problems, and its object is to determine whether or not recording can be continued at the position of the recording medium at the end of conveyance when the detecting means detects the trailing edge of the recording medium. Recording method in a recording apparatus that can more reliably prevent an improper printing operation such as platen printing from being performed despite a determination that recording cannot be continued due to a delay in the determination result And providing a recording apparatus.

  The present invention includes a first drive source that is driven to convey a recording medium, a second drive source that is driven to move a recording unit that performs recording on the recording medium, the first drive source, and a second A recording method in a recording apparatus that controls a driving source so that the conveyance and recording are alternately performed, and activates the second driving source before stopping the driving of the first driving source in the control, A detecting step of detecting the trailing edge of the recording medium by a detecting means at a position upstream of the recording position of the recording means; and when the detecting means detects the trailing edge, the recording medium at the time of detection of the trailing edge A determination step for determining whether or not recording can be continued at the position of the recording medium at the end of the current transport based on the remaining transport amount; and when it is determined in the determination step that recording cannot be continued, Inspection If the start timing of the second drive source has come before the time point, the recording means performs a recording stop process after the second drive source is started, while the second drive source is detected after the detection time of the rear end. The gist of the invention is that it includes a control step of starting the second drive source when the start timing of the source comes, or stopping the start of the second drive source or stopping the recording by the recording means.

  According to this, when the trailing end of the recording medium is detected by the detecting unit at a position upstream of the recording position of the recording unit in the detecting step, the remaining transport amount of the recording medium at the time of detecting the trailing end is determined in the determining step. Based on this, it is determined whether or not recording can be continued at the position of the recording medium at the end of the current conveyance. If it is determined in the determination step that recording cannot be continued, if the start timing of the second drive source has come before the trailing edge detection time in the control step, recording by the recording means after the start of the second drive source is performed. Is canceled. On the other hand, if the start timing of the second drive source comes after the trailing edge detection time, the start of the second drive source is performed although the start of the second drive source is stopped or the recording by the recording means is stopped. However, when the second drive source is started although the recording by the recording unit is stopped, the stop of the recording is determined before the second drive source is started. Therefore, when the start timing of the second drive source comes after the trailing edge detection time, the recording stop process by the recording unit is performed early before the start of the second drive source. For example, it is easier to reliably avoid the inconvenience that the recording is started in spite of the fact that the recording should be stopped, but the recording is not started in time.

  In the recording method of the present invention, if it is determined in the control step that recording cannot be continued in the determination step, the start timing of the second drive source has come before the detection time of the rear end. Then, after the second drive source is activated, the recording means performs a recording stop process. On the other hand, if the second drive source activation timing comes after the detection time of the rear end, the second drive source is activated and the second drive source is activated. It is preferable to stop the recording by the recording means.

  According to this, in the control step, when it is determined that the recording cannot be continued in the determination step, if the start timing of the second drive source has come before the trailing edge detection time, that is, after the start of the second drive source, that is, After the start of movement of the recording means, recording stop processing by the recording means is performed. For this reason, although the recording means moves, recording is not performed. On the other hand, if the start timing of the second drive source comes after the trailing edge detection time, both the start of the second drive source and the recording by the recording means are stopped. For this reason, not only recording by the recording means is not performed, but also movement (idle running) without recording by the recording means can be avoided.

  In the recording method of the present invention, if it is determined in the control step that recording cannot be continued in the determination step, the start timing of the second drive source has come before the detection time of the rear end. When the second drive source is activated, the recording unit performs recording cancellation processing. On the other hand, if the second drive source activation timing comes after the detection time of the rear end, the recording unit performs recording cancellation processing. Is preferably performed before the second drive source is activated, and then the second drive source is activated when the activation timing is reached.

  According to this, when it is determined in the determination step that recording cannot be continued, if the start timing of the second drive source has come before the detection time of the trailing edge, recording is performed after the start of the second drive source in the control step. Recording stop processing by means is performed. On the other hand, if the start timing of the second drive source comes after the detection time of the rear end, in the control step, the recording stop process by the recording means is performed before the start of the second drive source, and then the start timing comes. The second drive source is activated. For this reason, when recording is stopped, the recording means always runs idle, but no extra control is required to stop the movement of the recording means that does not affect the platen printing.

In the recording method of the present invention, it is preferable that the recording means is configured to be able to start recording in the middle of acceleration in the movement process.
According to this, even when the recording means starts recording in the middle of acceleration in the movement process, if the start timing of the second drive source comes after the trailing edge detection time, the recording stop process is performed before the recording means starts moving. The frequency of cancellation processing performed early is increased. For this reason, it is easier to prevent the inconvenience that the recording stop processing is not completed in time and the recording is started, and this is particularly effective in a configuration in which printing during acceleration is performed with a short movement time from the start of movement of the recording means to the recording start position. .

  In the recording method of the present invention, the recording means is provided in a movable body that is movable in a direction different from the conveyance direction of the recording medium, and the movement of the movable body is started by the activation of the second drive source. In addition, the second driving source is connected to a supply unit that is operated by the moving body that has been moved to a predetermined position on the moving path of the moving body and that conveys the recording medium when it is supplied. Clutch means, and when it is determined that recording cannot be continued, when the activation of the second drive source for recording is stopped, the second drive source is activated to bring the clutch means into a connected state. The moving body is preferably moved to the predetermined position.

  According to this, when it is determined that the recording cannot be continued and the activation of the second drive source (that is, the activation of the moving body) is stopped, if there is a recording medium to be supplied next, that recording medium should be supplied. The second drive source is activated to move the moving body to a predetermined position. For this reason, when the recording cannot be continued, the moving body can immediately start moving to a predetermined position without running idle, so that the supply of the next recording medium can be started early. As a result, the printing operation on the next recording medium can be started at an early stage, which contributes to an improvement in throughput.

  In the recording method of the present invention, the determination as to whether or not the recording can be continued in the determining step is performed by conveying the rear end of the recording medium from a position at the time of detection to a limit position where recording by the recording unit is possible. It is preferable to compare the initial override amount corresponding to the distance with the remaining transport amount of the recording medium when the trailing edge is detected.

  According to this, in the determination step, the initial override amount corresponding to the transport distance in which the rear end of the recording medium is transported from the position at the time of detection to the limit position where recording by the recording means can be performed, and the recording medium at the time of detecting the rear end It is determined whether or not recording can be continued by comparing the remaining transport amount.

  In the recording method of the present invention, after the conveyance when the detection means detects the rear end, the rear end is located in an override region from the position at the time of detection to the limit position. In the next and subsequent transports that start from the state where the trailing edge is located in the override area after the recorded recording, instead of the determination step, the recording medium at the end of the current transport after the next time is recorded. A second determination step for determining whether or not recording can be continued at the position, and in the second determination step, when a request to move the recording unit for recording is received, the conveyance start located in the override area is started. The amount of recording corresponding to the transport distance of the recording medium is compared with the transport amount corresponding to the transport distance by which the trailing end of the time is transported to the limit position, and the recording at the end of the current transport It is preferable to determine whether the recording continuability at the location of the body.

  According to this, after the end of conveyance when the detecting means detects the trailing edge, after recording performed in a state where the trailing edge is located in the override area from the position at the time of detection to the limit position, In the next and subsequent transports starting from the state where the rear end is located, the second determination step replaces the determination step, and the recording medium at the end of the first (current) transport in the subsequent and subsequent times. It is determined whether or not the recording can be continued at the position. In the second determination step, upon receiving a request to move the recording means for recording, an override amount corresponding to a transport distance in which the rear end at the start of transport positioned in the override region is transported to the limit position; It is determined whether the recording can be continued at the position of the recording medium at the end of the current conveyance by comparing the current conveyance amount of the recording medium. Accordingly, the above determination is triggered by the reception of a request to move the recording means for recording, so that the determination result as to whether or not recording can be continued is made before the second drive source is activated (that is, recording is performed). Before the movement of the means).

