JP2003266654A - Printer, printing method, program and computer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform highly accurate printing by taking account of the average speed of a nozzle at the time of calculation of the positional shift of shooting based on the moving speed of the nozzle. <P>SOLUTION: In the printer for printing on a body to be printed by ejecting ink intermittently thereto from a moving ink ejecting part, moving speed of the ink ejecting part is detected sequentially and the timing of intermittent ejection of ink from the ink ejecting part is controlled based on a plurality of detected speeds. According to the printer, ink can be shot at a correct position even if an error is included in the detected speed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus and a printing method for printing by intermittently ejecting ink onto 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]

2. Description of the Related Art As a printing apparatus for printing an image on various printing materials such as paper, cloth, and film, an ink jet printer is known which discharges ink intermittently for printing.
In an inkjet printer, a nozzle that ejects ink ejects ink while moving. Therefore, the ejected ink droplets fly between the nozzle and the printing medium according to the law of inertia while moving in the moving direction of the nozzle at the moving speed of the nozzle. Therefore, the ink droplets land on the paper at positions displaced from the nozzle positions when the ink droplets are ejected in the nozzle movement direction. Therefore, in the conventional inkjet printer, the moving speed of the nozzle is detected, the deviation of the landing position is calculated based on the detected moving speed of the nozzle, and printing is performed.

[0003]

However, when an error is included in the detection result of the moving speed of the nozzle, if the deviation of the landing position of the ink droplet is calculated based on the moving speed including the error, the ink Will deviate from the correct position and land on the printing medium. In particular, when the moving speed of the nozzle is detected based on the output of the encoder, if the resolution of the encoder is low, the speed is detected stepwise, and thus the error in speed detection may be large. If the deviation of the landing position of the ink droplet is considered based on the detected moving speed while the large detection error is included, the ink deviates from the accurate position and land on the printing medium. Therefore, an object of the present invention is to control the timing of ejecting ink droplets based on a plurality of detection results in order to land the ink at the correct position.

[0004]

A main invention for achieving the above object is to provide a printing apparatus for intermittently ejecting ink from a moving ink ejecting section to perform printing on an object to be printed. The speed of movement is detected sequentially,
It is characterized in that the timing of intermittent ejection of the ink from the ink ejection unit is controlled based on a plurality of the detected speeds. For other features of the invention,
This will be made clear by the description of the present specification and the accompanying drawings.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION === Outline of Disclosure === At least the following matters will be made clear by the present specification and the description of the accompanying drawings.

In a printing apparatus that prints on a printing medium by intermittently ejecting ink from a moving ink ejecting unit, the moving velocity of the ink ejecting unit is sequentially detected, and a plurality of the detected speeds are obtained. A printing apparatus, characterized in that the timing of intermittent ejection of the ink from the ink ejection unit is controlled based on the above. According to such a printing apparatus, it is possible to reduce the deviation of the ink landing position even if the detected speed has an error.

In the printing apparatus, an average speed is calculated based on the plurality of detected speeds, and the ink is intermittently ejected from the ink ejecting unit based on the calculated average speed. It is desirable to control the timing of. According to such a printing apparatus, the timing of ink ejection is controlled based on the average speed obtained from a plurality of detected signals, so that even if there is an error in the detected signals, the ink landing position It is possible to reduce the deviation.

In the printing apparatus, when the calculated average speed is slower than the reference speed, the ink ejection timing when the ink ejection unit is moving at the reference speed, and In comparison, it is desirable to eject the ink at a delayed timing. Further, in such a printing apparatus, it is desirable that the timing at which the ink is ejected be delayed as the calculated average speed is slower. Further, in such a printing apparatus, the delay amount of ink ejection is calculated based on the calculated average speed, and the ink ejection unit delays the delay amount from a signal serving as a reference for the timing of ejecting ink. ,
It is desirable to eject ink. According to such a printing apparatus, the ink can be landed at the correct position.

In the printing apparatus, the acceleration of the ink ejecting unit is calculated based on the plurality of detected velocities, and the ink is intermittently ejected from the ink ejecting unit based on the calculated acceleration. It is desirable to control the discharge timing. According to such a printing apparatus, the ink can be landed at the correct position even when the ink ejection unit is accelerating and decelerating.

Further, it is preferable that the printing apparatus has a memory, and the detected speed is stored in the memory.

Further, in the printing apparatus, the moving speed of the ink ejecting section is detected by an encoder. According to such a printing apparatus, it is possible to perform printing while reducing the error in speed detection even if the resolution of the encoder is low.

In a printing apparatus for printing ink on a printing medium by intermittently ejecting ink from a moving ink ejecting section, the moving speed of the ink ejecting section is sequentially detected and detected using an encoder. The speed is stored in a memory, an average speed is calculated based on the plurality of detected speeds, an acceleration of the ink ejection unit is calculated based on the plurality of detected speeds, and the calculated average is calculated. Based on the speed and the acceleration, controlling the timing of intermittent ejection of the ink from the ink ejection unit, when the calculated average velocity is slower than a reference velocity, the ink ejection unit, The ink is ejected at a delayed timing compared to the timing of ink ejection when moving at the reference speed, and the slower the calculated average speed is, the more the Printing apparatus characterized by timing of discharge delay the. According to such a printing apparatus, the ink can be landed at the correct position.

In a printing method in which ink is intermittently ejected from a moving ink ejecting section to print on a printing medium, a step of sequentially detecting a moving speed of the ink ejecting section, and a plurality of the detected values are detected. Controlling the timing of intermittent ejection of the ink from the ink ejecting section based on the speed. According to such a printing method, the ink can be landed on the correct position.

A plurality of the detected functions are provided, which have a function of causing a printing apparatus that ejects ink intermittently from a moving ink ejecting unit to print on a printing medium to sequentially detect the moving speed of the ink ejecting unit. A program that realizes a function of controlling a timing of intermittent ejection of the ink from the ink ejecting unit based on a speed. According to such a program, the printing apparatus can be controlled so that the ink is landed at the correct position.

A computer system comprising a computer main body and a printing device connectable to the computer main body, wherein the printing device intermittently ejects ink from a moving ink ejection unit to print on a printing medium. And sequentially detecting the moving speed of the ink ejecting unit, and controlling the timing of intermittent ejection of the ink from the ink ejecting unit based on a plurality of the detected velocities. Computer system to do. With such a computer system, highly accurate printing can be performed.

