JP2003276269A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer which prevents a deterioration in printing quality at an end section of a paper by suppressing the overshoot or undershoot of a speed of a carriage having mounted thereon a print head when the carriage is moved from an accelerating region to a constant speed region and reduces the size of the printer by reducing the accelerating region. <P>SOLUTION: In this inkjet printer, the carriage having mounted thereon the print head is moved in a direction perpendicular to a paper feed direction. An LUT storing a speed control profile for realizing smooth transition of the speed when the carriage is moved from the accelerating region to the constant speed region is provided for speed control along the LUT. <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 an ink jet printer which prints by scanning a carriage equipped with a print head in a direction intersecting a paper transport direction, and more particularly to a technique for improving print quality at an edge of a paper.

[0002]

2. Description of the Related Art Inkjet printers for large-format paper that print on large-format paper such as A0 size paper and wide roll paper, use a carriage equipped with a comparatively heavy print head having a large number of ink nozzles to feed the paper. By scanning in the direction orthogonal to the direction, so-called one band printing is performed, and this band printing is repeated while intermittently conveying the paper, thereby printing one sheet of paper. Carriage scanning during band printing requires accelerating scanning to reach a constant maximum speed in the print area and decelerating scanning until the carriage is stopped at the end of the carriage.

In general, such speed control is called trapezoidal control, and as shown in FIG. 8, the speed is accelerated by ta time to reach the maximum speed, and the speed is maintained during tb time when printing is performed. , After the printing is completed, the speed is controlled to stop before the carriage end.

[0004]

However, even if the carriage is accelerated by uniform acceleration, the acceleration is stopped when the target speed is reached, and the speed is switched to the uniform speed control, the uniform speed is not reached immediately. There has been a problem that such overshooting or undershooting of the speed occurs and the printing quality at the edge of the paper is impaired. In general, it is expected that the acceleration area and deceleration area that do not contribute to printing will be made as small as possible in view of downsizing of the apparatus, but there is a drawback that the reduction of the area further deteriorates the print quality at the end of the carriage. .

It is an object of the present invention to provide an ink jet printer capable of performing carriage speed control capable of obtaining stable print quality from the edge of a sheet.

[0006]

In order to achieve the above object, the present invention provides an ink jet printer for performing printing by scanning a carriage equipped with a print head in a direction intersecting a paper transport direction. A lookup table (hereinafter abbreviated as LUT) that receives the information about the elapsed time from the start of the carriage and outputs the driving torque information of the motor that drives the carriage is used, and the acceleration before the constant velocity is applied to the LUT. Was gradually reduced, and a speed control profile that was set up to achieve uniform acceleration while smoothly performing speed transition was stored.

In the conventional speed control, the CP is the main control body.
I was using U. In other words, while monitoring the speed up to the constant velocity region and speed, if a delay occurs compared to the expected speed, increase the drive torque to increase the acceleration, and if it is faster than the expected speed, decrease the drive torque. It was controlled by setting and reducing the acceleration so that it would be a constant acceleration. In the conventional method, since the target speed that changes sequentially is accelerated by uniform acceleration, the relationship between speed and time can be expressed by a linear expression, and it is possible to sufficiently follow up even if the CPU operates while sequentially calculating the target speed. there were.

However, the variable acceleration control for making a smooth transition from the accelerating state to the constant velocity state requires at least about a 6th to 8th order calculation to successively calculate the target velocity, and the CPU calculates it. While it was difficult to realize.

[0009]

In order to detect the scale of the scale arranged along the scanning path in the vicinity of the scanning path of the carriage, a signal from a scale detecting sensor mounted on the carriage is input, and a signal from the sensor is input. A counter having a pulse generated at the rising edge of the clock as a clock input is provided, and a mechanism for clearing the counter at every constant time from the start of the carriage is provided, whereby the scanning speed of the carriage is counted by the counter. The scale interval is D
1. If the number of rising edges of the signal from the scale detection sensor within a fixed time is N1 and the fixed time interval for clearing the counter is t1, the carriage scanning speed is D1 * N1.
/ T1.

A counter having a pulse signal as a clock input for clearing the counter at every constant time after the carriage is started is provided, and the time from the start of the carriage is measured. Assuming that the count value of this counter is N2 and the fixed time interval is t1, the elapsed time from the start of the carriage is
It becomes t1 * N2.