  The present invention provides a first drive source that is a drive source of a conveyance unit that conveys a recording medium, a second drive source that is a drive source of a moving unit that moves a recording unit that performs recording on the recording medium, and the first drive. Control means for controlling the source and the second drive source so that the conveyance and the recording are alternately performed, and for starting the second drive source before stopping the driving of the first drive source in the control. In the recording apparatus, a detection unit that detects a rear end of the recording medium at a position upstream of the recording position of the recording unit, and the rear end when the rear end of the recording medium is detected by the detection unit. The initial override amount corresponding to the transport distance from the position at the time of detection to the limit position where recording on the recording medium by the recording means is possible is compared with the remaining transport amount of the recording medium at the time of detecting the trailing edge. Determine if you can continue And determining means that, when the determining means determines that recording cannot be continued, if the start timing of the second drive source has come before the detection time of the rear end, the recording means On the other hand, if the start timing of the second drive source comes after the detection time of the trailing edge, the start of the second drive source is stopped or the recording by the recording means is stopped. However, the gist is to activate the second drive source. According to this, the same effect as the invention of the recording method can be obtained.

  Hereinafter, an embodiment in which the present invention is applied to a printer as a recording apparatus will be described with reference to FIGS. FIG. 1 is a schematic perspective view of the printer. However, the outer case of the printer is shown in a removed state.

  As shown in FIG. 1, a printer 10 as a recording apparatus includes a main body case 10a in an exterior case (not shown). The main body case 10a is provided with a carriage 12 guided by a guide shaft 11 and capable of reciprocating in the main scanning direction (X direction in the figure). The carriage 12 is fixed to a part of an endless timing belt 14 that is rotationally driven by driving a carriage motor (hereinafter referred to as a CR motor 13), and the carriage is driven by forward and reverse rotation of the CR motor 13. 12 reciprocates in the main scanning direction X. In the present embodiment, a DC motor is used as the CR motor 13, but a stepping motor can also be used.

  Below the carriage 12, an ink jet recording head 15 is provided as recording means. A black ink cartridge 16 for supplying ink to the recording head 15 and a color ink cartridge 17 are detachably loaded on the carriage 12. The lower surface of the recording head 15 is a nozzle forming surface on which a plurality of nozzles are formed for each ink color.

  The recording head 15 incorporates one piezoelectric vibrator (not shown) for each nozzle. The piezoelectric vibrator corresponding to the nozzle to be ejected with ink droplets vibrates due to the electrostrictive action based on the application of the pulse voltage, and the ink chamber provided for each nozzle in the recording head 15 expands and compresses. Ink droplets are ejected (discharged) from each nozzle.

  The both ends of the moving range in which the carriage 12 reciprocates in the main scanning direction X along the guide shaft 11 are accelerated or decelerated by the carriage 12 that is decelerated for reversing the moving direction or accelerated after the reversing. It is an area. In this embodiment, printing during acceleration in which recording (printing) is started by the recording head 15 is performed from the middle of acceleration before the carriage 12 reaches the constant speed traveling region, and printing during deceleration that continues printing until the middle of deceleration is also performed. Done. Of course, it is possible to adopt a configuration in which printing is performed only in the constant speed traveling region. In the present embodiment, the moving unit is configured by the guide shaft 11, the carriage 12, the timing belt 14, and the like provided for moving the recording head 15 as the recording unit.

  Below the carriage 12, for example, a flat platen 19 that defines the gap (gap) between the recording head 15 and the paper 18 is arranged in a state where the longitudinal direction thereof coincides with the axial direction of the guide shaft 11. In FIG. 1, the right end position of the carriage 12 in the main scanning direction movement range is set as the home position of the carriage 12. At a position corresponding to the home position, a maintenance device 20 is provided for cleaning the recording head 15 and the like while the carriage 12 is moved to the home position side. Further, a waste liquid tank 21 in which the waste liquid discharged from the maintenance device 20 is stored is disposed below the platen 19.

  A paper feed motor (hereinafter referred to as PF motor 22) is disposed at the lower right end of the main body case 10a in FIG. The paper 18 is fed by the rotation of a paper feed roller (none of which is shown) to which the driving force of the PF motor 22 is transmitted via the clutch means, and is similarly transported by the transport roller 24 (FIG. 2) driven by the PF motor 22. The sheet is conveyed (paper fed) in the sub-scanning direction Y while being sandwiched between the two (see). A printing operation (recording operation) performed while ejecting ink droplets from the recording head 15 during the movement of the carriage 12 in the main scanning direction X and a paper feeding operation in the sub-scanning direction Y of the paper 18 are alternately performed. As a result, printing is performed on the paper 18. The printer 10 is provided with a linear encoder 23 along the guide shaft 11. The linear encoder 23 outputs a number of pulses proportional to the moving distance of the carriage 12, and the speed control and position control of the carriage 12 are performed based on the moving position, moving speed, and moving direction of the carriage 12 obtained using the output pulses. Is done.

  FIG. 2 is a schematic side view showing the recording head and the transport mechanism. As shown in FIG. 2, below the recording head 15, a conveying roller 24 (paper) that constitutes the conveying means is disposed at a position before and after the recording position (or platen 19) of the recording head 15 in the conveying direction of the paper 18. A feed roller) and a paper discharge roller 25 are arranged in a rotatable state. The transport roller 24 is configured as a pair including a driving roller 24A and a driven roller 24B, and the paper discharge roller 25 is configured as a pair including a driving roller 25A and a driven roller 25B. The paper 18 is sandwiched between at least one of the rollers 24A and 24B and the rollers 25A and 25B, and the driving force of the PF motor 22 (see FIG. 1) is transmitted to rotate the driving rollers 24A and 25A. By being driven, it is conveyed in the left direction (sub-scanning direction Y) in FIG. Note that a paper feed roller (not shown) provided at a position upstream of the transport roller 24 in the paper transport direction is switched to a connected state when the carriage 12 moves to a predetermined position on the movement path, for example. The driving force of the PF motor 22 is transmitted through the clutch means.

  A paper detection sensor 26 is provided at a position slightly upstream of the transport roller 24 in the paper transport direction. The paper detection sensor 26 includes, for example, a contact type sensor (switch type sensor), and the contact type detection unit (for example, a detection lever) is disposed so as to be able to interfere with the paper 18 on the conveyance path. The paper detection sensor 26 is turned on when the leading end of the fed paper 18 hits the detection unit and displaces it, and the rear end of the paper 18 passes through the detection unit, and the detection unit returns to its original position (standby position). It is configured to turn off when it returns. Of course, as long as the paper detection sensor 26 can detect the paper 18, another type of sensor can be substituted, and for example, an optical sensor (photo sensor) may be employed.

  After the trailing edge of the paper 18 cuts the detection unit of the paper detection sensor 26 and enters a detection state where there is no paper, an override region OR is set as a range in the paper feed direction (conveyance direction) that can be printed. In the present embodiment, for example, a range from the detection position (the position of the detection unit) of the paper detection sensor 26 to the nozzle position (most upstream nozzle position) in the transport direction among the plurality of nozzles formed in the recording head 15 is defined. It is set as the override area OR. For example, when a sheet 18 having a length shorter than the setting (printing condition setting) is being fed, the trailing end of the sheet 18 after the end of sheet feeding may deviate from the override area OR to the downstream side in the conveying direction. sell. In this case, when printing by the recording head 15 is started as it is after paper feeding, printing (ink droplet ejection) is performed on the platen 19 and then the paper 18 sliding on the platen 19 becomes dirty. In order to prevent such platen printing, the position (paper state) of the paper 18 is managed even after the rear end of the paper 18 enters the override area OR. Details of the management method will be described later.

  FIG. 3 shows the main part of the linear encoder, (a) is a cross-sectional view, and (b) and (c) show output signals. As shown in FIG. 3A, the linear encoder 23 includes, for example, a tape-shaped code plate 27 in which 180 slits 27a are formed at equal intervals in one inch (25.4 mm), and a sensor 28. Become. As shown in FIGS. 1 and 5, the code plate 27 is stretched so as to be parallel to the main scanning direction (carriage traveling direction) on the rear side of the traveling area of the carriage 12.