=== Outline of Printing Apparatus (Inkjet Printer) === <Regarding Configuration of Inkjet Printer> FIGS. 1 and 2
An outline of an inkjet printer will be described as an example of a printing apparatus with reference to FIGS.
Note that FIG. 1 is an explanatory diagram of the overall configuration of the inkjet printer of the present embodiment. Further, FIG. 2 is a schematic diagram around the carriage of the inkjet printer of the present embodiment. Further, FIG. 3 is an explanatory diagram of the periphery of the transport unit of the inkjet printer of the present embodiment. The inkjet printer of the present embodiment includes a paper transport unit 10, an ink discharge unit 20, a cleaning unit 30, a carriage unit 40, a measuring instrument group 50, and a control unit 60.

The paper transport unit 10 feeds, for example, paper, which is a printing medium, to a printable position, and in printing, in a predetermined direction (a direction perpendicular to the paper surface in FIG. 1 (hereinafter, referred to as paper feeding direction)). This is for moving the paper by the moving amount. The paper transport unit 10 includes a paper feed insertion port 11A, a paper discharge port 11B, a paper feed motor 12, a paper feed roller 13,
A platen 14, a paper feed motor (hereinafter referred to as a PF motor) 15, 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 18.
B, a gear 19A, a gear 19B, and a gear 19C. The paper feed insertion port 11 is where the paper to be printed is inserted. The paper feed motor 12 is a motor that conveys the paper inserted in the paper feed insertion port 11 into the printer, and is configured by a DC motor. The paper feed roller 13 has a paper feed insertion port 11
A roller that conveys the paper inserted in the printer into the printer.
It is driven by the paper feed motor 12. The platen 14 is
The paper S being printed is supported. The PF motor 15 is a motor that sends out a paper to be printed, for example, paper in the paper feeding direction
It is composed of a DC motor. The PF motor driver 16
This is for driving the PF motor 15. The paper feed roller 17A is a roller that feeds the paper S conveyed 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 with the paper feed roller 17A. The paper discharge roller 17B is a roller that discharges the paper S for which printing has finished to the outside of the printer. 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 with the paper discharge roller 17B. Gear 19A, gear 19B
The gear 19C and the gear 19C are for transmitting the driving force of the PF motor 15 to the paper ejection roller 17B because the paper ejection roller 17B is driven by the PF motor 15. Paper exit 1
In 1B, the printed paper is discharged to the outside of the printer.

The ink ejection unit 20 is for ejecting ink onto a printing medium such as paper. The ink ejection unit 20 has a head 21 and a head driver 22. The head 21 has a plurality of nozzles, which are ink ejection portions, and ejects ink intermittently from each nozzle. The head driver 22 drives the head 21 to intermittently eject ink from the head. The timing of ejecting ink will be described later.

The cleaning unit 30 includes a head 21.
This is to prevent clogging of the nozzle. The cleaning unit 30 includes a pump device 31 and a capping device 35. The pump device sucks ink from the nozzles in order 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 prevents the nozzles of the head 21 from being clogged so that the head 21 does not print (standby).
The nozzle of is sealed.

The carriage unit 40 is for moving the head 21 in a predetermined direction (left and right direction of the paper surface in FIG. 1 (hereinafter, referred to as scanning direction)). The carriage unit 40 includes a carriage 41, a carriage motor (hereinafter referred to as CR motor) 42, and a carriage motor driver (hereinafter referred to as 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 (thus, the nozzles of the head 21 intermittently eject ink while moving along the scanning direction). The carriage 41 also includes an ink cartridge 48 that contains ink.
Is detachably held. The CR motor 42 is a motor that moves the carriage in the scanning direction, and is composed of a DC motor. The CR motor driver 43 is for driving the CR motor 42. Pulley 44 is CR
It is attached to the rotary shaft of the motor 42. The timing belt 45 is driven by the pulley 44. The guide rail 46 guides the carriage 41 in the scanning direction. The details of the movement of the carriage 41 will be described later.

The measuring instrument group 50 includes a linear encoder 5
1, a rotary encoder 52, and a paper detection sensor 5
3 and the gap sensor 54. The linear encoder 51 is for detecting the position of the carriage 41. The rotary encoder 52 is the PF motor 1
5 is for detecting the rotation amount. The configuration of the encoder will be described later. Paper detection sensor 53
Is for detecting the position of the end of the printed paper. The gap sensor 54 is for detecting the distance PG from the nozzle to the paper S. The configuration of the gap sensor will be described later.

The control unit 60 is for controlling the printer. The control unit 60 includes a CPU 61
, Timer 62, interface unit 63, ASI
It has a C 64, a memory 65, and a DC controller 66. The CPU 61 is for controlling the entire printer, and gives a control command 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 to the CPU 61. The interface unit 63 transmits / receives data to / from a host computer 67 provided outside the printer. The ASIC 64 controls the print resolution, the head drive waveform, and the like based on print information sent from the host computer 67 via the interface unit 63. Memory 65 is ASIC 64 and CP
It is for securing an area for storing the U61 program, a work area, and the like, and includes PROM, RAM, and EEPRO.
It has a storage means such as M. The DC controller 66 is C
The PF motor driver 16 and the CR motor driver 43 are controlled based on the control command sent from the PU 61 and the output from the measuring instrument group 50.

<Regarding Encoder Configuration> FIG. 4 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 detector 512. The linear scale 511 has a predetermined interval (for example,
Slits are provided every 1/180 inch (1 inch = 2.54 cm) and are fixed to the printer body side.

The detector 512 is provided so as to face the linear scale 511, and is provided on the carriage 41 side. The detection unit 512 includes a light emitting diode 512A,
It includes a collimator lens 512B and a detection processing unit 512C, and the detection processing unit 512C has a plurality of (for example, 4
Number of photodiodes 512D and the signal processing circuit 51
2E and two comparators 512Fa and 512Fb.

The light emitting diode 512A emits light when the voltage Vcc is applied via the resistors at both ends, and this light is incident on the collimator lens. Collimator lens 512
B makes the light emitted from the light emitting diode 512A 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 is incident on each photodiode 512D. Photodiode 512D
Converts the incident light into an electric signal. The electric signal output from each photodiode is the comparator 512F.
a, 512Fb, and the comparison result is output as a pulse. Then, the comparators 512Fa, 5
Pulse ENC-A and pulse E output from 12Fb
NC-B is the output of the linear encoder 51.

FIG. 5 is a timing chart showing waveforms of two types of output signals of the linear encoder 51. FIG. 5A is a timing chart of the waveform of the output signal when the CR motor 42 is rotating normally. FIG. 5B shows
It is a timing chart of the waveform of the output signal when the CR motor 42 is reversed.

As shown in FIGS. 5A and 5B, whether the CR motor 42 is rotating normally or reversing,
The pulse ENC-A and the pulse ENC-B have a phase of 90.
Deviated. When the CR motor 42 is rotating normally, that is, when the carriage 41 is moving in the main scanning direction, the phase of the pulse ENC-A is 90 degrees greater than that of the pulse ENC-B, as shown in FIG. 5A. It is progressing. on the other hand,
When the CR motor 42 is reversing, the pulse ENC-A is 90 times faster than the pulse ENC-B as shown in FIG. 5B.
The phase is delayed by degrees. In one cycle T of each pulse, the carriage 41 has a slit interval of the linear scale 511 (for example, 1/180 inch (1 inch = 2.54c).
m)) is equal to the time it takes to travel.

