JP6102915B2 - Image recording device - Google Patents

Description

  The present invention relates to an image recording apparatus.

Today, an inkjet image recording apparatus that records an image by ejecting ink onto a recording medium is used. In such an image recording apparatus, a single pass type or a scan type is known as a scanning method on a recording medium of a recording head for ejecting ink droplets.
In the single-pass image recording apparatus, the recording medium moves relative to the recording head by being conveyed. In a scanning image recording apparatus, a recording head is mounted on a carriage and reciprocates in the main scanning direction, and the recording medium is conveyed in the sub-scanning direction. Patent document 1 is given as an example of the latter.
In any case, an image is recorded by ejecting ink from the recording head at a timing synchronized with the relative movement between the recording head and the recording medium. For this purpose, the ink ejection timing of the recording head is controlled based on a pulse synchronized with the movement input from the encoder that detects the relative movement between the recording head and the recording medium. This will be described with reference to an example shown in FIG.

The graph G1 in FIG. 7 shows the input pulse signal. The input pulse signal is a pulse signal input from the encoder described above or a pulse signal obtained by dividing the pulse signal.
The control device of the image recording apparatus measures the period of the input pulses P1, P2,... Based on the reference clock signal shown in the graph G2 of FIG. That is, the periods T1, T2,... Shown in the graph G1 of FIG.
When the measurement of the cycle T1 ends, the control device generates a multiplied pulse P1a obtained by multiplying the input pulse P1 having the cycle T1 by a preset multiplication number as shown in a graph G3 in FIG. Sequentially, multiplication pulses P2a, P3a,... Are generated for the subsequent input pulses P2, P3,. In the example of FIG. 7, the multiplication number is 5.
Based on the multiplied pulse signal shown in the graph G3 of FIG. 7 obtained in this way, the ink ejection timing signal shown in the graph G4 of FIG. 7 is generated. The ejection timing signal shown in the graph G4 in FIG. 7 is an example in which ejection is performed once every 5 cycles of the multiplied pulse shown in the graph G3 in FIG.

JP 2006-68953 A

However, the above prior art has the problems described below.
This will be described with reference to graphs G1 to G4 in FIG. FIG. 8 shows a case where the period of the input pulse is disturbed due to the disturbance in the conveyance under the same conditions as in the example shown in FIG. Specifically, the case where the periods T5 and T6 of the input pulses P5 and P6 are longer than the periods T1, T2, T3 and T4 of the input pulses P1, P2, P3 and P4 and returns to the original after P7 is shown. In such a case, a problem arises when the conveyance is delayed, that is, when the cycle is long.
At time t1 shown in FIG. 8, the measurement of the input pulse P1 is completed, and generation of the multiplied pulse P1a is started. Subsequent to the multiplication pulse P1a, measurement of the input pulse P2 is completed at time t2, and generation of the multiplication pulse P2a is started. Similarly, the multiplication pulse P3a and the multiplication pulse P4a are continuously generated. Since the measurement of the input pulse P5 is not completed at the time t5 when the generation of the multiplied pulse P4a is completed, the time is awaited, and the generation of the multiplied pulse P5a is started at the time t6 when the measurement of the input pulse P5 is completed. Therefore, a blank period TB corresponding to the time from time t5 to time t6 occurs. Such a blank period TB does not occur after the multiplication pulse P5a, and there is no problem.

If the ejection timing signal is generated only in accordance with the fluctuation of the pulse period (T1 to T7...) Of the multiplied pulse P1a to the multiplied pulse P7a..., The timing is synchronized with the relative movement between the recording head and the recording medium. There is no problem because ink is ejected from the recording head. In the illustrated example, there is no problem because the ejection timing interval R1 shown in the graph G4 in FIG. 8 corresponds to 10 cycles of the multiplied pulse obtained by combining the multiplied pulse P1a and the multiplied pulse P2a. There is no problem with the discharge timing intervals R1, R2, and R4 as well.
However, the ejection timing interval R3 becomes longer by the blank period TB in addition to 10 cycles of the multiplied pulse including the multiplied pulse P5a and the multiplied pulse P6a (R3 = TB + T5 + T6).
Therefore, the ink interval is widened by an amount corresponding to the blank period TB with respect to an image recorded on the recording medium accurately according to the image information, resulting in a problem of deterioration in recording image quality.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an image recording apparatus capable of processing an input pulse signal from an encoder so as not to cause a decrease in recording image quality even when the recording medium transport or the recording head transport is disturbed. And

