JP2008055805A - Recording device and recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording device which can perform recording on a medium even at the time of a shorter actual feeding error length than a set length of the medium, and can avoid a disable due to the recording extended from the medium and to provide a recording method. <P>SOLUTION: When the end of the sheet is detected at the time of a sheet feeding operation (S2), counting of a sheet length counter starts (S3), and the sheet is conveyed to a printing starting position (S4). When the rear end of the sheet is detected on the way of conveying to the starting of the printing (S5), it is determined whether the sheet feeding counting value does not reach the sheet rear end detecting position (S6). If it does not reach the sheet rear end detecting position, "1" is set to a sheet feeding error flag (S7). At this sheet feeding error time, after the sheet is fed to the printing starting position, whether it is ready to print or not is determined (S9). If determined to be ready to print, after it is fed to the printing starting position, the printing action is performed (S10), while if not determined to be ready to print, a sheet discharging operation is performed (S13). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a recording apparatus and a recording method for conveying a medium and recording an image or the like on a medium being conveyed.

  2. Description of the Related Art Conventionally, some printers that are one type of recording apparatus include an automatic sheet feeder (hereinafter referred to as ASF (Auto Sheet Feeder)) (for example, Patent Document 1). The paper set in the ASF is fed by driving the ASF when printing is started, and is automatically cued to the print start position. This print start position is determined based on the print conditions such as the paper size set by the user operating the input device on the print condition setting screen displayed on the monitor of the host computer such as a personal computer (PC). The position is determined according to the paper size. When paper is fed, the cueing is performed based on the position at which the paper detection sensor disposed between the ASF paper feed roller and the paper feed roller on the paper transport path detects the leading edge of the paper. Met.

In recent years, printing apparatuses capable of borderless printing have also been provided (for example, Patent Document 2). In the case of borderless printing, a printing area wider than the paper is set so that printing is performed also on the peripheral edge of the paper, and ink is ejected (discharged) to an area that protrudes a predetermined amount outside the paper. . For this reason, a platen having a structure in which ink droplets ejected to an area protruding from the outside of the paper does not adhere to the paper support portion of the platen is used. The platen used in this type of printing device has a liquid waste part that is arranged with an ink absorbing material such as felt that absorbs the ejected ink, and a slightly raised surface from the upper surface of the liquid waste part to guide and support the lower surface of the paper. For example, it has a convex part made of plastic.
JP 2003-291436 A JP 2006-198806 A

  By the way, for example, when the user makes a mistake and sets a sheet (for example, A5 size) shorter in the transport direction than the set size (for example, A4 size), when the sheet is cued to the recording start position, the trailing edge of the sheet is recorded. In some cases, the nozzle has already passed through the nozzle of the head, but depending on the print start position, printing may be possible on the headed paper. However, conventionally, when the paper size is different, the configuration is such that printing is not performed, and therefore printing is not performed even when printing is possible. However, if printing is possible, a part of the image may be printed on the paper, and there is a demand for printing. Even when printing, if ink adheres to the platen (especially the convex part), there is a problem that the ink on the platen adheres to the following paper and the back side of the paper becomes dirty. It is necessary to apply.

  The present invention has been made in order to solve the above-described problems, and the object thereof is to allow recording on a medium even when the actual length of the medium is shorter than a set value, and to protrude from the medium. An object of the present invention is to provide a recording apparatus and a recording method capable of avoiding problems caused by recording.

  The present invention provides a recording apparatus comprising a conveying unit that conveys a medium, and a recording unit that records on the medium conveyed by the conveying unit, and a detecting unit that detects at least a rear end of the medium; Determining means for determining whether recording from the recording start position on the medium is possible when the detection means detects the trailing edge of the medium in the middle of conveyance to the recording start position by the recording means; When it is determined by the determination means that recording from the recording start position is possible, recording is performed on the medium from the recording start position. On the other hand, when recording from the recording start position is determined to be impossible, recording is performed on the medium. And a control means for controlling the recording means and the conveying means.

  According to this, when the trailing end of the medium is detected by the detecting unit while the medium is being transported to the recording start position by the recording unit, the determination unit determines whether recording from the recording start position to the medium is possible. To be judged. When it is determined that recording from the recording start position is possible, recording is performed on the medium from the recording start position. On the other hand, if it is determined that recording from the recording start position is impossible, recording is not performed on the medium. Therefore, for example, even when the actual medium is shorter than the set medium size, recording can be performed on the medium conveyed to the recording start position determined from the set medium size. In addition, since recording is not performed when recording cannot be performed on the medium, contamination of a member such as a platen caused by recording performed on a portion protruding outward from the medium can be avoided. In this case, since the member such as the platen is not contaminated with the ink or the like, there is no fear that the subsequent medium is stained with the ink or the like attached to the member such as the platen.

  In the recording apparatus of the present invention, a platen is further provided at a position opposed to the recording means across the medium conveyance path, and the control means controls the recording means so that the recording that protrudes outside the medium is It is preferable to record on the medium as long as it is not applied to the recording prohibited area of the platen. The recording prohibited area of the platen refers to a portion on the platen where the recorded ink or the like adheres to a subsequent medium and the medium is soiled when recording is performed on the area.

  According to this, the recording by the recording means is performed on the medium as long as it does not extend to the recording prohibited area of the platen even when it protrudes outside the medium. Therefore, it is possible to avoid the ink recorded on the platen from soiling the subsequent medium.

  In the recording apparatus of the present invention, the determination unit includes a first distance corresponding to a conveyance distance of the medium from the medium rear end detection position by the detection unit to a recording limit position on the medium rear end side by the recording unit, Preferably, the determination is made based on a second distance from the trailing edge detection position to the recording start position.

  According to this, based on the first distance (override length) and the second distance from the trailing edge detection position to the recording start position, the determination unit determines whether recording from the recording start position is possible. To be judged.

  In the recording apparatus according to the aspect of the invention, it is preferable that the control unit masks a portion of data recorded in the recording prohibited area of the platen among the recording data to be recorded by the recording unit.

  According to this, the data of the portion recorded in the recording prohibited area of the platen in the recording data is masked. Therefore, it is possible to perform complete recording (without pixel defects or the like) over a wider range of the medium while avoiding recording in the recording prohibited area of the platen.

  Furthermore, it is preferable that the recording apparatus of the present invention further includes a measurement unit that measures a measurement value corresponding to the amount of the medium transported by the transport unit from the position where the leading end of the medium is detected by the detection unit. The measurement value may be the carry amount itself or a value obtained by offsetting the carry amount by a predetermined value.

  According to this, the measuring means measures a measurement value corresponding to the amount of medium transported by the transporting means from the leading edge detection position of the medium by the detecting means. For example, the length in the conveyance direction of the medium (medium length) can be acquired from the measurement value of the measurement means when the trailing edge of the medium is detected by the detection means. In addition, when information on the set length of the medium can be acquired, it is possible to determine the double feed of the medium using the measurement value of the measuring unit and the set length information.