  The sensor 28 shown in FIG. 3 includes a light emitting element 29 and a light receiving element 30 that are arranged to face each other with the code plate 27 interposed therebetween. The light emitting element 29 has a pair of light emitting portions 29a and 29a, and the light receiving element 30 is a pair of light receiving portions 30a and 30a arranged in the main scanning direction X with an interval equal to the interval between the light emitting portions 29a and 29a. have. Each light emitting part 29a, 29a and each light receiving part 30a, 30a are located opposite to each other, and the distance between the pair of light receiving parts 30a, 30a in the slit arrangement direction (code plate longitudinal direction) is from each light receiving part 30a, 30a. The respective pulses ES1 (A phase) and ES2 (B phase) shown in FIGS. 3B and 3C that are output are set to values that are shifted by 90 degrees. The linear encoder 23 outputs a number of pulses corresponding to the number of intermittent light passing through the slits 27 a as the carriage 12 scans.

  When the CR motor 13 rotates forward, that is, when the carriage 12 moves forward in the main scanning direction, the phase of the pulse ES1 advances by 90 degrees from the pulse ES2 as shown in FIG. When the carriage 12 moves backward in the main scanning direction, the phase of the pulse ES1 is delayed by 90 degrees from the pulse ES2 as shown in FIG. One period T of the pulses ES1 and ES2 corresponds to the slit interval (for example, 1/180 inch (= 1/180 × 2.54 cm)) of the code plate 27 and is equal to the time for the carriage 12 to move the slit interval. .

  The printer 10 is provided with a rotary encoder 42 (see FIG. 5) for detecting the rotational position and rotational speed of the PF motor 22 and the like. The encoder 42 has the same configuration as that of the linear encoder 23 except that the code plate 27 in the linear encoder 23 is a rotating disk that rotates in accordance with the rotation of the PF motor 22, and outputs two output pulses ES3 and ES4. The code plate (rotary disk) of the encoder 42 is provided so as to be integrally rotatable with the drive shaft of the transport roller 24, for example. In the printer 10, the slit interval of the plurality of slits provided on the code plate of the encoder 42 for the PF motor 22 is 1/180 inch (= 1/180 × 2.54 cm). Is rotated by one slit interval, the paper is fed by 1/1440 inch (= 1/1440 × 2.54 cm).

  FIG. 5 is a schematic configuration diagram illustrating an electrical configuration of the printer 10. The printer 10 includes a CPU 31, an ASIC 32 (Application Specific Integrated Circuit), a DC unit 33, a PROM 34, a RAM 35, an EEPROM 36, and an I / F 37 (interface). The ASIC 32 exchanges various data (print data, etc.) with the host computer (for example, personal computer) 38 via the I / F 37. The ASIC 32 controls the print resolution, the drive waveform of the recording head 15 and the like based on the print data transmitted from the host computer 38.

  Further, the CPU 31 controls the entire apparatus of the printer 10, and based on print data fetched from the host computer 38 via the I / F 37 and the ASIC 32, activation of the CR motor 13 and PF motor 22, travel schedule (drive schedule), and recording. Each print schedule of the head 15 is set. Then, the CPU 31 drives and controls the recording head 15 via the head driving circuit 39 according to the set printing schedule. Further, the CPU 31 outputs a command signal based on these activation and travel schedules to the DC unit 33.

  The DC unit 33 controls the driving of the CR motor 13 via the CR motor driving circuit 40 and the PF motor 22 via the PF motor driving circuit 41 based on the command signal. When the carriage is driven, the DC unit 33 inputs the pulse signals ES1 and ES2 from the linear encoder 23, and calculates the moving speed, moving direction, and position of the carriage 12. Further, the DC unit 33 inputs pulse signals ES3 and ES4 from the encoder 42 at the time of paper feeding, and calculates the driving position, driving speed (paper feeding position, paper feeding speed) and the like of the PF motor 22.

  The CPU 31 performs control (CR-PF overlay control) to superimpose the carriage operation and the paper feed operation so that the printing operation of the recording head 15 is started immediately after the paper feed is completed. The activation of the CR motor 13 and the PF motor 22 and the travel schedule are created so as to satisfy the above. When this superposition control is performed, when the paper 18 whose paper transport direction length is shorter than the set length is fed, the carriage operation is started before the paper feed is finished, so that the carriage 12 reaches the print start position. There may be a case where at least a part of the paper 18 does not exist at the print target position of the recording head 15 when the printing operation is started. In this case, if the printing operation is performed as it is, printing is performed on the platen 19. Therefore, in this embodiment, it is determined whether or not there is a sheet at the print target position in order to avoid platen printing that induces smearing of the sheet 18. If the paper is not part, control (platen printing prevention processing) is performed to stop the printing operation.

  The PROM 34 stores speed tables (acceleration table and deceleration table) (not shown) for carriage speed control and paper feed speed control, which are referred to for speed control of the CR motor 13 and the PF motor 22, respectively. Yes. The speed table is a table showing the relationship between the position and a target value (encoder pulse period in this example) corresponding to the position. In the present embodiment, the carriage speed control is performed by feedback control in which a target value corresponding to the carriage position is acquired by referring to the speed table, and an actually measured value (detection cycle) is brought close to the target value (target cycle). The paper feed speed control is also performed by feedback control in which a target value corresponding to the paper feed position is acquired by referring to the speed table, and the actual measurement value is similarly brought close to the target value. Of course, feed-forward control can also be employed as the speed control.

  Further, a timer IC 43 is connected to the CPU 31, and the CPU 31 inputs a timer signal from the timer IC 43 every predetermined time (for example, a value within a range of several tens to several hundreds μsec.). The CPU 31 executes timer interrupt processing every time a timer signal is input.

  The RAM 35 temporarily stores program data executed by the CPU 31, various data that are the calculation results and processing results by the CPU 31, and various data processed by the ASIC 32. In addition, the RAM 35 is provided with a predetermined storage area that functions as a buffer for storing print data, data being processed, and processed data. The EEPROM 36 stores a firmware program and the like.

  FIG. 6 is a block diagram showing a platen printing preventing apparatus. The control unit 50 is constructed by the CPU 31 executing a firmware program or the like. The control unit 50 includes a sequence control unit 51, a PF motor driver 52, a CR motor driver 53, and a head driver 54. The sequence control unit 51 issues instructions (requests) to the PF motor driver 52, the CR motor driver 53, and the head driver 54 according to the sequence in order to perform a paper feeding operation, a printing operation / paper feeding operation, and a paper discharging operation.

  The PF motor driver 52 performs various calculation processes necessary for performing drive control including speed control (for example, PID control) and stop position control of the PF motor 22 driven for paper feed, paper feed, and paper discharge. I do. The CR motor driver 53 performs various arithmetic processes necessary for performing drive control including speed control and stop position control of the CR motor 13 driven to move the carriage 12. The head driver 54 performs various arithmetic processes necessary to determine the ejection timing for ejecting (fire) droplets from the recording head.

  The PF motor driver 52 includes a calculation unit 55, and the calculation unit 55 includes an overlay calculation unit 55A and a monitoring unit 55B. The overlay calculation unit 55A, which is one of the characteristic parts in this embodiment, activates the CR motor 13 before stopping the driving of the PF motor 22, and superimposes the paper feed operation and the carriage drive operation. CR-PF overlay calculation is performed to calculate the start-up time. Further, the monitoring unit 55B indicates that the actual conveyance direction length (for example, A5 size) of the paper 18 is shorter than the set length (for example, A4 size), and the trailing edge of the paper 18 is the reference position of the recording head 15 at the end of paper feeding. When passing (for example, the most upstream nozzle position), monitoring is performed so that the ink droplets are not ejected (fired) as they are and the platen 19 is not soiled. That is, when the paper detection sensor 26 switches from “paper present” to “paper absent” detection state and the trailing edge of the paper 18 is detected, the monitoring unit 55B detects the initial override amount SORint and the paper at the trailing edge detection time. A comparison is made with the amount of remaining feed SRpf. If the paper feed remaining amount SRpf is larger than the initial override amount SORint (SRpf> SORint), the trailing edge of the paper 18 deviates from the override area at the end of paper feed, and at least one of the paper 18 is at the recording position of the recording head 15. It is determined that there is no paper in the “paper out state”. If it is determined that there is no paper, the monitoring unit 55B stops the ejection (fire) of ink droplets from the recording head 15.

  The monitoring unit 55B manages three states of the paper 18 including the “paper out state”. That is, “paper is present” in which the paper 18 is detected by the paper detection sensor 26, and after the trailing edge of the paper 18 is detected by the paper detection sensor 26, the trailing edge is in the override area OR that can be printed by the recording head 15. There are three “override” states, “no paper” in which the rear end of the paper 18 deviates from the override area OR to the downstream side in the transport direction and at least a portion not printed on the paper 18 occurs. If the managed paper state is “no paper”, a print stop command for stopping the printing is output to the head driver 54. In this embodiment, the output timing of this print stop command may be before or after the carriage 12 is started.

