JP2003182179A - Printer and control method for actuator for carriage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer and a control method for an actuator for carriage in which occurrence of unevenness of print is retarded in the main scanning direction of a carriage. <P>SOLUTION: When the power switch 39 of a printer 1 is turned on, a CPU 27 performs full digit drive processing for running a carriage 3 idly without ejecting ink. During full digit drive processing, the CPU 27 calculates the moving speed of the carriage 3 at a plurality of positions in a section of constant speed range where the speed of the carriage 3 becomes constant. Upon the full digit drive processing, the CPU 27 performs a target speed correction processing for correcting the reference target speed refv<SB>0</SB>(refv<SB>1</SB>to refv<SB>3</SB>) of the carriage 3 and calculating a new corrected target speed refv<SB>x</SB>. When the carriage 3 performs scanning subsequently, the CPU 27 moves the carriage 3 at a target speed thereof set for each position P<SB>1</SB>, P<SB>2</SB>,..., P<SB>n</SB>with reference to a speed value table 40 stored in an RAM 30. <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 carriage actuator control method.

[0002]

2. Description of the Related Art Conventionally, there is an ink jet printer as a printing device. This type of printer is equipped with a carriage 81 shown in FIG. 9, and a recording head 82 is attached to the lower part of the carriage 81. A carriage motor (both not shown) is connected to the carriage 81 via a timing belt, and the carriage 81 reciprocates in the main scanning direction (direction of arrow M shown in FIG. 9) along the carriage shaft 83 using the motor as a drive source. To do. In addition, the carriage 81
A linear encoder (not shown) is provided in the carriage, and the position, speed, etc. of the carriage 81 are detected based on the detection signal from the encoder.

The speed state of the carriage 81 during the printing process is such that the carriage 81 first accelerates and then becomes a constant speed state. Then, in the constant speed state, ink is ejected from the recording head 82 at a predetermined timing, and the printing process is executed. The ink ejection timing is triggered by the detection signal from the linear encoder. in short,
Carriage 81 based on the detection signal from the linear encoder
Is detected, and ink ejection is started when the carriage 81 reaches a predetermined position. Then, after that, ink is ejected from the recording head 82 at regular time intervals.

A target speed is set for the carriage 81 as a speed value in the constant speed state. This target speed is a constant value, and thus the carriage 81 moves at a constant speed at the target speed. Therefore, even if the ink is ejected from the recording head 82 at a constant time interval, if the carriage 81 moves at a constant speed, the interval ΔW between the dots 85 on the recording paper 84 that can be printed is almost the same. It is the same, and dot unevenness should not occur in the axial direction of the carriage shaft 83 (that is, the main scanning direction of the carriage 81).

[0005]

However, since the mechanical load applied to the carriage 81 is not always constant when the carriage 81 moves along the carriage shaft 83, the carriage 81 moves around the carriage shaft 83 during movement.
It may shake in the direction of arrow N. In particular, when inexpensive parts are used for the carriage 81, the carriage shaft 83, etc., the characteristics become remarkable. If this aims to reduce the product cost of the printer,
Since it is indispensable to use inexpensive parts, this is a phenomenon that always occurs when inexpensive parts are used for the purpose of cost reduction.

Further, the carriage motor has a cogging component, and the cogging component causes a velocity fluctuation in the carriage 81 at a predetermined interval. Therefore, due to these factors, the velocity waveform of the carriage 81 pulsates as shown in FIG. 10, which causes a problem that the carriage 81 does not have a constant velocity in the constant velocity range P _{1 to} P _n . As a result, as shown in FIG. 9, the interval ΔW between the dots 85 on the recording paper 84 is reduced.
Does not have a constant interval, and dot unevenness (banding unevenness) occurs in the main scanning direction of the carriage 81, and there is a problem that the print image quality of the direction component deteriorates.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a printing apparatus and a carriage actuator control method capable of preventing uneven printing in the main scanning direction of a carriage. is there.

[0008]

In order to solve the above problems, according to the invention of claim 1, a carriage having a recording head, an actuator for driving the carriage, and a moving speed of the carriage are detected. While moving the carriage at the reference target speed by driving the speed detecting means and the actuator, at that time, the moving speed of the carriage is detected at a predetermined position by the speed detecting means, and the moving speed and the reference target speed are And a control unit that drives the actuator to move the carriage at the corrected target speed so that the moving speed of the carriage approaches the reference target speed. The main point is that.