On the other hand, the motion of the carriage is
It can be expressed by j * a + c * v = k (T−T0).
Here, j is the moment of inertia, a is the acceleration, c is the coefficient of dynamic friction, v is the speed, k is the proportional gain, T is the driving torque, and T is the driving torque.
0 is the initial drive torque. The initial drive torque refers to the torque required to start moving from a stationary state.
Solving this for T, T = (j * a + c * v) / k
It becomes + T0. j, c, k, and T0 are constants determined by the device, and from this equation, after the start-up and a fixed time have passed, the torque T at that timing is required because the carriage is operating at the acceleration a and the speed v. (J * a + c * v) /
Only k + T0 needs to be applied. In controlling the speed of the carriage, the expected speed transition is defined first, the torque transition for drawing the speed is calculated, and the torque is applied.

FIG. 10A shows an expected velocity transition diagram when the carriage velocity control is performed according to the present invention. Letting the elapsed time after startup be t, the acceleration in the section of time ta1 is a1
Then, in this section, since the acceleration is constant at the acceleration a1, the applied torque is v = a1 * t (where 0 ≦ t <
From ta1), T = (j * a1 + c * v) / k + T0 = (j * a1 + c
It can be expressed as * a1 * t) / k + T0. It is a linear expression of time t.

Next, in the section of time ta2, FIG.
As shown in FIG. 10B in which the portion A is enlarged, the acceleration is gradually reduced in order to smoothly transition the carriage speed to the constant velocity area after ta2. Acceleration a at this time,
The velocity v is a function of time t, and a (t) and v (t)
When expressed, the torque to be applied is T = (j * a (t) + c * v (t)) / k + T0 (where ta1 ≦ t <ta2). As described above, the expected velocity curve in this section is at least about the 6th to 8th order equations with respect to the time t, and therefore the acceleration a (t) is an equation obtained by differentiating the velocity v (t) with respect to t, that is, 5 From the following equation, the degree becomes about 7th degree.

In the constant velocity region, scanning is performed at the expected maximum speed, and in the deceleration region, deceleration is performed by the reverse acceleration when the acceleration is performed at time ta1. In the vicinity of the speed = 0 in the deceleration scanning, the speed itself is settled so that undershoot and overshoot do not occur, and since it is not the print area, it does not matter if there is any.

Further, in order to scan the carriage along the expected speed, it is necessary to apply a torque corresponding to the amount of deviation from the expected speed. This applies to all regions regardless of the constant acceleration region, variable acceleration region, constant velocity region, and deceleration region. Expected speed is ve, actual speed is v
r, the torque value to be applied at the expected speed is Te, and the speed gain constant is f, the corrected torque ΔT is ΔT =
Calculated as (ve-vr) * f. f is a positive value,
When the actual speed vr is larger than the expected speed ve, a negative correction torque obtained as a result of multiplying the torque value Te to be applied at the expected speed by the speed difference and a positive constant f is added, and finally the concerned speed vr is applied. The torque T applied at the timing is
T = Te + ΔT.

From the above, in the present invention, the carriage is shown in FIG.
In order to control at the expected speed shown in (a), the elapsed time t after the carriage is started and the actual traveling speed v of the carriage
Carriage speed that can obtain stable print quality from the edge of the paper by using the LUT that stores the torque value resulting from the variable control of the carriage acceleration and the correction control of the deviation amount from the expected speed for r. An inkjet printer capable of performing control is provided.

The elapsed time t after starting the carriage is
As described above, t = t1 * N2, but the constant time interval t1 is a fixed value, and the actual carriage speed v
r is vr = D1 * N1 / t1, but since the constant time interval t1 is also a fixed value and the scale scale interval D1 is also a fixed value, the elapsed time t after the carriage is started is input as the LUT. , The actual traveling speed vr of the carriage
Does not have to be, and the count value N of the counter that uses a counter that generates a pulse signal at fixed time intervals as a clock input
2 and the information of the number N1 of rising edges of the signal from the scale detection sensor within a fixed time can be substituted.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the overall structure of a printer according to an embodiment of the present invention, and FIG. 2 is a schematic front view showing the outline of the mechanical structure of the printer.