  The motor control unit 44 built in the DC unit 33 outputs a command signal based on an instruction from the PF motor driver 52 to the PF motor drive circuit 41 and drives a command signal based on an instruction from the CR motor driver 53 to drive the CR motor. Output to the circuit 40. The motor control unit 44 includes a PF counter 56, an override counter 57 (OR counter), and a CR counter 58. The PF counter 56 is reset when the driving of the PF motor 22 is started, and increments based on the output pulse of the encoder 42 to count the paper feed amount Spf from the start of paper feed to the current time. The override counter 57 sets the initial override amount SORint when the paper detection sensor 26 detects the trailing edge of the paper 18 and performs a decrementing process based on the output pulse of the encoder 42 so that the trailing edge of the paper 18 is overridden. The remaining amount (override amount) until the end position (limit position) in the transport direction of the region OR is counted.

  The CR counter 58 has two types of counters that perform counting processing based on the output pulses of the linear encoder 23, and indicates the relative position from the movement start position of the carriage 12 and the position from the origin on the movement path, respectively. Count. One of the CR counters 58 increments the count value when the carriage moves forward, decrements the count value when the carriage moves backward, and a position from the origin position (for example, home position) of the carriage 12 based on the obtained count value. Can be grasped. At this time, the moving direction of the carriage 12 is grasped based on the difference in the phase advance of the A phase (SE1) and the B phase (SE2) included in the output pulse of the linear encoder 23 by the CPU 31. Specifically, as shown in FIG. 3B, if the B-phase pulse is at the L level when the A-phase rising edge is detected, as shown in FIG. If the B-phase pulse is at the H level when the rising edge of the A-phase is detected, it is recognized that the direction is reverse (reverse). The relative position from the movement start position of the carriage 12 obtained as the count value of the other one of the CR counters 58 obtains a target value with reference to speed data (not shown) during carriage speed control. And is used for stop position control for stopping the carriage 12 at a predetermined position.

  Further, the motor control unit 44 shown in FIG. 6 measures the period by measuring the time between the edges of the input pulse from the linear encoder 23. This measurement cycle is used as an actual measurement value (detection cycle) in feedback control for controlling the speed of the carriage 12.

  The print control unit 45 outputs a command signal based on an instruction from the head driver 54 to the head drive circuit 39. The print control unit 45 includes a counter 59. The counter 59 performs a counting process based on the output pulse of the linear encoder 23 (specifically, a pulse having a cycle obtained by multiplying the cycle of the output pulse), and counts the relative position from the movement start position of the carriage 12 (that is, the recording head 15). To do. The head driver 54 obtains the print start position as a distance from the movement start position of the carriage 12 based on the print data, and instructs the print control unit 45 to print together with the print start position. When the count value of the counter 59 reaches the print start position after the carriage 12 is activated, the print control unit 45 causes the recording head 15 to start ejecting ink droplets (fire) via the head drive circuit 39. Further, the print control unit 45 generates an ejection timing signal (pulse) having a period proportional to the period of the output pulse (multiplying the period) based on the output pulse of the linear encoder 23, and ink droplets based on the ejection timing signal. Is determined, the printing during acceleration and the printing during deceleration are performed at a constant printing pitch (dot pitch). The drivers 52 and 53 can acquire the count values of the corresponding counters 56 to 58 from the DC unit 33, and are used for various arithmetic processes for calculating command values such as speed control (for example, PID control).

  Next, the calculation contents of the overlay calculation unit 55A in the PF motor driver 52 will be described with reference to FIG. FIG. 4 is a diagram schematically showing the speed waveform of the PF motor 22 and the speed waveform of the CR motor 13. In the graph of the figure, the horizontal axis indicates time and the vertical axis indicates speed. The overlay calculation unit 55A performs acceleration time measurement processing, distance calculation processing, movement time calculation processing, and paper feed amount calculation processing as overlay optimization calculation processing. Then, by this overlay optimization calculation process, the CR start timing for optimizing the period in which the operations of the PF motor 22 and the CR motor 13 overlap is obtained as the paper feed amount STpf until the paper feed is completed.

  In the acceleration time measurement process, when the activation command for the CR motor 13 is received, the acceleration time at the activation of the CR motor 13 is measured based on the output of the linear encoder 23 and the output of the speed calculation unit, and the measurement result is stored in the EEPROM 36. Remember. This acceleration time is the time from when the CR motor 13 is activated until it reaches the constant speed travel region, and is the time Tacc shown in FIG. The stored acceleration time Tacc is used for calculation when the CR motor 13 is next started. In the distance calculation process, the distance Lc between the current position of the stopped carriage 12 and the next print start position is calculated based on the output of the linear encoder 23 and the print information sent from the CPU 31.

In the movement time calculation process, a movement time Tcr required for the carriage 12 to move from the stop position to the print start position is calculated (see FIG. 4). This movement time Tcr is Tuv when the time from the arrival of the carriage 12 at the constant speed traveling region where the vehicle 12 travels at the constant speed Ve until the start of printing is Tuv, at the time of the previous activation of the CR motor 13 stored in the EEPROM 36. Using the acceleration time Tacc, it is expressed by the following equation.
Tcr = Tacc + Tuv (1)
When the weight of the carriage 12 changes abruptly before and after the power is turned on or the carriage 12 is cleaned, the acceleration time Tacc used in the above calculation is the minimum value of the assumed acceleration time.

On the other hand, the time Tuv used in the above calculation is the next print start position from the stop position (current position) of the carriage 12 obtained in the distance calculation process, where Lt is the distance that the carriage 12 travels during the acceleration time Tacc. It is shown by the following formula using the distance Lc until.
Tuv = (Lc−Lt) / Ve (2)
The distance Lt that the carriage 12 travels during the acceleration time Tacc is expressed by the following equation.
Lt = Ve · Tacc / 2 (3)
The speed Ve is a predetermined value determined in advance. The travel time Tcr is obtained from the above equations (1), (2), and (3). The acceleration time Tacc may be obtained by calculation from the speed data stored in the PROM 34 instead of being measured and acquired, or the calculation result stored in the EEPROM 36 or the like as data is read out and used. It is also possible to do it.

  In the paper feed amount calculation processing, based on the movement time Tcr calculated by the movement time calculation processing, the same time as the movement time Tcr until the PF motor 22 advances through the constant speed traveling area at a predetermined speed Vep and stops. When this is assumed, the paper feed amount STpf fed by the PF motor 22 during the time Tcr is calculated.

This paper feed amount STpf is obtained as follows. The deceleration time Tpd of the PF motor 22, that is, the time Tpd until the PF motor 22 stops from the predetermined speed Vep is a constant value determined according to the predetermined speed Vep. If the paper feed amount fed during the unit distance of the PF motor 22 (for example, during one rotation) is α, the paper feed amount STpf is given by the following equation.
STpf = α · (Vep · (Tcr−Tpd) + Vep · Tpd / 2) (4)
Upon receipt of the next print drive request from the sequence control unit 51, the CR motor driver 53 sends a CR start command request to the PF motor driver 52. The PF motor driver 52 that has received this CR start command request receives the overlay calculation unit 55A. The above calculation for determining the paper feed amount STpf is started. Further, the PF motor driver 52 acquires the actual paper feed amount Spf counted by the PF counter 56 from the motor control unit 44, and calculates the paper feed amount Spf from the current paper feed amount SApf (total paper feed amount) to the present time. Subtract the paper feed remaining amount SRpf. Then, the paper feed amount STpf calculated by the overlay calculation unit 55A is compared with the paper feed remaining amount SRpf, and when the paper feed remaining amount SRpf becomes equal to or less than the paper feed amount STpf, the activation of the CR motor 13 is instructed. The CR activation signal to be output is output to the CR motor driver 53. Further, when the monitoring unit 55B determines that the trailing end of the paper 18 has deviated from the override area OR toward the downstream side in the transport direction, the PF motor driver 52 prints to stop ejection (fire). A stop command is output to the head driver 54.