In the recording apparatus of the present invention, medium length acquisition means for acquiring the set length of the medium,
Based on the measured value of the measuring means when the trailing edge of the medium is detected by the detecting means and the set length, it is determined whether or not there is a feeding error in which a medium shorter than the set length is fed. It is preferable that the determination by the determination unit is performed when it is determined that the feeding error has occurred.

  According to this, based on the measured value of the measuring unit when the trailing end of the medium is detected by the detecting unit and the set length, it is determined whether there is a feeding error in which a medium shorter than the set length is fed. Determined. Only when it is determined that there is a feeding error, it is determined whether or not recording from the recording start position is possible. Therefore, even when the fed medium is shorter than the set length, recording can be performed on the medium.

  In the recording apparatus of the present invention, it is determined that the medium length acquisition unit that acquires the set length of the medium and the transport amount defined by the measurement value of the measurement unit is longer than the set length beyond the allowable range. In this case, it is preferable to further include a double feed determining means for determining a double feed error.

  According to this, the set length of the medium is acquired by the medium length acquisition means. When it is determined that the transport amount defined by the measurement value of the measuring unit is longer than the set length beyond the allowable range, it is determined as a double feed error. Therefore, it is possible to know the occurrence of double feeding in which subsequent media are partially overlapped.

  The present invention also relates to a recording method in a recording apparatus comprising a conveying means for conveying a medium and a recording means for recording on the medium conveyed by the conveying means, wherein at least the rear end of the medium is detected by a detecting means. A detection step for detecting, and whether or not recording from the recording start position to the medium is possible when the trailing end of the medium is detected by the detecting means in the middle of conveying the medium to the recording start position by the recording means And when determining that recording from the recording start position is possible, recording is performed on the medium from the recording start position, while when recording from the recording start position is determined to be impossible And a control step of not recording on the medium. According to this, the same effect as the invention of the above recording apparatus can be obtained.

Hereinafter, an embodiment in which the present invention is embodied in a printer will be described with reference to FIGS. FIG. 1 is a perspective view of a printer according to the present embodiment.
The printer 11 as a recording apparatus is, for example, an ink jet printer. The printer 11 is equipped with an automatic sheet feeder (hereinafter referred to as ASF 13) as a feeding means for feeding paper P as a medium on the back side of the main body 12. A paper guide 17 including a paper feed tray 14, a hopper 15, an edge guide 16 and a paper support 14a is attached to the ASF 13. The ASF 13 includes a paper feed drive mechanism that feeds the paper set in the paper guide 17 into the main body 12 one by one.

  A carriage 18 that reciprocates in the main scanning direction (X direction in FIG. 1) is provided in the main body 12, and a recording head 19 is provided below the carriage 18. In the process of moving the carriage 18 in the main scanning direction X, a printing operation for ejecting ink from the recording head 19 onto the paper P and a paper feeding operation for transporting the paper P in the sub-scanning direction Y by a predetermined transport amount are alternately repeated. As a result, printing on the paper P is performed. The printed paper P is discharged from a paper discharge port 12 </ b> A that opens at the lower front side of the main body 12. The carriage 18 and the recording head 19 constitute a recording unit.

  FIG. 2 is a schematic side view of the automatic paper feeder and the transport device. As shown in FIG. 2, a hopper 15 is supported on the upper surface side of the sheet feed tray 14 disposed obliquely on the back surface of the main body so as to be tiltable within a predetermined angle range about the shaft 15a at the upper end. Yes. The hopper 15 is urged in a direction away from the paper feed tray 14 (upper left direction in FIG. 2) by a compression spring 21 interposed between the paper feed tray 14.

  Near the lower end of the hopper 15, a cylindrical sheet feeding roller 22 is disposed so as to be rotatable about a rotation shaft 23. The hopper 15 is configured to be tiltable between a paper feed position shown in FIG. 2 and a retracted position (not shown) spaced from the paper feed roller 22.

  A guide portion 14b is provided on the upper surface of the downstream end (left side in FIG. 2) of the paper feed tray 14. A retard roller 24 is disposed at a position facing the paper feed roller 22 in the vicinity of the upper end of the guide portion 14b. The retard roller 24 is provided such that it can be driven and rotated with respect to the paper feed roller 22 in a state where a constant rotational load is applied by a torque limiting mechanism such as a torque limiter. The hopper 15 and the retard roller 24 are configured to move in conjunction with each other.

  At a position downstream of the ASF 13 in the paper conveyance direction, a carriage 18 on which the ink cartridge 26 is mounted is provided so as to be movable along the guide shaft 27 in the main scanning direction X (the direction perpendicular to the plane of FIG. 2). A platen 28 that defines the distance between the recording head 19 and the paper P is disposed below the recording head 19. On both sides of the platen 28 sandwiched in the sub-scanning direction (the left-right direction in the figure), a paper feed roller 29 and a paper discharge roller 30 are respectively disposed.

  The paper feed roller 29 includes a pair of a transport driving roller 29a and a transport driven roller 29b, and the paper discharge roller 30 includes a pair of a paper discharge drive roller 30a and a paper discharge driven roller 30b. In the present embodiment, the conveyance drive roller 29a and the paper discharge drive roller 30a are driven by a PF motor 58 (paper feed motor) (see FIG. 3), which is the same drive source, and cooperate with each other to feed the paper P.・ Discharge paper. The paper feed roller 22 is driven by the ASF motor 56 and cooperates with the paper feed roller 29 to feed and feed the paper P.

  Between the paper feed roller 22 and the paper feed roller 29, there is a lever 31 whose lower end extends to reach the paper transport path, and an optical sensor unit 32 whose detection target is the upper end of the lever 31. A paper detection sensor 33 is provided. In the state where the paper P1 is not on the lower end side of the lever 31, the paper detection sensor 33 returns to the original position indicated by the two-dot chain line in FIG. The sheet P1 is turned on when the lower end of the lever 31 is pushed and rotated as shown by a solid line in FIG. Specifically, the sensor unit 32 includes a light emitter and a light receiver, and the lever 31 that has blocked the light emitted from the light emitter is pushed by the paper P1 to rotate, and the light is received by the light receiver. In this configuration, the paper detection sensor 33 is turned on.

  As shown in FIG. 2, the retard roller 24 can move up and down between a paper feed position that contacts the outer peripheral surface of the paper feed roller 22 and a retreat position (not shown) that is separated from the outer peripheral surface of the paper feed roller 22. It is configured. At the time of printing shown in FIG. 2, the retard roller 24 moves upward and is disposed at a position where the paper can be nipped between the paper feed roller 22 and the hopper 15 tilts in the biasing direction of the compression spring 21 accordingly. The paper P stacked on the hopper 15 is pressed against the paper feed roller 22. The uppermost sheet P of the paper P urged by the paper feed roller 22 as the hopper 15 moves upward is sandwiched between the paper feed roller 22 and the retard roller 24 by the rotation of the paper feed roller 22. Paper is fed. In this paper feeding process, the paper P biased to the paper feeding roller 22 by the balance between the rotational resistance of the retard roller 24, the frictional resistance of the peripheral surface of the paper feeding roller 22, and the frictional resistance of the surface of the paper P is Of these, only the topmost sheet P1 is separated from other sheets and fed.