According to the present invention, first, as a pre-stage of the reference target speed correction, the correction means moves the carriage at the reference target speed. Then, at that time, the moving speed of the carriage at the predetermined position is calculated by the speed detecting means,
The correction target speed is calculated by the correction means at each speed detection position based on the moving speed of the carriage and the reference target speed. After calculating the corrected target speed, the control means drives the actuator to move the carriage at the corrected target speed. Therefore, even if an external load is applied to the carriage to cause the speed fluctuation, the speed fluctuation is eliminated by moving the carriage at the corrected target speed. Therefore, the speed fluctuation does not occur in the carriage, and uneven printing in the main scanning direction of the carriage due to the speed fluctuation hardly occurs.

According to a second aspect of the present invention, in the first aspect of the present invention, the correction means executes the correction process of the reference target velocity in a constant velocity region in which the carriage has a constant velocity. Use as a summary.

According to the present invention, in addition to the operation of the invention described in claim 1, since the correction processing of the reference target speed is executed in a constant speed region in which the carriage has a constant speed, the movement speed of the carriage is fixed. Can be speeded up.

According to a third aspect of the invention, in the first or second aspect of the invention, the recording head is characterized in that ink is ejected at a constant time interval during a printing process.

According to this invention, in addition to the operation of the invention described in claim 1 or 2, since the ink is ejected at a constant time interval during the printing process, the carriage is used in this type of ink ejection method. Under the present circumstances, when the speed fluctuation occurs, uneven printing occurs due to the speed fluctuation. However, since the carriage is driven so as to move at the corrected target speed, fluctuations in the speed of the carriage are eliminated, and even if the ink ejection format is such that ink is ejected at regular time intervals, Printing unevenness in the main scanning direction is less likely to occur.

In the invention described in claim 4, claims 1 to 3 are provided.
In the invention described in any one of the above, the gist is that the correction means executes the correction process of the reference target speed when the power of the printing apparatus is turned on.

According to the present invention, in addition to the operation of the invention described in any one of claims 1 to 3, the correction processing of the reference target speed by the correction means is executed when the printing apparatus is powered on. Therefore, every time the power is turned on,
The correction target speed can be set.

According to the invention described in claim 5, claims 1 to 4 are provided.
In the invention described in any one of the above, the gist is that the correction means periodically executes the correction process of the reference target speed at predetermined intervals.

According to the present invention, in addition to the operation of the invention described in any one of claims 1 to 4, the correction processing of the reference target speed by the correction means is periodically executed at predetermined intervals. Therefore, for example, the correction target speed can be newly set even when the printing apparatus is continuously powered on.

According to the sixth aspect of the present invention, the first to fifth aspects are provided.
In the invention described in any one of the above, the printing device includes a plurality of print modes in which a moving speed of the carriage is different according to specifications of a printing process, and the correction unit includes:
The gist is that the correction process of the reference target speed is executed for each of the plurality of print modes.

According to the present invention, in addition to the operation of the invention described in any one of claims 1 to 5, even if a plurality of print modes exist, the correction target speed is set for each print mode. Can be done.

In the invention described in claim 7, claims 1 to 6 are provided.
In the invention according to any one of the items, a correction unit is provided that calculates a difference between the moving speed of the carriage and the reference target speed, and determines whether the difference exceeds a threshold value. The gist of the means is to stop the correction process of the reference target speed when the difference exceeds the threshold value based on the determination result of the determination means.

According to this invention, in addition to the operation of the invention described in any one of claims 1 to 6, the judging means calculates the difference between the moving speed of the carriage and the reference target speed, and the difference is calculated. It is determined whether the difference exceeds the threshold value. When the difference exceeds the threshold value, the correction means stops the correction process of the reference target speed. By the way, when the difference is too large, there is some trouble in the carriage, actuator, etc., and it is not preferable to perform the correction processing of the reference target speed in that state. Therefore,
When the difference exceeds the threshold value, the correction processing of the reference target speed is stopped, so that the correction target speed is not set in such a situation.

According to an eighth aspect of the present invention, there is provided a carriage actuator control method used in a printing apparatus including a carriage having a recording head and an actuator for driving the carriage, wherein the actuator is driven. While moving the carriage at the reference target speed, the speed detecting means at that time detects the moving speed of the carriage at a predetermined position, and the correcting means calculates the corrected target speed based on the moving speed and the reference target speed. However, the gist is that the control means drives the actuator to move the carriage at the corrected target speed so that the moving speed of the carriage approaches the reference target speed.

According to the present invention, the same effect as that of the first aspect can be obtained.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of a printing apparatus and a carriage motor control method embodying the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view showing the internal structure of the printer 1. A printer 1 as a printing device includes a printer body 2 inside, and a carriage 3 is provided in the printer body 2.
Is installed. The carriage 3 is attached to an endless timing belt 6 stretched by a drive pulley 4 and a driven pulley 5, and the timing belt 6 is driven by a carriage motor 7 as an actuator to be guided by a carriage shaft 8. Moves back and forth in the main scanning direction. A paper feed motor 9 is provided on the lower end side of the printer 1.
Is mounted, and the recording paper 10 is fed in the sub-scanning direction by driving the paper feed motor 9.