The position of the carriage 41 is detected as follows. First, regarding the pulse ENC-A or ENC-B, a rising edge or a falling edge is detected,
Count the number of detected edges. The position of the carriage 41 is calculated based on this count number. The count number is incremented by "+1" when one edge is detected while the CR motor 42 is rotating normally, and the CR motor 4
If one edge is detected when 2 is inverted, "-1" is added. Since the cycle 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 linear encoder 5 in this case
The resolution of 1 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 each cycle of the pulse ENC-A and the pulse ENC-B is equal to the slit interval of the linear scale 511, and the phases of the pulse ENC-A and the pulse ENC-B are deviated by 90 degrees, the rising edge of each pulse is increased. If a falling edge and a falling edge are detected and the number of the detected edges is counted, the count number “1” is calculated by
Corresponds to 1/4 of the slit interval of. Therefore, by multiplying the count number by 1/4 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 1/4 of the slit interval of the linear scale 511. However, the position of the carriage 41 in this embodiment, which will be described later, is detected by using only one pulse in order to simplify the description.

The velocity Vc of the carriage 41 is detected as follows. First, the pulse ENC-A or ENC-B
For, the rising edge or the falling edge is detected. On the other hand, the time interval between the edges of the pulses is counted by the timer counter. From this count value, the cycle T
(T = T1, T2, ...) Is required. When the slit spacing of the linear scale 511 is λ, the speed of the carriage 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 the edges corresponding to 1/4 of the slit interval of the linear scale 511 is counted by the timer counter. From this count value, the cycle T (T
= T1, T2, ...) is required. When the slit spacing of the linear scale 511 is λ, the carriage velocity Vc can be sequentially obtained as Vc = λ / (4T). However, the speed of the carriage 41 in this embodiment to be described later is assumed to be detected using only one pulse in order to simplify the description.

In the rotary encoder 52,
Linear scale 511 of linear encoder 51 is PF
The other configuration is almost the same as that of the linear encoder 51, except that it is a rotating disk that rotates according to the rotation of the motor 15.

=== Detection of PG === In this embodiment, the distance PG from the nozzle to the paper is detected in order to calculate a reference position described later and to calculate the timing of ink ejection (described later). is doing. FIG. 6 is an explanatory diagram of the gap sensor that detects the distance PG from the nozzle to the paper.

In the figure, the gap sensor 54 has a light emitting section 541 and two light receiving sections (first light receiving section 542 and second light receiving section 543). The light emitting unit 541 has a light emitting diode and irradiates the paper S, which is the printing target, with light.
The first light receiving unit 542 has a light receiving element that outputs an electric signal according to the amount of received light. The second light receiving unit 543 has a first
It has a light receiving element similar to the light receiving section 542. The second light receiving unit 543 is different from the first light receiving unit 542 in comparison with the light emitting unit 54.
It is provided at a position far from 1.

The light emitted from the light emitting section 541 is incident on the paper S. The light incident on the paper S is reflected by the paper. The light reflected by the paper S enters the light receiving element. The light incident on the light receiving element is converted by the light receiving element into an electric signal according to the amount of incident light.

When the distance PG from the nozzle to the paper is small, the light reflected by the paper S1 is mainly the first light receiving portion 54.
2 and only diffused light is incident on the second light receiving unit 543. Therefore, the output signal of the first light receiving unit 542 is
It becomes larger than the output signal of the light receiving unit 543.

On the other hand, when the distance PG from the nozzle to the paper is large, the light reflected by the paper S2 mainly enters the second light receiving portion 543 and only the diffused light enters the first light receiving portion 542. Therefore, the output signal of the second light receiving unit 543 is
It becomes larger than the output signal of the first light receiving unit 542.

Therefore, if the relationship between the output signal ratio of the light receiving section and the distance PG is obtained in advance, the distance PG from the nozzle to the paper can be detected based on the ratio of the output signal of the light receiving section. is there. In this case, it is preferable to store information about the relationship between the ratio of the output signal of the light receiving unit and the distance PG in the memory 65 as a table. When the distance PG from the nozzle to the paper becomes small, it is possible that the paper S1 is thick paper. When the distance PG from the nozzle to the paper is large, it is possible that the paper S2 is thin paper. By the way, as will be described later, "reference distance P
“Gs” may not be detected by the sensor but may be predetermined. In this case, the reference distance PGs is
It is set to a value larger than the distance PG detected by the sensor.

In this embodiment, the distance PG is detected using the gap sensor 54 as described above.
Is not limited to one location, and the distance PG may be detected at a plurality of locations as described below.

<Detection of Plural PGs in the Scanning Direction> FIG. 7 is an explanatory diagram showing that the gap sensor 54 measures the distances PG at plural points in the scanning direction.
FIG. 7 is a view seen from the paper feed direction, and the left-right direction of the paper surface is the scanning direction. In the figure, the same constituent elements are given the same reference numerals, and the description thereof will be omitted.

In the figure, a gap sensor 54 is provided on the carriage 41. Therefore, the gap sensor 54 can move in the scanning direction as the carriage moves. Therefore, the gap sensor 54
Can detect the distance PG at a plurality of points along the operation direction. Since the gap sensor 54 can detect the distance PG for each area along the scanning direction, the ink ejection timing (described later) can also be controlled for each area along the scanning direction. Therefore, even if the paper S is bent at the time of printing, the timing of ink ejection can be controlled for each area along the scanning direction. Therefore, even if the nozzle intermittently ejects ink along the scanning direction, it is highly accurate. Printing can be performed. The cause of the paper S bending in the scanning direction is considered to be the influence of ink application during printing.

<Detection of a plurality of PGs along the paper feed direction>
FIG. 8 is an explanatory diagram showing that the gap sensor 54 measures the distance PG at a plurality of points along the paper feed direction. FIG. 8 is a view seen from the scanning direction, and the left and right direction of the paper surface is the paper feeding direction. In the figure, the same constituent elements are given the same reference numerals, and the description thereof will be omitted.

In the figure, a plurality of gap sensors are
They are provided on the carriage side by side in the paper feed direction. Therefore, it is possible to detect the distance PG at a plurality of points along the paper feed direction based on the output of each gap sensor.

If the gap sensor 54 can measure the distance PG at a plurality of points along the paper feed direction, since a plurality of nozzles are arranged in the paper feed direction, the ink ejection timing for each nozzle (described later). ) Will be able to control.

