JP2012131113A - Recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a recording head at a correct timing regardless of a change in relative moving speed in a configuration of converting the resolution of an encoder detecting relative moving positions of the recording head and a recording medium to a resolution desired for recording.SOLUTION: This recorder includes a measuring unit measuring a cycle of a position pulse signal of the encoder, a time managing unit loading a measured cycle value whenever the position pulse signal is detected and subtracting it as time goes by, a divided number storing unit storing a number m into which the cycle is divided, a divided number managing unit loading a set value concerned and subtracting one from the value whenever a divided pulse determining a recording head driving timing is output, and a divided pulse generating unit outputting the divided pulse when 1 or more numerals are left as the value. The divided pulse generating unit loads the values of the time managing unit and the divided number managing unit and thereafter does not output the next divided pulse until a time obtained by dividing the loaded value of the time managing unit by the value of the divided number managing unit elapses.

Description

  The present invention relates to a recording apparatus that performs recording while relatively moving a recording head and a recording medium. In particular, the present invention relates to a technique for generating a drive timing of a print head using a detection signal from a relative position detection means between the print head and a print medium, such as a linear encoder or a rotary encoder.

  In a conventional recording apparatus, an encoder such as a linear encoder or a rotary encoder is used, and the driving timing of the recording head is determined based on the timing of the position pulse signal output according to the relative movement between the recording head and the recording medium. . The drive cycle of the recording head is determined by the resolution (recording resolution) of the image to be recorded. When the recording resolution is equal to the resolution of the encoder, the recording head can be driven at the timing when the position pulse signal is output from the encoder.

  However, the recording resolution does not always match the encoder resolution. For example, as a linear encoder, an inexpensive one with a low resolution of about 300 lpi (line / inch; reference value) or 150 lpi is widely used, while a recording resolution is often 600 lpi or 1200 lpi or more.

  There is also a recording apparatus that can perform a recording operation by changing the recording resolution in accordance with the recording mode. Furthermore, for a recording head in which a large number of recording elements are arranged, recording may be performed while suppressing the instantaneous drive energy amount by performing time-division driving by dividing the large number of recording elements into several blocks. is there.

  As described above, conventionally, a drive timing of a high-resolution recording head is generated from a position pulse signal of a low-resolution encoder. In this method, it is common to measure the detection time interval of the position pulse signal from the encoder and determine the drive timing period by equally dividing the measured time interval by a predetermined number of divisions. . Such a method is effective when the period of the position pulse signal of the encoder is constant, that is, when the relative moving speed between the recording head and the recording medium is constant.

  However, if the period of the encoder position pulse signal is not constant, such as when the recording operation is performed even during the acceleration / deceleration period or when a minute error occurs in the encoder position detection, it is necessary to generate the drive timing appropriately. May occur. In this case, a problem arises when the cycle of the position pulse generated later is shorter than the cycle of the position pulse generated before, among the cycles of two adjacent position pulses detected successively. In such a case, the drive timing is generated at a shifted position by detecting the next position pulse while generating the drive timing based on the previously generated position pulse cycle. There was a problem that continued to be. Therefore, in Patent Document 1, a time difference between the period of the position pulse detected last time and the period of the position pulse detected this time is detected, and the detected time difference is detected with respect to the period of the position pulse detected this time. A method for correcting the above is disclosed.

  However, in the method described in Patent Document 1, since the drive timing is corrected in the position pulse period, the fluctuation of the period of the position pulse signal of the encoder, that is, the fluctuation of the relative moving speed between the recording head and the recording medium occurs. In some cases, the correction of the drive timing may be delayed.

JP 2000-033739 A

  The present invention has been made on the basis of recognition of the above-mentioned problems, and can freely convert the resolution of the encoder to a different resolution to drive the recording head, and is accurate even when there is a speed fluctuation. An object is to enable an image to be formed at a proper timing.

For this purpose, the present invention relates to the relative movement of the recording head and the recording medium, the resolution of the relative position detecting means for detecting the relative movement position is converted to a different resolution, and the driving of the recording head based on the converted resolution. A recording device for recording by performing
Measuring means for measuring a period of a relative position detection signal generated by the relative position detecting means in response to the relative movement;
Each time the relative position detection signal is generated, a time management unit that loads a value indicating the period measured by the measurement unit and subtracts it according to the passage of time;
Division number storage means for storing the number of divisions for time-dividing the period to perform the conversion;
Each time the relative position detection signal is generated, the division number stored in the division number storage means is loaded, and the time division signal used to determine the drive timing of the recording head is determined based on the loaded division number. A division number management means for subtracting one by one for each output;
A time division signal generating means for outputting the time division signal when the value remaining in the division number management means is 1 or more, wherein after the time division signal is outputted, the value indicated by the time management means is obtained; Time division signal generation means for not outputting the next time division signal until the time divided by the value indicated by the division number management means elapses;
It is provided with.

