JP2004009686A - Printing device, program, and computer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve image quality by enhancing accuracy of transfer of an object to be printed since the transfer of the object influences the image quality. <P>SOLUTION: The printing device is provided with a transferring mechanism for the transfer of the object depending on an amount of target tranfer and does print the above object by intermittently transferring the object with the aid of the above transferring mechanism, whereas a compensatory amount for the above target transfer to be made intermittently is characterized by its decision based on information as to the transfer conducted through the above transferring mechanism prior to the transfer. A printing device of this kind is capable of enhancing the transfer accuracy of the object for improving the image quality. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printing apparatus and a printing method for printing on a printing medium such as paper. The present invention also relates to a program and a computer system for controlling such a printing device.
[0002]
[Background Art]
2. Related Art As a printing apparatus that prints an image on various types of printing media such as paper, cloth, and film, an inkjet printer that performs printing by intermittently discharging ink is known. In such an ink-jet printer, printing is performed by alternately repeating a process of moving and positioning a printing medium in a paper transport direction and a process of discharging ink while moving a nozzle in a scanning direction.
[0003]
[Problems to be solved by the invention]
In a printer that intermittently conveys a printing medium and performs printing during the intermittent conveyance, the conveyance of the printing medium affects the quality of image quality.
SUMMARY An advantage of some aspects of the invention is to improve the image quality by increasing the accuracy of transport of a printing medium.
[0004]
[Means for Solving the Problems]
A main invention for achieving the above object has a transport mechanism for transporting a printing medium according to a target transport amount, and intermittently transports the printing medium by the transport mechanism to form the printing medium. A printing apparatus that performs printing, wherein the correction amount for the target transport amount during intermittent transport is determined based on information about transport performed by the transport mechanism before performing the transport. And
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in the following order.
"Overview of Disclosure"
"Overview of Printing Equipment (Inkjet Printer)"
"Relationship between paper transport amount and image quality degradation (reference example)"
"Correction of conveyance amount of the present embodiment"
"Configuration of Computer System"
"Other embodiments"
[0006]
=== Disclosure Overview ===
At least the following matters will be made clear by the description in the present specification and the accompanying drawings.
[0007]
A printing apparatus comprising a transport mechanism for transporting a print medium according to a target transport amount, wherein the print mechanism prints the print medium by intermittently transporting the print medium by the transport mechanism. A printing apparatus characterized in that a correction amount for the target transport amount at the time of a proper transport is determined based on information on transport performed by the transport mechanism before the transport is performed. According to such a printing apparatus, the target transport amount can be corrected by reflecting the transport state and the correction state before transport.
[0008]
In the printing apparatus, it is preferable that the information includes information on a transport amount of the printing medium performed by the transport mechanism. According to such a printing apparatus, the target carry amount can be corrected based on the carry amount performed by the carrying mechanism before carrying.
[0009]
In the printing apparatus, it is preferable that the information on the transport amount includes information on an accumulated transport amount obtained by accumulating a transport amount of the printing medium performed by the transport mechanism. According to such a printing apparatus, the correction amount can be determined based on the accumulation of the transport amount performed by the transport mechanism before performing the transport. Thus, the correction amount can be determined by reflecting the transport state and the correction state before the transport.
[0010]
In the printing apparatus, the correction amount may be determined based on the cumulative transport amount before performing the transport and a transport amount obtained by further accumulating the target transport amount on the cumulative transport amount. desirable. According to such a printing apparatus, the correction amount at the time of conveyance can be determined based on the accumulated conveyance amount before and after the conveyance.
[0011]
In the printing apparatus, it is preferable that the correction amount is determined according to a quotient obtained by dividing the accumulated carry amount by a reference carry amount as a reference. According to such a printing apparatus, if the cumulative transport amount is divided by the reference transport amount, it is possible to obtain the cumulative correction amount based on the quotient, so that the correction amount at the time of transport can be determined. .
[0012]
In the printing apparatus, it is preferable that the information on the transport amount includes information on an excess transport amount transported by the transport mechanism exceeding a predetermined transport amount. According to such a printing apparatus, the correction amount can be determined based on the excess transport amount. Thus, the correction amount can be determined by reflecting the transport state and the correction state before the transport.
[0013]
In the printing apparatus, it is preferable that the correction amount is determined based on a value obtained by adding the excess carry amount to the target carry amount. According to such a printing apparatus, the correction amount can be determined by reflecting the transport state and the correction state before and after the transport.
[0014]
In the printing apparatus, it is preferable that the predetermined transport amount is an integral multiple of a reference transport amount as a reference. According to such a printing apparatus, the target transport amount is corrected each time the transport mechanism transports the printing medium beyond the reference transport amount.
[0015]
In the printing apparatus, it is preferable that the target carry amount is corrected each time the carry of the reference carry amount is performed. According to such a printing apparatus, the correction of the target transport amount is evenly distributed.
[0016]
In the printing apparatus, it is preferable that the information includes information on the number of intermittent conveyances performed by the conveyance mechanism. According to such a printing apparatus, the target transport amount can be corrected based on the number of transports performed by the transport mechanism before the transport.
[0017]
In the printing apparatus, it is preferable that a correction ratio with respect to the number of times of conveyance is set in advance, and the correction amount is determined based on the number of times of conveyance and the ratio of the correction. According to such a printing apparatus, since the correction can be performed every predetermined number of times of conveyance, the correction of the target conveyance amount is evenly distributed.
[0018]
In the printing apparatus, it is preferable that the reference transport amount is set based on information on the printing medium. According to such a printing apparatus, since the reference transport amount is set according to the printing medium, correction can be performed according to the printing medium.
[0019]
In the printing apparatus, it is preferable that the reference transport amount is set based on a ratio of correction to the transport amount performed by the transport mechanism. According to such a printing apparatus, since the reference carry amount is set according to the ratio of the correction to the carry amount, the correction can be performed based on the carry amount.
[0020]
In the printing apparatus, it is preferable that the reference transport amount is set based on a print mode. According to such a printing apparatus, since the reference transport amount is set according to the print mode, correction according to the print mode can be performed.
[0021]
The printing apparatus further includes a detector for detecting a transport amount of the printing medium transported by the transport mechanism, wherein the correction amount is a minimum transport amount detectable by the detector. Desirably, it is an integral multiple. According to such a printing apparatus, the target transport amount can be corrected according to the resolution of the detector.
[0022]
A printing apparatus comprising a transport mechanism for transporting a print medium according to a target transport amount, wherein the print mechanism prints the print medium by intermittently transporting the print medium by the transport mechanism. The correction amount for the target transport amount at the time of the proper transport is determined based on information about the transport performed by the transport mechanism before the transport is performed, and the information about the transport includes the information performed by the transport mechanism. The information on the transport amount of the printing medium is included, and the information on the transport amount includes information on an excess transport amount transported by the transport mechanism exceeding a predetermined transport amount, and the correction amount is the excess transport amount. Is determined based on a value obtained by adding an amount to the target carry amount, and the predetermined carry amount is an integral multiple of the reference carry amount serving as a reference. The transport amount is corrected and The reference transport amount is set based on information on the printing medium, a correction ratio to the transport amount performed by the transport mechanism, and a print mode, and detects the transport amount of the printing medium transported by the transport mechanism. A printing apparatus, wherein the correction amount is an integral multiple of a minimum transport amount detectable by the detector. According to such a printing apparatus, the target transport amount can be corrected by reflecting the transport state and the correction state before transport.
[0023]
A printing method, comprising: a transport mechanism for transporting a print medium according to a target transport amount, wherein the print mechanism prints the print medium by intermittently transporting the print medium by the transport mechanism. A printing method characterized in that a correction amount for the target transport amount at the time of a proper transport is determined based on information on transport performed by the transport mechanism before the transport. According to such a printing method, the target transport amount can be corrected by reflecting the transport state and the correction state before transport.