  The retard roller 24 and the hopper 15 return to the retracted position when there is no next page to be fed next when the cueing of the paper is finished. Therefore, while there is a next page of paper to be fed, the hopper 15 and the retard roller 24 are arranged at the paper feed position shown in FIG. As a result, the paper is continuously fed with a slight paper gap. Specifically, the hopper 15 and the retard roller 24 are held at the paper feed position, and the rotation of the paper feed roller 22 is temporarily stopped when the trailing edge of the preceding paper and the leading edge of the succeeding paper pass the nip point of the paper feeding roller 22. After waiting for the interval between the preceding sheet and the succeeding sheet to be secured, the rotation of the sheet feeding roller 22 is resumed and the feeding of the succeeding sheet is started. By this control, an interval that can be detected by the lever 31 of the paper detection sensor 33 is secured between the preceding paper P1 and the succeeding paper P2.

  The leading end of the fed paper P1 passes between the paper feed rollers 29 and is cued to the printing start position between the carriage 18 and the platen 28. A large number of nozzles (nozzle groups) for ejecting ink are opened on the lower surface of the recording head 19, and the position of the nozzle (referred to as the most upstream nozzle) in the transport direction in the nozzle group is the head reference position ( The position of “▼” in FIG.

  The cueing position (printing start position) is determined according to layout conditions such as margin (top margin) and borderless printing, and a conveyance distance corresponding to the cueing position is instructed when paper is fed. After the paper P1 is fed (after the cueing is finished), the printing operation of the recording head 19 and the paper feeding operation are alternately performed, and the printing proceeds.

  FIG. 4 is a plan view showing the platen, recording head, and paper. As shown in the figure, the platen 28 has a substantially rectangular plate shape that is long in one direction, and the longitudinal direction of the platen 28 is opposed to the recording head 19 across the paper conveyance path (the left-right direction in FIG. 4). It is arranged in a state that matches. The platen 28 includes a substantially square plate-shaped base material 28a, a liquid disposal part 28b in which a liquid absorbing material such as felt is accommodated in a recess 28d on the upper surface side of the base material 28a, and an island shape inside the liquid disposal part 28b. And a plurality of convex portions 28c having a substantially square shape in plan view. The convex portion 28c is formed integrally with the base material 28a so as to protrude from the bottom surface of the concave portion 28d, and is made of plastic which is the same material as the base material 28a. The plurality of convex portions 28c are positioned so as to protrude slightly above the upper surface of the liquid discarding portion 28b, and the paper P passing through the upper surface of the platen 28 is supported by the convex portions 28c. For this reason, the paper P does not come into contact with the liquid disposal unit 28b.

  When borderless printing is performed, as shown in FIG. 4, a print area AP wider than the paper P by a predetermined amount is set, and ink droplets are ejected from the nozzles 19a of the recording head 19 to the print area AP. Thus, printing is performed on the entire sheet without margins. At this time, the ink droplets that have been ejected from the outside of the paper impinge on the liquid discarding unit 28b, and therefore are absorbed and collected by the felt of the liquid discarding unit 28b. Further, the convex portion 28c is a convex portion at a portion of the printing area AP that protrudes outward in the width direction of the paper, regardless of the paper size of the paper that is assumed to be used in the printer 11 in the longitudinal direction of the platen 28. The position of the convex portion 28c on the platen 28 is set so that the 28c is not positioned. A discard hole (not shown) is formed in the print area AP at a position protruding outside the paper in the width direction, and ink droplets ejected outside the print area AP in the paper width direction are in the discard hole. It is configured to be discarded. However, since FIG. 4 is a schematic diagram, the number of the convex portions 28c, the width / interval of the convex portions 28c in the platen longitudinal direction, and the like are not accurate.

  Further, when the ejected ink droplets adhere to the convex portion 28c, the back surface is stained with the ink of the convex portion 28c when the paper of the next page (following) is conveyed onto the platen 28. It is set in a recording prohibited area where ejection is prohibited. For this reason, in the present embodiment, even when a paper having a paper length shorter than the set paper size is fed, if printing on the paper fed up to the cue position is possible, the paper is printed on the paper. Although it is configured to perform printing, ink droplets are not ejected to the convex portion 28c, which is a recording prohibited area. Here, a plurality of nozzles 19a of the recording head 19 are formed in the paper transport direction (vertical direction in FIG. 4) to form a nozzle row (nozzle group). Ink can be ejected.

Next, the electrical configuration of a printer including an automatic paper feeder will be described with reference to FIG.
As shown in FIG. 3, the printer 11 includes a control unit 40 that performs various controls. The control unit 40 includes an interface 41 that is communicably connected to a host computer 35 (PC). A CPU 43, an ASIC 44 (Application Specific IC), a ROM 45, a RAM 46, a nonvolatile memory 47, and the like are connected to the bus 42 connected to the interface 41. The ROM 45 stores various programs including a trailing edge printing control processing routine shown in the flowchart of FIG. The CPU 43 executes a program stored in the ROM 45 to perform paper feed control, paper feed control, print control, paper discharge control, and the like. Among these, the CPU 43 executes a program of the trailing edge print control processing routine at the time of paper feed processing, thereby judging paper feed error and whether or not printing on paper is possible when a paper feed error occurs, and it is judged that printing is possible. If so, a process for executing printing is performed. The ROM 45 stores various data including speed control data for controlling the speed of the ASF motor 56 and the PF motor 58.

  The host computer 35 is provided with a printer driver (not shown), and is a print setting screen displayed on the display device 35a based on a user input instruction. The user operates the input device 35b to set the paper size, paper type, Get various print parameters such as layout. When receiving a print execution instruction from the input device 35b, the printer driver performs predetermined processing to generate print data. Specifically, the printer driver sequentially performs known resolution conversion processing, color conversion processing, halftone processing, staring processing (microweave processing), and the like. Then, a command is attached to the header of the obtained print image data to generate print data. In addition to the command, this header includes printing parameters such as the paper size, and parameters of the target speed and transport distance (paper feed amount, etc.) at the time of paper transport indicating the contents to be specified by the command.

  The CPU 43 inputs print data from the printer driver of the host computer 35 through the interface 41 and the bus 42, and acquires the paper length Psize from the header in the print data first received from the host computer 35. Also, the CPU 43 interprets commands included in the header of the print data, for example, various commands such as paper feed / paper feed / discharge, and specific contents of the instructions are indicated by numerical values, for example, paper feed / paper feed.・ Acquire parameters such as paper transport distance when paper is ejected.