  According to the present invention, the recording head can be driven by freely converting the resolution of the encoder serving as the relative position detecting means to a different resolution, and an image can be obtained at an accurate timing even when there is a speed fluctuation. Can be formed.

1 is a perspective view showing an external appearance of an ink jet printer as a recording apparatus to which the present invention can be applied. FIG. 2 is a block diagram illustrating a configuration example of a control system of the ink jet printer of FIG. 1. 6 is a flowchart illustrating an example of a recording processing procedure of the inkjet printer according to the embodiment of the present invention. FIG. 3 is a block diagram illustrating an internal configuration example of a drive timing generation unit in FIG. 2. FIG. 5 is a block diagram illustrating a detailed configuration example of a divided pulse generation unit in FIG. 4. FIG. 5 is a timing chart showing an example of an encoder position pulse signal when the carriage is moving at a constant speed and each signal generated inside the drive timing generation unit shown in FIG. 4. 5 is a timing chart showing another example of an encoder position pulse signal when the carriage is moving at a constant speed and each signal generated inside the drive timing generation section shown in FIG. FIG. 8 is a timing chart showing an encoder position pulse signal when a speed variation occurs in the carriage and each signal generated inside the drive timing generation unit with respect to FIG. 7. FIG. 9 is a timing chart showing the operation in the conventional example with respect to FIG. It is a block diagram which shows the other structural example of a drive timing production | generation part.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiment and its constituent elements described in detail below are merely examples, and the present invention is not limited to them.

  FIG. 1 is a perspective view showing an appearance of an ink jet printer as a recording apparatus to which the present invention can be applied. The printer housing 100 includes a carriage 101 that can reciprocate relative to the recording medium 104. The carriage 101 is equipped with a recording head 102 and an optical sensor 103 for ejecting ink onto the recording medium 104. The linear scale 105 is provided so as to extend in the moving direction of the carriage 101, and slits are formed at predetermined intervals. The optical sensor 103 reads the slit of the linear scale 105 according to the movement of the carriage 101 and outputs a position pulse signal indicating the relative movement position. These optical sensor 103 and linear scale 105 constitute relative position detecting means in the form of an encoder (linear encoder).

  FIG. 2 is a block diagram illustrating a configuration example of a control system of the ink jet printer according to the present embodiment. CPU201 controls each part according to the processing procedure etc. which are mentioned later. The ROM 202 stores processing procedures executed by the CPU 201 and predetermined fixed data. The RAM 203 has an area for expanding image data to be recorded, an area for storing parameters used by the CPU 201 in the control process, an area for work, and the like. In addition to the power switch, the operation panel 209 has keys for accepting instructions for setting and changing the recording mode (recording quality, recording speed, etc.) as required by the user and performing other printing operations. Further, the operation panel 209 may be provided with means for notifying or displaying information such as a printer status or an error.

  The head data generation unit 204 converts the image data in accordance with the recording resolution and the like, and further converts it into data in a format according to the configuration and driving mode of the recording head 102 (hereinafter referred to as head data). The head data generation unit 204 has a function of transferring the converted data and driving a recording element provided in the recording head based on the converted data. Data transfer to the recording head or driving of the recording element is performed according to the driving timing generated by the driving timing generation unit 206. The drive pulse generation unit 205 is a unit that generates a pulse signal for driving the recording element of the recording head 102. Similar to the head data generation unit 204, the drive pulse generation unit 205 is driven according to the drive timing generated by the drive timing generation unit 206. Output the signal. The drive timing generation unit 206 generates drive timing in accordance with the position pulse signal output from the optical sensor 103 based on the slit interval of the linear scale 105 as the carriage moves. The head data generation unit 204, the drive pulse generation unit 205, and the drive timing generation unit 206 are connected to the data bus 211 so that the CPU 201 can control each operation and set parameters.