The ink jet printer 1 of this embodiment intermittently conveys A0 size paper and large-sized roll paper in a predetermined direction, and a print head 41 provided with a large number of nozzles in the paper conveyance direction. The ink is ejected from the nozzle while scanning in the orthogonal scanning direction (also referred to as the scanning direction) to print on a large-sized paper.

As a mechanism of the ink jet printer 1, as shown in FIG. 2, a print head 41 and a carriage 42A on which the print head 41 is mounted are moved along a rail 42B in a scanning direction (left and right direction in FIG. 2). A carriage mechanism 42, a paper transport mechanism 43 that transports the paper R in a predetermined direction (front-back direction in FIG. 2) by pressing the paper R against the platen 43a that is rotationally driven, and a display panel that displays operation content and messages An operation panel 44 for performing various settings by key input, a scale 46 provided along the rail 42B in the vicinity of the carriage rail 42B, and a scale 46 for forming ink discharge timing, and a scale 46 of the scale 46 mounted on the carriage 42A. For example, a scale sensor consisting of a photo coupler, etc. Sensor) comprising 45 and the like.

As a control system, as shown in FIG. 1, a CPU (Central Process) for performing overall control inside the printer.
sing unit) section 21, a ROM (Read O) that stores control programs and control data executed by the CPU section 21.
RAM as a fluctuation information storage means for providing a working memory space to the CPU section 21 and storing fluctuation information of the scanning speed of the carriage 42A and the like.
(Random Access Memory) 23, NVRAM that can hold data even when the power is cut off by a backup battery and stores custom information registered by the user
Each of the (non-volatile RAM) 24, the operation panel control unit 25 that performs key input from the operation panel 44 and the output control to the display unit of the operation panel 44, and the print head 41 at the timing based on the detection signal from the scale sensor 45. The print control unit 26 that outputs a signal for ejecting ink from the nozzles, and the carriage control unit 2 that controls the drive of the carriage mechanism 42.
7, a paper transport controller 28 that controls the drive of the paper transport mechanism 43, a host interface unit 29 that controls communication with the host computer, an image memory 30 in which print image data is written, and print data sent from the host computer. The image control unit 26 writes the image data in the image memory 30 or in accordance with the scanning of the print head 41.
An image memory reading / writing control unit 31 and the like for reading out to and from are provided. In FIG. 1, 20 is the CPU unit 21.
3 shows a control board including a printed board on which a RAM 23 and the like are mounted.

FIG. 3 shows the carriage control unit 2 of the printer 1.
7 is a block diagram of a carriage speed control circuit provided in FIG. The operation of each block in the carriage speed control circuit will be described below with reference to each time chart. The signal RST input to a plurality of blocks in the control circuit is a reset signal output from the CPU 66 and is output from the CPU 66 at the timing of activating the carriage. By the signal RST, the signal R
Each block inputting ST is initialized.

FIG. 5 is a time chart showing the movement of the pulse generator 61. The pulse generator 61 receives the detection signal SCL of the scale sensor 45, performs sampling with a clock signal CK having a constant cycle that is sufficiently shorter than the carriage traveling speed, and outputs a signal C at each rising edge of the signal SCL.
A signal PLS1 having a pulse width of one K clock is output.

FIG. 6 is a time chart showing the movement of the counter 62. The counter 62 receives the signal CK as a clock input and outputs the signal CK every time a count value of a certain amount is measured.
The signal PLS2 for one clock is output. 5 in FIG.
An example in which the signal PLS2 is output each time 00 is counted is shown.

FIG. 7 is a time chart showing the movements of the counter 63, the latch 64, the counter 65, the LUT 67, and the PWM block 68.

The counter 63 receives the signal PLS1 as a clock input and outputs a count value CNT1. Also the signal P
It is reset every time LS2 is input. That is, the signal PLS1 input at a fixed time measured by the counter 62
Is output by CNT1.

The resolution of the scale 46 is 720 LPI (li
ne per inch), one cycle of the detection signal SCL from the scale sensor 45 is 25.4 [mm] /
720 [LPI] = 35.277. ． ． [Μm]. Therefore, the carriage is 35.277. ． ． One pulse of the signal PLS1 is input to the counter 63 each time [μm] proceeds. Further, if the frequency of the signal CK is 1 MHz and the count cycle of the counter 62 is 500 as shown in FIG. 6, the speed of the carriage can be calculated from the count value CNT1 measured by the counter 63. Carriage speed = 35.277. ． ． [Μm] * CNT1 / 500 [μs] = 70.555. ． ． * CNT1 [mm / s] The count value CNT1 is latched by the latch 64 at the timing of the signal PLS2. Latched result is Latch 6
4 is output as a signal S1.