  The ASIC 44 receives print image data out of the print data from the CPU 43, performs image processing on the print image data, and the bits of a predetermined gradation value used for generating an ejection signal for ejecting ink droplets from the nozzles of the recording head 19. Convert to map data. The ASIC 44 sends the converted bitmap data to the head driver 48. The head driver 48 controls the recording head 19 based on the bitmap data to eject ink droplets from the nozzles.

  Further, motor drivers 49, 50, 51, 52 are connected to the CPU 43. The CPU 43 drives and controls the carriage motor 55, the ASF motor 56, the sub motor 57, and the PF motor 58 (paper feed motor) via the motor drivers 49 to 52. Further, the output shaft of the PF motor 58 is connected to the transport drive roller 29a and the paper discharge drive roller 30a via a train wheel (not shown) so as to be able to transmit power. The motor drivers 50 and 52, the ASF motor 56, the PF motor 58, the paper feed roller 22, the paper feed roller 29, the paper discharge roller 30, and the like constitute a conveying means.

  Here, the ASF motor 56 rotates the paper feed roller 22. The sub motor 57 is connected to the retard roller 24 and the hopper 15 so as to be able to transmit power, and is driven so that the retard roller 24 and the hopper 15 move between the retracted position and the paper feeding position in conjunction with each other.

  The ASF motor 56 and the PF motor 58 are each provided with a rotary encoder (hereinafter referred to as encoders 61 and 62) that detects the rotation of each output shaft. Each encoder 61, 62 generates and outputs a pulse signal having a period inversely proportional to the rotational speed of the corresponding motor. An on / off signal of the paper detection sensor 33 and pulse signals from the encoders 61 and 62 are input to the CPU 43, respectively.

  Further, the CPU 43 includes a paper length counter 65, an ASF counter 66, a PF counter 67 and an override counter 68. The paper length counter 65 is reset by the CPU 43 when the paper detection sensor 33 is turned on, and counts the pulse edges of the pulse signal input from the encoder 62 after the reset.

  When the paper trailing sensor passes through the lever 31 of the paper detection sensor 33 and the paper detection sensor 33 is switched from the on state in which the paper is detected to the off state in which the paper is not detected, the override counter 68 is connected to the paper detection sensor 33 and the head. An override length b corresponding to the distance between the reference positions H is set. The value of the set override length b is decremented with the conveyance of the sheet, and the CPU 43 recognizes that printing is possible until the override counter 68 becomes “0”.

  The ASF counter 66 counts the pulse edges of the pulse signal input from the encoder 61 that detects the rotation of the ASF motor 56. The ASF counter 66 is reset prior to the start of the driving of the ASF motor 56, and is a measure corresponding to the paper feed amount (conveyance distance) of paper fed by the paper feed roller 22 driven to rotate by the ASF motor 56. Count the numbers. The CPU 43 ascertains the paper transport position with the paper feed start position as the origin from the count value of the ASF counter 66, and refers to a speed control table (not shown) to determine the speed (or cycle) corresponding to the transport position. To control the speed of the ASF motor 56.

  The PF counter 67 counts the pulse edges of the pulse signal input from the encoder 62 that detects the rotation of the PF motor 58. The PF counter 67 is reset before the driving of the PF motor 58 is started, and counts a count value corresponding to the transport distance of the paper transported by the paper feed roller 29 that is rotationally driven by the PF motor 58. The CPU 43 ascertains the paper transport position with the paper feed start position as the origin from the count value of the PF counter 67, and refers to a speed control table (not shown) to determine the speed (or cycle) corresponding to the transport position. To control the speed of the PF motor 58.

  FIG. 5 is a schematic side view of the paper transport process for explaining the counting process of the paper length counter 65 and the override counter 68. FIG. FIG. 5A shows a state when the leading edge of the paper P <b> 1 is detected by the paper detection sensor 33. The paper length counter 65 is reset when the paper detection sensor 33 is turned on, and starts counting the pulse edges of the pulse signal input from the encoder 62 after the reset.

  FIG. 5B shows a state when the paper is cued to the print start position. When the count value of the paper length counter 65 reaches the value of the print start position designated by the paper feed command, the driving of the motors 56 and 58 is stopped and the paper P1 is cued. After the first printing is performed at this cueing position, the position when the count value of the sheet length counter 65 coincides with the head reference position H (the most upstream nozzle) is the origin “0”. It is updated to a value corresponding to the carry amount. That is, the value is updated to a value Nh obtained by subtracting a value corresponding to the distance Lsh shown in FIG. Therefore, the sheet length counter 65 counts a count value Nx corresponding to the distance from the leading end of the sheet P1 to the head reference position H.

  FIG. 5C shows a state where the trailing edge of the paper has passed through the lever 31 of the paper detection sensor 33 and the paper detection sensor 33 has been switched from on to off, thereby causing a paper out detection state. At this time, if the size of the paper set by the user on the paper guide 17 is the same as the set paper size set in the printer driver, the count value Nrs of the paper length counter 65 at this time is the paper length acquired from the print data. It should match the value obtained by subtracting the distance Lsh from Psize (Psize−Lsh). Therefore, when the difference between the count value Nrs and the value (Psize−Lsh) is taken and the value of Psize−Lsh−Nrs is equal to or larger than a predetermined allowable value α (for example, a value within a range of 1 to 5 mm), the setting paper A paper feed error is determined as a paper shorter than the size is set. However, in this embodiment, even when such a paper feed error occurs, when the paper is cued to the print start position determined from the set paper size, the rear end of the paper is, for example, the most downstream nozzle of the recording head 19. If it does not pass, recording on the paper is possible. In this case, recording on the paper is performed.

  Further, when the paper detection sensor 33 is switched from on to off as shown in FIG. 5C, the override length b is set in the override counter 68, and the set value is decremented with the subsequent paper conveyance. The When the count value of the override counter 68 becomes “0”, the CPU 43 recognizes that the sheet has been transported to a print limit position where printing is impossible. In the present embodiment, the paper transport operation is temporarily stopped both when the paper detection sensor 33 detects the leading edge of the paper P1 and when the paper detection sensor 33 detects the trailing edge of the paper P1. This is to make the value set in the counter coincide with the paper position with high accuracy.

  FIG. 6 is a schematic plan view of the paper. FIG. 6A shows a case where printing is not possible due to a paper feed error, and FIG. 6B shows a case where printing is possible due to a paper feed error. In FIG. 6, the upward direction indicated by the arrow in FIG. 6A is the paper discharge direction (conveyance direction). Further, this figure is a view of the recording head viewed from the viewpoint of moving together with the paper P, and is depicted such that the recording head 19 moves relative to the paper P. In FIG. 6, thick lines drawn in the recording head 19 (19A to 19E) indicate nozzle rows. Further, in FIG. 6, a solid line paper P indicates a sheet actually fed, and a sheet Ps indicated by a two-dot chain line indicates a sheet having a set sheet size acquired from the printer driver.