Therefore, even if the paper S is curved at the time of printing, the timing of ink ejection can be controlled for each nozzle, so that highly accurate printing can be performed.

The cause of the paper S bending in the paper feed direction is considered to be the influence of the rotational deviation between the paper feed roller 17A and the paper discharge roller 17B. Further, when the head becomes large and the nozzles are arranged long in the paper feeding direction, the deviation of the distance PG from each nozzle to the paper S becomes large. In such a case, if the timing of ink ejection can be controlled for each nozzle, it is effective for highly accurate printing.

=== Detection of Ink Ejection Speed === In the present embodiment, the ink ejection speed Vi is detected in order to calculate the ink ejection timing (described later).
The speed of ink ejection generally increases as the weight of ink increases. Therefore, when the printer changes the ink ejection amount, the ink ejection speed Vi changes based on the ink ejection amount. For example, when the printer forms large dots and small dots on paper, the ink ejection speed when forming the large dots is higher than the ink ejection speed when forming the small dots. Therefore, in the present embodiment, information regarding the ejection speed of ink corresponding to each dot is stored in the memory 65 as a table, and the ejection speed of ink is detected based on this table. That is, when the printer performs the printing operation based on the print information, the ejection amount of the ink formed at the time of printing is obtained based on the print information, and the table stored in the memory 65 is referred to based on the obtained ejection amount. , The speed of ink ejection is detected based on the table. It should be noted that this table of information regarding the ejection speed of ink may be further provided for each ink color.

By the way, as will be described later, "reference discharge speed Vi
"s" may be a predetermined one, not the detected one. In this case, the reference ejection speed Vis is set to be a value equal to or lower than the detected ink ejection speed Vi (for example, a value equal to or lower than the ejection speed of a small dot).

=== Variance History of Carriage === FIG. 9 is a graph showing the change over time of the moving speed of the carriage of this embodiment. In the figure, the vertical axis represents the moving speed Vc of the carriage, and the horizontal axis represents the time t.

As shown in the figure, the carriage 41 is accelerated from a stopped state (t = 0) to a predetermined speed Va (0 <t <t1) and scans at a constant speed (hereinafter referred to as scanning speed). (T1 <t <t2), the vehicle decelerates and stops (t2 <t <t3). Then, next, similar acceleration movement, scanning movement, and deceleration movement are performed in the opposite direction. By repeating this, the carriage 41 moves back and forth in the scanning direction.

Printing may be performed only in the area where the carriage 41 moves at the scanning speed (hereinafter referred to as the constant speed area). However, if the printing is performed using only the constant speed area, it is necessary to secure the constant speed area for the width of the printing area, and the printer becomes large. Therefore, in the present embodiment, even in the area where the carriage 41 accelerates and decelerates (hereinafter referred to as the acceleration / deceleration area),
It is supposed to print.

On the other hand, since the carriage is moving at a speed lower than the scanning speed during acceleration / deceleration, if ink is ejected in the acceleration / deceleration area at the same timing as in the scanning area, the ink droplets will be positioned below the target landing position on the paper. Land in the foreground. That is, when printing is performed in the acceleration / deceleration area, it is necessary to eject the ink with a delay from the timing of ejecting the ink in the scanning area. The timing of this delay will be described later. In the present embodiment, printing can be performed even in the acceleration / deceleration area, so that the size of the printer can be reduced.

By the way, the "reference speed Vs" described later is
Instead of being detected, a predetermined one may be used. In this case, the reference speed Vs is set to a value higher than the moving speed Vc of the carriage.

=== Timing of Ink Ejection === <Regarding the Trace of Ink Drops> FIG. 10 is an explanatory diagram of the traces of ink drops when ink is ejected from the nozzles. FIG. 10A is an explanatory diagram of the locus of ink droplets when the nozzles are stopped (the carriage 41 is stopped). 10B and 10C show
FIG. 7 is an explanatory diagram of a trajectory of an ink droplet when a nozzle is moving (a carriage 41 is moving). In reality, the ink is intermittently ejected from the nozzle, but the number of ink droplets in FIG. 10 is limited in order to simplify the description.

In FIG. 10A, since the nozzle is stopped, the ink droplet lands on the paper just below the position of the nozzle when the ink droplet is ejected. When the velocity (ink ejection velocity) in the vertical direction (direction toward the paper) of the ink droplets ejected from the nozzle is Vi and the distance (gap) from the nozzle to the paper is PG, the ink droplet is ejected,
After the time PG / Vi, it hits the paper. The time from the ejection of the ink droplet to the landing on the paper is referred to as the "flying time". The ink flight time when the ink ejection speed is the reference speed (hereinafter referred to as the reference ink ejection speed) Vis and the distance from the nozzle to the paper is the reference distance (hereinafter referred to as the reference distance) PGs Will be referred to as the “reference flight time”.

In FIG. 10B, the carriage is moving in the scanning direction (left-right direction on the paper) at a reference speed (hereinafter referred to as reference speed) Vs. The speed of the carriage 41 is V
If s, the nozzle is also moving in the scanning direction at a speed of Vs. On the other hand, if the vertical velocity of the ink droplets is the reference ink ejection velocity Vis and the distance from the nozzle to the paper is the reference distance PGs, the ink droplets land on the paper after the reference flight time has elapsed after being ejected. Then, due to the law of inertia, the ink droplet lands on the paper at a position displaced in the scanning direction by a distance Vs × PGs / Vis from the position of the nozzle when the ink droplet is ejected. Therefore, in order to land the ink droplets on a predetermined position on the paper (hereinafter referred to as the target landing position), the nozzle is separated from the landing target position by a distance Vs × P.
It is necessary to eject an ink droplet from the nozzle at a timing when the position is Gs / Vis.

In the present embodiment, the position where the nozzle ejects the ink droplet in order to land the ink droplet on the landing target position when the carriage 41 is moving at the reference velocity Vs is called the "reference position". To In other words, the carriage 41 moves at the reference speed Vs, the distance from the nozzle to the paper is the reference distance PGs, and when the ink droplets are ejected at the reference ink ejection speed Vis, the carriage 41 moves from the nozzle at the timing to reach the reference position. If you eject ink drops,
Ink droplets can be landed at the target landing positions to form dots at predetermined positions on the paper. In the present embodiment, the reference position is calculated as a position before Vs × PGs / Vis from the landing target position.