[0024]
A printing mechanism for transporting the printing medium in accordance with a target transport amount, and intermittently transporting the printing medium by the transport mechanism to print the printing medium; A program for realizing a function of determining a correction amount for the target transport amount at the time of the transport based on information on transport performed by the transport mechanism before the transport is performed. According to such a program, it is possible to control the printing apparatus so as to correct the target carry amount by reflecting the carry state and the correction state before carrying.
[0025]
A computer system comprising a computer main body and a transport mechanism for transporting a printing medium according to a target transport amount, wherein the transport mechanism intermittently transports the printing medium and prints the printing medium. A computer system, wherein the correction amount for the target transport amount during intermittent transport is determined based on information on transport performed by the transport mechanism before performing the transport. According to such a computer system, the printing apparatus can correct the target conveyance amount by reflecting the conveyance state and the correction state before the conveyance.
[0026]
=== Overview of Printing Equipment (Inkjet Printer) ===
<Configuration of inkjet printer>
With reference to FIGS. 1, 2, 3, and 4, an outline of the printing apparatus will be described using an ink jet printer as an example. FIG. 1 is an explanatory diagram of the overall configuration of the ink jet printer of the present embodiment. FIG. 2 is a schematic view of the vicinity of a carriage of the ink jet printer of the present embodiment. FIG. 3 is an explanatory diagram around the transport unit of the inkjet printer of the present embodiment. FIG. 4 is a perspective view of the vicinity of a transport unit of the inkjet printer according to the present embodiment.
[0027]
The ink jet printer according to the present embodiment includes a paper transport unit 10, an ink discharge unit 20, a cleaning unit 30, a carriage unit 40, a group of measuring instruments 50, and a control unit 60.
[0028]
The paper transport unit 10 feeds a printing medium, for example, paper, to a printable position, and performs a predetermined moving amount in a predetermined direction (a direction perpendicular to the paper surface in FIG. 1 (hereinafter, referred to as a paper transport direction)) during printing. It is for moving paper. That is, the paper transport unit 10 functions as a transport mechanism that transports the paper. The paper transport unit 10 includes a paper insertion slot 11A and a roll paper insertion slot 11B, a paper feed motor (not shown), a paper feed roller 13, a platen 14, a paper feed motor (hereinafter, referred to as a PF motor) 15, It has a paper feed motor driver (hereinafter, referred to as a PF motor driver) 16, a paper feed roller 17A, a paper discharge roller 17B, a free roller 18A, and a free roller 18B. However, in order for the paper transport unit 10 to function as a transport mechanism, not all of these components are necessarily required.
[0029]
The paper insertion slot 11A is where a paper to be printed is inserted. The paper feed motor (not shown) is a motor that transports the paper inserted into the paper insertion slot 11A into the printer, and is configured by a pulse motor. The paper feed roller 13 is a roller that automatically conveys the paper inserted into the paper insertion slot 11 into the printer, and is driven by the paper feed motor 12. The paper feed roller 13 has a substantially D-shaped cross-sectional shape. Since the peripheral length of the circumferential portion of the paper feed roller 13 is set longer than the transport distance to the PF motor 15, the printing medium can be transported to the PF motor 15 using this circumferential portion. The rotation driving force of the paper feed roller 13 and the frictional resistance of a separation pad (not shown) prevent a plurality of print media from being fed at once. The transport sequence of the printing medium will be described later in detail.
[0030]
The platen 14 supports the paper S being printed. The PF motor 15 is a motor that feeds, for example, a paper to be printed, for example, paper in the paper transport direction, and includes a DC motor. The PF motor driver 16 is for driving the PF motor 15. The paper feed roller 17A is a roller that feeds the paper S transported into the printer by the paper feed roller 13 to a printable area, and is driven by the PF motor 15. The free roller 18A is provided at a position facing the paper feed roller 17A, and presses the paper S toward the paper feed roller 17A by sandwiching the paper S between the paper feed roller 17A.
[0031]
The paper discharge roller 17B is a roller that discharges the paper S on which printing has been completed to the outside of the printer. The discharge roller 17B is driven by a PF motor 15 by a gear (not shown). The free roller 18B is provided at a position facing the paper discharge roller 17B, and presses the paper S toward the paper discharge roller 17B by sandwiching the paper S between the paper S and the paper discharge roller 17B.
[0032]
The ink discharge unit 20 is for discharging ink onto a printing medium, for example, paper. The ink ejection unit 20 has a head 21 and a head driver 22. The head 21 has a plurality of nozzles serving as ink discharge units, and discharges ink intermittently from each nozzle. The head driver 22 drives the head 21 and causes the head to intermittently eject ink.
[0033]
The cleaning unit 30 is for preventing the nozzles of the head 21 from being clogged. The cleaning unit 30 has a pump device 31 and a capping device 35. The pump device sucks ink from the nozzles to prevent clogging of the nozzles of the head 21, and includes a pump motor 32 and a pump motor driver 33. The pump motor 32 sucks ink from the nozzles of the head 21. The pump motor driver 33 drives the pump motor 32. The capping device 35 seals the nozzles of the head 21 when printing is not performed (during standby) in order to prevent the nozzles of the head 21 from being clogged.
[0034]
The carriage unit 40 is for moving the head 21 in a predetermined direction (in FIG. 1, a scanning direction). The carriage unit 40 includes a carriage 41, a carriage motor (hereinafter, referred to as a CR motor) 42, a carriage motor driver (hereinafter, referred to as a CR motor driver) 43, a pulley 44, a timing belt 45, and a guide rail 46. . The carriage 41 is movable in the scanning direction, and fixes the head 21 (therefore, the nozzles of the head 21 intermittently eject ink while moving along the scanning direction). The carriage 41 detachably holds an ink cartridge 48 containing ink. The CR motor 42 is a motor that moves the carriage in the scanning direction, and includes a DC motor. The CR motor driver 43 is for driving the CR motor 42. The pulley 44 is attached to a rotation shaft of the CR motor 42. The timing belt 45 is driven by the pulley 44. The guide rail 46 guides the carriage 41 in the scanning direction.
[0035]
The measuring instrument group 50 includes a linear encoder 51, a rotary encoder 52, a paper detection sensor 53, and a paper width sensor 54. The linear encoder 51 is for detecting the position of the carriage 41. The rotary encoder 52 is for detecting the rotation amount of the paper feed roller 17A. The configuration and the like of the encoder will be described later. The paper detection sensor 53 is for detecting the position of the leading edge of the paper to be printed. The paper detection sensor 53 is provided at a position where the position of the leading edge of the paper can be detected while the paper feed roller 13 is transporting the paper toward the paper feed roller 17A. The paper detection sensor 53 is a mechanical sensor that detects the leading edge of the paper by a mechanical mechanism. More specifically, the paper detection sensor 53 has a lever rotatable in the paper transport direction, and this lever is arranged to protrude into the paper transport path. Therefore, the leading end of the paper comes into contact with the lever, and the lever is rotated. The paper detection sensor 53 detects the position of the leading end of the paper by detecting the movement of the lever. The paper width sensor 54 is attached to the carriage 41. The paper width sensor 54 is an optical sensor having a light emitting unit 541 and a light receiving unit 543, and detects the presence or absence of paper at the position of the paper width sensor 54 by detecting light reflected by the paper. The paper width sensor 54 detects the position of the edge of the paper while being moved by the carriage 41, and detects the width of the paper. The paper width sensor 54 can detect the leading edge of the paper based on the position of the carriage 41. Since the paper width sensor 54 is an optical sensor, the accuracy of position detection is higher than that of the paper detection sensor 53.
[0036]
The control unit 60 controls the printer. The control unit 60 has a CPU 61, a timer 62, an interface unit 63, an ASIC 64, a memory 65, and a DC controller 66. The CPU 61 controls the entire printer, and gives control commands to the DC controller 66, the PF motor driver 16, the CR motor driver 43, the pump motor driver 32, and the head driver 22. The timer 62 periodically generates an interrupt signal for the CPU 61. The interface unit 63 transmits and receives data to and from a host computer 67 provided outside the printer. The ASIC 64 controls printing resolution, head driving waveforms, and the like based on print information sent from the host computer 67 via the interface unit 63. The memory 65 is for securing an area for storing programs of the ASIC 64 and the CPU 61, a work area, and the like, and has storage means such as a PROM, a RAM, and an EEPROM. The DC controller 66 controls the PF motor driver 16 and the CR motor driver 43 based on a control command sent from the CPU 61 and an output from the measuring instrument group 50.