  Here, in FIGS. 6A and 6B, the print area AP indicated by the two-dot chain line is set corresponding to the paper size of the set paper Ps, and the distance “S” is the print area. This is the transport distance for transporting the paper until the recording head 19D is positioned at the AP print start position. This transport distance S is acquired as a parameter of the paper feed command from the header of the print data. The recording head 19A shown in FIG. 6 shows a state in which the leading end of the paper reaches the head reference position H (the most upstream nozzle) and is located at the origin where the transport amount is “0”. The conveyance amount from the origin of the paper P is counted by the paper length counter 65, and the CPU 43 can grasp the position of the paper P in the conveyance direction (sub-scanning direction Y) from the count value of the paper length counter 65.

  In FIG. 6, the recording head 19 </ b> B indicates the position when the trailing edge of the sheet is detected by the sheet detection sensor 33, and the transport distance to this position is “Nrs”. When the trailing edge of the sheet is detected by the sheet detection sensor 33, the sheet feeding operation is temporarily stopped, and the counter for managing the sheet position is switched from the sheet length counter 65 to the override counter 68. Then, the remaining transport distance a (= S−Nrs) to the printing start position is set.

  Further, at this time, by using the count value Nrs of the sheet length counter 65 and the set sheet length Psize, it is determined whether or not Psize−Lsh−Nrs ≧ α is satisfied. to decide. In the example of the paper feed error shown in FIGS. 6A and 6B, both satisfy the condition of Psize−Nrs−Lsh ≧ α.

  If it is further determined that there is a paper feed error, it is determined whether or not printing on the paper is possible when transported to the print start position. This determination is made by determining whether the condition “a−Lnzl <b” is satisfied using the remaining transport distance a, the override length b, and the nozzle length Lnzl. If this condition “a−Lnzl <b” is not satisfied, it is determined that printing is impossible (example in FIG. 6A), and if this condition “a−Lnzl <b” is satisfied, it is determined that printing is possible ( Example of FIG. 6B). Here, the override length b corresponds to the distance from the position of the recording head 19B to the position of the recording head 19C when the trailing edge of the paper reaches the head reference position H. Further, the nozzle length Lnzl is set so that the nozzle row can be printed completely up to the rear end of the paper, and the nozzle row Lnzl is positioned at the position of the recording head 19E shown in FIG. This corresponds to the length of the portion protruding from the rear edge of the paper. In the present embodiment, the nozzle length Lnzl is set to the entire length of the nozzle row. Note that FIG. 4 is a schematic diagram, and the recording head 19 actually prevents ink from hitting the convex portion 28c even at the position of the paper Pi indicated by the two-dot chain line in the figure in which the nozzle row protrudes from the rear end of the paper by the entire length. And the positional relationship between the convex portions 28c are set. Of course, the value of the nozzle length Lnzl can be set to a value at which the ink does not strike the convex portion 28c according to the positional relationship between the convex portion 28c and the recording head 19. For example, the nozzle length Lnzl can be set to a value shorter than the total length of the nozzle row or zero.

  Next, the trailing edge printing control processing routine executed by the CPU 43 will be described with reference to FIG. The CPU 43 acquires data of the set paper length Psize, a paper feed command, and a transport distance S (parameter) necessary for transporting the paper to the print start position from the print data first received from the host computer 35. . The CPU 43 that executes a process of acquiring the set paper length Psize from the received print data constitutes a medium length acquisition unit.

First, in step S1, a paper feeding operation is started.
In step S2, it is determined whether the leading edge of the sheet has been detected. That is, as shown in FIG. 5A, when the paper detection sensor 33 detects the leading edge of the paper, the process proceeds to step S3, and when the leading edge of the paper is not detected, the paper feeding operation is continued until it is detected.

In step S3, the paper length counter 65 starts counting. That is, the paper length counter 65 is reset and counting starts from zero.
In step S4, the paper is conveyed to the print start position. That is, the sheet transport operation is performed until the count value of the sheet length counter 65 reaches a value corresponding to the print start position.

  In the next step S5, it is determined whether or not the trailing edge of the sheet has been detected. For example, as shown in FIG. 6, when the actual length of the fed paper P is shorter than the set paper length Psize, depending on the print start position, the trailing edge of the paper is moved during the paper feeding operation. The chance of being detected by the paper detection sensor 33 is increased. If the trailing edge of the sheet is detected, the process proceeds to step S6. If the trailing edge of the sheet is not detected, the process proceeds to step S8.

  In step S6, it is determined whether or not the count value Nx of the sheet length counter 65 has reached a value corresponding to the set sheet length. The CPU 43 acquires the set paper length Psize from the print data header. The set sheet length Psize is given as a counter count value conversion value. If the sheet length is correct and the same as the set sheet length by subtracting “Lsh” from the set sheet length Psize, the sheet length counter 65 is detected when the trailing edge is detected. A count value (= Psize−Lsh) to be taken is obtained (see FIG. 7A). This value (Psize−Lsh) corresponds to a value corresponding to the setting paper. In this embodiment, the determination value J (= Psize−Lsh−Nrs) obtained by subtracting the count value Nx (= Nrs) at the time of detecting the trailing edge of the sheet length counter 65 from the value (Psize−Lsh) is a predetermined allowable value. If the value is equal to or greater than α (for example, a predetermined value in the range of 1 to 5 mm) (J ≧ α), it is determined that a paper feed error has occurred when a paper having a paper length shorter than the set paper length Psize is fed. If the paper feed error satisfies J ≧ α, the process proceeds to step S7. If the paper feed succeeds without satisfying J ≧ α, the process proceeds to step S8. The CPU 43 that executes the process of step S6 constitutes a feeding determination unit.

  In step S7, “1” is set in the paper feed error flag. Here, the paper feed error flag is a flag for remembering the occurrence of a paper feed error when paper shorter than the set paper length Psize is fed. In the present embodiment, even if a paper feed error occurs, printing is performed on the paper as long as the ink protrudes from the paper and is discharged and the convex portion 28c of the platen 28 is not stained with ink. It is remembered by the paper feed error flag that this is not normal printing but special printing in which printing is performed on a paper having a shorter paper length than the setting.

  In step S8, it is determined whether or not the paper feed error flag is “1”. If the paper feed error flag is “1”, the process proceeds to step S9, and if it is not “1” (that is, “0”), the process proceeds to step S10.