  Next, the operation of the printer 10 will be described with reference to FIGS. FIG. 7 is a flowchart showing platen printing prevention processing (timer interruption processing), and FIG. 8 is a transaction diagram showing printing processing operations during normal operation and platen printing prevention processing in the printer. In FIG. 8, in the time series direction from the top to the bottom, the first half (upper half) shows the normal operation, and the second half (lower half) shows the platen printing prevention process. First, the flow of processing during normal operation and during platen printing prevention processing will be described with reference to FIG.

  First, the normal operation will be described. The sequence control unit 51 executes each sequence of paper feed / paper feed / print / discharge according to a command included in the print data received from the host computer 38. In the sequence processing during printing, as shown in FIG. 8, the “paper feeding” and “printing” sequences are alternately repeated. In the paper feed sequence, when a paper feed request is received from the sequence control unit 51, the PF motor driver 52 activates the PF motor 22 to drive the paper feed amount SApf instructed by the request. When paper feeding is started, the PF motor 22 responds to the sequence control unit 51 that paper feeding is started.

  When the sequence control unit 51 receives a paper feed start response, the sequence control unit 51 proceeds to the next print sequence and sends a print drive request to the CR motor driver 53 and the head driver 54. The CR motor driver 53 that has received the print drive request sends a CR start command request for requesting a CR start signal to instruct the start timing of the CR motor 13 to the PF motor driver 52 for CR-PF overlay control. On the other hand, when the head driver 54 receives the print drive request, the head driver 54 advances the print process inside and waits until the carriage 12 is activated and reaches the print start position.

  The PF motor driver 52 executes the program shown in FIG. 7 with a timer interrupt during paper feed driving. During the interruption process, a paper feed speed control feedback calculation (PID control calculation in this example) is performed to obtain a command value, and the obtained command value is output to the motor control unit 44 at every interruption cycle to perform paper feed control. Do. When a CR activation command request is received from the CR motor driver 53, the overlay calculator 55A is activated as one process during the timer interrupt process, and calculates a paper feed amount STpf that determines the CR activation timing. Then, the actual paper feed remaining amount SRpf is obtained by subtracting the count value (= Spf) of the PF counter 56 from the current paper feed amount SApf, and when the paper feed remaining amount SRpf becomes equal to or less than the paper feed amount STpf, the CR motor driver 53 Output CR activation signal to. During the normal operation, the paper state managed by the monitoring unit 55B is the “paper present” state in which the paper detection sensor 26 detects the paper 18, and thus printing is permitted. When printing is permitted, no special instruction is given to the head driver 54 in particular.

  Upon receipt of the CR start signal, the CR motor driver 53 starts the CR motor 13 and moves the carriage 12 from the stop position to the stop position at the end of the current scan at a speed according to a predetermined speed profile defined by the speed data. . When the carriage 12 reaches the print start position during this movement process, the head driver 54 outputs a print command to the print control unit 45 and the print operation by the recording head 15 is started. When the printing operation is completed, the head driver 54 transmits a print completion message to the sequence control unit 51. The sequence control unit 51 that has received the end of printing shifts to the next paper feed sequence.

  Next, the operation during the platen printing prevention process will be described. Here, it is assumed that the paper 18 whose length in the paper conveyance direction is shorter than the setting is being fed. When the next paper feed is performed, the trailing edge of the paper 18 passes through the detection unit of the paper detection sensor 26 during the paper feeding, and the trailing edge of the paper 18 is overridden in the override region OR at the end of the paper feeding (see FIG. 2). ) Deviate downstream in the transport direction.

  When shifting to the paper feed sequence, paper feed drive is started in response to a paper feed request. In the next printing sequence, when the PF motor driver 52 receives a CR activation command request from the CR motor driver 53 in the same procedure as described above, the overlay calculation unit 55A and the monitoring unit 55B are activated. At this time, when the paper detection sensor 26 detects the trailing edge of the paper 18, the monitoring unit 55B shifts the paper state to the “override” state and starts a determination calculation for preventing platen printing. In the determination calculation, the paper feed remaining amount SRpf at the time of trailing edge detection is calculated, and it is determined whether or not the paper feed remaining amount SRpf is larger than the initial override amount SORint (SRpf> SORint). If it is determined that SRpf> SORint is satisfied, which indicates that the end of the paper 18 deviates from the override area OR toward the downstream side in the transport direction at the current paper feed end point, a print stop command is output to the head driver 54.

  Even during the platen printing prevention process, if the actual paper feed remaining amount SRpf is equal to or less than the paper feed amount STpf obtained by the overlay calculation unit 55A, a CR activation signal is output to the CR motor driver 53. Upon receiving the CR activation signal, the CR motor driver 53 activates the CR motor 13 and moves the carriage 12 to the stop position at the end of the current scan. Even if the carriage 12 reaches the print start position during this movement process, the head driver 54 has already stopped printing based on the print stop command received earlier. Is not output (forced printing ends). For this reason, only the carriage 12 moves (runs idle) without printing operation (ink droplet ejection). For this reason, printing is not performed in a state where the trailing edge of the sheet 18 deviates from the override area OR toward the downstream side in the transport direction, and as a result, printing on the platen 19 is avoided. When the forcible printing ends, the head driver 54 transmits a message indicating the end of printing to the sequence control unit 51. The sequence control unit 51 inquires of the PF motor driver 52 when receiving the end of printing, and when notified of the end of forced printing as a response, the sequence control unit 51 performs a print interruption process.

  Next, timer interrupt processing executed in the PF motor driver 52 will be described in detail according to the flowchart shown in FIG. When the CPU 31 executes the program shown in FIG. 7, the calculation unit 55 of the PF motor driver 52 is constructed. For this reason, each calculation of the overlay calculation unit 55A and the monitoring unit 55B is also performed in the process of the flowchart shown in FIG. That is, in the timer interrupt process, the overlay calculation process and the platen print prevention process are performed together.

  As processing of the PF motor driver 52, the CPU 31 executes the program shown in the flowchart in FIG. 7 by timer interrupt processing at predetermined intervals. Here, steps S1 and S2 correspond to the processing of the overlay calculation unit 55A, and steps S3 to S11 correspond to the processing of the monitoring unit 55B. Further, in steps S12 and S13, the actual paper feed remaining amount SRpf obtained by subtracting the count value (= Spf) of the PF counter 56 from the current paper feed amount SApf is the paper feed obtained by the overlay calculation unit 55A. This corresponds to a process of outputting a CR activation signal when the amount becomes less than STpf. Further, steps S14 and S15 correspond to a paper feed speed control (for example, PID control) process.

  First, in step S1, it is determined whether or not a CR activation command is requested. If there is a CR activation command request, the process proceeds to step S2, and if there is no CR activation command request, the process proceeds to step S3.

  In step S2, CR-PF overlay calculation (CR start timing calculation) is performed. That is, the overlay calculation unit 55A calculates the paper feed amount STpf using the equation (4). This calculation cannot be performed until the print data for the current pass has not been sent and the print start position has not been determined. For this reason, when a CR activation command request is received before the print start position is determined, the calculation is performed when the print start position is determined thereafter. This calculation is performed only once when a CR activation command request is received in each paper feed.

  In the processing of steps S3 to S11, when there is a management of three paper states of “paper present”, “override”, and “paper absent” (S3 to S9) and a CR activation command request (that is, the next printing is scheduled), If the rear end of 18 deviates from the override area OR toward the downstream side in the transport direction, a process of issuing a print stop command is performed (S10, S11). The processing contents of these steps S3 to S11 will be described later.

  In step S12, it is determined whether or not the CR activation timing has come. That is, the paper feed amount STpf previously calculated in step S2 and the remaining paper feed amount SRpf obtained by subtracting the count value (paper feed amount up to the current position) of the PF counter 56 from the current paper feed amount SApf. In comparison, it is determined that the CR start timing has been reached when the actual paper feed remaining amount SRpf is equal to or less than the paper feed amount STpf. If the CR activation timing has been reached, the process proceeds to step S13. If the CR activation timing has not been reached, the process proceeds to step S14.

  In step S13, a CR activation signal is output to the CR motor driver 53. As a result, the CR motor driver 53 that has received the CR activation signal commands activation of the CR motor 13, and the carriage 12 starts moving from the current position (stop position).