A recording head 11 is disposed on the lower surface of the carriage 3 facing the recording paper 10, and an ink cartridge 12 (in this example, a black cartridge for supplying black ink) to the recording head 11 is provided above the carriage 3. 2 for color
Types) are detachably attached. Recording head 1
A plurality of nozzles 13 (see FIG. 3) are formed in the nozzle 1, and ink is ejected from the nozzles 13 toward the recording paper 10 at a predetermined timing when the printing process is executed.

At the home position (right end in FIG. 1) of the carriage 3, a cap 14 capable of sealing the nozzle 13 of the recording head 11 is provided. This cap 1
Reference numeral 4 has a mechanical mechanism that seals the recording head 11 by pushing up the cap 14 by the carriage 3 itself when the carriage 3 is located at the home position (HP). That is, the recording head 11 is automatically capped when the carriage 3 is at the home position.

The cap 14 has a suction pump 1 for applying a negative pressure to the internal space of the cap 14 during the cleaning operation.
5 are connected via a pump tube 15a. The suction pump 15 is connected to a pump motor 16 (see FIG. 3) via a gear mechanism (not shown).
6 is the driving source. A wiping member 17 made of an elastic plate such as rubber is disposed between the print area of the recording head 11 and the home position, and the surface of the recording head 11 is covered by the wiping member 17 when the recording head 11 moves toward the print area. Wiping is processed.

The printer 1 is equipped with a linear encoder 18 for detecting the speed, moving direction, position, etc. of the carriage 3. The linear encoder 18 includes a semi-transparent resin tape 19 for detection (hereinafter, simply referred to as a tape) and an optical detection sensor 20 (see FIG. 3). 20 is attached to the back surface of the carriage 3. The detection sensor 20 moves along the tape 19 in synchronization with the carriage 3 when the carriage 3 reciprocates in the main scanning direction.

On the tape 19, a plurality of slits 21 are formed at a constant pitch along the moving direction of the carriage 3. As this pitch interval, the slit 21 is, for example, 1
It is formed every / 180 (inch) (= 2.54 / 180 (cm)). The detection sensor 20 detects the slit 21 on the tape 19 when moving together with the carriage 3,
Two types of detection signals (pulse signals) SG1 and SG2 shown in FIG.
Is output.

FIG. 2 is a waveform diagram of a pulse signal output from the detection sensor 20. When the carriage motor 7 is rotating in the normal direction, the detection sensor 20 outputs the pulse signals SG1 and SG2 with the phase of the pulse signal SG1 advanced by 90 degrees with respect to the pulse signal SG2, as shown in FIG. . On the other hand, when the carriage motor 7 is rotating in the reverse direction, the detection sensor 20 outputs the pulse signal SG1 as shown in FIG.
Pulse signal SG1, with a 90 degree phase delay with respect to 2
Output SG2. Since the cycle T of the pulse signal SG1 (SG2) is the time required to move the slit 21 by one interval, the carriage 3 can be measured by measuring the cycle T.
The speed V of is calculated.

When the pulse signal SG1 rises, the pulse signal SG2 becomes L level and H level when the carriage motor 7 rotates forward and backward, respectively. Therefore, the pulse signal SG2 of the pulse signal SG1 rises. The moving direction of the carriage 3 is detected by looking at the level state. Further, by counting the rising and falling edges of the pulse of the pulse signal SG1 (SG2), the carriage 3
The position from the home position of is detected. In addition, as for the number of counts, the carriage 3 is in the left direction (counter HP direction) in FIG.
It is incremented when it moves to the right direction (H
Decremented when moving in P direction.

FIG. 3 is an electrical block diagram of the printer 1. The printer 1 is connected to a host computer 23 via a cable 22. The printer 1 is the control device 24
The control device 24 drives various motors 7, 9, 16 and the recording head 11 to control the entire device of the printer 1. The paper feed motor 9 drives the transport roller 25 and the paper discharge roller 26, and the paper feed motor 9 drives the two rollers 25 and 26 to feed the recording paper 10.

The control device 24 includes a CPU 27, an ASIC 28, and a PR which constitute speed detecting means, correcting means and control means.
An OM 29, a RAM 30, an EEPROM 31, and an interface (I / F) 32 are provided. CPU27 is PR
RAM based on the control program stored in OM29
The entire device of the printer 1 is controlled with 30 as a work area. The CPU 27 exchanges various data with the host computer 23 via the I / F 32 and the ASIC 28. Further, the CPU 27 uses the I / F 32 and ASI.
Based on the print data input from the host computer 23 via C28, the ASIC 28 is controlled to execute print processing and the like. The CPU 27 and the linear encoder 18 constitute a speed detecting means.