  In step S9, it is determined whether printing is possible when the paper is cued to the print start position. If the process shifts from step S7 to the present process when the trailing edge of the sheet is detected, it is determined whether or not a−Lnzl ≧ b is satisfied. If a-Lnzl ≧ b is established and printing is possible, the process proceeds to step S10. If a-Lnzl ≧ b is not established and printing is impossible, the process proceeds to step S13. On the other hand, when the process is started from step S8 after cueing and printing is started, it is determined whether or not the count value Nb of the override counter 68 is equal to or larger than “−Lnzl”. If Nb ≧ −Lnzl is established and printing is possible, the process proceeds to step S10. If Nb <−Lnzl is not established and printing is impossible, the process proceeds to step S13. However, Lnzl is 0 <Lnzl ≦ nozzle row total length, and in this embodiment, Lnzl = nozzle row total length.

In step S10, a printing operation is performed.
In step S11, it is determined whether printing is completed. If printing is not completed, the process proceeds to step S12. If printing is completed, the process proceeds to step S13.

  In step S12, a paper feeding operation is performed. After the paper feeding operation, the process returns to step S5. That is, the process according to the determination result is executed among the processes in steps S5 to S10 and S12 until the printing is completed in step S11 or the printing is not possible in step S9.

In step S13, a paper discharge operation is performed.
For example, if the paper size is not wrong, the printing operation (S10) and the paper feeding operation (S12) are normally repeated alternately to advance printing on the paper. At this time, even if the trailing edge of the paper is detected by the paper detection sensor 33 during paper feeding or paper feeding, the paper feed error flag remains “0” because a−Lnzl ≧ b is not satisfied in step S6. Printing proceeds until printing is completed.

  On the other hand, if it is determined that a paper feed error has occurred when the trailing edge of the paper is detected (S6), and it is determined that printing is possible on the paper (a-Lnzl ≧ b is established) when cueing further (S7), then printing is performed. When the printing operation is finished after the head is cued (S10), the paper is fed (S12). Prior to the next printing operation, since the paper feed error flag is “1” (S8), it is determined whether Nb <−Lnzl is satisfied (S9), and if Nb <−Lnzl is satisfied. Since printing is possible, a printing operation is performed (S10). As the printing and paper feeding are alternately repeated in this way, the count value Nb of the override counter 68 is gradually decremented and it is determined that the printing is completed (YES in S11), or if Nb <−Lnzl is not established (S9). NO), the paper is discharged (S13).

  In the present embodiment, the CPU 43 also executes another program to determine the double feed error using the count value Nx of the paper length counter 65. FIG. 7 is a schematic plan view of a sheet for explaining determination of sheet double feed error. As shown in FIG. 7A, when the paper is correctly fed, the count value Nx of the paper length counter 65 is set to the most upstream nozzle (head reference position H) from the set paper length Psize notified from the printer driver. This is equal to a value (Psize−Lsh) obtained by subtracting a value Lsh corresponding to the distance between the paper detection sensors 33. Further, as shown in FIG. 7B, when the sheets are overlapped and fed, the count value Nx of the sheet length counter 65 becomes longer than the value (Psize−Lsh). Therefore, in this embodiment, the determination value K (= Nx−Psize + Lsh) obtained by subtracting the value (Psize−Lsh) from the count value Nx of the sheet length counter 65 is a predetermined allowable value β (a predetermined value within a range of 1 to 5 mm). ) It is determined whether or not the value is equal to or greater than the above value. If K ≧ β is satisfied, it is determined that a double feed error has occurred. It should be noted that the CPU 43 that executes this double feed determination program constitutes a double feed determination means.

  In the present embodiment, the CPU 43 configures the main control unit 71 by executing the main program, and the CPU 43 executes sequence control based on an instruction from the main control unit 71 by executing a subroutine by interrupt processing. Configure. FIG. 9 is a transaction diagram illustrating an instruction / response performed between the main control unit 71 and the sequence execution unit 72, processing performed by the sequence execution unit 72, and the like. FIG. 9A shows a case where printing is impossible due to a paper feed error, and FIG. 9B shows a case where printing is possible even with a paper feed error. First, a case where printing cannot be performed due to a paper feed error will be described with reference to FIG.

  The main control unit 71 issues a paper feed instruction. At this time, a distance S to the print start position is given as a parameter. The sequence execution unit 72 that has received the paper feed instruction performs a paper feed operation. When the paper detection sensor 33 detects the trailing edge of the paper (no paper) during the paper feeding, the paper feeding is interrupted at the detected position. Then, the sequence execution unit 72 notifies the main control unit 71 that the paper feed has failed and the conveyance distance Nr s to the paper feed interruption position as a parameter.

  Next, the main control unit 71 instructs the sequence execution unit 72 to feed paper, and gives the remaining paper feed distance “S−Nrs” (= a) as a parameter. The sequence execution unit 72 that has received the paper feed instruction determines whether or not a−Lnzl ≧ b is satisfied. However, in this non-printable example, a−Lnzl ≧ b is not satisfied and the print disabled determination is performed. If it is determined that printing is not possible, the main control unit 71 is notified that paper discharge has been performed and the paper feed has failed.

  Next, a case where printing is possible even with a paper feed error will be described with reference to FIG. The main control unit 71 issues a paper feed instruction. At this time, a distance S to the print start position is given as a parameter. The sequence execution unit 72 that has received the paper feed instruction performs a paper feed operation. Similarly to the case of FIG. 9A, when the paper detection sensor 33 detects the trailing edge of the paper (no paper) during paper feeding, the paper feeding is interrupted, and the sequence execution unit 72 causes the main control unit 71 to Is notified of the failure of paper feed and the conveyance distance Nrs to the paper feed interruption position as a parameter.

  Next, the main control unit 71 instructs the sequence execution unit 72 to feed paper, and gives the remaining paper feed distance “S−Nrs” (= a) as a parameter. The sequence execution unit 72 that has received the paper feed instruction determines whether or not a−Lnzl ≧ b is satisfied, and in this printable example, a−Lnzl ≧ b is satisfied and a printable determination is performed. If it is determined that printing is possible, the sequence execution unit 72 feeds the instructed remaining paper feed distance “S−Nrs” (= a). Then, a message to the effect that paper feeding is complete is sent to the main control unit 71. Next, the main control unit 71 issues a print instruction, and the sequence execution unit 72 performs printing and notifies the completion of printing. The main control unit 71 continues to issue a paper feed instruction, and the sequence execution unit 72 performs paper feed and printing alternately thereafter. The sequence execution unit 72 performs a print enable determination (determination of whether or not Nb <−Lnzl is satisfied) prior to each paper feed. If the print enable determination is made, the paper feed / print is performed at that time, and printing is not possible. In the case of determination, the paper is discharged and a paper feed failure is notified.

As described above in detail, according to the present embodiment, the following effects can be obtained.
(1) The conveyance distance from the leading edge of the sheet is managed by the sheet length counter 65. Therefore, the paper length can be managed using the count value Nx of the paper length counter 65. That is, if the distance Lsh between the head reference position H and the paper detection sensor 33 is added to the count value Nx of the paper length counter 65, the paper conveyance distance (Nh + Lsh) after the leading edge of the paper is detected by the paper detection sensor 33. Can be obtained. Then, it is possible to determine whether or not the transport distance (Nh + Lsh) has reached the set paper length Psize.