[0037]
<About the configuration of the encoder>
FIG. 5 is an explanatory diagram of the linear encoder 51.
The linear encoder 51 is for detecting the position of the carriage 41, and has a linear scale 511 and a detection unit 512.
The linear scale 511 is provided with slits at predetermined intervals (for example, 1/180 inch (1 inch = 2.54 cm)), and is fixed to the printer body.
[0038]
The detection unit 512 is provided to face the linear scale 511, and is provided on the carriage 41 side. The detection unit 512 includes a light emitting diode 512A, a collimator lens 512B, and a detection processing unit 512C. The detection processing unit 512C includes a plurality (for example, four) of photodiodes 512D and a signal processing circuit 512E. , And two comparators 512Fa and 512Fb.
[0039]
The light-emitting diode 512A emits light when a voltage Vcc is applied thereto via resistors at both ends, and this light is incident on a collimator lens. The collimator lens 512B converts the light emitted from the light emitting diode 512A into parallel light and irradiates the linear scale 511 with parallel light. The parallel light that has passed through the slit provided on the linear scale passes through a fixed slit (not shown) and enters each photodiode 512D. The photodiode 512D converts incident light into an electric signal. The electric signals output from the respective photodiodes are compared in comparators 512Fa and 512Fb, and the comparison result is output as a pulse. Then, the pulses ENC-A and ENC-B output from the comparators 512Fa and 512Fb are output from the linear encoder 51.
[0040]
FIG. 6 is a timing chart showing waveforms of two types of output signals of the linear encoder 51. FIG. 6A is a timing chart of the waveform of the output signal when the CR motor 42 is rotating forward. FIG. 6B is a timing chart of the waveform of the output signal when the CR motor 42 is reversed.
[0041]
As shown in FIGS. 6A and 6B, the phase of the pulse ENC-A and the phase of the pulse ENC-B are shifted by 90 degrees regardless of whether the CR motor 42 is rotating forward or in reverse. When the CR motor 42 is rotating forward, that is, when the carriage 41 is moving in the main scanning direction, as shown in FIG. 6A, the phase of the pulse ENC-A is 90 degrees smaller than that of the pulse ENC-B. I'm advancing. On the other hand, when the CR motor 42 is inverted, as shown in FIG. 6B, the phase of the pulse ENC-A is delayed by 90 degrees from the phase of the pulse ENC-B. One cycle T of each pulse is equal to the time during which the carriage 41 moves through the slit interval of the linear scale 511 (for example, 1/180 inch (1 inch = 2.54 cm)).
[0042]
The detection of the position of the carriage 41 is performed as follows. First, a rising edge or a falling edge of the pulse ENC-A or ENC-B is detected, and the number of detected edges is counted. The position of the carriage 41 is calculated based on the counted number. When one edge is detected when the CR motor 42 is rotating forward, “+1” is added. When one edge is detected when the CR motor 42 is reversed, “−” is added. 1 ”is added. Since the period of the pulse ENC is equal to the slit interval of the linear scale 511, the amount of movement from the position of the carriage 41 when the count number is "0" can be obtained by multiplying the count number by the slit interval. That is, the resolution of the linear encoder 51 in this case is the slit interval of the linear scale 511. Further, the position of the carriage 41 may be detected using both the pulse ENC-A and the pulse ENC-B. Since the period of each of the pulse ENC-A and the pulse ENC-B is equal to the slit interval of the linear scale 511, and the phase of the pulse ENC-A is shifted by 90 degrees from the pulse ENC-B, the rising edge of each pulse When the number of detected edges is counted and the number of detected edges is counted, the count number “1” corresponds to １ ／ of the slit interval of the linear scale 511. Therefore, if the count number is multiplied by １ ／ of the slit interval, the movement amount can be obtained from the position of the carriage 41 when the count number is “0”. That is, the resolution of the linear encoder 51 in this case is １ ／ of the slit interval of the linear scale 511.
[0043]
The detection of the speed Vc of the carriage 41 is performed as follows. First, a rising edge or a falling edge of the pulse ENC-A or ENC-B is detected. On the other hand, the time interval between the edges of the pulse is counted by a timer counter. A period T (T = T1, T2,...) Is obtained from this count value. When the slit interval of the linear scale 511 is λ, the carriage speed can be sequentially obtained as λ / T. Further, the speed of the carriage 41 may be detected using both the pulse ENC-A and the pulse ENC-B. By detecting the rising edge and the falling edge of each pulse, the time interval between edges corresponding to １ ／ of the slit interval of the linear scale 511 is counted by a timer counter. A period T (T = T1, T2,...) Is obtained from this count value. Then, assuming that the slit interval of the linear scale 511 is λ, the carriage speed Vc can be sequentially obtained as Vc = λ / (4T).
[0044]
The rotary encoder 52 uses a rotary disk 521 that rotates in accordance with the rotation of the paper feed roller 17A instead of the linear scale 511 provided on the printer main body side. The other configuration is almost the same as that of the linear encoder 51 except that the detection unit 522 provided on the printer main body side is used instead of the 512 (see FIG. 4).
[0045]
Further, the minimum transport amount that can be transported by the transport unit is determined based on the resolution of the rotary encoder. In the present embodiment, the minimum transportable amount that can be corrected is 1/5760 inches (the interval between dots is 1/720 inch).
[0046]
<About the configuration of the nozzle>
FIG. 7 is an explanatory diagram showing the arrangement of nozzles on the lower surface of the head 21. On the lower surface of the head 21, a dark black ink nozzle group KD, a light black ink nozzle group KL, a dark cyan ink nozzle group CD, a light cyan ink nozzle group CL, a dark magenta ink nozzle group MD, and a light magenta nozzle A group ML and a yellow ink nozzle group YD are formed. Each nozzle group includes a plurality (n in the present embodiment) of nozzles serving as ejection ports for ejecting ink of each color. The first alphabet of the code indicating each nozzle group means the ink color, and the suffix “D” means that the ink has a relatively high density. “L” means that the ink has a relatively low density.
[0047]
The plurality of nozzles of each nozzle group are arranged at regular intervals (nozzle pitch: kD) along the paper transport direction. Here, D is the minimum dot pitch in the paper transport direction (that is, the interval of the dots formed on the paper S at the highest resolution). For example, if the resolution is 720 dpi, 1/720 inch (about 35. 3 μm). K is an integer of 1 or more.
[0048]
Further, the nozzles of each nozzle group are assigned lower numbers as the nozzles on the downstream side decrease (# 1 to #n). The nozzles of each nozzle group are provided so as to be located between the nozzles of the adjacent nozzle group with respect to the position in the paper transport direction. For example, the first nozzle # 1 of the light black ink nozzle group KL is provided between the first nozzle # 1 and the second nozzle # 2 of the dark black ink nozzle group KD with respect to the position in the paper transport direction. The paper width sensor 54 is provided at substantially the same position as the n-th nozzle #n located at the most downstream side with respect to the position in the paper transport direction. Each nozzle is provided with a piezo element (not shown) as a drive element for driving each nozzle to eject ink droplets.
[0049]
During printing, the paper S is intermittently conveyed by the paper conveyance unit 10 by a predetermined conveyance amount F, and during the intermittent conveyance, the carriage 41 moves in the scanning direction and ink droplets are ejected from each nozzle. You.
[0050]
=== Relationship between paper transport amount and image quality degradation (Reference Example) ===
<When there is no transport error>
FIG. 8 is an explanatory diagram showing a state of dot formation when there is no error when transporting the paper S (that is, when the transport amount of the paper S by the transport unit matches the target transport amount). . In the figure, for convenience of explanation, the head 21 has only seven nozzles for one color (that is, n = 7). Further, in FIG. 3, for convenience of explanation, the paper S is drawn as if it is also moving in the scanning direction. However, in actuality, the paper S only moves in the paper transport direction and is moved in the scanning direction. Does not move.