In FIG. 10C, the carriage 41 moves at a speed Vc lower than the reference speed Vs, the distance PG from the nozzle to the paper is smaller than the reference distance PGs, and the ink ejection speed Vi is higher than the reference ink ejection speed Vis. Ink droplets are being ejected. In this case, the position where the ink drops land is
Vc x PG / from the position of the nozzle when ink droplets are ejected
The position is shifted by Vi in the scanning direction. If ink is ejected at the reference position, the ink droplet lands in front of the landing target position by (Vs × PGs / Vis) − (Vc × PG / Vi). Therefore, in order to land the ink droplet at the landing target position (to form a dot at a predetermined position on the paper), the nozzle is (Vs × PGs / Vis) −
It is necessary to eject the ink droplets from the nozzle at the timing when the reference position is passed by (Vc × PG / Vi). In other words, the carriage 41 moves at a speed lower than the reference speed Vs, and the distance PG from the nozzle to the paper is the reference distance PG.
When ink droplets are ejected at an ink ejection speed Vi that is smaller than s and faster than the reference ink ejection speed Vis, in order to make the ink droplets land at the landing target position, the carriage 41 should be ejected at the reference position. It is necessary to delay by a predetermined time after reaching.

That is, in this embodiment, when the delay timing is obtained, the carriage moving speed Vc,
The distance PG from the nozzle to the paper and the ink ejection speed Vi are taken into consideration. If the preset reference speed Vs is faster than the scanning speed Va, the timing of ink ejection described below can be applied not only to the acceleration / deceleration area but also to the scanning area.

<Regarding Delay Timing> As described above, in order to land the ink droplet on the landing target position, the nozzle moves the reference position to (Vs × PGs / Vis) − (Vc × P).
G / Vi) at a delayed timing that passes by,
It is necessary to eject ink drops from the nozzle. Therefore, in the present embodiment, as described below, the period of the pulse ENC of the linear encoder 51 is divided into n, the m-th step corresponding to the delay amount is calculated, and the ejection timing of the ink droplet is controlled.

FIG. 11A shows the waveform of the output signal of the linear encoder 51. The output of the pulse ENC for one cycle from the linear encoder 51 means that the carriage 41 moves within the slits of the linear scale 511. For example, the linear scale 511
When the slit interval is 1/180 inch and the linear encoder 51 outputs a pulse signal for one cycle, it means that the carriage 41 has moved 1/180 inch. That is, the linear encoder 51 in this case
The resolution of the position detection of the carriage 41 by
It is 0 inches.

In FIG. 11B, the carriage 41 has a reference speed V.
The distance from the nozzle to the paper is the reference distance PGs.
Is a head drive signal when ink droplets are ejected at the reference ink ejection speed Vis. The nozzles of the head 21 eject ink according to the timing when the head drive signal is input. Since the carriage 41 in this case is moving at the reference speed Vs, the head drive signal is issued when the carriage 41 reaches the reference position.
Since the position of the carriage 41 is detected within the resolution of the linear encoder 51, the head drive signal is generated at the same timing as the rising edge of the pulse signal of the linear encoder 51.

In FIG. 11C, the carriage 41 moves at the speed Vc.
(<Vs), the distance from the nozzle to the paper is PG
(<PGs), and the ink ejection speed is Vi (> Vi).
s) is a head drive signal. The nozzles of the head 21 eject ink according to the timing when the head drive signal is input. The head drive signal in this case is issued with a delay after the carriage 41 reaches the reference position. That is, the head drive signal of FIG. 11C is
Comparing with the timing of the head drive signal of FIG. 11B,
It is issued at a delayed timing. The calculation of the speed Vc of the carriage 41 will be described later.

In this embodiment, the linear encoder 51 is used.
Of the pulse ENC is divided into n and m corresponding to the delay amount.
The stage is calculated, and the head drive signal is controlled to be emitted at the timing corresponding to the m stage. That is, first,
The movement distance λ for one cycle is divided into n. When one cycle is divided into n, the slit interval of the linear scale 511 is λ.
Then, one stage corresponds to λ / n. For example, when one cycle is divided into 128, if the slit interval of the linear scale 511 is 1/180 inch, one step is about 1.1 μm.
Equivalent to. Here, it is desirable that n is a power of 2 for convenience of calculation of the control unit 60.

Next, the number of stages required to delay the head drive signal is calculated. If the timing corresponding to the delay amount is the mth stage, m = (correction distance) /
(Λ / n). The correction distance is as described above.
(Vs × PGs / Vis) − (Vc × PG / Vi). That is, m is calculated by the following formula.

[0064]

[Equation 1] However, since m needs to be an integer, when m is not an integer in the above formula, for example, rounding down, rounding, or rounding up is performed to make m an integer.

Then, the head drive signal is issued at a time corresponding to the mth stage from the rising edge of the pulse signal of the linear encoder 51. That is, the head drive signal is emitted at a timing delayed from the rising edge of the pulse signal of the linear encoder 51 by the mth stage. As a result, ink droplets can be ejected from the nozzle at a delayed timing such that the nozzle passes the reference position by (Vs × PGs / Vis) − (Vc × PG / Vi).

As can be seen from the above equation (1), the smaller the velocity Vc of the carriage 41, the more the ink is ejected at the delayed timing. On the other hand, as the velocity Vc is higher, the ink is ejected at a timing delayed a little.
Further, as the distance PG from the nozzle to the paper is smaller, the ink is ejected at a timing with a large delay. On the other hand, as the distance PG is larger, the ink is ejected at a timing delayed a little. Further, as the vertical ejection speed Vi of the ink droplet is slower, the ink is ejected at a slightly delayed timing. On the other hand, as the ejection speed Vi is higher, the ink is ejected at a timing that is greatly delayed.

According to this embodiment, the timing of ink ejection from the nozzle is delayed from the reference position based on the carriage moving speed Vc, the distance PG from the nozzle to the paper and the ink ejection speed Vi. Is controlled. As a result, the printer of this embodiment can perform precise printing.

In the above-described embodiment, the number of ink droplets is limited to simplify the description. However, even if ink is intermittently ejected from the nozzle, each ink droplet is ejected. The timing of is controlled similarly.

=== Calculation of Average Velocity === <Regarding Average Velocity> When the velocity Vc of the carriage 41 is calculated as Vc = λ / T using the cycle T immediately before the linear encoder, the output of the linear encoder is obtained. In some cases, ink may not be landed at an accurate position if there is an error or if there is speed variation such as cogging. Therefore, in the present embodiment, a linear encoder is used to sequentially detect the moving speed of the carriage (that is, the moving speed of the nozzle), and the average speed is calculated from the plurality of detected speeds. Based on this, the delay amount m of the ink ejection timing is calculated.

FIG. 12 shows the waveform of the output signal of the linear encoder 51 when the carriage is moving. In the figure, the carriage is assumed to be in the position A. Therefore, the signals in the sections A to D are already output signals, and the signals in the sections A to X are output signals expected in the future.