  The recording head 102 has a plurality of recording elements arranged in a direction crossing the carriage movement direction. The recording head 102 according to the present embodiment includes an ejection port for ejecting ink, a liquid path communicating with the ejection port, and an element that generates energy for ejecting ink disposed in the liquid path (hereinafter, these are collectively referred to as a nozzle). ) As a recording element. As an element that generates energy for ejecting ink, a heater that generates heat when energized and causes film boiling in the ink can be used, but other elements in the form of piezo elements may also be used. The recording head 102 performs an AND operation on the head data from the head data generation unit 204 and the drive pulse from the drive pulse generation unit 205, and controls energization to the heater based on the result, and records ink from the ejection port. A circuit for discharging the medium 104 is provided. The linear encoder 208 reads the slits of the linear scale 105 according to the movement of the linear scale 105 formed with a plurality of slits at predetermined intervals and the carriage 101, and outputs a position pulse signal that is a relative position detection signal. Consists of.

  FIG. 3 is a flowchart illustrating an example of a recording processing procedure according to the present embodiment. When this procedure is started, image data is first read (step S1). Next, the recording resolution of the recording head according to the recording mode or the like, or the resolution required for time-division driving by dividing a plurality of nozzles into several blocks (hereinafter referred to as driving resolution) is determined. (Step S3). The CPU 201 stores the value m obtained by dividing the drive resolution by the resolution of the linear encoder in the drive timing generation unit 206 (step S5), transfers the image data to the head data generation unit 204 (step S7), and performs the recording process. Implement (step S9).

  FIG. 4 is a block diagram illustrating an internal configuration example of the drive timing generation unit 206. As described above, the division number register 301 serving as the division number storage unit is a register that can set a value m obtained by dividing the drive resolution by the resolution of the linear encoder. A pulse interval measurement counter 302 as measurement means is a counter for measuring the time interval (cycle) of the position pulse signal from the linear encoder 208. Specifically, the count value is reset to “0” every time a position pulse signal is received, and then the count value is incremented by a system clock (not shown).

  The encoder division number register 303 serving as the division number management means loads the set value m of the division number register 301 every time a position pulse signal is received from the linear encoder 208. Thereafter, it is decremented every time a divided pulse, which is a time division signal for determining the nozzle drive timing, is generated. Therefore, the value stored in the encoder division number register 303 at a certain point in time indicates how many division pulses need to be generated within one cycle of the position pulse signal. The encoder time register 304, which is time management means, loads the value of the pulse interval measurement counter every time a position pulse signal is received from the linear encoder 208, and then decrements the loaded value by a system clock (not shown). Therefore, the value stored in the encoder time register 304 at a certain point in time indicates how much time remains until generation of divided pulses within one cycle of the position pulse signal.

  A division pulse generation unit 305 serving as a time division signal generation unit generates a division pulse when the value of the encoder division number register 303 remains “1” or more. Further, after the division pulse is generated, an operation is performed so as not to generate the next division pulse until the time obtained by dividing the value indicated by the encoder time register by the value indicated by the encoder division number register elapses.

FIG. 5 is a block diagram illustrating a detailed configuration example of the divided pulse generation unit 305.
The division pulse generation start detection unit 401 outputs a division pulse when the number of encoder divisions is 1 or more. However, once the divided pulse is output, the operation is performed so that the next divided pulse is not output until an output value of a subtractor 404 described later becomes a negative number. The divisor register 402 loads the value of the encoder division number register 303 when the division pulse is output. The temporary register 403 loads the value of the encoder time register 304 when the divided pulse is output, and thereafter loads the output of the subtractor 404 every system clock. The subtractor 404 outputs a value obtained by subtracting the value of the divisor register 402 from the value of the temporary register 403.

  With the above-described configuration, the encoder position pulse signal detected when the carriage 101 moves and the output operation of the divided pulses will be described using a timing chart.

  FIG. 6 is a timing chart showing an encoder position pulse signal when the carriage 101 is moving at a constant speed and each signal inside the drive timing generation unit 206. Here, the operation when outputting three divided pulses for one period of the position pulse signal is illustrated. The position pulse signal is detected at the rising timing.

  In FIG. 6, in the period T0, one period of the position pulse signal (pulse interval from the rising of the preceding position pulse signal to the rising of the next position pulse signal) is measured. Then, the set value (m = 3) of the division number register 301 is added to the value of the encoder division number register 303 at the rising timing (A) of the next position pulse signal. Since three divided pulse signals have already been output from the rise of the preceding position pulse signal and the content of the encoder division number register 303 is “0”, “3” is set again in the encoder division number register 303. The At the same timing (A), the encoder time register 304 is set with the time interval (cycle) T0 of the previous position pulse signal. At this timing, since a value of 1 or more (= 3) is set in the encoder division number register 303, the division pulse generation unit 305 outputs the first division pulse in the period T1 of the next position pulse signal. . When the first division pulse is output, the encoder division number register 303 is immediately decremented and the content becomes “2”.