  In step S14, PID calculation (PID control calculation) for paper feed control is performed. That is, the CPU 31 obtains a target value for speed control corresponding to the current paper feed position, which is a count value of the PF counter 56, with reference to the paper feed speed table, and PID calculation for bringing the actually measured value closer to the target value. To calculate the current PF command value. In step S 15, the current PF command value is output to the PF motor drive circuit 41 via the motor control unit 44. When the PF command value obtained by this PID calculation is commanded every interrupt cycle time, the paper is fed at a speed according to a predetermined speed profile. A plurality of speed data are prepared according to the difference in the paper feed amount, and speed data is selected such that the maximum speed (constant speed) increases as the paper feed amount increases.

  Next, processing in steps S3 to S11 for performing paper state management and platen printing prevention processing will be described in detail. The paper state managed by the monitoring unit 55B changes in order as the paper feed proceeds. The monitoring unit 55B manages the paper state by storing data in a predetermined storage area of the EEPROM 36, for example. For example, “with paper” is managed as “00”, “override” as “01”, and “without paper” as “10”. First, if it is determined in step S3 that the paper state is “paper present”, it is next determined whether or not the paper detection sensor 26 has switched from “paper present” to “paper absent” (S4). That is, it is determined whether or not the trailing edge of the paper 18 is detected. Here, “no paper” indicates a detection state of the paper detection sensor 26 and is different from “paper no” in the paper state.

  When the paper detection sensor 26 switches from “paper present” to “paper absent”, it is determined whether or not the paper feed remaining amount SRpf is larger than the initial override amount SORint (SRpf> SORint) (S5). If SRpf> SORint is not established, the paper state is set to the “override” state (S6). On the other hand, if SRpf> SORint is established, the paper state is set to the “no paper” state (S7). For example, when the paper 18 whose length in the paper transport direction is shorter than the setting is fed and the paper is fed at a transport distance longer than the initial override amount SORint, the end of the paper 18 is downstream from the override region OR in the transport direction. May deviate. In such a case, the paper state is set to “no paper”.

  When the paper state is “no paper”, it is determined that the paper state is “no paper” when the next timer interrupt process is executed (S3), and if the CR activation command request has already been received (S10). YES, a print stop command is output to the head driver 54 (S11). As a result, the PF motor driver 52 performs a print stop process, and the print operation (ink droplet ejection) by the recording head 15 is not performed. In the present embodiment, the CPU 31 that performs the determination process in step S5 constitutes a determination unit. Further, the CPU 31 that executes the processes of steps S10 and S11 constitutes a control means.

  9 to 11 are graphs respectively showing the velocity waveforms of the PF motor 22 and the CR motor 13 during the platen printing prevention process. Since the timing at which the trailing edge detection timing of the paper detection sensor 26 is generated varies depending on the timing, it is not possible to specify which of the trailing edge detection timing and the CR activation signal output timing comes first. FIG. 9 shows an example in which the CR activation signal is output after the paper detection sensor 26 detects the trailing edge. FIG. 9A shows the case where the trailing edge of the paper is in the override area OR at the end of paper feeding. FIG. 9B shows the trailing edge of the paper from the override area OR downstream in the transport direction when the paper feeding is finished. It is an example in the case of deviating.

  In the platen printing prevention process, the determination calculation (S5 to S7, S10, S11) is started when the paper detection sensor 26 detects the trailing edge of the paper 18 during paper feeding (YES in S4). In the determination calculation, a calculation process is performed to determine whether the trailing edge of the sheet 18 is in the override area OR at the end of the sheet feeding or whether the sheet 18 deviates from the override area OR in the transport direction. For example, as shown in FIGS. 9A and 9B, when the CR activation signal is output after the paper detection sensor 26 detects the trailing edge, the determination calculation is performed when the trailing edge is detected. Therefore, it is possible to determine whether printing is possible at the timing before the CR activation signal is output.

  For example, as shown in FIG. 9A, in the case of “override” determination in which the trailing edge position Pend is within the override area OR at the end of paper feeding, the CR motor 13 is activated almost simultaneously with the output of the CR activation signal, and the carriage When the print start position is reached after 12 reaches the constant speed travel region, ink droplet ejection is started (fire start). On the other hand, as shown in FIG. 9B, when it is determined “no paper” that the trailing edge position Pend deviates from the override area OR at the end of paper feeding, a print stop command is output and the head driver 54 performs print stop processing. I do. For this reason, after that, although the CR motor 13 is started almost simultaneously with the output of the CR start signal, even when the carriage 12 reaches the print start position, the ink droplet ejection is not performed by stopping (fire prohibited). For this reason, the carriage 12 runs idle.

  Also, as shown in FIGS. 10A and 10B, when the CR activation signal is output before the paper detection sensor 26 detects the trailing edge, the determination operation is performed when the paper detection sensor 26 detects the trailing edge. Start at the time. This calculation start timing is the same as that in Patent Document 1 because it satisfies the conditions of CR activation signal output and rear end detection (that is, override counter ON). For example, as shown in FIG. 10A, in the case of “override” determination in which the trailing edge position Pend is within the override area OR at the time of paper feeding completion, the CR motor 13 is started almost simultaneously with the output of the CR start signal, and the carriage When 12 reaches the print start position, ink droplet ejection is started (fire start). On the other hand, as shown in FIG. 10B, in the case of “no paper” determination that the trailing edge position Pend deviates from the override area OR at the end of paper feeding, the CR motor 13 is started almost simultaneously with the output of the CR starting signal. However, even when the carriage 12 reaches the print start position, the ink droplet ejection is not performed by stopping (fire prohibited). For this reason, the carriage 12 runs idle.

  FIG. 11 shows an example in which the current paper feed is started in a state where the rear end is located in the override area OR after the paper rear end is detected by the paper detection sensor 26 during the previous paper feed. In FIG. 11, the override region OR is widely drawn on a scale enlarged in the transport direction as compared with the graphs of FIGS. 9 and 10.

  As shown in FIGS. 11A and 11B, when the CR start command request is received (S1), the rear end of the sheet 18 is in the “override state” (S3) in the override area OR. The determination calculation (S8 to S11) is started with the reception of the CR activation command request as a trigger. Since the CR activation command request is naturally received before the CR activation signal output timing, the determination calculation is performed at a timing before the CR activation signal output timing. However, only when the print start position cannot be determined because the print data of the current pass has not been sent when the CR start command request is received, the determination calculation is started with a slight delay when the CR start command request is received.

  In the determination calculation, calculation processing (S8 to S11) including determination processing for determining whether the trailing edge of the paper 18 is in the override area OR at the time when the paper feeding is finished or deviates from the override area OR to the downstream side in the transport direction. Done. That is, it is determined whether or not the paper feed remaining amount SRpf exceeds the override amount SOR (SRpf> SOR) (S8). Here, the override amount SOR is a count value of the override counter 57, that is, a value obtained by subtracting the paper feed amount after detection of the trailing edge from the initial override amount SORint. By this determination calculation, it is possible to determine whether printing is possible at the timing before the CR activation signal s is output.

  For example, as shown in FIG. 11A, when it is determined that “there is paper” when the trailing edge position Pend is within the override area OR at the end of paper feeding, the CR motor 13 is started almost simultaneously with the output of the CR starting signal, When the carriage 12 reaches the print start position, ink droplet ejection is started (fire start). On the other hand, as shown in FIG. 11B, when it is determined that there is no paper at which the trailing edge position Pend deviates from the override area OR at the end of paper feeding, the CR motor 13 is started almost simultaneously with the output of the CR starting signal. However, even when the carriage 12 reaches the print start position, the ink droplet ejection is not performed by stopping (fire prohibited). For this reason, the carriage 12 runs idle.

  In the conventional apparatus described in Patent Document 2, when the paper feed is started from a state in which the rear end is located in the override region, the override counter is turned on (that is, after detection of the rear end of the paper detection sensor 26) and the CR activation signal. Since the determination calculation for determining whether printing should not be permitted upon reception is performed, the method of this embodiment can be determined with a margin as compared with this.