The controller 24 is the pump motor driver 3
3, a paper feed motor driver 34, a carriage motor driver 35, and a head driver 36. ASIC
28 controls the drivers 33 to 36 based on a control signal from the CPU 27 in order to execute various processes such as a printing process and a maintenance process. These drivers 33 to 36 output drive signals corresponding to the control signals sent from the ASIC 28 to the respective motors 7, 9, 16 and the piezo 37 built in the recording head 11 to drive the various motors 7, 9, 16 and the piezo 37. To drive.

Further, the CPU 27 uses the linear encoder 18
Is connected via a signal line 38, and pulse signals SG1 and SG2 are input from the detection sensor 20.
Then, the CPU 27 calculates the moving speed V of the carriage 3 based on the cycle T of the pulse signal SG1 (SG2).
The CPU 27 detects the moving direction of the carriage 3 by comparing the level states of the pulse signals SG1 and SG2, and counts the rising and falling edges of the pulse signals SG1 and SG2 to detect the position of the carriage 3.

When print data is transmitted from the host computer 23 and print processing is executed, the CPU 27 sets the ink ejection start position for each pass based on the print data. Then, the CPU 27 starts the ink ejection when the position of the carriage 3 obtained from the count number of the pulse signals SG1 and SG2 of the detection sensor 20 reaches the ink ejection start position determined by the print data, and thereafter the ink is ejected at a constant time interval. Is discharged. A power switch 39 is connected to the CPU 27, and the CPU 27 uses the power switch 39.
When is pressed and an ON signal is input, the printer 1 is started.

FIG. 4 is a waveform diagram showing the relationship between the position of the carriage 3 and the moving speed V, and FIG. 5 is a table showing the speed measurement position and the carriage speed at that position. PR of printer 1
The reference target speed refv ₀ is stored in the OM 29 as a moving speed when the carriage 3 is driven. The reference target speed refv ₀ is a value for determining the moving speed of the carriage 3 and is set as a constant value. As a result, before performing the target speed correction process described later, the CP
Since U27 moves the carriage 3 at the reference target speed refv ₀ , as a result, the speed waveform periodically pulsates due to the mechanical load of the carriage 3 and the cogging component of the carriage motor 7 as shown in FIG. It will be in a state.

A plurality of types of print modes are set in the printer 1, and a speed mode is set for each print mode as a speed value for moving the carriage 3. By the way, in this example, three print modes are set,
Reference target speed REFV when the printing mode A as the speed mode of the reference target speed REFV ₀ as shown in FIG. 5 _1, the reference target speed REFV ₂ when the printing mode B, the carriage 3 at the reference target speed REFV ₃ when the printing mode C Moves. It should be noted that these reference target velocities refv _{1 to} refv ₃ are constant values set for each print mode.

Now, when the power switch 39 of the printer 1 is turned on, the CPU 27 carries out the full-digit drive processing in which the carriage 3 runs idle in a state where ink is not ejected in all print modes (in this example, three patterns A to C). ). In this full digit drive processing, the carriage 3 is scanned in the entire drive range R (see FIG. 4) from the movement start position to the movement end position, and if there are three print patterns as in this example, the carriage 3 is moved to three positions. It will be shuttled. In the full digit drive process, the carriage 3 is driven in each of the print modes A to C while keeping the reference target speeds refv _{1 to} refv ₃ constant.

During execution of the full digit drive process, the CPU 27 calculates the moving speed V of the carriage 3 at a plurality of positions in the constant speed range P _{1 to} P _n (see FIG. 4) where the carriage 3 has a constant speed. . As the plurality of positions, the CPU 27
Is a pulse signal SG1 (SG
The moving speed V is calculated each time the pulse of 2) is detected. That is, the pulse detection position P _1, P _2, ..., when the P _n, the carriage 3 is located P _1, P _2, ..., the moving velocity V is calculated when a P _n. Then, the CPU 27 executes the calculation of the moving speed V for each of the print modes A to C.

Therefore, when the power switch 39 of the printer 1 is turned on, the CPU 27 first executes the full digit drive processing in the print mode A, and the moving speed V of the carriage 3 at this time is as shown in FIG. , P ₁ , P ₂ , ..., P _n
Current speed V ₁₁ at each position, V _{1 2,} ..., and calculates the V _1n.
Subsequently, the CPU 27 similarly causes the full-digit drive processing to be executed in the print modes B and C, and as shown in FIGS. 5B and 5C, the current speed at each position of P ₁ , P ₂ , ..., P _n. V ₂₁ , V ₂₂ ,
, V _2n , V ₃₁ , V ₃₂ , ..., V _3n are calculated.