[0051]
In the figure, the nozzle pitch kD of this nozzle group is four times the dot pitch D (that is, k = 4). In the head 21, numerals 1 to 7 shown in circles indicate nozzle numbers. As shown in the drawing, the smaller the nozzle number is, the more downstream the nozzle is in the paper transport direction.
[0052]
The paper S is transported by the transport unit 10 in the paper scanning direction after the nozzles have been scanned once in the scanning direction (hereinafter, referred to as “pass”) by a transport unit F = LD (where L is an integer and D is the dot pitch). ) Just step. In the drawing, the transport amount F by the transport unit 10 is 7 · D (that is, L = 7), and the target transport amount is also 7 · D. When the paper S is transported with a constant transport amount F (= LD), an integer L such that a remainder obtained by dividing the integer L by the integer k is (k-1) may be employed. preferable.
[0053]
In the paper S, a circle indicates the position of a dot (pixel position) formed in the first pass, a square indicates a position of a dot formed in the second pass, and a hexagon indicates a third position. , And the octagon marks indicate the positions of the dots formed in the fourth pass. The number in each mark indicates the number of the nozzle that ejected the ink for forming the dot. Also, in the figure, two dots are formed for each pass, but actually, since the nozzles intermittently eject ink while moving in the scanning direction, a large number of dots are formed along the scanning direction. The dots are formed in a line (hereinafter, this is called a “raster line”).
[0054]
In the recording method shown in FIG. 3, each time the paper S is transported by the transport amount F in the scanning direction, each nozzle records a raster line immediately above the raster line recorded in the immediately preceding pass. The recording method shown in the figure is also an example of “interlace printing”. Here, “interlace printing” means a printing method in which k is 2 or more and raster lines that are not recorded are sandwiched between raster lines that are recorded in one pass.
[0055]
<When there is a transport error>
FIG. 9 is an explanatory diagram showing how dots are formed when there is an error when the paper S is transported (that is, when the transport amount by the transport unit includes an error with respect to the target transport amount). is there. FIG. 10 is an explanatory diagram showing how dots are formed when the target transport amount of the transport unit is corrected each time when there is an error in transporting the paper S. FIG. 11 is an explanatory diagram showing the appearance of print stripes (banding) in FIGS. 9 and 10.
[0056]
In FIG. 9, when the command signal of the target transport amount F (= LD) is input, the transport unit transports the paper by the transport amount (F + δ) including a certain plus error δ. That is, as compared with the case of FIG. 8, the paper S is further conveyed downstream by the error δ in the paper conveyance direction. As a result, the dot pitch between the raster lines (L2, L6) printed in pass 1 and the raster lines (L1, L5) printed in pass 2 is reduced by δ, and the raster line printed in pass 2 is reduced. And the dot pitch between the raster line (L4) printed in pass 3 becomes shorter by δ, and the dot pitch between the raster line printed in pass 3 and the raster line (L3) printed in pass 4 Becomes shorter by δ. As a result of the accumulation of the transport errors, as shown in FIG. 11A, for example, the raster line in the second column (L2: the line formed by the sixth nozzle in pass 1) and the raster line in the third column (L3: line formed by the first nozzle in pass 4), the dot pitch is widened by 3δ. For this reason, as shown in FIG. 11A, the dot pitch is larger than the ideal dot pitch D, so that light-colored stripes are generated with the naked eye. Such light stripes (hereinafter, referred to as “bright banding”, but also “white banding” or “light banding”) are observed as image quality deterioration.
[0057]
In FIG. 10, a command signal obtained by adding a correction amount −C to a target transport amount F (when the target transport amount is F, the transport amount of the transport unit is F + δ) is input to the transport unit. Here, C is the minimum transport amount that can be transported by the transport unit, and is a value determined by the resolution of the paper feed motor and the rotary encoder. In the case of the present embodiment, C = 1/5760 inches, depending on the resolution of the rotary encoder. However, here, since the transport error δ is smaller than the minimum correction amount C, if the transport amount F is corrected each time, an error δ−C in the direction opposite to that in FIG. 9 occurs. Therefore, in FIG. 10, compared with the case of FIG. 8, the paper S is further transported downstream by δ−C in the paper transport direction (that is, the paper S is insufficient by C−δ and Transported in the transport direction). As a result of the accumulation of the transport errors, as shown in FIG. 11B, for example, a raster line in the second column (L2: a line formed by the sixth nozzle in pass 1) and a raster line in the third column Dot line (L3: line formed by the first nozzle in pass 4) becomes narrower by 3D-3δ (spread by 3δ-3D). Therefore, as shown in FIG. 11A, since the dot pitch between L2 and L3 is narrower than the ideal dot pitch D, dark stripes occur with the naked eye. Such dark stripes (hereinafter referred to as “dark banding”, but also referred to as “black banding” or “dark banding”) are observed as image quality deterioration.
[0058]
<About the method of correcting the transport amount according to the present embodiment>
The above reference example shows that, even if the transport amount of the transport unit includes an error, if the transport amount of the transport unit is corrected every time, the image quality may be deteriorated. Therefore, it is necessary to appropriately set the correction of the transport amount of the transport unit instead of making it constant.
Hereinafter, the timing and how much the transport amount of the transport unit is corrected will be described in detail.
[0059]
=== Conveyance amount correction of this embodiment ===
<About the flow for performing the correction>
FIG. 12 is a flowchart showing the timing for correcting the carry amount in the present embodiment. In the present embodiment, the correction amount of the target transport amount F for transporting the paper S is determined based on the transport amount that has been already performed by the transport unit before the transport. The operation of the printer described below is controlled by the control unit 60 (or controlled by a printer driver).
[0060]
First, the state of “START” in the flowchart is a state in which the leading end of the paper S is detected by the paper width sensor 54 and is conveyed from that position to the printing start position. The excess carry amount Fc at this time is reset to zero (S101). The property of the excess transport amount Fc will be described later.
[0061]
Next, the carry amount F is added to the excess carry amount Fc (S102). Here, the carry amount F is an ideal one-time carry amount when the paper is carried intermittently. The carry amount F is determined by a print mode or the like, and is stored in a memory of the printer main body or set in advance by a printer driver.
[0062]
Next, the excess transport amount Fc is divided by the reference correction amount A to calculate a quotient m and a remainder a (S103). If the target transport amount is the reference transport amount A and the transport unit transports the paper based on the target transport amount, the paper includes a transport error of the minimum correction amount C with respect to the target transport amount A. Conveyed. Conversely, the value of the target transport amount at which the transport error becomes C becomes the reference transport amount A.
[0063]
If the calculated quotient m is smaller than 1 (S104), the target transport amount F is not corrected (S105), and the paper is transported based on the target transport amount F (S106). That is, the correction amount in this case is determined to be zero.
If the calculated quotient m is 1 or more (S104), the correction amount is determined to be m · C, the target carry amount F is corrected to Fm · C (S111), and the target carry amount F−m · C The paper is transported based on (S112). In this case, since the carry amount F of the paper has been corrected, the excess carry amount Fc is set to the remainder a calculated in S103 (S113).
[0064]
Next, the carriage is moved in the scanning direction, ink is ejected from the nozzles, dots are formed on the paper, and printing is performed (S121). If the printing is not completed, the process returns to step S102 (S122). By repeating this, the paper is conveyed intermittently. Then, during the intermittent conveyance of the paper, ink is ejected from the moving nozzles, and dots are formed on the paper to perform printing. It should be noted that the determination of the end of printing in step S122 can be made based on, for example, the accumulation of the paper transport amount.
[0065]
Even if the correction amount of the carry amount is determined based on the excess carry amount Fc as in the present embodiment, extreme proximity and separation of the dot pitch D can be suppressed, so that occurrence of banding can be suppressed. Therefore, if the excess carry amount Fc is stored in the memory, the correction amount for the target carry amount of the next carry can be calculated using the value.