  When the divided pulse generator 305 outputs the divided pulse, it stores the value of the period T0 loaded in the encoder time register 304 and the value of the encoder division number register 303, outputs the divided pulse, and then outputs T0 / 3. Until the time elapses, the operation is performed so as not to generate the next divided pulse. Then, at the timing (B) when T0 / 3 has elapsed, the second division pulse is output, the value of the encoder time register 304 is T0-T0 / 3 = T0 × 2/3, and the value of the encoder division number register 303 is “1”. The timing for outputting the next divided pulse is the timing (C) when T0 × 2/3/2 = T0 / 3 has passed. At this timing (C), the third division pulse is output, the value of the encoder time register 304 is T0 × 2 / 3−T0 / 3 = T0 / 3, and the value of the encoder division number register 303 is “0”. Become. Therefore, at the timing (D) when T0 / 3 further elapses, the next divided pulse based on the pulse period T0 is not output. However, since FIG. 6 is based on the assumption that the carriage 101 is moving at a constant speed, at this timing (D), the rising edge of the next position pulse signal is detected and a divided pulse based on the period T1 is output. Will be. By repeating the above operation, the divided pulses can be generated at a timing synchronized with the position pulse detection timing of the encoder, and the recording head can be driven at an accurate position.

  FIG. 7 is a timing chart showing the encoder position pulse signal when the carriage 101 is moving at a constant speed and each signal inside the drive timing generation unit 206 as in FIG. However, this figure illustrates the operation when outputting six divided pulses for one period of the position pulse signal. As shown in the figure, even when the number of divisions increases, divided pulses can be generated at the timing synchronized with the position pulse detection timing of the encoder by the same operation as described above, and recorded at an accurate position. The head can be driven.

  FIG. 8 is a timing chart of the encoder position pulse signal and each signal in the drive timing generation unit 206 in the present embodiment when the carriage 101 has a speed variation. The same setting as that in the case of FIG. 7 is performed for each register. FIG. 9 shows a timing chart of each signal when the technique of Patent Document 1 is applied for comparison. In these drawings, for the sake of simplification of explanation, it is assumed that speed fluctuation (increase in speed) occurs in the period T0, and movement at a constant speed is performed after the period T1. In this case, in the period T1, the next position pulse is detected in a state where only five divided pulses based on the period T1 are output.

  In the case of the present embodiment shown in FIG. 8, since the value of the encoder division number register 304 is “1” at the timing when the fifth division pulse is output and T1 has elapsed, When (m = 6) is added, it becomes “7”. At the same time, the value of the encoder time register 304 is updated to T1. The value of the encoder time register 304 after the lapse of T0 / 6 after the output of the fifth divided pulse is a value obtained by subtracting the difference between the period T0 × 5/6 and the period T1 from the period T1. (T1- (T0 × 5 / 6-T1)) remains. Therefore, thereafter, seven divided pulses are generated with a period (T1− (T0 × 5 / 6−T1)) / 7. As described above, since the movement at the constant speed is performed after the period T1, the operation after the period T2 is the same as that when the movement at the constant speed shown in FIG. 7 is performed.

  On the other hand, when the technique described in Patent Document 1 in which correction is performed for each cycle of the encoder position pulse signal is applied, the following problem occurs. That is, as shown in FIG. 9, even if the rising of the next position pulse signal is detected in a state where only five divided pulse signals have been generated, the sixth divided pulse signal is the same as the previous position pulse signal. It is output at a timing determined based on the cycle. Accordingly, the feedback of the speed fluctuation to the divided pulse signal is delayed, and the time interval of the divided pulse signal output is extremely shortened in the period of the next position pulse signal. That is, when the technique described in Patent Document 1 is applied, the phase difference between the position pulse signal and the divided pulse signal is larger than that in FIG. 8 according to the embodiment of the present invention. It is clear from 9.

  FIG. 10 is a block diagram illustrating another configuration example of the drive timing generation unit 206 illustrated in FIG. 4. Components that are configured and function similarly to FIG. 4 are denoted by the same reference numerals. The configuration shown in FIG. 10 can generate a drive timing signal at an interval obtained by multiplying one cycle of the encoder signal by m / n (m and n are arbitrary integers). A register 501 and a magnification counter 502 are added.