In the figure, the cycle of the pulse signal of the linear encoder 51 varies due to measurement error or cogging. Therefore, if the slit spacing λ is divided by the immediately preceding period T1 to calculate Vc and the delay amount m of ink ejection in the sections A to X is calculated based on the Vc, a large error may be included. is there. Therefore, in order to calculate the delay amount m more accurately, in the present embodiment, the speed Vc in the sections A to X is calculated as follows, and the delay amount m is calculated.
Is calculated.

First, based on the period T3 of the sections D to C,
The speed V3 of the carriage in this section is detected. Similarly, the velocity V2 of the carriage in the sections C to B and the section B
The velocity V1 of the carriage at .about.A is detected. Then, the average velocity V = (V3 + V2 + V1) / 3 of the carriage is calculated based on the plurality of detected velocities. in this case,
The sequentially detected speeds of the carriage are preferably stored in a memory. The calculated average speed is regarded as the speed Vc of the carriage in the sections A to X, and is used to calculate the delay amount m. The timing of ink ejection is
The rising edge of A is used as a reference, and a delay amount m is delayed from this reference.

In the above description, the delay amount m from the reference A is calculated based on the average speed of the sections D to A. However, it may take time to calculate the delay amount m. Therefore, the speed may be detected in the section before B, the average speed and the delay amount m may be calculated in the sections B to A, and the ink may be ejected at a timing delayed from the reference A by the delay amount m.

As described above, in this embodiment, since the ink ejection timing is controlled based on the average speed of the carriage, even if there is an error in the detected speed or cycle, the deviation of the ink landing position will occur. Can be reduced.

=== Complement of carriage speed change ==
= <Regarding Calculation of Delay Amount> If the carriage is moving at a constant speed, the moving speed Vc of the carriage is Vc = λ from the pulse period T of the linear encoder 51 and the slit interval λ of the linear scale. It can be calculated as / T. However, when the carriage is moving by accelerating or decelerating, the moving speed Vc of the carriage is set to V
Even if the delay amount m of ink ejection is calculated with c = λ / T,
Since the speed of the carriage when ejecting ink is different from λ / T (that is, the period T is past), the ink cannot be landed at the target position. Therefore, in the present embodiment, in order to obtain the speed Vc of the carriage when ejecting ink, the acceleration of the carriage (that is, the acceleration of the nozzle) is calculated based on the plurality of detected speeds, and the speed is calculated based on the calculated acceleration. Vc is calculated.

FIG. 13 shows the waveform of the output signal of the linear encoder 51 when the carriage is accelerating. The carriage is assumed to be in the position A.
Therefore, the signals in the sections A to D are already output signals, and the signals in the sections A to X are output signals expected in the future. In the figure, since the carriage is accelerating, the speed gradually increases, so the cycle T gradually decreases. Therefore, the period T0 of the output signal expected in the future is expected to be shorter than the immediately preceding period T1.
Therefore, if the slit spacing λ is set to the cycle T1 (or
Vc is calculated by dividing by the period T2 before that).
If the delay amount m of ink ejection in the section A to X is calculated based on c, the delay amount will be large.

Therefore, in order to calculate a more accurate delay amount, in this embodiment, the speed Vc in the sections A to X is calculated and the delay amount m is calculated as follows. First, the speed V2 of the carriage in this section is detected based on the cycle T2 of sections C and B. Similarly, the period T of the sections B to A
Based on 1, the speed V1 of the carriage in this section is detected. The detected speed is stored in the memory. Then, the acceleration of the carriage is detected based on the detected difference between the speeds V1 and V2. If the acceleration of the carriage is known, the expected speed V0 of the carriage in the future in the sections A to X and the cycle T0 expected in the future can be calculated. If the carriage speed V0 can be calculated,
By using the speed V0 as Vc, the delay amount m can be calculated. The timing of ink ejection is A
With reference to the rising edge of, a delay amount m is delayed from this reference.

In the above description, sections C to B and sections B to
The acceleration is calculated based on the velocities V2 and V1 at A, and the delay amount m from the reference A is calculated. However, the delay amount m
It may take time to calculate. Therefore, sections D to C
And velocities V3 and V2 in sections C to B are detected, and sections B to
In A, the acceleration, V0, and the delay amount m are calculated, and the reference A
The ink may be ejected at a timing delayed by a delay amount m from. Also, the difference between V3 and V2 and V2 and V1
It is also possible to calculate the average acceleration based on the difference between the above and the calculated average acceleration, and to calculate the expected speed V0 (= Vc) of the carriage and the delay amount m in the future in the sections A to X based on the calculated average acceleration. . Further, since the speed of the carriage changes while the carriage moves by the delay amount, the speed Vc may be calculated based on the acceleration of the carriage in consideration of the delay amount.

In this embodiment, since the acceleration of the carriage is positive, the cycle T is gradually shortened and the cycle of ink ejection timing is also shortened. On the other hand, when the acceleration of the carriage is negative (when the carriage is decelerating), the cycle T gradually becomes longer, and the cycle of ink ejection timing becomes longer.

<Regarding Generation of Reference Signal 1> Ink droplets may be ejected at intervals shorter than the position detection resolution of the linear encoder 51. For example, when the resolution of the linear encoder 51 is 1/180 inch, 1
This is a case where ink is ejected at an interval of / 720 inch. In such a case, normally, a reference signal is generated at an interval obtained by dividing the pulse period T immediately before the linear encoder by, for example, 4 and ink is ejected by using the reference signal as a trigger. However, if the immediately preceding pulse period T includes a large detection error, the ink will not land at equal intervals. Therefore, in order to make the ink landing intervals equal, the future expected period T0 of the sections A to X is calculated based on the plurality of detected carriage velocities, and the calculated period T0 is equalized. A signal that serves as a reference for the timing of ejecting ink is generated so as to be divided. In this way, since the signal that is the reference of the ink ejection timing is generated based on the average of the plurality of detected signals,
Even if there is an error in the detected speed or cycle, it is possible to reduce the deviation of the ink landing position.

<Regarding Generation of Reference Signal 2> Further, when the carriage is accelerating or decelerating, if the intervals obtained by dividing the pulse period T are uniform, ink is not landed at equal intervals. Therefore, in the present embodiment, in order to make the ink landing intervals equal, the acceleration of the carriage is calculated based on a plurality of detection results of the encoder, and a signal serving as a reference for the timing of ejecting ink is generated. There is.

FIG. 14A shows the waveform of the output signal expected in the future in the sections A to X in FIG. The cycle T0 of the output signal is calculated based on a plurality of detection results of the encoder as described above.

FIG. 14B shows the waveform of the reference signal when the pulse period T0 is not divided. The reference signal shown in the figure is generated based on the rising edge of the linear encoder 51. That is, when the pulse cycle T0 is not divided, the reference signal can be generated based on the rising edge of the linear encoder 51. Therefore, in such a case, the acceleration of the carriage is not required when generating the reference signal. However, based on this reference signal, ink is ejected at the timing of the delay amount m corresponding to the acceleration of the carriage.