  As described above, in the present embodiment, the CR activation signal is output and the carriage 12 is activated even when printing is stopped. However, a configuration in which the output of the CR activation signal is stopped may be employed. That is, if it is determined that printing is stopped before the CR activation signal is output, a printing cancellation command is output and the output of the CR activation signal is stopped. According to this method, since the CR activation signal is not output in FIG. 9B, in addition to avoiding printing on the platen 19, it is possible to avoid idle running of the carriage 12. Further, since the CR activation signal is not output in the next and subsequent paper feeds after the trailing edge detection shown in FIG. 11B, it is possible to avoid printing on the platen 19 and avoiding the idle running of the carriage 12. . In particular, in the conventional apparatus of Patent Document 2, since the CR activation signal reception is included in one of the conditions for determining the trigger for starting the determination operation, the determination operation is always started after the CR activation signal is received. For this reason, the determination result is always after the CR motor has already been started. For this reason, the carriage always runs idle even if a print disapproval command is issued and no print operation is performed. On the other hand, in the case of the present embodiment adopting the above-described configuration, the determination result may be output before the CR activation signal is output, so the frequency of the carriage 12 idling when a print stop command is issued can be reduced. .

  When a print stop command is output, the sequence control unit 51 proceeds to a paper feed sequence as an interruption process. For this reason, when a print stop command is output, the process immediately shifts to a paper feed process, and paper feed of the next page of paper 18 is started. In other words, in the printer 10 of the present embodiment, the carriage 12 moves to a predetermined position on the movement path to operate the lever to bring the clutch means into the connected state, and the power of the PF motor 22 is fed to the paper feed roller (not shown). Can be communicated to. As a result, when the trailing edge of the paper 18 deviates from the override area, a print stop command is output and the output of the CR start signal for the print operation is stopped. Instead, the carriage 12 is moved to a predetermined position. Output CR activation signal.

  For example, if the carriage 12 is configured to run idle, the carriage 12 moves to a predetermined position after the completion of printing for that printing, but the configuration of this example can avoid the carriage 12 running idle. According to this, the arrival of the carriage 12 at the predetermined position is advanced, and the feeding start timing of the next page can be advanced accordingly.

  In addition, since the printer 10 according to this embodiment performs printing during acceleration, including the configuration in which the CR activation signal is always output and the carriage 12 is idling, the following advantages can be obtained. That is, in a pass (one carriage movement) in which printing in the acceleration process (printing during acceleration) is performed, there is not much time for the carriage 12 to reach the printing start position after the CR motor 13 is started. . When such a printing during acceleration is performed by the conventional apparatus described in Patent Document 2, as a result of the determination calculation started almost simultaneously with the activation of the CR motor, the printing operation is stopped even if the printing non-permission is instructed. It may happen after the print start timing has already been reached. This becomes more conspicuous as the printing start timing of printing during acceleration is earlier because of the demand for higher speed. In this case, in order to reliably prevent platen printing, the carriage start time is delayed until a judgment calculation result is obtained, or the carriage is started only when the movement time to the print start position is sufficiently secured. Processing is required. On the other hand, according to the printer 10 of the present embodiment, when a determination result is output before the CR start signal is output, a print stop command (print disapproval command) can be output before the carriage 12 is started. It is possible to reduce the frequency of special processing that sometimes delays the start timing of the carriage 12.

As described above in detail, according to the present embodiment, the following effects can be obtained.
(1) A determination operation for determining whether or not the trailing edge of the paper 18 deviates from the override area OR to the downstream side in the transport direction after the paper feeding is finished is triggered by the detection of the trailing edge of the paper 18 by the paper detection sensor 26. Start. For this reason, when the paper detection sensor 26 detects the trailing edge before outputting the CR activation signal, it is possible to quickly grasp whether or not the printing operation should be stopped before the CR activation signal is output. Therefore, it is easy to avoid the inconvenience that printing is started due to a delay in the determination that printing should be stopped, thereby preventing platen printing more reliably than in the conventional apparatus.

  (2) Since the printer 10 is configured to perform printing during acceleration in which the printing operation starts during the acceleration of the carriage 12, the time from the start of the carriage to the start of the printing operation is very short. Even during scanning in which printing during acceleration is performed, since the frequency with which the determination result is obtained with a margin before the carriage is started increases, it is possible to more reliably prevent a situation in which platen printing is erroneously caused by a determination delay. In addition, when a waiting time is provided to wait for the start of the CR motor 13 until a determination result is obtained in order to reliably prevent platen printing when the trailing edge is detected, the waiting time can be shortened as much as possible so that the determination result can be understood early. Therefore, it is possible to suppress a decrease in throughput due to the waiting time.

  (3) Furthermore, the paper detection sensor 26 detects the trailing edge of the paper 18 before outputting the CR activation signal, and the output of the CR activation signal is stopped when the determination result is output before the CR activation signal output condition is satisfied. The configuration can also be adopted. When this configuration is adopted, by stopping the output of the CR activation signal, not only the printing operation but also the idle running of the carriage 12 can be eliminated. If the carriage 12 is not idle, the unnatural movement of the carriage 12 can be reduced even when there is no printing operation. In addition, the power consumption is saved and the longevity of the CR motor 13 is extended by the amount of unnecessary idle movement. It contributes to that.

  (4) In the case of the print stop determination, in the configuration in which the print stop command is output and the output of the CR start signal is stopped, a CR start signal for moving the carriage 12 to a predetermined position is output instead of the output stop of the CR start signal. The paper feeding is started immediately. Therefore, the clutch means interposed between the PF motor 22 and the paper feed roller is immediately connected, and the next paper feed can be started early.

  (5) In the next and subsequent paper feeds after the detection of the trailing edge of the paper, the determination calculation starts with the reception of the CR activation command request as a trigger, and the paper feed remaining amount SRpf at that time is compared with the override amount SOR. SRpf> It is determined whether or not SOR is established, and it is determined whether or not printing can be continued (second determination step). For this reason, it can be started immediately after receiving the CR activation designation request whether or not printing can be continued. That is, it is possible to always determine whether or not to stop printing before starting the movement of the carriage 12 (that is, the recording head 15).

  (6) Since the PF motor driver 52 that manages paper feed / paper feed / paper discharge performs CR-PF overlay calculation and platen printing prevention processing (including determination calculation), calculation and determination between the drivers 52 to 54 is performed. The number of times necessary to exchange data is reduced. For this reason, it is possible to output a necessary command (CR start signal / printing stop command) at an early stage. That is, since the PF motor driver 52 that manages data necessary for calculation and determination performs the calculation and determination, the number of data exchanges can be reduced, and necessary commands can be output early.

  (7) When the printing operation is stopped, in the configuration in which the carriage 12 (recording head 15) always runs idle, extra control for stopping the movement of the carriage 12 (recording head 15) that does not affect the platen printing is performed. do not need. Therefore, the control content of the platen printing prevention process can be simplified.

  (8) Even when the paper 18 in the paper conveyance direction is shorter than the set length and the paper detection sensor 26 detects the trailing edge during paper feeding, the paper feed remaining amount SRpf exceeds the initial override amount. Since the printing operation can be stopped, the carriage operation can be overlapped even during paper feeding. Therefore, it contributes to further throughput improvement.

In addition, embodiment is not limited above, You may change as follows.
(Modification 1) In the embodiment described above, the PF motor driver 52 performs the platen printing prevention process, but the CR motor driver 53 or the DC unit 33 may perform the printing process. That is, the execution subject of the platen printing prevention process is not particularly limited.

  (Modification 2) In the program shown in FIG. 7, when the “paper out” state is set as the paper state (S7, S9), the print stop command (S11) is issued at the next timer interrupt processing. A configuration in which a print stop command is issued within the same interrupt process can also be employed.

  (Modification 3) In the above embodiment, the clutch means is provided and the power of the PF motor 22 is transmitted to the paper feed roller. However, a configuration in which a dedicated paper feed motor for driving the paper feed roller is also provided. Good.

  (Modification 4) The calculation content for obtaining the paper feed amount STpf in the overlay process can be changed as appropriate. For example, when the carriage is configured to accelerate with a curved acceleration profile, data of acceleration time Tacc along the curved profile may be stored in advance in a memory, and read out and used for calculation. . In addition, when the data used for the calculation is not a measurement value, it is possible to employ a configuration in which the calculation is performed by adding correction considering the change in the carriage weight to the data using the ink remaining amount data managed by the printer 10.