After the full-digit drive processing is executed, the CPU 27 corrects the reference target speed refv ₀ (refv _{1 to} refv ₃ ) of the carriage 3 and executes the target speed correction processing for newly calculating the corrected target speed refv _x. . This corrected target speed refv _x is expressed _by the following equation (1)
Is calculated for each position of P ₁ , P ₂ , ..., P _n .

Revf _x = 100refv ₀ / (100 + X _i ) ... (1) where X _i (i = 1, 2, ..., N) is the position P _i calculated by the full digit drive process as shown in FIG. Is a difference between the moving speed V of the carriage 3 and the reference target speed refv ₀ . Then, the CPU 27 executes the correction of the reference target speed refv ₀ , that is, the calculation of the corrected target speed refv _x in all the print modes, and in this example, the three print modes A to C
The target speed correction process is executed with.

As described above, the CPU 27 first executes the target speed correction process in the print mode A, and the correction target speed refv _{x at} this time is P ₁ , P ₂ , ..., As shown in FIG. 6A.
Correction target speeds refv ₁₁ , refv ₁₂ , ..., refv at each position of P _n
Calculate _1n . Subsequently, the CPU 27 similarly executes the target speed correction processing in the print modes B and C, and as shown in FIG.
As shown in (c), the correction target speeds refv ₂₁ , refv ₂₂ , ..., refv _2n , refv ₃₁ , ref at each position of P ₁ , P ₂ , ..., P _n.
Calculate v ₃₂ , ..., refv _3n respectively. And FIG.
The calculation results shown in (a) to (c) are stored in the RAM 30 as the speed value table 40.

When the carriage 3 is subsequently scanned, the CPU 27 refers to the speed value table 40 stored in the RAM 30 and refers to the corrected target speed corresponding to each position of P ₁ , P ₂ , ..., P _n. Move the carriage 3 with refv _x . Therefore, the speed fluctuation of the carriage 3 due to the mechanical load of the carriage 3 and the cogging component of the carriage motor 7 is suppressed, and the moving speed v of the carriage 3 is constant speed range P ₁ to It becomes almost constant at P _n so as to take the reference target speed refv ₀ . Accordingly, when the printing process is performed, the ink interval ΔW (see FIG. 9) becomes substantially constant, dot unevenness in the scanning direction hardly occurs, and deterioration of print image quality can be prevented.

Therefore, the following effects can be obtained in this embodiment. (1) Full-digit drive processing is executed when the power switch 39 is turned on, and target speed correction processing is performed based on pulse signals SG1 and SG2 output from the detection sensor 20 of the linear encoder 18 to detect pulse detection positions P ₁ and P 2. Correct the reference target speed refv ₀ with ₂ , ..., P _n . Then, the corrected target speed ref
v _x a is stored as a speed value table 40 in RAM 30, the carriage 3 at a corrected target speed REFV _x during subsequent printing process which is stored in the velocity value table 40 is driven. Therefore, the moving speed V of the carriage 3 is equal to the reference target speed.
It becomes almost constant as refv ₀ is taken, and the ink interval ΔW when printing is performed becomes almost constant, and it is possible to prevent dot unevenness in the scanning direction from occurring.

(2) In the printer 1 of this example, ink is ejected.
With a structure in which timing is sequentially discharged at fixed time intervals
It In the case of such a configuration, the constant speed range of the carriage 3 is
Surround P ₁~ P_nIf speed fluctuations occur in the
Ink unevenness occurs in the main scanning direction of the carriage 3.
U However, the target speed correction process is executed to execute the carriage 3
Ink is ejected at regular time intervals because
Main run on recording paper 10
The dot shift in the scanning direction can be suppressed to a low level.

(3) Since the full digit drive processing and the target speed correction processing are executed when the power switch 39 is turned on, the correction processing of the reference target speed refv ₀ can be executed when the power is turned on. In addition, since the correction process is executed every time the power switch 39 is turned on, a suitable correction target speed refv _x can be set each time.

(4) Although a plurality of print modes are set in the printer 1, the target speed correction process is executed for each of these print modes, so that a plurality of print modes can be handled.

(5) The carriage motor 7 that drives the carriage 3 has a cogging component as a motor characteristic under the present circumstances. Even if the cogging component is generated in the carriage motor 7 as described above, the speed fluctuation of the carriage 3 is caused. Can be hard to occur.