FIG. 14C shows the waveform of the reference signal when the pulse period T0 is divided into four. In the figure, since the carriage is accelerating, the speed gradually increases, so the interval between the reference signals Pa to Pd gradually decreases.

Here, the reference signal Pa is generated based on the rising edge of the linear encoder 51.
Then, the reference signal Pb is the time T0a from the reference signal Pa.
It is generated after passing. The calculation of the time T0a is obtained by calculating the future expected speed of the carriage between Pa and Pb based on the acceleration of the carriage. However, the detection of the acceleration of the carriage is the same as that described above. Furthermore, the times T0b and T0c are obtained based on the acceleration of the carriage, as in the calculation of the time T0a. The time between the reference signal Pd and the next reference signal does not need to be calculated. The reference signal next to the reference signal Pd is
This is because it may be generated based on the rising edge of the linear encoder 51.

The ink ejection timing is delayed by a delay amount m from each reference signal. However, the calculation of the delay amount m is the same as that described above. In this embodiment, since the acceleration of the carriage is positive, the interval between the reference signals becomes short and the cycle of ink ejection timing also becomes short. On the other hand, when the acceleration of the carriage is negative (when the carriage is decelerating), the interval of the reference signal becomes long and the cycle of ink ejection timing becomes long. As described above, if the delay amount of ink ejection and the reference signal are calculated based on the acceleration of the carriage (that is, the acceleration of the nozzles), the ink can be landed at the target position, and thus highly accurate printing can be performed. You can

=== Configuration of Computer System etc. ==
= Next, regarding the embodiment of the computer system, the computer program, and the recording medium recording the computer program, which is an example of the embodiment according to the present invention,
A description will be given with reference to the drawings.

FIG. 15 is an explanatory diagram showing the external structure of the computer system. Computer system 100
0 is a computer main body 1102 and a display device 1104.
A printer 1106, an input device 1108, and a reading device 1110. Computer 1102
In the present embodiment, is housed in a mini-tower type housing, but is not limited to this. Display device 1104
In general, a CRT (CathodeRay Tube), a plasma display, a liquid crystal display device, or the like is used, but the invention is not limited to this. Printer 11
For 06, the printer described above is used.
The input device 1108 is the keyboard 110 in this embodiment.
8A and mouse 1108B are used, but are not limited thereto. In the present embodiment, the reading device 1110 includes flexible disk drive devices 1110A and C.
Although the D-ROM drive device 1110B is used, the D-ROM drive device 1110B is not limited to this.
o Optical) Disk drive device or DVD (Digital V
ersatile disk) and the like.

FIG. 16 is a block diagram showing the configuration of the computer system shown in FIG. An internal memory 1202 such as a RAM and a hard disk drive unit 1204 are housed in a housing accommodating the computer main body 1102.
An external memory such as is further provided. The computer program for controlling the operation of the printer described above is recorded on a flexible disk FD, a CD-ROM, or the like, which is a recording medium, and read by the reading device 1110. Also, the computer program may be downloaded to the computer system 1000 via a communication line such as the Internet.

In the above description, the printer 1
Reference numeral 106 denotes a computer main body 1102 and a display device 110.
4, an example in which the computer system is configured by being connected to the input device 1108 and the reading device 1110 has been described, but the present invention is not limited to this. For example, the computer system may include the computer main body 1102 and the printer 1106, and the computer system may not include any of the display device 1104, the input device 1108, and the reading device 1110. Further, for example, the printer 1106 may be the computer main body 110.
2, the display device 1104, the input device 1108, and the reading device 1110 may have a part of their respective functions or mechanisms. As an example, the printer 1106 includes an image processing unit that performs image processing, a display unit that performs various displays, and
It may be configured to have a recording medium attaching / detaching portion for attaching / detaching a recording medium on which image data taken by a digital camera or the like is recorded.

Further, in the above-described embodiment, the computer program for controlling the printer may be loaded into the memory 65 of the control unit 60. And
The operation of the printer in the above-described embodiment may be achieved by the control unit 60 executing this computer program.

The computer system thus realized is superior to the conventional system as a whole system.

=== Other Embodiments === The printer and the like according to the present invention have been described above based on the embodiment. However, the above-described embodiment is for facilitating the understanding of the present invention. However, the present invention is not intended to be limitedly interpreted. It goes without saying that the present invention can be modified and improved without departing from the spirit thereof and that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the printing apparatus according to the present invention.

<Detection of Distance PG> According to the above embodiment, the distance PG from the nozzle of the head 21 to the paper is
Was detected by the gap sensor 54. However, the detection of the distance PG from the nozzle to the paper is not limited to the one using the gap sensor 54. For example, if information about the type of paper that is the printing target is obtained in advance, the thickness of the paper can be known from the type of paper, so the distance PG from the nozzle to the paper can be detected. In this case, it is preferable to store information about the relationship between the paper type and the distance PG as a table in the memory 65. Also,
In this case, the printer or the computer connected to the printer preferably has an input means for inputting the type of paper to be printed. For example, the user may input the type of paper to be printed by the user interface, and the computer or the printer may detect the distance PG from the type of paper based on the table stored in the memory. Further, if the printer has a plurality of trays for storing the paper to be printed, it is possible to obtain the information of the contained papers from the information on the trays. It is possible to detect the distance PG from the paper to the paper. In this case, it is preferable to store in the memory 65 the information regarding the paper stored in the tray.

<Regarding Detection of Carriage Speed> According to the above-described embodiment, the carriage speed is detected by the linear encoder 51. However, the detection of the speed of the carriage is not limited to the one using the linear encoder 51. For example, CPU 61 or D
The speed of the carriage may be detected based on the drive command given from the C unit 66 to the CR motor drive.

<Detection of Carriage Acceleration> According to the above-described embodiment, the carriage acceleration is detected by the linear encoder 51. However, the detection of the acceleration of the carriage is not limited to the one using the linear encoder 51. For example, CPU6
The speed of the carriage may be detected on the basis of the drive command given to the CR motor drive from the controller 1 or the DC unit 66.

<Regarding Detection of Ink Velocity Vi> According to the above-described embodiment, the ink velocity Vi is detected based on the amount of ejected ink. However, the detection of the ink velocity is not limited to this. For example,
Since the viscosity of the ink changes and the ink velocity Vi also changes according to the change of the environmental temperature, the ink velocity may be detected based on the temperature. In this case, it is preferable to store information about the relationship between the ink velocity Vi and the temperature in the memory 65 as a table. If the ejected ink amount differs depending on the print mode, the ink speed V is changed based on the print mode selected by the user through the interface.
i may be detected.