The counter 65 receives the signal PLS2 output by the counter 62 at regular intervals as a clock input, and outputs a count value CNT2. The counter 65 is reset by the signal RST output from the CPU 66 at the timing of starting the carriage. That is, the signal CK
When the frequency is 1 MHz and the count cycle of the counter 62 is 500 as shown in FIG. 6, the elapsed time after the carriage is started can be calculated from the count value CNT2 measured by the counter 65. Elapsed time after starting the carriage = 5
00 [μs] * CNT2 = 500 * CNT2 [μs] L
The UT 67 inputs the signal S1 output from the latch 64 and the signal CNT2 output from the counter 65, and determines the motor drive torque to be applied from the information of the elapsed time after the carriage startup and the carriage speed obtained from the signal input. It selects and outputs the signal TRQ. CNT2 multiplication value 500 in the elapsed time calculation after the carriage is started, and CNT1 multiplication value 70.55 in the carriage speed calculation
5. ． ． Is a fixed value, the count value CNT2 and the count value CNT1 are latched as the input information of the LUT 67.
Only the value S1 latched in 4 is sufficient.

The PWM block 68 receives the signal TRQ output from the LUT 67, and a motor driver (not shown) can receive torque information.
dulation) Waveform signal WAV is output. The PWM block 68 receives the signal CK having a constant cycle sufficiently shorter than the carriage traveling speed as a clock input, and generates the signal WAV. The PWM block 68 is reset by the signal RST output from the CPU 66 at the timing of starting the carriage.

The value 15 of CNT1 is latched by the latch 64 at the timing of PLS2 (a) of the signal PLS2 of FIG. 7, and the value of S1 becomes 15. At the same time, PLS2 (a)
At the timing of, the count value CNT2 of the counter 65 is 5
It becomes 1, and S1 = 15 and CNT2 = 51 are output to the LUT 67. The LUT 67 outputs TRQ = 20 as a result of inputting the values of S1 and CNT2. In the PWM block, the timing PLS2 of the next signal PLS2
The TRQ value 20 output from the LUT 67 in (b) is input, and the pulse width signal WAV corresponding to the torque value is output. In FIG. 7, the carriage speed (latch value S1 of the count value CNT1) gradually increases with the passage of time (increase of the count value CNT2) after the carriage is activated, and the motor drive torque value (TRQ) and the motor driver applied pulse width ( WAV) is increasing.

Next, a concrete example of the LUT 67 will be described.

Physically, a 512 Kbyte memory as shown in FIG. 14 is used, and the signal S1 from the latch 64 and the signal CNT2 from the counter 65 are connected to the address signal of the memory and output to the PWM block 68. Signal TRQ
Is connected to the data signal of the memory. In this example, the bit width of the signal S1 is 7 bits, the bit width of the signal CNT2 is 12 bits, and the bit width of the signal TRQ is 8 bits.
It is necessary to select an optimum bit width according to the frequency of K, the number of cycles counted by the counter 62, and the like. Figure 1
The respective bit widths shown in 4 are those which have been selected in accordance with the various conditions defined in the above embodiment.

Next, regarding the contents of the LUT 67, the acceleration of the carriage is 0.6 G, the constant velocity during printing is 800 mm.
An example of controlling by / s will be shown. L
The UT stores a series of velocity profiles for the acceleration region, the constant velocity region, and the deceleration region. Here, the smooth transition portion from the acceleration region to the constant velocity region, which is the point of the present invention, will be particularly described. .