Here, the magnification register 501 is a register that can be set by the CPU 201, and sets a coefficient for conversion from the resolution of the linear encoder to the drive resolution in combination with the division number register 301. The magnification counter 502 counts the number of divided pulses output from the divided pulse generation unit 305. When the count value reaches the value n set in the magnification register 501, a drive signal for determining the drive timing is generated once and the count value is cleared to “0”. With the above configuration, the value n set in the magnification register 501 and the value m set in the division number register 301 can be used to perform conversion from the resolution of the linear encoder to a desired drive resolution according to the following equation.
Drive resolution = linear encoder resolution x m / n

  For example, when the linear encoder resolution is 150 lpi and the drive resolution is 1200 lpi, m = 8 and n = 1 are set. When a drive pulse with a drive resolution of 800 lpi is generated by the same linear encoder, m = 16 and n = 3 are set. These values are calculated as the least common multiple of the linear encoder resolution and the drive resolution, m is obtained by dividing the least common multiple by the linear encoder resolution, and n is obtained by dividing the least common multiple by the drive resolution. Can be set to These calculations can be performed by the CPU 201, that is, by a process corresponding to step S5 in the flowchart of FIG.

  According to the above embodiment, the recording of the output image can be freely changed with respect to the resolution of the encoder, and an image can be formed at an accurate timing even when the speed fluctuates. An apparatus can be provided. For this reason, it is possible to change the print density in the printer body as follows. That is, when an instruction to change the recording density is received from the user via the operation panel 209 or the like, the CPU 201 changes the resolution of the head data and the recording resolution so that a desired density is obtained. For example, when adjusting the density of the image data by a desired number of times, the resolution of the head data may be increased to the desired number of times, and the recording resolution may be changed to the desired number of times.

  In the above embodiment, the value set in the register is performed by the arithmetic processing by the CPU 201. However, for example, values corresponding to a plurality of drive resolutions are calculated in advance, stored as a table in the ROM 202, and values corresponding to the drive resolution designated by the user are read from the table via the operation panel 209 and set. You may do it.

  In the above-described embodiment, the case where the present invention is applied to a so-called serial printer type ink jet recording apparatus that moves a recording head relative to a recording medium and performs recording in the process of the movement has been described. However, the present invention can be effectively applied to any recording apparatus that performs recording while relatively moving the recording head and the recording medium. That is, a so-called line printer type ink jet recording apparatus that uses a recording head in which recording elements are arranged over a range corresponding to the width of the recording medium, transports the recording medium to the recording head, and performs recording in the transport process. It can also be applied to.

  Furthermore, in the above example, the present invention has been described with respect to the configuration in which the relative position between the recording head and the recording medium is detected by the linear encoder. However, for example, in a line printer, the present invention can also be effectively applied to a configuration in which the recording medium conveyance position is detected by a roller that carries the recording medium or a rotary encoder attached to the shaft of a motor that drives the recording medium. is there.

  In addition, the form of the recording head used in the recording apparatus is not limited to the ink jet recording head as described above, and it goes without saying that various types can be adopted.

102 recording head 201 CPU
204 Head Data Generation Unit 205 Drive Pulse Generation Unit 206 Drive Timing Generation Unit 208 Linear Encoder 301 Division Number Register 302 Pulse Interval Measurement Counter 303 Encoder Division Number Register 304 Encoder Time Register 305 Division Pulse Generation Unit 501 Magnification Register 502 Magnification Counter

Claims (3)

Recording is performed by moving the recording head and the recording medium relative to each other, converting the resolution of the relative position detecting means for detecting the relative movement position to a different resolution, and driving the recording head based on the converted resolution. A recording device,
Measuring means for measuring a period of a relative position detection signal generated by the relative position detecting means in response to the relative movement;
Each time the relative position detection signal is generated, a time management unit that loads a value indicating the period measured by the measurement unit and subtracts it according to the passage of time;
Division number storage means for storing the number of divisions for time-dividing the period to perform the conversion;
Each time the relative position detection signal is generated, the division number stored in the division number storage means is loaded, and the time division signal used to determine the drive timing of the recording head is determined based on the loaded division number. A division number management means for subtracting one by one for each output;
A time division signal generating means for outputting the time division signal when the value remaining in the division number management means is 1 or more, wherein after the time division signal is outputted, the value indicated by the time management means is obtained; Time division signal generation means for not outputting the next time division signal until the time divided by the value indicated by the division number management means elapses;
A recording apparatus comprising:   2. The recording apparatus according to claim 1, further comprising means for outputting a driving signal for determining a driving timing of the recording head every time a predetermined number of the time division signals are output.   The recording head performs recording in the process of moving with respect to the recording medium, and the position detecting means is provided along the direction of the movement, and a linear scale in which a plurality of slits are formed, and the recording head The recording apparatus according to claim 1, further comprising a linear encoder having a sensor that moves together with the sensor to detect the slit.

Images