The invention according to claim 1 for solving the above problem is an image recording apparatus for controlling a recording operation of the recording head in synchronization with a relative movement between the recording head and a recording medium.
An encoder that detects the relative movement and generates a pulse signal synchronized therewith;
A period measuring unit that measures the period of the pulse signal synchronized with the relative movement based on the pulse signal input from the encoder;
A plurality of period measurement value holding units that alternately store and hold the period measurement values measured by the period measurement unit;
A division unit for outputting a quotient and a remainder obtained by dividing the period measurement value stored in the period measurement value holding unit by a multiplication number;
A frequency-multiplied pulse signal obtained by multiplying a pulse signal having a period corresponding to a period measurement value by the multiplication number while changing the application source of the period measurement value from the plurality of period measurement value holding units according to the measurement order is output from the division unit. If the remainder can be distributed to a plurality of multiplication pulses based on the quotient and the remainder, a multiplication pulse generator that generates the distribution, and
An output timing signal generation unit that generates an output timing signal of the recording operation based on the multiplied pulse signal, and
When the multiplied pulse generation unit generates a multiplied pulse signal based on the cycle measurement value stored and held in one cycle measurement value holding unit that is an application source of the plurality of cycle measurement value holding units, The period measurement value already measured after the period measurement value stored and held in the period measurement value holding unit is stored and held in another period measurement value holding unit,
The division unit is an image recording apparatus provided in a plurality corresponding to the plurality of period measurement value holding units.

The invention according to claim 2 is the image recording apparatus according to claim 1, wherein the total number of the plurality of period measurement value holding units provided corresponding to the one period measurement unit is 4 or 5.
A third aspect of the present invention is the image recording apparatus according to the first or second aspect, further comprising a multiplication setting unit for setting the multiplication number, wherein the multiplication number can be changed.
According to a fourth aspect of the present invention, the period measuring unit determines how many periods of the reference clock signal correspond to the period of the pulse signal based on the reference clock signal and the pulse signal input from the encoder. Measure the counted count value as the period of the pulse signal,
The multiplication pulse generator generates a multiplication pulse signal by distributing the remainder to a plurality of multiplication pulses when the remainder when the count value is divided by the multiplication number is 2 or more. An image recording apparatus according to claim 1.
A fifth aspect of the present invention is the image recording apparatus according to any one of the first to fourth aspects, wherein the output timing signal includes an output timing signal having a period longer than a period of the multiplied pulse signal.
According to a sixth aspect of the present invention, in the encoder according to any one of the first to fifth aspects, the encoder is attached to a recording medium conveyance device, detects the relative movement due to the conveyance of the recording medium, and generates a pulse signal synchronized therewith. An image recording apparatus according to claim 1.
The invention according to claim 7 includes a frequency dividing circuit that divides the pulse signal input from the encoder,
The image recording apparatus according to claim 1, wherein the period measuring unit measures a period of the pulse signal synchronized with the relative movement based on the pulse signal divided by the frequency dividing circuit. is there.
The invention according to claim 8 includes an output timing period setting unit that sets a period of the output timing signal based on the multiplied pulse signal, and the period of the output timing signal can be changed. An image recording apparatus according to any one of the above.

According to the present invention, it is provided with a plurality of period measurement value holding units for sequentially storing and holding the period measurement values measured by the period measurement unit, and the multiplying pulse generation unit receives the period measurement values from the plurality of period measurement value holding units. Generates a multiplied pulse signal by multiplying the pulse signal of the cycle corresponding to the cycle measurement value while changing the application source according to the measurement order, and based on the cycle measurement value stored and held in one cycle measurement value holding unit When generating the multiplied pulse signal, the cycle measurement value already measured after the cycle measurement value stored and held in the one cycle measurement value holding unit is stored and held in the other cycle measurement value holding unit.
For this reason, the period being measured is longer than any of the period measurement values stored and held in the period measurement value holding unit, and the measurement period is prolonged due to disturbance in the conveyance of the recording medium and the conveyance of the recording head. Even when the generation of the multiplied pulse signal is completed, the next period measurement value stored and held in another period measurement value holding unit is applied, so that the above-described blank period TB is continuously generated. A multiplied pulse signal can be generated.
In addition, it has a division unit that outputs the quotient obtained by dividing the period measurement value stored in the period measurement value holding unit by the multiplication factor and the remainder, and the multiplication pulse generation unit outputs the multiplied pulse signal that has been multiplied. If the remainder can be distributed to a plurality of multiplied pulses based on the quotient and the remainder, the remainder is distributed and generated.
As described above, according to the present invention, it is possible to process the input pulse signal from the encoder so as not to cause deterioration in the recording image quality even when the conveyance of the recording medium or the conveyance of the recording head is disturbed.