First, the expected velocity locus is designed. Figure 11
(A) Speed control in the case of normal trapezoidal control (graph line:
va) and the speed control of the present invention (graph: vb) are shown. FIG. 11B shows an enlarged view of the transition portion from the acceleration region to the constant velocity region. The velocity v for the linearly accelerating portion is v [mm / s] = 0.6 * 9800 * CNT2
* 500 * 10 ^ (-6), v [mm /
s] = 800. Regarding the portion from 252 to 292 of CNT2 in the expected speed transition (graph: vb) of the present invention, CNT2 = 252 and CNT2 = 292.
Calculate and apply an approximate curve that smoothly connects the points. For example, the velocity v of the portion is v [mm / s] = 96250.3062601019−
2041.1500008003416 * CNT2 + 18.
42118767677462 * CNT2 ^ 2-0.09
060276564426248 * CNT2 ^ 3 + 0.0
002571611613767 * CNT2 ^ 4-3.
990826262515987 * 10 ^ (-7) * CN
T2 ^ 5 + 2.63412747120584 * 10 ^
It can be expressed by a 6th order equation (-10) * CNT2 ^ 6.

Next, the acceleration for controlling at the above speed is calculated. The acceleration a for the linearly accelerated portion is a [mm / s ^ 2] = 0.6 * 9800, and a [mm / s ^ 2] = 0 in the constant velocity region. CNT2 in the expected speed transition (graph: vb) of the present invention in FIG.
For the part from 252 to 292, the 6th order equation is differentiated with respect to CNT2, and a [mm / s ^ 2] = (− 2041.15008003
416 + 18.42118767677462 * 2 * CN
T2-0.0906027656426248 * 3 * C
NT2 ^ 2 + 0.0002571611613767 *
4 * CNT2 ^ 3-3.999082621655987
* 10 ^ (-7) * 5 * CNT2 ^ 4 + 2.63412
747120584 * 10 ^ (-10) * 6 * CNT2
5) / (500 * 10 ^ (-6)). Graph the transition of acceleration,
It is shown in FIG. FIG. 12B is an enlarged view of the transition portion from the acceleration region to the constant velocity region in FIG. 12A.

Next, the torque to be applied in order to scan at the expected speed transition is calculated. If the applied torque is T, T
= (J * a + c * v) / k + T0. a, v
Are the acceleration and velocity of the printer during scanning.
j, c, k and T0 are constants determined by the device, j is the moment of inertia, c is the coefficient of dynamic friction, k is the proportional gain, T0
Is the initial drive torque. In this embodiment, j = 4.7,
The torque T is calculated for a printer having the characteristics of c = 50.0, k = 1120, and T0 = 7.0. FIG. 13 shows the result of calculation by substituting the acceleration and velocity described above into the torque calculation formula. The LUT 67 has signals S1,
TR which is the above calculation result corresponding to the signal CNT2 input
The Q value is stored. FIG. 15 shows a part of the store result of the LUT 67.

The process of calculating a series of torque values for gradually applying along the expected speed transition has been described above. The carriage speed varies depending on the component parts, machine differences due to assembly variations, temperature / humidity, etc. Due to the environmental conditions of use and changes over time in the device itself, the scan may not be exactly as expected. Therefore, it is necessary to store data in the LUT 67 so that the correction torque in which the correction torque is added is applied according to the amount of deviation when the speed deviates from the expected speed. When the expected speed is ve, the actual speed is vr, the torque value to be applied at the expected speed is Te, and the speed gain constant is f, the corrected torque ΔT is ΔT = (ve-vr) * f
The torque T finally applied is calculated as
Store so that Te + ΔT. As described above, since the carriage speed can be replaced by the S1 value, if the expected S1 value is S1e and the actual S1 value is S1r,
It can be expressed as ΔT = (S1e−S1r) * f ′.
f'is a velocity gain based on the S1 value.