<Regarding Gap Sensor> According to the above-described embodiment, the gap sensor 54 includes one light emitting unit and two light emitting units.
It has two light receiving portions, and this configuration detects the distance PG from the nozzle to the paper S. However, the configuration of the gap sensor is not limited to this. For example, even with a sensor having two light emitting units and one light receiving unit, the distance PG from the nozzle to the paper S can be detected by switching the light emission from the two light emitting units. Further, according to the above-described embodiment, of the light emitted from the light emitting unit, the light specularly reflected by the paper S is detected by the light receiving unit, but the light diffused by the paper S may be detected. Also,
By other methods, the distance PG from the nozzle to the paper S
Needless to say, may be detected.

<Regarding the Nozzle> According to the above-described embodiment, since the nozzle is provided in the head 21 and the head 21 is provided in the carriage 41, the nozzle is provided integrally with the carriage 41. However, the configurations of the nozzles and the head 21 are not limited to this. For example, the nozzle or head may be a cartridge 48 (see FIG. 2).
It may be integrally provided with the carriage 41 and detachable from the carriage 41.

[0100]

According to the printing apparatus of the present invention, the timing of ink ejection is controlled based on a plurality of detected signals. Therefore, even if the detected speed includes an error,
The deviation of the ink landing position can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an overall configuration of an inkjet printer of this embodiment.

FIG. 2 is a schematic diagram of the vicinity of the carriage of the inkjet printer of the present embodiment.

FIG. 3 is an explanatory diagram around a carrying unit of the inkjet printer according to the present embodiment.

FIG. 4 is an explanatory diagram of a configuration of a linear encoder.

FIG. 5 is a timing chart showing a waveform of an output signal of a linear encoder.

FIG. 6 is an explanatory diagram of a configuration of a gap sensor.

FIG. 7 is an explanatory diagram showing that the distance PG is detected at a plurality of points along the scanning direction.

FIG. 8 is an explanatory diagram showing that the distance PG is detected at a plurality of points along the paper feed direction.

FIG. 9 is a diagram showing a change over time of a moving speed of a carriage.

FIG. 10 is an explanatory diagram of a trajectory of an ink droplet.

FIG. 11 is an explanatory diagram of ink ejection timing.

FIG. 12 is a waveform of an output signal of the encoder when the carriage is moving.

FIG. 13 is a waveform of an output signal of the encoder when the carriage is accelerating.

FIG. 14 is an explanatory diagram of a waveform of a reference signal when the carriage is accelerating.

FIG. 15 is an explanatory diagram showing an external configuration of a computer system.

FIG. 16 is a block diagram showing the configuration of a computer system.

[Explanation of Codes] 10 Paper Conveying Unit 11A Paper Feeding Insert 11B Paper Ejecting Port 12 Paper Feeding Motor 13 Paper Feeding Roller 14 Platen 15 Paper Feeding Motor (PF Motor) 16 Paper Feeding Motor Driver (PF Motor Driver) 17A Paper Feeding Roller 17B Paper discharge rollers 18A, 18B Free rollers 19A, 19B, 19C Gear 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 instrument group 51 Linear encoder 511 Linear scale 512 Detection unit 12A emitting diodes 512B collimator lens 512C detection processing unit 512D photodiode 512E signal processing circuit 512F comparator 52 rotary encoder 53 paper detection sensor 60 control unit 61 CPU 62 Timer 63 interface unit 64 ASIC 65 memory 66 DC controller 67 host computer

Claims (12)

[Claims] 1. In a printing apparatus for printing ink on a printing medium by intermittently ejecting ink from a moving ink ejecting unit, a moving speed of the ink ejecting unit is sequentially detected, and a plurality of the detected inks are detected. A printing apparatus, characterized in that the timing of intermittent ejection of the ink from the ink ejection unit is controlled based on the speed. 2. The printing apparatus according to claim 1, wherein an average speed is calculated based on the plurality of detected speeds, and an average speed is calculated based on the calculated average speed. A printing apparatus which controls the timing of intermittent ejection of the ink. 3. The printing apparatus according to claim 2, wherein the calculated average speed is slower than a reference speed, and the ink ejecting unit is moving at the reference speed. A printing apparatus which ejects the ink at a timing delayed with respect to the timing of ejecting the ink. 4. The printing apparatus according to claim 2, wherein the timing at which the ink is ejected is delayed as the calculated average speed is slower. 5. The printing apparatus according to claim 2, wherein a delay amount of ink ejection is calculated based on the calculated average speed, and the ink ejection unit ejects ink. A printing apparatus which ejects ink by delaying the delay amount from a signal serving as a timing reference. 6. The printing apparatus according to claim 1, wherein the acceleration of the ink ejection unit is calculated based on the plurality of detected speeds, and the acceleration is calculated based on the calculated acceleration. A printing apparatus, wherein the timing of intermittent ejection of the ink from the ink ejection unit is controlled. 7. The printing device according to claim 1, further comprising a memory, wherein the detected speed is stored in the memory. 8. The printing device according to claim 1, wherein the moving speed of the ink ejecting unit is detected by an encoder. 9. A printing device for intermittently ejecting ink from a moving ink ejecting section to print on a printing medium, wherein the moving speed of the ink ejecting section is sequentially detected using an encoder, The detected speed is stored in a memory, an average speed is calculated based on the plurality of detected speeds, and an acceleration of the ink ejection unit is calculated based on the plurality of detected speeds. Controlling the timing of intermittent ejection of the ink from the ink ejecting section based on the average velocity and the acceleration, and when the calculated average velocity is slower than a reference velocity, the ink ejection Compared with the timing of ink ejection when the unit is moving at the reference speed, the ink is ejected at a delayed timing, and the slower the calculated average speed is, the more Printing device timing for ejecting ink, characterized in that delay. 10. A printing method in which ink is intermittently ejected from a moving ink ejecting unit to print on a printing medium, a step of sequentially detecting a moving speed of the ink ejecting unit, and a plurality of the detections. Controlling the timing of intermittent ejection of the ink from the ink ejecting section based on the determined speed. 11. A function of causing a printing apparatus, which intermittently ejects ink from a moving ink ejection unit to print on a printing medium, to sequentially detect the moving speed of the ink ejection unit, and a plurality of the detection units. And a function of controlling the timing of intermittent ejection of the ink from the ink ejecting unit based on the speed thus performed. 12. A computer system comprising a computer main body and a printing device connectable to the computer main body, wherein the printing device intermittently ejects ink from a moving ink ejecting section, Printing is performed on the ink ejection unit, the moving speed of the ink ejecting unit is sequentially detected, and the timing of intermittent ejection of the ink from the ink ejecting unit is controlled based on the plurality of detected speeds. Characteristic computer system.