FIG. 3 is a functional block diagram illustrating a signal processing unit that generates a discharge timing signal of a recording head in an image recording apparatus according to an embodiment of the present invention. It is a pulse signal waveform diagram for explaining the processing contents until the generation of the multiplied pulse signal in the signal processing unit according to the embodiment of the present invention. It is a pulse signal waveform diagram for explaining the processing content until the generation of the ejection timing signal in the signal processing unit according to an embodiment of the present invention, the period measurement value holding unit is five, the input pulse signal is disturbed In other words, there is shown a case where there is a difference of two cycles between the measurement of the input pulse signal and the generation of the multiplied pulse to which this is applied. FIG. 4 is a pulse signal waveform diagram for explaining processing contents until generation of an ejection timing signal in a signal processing unit according to an embodiment of the present invention, and shows a case where disturbance occurs in an input pulse signal under the same conditions as in FIG. 3. Show. It is a pulse signal waveform diagram for explaining the processing content until the generation of the ejection timing signal in the signal processing unit according to an embodiment of the present invention, the period measurement value holding unit is five, the input pulse signal is disturbed There is a case where there is an initial deviation of three cycles between the measurement of the input pulse signal and the generation of the multiplied pulse to which this is applied. It is a pulse signal waveform diagram for explaining the processing content until the generation of the ejection timing signal in the signal processing unit according to one embodiment of the present invention, the period measurement value holding unit is four, the input pulse signal is disturbed Yes, there is shown a case where there is an initial shift of two cycles between the measurement of the input pulse signal and the generation of the multiplied pulse to which this is applied. It is a pulse signal waveform diagram for demonstrating the processing content until the production | generation of the discharge timing signal in the signal processing part which concerns on a prior art example, and shows the case where there is no disorder in an input pulse signal. FIG. 9 is a pulse signal waveform diagram for explaining processing contents until generation of an ejection timing signal in a signal processing unit according to a conventional example, and shows a case where disturbance occurs in an input pulse signal under the same conditions as in FIG.

  An embodiment of the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention.

In the single-pass image recording apparatus, the recording medium moves relative to the recording head by being conveyed. In a scanning image recording apparatus, a recording head is mounted on a carriage and reciprocates in the main scanning direction, and the recording medium is conveyed in the sub-scanning direction.
The image recording apparatus of the present embodiment is of a single-pass type or a scan type, and controls the recording operation of the recording head in synchronization with the relative movement between the recording head and the recording medium. Record the image on top.
An example of the recording head is one that ejects ink toward a recording medium. Therefore, in this embodiment, the recording operation of the recording head is an ink ejection operation. In addition to a recording material other than ink, a recording method that realizes image formation on the recording medium by applying energy such as heat or light may be applied to the recording medium. This is because in any recording method, it is necessary to control the recording operation of the recording head in synchronization with the relative movement between the recording head and the recording medium.
The image recording apparatus includes an encoder that detects a relative movement between the recording head and the recording medium and generates a pulse signal synchronized with the relative movement. In the single-pass system, an encoder is attached to the recording medium conveyance device. In the scanning type, it is further attached to the recording head transport device.
The control device of the image recording apparatus that controls the ink discharge operation of the recording head generates the discharge timing signal based on the input pulse signal from the encoder.

FIG. 1 shows a functional block diagram of a signal processing unit 1 that generates an ejection timing signal based on an input pulse signal from an encoder.
As shown in FIG. 1, the signal processing unit 1 includes a frequency divider circuit 10, a frequency division value setting unit 11, a measurement cycle counter 12, a generation cycle counter 13, a period measurement unit 14, and five period measurement value holding units 20. To 24, five division units 30 to 34, a multiplication number setting unit 15, a multiplication pulse generation unit 16, a discharge timing signal generation unit 17, and a discharge timing cycle setting unit 18. Here, the total number of period measurement value holding units is five as an example.