FIG. 16 shows an example of the LUT 67 of the portion storing the corrected torque with f '= 2.5. If the CNT2 value indicating the elapsed time after the carriage is started is 272 and the operation is as expected, it indicates the carriage speed S.
1 value is 11, and the torque value TR that should be set at this time
Although Q is 54, when S1 is 10 and is later than expected, the corrected torque T is: T = Te + (S1e−S1r) * f ′ = 54 + (11−10) * 2.5 = 56.5 Torque Since the value T is stored as an integer, the value after the decimal point is rounded down to T = 56, and a torque larger than the expected torque is applied. If S1 is 14 which is earlier than expected, T = Te + (S1e−S1r) * f ′ = 54 + (11−14) * 2.5 = 46.5. A torque smaller than the hourly torque is applied.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, although FIG. 4A shows a portion around the LUT 67 in FIG. 3, the capacity of the LUT is expanded as shown in FIG. 4B to provide a plurality of LUTs in one LUT memory for the CPU 6
It is also possible to input the signal SEL output from 6 to the upper address of the LUT 69 so that a plurality of LUTs in the LUT 69 can be selectively used. As a result, in the above-described embodiment, the specification can be used only with the acceleration of 0.6 G and the constant velocity of 800 mm / s, but it is possible to realize a plurality of scanning modes such as the acceleration of 0.2 G and the constant velocity of 400 mm / s. Further, even if the target acceleration and the constant velocity are the same at 0.6 G and 800 mm / s, it is possible to prepare a plurality of characteristics of the portion that transitions from the acceleration region to the constant velocity region. Even if the capacity of the LUT cannot be physically expanded, as shown in FIG. 4C, a plurality of LUTs are physically provided (LUT 70a, LUT 70b), and a selector 71 is provided at the output of the LUT and the selector 71 is provided. CPU66
The signal equivalent to the signal SEL output from the LUT is input, and the TRQ signal output from the plurality of LUTs is selectively output, so that the same function as in FIG. 4B can be realized.

Further, the portion of FIG. 4 (a) can be replaced as shown in FIG. 4 (d). In FIG. 4D, the signal S1 from the latch 64 and the signal CN from the counter 65 are
When T2 is input to the LUT 72, it is also input to the CPU 66, and the signal PLS2 output from the counter 62 to the CPU 66 is connected to the interrupt input of the CPU 66.
From the OM 22, data PRM summarizing the scan control parameters, the inertia moment j, the dynamic friction coefficient c, the proportional gain k, the initial drive torque T0, and the speed gain f are input. The means for solving the problem described that the CPU 66 can control the speed in the monotone acceleration portion, the constant speed portion, and the deceleration portion without using the LUT. Therefore, only the part that transitions from the acceleration region to the constant velocity region is the LUT
FIG. 4D shows an example in which 72 is used and the CPU 66 controls the other parts.

The CPU 66 uses the signal PLS2 as an interrupt, and inputs the signal CNT2 each time the signal PLS2 is input to recognize the position of the carriage. In the monotonic acceleration range, constant speed range, and deceleration range, the CPU 66 performs carriage speed control calculation processing by internal calculation based on the signal S1, the signal CNT2, and the scan control parameter signal PRM described above, and as a result, outputs the drive torque value to the signal TRQ2. . Further CPU66
Is a signal SE so that the signal TRQ2 output from the CPU 66 to the selector in the subsequent stage becomes valid as the signal TRQ.
Output L. On the other hand, in the portion where the position of the carriage needs to smoothly transition from the acceleration region to the constant velocity region, the signal S
1, a signal TR output from the LUT 72 based on the signal CNT2
The signal SEL is output so that Q1 becomes effective as the signal TRQ in the selector 71 in the subsequent stage. According to the method of FIG. 4D, the signal PLS2 is newly input to the CPU 66 as an interrupt, or the signal PRM which is a control parameter from the ROM 22 is newly input to the CPU 66, so that the circuit is slightly changed. Although complicated, the LUT 72 only needs to store the data of the minimum required portion, that is, the portion that smoothly transitions from the acceleration region to the constant velocity region, and the capacity of the LUT can be minimized. Of course, the scanning control parameter may be stored in the RAM 23 or the NVRAM 24 instead of the ROM 22 and input from that portion to be used.

[0043]

As described above, according to the present invention,
In an inkjet printer that performs printing by scanning a carriage equipped with a print head in a direction that intersects the paper transport direction, by smoothly transitioning a speed change using an LUT when scanning from an acceleration region to a constant velocity region,
Printing can be performed from the edge of the paper without impairing the printing quality. As a result, it is possible to reduce the size of the device without increasing the acceleration region.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a printer according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing an outline of a carriage traveling system of the printer.

FIG. 3 is a block diagram showing a carriage speed control circuit provided in a carriage control unit of the printer.

FIG. 4 is a diagram illustrating an embodiment around the LUT of FIG.

5 is a time chart explaining the operation of the pulse generator 61 of FIG.

FIG. 6 is a time chart explaining the operation of the counter 62 of FIG.