  (2) Judgment value J (= Psize−Lsh−Nrs) obtained by subtracting the count value Nrs of the sheet length counter 65 from the value (Psize−Lsh) when the trailing edge of the sheet is detected by the sheet detection sensor 33. Is a value greater than or equal to a predetermined allowable value α (for example, a predetermined value in a range of 1 to 5 mm), and a paper feed error in which a paper having a paper length shorter than the set paper length Psize is set and fed judge. Therefore, it is possible to detect a paper feed error in which the fed paper is shorter than the set paper size.

  (3) When a paper feed error is detected, it is determined whether or not a−Lnzl> b is satisfied using the values of the override length b, the remaining transport distance a to the print start position, and the nozzle length Lnzl. By determining, it is determined whether or not printing is possible when a paper with a paper feed error is cued. If it is determined that printing is possible, printing is performed on a paper with a paper feed error. Therefore, even if the paper size to be set by the user is wrong or the paper size setting in the printer driver is wrong, even if the actual paper length is shorter than the set paper length, it is possible to use paper that is misfeeded. As long as printing is possible.

  (4) Since it is determined whether or not printing is possible based on the above condition a-Lnzl> b, there is no fear that the convex portion 28c of the platen 28 is stained with ink even when printing is performed at the cueing position. For this reason, it is possible to avoid that the paper on the next page (following) is stained with the ink adhering to the convex portion 28c.

  (5) Further, after the override counter 68 becomes zero, printing is completed until the value Lnzl is further counted, so even if printing is performed on the paper at the time of paper feeding error, the convex portion 28c of the platen 28 is filled with ink. It is possible to avoid smearing, and there is no worry of smearing the paper on the next page with the ink of the convex portion 28c.

  (6) Further, if the determination value K (= Nx−Psize + Lsh) obtained by subtracting the value Psize−Lsh from the count value Nx of the sheet length counter 65 is a value equal to or greater than the predetermined allowable value β, it is determined that a double feed error has occurred. Therefore, a double feed error in which the next page paper is fed with the current page paper can be detected, so that the user can be notified of the occurrence of the double feed error, for example, by turning on a warning lamp of the printer 11. For this reason, for example, the next page of paper can be reset, and the next page of paper can be properly cued and printed correctly.

  (7) When the paper is cued and the first printing is completed, and the first paper feed or paper discharge is performed, the count value of the paper length counter 65 is set to match the leading edge of the paper with the head reference position H. Thus, the distance from the leading edge of the paper to the head reference position H can be managed by the count value of the paper length counter 65. In addition, a method in which the count value of the paper length counter 65 is not updated is possible. In this case, however, conversion is necessary each time when a frequently used conveyance position is acquired. However, in this embodiment, since the update is performed after the first printing operation after cueing, such troublesome conversion processing can be eliminated. Therefore, it is possible to prevent a delay in processing performed by acquiring the transport position, and it is possible to realize a high-speed paper transport by preventing a delay in starting a paper transport process such as paper transport.

It should be noted that the present invention is not limited to the above embodiments, and the following forms can also be adopted.
(Modification 1) In the above-described embodiment, the count value of the sheet length counter 65 is obtained when the sheet is cued to the print start position, and the position when the leading end of the sheet coincides with the head reference position H is the origin. However, it is not limited to this method. For example, when the leading edge of the paper is detected by the paper detection sensor 33, a value “−Lsh” obtained by offsetting the value Lsh corresponding to the distance between the paper length counter 65 and the head reference position H to the paper length counter 65 to the negative side. By setting, it is also possible to employ a process for setting the count value when the paper reaches the print start position to Nh. Further, it is possible to adopt a method in which the paper feeding operation is temporarily stopped when the leading edge of the paper coincides with the head reference position H, and the count value of the paper length counter 65 is made zero at this time.

  (Modification 2) In the above-described embodiment, the paper feeding operation is temporarily stopped when the paper detection sensor 33 detects the trailing edge of the paper. However, it is also possible to adopt a configuration in which paper is fed all at once to the print start position without being temporarily stopped. . In this case, it is sufficient to determine the paper feed error and whether or not printing on the paper at the time of the paper feed error is possible at the time when the conveyance to the printing start position is completed. In this case, when the paper detection sensor 33 detects the trailing edge of the paper and finishes cueing the paper, if the value after the countdown of the override counter 68 is a positive value, it is determined that printing is possible, and zero Or, if it is a negative value, it is determined that printing is impossible.

  (Modification 3) In the above-described embodiment, the printing is performed with ink ejected with all nozzles of the recording head enabled based on the recording data corresponding to the set paper size. It may be determined whether or not it is hit by the portion 28c), and if it is hit by the recording prohibition area, a configuration may be adopted in which the recording data is masked so as to prohibit ejection from the nozzle. According to this configuration, a complete image with no missing dots can be printed in the printable area of the paper.

  (Modification 4) In the above embodiment, the recording data corresponding to the set paper size is used. However, after the paper feed error is determined, the actual paper size is recognized from the count value of the paper length counter 65 at that time. In addition, it is possible to employ a method of masking the recording data in the paper width direction in order to prevent ink ejection to an area where the actual paper width is excessively exceeded. In this case, it is possible to avoid the ink that protrudes from the outside in the width direction of the paper from adhering to the recording prohibited area (the convex portion 28c), and then a larger size paper to be fed is the ink of the convex portion 28c. It can avoid getting dirty.

  (Modification 5) In the above embodiment, the ASF motor 56 and the PF motor 58 are provided separately, and the paper feed roller 22 and the paper feed roller 29 are driven by different drive sources. One drive source may be used.

(Modification 6) Each of the motors 56 and 58 which are drive sources constituting the conveying means is not limited to a DC motor, and other electric motors can be used. For example, a stepping motor can be used.
(Modification 7) In the above embodiment, the trailing edge printing control processing is realized by software by causing the CPU 43 to execute a program. However, for example, it may be realized by hardware by a control circuit (custom IC or the like). It can also be realized by cooperation between hardware and software.

  (Modification 8) The present invention is not limited to the ink jet printer. You may apply to other serial printers, such as a dot impact type printer. Further, it can be applied to a page printer. In this case, the present invention is not limited to a laser printer, and can also be applied to a recording apparatus having a line head type recording head having nozzles over the entire maximum sheet width. It can also be applied to a duplex printing apparatus.

  (Modification 9) In the above embodiment, the recording apparatus is embodied as an ink jet printer. However, the present invention can also be applied to other liquid ejecting recording apparatuses that eject liquid other than ink as liquid. Here, “recording” is not limited to recording by printing, but includes, for example, recording in which a liquid material containing a material used for a circuit wiring pattern is ejected to draw a wiring pattern on a substrate as a medium. For example, a liquid ejecting apparatus (recording apparatus) that ejects a liquid material in which materials such as electrode materials and color materials used for manufacturing liquid crystal displays, EL (electroluminescence) displays, and surface-emitting displays are dispersed or dissolved. Also good.