An input pulse signal d from the encoder is input to the frequency dividing circuit 10. The reference clock signal CL is input to the frequency dividing circuit 10, the period measuring unit 14, and the multiplied pulse generating unit 16, respectively. The frequency dividing circuit 10 outputs an input pulse signal e obtained by dividing the input pulse signal d to each of the measurement cycle counter 12 and the generation cycle counter 13. The frequency dividing value setting unit 11 is a part for setting the frequency dividing number in the frequency dividing circuit 10. When the frequency division number is 1, input pulse signal d = input pulse signal e. In this example, the functional block diagram shows the case where the frequency dividing circuit is provided. However, the frequency dividing circuit may be omitted if it is not necessary for the realization.
The measurement cycle counter 12 repeatedly counts up to five pulse units of the input pulse signal e. For the sake of explanation, this count value is assumed to be a pulse ordinal number M, and the pulse ordinal number M can take values of “0”, “1”, “2”, “3”, and “4”. The measurement cycle counter 12 counts up from “0” to “4”, returns to “0” after “4”, and repeats counting up.
The measurement cycle counter 12 outputs the pulse ordinal number M to the period measurement unit 14 and outputs a measurement timing signal i every time it counts up. The measurement timing signal i only needs to correspond to the rising timing of the pulse of the input pulse signal e. That is, the measurement cycle counter 12 causes the period measurement unit 14 to calculate the pulse ordinal numbers “0”, “1”, “2”, “3”, and “4”, the pulse specified by the pulse ordinal number, and the previous pulse. Output the break timing. The pulse ordinal number is updated simultaneously with the output of the pulse-to-pulse separation timing.

The period measuring unit 14 measures the pulse period of the input pulse signal e based on the reference clock signal CL. That is, measurement is performed by counting how many cycles of the reference clock signal CL corresponds to the cycle of the input pulse. For example, when the rising edge of the input pulse signal e is detected by the input of the measurement timing signal i, the period measurement is started by the counter that performs the counting operation with the reference clock signal CL, and the time until the next rising of the input pulse signal e is counted. Thus, the period of the input pulse signal e can be measured.
When the period measuring unit 14 measures the pulse period with the pulse ordinal number M being “0”, the period measuring unit 14 outputs the pulse period measured value to the period measured value holding unit 20, and the period measured value holding unit 20 receives the next input. Hold up to. The division unit 30 outputs the quotient obtained by dividing the pulse period measurement value held in the period measurement value holding unit 20 by the multiplication number and the remainder to the multiplication pulse generation unit 16.
When the cycle measuring unit 14 measures the pulse cycle with the pulse ordinal number M being “1”, the cycle measuring unit 14 outputs the pulse cycle measured value to the cycle measured value holding unit 21, and the cycle measured value holding unit 21 receives the next input. Hold up to. The division unit 31 outputs the quotient obtained by dividing the pulse period measurement value held in the period measurement value holding unit 21 by the multiplication number and the remainder to the multiplication pulse generation unit 16.
When the cycle measuring unit 14 measures the pulse cycle with the pulse ordinal number M being “2”, the cycle measuring unit 14 outputs the pulse cycle measured value to the cycle measured value holding unit 22, and the cycle measured value holding unit 22 receives the next input. Hold up to. The division unit 32 outputs the quotient obtained by dividing the pulse period measurement value held in the period measurement value holding unit 22 by the multiplication number and the remainder to the multiplication pulse generation unit 16.
When the period measuring unit 14 measures a pulse period with a pulse ordinal number M of “3”, the period measuring unit 14 outputs a pulse period measured value to the period measured value holding unit 23, and the period measured value holding unit 23 receives the next input. Hold up to. The division unit 33 outputs the quotient obtained by dividing the pulse cycle measurement value held in the cycle measurement value holding unit 23 by the multiplication number and the remainder to the multiplication pulse generation unit 16.
When the cycle measuring unit 14 measures a pulse cycle with a pulse ordinal number M of “4”, it outputs a pulse cycle measured value to the cycle measured value holding unit 24, and the cycle measured value holding unit 24 receives the next input. Hold up to. The division unit 34 outputs the quotient obtained by dividing the pulse cycle measurement value held in the cycle measurement value holding unit 24 by the multiplication number and the remainder to the multiplication pulse generation unit 16.
The pulse period measurement value is output by the count value based on the reference clock signal and the latch signal.
As described above, the five period measurement value holding units 20 to 24 alternately store and hold the period measurement values measured by the period measurement unit 14 in order.