7 is a counter 63, a latch 64, a counter 6 of FIG.
5 is a time chart explaining the operations of the LUT 67, the PWM block 68,

FIG. 8 is a diagram illustrating trapezoidal control in carriage speed control.

FIG. 9 is a diagram illustrating overshoot and undershoot in carriage speed control.

FIG. 10 is a diagram illustrating a state in which the speed is smoothly changed from the acceleration range to the constant speed range according to the present invention.

FIG. 11 is a diagram illustrating a state in which a speed transition from an acceleration region to a constant velocity region is smoothly performed in the present embodiment.

FIG. 12 is a diagram illustrating an acceleration transition when a speed transition is smoothly made from the acceleration region to the constant velocity region in the present embodiment.

FIG. 13 is a diagram illustrating a change in torque value setting when a speed transition smoothly occurs from the acceleration region to the constant velocity region in the present embodiment.

FIG. 14 is an example of a physical realization form of the LUT 67 in the present embodiment.

FIG. 15 is a part of a content example of a specific implementation mode of the LUT 67 in the present embodiment.

FIG. 16 is a part of a portion different from FIG. 15 in the content example of the concrete realization form of the LUT 67 in the present embodiment.

[Explanation of symbols]

1 Inkjet printer 20 Control board 21 CPU section 22 ROM 23 RAM 24 NVRAM 25 Operation panel control section 26 Print control section 27 Carriage control section 28 Paper transport control section 29 Host I / F section 30 Image memory 31 Image memory writing / reading control section 41 print head 42 carriage mechanism 42A carriage 42B rail 43 paper transport mechanism 43A platen 44 operation panel 45 scale sensor 46 scale 61 pulse generator 62 counter 63 counter 64 latch 65 counter 66 CPU 67 LUT 68 PWM block 69 LUT 70a LUT1 70b LUT2 71 Selector 72 LUT R Paper SCL Scale scale detection signal CK Clock signal RST Reset signal PLS1 Scale scale detection signal SCL rising edge Impulsing pulse signal PLS2 Pulse signal CNT1 output from the counter 62 at a constant cycle Count value CNT2 indicating carriage traveling speed information Count value S1 indicating carriage traveling position information CNT1 Value latched at timing PLS2 TRQ LUT A signal SEL having a waveform of the motor drive torque value WAV TRQ value output from the selection signal TRQ1 for selecting a plurality of motor drive torque values. One of the torque value signals TRQ2 output from the plurality of motor drive torque value output means. One of the torque value signals output from the motor drive torque value output means PRM scan control parameter

Claims (5)

[Claims] 1. An inkjet printer that performs printing by scanning a carriage equipped with a print head in a direction intersecting a paper transport direction, and scanning speed detection for detecting an amount relating to a scanning speed of a carriage at a plurality of points in a carriage scanning region. Means, a scanning time detecting means for detecting an amount relating to an elapsed time from the start of the carriage, and a drive of a motor for driving the carriage based on the respective amounts detected by the scanning speed detecting means and the scanning time detecting means. An ink jet printer comprising means for outputting an amount relating to torque. 2. The scanning speed detecting means comprises a scale arranged near the scanning path of the carriage along the scanning path, and a scale detection sensor mounted on the carriage for detecting the scale of the scale. The ink jet printer according to claim 1, further comprising: a time measuring unit that measures a detection interval of a predetermined scale by the scale detection sensor. 3. A means for outputting a quantity related to a driving torque of a motor for driving a carriage based on the scanning speed detecting means and the scanning time detecting means, and a quantity related to the carriage scanning speed from the scanning speed detecting means and the quantity. 3. The lookup table according to claim 1, wherein the lookup time table is an input of an amount related to the elapsed time from the activation of the carriage from the scanning time detecting means and outputs an amount related to the driving torque of a motor for driving the carriage. Inkjet printer. 4. The look-up table stores at least a speed control profile configured to gradually reduce the acceleration before reaching a uniform speed and achieve uniform acceleration while smoothly performing a speed transition. The inkjet printer according to any one of claims 1 to 3, wherein the inkjet printer is provided. 5. The carriage drive motor torque amount added with a drive torque amount for correcting a difference between an expected speed and an actual speed of the carriage is stored in the look-up table. The inkjet printer according to claim 1.