(Second Embodiment) Next, a second embodiment will be described with reference to FIG.
And FIG. 8 will be described. This embodiment is different from the first embodiment in that the initial value table is stored in the PROM 29 in advance, and the other parts are the same. Therefore, the same portions are denoted by the same reference numerals, detailed description thereof will be omitted, and only different portions will be described.

FIG. 7 is an electrical block diagram of the printer 1.
8A to 8C are initial value tables for each print mode. As shown in FIG. 7, the initial value table 41 is stored in the PROM 29 in advance when the program is installed. The correction target speed refv _x is stored in the initial value table 41.
Are stored according to the difference X _j (j = a, b, ..., N) between the current speed V of the carriage 3 and the reference target speed refv ₀ . The corrected target speed refv _x stored in the initial value table 41 is calculated based on the equation (1) described in the first embodiment.

The corrected target speed refv _x is stored for each print mode. There are three patterns of printing modes A~C in this example, X _a as shown in FIG. 8 (a) when the printing mode A, X _b, ..., each of X _n (where, X _a <X _b ...) Corrected target speed refv _x for each difference as corrected target speed ref
v _1a , refv _1b , ..., Refv _1n are stored. Further, in the print modes B and C, as shown in FIGS. 8B and 8C, the correction target speed ref is set for each difference of X _a , X _b , ..., X _n.
v _2a , refv _2b , ..., refv _2n , refv _3a , refv _3b , ..., refv
_3n are stored respectively.

When the power switch 39 of the printer 1 is turned on, the CPU 27 executes the full digit drive processing in all print modes (generally, three patterns A to C). In this full digit drive processing, the carriage 3 is scanned in the entire drive range R (see FIG. 4) from the movement start position to the movement end position,
When there are three print patterns as in this example, the carriage 3 reciprocates three times. In the full digit drive process, the carriage 3 is driven in each of the print modes A to C while keeping the reference target speeds refv _{1 to} refv ₃ constant.

During execution of this full digit drive processing, the CPU 27
Calculates the moving speed V of the carriage 3 by using the pulse of the pulse signal SG1 (SG2) from the detection sensor 20 as a trigger,
The difference X _i between the reference target speed refv ₀ and the moving speed V according to the print mode at that time is calculated. And the CPU 27
Is an initial value table 4 of the PROM 29 based on the value of the difference X _i.
With reference to 1, the corrected target speed refv _x corresponding to the value of the difference X _i , X _j , is read. Then, the CPU 27 stores the corrected target speed refv _x in the RAM 30 in association with the pulse detection position P _i .

Subsequently, the CPU 27 causes the reference target speed re
fv₀To correct the pulse signal SG1 (SG2) pulse
It is executed every time a line is detected, and it is shown in FIGS.
The velocity value table 40 is created in the RAM 30. this
When scanning the carriage 3 thereafter, the CPU 27
Referring to the speed value table 40 stored in M30, P
₁, P₂,…, P_nCorrected target speed refv according to each position of_xso
The carriage 3 is moved. Therefore, as compared with the first embodiment
Similarly, the moving speed v of the carriage 3 is a constant speed range P. ₁~ P_nTo
Reference target speed refv₀Is almost constant as
Prints because dot unevenness in the scanning direction is less likely to occur.
Deterioration of image quality can be prevented.

Therefore, in the second embodiment as well, the first
In addition to the same effects as (1) to (5) of the embodiment, the following effects can be obtained. (6) The initial value table 41 is stored in advance in the PROM 29, and the moving speed V of the carriage 3 and the reference target speed refv
_The corrected target speed refv _x corresponding to the difference X _{j from 0} is read from the initial value table 41, and the speed value table 40 is created in the RAM 30. Therefore, since complicated calculation processing is not required when creating the speed value table 40, the processing speed when creating the speed value table 40 during the target speed correction processing can be increased.

The embodiment is not limited to the above, but may be modified into the following modes. (Modification 1) In each of the above-described embodiments, the target speed correction process (including the full digit drive process) is not limited to being executed when the power switch 39 is turned on. For example, these processes may be executed at regular intervals in a predetermined cycle after the power switch 39 is turned on. in this case,
Even if the power switch 39 of the printer 1 remains turned on for a long period of time, the target speed correction process can be executed.

(Modification 2) In each of the above-described embodiments, the target speed correction process (including the full digit drive process) is not limited to when the power switch 39 is turned on or every predetermined cycle interval. For example, in addition to these, the configuration may be executed after a maintenance operation such as cleaning.

(Modification 3) In each of the above embodiments, the correction of the reference target speed refv ₀ is not limited to be performed every time the pulse signal SG1 (SG2) output from the detection sensor 20 of the linear encoder 18 is detected. . For example, the corrected target speed refv _x may be calculated every other pulse signal detection position or every other pulse signal detection position.