Similarly to the measurement cycle counter 12, the generation cycle counter 13 repeatedly counts up to five pulse units of the input pulse signal e divided by the frequency dividing circuit 10. However, the generation cycle counter 13 holds the input pulse signal e, and counts from “0” triggered by the count start signal k input from the measurement cycle counter 12. For example, when the generation timing is delayed by two periods with respect to the measurement timing, the measurement cycle counter 12 outputs the count start signal k to the generation cycle counter 13 when outputting “2” as the pulse ordinal M to the period measurement unit 14, The generation cycle counter 13 outputs “0” as the pulse ordinal number N to the multiplied pulse generator 16. The pulse assigned to the pulse ordinal “0” by the measurement cycle counter 12 and the pulse assigned to the pulse ordinal “0” by the generation cycle counter 13 are the same pulse (“1”, “2”, “3”, “4”). The same applies to the case).
The generation cycle counter 13 outputs the generation timing signal j while outputting the pulse ordinal number N to the multiplied pulse generation unit 16 every time it counts up. It is sufficient that the measurement timing signal i and the generation timing signal j correspond to the rising timing of the pulse of the input pulse signal e. That is, the measurement cycle counter 12 and the generation cycle counter 13 respectively send the pulse ordinal numbers “0”, “1”, “2”, “3”, and “4” to the period measurement unit 14 and the multiplied pulse generation unit 16 and the pulse ordinal numbers. The timing of the division between the specified pulse and the previous pulse is output. The pulse ordinal number is updated simultaneously with the output of the pulse-to-pulse separation timing.

When “0” is input as the pulse ordinal number N, the multiplication pulse generation unit 16 generates a multiplication pulse by applying the period measurement value stored and held in the period measurement value holding unit 20. The multiplication pulse generator 16 generates a multiplication pulse based on the quotient obtained by dividing the applied period measurement value by the multiplication number and the remainder. In the present embodiment, since the division units 30 to 34 in the previous stage of the multiplication pulse generation unit 16 calculate the quotient and the remainder, the multiplication pulse generation unit 16 applies this. The multiplication number is set in the multiplication number setting unit 15 in advance.
For example, when the multiplication number is set to 5 and the cycle measurement value stored and held in the cycle measurement value holding unit 20 is 20 counts (1 count is one cycle of the reference clock signal CL), the division unit 30 Since the quotient 4 and the remainder 0 are output to the multiplied pulse generator 16, the multiplied pulse generator 16 applies this, and generates a multiplied pulse signal f having a length of 4 counts for one period. In this case, one pulse of the multiplied pulse signal f has a length corresponding to four cycles of the reference clock signal CL.
Similarly, when “1” is input as the pulse ordinal number N, the multiplication pulse generation unit 16 applies the period measurement value stored and held in the period measurement value holding unit 21 to generate a multiplication pulse, that is, a division unit. The multiplication pulse is generated by applying the quotient calculated by 31 and the remainder. Even when the pulse ordinal number N is “2”, “3”, or “4”, the multiplication pulse generation unit 16 generates the multiplication pulses in the same manner with the application source as the period measurement value holding units 22, 23, and 24 in order.
As described above, the multiplied pulse generation unit 16 generates the multiplied pulse signal f obtained by multiplying the pulse signal having the period corresponding to the period measurement value while changing the application source of the period measurement value according to the measurement order.