[0066]
Further, according to the present embodiment, the target correction amount is corrected not only every time, but the target correction amount based on the excess transport amount with respect to a predetermined position. The target transport amount can be corrected reflecting the state. Further, according to the present embodiment, since the correction amount is determined by adding the target transport amount to the excess transport amount, the correction amount can be determined by reflecting the transport state and the correction state before and after transport. Therefore, according to the present embodiment, high-quality printing can be performed.
[0067]
In the flow of the method of correcting the carry amount according to the present embodiment, the target carry amount F is added to the excess carry amount Fc before carrying the paper, and the necessity and the correction amount of the target carry amount are determined based on the value. Since the determination is made, a transport error after the actual transport can be suppressed.
[0068]
<Dot formation>
FIG. 13 is an explanatory diagram showing how dots are formed in the present embodiment. FIG. 14 is an explanatory diagram illustrating a state in which the occurrence of print stripes (banding) is suppressed. Here, the target carry amount is set to F = 7 · D, and the reference carry amount is set to A = 14 · D. When the paper is transported by the target transport amount F, a transport error δ occurs. Then, every time the paper is transported by the transport amount of 14 · D, a transport error approximately equal to the minimum correction amount C occurs (that is, C = 2 · δ).
[0069]
The present embodiment is different from the above-described reference example in that there are both a case where the carry amount of the carry unit is corrected and a case where the carry amount of the carry unit is not corrected (in FIG. The conveyance amount is corrected at a rate of once for each conveyance.)
[0070]
Also in the present embodiment, when the command signal of the target transport amount F (= LD) is input, the transport unit transports the paper by the transport amount (F + δ) including a certain plus error δ. . The transport amount between pass 1 and pass 2 and the transport amount between pass 3 and pass 4 are not corrected. As a result, the dot pitch between the raster line (L2, L5) printed in pass 1 and the raster line (L1, L5) printed in pass 2 is reduced by δ, and the raster line printed in pass 3 is reduced. The dot pitch between the image and the raster line (L3) recorded in pass 4 is reduced by δ.
[0071]
On the other hand, in the present embodiment, the correction amount −C is added to the transport amount between pass 2 and pass 3. As a result, the dot pitch between the raster line printed in pass 2 and the raster line (L4) printed in pass 3 increases by C-δ (shortens by δ-C). Therefore, in the present embodiment, as shown in FIG. 14, for example, the raster line in the second column (L2: line formed by the sixth nozzle in pass 1) and the raster line in the third column (L3: pass 4, the dot pitch between the first nozzle and the line formed by the first nozzle is D + 3δ−C (= D + δ).
[0072]
In the present embodiment, as compared with the case of the above-described reference example, the accumulation of the transport error is reduced, so that it does not extremely approach or separate from the ideal dot pitch D. Light banding) can be suppressed.
[0073]
<Relationship between transport amount and correction amount>
FIG. 15 is a table showing the relationship between the transport amount and the correction amount in the case of FIG. Using this table and the flowchart of FIG. 12, the relationship between the transport amount and the correction amount will be described again. However, in FIG. 14 described above, the carry amount is corrected at a rate of once for every two transports, but in FIG. 15, for convenience of description, the carry amount is corrected at a rate of three times for every four transports. It shall be. That is, a 3C transport error occurs while the paper is transported by 7D × 4 (four transports), so that the reference transport amount A is A = 7D × 4/3.
[0074]
(Conveyance amount and correction amount for pass 1 and pass 2)
First, the amount of conveyance and the amount of correction up to pass 2 after the raster line of pass 1 is printed are calculated. The target carry amount F is added to the excess carry amount Fc that has been reset to zero, and Fc becomes 7 · D (S102). Next, the excess transport amount 7 · D is divided by the reference transport amount A (A = 7D × 4/3) to calculate a quotient and a remainder (S103). In this case, since the quotient is zero, the paper is transported based on the target transport amount F without correcting the target transport amount (S104 to S106). Thereafter, the carriage is moved in the scanning direction to eject ink from the nozzles, and the raster line of pass 2 is printed.
[0075]
(Conveyance amount and correction amount for pass 2 to pass 3)
Next, the transport amount up to the pass 3 and the correction amount are calculated. Since the carry amount has not been corrected in the previous carry, the excess carry amount Fc is 7 · D. The target carry amount F is added to the excess carry amount Fc, and Fc becomes 14 · D (S102). Next, the quotient and the remainder are calculated by dividing the excess carry amount of 14 · D by the reference carry amount A (A = 7D × 4/3) (S103). In this case, since the quotient is 1, the correction amount is determined to be 1 · C, the target carry amount F is corrected to FC, and the paper is carried based on the target carry amount FC. At this time, the remaining 4.67D is carried over.
[0076]
(Conveyance amount and correction amount for pass 3 and pass 4)
Next, the transport amount up to the pass 4 and the correction amount are calculated. Since the previous remainder 4.67D has been carried over, the target carry amount F is added to this excess carry amount Fc, and Fc becomes 11.67D (S102). Next, the excess transport amount 11.67D is divided by the reference transport amount A (A = 7D × 4/3) to calculate a quotient and a remainder (S103). In this case, since the quotient is 1, the correction amount is determined to be 1 · C, the target carry amount F is corrected to FC, and the paper is carried based on the target carry amount FC. At this time, the remaining 2.33D is carried over.
[0077]
(Conveyance amount and correction amount in pass 4 to pass 5)
Next, the transport amount up to the pass 4 and the correction amount are calculated. Since the previous remainder 2.33D has been carried over, the target carry amount F is added to this excess carry amount Fc, and Fc becomes 9.33D (S102). Next, the excess conveyance amount 9.33D is divided by the reference conveyance amount A (A = 7D × 4/3) to calculate a quotient and a remainder (S103). In this case, since the quotient is 1, the correction amount is determined to be 1 · C, the target carry amount F is corrected to FC, and the paper is carried based on the target carry amount FC. At this time, the remainder becomes zero.
[0078]
Note that the transport amount and the correction amount after the pass 5 are similarly obtained. In the case of the present embodiment, the transport amount is corrected at a rate of three times for four transports, so that a transport that performs correction and a transport that does not perform correction occur.
[0079]
<Relationship between correction amount and transport error>
FIG. 16 is a graph showing the relationship between the accumulated error δT and the number of times of conveyance (pass) when three corrections of the minimum correction amount C are performed for four conveyances. In the figure, the solid line indicates the cumulative error when the target transport amount is corrected, and the dotted line indicates the cumulative error when the target transport amount is not corrected. Note that the correction method of the present embodiment also corrects the target transport amount according to the flow of FIG.
[0080]
In the present embodiment, since the carry amount is corrected at a rate of 3 times for every 4 carry times, it is considered that a carry error of δ = 0.75C is generated for each carry. If the target transport amount is not corrected, the transport errors accumulate even if the transport error generated in one transport is smaller than the minimum correction amount C (see the dotted line in the figure). Then, as a result of accumulation of transport errors, banding occurs as described above.
[0081]
On the other hand, when the target carry amount is corrected at a rate of three times for four carrying times, the accumulation of carry errors is improved (see the solid line in the figure). Then, as a result of improving the accumulation of the transport error, the occurrence of banding can be suppressed.
[0082]
In particular, if the target transport amount is corrected according to the flow shown in FIG. 12, the accumulated error δT can be prevented from exceeding the minimum correction amount C. As a result, the dot pitch between raster lines can be made as close as possible to the ideal dot pitch with the resolution of the transport unit (the resolution of the encoder), so that the occurrence of banding can be suppressed.
[0083]
<Correction timing>
FIG. 17 is an explanatory diagram showing the timing of correction and the relationship between the correction amount and the reference transport amount A when the target transport amount F is corrected according to the flow of the present embodiment. In the figure, the continuation of the arrow indicates that the paper is being intermittently conveyed.
[0084]
In the present embodiment, the reference carry amount A is set such that the target carry amount is corrected at a rate of three times per four carrying times. That is, the reference carry amount A is set to F × 4/3.