Hereinafter, the technical idea grasped | ascertained from the said embodiment and each modification is described.
(1) The transport unit includes a feed unit (13, 56) and a medium feed unit (30, 58), and the detection unit is configured to connect the feed unit and the medium transport unit on a medium transport path. The recording apparatus according to claim 1, wherein the recording apparatus is located in between.

  (2) The recording unit includes a recording unit (19a) capable of recording over a predetermined length in the transport direction, and the determination unit subtracts a set value less than the predetermined length from the second distance. When the value is larger than the first distance beyond the allowable range, it is determined that recording is impossible, and when the subtracted value is not larger than the first distance beyond the allowable range, it is determined that recording is possible. The recording apparatus according to claim 3. Here, the recording unit corresponds to the nozzle row in the embodiment. According to this, when the value obtained by subtracting the set value equal to or smaller than the predetermined length from the second distance is larger than the first distance beyond the allowable range, it is determined that recording is impossible. On the other hand, if the subtracted value is not larger than the first distance beyond the allowable range, it is determined that recording is possible. Therefore, even if a part of the range over the predetermined length that can be recorded by the recording unit can be recorded on the medium, recording is performed on the medium by the part of the recording unit.

  (3) The control means controls the conveying means to discharge the medium when the judgment means judges that recording from the recording start position is impossible. The recording device according to any one of the above.

  (4) The measurement unit according to any one of claims 5 to 7, wherein the measurement unit measures a conveyance amount having a position at a point when the leading edge of the medium reaches a reference position of the recording unit as an origin. The recording device described.

  (5) The measuring means includes a counting means for counting the amount of transport of the medium from the position where the detecting means has detected the leading edge of the medium, and a count value of the counting means (65) as a reference position of the recording means. The recording apparatus according to the technical idea (4), further comprising an update unit (43) for updating the transport amount from a position at which the leading end of the medium has reached to a value.

  (6) A platen is further provided at a position facing the recording unit across the medium conveyance path, and in the control step, when it is determined that recording from the recording start position is possible, the recording protruding from the medium is 9. The recording method according to claim 8, wherein recording is performed on the medium as long as the recording is not performed on the recording prohibited area of the platen.

1 is a perspective view of a printer according to an embodiment. FIG. 3 is a schematic side view showing an automatic paper feeder and a carriage. FIG. 2 is a block diagram illustrating an electrical configuration of the printer. FIG. 3 is a schematic plan view showing a sheet and a platen. (A)-(c) The schematic side view explaining sheet feeding processing. (A), (b) The schematic top view explaining the process at the time of a paper feeding error. (A), (b) The schematic plan view of the paper explaining double feed determination. 6 is a flowchart illustrating a paper feed process. (A), (b) The transaction figure explaining the processing at the time of paper feed error.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Printer as recording apparatus, 13 ... Conveying means and automatic paper feeder (ASF) as feeding means, 18 ... Carriage constituting recording means, 19 ... Recording head constituting recording means, 22 ... Paper feeding roller, 24 ... retard roller, 28 ... platen, 28b ... liquid discarding part, 28c ... convex part as recording prohibition area, 29 ... paper feed roller constituting conveying means, 30 ... paper discharge roller, 33 ... detection means As a paper detection sensor, 35... Host computer, 40... Control unit, 43... Control means, determination means, feed determination means, double feed determination means, CPU constituting medium length acquisition means, 45. 48 ... Head driver, 50, 52 ... Motor driver constituting control means, 51 ... Motor driver, 56 ... ASF motor, 57 ... Sub motor, 58 ... F motor, 61, 62 ... encoder, 65 ... paper length counter constituting measuring means, 66 ... ASF counter, 67 ... PF counter, 68 ... override counter, 71 ... main control unit, 72 ... sequence execution unit, P, P1 ... paper as medium, Nx ... count value as measurement value, H ... head reference position, a ... remaining transport distance (paper feed distance) as second distance, b ... override length as first distance, Lsh ... Distance between head reference position and paper detection sensor, Lnzl: Nozzle length.

Claims (8)

In a recording apparatus comprising a conveying means for conveying a medium, and a recording means for recording on the medium conveyed by the conveying means,
Detection means for detecting at least the trailing edge of the medium;
Judgment whether or not recording from the recording start position to the medium is possible when the trailing end of the medium is detected by the detecting means while the medium is being transported to the recording start position by the recording means Means,
When it is determined by the determination means that recording from the recording start position is possible, recording is performed on the medium from the recording start position. On the other hand, when recording from the recording start position is determined to be impossible, the medium is recorded. A recording apparatus comprising: control means for controlling the recording means and the conveying means so as not to perform recording. A platen is further provided at a position facing the recording means across the medium conveyance path,
2. The recording according to claim 1, wherein the control unit controls the recording unit to perform recording on the medium in a range in which recording that protrudes outside the medium is not applied to a recording prohibited area of the platen. apparatus.   The determination means includes a first distance corresponding to a conveyance distance of the medium from a medium trailing edge detection position by the detection means to a recording limit position on the medium trailing edge side by the recording means, and the recording from the trailing edge detection position. The recording apparatus according to claim 2, wherein the determination is performed based on a second distance to the start position.   4. The recording apparatus according to claim 2, wherein the control unit masks a portion of data recorded in a recording prohibited area of the platen from the recording data to be recorded by the recording unit. 5. .   5. The apparatus according to claim 1, further comprising a measurement unit that measures a measurement value corresponding to a conveyance amount of the medium by the conveyance unit from a position where the leading end of the medium is detected by the detection unit. A recording apparatus according to claim 1. Medium length acquisition means for acquiring a set length of the medium;
Based on the measured value of the measuring means when the trailing edge of the medium is detected by the detecting means and the set length, it is determined whether or not there is a feeding error in which a medium shorter than the set length is fed. The recording apparatus according to claim 5, further comprising: a feeding determination unit configured to perform the determination by the determination unit when the feeding error is determined. Medium length acquisition means for acquiring a set length of the medium;
And a double feed determining unit that determines a double feed error when it is determined that the transport amount defined by the measurement value of the measuring unit is longer than an allowable range beyond the set length. The recording apparatus according to claim 5 or 6. A recording method in a recording apparatus comprising: a conveying unit that conveys a medium; and a recording unit that records on the medium conveyed by the conveying unit,
A detection step of detecting at least the rear end of the medium by a detection means;
A determination step of determining whether or not recording from the recording start position to the medium is possible when the trailing end of the medium is detected by the detection unit while the medium is being transported to the recording start position by the recording unit; ,
When it is determined that recording from the recording start position is possible, recording is performed on the medium from the recording start position. On the other hand, when it is determined that recording from the recording start position is impossible, control is not performed on the medium. And a recording method.

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