In the case where the remainder is generated by introducing the cycle measurement value by the multiplication number, the multiplication pulse generator 16 processes as follows.
As shown in FIG. 2, when the input pulse signal e (graph G1 in FIG. 2) can be counted 20 times with the reference clock signal CL (graph G2 in FIG. 2), if the multiplication number is 3, the quotient is 6 2. As shown in the graph G3 of FIG. 2, when the multiplied pulse signal is generated by dividing the reference clock signal CL by 6 cycles from the beginning, the third multiplied pulse is the reference clock signal CL for 2 cycles (displayed in the section 101). It will only be longer than others.
In order to make the multiplied pulse as uniform as possible, when the remainder is 2 or more, the remainder is divided and distributed to different multiplied pulses. For example, as shown in the graph G4 of FIG. 2, one of the remainders 2 is distributed to the first multiplied pulse (displayed in the section 102), and the remaining one is distributed to the second multiplied pulse (in the section 103). display). When the remainder is 1, it may be distributed to any multiplied pulse. Further, as shown in the graph G4 of FIG. 2, the remainder may be distributed by increasing the Hi side of the multiplied pulse by one cycle, or although not shown, it is distributed by increasing the Low side by one cycle. May be.

  The discharge timing signal generator 17 generates the discharge timing signal g with reference to the multiplied pulse signal f generated by the multiplied pulse generator 16. The discharge timing cycle setting unit 18 sets a discharge timing cycle based on the multiplied pulse signal f. An example of generating the discharge timing signal g is shown by the respective graphs G1 to G5 in FIGS.

In the example shown in FIGS. 3 to 6, the multiplication number is set to 5.
In the example shown in FIGS. 3 to 5, there are five period measurement value holding units. In the example shown in FIG. 6, there are four period measurement value holding units.
In the example shown in FIGS. 3, 4, and 6, the generation timing is delayed by two cycles with respect to the measurement timing. In the example shown in FIG. 5, the generation timing is delayed by three cycles with respect to the measurement timing. The delay of the generation timing with respect to the measurement timing changes due to the change in the period of the input pulse signal e. As shown in FIG. 1, when the five period measurement value holding units 20 to 24 are provided, the delay time of the generation timing with respect to the measurement timing can correspond to a maximum of five periods.
The pulse ordinal numbers handled by the measurement cycle counter 12 and the generation cycle counter 13 correspond to the number of period measurement value holding units, and are “0” to “4” in FIGS. 3 to 5 and FIG. Is changed from “0” to “3”, which are indicated by the same numbers in the graphs G2 and G3 in the figure.
FIGS. 3 to 6 show, as an example, an ejection timing signal g for performing ejection once in 10 cycles of the multiplied pulse signal f.

  The input pulse signal e shown in the graph G1 of FIG. 3 is input, and the pulse period of the pulse ordinal number M indicated by the measurement cycle counter 12 is measured as shown in the graph G2 of FIG. As shown in the graph G3 of FIG. 3, the generation cycle counter 13 indicates the pulse ordinal number N (= “simultaneous value of M” −2) delayed by two cycles with respect to the measurement cycle counter 12, and the graph G4 of FIG. As shown in FIG. 5, the pulse period of the pulse ordinal number N indicated by the generation cycle counter 13 is multiplied to generate a multiplied pulse signal f. A discharge timing signal g is generated based on the multiplied pulse signal f.

Assume that the conveyance is disturbed and the input pulse signal e is disturbed as shown in FIG. 4 under the same conditions as those shown in FIG. In FIG. 4, the pulses corresponding to the pulse ordinal numbers “0” and “1” on the second side are longer than others. In such a case, as described with reference to FIG. 8, the blank period TB occurs in the conventional technique. This is due to the fact that the measurement of the next pulse period has not been completed when the multiplication process is completed.
However, in the signal processing unit 1 of the present embodiment, the signal is processed as shown in FIG. At the time of starting the measurement of the pulse corresponding to the pulse ordinal number “0” on the second surface shown in the graph G2 in FIG. 4, two pulses from the pulse ordinal number “0” on the second surface as shown in the graph G3 in FIG. Generation of a pulse corresponding to the previous ordinal number “3” is started. Therefore, even if the pulse corresponding to the pulse number “0” on the second side is prolonged, the measurement of the pulse corresponding to the pulse number “0” on the second side is completed if the length of the pulse is within one cycle. The generation of the pulse corresponding to the pulse ordinal number “4” on the first side has been completed, and the period of the pulse to be multiplied next time, that is, the pulse corresponding to the pulse ordinal number “0” on the second side is measured. The value can be applied without waiting time, and the multiplied pulse signal f can be continuously generated without generating the blank period TB.

  In the example shown in FIG. 5, since the generation timing is delayed by three cycles with respect to the measurement timing, if the prolongation for this state is within two cycles, the blank period TB is not generated. The multiplied pulse signal f can be generated continuously.