  (Modification 5) Although the initial override amount is set as a value corresponding to the distance from the position of the paper detection sensor 26 to the most upstream nozzle position of the recording head 15, it is not limited to this. For example, a configuration in which platen printing is prevented by prohibiting ink droplet ejection from the nozzle corresponding to the portion of the nozzles of the recording head 15 where the paper 18 no longer exists can be employed. In this case, the initial override amount may be set to the distance from the position of the paper detection sensor 26 to the most downstream nozzle position of the recording head 15. The initial override amount is not limited to this type of fixed value (a constant value), and may be a variable value. For example, it can be a variable value determined according to printing conditions. For example, the initial override amount is set to a different value according to the difference between “marginless printing” and “marginal printing”. That is, since the limit positions that can be printed on the paper in the transport direction are different between “marginless printing” and “marginal printing”, the initial override amount reflecting the respective marginal positions is set. In other words, in the case of “printing with borders”, the initial override amount is set so that printing is not performed in the margin area set as the printing condition. Set the initial override amount to print.

  (Modification 6) In the above embodiment, the present invention is embodied in an ink jet printer as a recording apparatus, but the present invention is not limited to this. The present invention can also be embodied in a recording apparatus (liquid ejecting apparatus) that ejects a liquid other than ink (including a liquid material in which particles of a functional material are dispersed) and records it on a recording medium. For example, for manufacturing liquid chips and biochips for spraying liquid materials containing dispersed or dissolved materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, EL (electroluminescence) displays, and surface-emitting displays. It may be a liquid ejecting apparatus that ejects a biological organic material to be used, or a liquid ejecting apparatus that ejects a liquid as a sample that is used as a precision pipette. In this case, the recording medium is a medium that is a droplet ejection target such as a substrate according to the application. The present invention may be applied to any one of these recording apparatuses (liquid ejecting apparatuses).

Hereinafter, the technical idea grasped | ascertained from the said embodiment and each modification is described.
(1) In the recording method according to any one of claims 1 to 7, the recording unit is provided in a movable body that is movable in a direction crossing a conveyance direction of the recording medium, and the second driving source. The recording method is characterized in that the movement of the moving body is started by starting up.

  (2) The recording method according to any one of claims 1 to 7 and the technical idea (1), further comprising a calculation step of calculating a start timing of the second drive source. Recording method.

  (3) The control means includes a sequence control unit (51) that controls the conveyance and recording operations in sequence, and a first drive source control unit (52) that performs control according to a request from the sequence control unit. A second drive source control unit (53) and a recording control unit (54), and the second drive source control unit receives a request from the sequence control unit and activates the second drive source. To the first drive source control unit, and the first drive source control unit sends the second drive source before stopping the drive of the first drive source based on the request from the second drive source control unit. Performs a calculation to determine the startup timing to be started, and when the startup timing determined by the calculation is reached, outputs a startup command to the second drive source control unit, determines whether the printing can be continued, and can continue printing. Judge not The recording apparatus according to claim 8, wherein the commanding fact that the recording operation is stopped to the recording control unit when. According to this, since the first drive source control unit that manages conveyance performs the calculation and the determination, it is possible to reduce the number of times that information is exchanged between the control units, and it is possible to perform necessary commands early. Become.

1 is a schematic perspective view of a printer according to an embodiment. FIG. 3 is a schematic side view illustrating a recording head and a transport mechanism. (A) is a top view of a linear encoder, (b), (c) is an output signal diagram. The graph explaining the overlap calculation of PF motor and CR motor. FIG. 2 is a block diagram illustrating an electrical configuration of the printer. The block diagram which shows a platen printing prevention apparatus. The flowchart which shows a timer interruption process. The transaction figure explaining normal operation processing and platen printing prevention processing. (A) (b) The graph which shows the speed waveform of PF motor and CR motor. (A) (b) The graph which shows the speed waveform of PF motor and CR motor. (A) (b) The graph which shows the speed waveform of PF motor and CR motor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printer as a recording apparatus (liquid ejecting apparatus), 11 ... Guide shaft which comprises a moving means, 12 ... The carriage which comprises a moving means and a moving body, 13 ... CR motor (carriage motor) as a 2nd drive source ), 14... Timing belt constituting moving means, 15... Recording head as recording means, 19... Platen, 22 .. PF motor (paper feed motor) as first drive source, 23. , 25 ... paper discharge roller constituting the conveying means, 31 ... CPU constituting the judging means and control means, 32 ... ASIC, 33 ... DC unit, 34 ... PROM, 35 ... RAM, 36 ... EEPROM, 38 ... Host computer, 39 ... CR motor drive circuit, 40 ... Head drive circuit, 41 ... PF motor drive circuit, DESCRIPTION OF SYMBOLS 2 ... Encoder, 43 ... Timer IC, 44 ... Motor control part, 45 ... Print control part, 50 ... Control part, 51 ... Sequence control part, 52 ... PF motor driver, 53 ... CR motor driver, 54 ... Head driver, 56 ... PF counter, 57 ... Override counter, 58 ... CR counter, 59 ... Counter, OR ... Override area.

Claims (5)

A first drive source that is driven to convey the recording medium, a second drive source that is driven to move a recording unit that performs recording on the recording medium, and the first and second drive sources. In the recording method in the recording apparatus, the conveyance and the recording are controlled so as to be alternately performed, and the second driving source is started before the first driving source is stopped during the control,
A detection step of detecting a trailing edge of the recording medium by a detection means at a position upstream in the transport direction from the recording position of the recording means;
A determination step of determining whether or not recording can be continued at the position of the recording medium at the end of the current conveyance based on the remaining conveyance amount of the recording medium at the time of detection of the trailing edge when the detection means detects the trailing edge; ,
When it is determined in the determination step that recording cannot be continued, if the start timing of the second drive source has come before the time point of detection of the rear end, the recording means starts after the start of the second drive source. On the other hand, if the start timing of the second drive source comes after the detection time of the trailing edge, the recording stop processing by the recording means is performed before starting the second drive source, and thereafter And a control step of starting the second drive source when the start timing arrives . The recording method for a recording apparatus according to claim 1 , wherein the recording unit is configured to be able to start recording in the middle of acceleration in a moving process. Whether or not the recording can be continued in the determining step is determined by determining whether the trailing end of the recording medium is transported from the position at the time of detection to a limit position where recording by the recording unit can be performed. 3. The recording method according to claim 1, wherein the recording method is performed by comparing the remaining conveyance amount of the recording medium when the trailing edge is detected. After the completion of the conveyance when the detection means detects the trailing edge, after the recording performed in a state where the trailing edge is located in the override area from the position at the time of detection to the limit position, the override is performed. Whether or not recording can be continued at the position of the recording medium at the end of the current conveyance in the next and subsequent times, instead of the determination step, in the next and subsequent conveyances that start from the state where the trailing edge is located in the area. A second determination step for determining whether or not the rear end at the start of conveyance positioned in the override region is the limit when a request to move the recording means for recording is received in the second determination step. Whether the recording can be continued at the position of the recording medium at the end of the current conveyance by comparing the override amount corresponding to the conveyance distance conveyed to the position with the conveyance amount of the recording medium Recording method in the recording apparatus according to claim 3, characterized in that to determine. A first driving source that is a driving source of a conveying unit that conveys the recording medium; a second driving source that is a driving source of a moving unit that moves the recording unit that performs recording on the recording medium; the first driving source and the second driving source; A recording apparatus comprising: a control unit that controls the drive source so that the conveyance and the recording are alternately performed; and the control unit that activates the second drive source before stopping the driving of the first drive source in the control. ,
Detecting means for detecting the trailing edge of the recording medium at a position upstream in the transport direction from the recording position of the recording means;
When the trailing edge of the recording medium is detected by the detection means, it is determined whether or not recording can be continued at the position of the recording medium at the end of the current conveyance based on the remaining conveyance amount of the recording medium at the time of detection of the trailing edge. A judging means for judging,
When the determination means determines that recording cannot be continued, the control means performs recording stop processing by the recording means if the start timing of the second drive source has come before the detection time of the trailing edge. On the other hand, if the start timing of the second drive source comes after the detection time of the rear end, the recording stop process by the recording means is performed before the start of the second drive source, and then the start timing comes. And a second driving source activated when the recording device is activated .

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