(Modification 4) In each of the above-described embodiments, the carriage 3 is not limited to move the entire area between the home position and the end of the full-digit drive processing. For example, when the speed fluctuation of the carriage 3 has a constant cycle as its fluctuation characteristic, the carriage 3 may be moved by one cycle during the full digit drive processing.

(Modification 5) In each of the above embodiments, a threshold value is set for the value of the difference X _i between the moving speed V of the carriage 3 and the reference target speed refv _0, and the CPU 27 (judging means) uses this difference. It is determined whether the value of X _i exceeds the threshold value. When the difference X _i exceeds the threshold value, it may be determined that some abnormality has occurred in the carriage 3 or the carriage motor 7, and the target speed correction process may be stopped or interrupted.

(Modification 6) In each of the above-described embodiments, when the target speed correction process (including the full digit drive process) is corrected once and then corrected again, a new correction is performed. The previous correction target speed refv _x is stored in the RAM 30. Then, the CPU 27 calculates an error between the newly calculated corrected target speed refv _x and the immediately preceding corrected target speed refv _x, and when the error is extremely large, performs the target speed correction process again, Suitable correction target speed re
You may use fv _x . In this case, for example, if a temporary load is applied to the carriage 3 during execution of the full digit drive process, an unsuitable correction target speed will be set.
By performing the processing as described above, the preferable corrected target speed refv _x
Can be set.

(Modification 7) In each of the above-described embodiments, the full-digit drive processing is not limited to the operation in the idling state so as not to eject ink. That is, the full digit drive process may be executed while the print process is performed and ink is ejected.

(Modification 8) In each of the above embodiments, the full digit drive processing is not limited to the configuration in which the full digit drive processing is always performed before the target speed correction processing is performed, and the full digit drive processing may be omitted. For example, as in the second embodiment, the PROM 29
In the configuration in which the initial value table 41 is stored in the table 3, the correction target speed refv _x may be sequentially read from the initial value table 41 during the printing process, and the carriage 3 may be scanned based on the read. Even in this case, the speed fluctuation of the carriage 3 can be suppressed, and it is not necessary to perform the full-digit drive processing to idle the carriage 3.

(Modification 9) In each of the above-described embodiments, the target speed correction process (including the full digit drive process) is performed in the constant speed range P.
_The execution is not limited to the section of _{1 to} P _n , but may be executed in the acceleration region of the carriage 3, for example.

(Modification 10) In each of the above embodiments,
The actuator that moves the carriage 3 is not limited to the motor, and other drive sources such as a cylinder may be used.
The printing apparatus is not limited to the configuration of the printer 1, and the product model and internal structure thereof are not particularly limited as long as they are ink jet type. Further, the printing apparatus is not limited to the inkjet type, and the model thereof is not particularly limited as long as it has the carriage 3 that ejects ink during the printing process.

The technical ideas that can be understood from the above-described embodiment and other examples will be described below along with their effects. (1) The storage means (29) according to any one of claims 1 to 7, wherein a corrected target speed corresponding to a difference between a moving speed detected by the speed detecting means and a reference target speed of the carriage is stored. The correcting means drives the actuator to move the carriage at a reference target speed, and at the same time, the speed detecting means detects the moving speed of the carriage at a predetermined position and corrects it by referring to the storage means. Set the target speed. In this case, since the correction target speed is calculated with reference to the storage means, the process for obtaining the correction target speed is simple.

(2) In claims 1 to 7 and the technical idea (1), a position detecting means (18, 27) for detecting the position of the carriage is provided, and the correcting means detects the position detected by the position detecting means. Based on the above, the moving speed is detected at the absolute position on the moving path of the carriage. In this case, since the moving speed is detected at the absolute position of the carriage, the corrected target speed can be calculated as a preferable value as compared with the case where the speed is detected at a predetermined time interval.

(3) In claims 1 to 7 and the technical ideas (1) and (2), when a plurality of corrections of the reference target speed are performed by the correction means, the correction target speeds of the previous time and this time are An error determination means (27) for calculating an error and determining whether or not the error exceeds a threshold value, and based on the determination result of the error determination means, a correction target speed that is the most suitable of the correction target speeds of the previous time and this time is corrected. And a setting means (27) for setting the speed. In this case, even if some temporary trouble occurs during the correction of the reference target speed by the correction means, the correction target speed at the time of the trouble is not set as the correction value.

(4) In claim 8, the correction means executes the correction processing of the reference target speed in a constant speed region in which the carriage has a constant speed. In this case, the same effect as in claim 2 is obtained.

(5) In claim 8 and the technical idea (4), the recording head ejects ink at a constant time interval during a printing process. In this case, the same effect as that of claim 3 is obtained.