As described above, the signal processing unit 1 is based on the cycle measurement value stored and held in one cycle measurement value holding unit (for example, 20) that is the application source among the plurality of cycle measurement value holding units (20 to 24). When the multiplied pulse generator 16 generates the multiplied pulse signal f, the cycle measurement value already measured after the cycle measurement value stored and held in the one cycle measurement value holding unit (20) It is stored and held in the period measurement value holding unit (21, 22).
Therefore, as described above, the multiplied pulse signal f is continuously generated without generating the blank period TB so that the recording image quality is not deteriorated even if the conveyance of the recording medium or the conveyance of the recording head is disturbed. The input pulse signal from the encoder can be processed.

  In order to obtain the above effects, the total number of the plurality of period measurement value holding units is preferably 2 to 5. By setting it to 2 or more, in order to absorb conveyance disturbance by signal processing, it is possible to provide an effective delay with respect to the measurement timing of the generation timing. On the other hand, by setting it to 5 or less, it is possible to effectively absorb conveyance disturbance and to prevent excessive delay.

  The present invention can be used for recording an image on a recording medium.

1 signal processing unit 10 frequency dividing circuit 11 frequency division value setting unit 12 measurement cycle counter 13 generation cycle counter 14 period measurement unit 15 multiplication number setting unit 16 multiplication pulse generation unit 17 discharge timing signal generation unit 18 discharge timing cycle setting unit 20 − 24 Period measurement value holding unit 30-34 Division unit TB Blank period

Claims (8)

An image recording apparatus for controlling a recording operation of the recording head in synchronization with a relative movement between the recording head and a recording medium,
An encoder that detects the relative movement and generates a pulse signal synchronized therewith;
A period measuring unit that measures the period of the pulse signal synchronized with the relative movement based on the pulse signal input from the encoder;
A plurality of period measurement value holding units that alternately store and hold the period measurement values measured by the period measurement unit;
A division unit for outputting a quotient and a remainder obtained by dividing the period measurement value stored in the period measurement value holding unit by a multiplication number;
A frequency-multiplied pulse signal obtained by multiplying a pulse signal having a period corresponding to a period measurement value by the multiplication number while changing the application source of the period measurement value from the plurality of period measurement value holding units according to the measurement order is output from the division unit. If the remainder can be distributed to a plurality of multiplication pulses based on the quotient and the remainder, a multiplication pulse generator that generates the distribution, and
An output timing signal generation unit that generates an output timing signal of the recording operation based on the multiplied pulse signal, and
When the multiplied pulse generation unit generates a multiplied pulse signal based on the cycle measurement value stored and held in one cycle measurement value holding unit that is an application source of the plurality of cycle measurement value holding units, The period measurement value already measured after the period measurement value stored and held in the period measurement value holding unit is stored and held in another period measurement value holding unit,
A plurality of the division units are provided corresponding to the plurality of period measurement value holding units.   The image recording apparatus according to claim 1, wherein a total number of the plurality of period measurement value holding units provided corresponding to one period measurement unit is four or five. The image recording apparatus according to claim 1, further comprising a multiplication setting unit that sets the multiplication number, wherein the multiplication number can be changed. The cycle measuring unit counts a count value obtained by counting how many cycles of the reference clock signal the cycle of the pulse signal is based on a reference clock signal and a pulse signal input from the encoder. Measured as the period of
The multiplication pulse generator generates a multiplication pulse signal by distributing the remainder to a plurality of multiplication pulses when the remainder when the count value is divided by the multiplication number is 2 or more. An image recording apparatus according to claim 1.   The image recording apparatus according to claim 1, wherein the output timing signal includes an output timing signal having a period longer than a period of the multiplied pulse signal.   The image recording apparatus according to claim 1, wherein the encoder is attached to a recording medium conveyance device, detects the relative movement due to conveyance of the recording medium, and generates a pulse signal synchronized therewith. A frequency dividing circuit that divides the pulse signal input from the encoder;
The image recording apparatus according to claim 1, wherein the period measuring unit measures a period of the pulse signal synchronized with the relative movement based on the pulse signal divided by the frequency dividing circuit.   The image recording apparatus according to claim 1, further comprising: an output timing period setting unit that sets a period of the output timing signal based on the multiplied pulse signal, wherein the period of the output timing signal can be changed. .

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