[0085]
When the reference carry amount A is set in this way and the target carry amount is corrected in accordance with the flow shown in FIG. 12, the target carry amount is increased every time the paper is carried by a carry amount that is an integral multiple of the reference carry amount. The amount will be corrected. This means that when the transport unit transports the paper intermittently, the correction amount is almost equally distributed to each transport. Since the correction of the target transport amount is evenly distributed, the image quality is improved as compared with the case where the correction of the target transport amount is unevenly distributed.
[0086]
Note that, for example, the above-described excess carry amount Fc (= a) after the paper is carried to the pass 3 is a portion of the carry amount up to the pass 3 that exceeds the reference carry amount A among the carry amounts up to the pass 3. (2 × FA). Then, the excess transport amount Fc (= a) and the target transport amount F for the next transport are added, and a correction amount for the target transport amount for the next transport is calculated based on the value. Similarly, the correction amount of the target transport amount when the paper is transported from pass 4 to pass 5 is the transport amount (3F-2A) that exceeds 2 × A of the transport amount up to pass 4. It is calculated based on a value obtained by adding the target transport amount F.
[0087]
The correction amount for the target transport amount during the transport from pass 3 to pass 4 can also be obtained based on the cumulative transport amount. That is, if the accumulation of the transport amount up to pass 4 (the sum of the transport amount up to pass 3 and the target transport amount F) is divided by A, the cumulative correction amount at the time of transport up to pass 4 can be calculated (FIG. 17 for two minimum correction amounts C). On the other hand, if the accumulation of the transport amount up to the pass 3 is divided by A, the accumulation of the correction amount at the time of the transport up to the pass 3 can be calculated (one minimum correction amount C in FIG. 17). Then, from the accumulated difference between the two correction amounts, it is possible to determine the correction amount at the time of transport from pass 3 to pass 4. Therefore, if the accumulation of the transport amount is stored in the memory, the value may be used to calculate the correction amount for the target transport amount of the next transport. The determination of the correction amount based on the accumulation of the transport amount will be described later.
[0088]
<Setting of reference transport amount A>
As described above, the reference carry amount A is an element that determines the timing of correcting the carry amount. Since the reference transport amount A is set based on the transport error δ, mainly, (1) variation in the manufacture of the printer body, (2) the type of paper to be transported, (3) the transport amount of the paper, The reference transport amount A can be set based on the above.
[0089]
(1) A transport error due to a variation in the manufacture of the printer body occurs due to, for example, a variation in the diameter of the paper feed roller of the transport unit. This transport error is determined in the inspection of the printer at the factory when the printer is shipped from the factory. For example, at a factory, a test pattern (so-called patch pattern) is printed using a printer before shipping, and the transport error δ is determined based on the printing status of the test pattern. Note that, as such a test pattern, a pattern in which a plurality of patterns printed with different conveyance amounts are printed can be considered. Then, the transport error δ is determined by selecting the optimum pattern from the plurality of patterns. The reference transport amount A is set based on the determined transport error δ (that is, the reference transport amount A is set based on a variation in the manufacture of the printer body).
[0090]
(2) The transport error due to the type of paper to be transported occurs, for example, when the paper slips against the paper feed roller during transport. Accordingly, the transport error δ has a smaller value as the paper is more slippery, and has a larger value as the paper is less slippery. For example, plain paper has a larger transport error than glossy paper. Further, if the paper is roll paper, the paper tends to be pulled toward the roll side (that is, the direction opposite to the transport direction), so that the transport error δ becomes a small value (including the case where the transport error δ becomes negative). In this case, a table associating the transport error δ with the type of paper is stored in the memory of the printer main body or set in advance by the printer driver. Then, the transport error δ is determined based on the type of paper. The reference transport amount A is set based on the determined transport error δ (that is, since the reference transport amount A is set based on the type of paper, the target transport amount is corrected according to the type of paper. be able to.
[0091]
(3) The transport error due to the transport amount of the paper has a large value when the transport amount F is large, and has a small value when the transport amount F is small. In this case, a table associating the transport error δ with the target transport amount F is stored in the memory of the printer main body, or is set in advance by the printer driver. Then, the reference transport amount A is set based on the transport error stored in the table (that is, the reference transport amount A is set based on the paper transport amount).
[0092]
Since the paper transport amount is determined if the print mode is set, the reference transport amount A may be set based on the print mode. Thereby, the target transport amount can be corrected according to the print mode.
[0093]
=== Configuration of Computer System, etc. ===
Next, an embodiment of a computer system, a computer program, and a recording medium on which the computer program is recorded will be described with reference to the drawings.
[0094]
FIG. 18 is an explanatory diagram showing an external configuration of the computer system. The computer system 1000 includes a computer main body 1102, a display device 1104, a printer 1106, an input device 1108, and a reading device 1110. In the present embodiment, the computer main body 1102 is housed in a mini-tower type housing, but is not limited to this. The display device 1104 generally uses a cathode ray tube (CRT), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 1106, the printer described above is used. In the present embodiment, the input device 1108 uses the keyboard 1108A and the mouse 1108B, but is not limited thereto. In the present embodiment, the reading device 1110 uses the flexible disk drive device 1110A and the CD-ROM drive device 1110B, but is not limited thereto. For example, an MO (Magnet Optical) disk drive device or a DVD (Digital Versatile) is used. Disk).
[0095]
FIG. 19 is a block diagram showing a configuration of the computer system shown in FIG. An internal memory 1202 such as a RAM and an external memory such as a hard disk drive unit 1204 are further provided in a housing in which the computer main body 1102 is stored. A computer program for controlling the operation of the printer described above is recorded on a recording medium such as a flexible disk FD or a CD-ROM, and is read by the reading device 1110. Further, the computer program may be downloaded to the computer system 1000 via a communication line such as the Internet.
[0096]
FIG. 20 is an explanatory diagram illustrating a user interface of the printer driver displayed on the screen of the display device 1104 connected to the computer system. The user can use the input device 1108 to make various settings for the printer driver. For example, the user can select the type of paper to be printed from this screen. Then, the above-described reference transport amount A can be set according to the type of the selected paper. The user can select a print mode from this screen. When the print mode is determined, the transport amount of the paper is determined, so that the above-described reference transport amount A can be set. Further, the reference carry amount A may be set based on other information input by the user for setting the printer dry.
[0097]
FIG. 21 is an explanatory diagram of a format of print data supplied from the computer main body 1102 to the printer 1106. This print data is created from image information based on the settings of the printer driver. The print data has a print condition command group and a command group for each pass. The print condition command group includes a command indicating a print resolution, a command indicating a print direction (unidirectional / bidirectional), and the like. The print command group for each pass includes a target carry amount command CL and a pixel data command CP. If the above-described transport amount correction is performed on the computer main body side, the target transport amount command CL already includes the correction amount. If the correction of the transport amount is performed on the printer main body side, the target transport amount command CL does not include the correction amount. The pixel data command CP includes pixel data PD indicating a recording state of each pixel of a dot recorded in each pass. Although the various commands shown in FIG. 1 each have a header section and a data section, they are illustrated in a simplified manner. Further, these command groups are intermittently supplied from the computer main body side to the printer side for each command. However, the print data is not limited to this format.
[0098]
In the above description, an example in which the printer 1106 is connected to the computer main body 1102, the display device 1104, the input device 1108, and the reading device 1110 to form a computer system has been described. However, the present invention is not limited to this. Absent. For example, the computer system may include the computer main body 1102 and the printer 1106, and the computer system does not need to include any of the display device 1104, the input device 1108, and the reading device 1110. Further, for example, the printer 1106 may have some of the functions or mechanisms of the computer main body 1102, the display device 1104, the input device 1108, and the reading device 1110. As an example, the printer 1106 includes an image processing unit for performing image processing, a display unit for performing various displays, and a recording medium attaching / detaching unit for attaching / detaching a recording medium for recording image data captured by a digital camera or the like. It is good also as composition which has.
[0099]
In the above-described embodiment, a computer program for controlling the printer may be loaded into the memory 65 of the control unit 60. Then, the control unit 60 may execute the computer program to achieve the operation of the printer in the above-described embodiment.
[0100]
The computer system implemented in this way is a system superior to the conventional system as a whole.