(6) Claim 8, the technical idea (4),
In (5), the correction unit executes the correction process of the reference target speed when the printing apparatus is powered on. In this case, the same effect as in claim 4 is obtained.

(7) Claim 8, the technical idea (4) to
In (6), the correction means periodically executes the correction processing of the reference target speed at predetermined intervals. In this case, the same effect as in claim 5 is obtained.

(8) Claim 8, the technical idea (4) to
In (7), the printing apparatus includes a plurality of print modes in which the moving speed of the carriage is different according to the specifications of the print processing, and the correction unit performs the correction processing of the reference target speed in each of the plurality of print modes. Execute for each mode. In this case, the same effect as that of claim 6 is obtained.

(9) Claim 8, the technical idea (4) to
In (8), there is provided a judging means for calculating a difference between the moving speed of the carriage and the reference target speed, and judging whether or not the difference exceeds a threshold value, and the correcting means judges by the judging means. If the difference exceeds the threshold value based on the result, the correction process of the reference target speed is stopped. In this case, the same effect as that of claim 7 is obtained.

(10) Claim 8, the technical idea (4)
In (9), at least one of the technical ideas (1) to (3) is used as a constituent element. In this case, the effect according to each technical idea is acquired.

[0079]

As described in detail above, according to the present invention, it is possible to prevent uneven printing in the scanning direction of the carriage.

[Brief description of drawings]

FIG. 1 is a perspective view showing an internal configuration of a printer according to a first embodiment.

2A and 2B are waveform diagrams of a pulse signal output from a detection sensor of a linear encoder, in which FIG. 2A is a forward rotation of the carriage motor, and FIG.

FIG. 3 is an electrical configuration diagram of the printer.

FIG. 4 is a waveform chart showing the relationship between the position of the carriage and the moving speed.

FIG. 5 is a table showing speed measurement positions and carriage speeds at the positions.

6A to 6C are speed value tables for each print mode.

FIG. 7 is an electrical configuration diagram of a printer according to a second embodiment.

FIG. 8A to FIG. 8C are initial value tables for each print mode.

FIG. 9 is a schematic explanatory diagram showing a conventional ink ejection state.

FIG. 10 is a waveform chart showing the relationship between the position of the carriage and the moving speed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Printer 3 as a printing device ... Carriage 7 ... Carriage motor 11 as an actuator ... Recording head 18 ... Linear encoder 27 that constitutes speed detection means ... CPU that constitutes speed detection means, correction means, control means and determination means 39 … Power switch (power supply) refv ₀ … Reference target speed refv _x … Corrected target speed X _i … Difference V… Moving speed

Claims (8)

[Claims] 1. A carriage having a recording head, an actuator for driving the carriage, a speed detecting unit for detecting a moving speed of the carriage, and a driving unit for driving the actuator to move the carriage at a reference target speed. At that time, the moving speed of the carriage is detected at a predetermined position by the speed detecting means, and a correcting means for calculating a correction target speed based on the moving speed and a reference target speed; And a control unit that drives the actuator to move the carriage at the corrected target speed so as to approach the target speed. 2. The printing apparatus according to claim 1, wherein the correction unit executes the correction processing of the reference target speed in a constant speed region in which the carriage has a constant speed. 3. The printing apparatus according to claim 1, wherein the recording head ejects ink at regular time intervals during printing processing. 4. The correcting unit executes the correction process of the reference target speed when the printing apparatus is powered on. Printing device. 5. The printing apparatus according to claim 1, wherein the correction unit periodically executes the correction processing of the reference target speed at predetermined intervals. 6. The printing apparatus includes a plurality of print modes in which the moving speed of the carriage is different according to the specifications of the print processing, and the correction unit includes a plurality of correction processing of the reference target speed. 6. The printing apparatus according to claim 1, wherein the printing apparatus is executed for each mode. 7. A judgment means for calculating a difference between a movement speed of the carriage and the reference target speed, and judging whether or not the difference exceeds a threshold value, wherein the correction means comprises: The printing apparatus according to claim 1, wherein when the difference exceeds a threshold value based on the determination result, the correction process of the reference target speed is stopped. 8. A method for controlling a carriage actuator used in a printing apparatus including a carriage having a recording head and an actuator for driving the carriage, the actuator being driven to drive the carriage at a reference target speed. While moving, the moving speed of the carriage is detected at a predetermined position by the speed detecting means at that time,
The correction means calculates a correction target speed based on the moving speed and the reference target speed, and the control means drives the actuator to move the carriage so that the moving speed of the carriage approaches the reference target speed. A method for controlling a carriage actuator, which is characterized by moving at a corrected target speed.