[0101]
=== Other Embodiments ===
As described above, the printer and the like according to the present invention have been described based on one embodiment. However, the above embodiment is for facilitating the understanding of the present invention, and is for limiting and interpreting the present invention. is not. The present invention can be changed and improved without departing from the spirit thereof, and it goes without saying that the present invention includes its equivalents. In particular, even the embodiments described below are included in the printing apparatus according to the present invention.
[0102]
<Timing of correction 1>
In the above-described embodiment, the correction amount for the target carry amount is determined based on the information on the carry amount of the paper exceeding the predetermined carry area. However, the determination of the correction amount is not limited to the above-described embodiment, and may be based on another determining factor. In short, the determination of the correction amount may be based on the information on the transport amount already performed by the transport mechanism before the transport is performed.
[0103]
FIG. 22 is a flowchart showing the timing for correcting the carry amount according to another embodiment. In the present embodiment, the correction amount of the target transport amount F when the paper S is transported is determined based on the cumulative transport amount obtained by accumulating the transport amount already performed by the transport unit before the transport. The operation of the printer described below is controlled by the control unit 60 (or controlled by a printer driver).
[0104]
First, the state of “START” in the flowchart is a state in which the leading end of the paper S is detected by the paper width sensor 54 and is conveyed from that position to the printing start position. At this time, the accumulated carry amount Fa is reset to zero (S201). It should be noted that the accumulated carry amount Fa is a carry amount from the printing start position, as can be understood from the description below, and is a value obtained by accumulating the carry amounts already carried out by the carry unit.
[0105]
Next, the accumulated carry amount Fa is divided by the reference carry amount A to calculate a quotient m1. Further, a value obtained by accumulating (adding) the target carry amount F to the cumulative carry amount Fa is divided by the reference carry amount A to calculate a quotient m2 (S202). Here, the value obtained by adding the target transport amount F to the cumulative transport amount Fa is the cumulative transport amount after the paper S has been transported. The quotient m1 is related to the accumulation of the correction amount performed before the next conveyance. Further, the quotient m2 is related to the accumulation of the correction amount after the conveyance. Therefore, it is possible to determine the correction amount during the next transport based on the value obtained by subtracting the quotient m1 from the quotient m2.
[0106]
Next, the correction amount is determined as (m2−m1) · C, the target transport amount is corrected to F− (m2−m1) · C (S203), and the paper S is stored based on the corrected target transport amount. It is transported (S204). That is, the correction amount is determined based on the cumulative transport amount before performing the transport and the cumulative transport amount after performing the transport. After the conveyance, the value of the accumulated conveyance amount is set to Fa + F (S205).
[0107]
Next, the carriage is moved in the scanning direction, ink is ejected from the nozzles, dots are formed on the paper, and printing is performed (S206). If the printing is not completed, the process returns to step S202 (S207). By repeating this, the paper is conveyed intermittently. Then, during the intermittent conveyance of the paper, ink is ejected from the moving nozzles, and dots are formed on the paper to perform printing. The determination of the end of printing in step S207 can be made, for example, based on the accumulated transport amount Fa. According to this embodiment, the same effect as that of the above-described embodiment can be obtained.
[0108]
<About the timing of correction 2>
In the above-described embodiment, the correction amount for the target carry amount is determined based on the information on the carry amount. However, the determination of the correction amount is not limited to the above-described embodiment, and may be based on another determining factor. In short, the determination of the correction amount may be based on information on the transport performed by the transport unit before the transport is performed.
[0109]
FIG. 23 is a flowchart showing the timing for correcting the carry amount according to another embodiment. In this embodiment, the number of times of intermittent conveyance is a determining factor of the correction amount. Specifically, the carry amount is corrected once every n carrying times. The operation of the printer described below is controlled by the control unit 60 (or controlled by a printer driver).
[0110]
First, the state of “START” in the flowchart is a state in which the leading end of the paper S is detected by the paper width sensor 54 and is conveyed from that position to the printing start position. The count i at this time is zero (S301).
Next, 1 is added to the count i (S302). This means that one transfer is performed.
Next, since one correction operation is performed for every n transports, it is determined whether or not the count i is larger than n (S303). In addition, it is considered that a conveyance error occurs by the minimum correction amount C with respect to the target conveyance amount when the conveyance is performed n times.
If the count i is smaller than n, the target transport amount F is not corrected (S304), and the paper is transported based on the target transport amount F (S305).
If the count i is larger than n, the target carry amount F is corrected to FC (S311), and the paper is carried based on the target carry amount FC (S312). In this case, since the paper transport amount F has been corrected, n is subtracted from the count i (S313).
[0111]
Next, the carriage is moved in the scanning direction, ink is ejected from the nozzles, dots are formed on the paper, and printing is performed (S321). If the printing is not completed, the process returns to step S302 (S322). By repeating this, the paper is conveyed intermittently. Further, during the intermittent conveyance of the paper, dots are formed on the paper and printing is performed. It should be noted that the determination of the end of printing in step S322 can be made from the total transport amount of the paper.
[0112]
As in the present embodiment, even if the necessity of correcting the carry amount is determined based on the number of times of intermittent carry, it is possible to prevent the dot pitch D from extremely approaching or separating. Occurrence can be suppressed.
[0113]
Note that n used in the above description need not be an integer. For example, if n = 4/3, as in the embodiment described with reference to FIG. 15, the transport amount can be corrected in three of the four transports.
[0114]
In addition, it may be determined in advance which of the n transports the correction should be performed. In this case, it is desirable to store the conditions in the memory of the printer main body, or to set the printer driver of the computer main body based on the conditions. In this way, the correction amount can be determined based on the information on the transport performed by the transport unit without determining the reference transport amount A described above. Then, similarly to the above-described embodiment, in the present embodiment, it is possible to improve the accuracy of the conveyance.
[0115]
<About correction amount>
According to the above-described embodiment, the correction amount of the target transport amount is one of the minimum correction amounts C or zero. However, the correction amount is not limited to this.
FIG. 24 is an explanatory diagram showing the timing of correction and the relationship between the correction amount and the reference transport amount A in the case where six minimum correction amounts C are corrected for four transports, as in FIG. is there. FIG. 25 is a table showing the relationship between the transport amount and the correction amount in this case. In the above-described embodiment, the number of nozzles is 7 and the target carry amount F is 7. In the present embodiment, the number of nozzles is 180 and the target carry amount F is 179 · D.
[0116]
In the present embodiment, the correction amount of the target transport amount is six of the minimum correction amounts C for four transports. Therefore, the reference carry amount A is set to F × 4/6.
When the reference carry amount A is set in this way and the target carry amount is corrected according to the flow of the above-described embodiment, the target carry amount is corrected every time the paper is carried by a carry amount that is an integral multiple of the reference carry amount. Will be done. This means that when the transport unit transports the paper intermittently, the correction amount is almost equally distributed to each transport. Since the correction of the target transport amount is evenly distributed, the image quality is improved as compared with the case where the correction of the target transport amount is unevenly distributed.
[0117]
<About printing method>
In the above-described embodiment, the correction of the transport amount when the interlaced printing method is performed has been described, but the printing method is not limited to this.
In the above-described embodiment, one raster line is formed from dots formed by ink droplets ejected from one nozzle. However, it is not limited to this. For example, one raster line may be formed using two or more nozzles (a so-called overlap printing method).
Further, it goes without saying that the correction of the transport amount in the above-described embodiment can be applied to other printing methods.
[0118]
<Conveyance amount>
In the above-described embodiment, the carry amount when the paper is carried intermittently is the constant carry amount F. However, the paper transport amount is not limited to this. For example, the transport amount may be different depending on the print mode. Further, the transport amount may be different at the upper end or the lower end of the paper. Then, the printer main body, the printer driver, and the like may be set so that the conditions for correcting the carry amount are different when the carry amount is different.
[0119]
<About the ink ejection method>
In the above-described embodiment, the ink droplet is ejected using the piezo element. However, the method of discharging ink is not limited to this. For example, ink droplets may be ejected from nozzles by generating bubbles using a heater, or ink droplets may be ejected by other methods.
[0120]
<About the nozzle>
According to the above-described embodiment, since the nozzles are provided on the head 21 and the head 21 is provided on the carriage 41, the nozzles are provided integrally with the carriage 41. However, the configuration of the nozzle and the head 21 is not limited to this. For example, a nozzle or a head may be provided integrally with the cartridge 48 (see FIG. 2) and be detachable from the carriage 41.
[0121]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the precision of conveyance of a to-be-printed material can be improved and the image quality can be improved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an overall configuration of an inkjet printer according to an embodiment.
FIG. 2 is a schematic view of the vicinity of a carriage of the inkjet printer according to the embodiment.
FIG. 3 is an explanatory diagram around a transport unit of the inkjet printer according to the embodiment.
FIG. 4 is a perspective view of the vicinity of a transport unit of the inkjet printer according to the embodiment.
FIG. 5 is an explanatory diagram of a configuration of a linear encoder.
FIG. 6 is a timing chart showing a waveform of an output signal of a linear encoder.
FIG. 7 is an explanatory diagram showing an arrangement of nozzles on a lower surface of a head.
FIG. 8 is an explanatory diagram showing how dots are formed when there is no error when the paper S is transported (reference example).
FIG. 9 is an explanatory diagram showing how dots are formed when there is an error when the paper S is transported (reference example).
FIG. 10 is an explanatory diagram illustrating how dots are formed when the carry amount of the carry unit is corrected each time when there is an error when carrying the paper S (reference example).
FIG. 11 is an explanatory diagram showing a state of occurrence of print stripes (banding) in FIGS. 9 and 10 (reference example).
FIG. 12 is a flowchart showing the timing for correcting the carry amount according to the embodiment.
FIG. 13 is an explanatory diagram showing how dots are formed in the embodiment.
FIG. 14 is an explanatory diagram showing a state in which the occurrence of printing stripes (banding) is suppressed.
FIG. 15 is a table showing a relationship between a transport amount and a correction amount.
FIG. 16 is a graph showing a relationship between an accumulated error δT and the number of times of conveyance.
FIG. 17 is an explanatory diagram illustrating a relationship between a correction timing and a correction amount and a reference conveyance amount A;
FIG. 18 is an explanatory diagram showing an external configuration of a computer system.
FIG. 19 is a block diagram showing a configuration of the computer system shown in FIG.
FIG. 20 is an explanatory diagram illustrating a user interface of the printer driver.
FIG. 21 is an explanatory diagram of a format of print data supplied from a computer main body to a printer.
FIG. 22 is a flowchart according to another embodiment.
FIG. 23 is a flowchart in another embodiment.
FIG. 24 is an explanatory diagram showing the timing of correction and the relationship between the correction amount and the reference conveyance amount in a case where six minimum correction amounts C are corrected for four conveyances, as in FIG. 17; .
FIG. 25 is a table showing a relationship between a transport amount and a correction amount in the case of FIG. 24;
[Explanation of symbols]
10 Paper transport unit
11A Paper insertion slot
11B Roll paper insertion slot
13 Paper feed roller
14 Platen
15 Paper feed motor (PF motor)
16 Paper feed motor driver (PF motor driver)
17A paper feed roller
17B paper ejection roller
18A, 18B Free roller
20 Ink ejection unit
21 head
22 Head Driver
30 Cleaning unit
31 Pump device
32 pump motor
33 Pump motor driver
35 Capping device
40 carriage unit
41 carriage
42 Carriage motor (CR motor)
43 Carriage motor driver (CR motor driver)
44 pulley
45 Timing belt
46 Guide Rail
50 measuring instruments
51 linear encoder
511 Linear scale
512 detector
512A light emitting diode
512B collimator lens
512C detection processing unit
512D photodiode
512E signal processing circuit
512F comparator
52 Rotary encoder
53 Paper detection sensor
54 Paper width sensor
60 control unit
61 CPU
62 timer
63 Interface section
64 ASIC
65 memory
66 DC controller
67 Host computer

Claims (19)

A transport mechanism for transporting the printing medium according to the target transport amount is provided,
A printing apparatus for printing the printing medium by intermittently transferring the printing medium by the transfer mechanism,
A printing apparatus, wherein a correction amount for the target transport amount during intermittent transport is determined based on information on transport performed by the transport mechanism before the transport is performed. The printing device according to claim 1,
The information includes information on a transport amount of the printing medium performed by the transport mechanism. 3. The printing device according to claim 2, wherein
The information on the transport amount includes information on an accumulated transport amount obtained by accumulating the transport amount of the printing medium performed by the transport mechanism. The printing device according to claim 3, wherein
The correction amount is determined based on the accumulated carry amount before carrying, and the carry amount obtained by further accumulating the target carry amount on the accumulated carry amount. The printing apparatus according to claim 3, wherein:
The correction amount is determined according to a quotient obtained by dividing the accumulated carry amount by a reference carry amount as a reference. 3. The printing device according to claim 2, wherein
The information on the transport amount includes information on an excess transport amount transported by the transport mechanism exceeding a predetermined transport amount. The printing device according to claim 6,
The correction amount is determined based on a value obtained by adding the excess carry amount to the target carry amount. The printing device according to claim 6,
The predetermined carry amount is an integral multiple of a reference carry amount serving as a reference. 9. The printing device according to claim 8, wherein:
Each time the reference transport amount is transported, the target transport amount is corrected. The printing device according to claim 1,
The information includes information on the number of intermittent transports performed by the transport mechanism. The printing device according to claim 10,
The ratio of the correction to the number of times of conveyance is set in advance,
The correction amount is determined based on the number of times of the conveyance and the ratio of the correction. The printing device according to claim 5, wherein:
The reference transport amount is set based on information on the printing medium. The printing device according to claim 5, wherein:
The reference transport amount is set based on a ratio of correction to the transport amount performed by the transport mechanism. The printing device according to claim 5, wherein:
The reference carry amount is set based on a print mode. The printing apparatus according to any one of claims 1 to 14,
Further comprising a detector for detecting the transport amount of the printing medium transported by the transport mechanism,
The correction amount is an integral multiple of the minimum transport amount detectable by the detector. A transport mechanism for transporting the printing medium according to the target transport amount is provided,
A printing apparatus for printing the printing medium by intermittently transferring the printing medium by the transfer mechanism,
The correction amount for the target transport amount during intermittent transport is determined based on information about transport performed by the transport mechanism before performing the transport,
The information about the transport includes information about the transport amount of the printing medium performed by the transport mechanism,
The information on the transport amount includes information on an excess transport amount transported by the transport mechanism exceeding a predetermined transport amount,
The correction amount is determined based on a value obtained by adding the excess carry amount to the target carry amount,
The predetermined transport amount is an integral multiple of the reference transport amount serving as a reference,
Each time the transport of the reference transport amount is performed, the correction of the target transport amount is performed,
The reference transport amount is set based on information about the printing medium, a ratio of correction to the transport amount performed by the transport mechanism, and a print mode,
Further comprising a detector for detecting the transport amount of the printing medium transported by the transport mechanism,
The printing apparatus according to claim 1, wherein the correction amount is an integral multiple of a minimum transport amount detectable by the detector. A transport mechanism for transporting the printing medium according to the target transport amount is provided,
A printing method for printing the printing medium by intermittently transferring the printing medium by the transfer mechanism,
A printing method, wherein a correction amount for the target transport amount during intermittent transport is determined based on information on transport performed by the transport mechanism before the transport is performed. A transport mechanism for transporting the printing medium according to the target transport amount is provided,
A printing apparatus that prints the printing medium by intermittently transferring the printing medium by the transfer mechanism,
A program for realizing a function of determining a correction amount for the target transport amount during intermittent transport based on information on transport performed by the transport mechanism before the transport is performed. A computer body, and a transport mechanism for transporting the printing medium according to the target transport amount,
A computer system for printing the printing medium by intermittently transferring the printing medium by the transfer mechanism,
A computer system, wherein a correction amount for the target transport amount during intermittent transport is determined based on information on transport performed by the transport mechanism before the transport is performed.

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