JP2004195785A - Recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder in which a correct driving timing of a recording head can be realized depending on the speed variation of a carriage during acceleration/deceleration. <P>SOLUTION: The recorder comprises a means for predicting the period of a signal being outputted from an encoder, and a means for making a decision whether the predicted period falls within a specified range or not wherein a specified value of period is acquired if the value of the predicted period deviates from the specified range and a recording head is driven by dividing that value equally. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recording device that performs a recording operation using a signal from an encoder.
[0002]
[Prior art]
In the conventional printing apparatus, the cycle of the heat pulse that determines the timing of performing ejection uses the detection interval of the trigger signal one cycle before obtained from the encoder to generate the ejection timing in units of printing resolution. .
[0003]
[Problems to be solved by the invention]
However, if only ink speed fluctuations in the resolution unit are taken into account and ink is ejected at that timing, in printing at high resolution, the deviation in the unit of one block due to the speed fluctuation of the carriage causes the ink landing accuracy When acceleration / deceleration or speed fluctuation is too large, there is a large error between the actual ink ejection timing cycle and the ink ejection timing cycle calculated from the value one cycle before the encoder. Sometimes happened. For example, unevenness occurs in a recorded image.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a recording apparatus that performs recording on recording paper by a recording head by moving a carriage based on a signal of an encoder, and predicts a period of a signal output from the encoder. Predicting means, determining means for determining whether the value of the cycle predicted by the predicting means is within a predetermined range, and acquiring a predetermined value as a value of the cycle if the value of the cycle is outside the predetermined range. An acquisition unit, a division unit for equally dividing the value acquired by the acquisition unit, and a driving unit for driving the recording head based on the value equally divided by the division unit.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram showing a configuration of a main part of a recording apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a recording (printing) head, 2 is a carriage on which a print head is mounted, 3 is a carriage motor for driving the carriage 2, and 4 is a flexible cable connecting the recording head 2 and a head drive control circuit (not shown). is there. Reference numeral 5 denotes a paper feed gear, and reference numeral 6 denotes a paper feed motor that drives a paper feed roller 7 via the paper feed gear 5. 8 is a linear encoder (linear encoder), 9 is an optical sensor for detecting the position of the carriage, and constitutes an optical encoder for detecting the position of the carriage by 8 and 9. P is a recording medium (for example, recording paper).
[0006]
FIG. 2 is a diagram illustrating a configuration of a control unit according to the present embodiment. Reference numeral 11 denotes a host that sends control commands and control data, 12 denotes an interface (I / F) circuit for receiving data transmitted from the host 11, 13 denotes a CPU for controlling the entire apparatus, and 14 denotes required work. A RAM for providing an area and temporarily storing control data and the like input from the host 11 via the interface circuit 12, and a ROM 15 are provided with a program for operating the CPU 13 and a head drive. And a control table for driving the motor and the like are stored in advance.
[0007]
Reference numeral 16 denotes an encoder circuit that detects the position of the carriage based on the output of an encoder sensor 19 that is a carriage position detecting element. Reference numeral 17 denotes a drive circuit for driving the recording head 21 and the head driver 20, and reference numeral 18 denotes a drive circuit for driving the carriage motor 22 and the paper feed motor 23.
[0008]
FIG. 3 is a diagram showing a change in the speed of the carriage during printing (during printing) in the present embodiment. In the high-speed area and the low-speed area, the position detection signal detected by the encoder sensor 19 causes the encoder trigger to change due to the speed change of the carriage. It shows how it is detected. The interval Δd between the encoder triggers is broadly detected when the speed of the carriage is low, and narrowly detected when the speed of the carriage is high.
The speed and position of the carriage are calculated by counting the interval Δd at which the encoder trigger is detected. Details will be described later.
[0009]
FIG. 4 is a timing chart showing the relationship between the heat timing generated based on the encoder trigger which is the position detection signal and the print signal of each block generated based on the heat trigger. The arrangement of the nozzles in the recording head 21 is arranged as shown in this figure. In the present embodiment, it is assumed that the recording head has a total of 120 ink ejection ports (nozzles).
[0010]
In the present embodiment, the 120 ink ejection ports are divided into 24 blocks (1 block = 5 nozzles), and each block is driven to record an image of one vertical column. The arrangement of the nozzles is inclined by an angle θ with respect to the transport direction of the recording head as shown in the figure.
[0011]
FIG. 5 is a diagram showing the timing of the ejection control in this embodiment. Based on the encoder trigger detected by the encoder sensor, the interval is equally divided to generate a heat trigger corresponding to ink ejection in one vertical line of the head.
[0012]
When the heat trigger is input, the head drive circuit sequentially transfers the signals of blocks 1 to 24 to the ink jet recording head 21 to discharge ink in one vertical column of the head. The block trigger which is a signal for driving the block is also generated by equally dividing the heat trigger interval.
[0013]
Here, during the period represented by each signal of the heat trigger of each block and the block trigger from driving the blocks 1 to 24 in the present embodiment, the moving speed of the carriage, the heat cycle, and the ejection of ink for one vertical line are performed. It is obtained from the relationship of the time to do. That is, the head drive circuit 17 measures the interval of the signal input from the encoder circuit 16 using the timer means, and internally calculates the optimal block drive cycle based on the value.
[0014]
The ejection timing of this embodiment controls the ejection timing by equally dividing the time interval of the heat trigger signal generated by the input from the encoder sensor within each heat cycle. Is calculated using the cycle before the position at which is performed.
[0015]
Hereinafter, a method of calculating the heat cycle will be specifically described with reference to FIG. 5. In this figure, the length of the signal being High corresponds to the time actually counted.
[0016]
The encoder trigger is detected according to the speed of the carriage. In the present invention, the period Y at which the encoder trigger is detected is measured using an internal timer means, and the value is stored up to two cycles before. From the variation Δt _{= T x- 2} -T _{x- 1} and the stored two cycles before the value _{T x-2} 1 cycle before the value _{T x-1,} and the predicted heat period Tx performing actual heat The amount of change from the value Tx _-1 one cycle before is also approximated to a change in Δt similarly as shown in FIG. Y1 ′, Y2 ′, and Y3 ′ are determined as T _x−1 + α × Δt. Here, α is a real number that can be arbitrarily set in order to weight the variation Δt. (Because the calculation is performed in the acceleration region, _{Tx− 2} > _{Tx− 1} .)
However, when the next encoder trigger is detected as in the case of Tx = T5 shown in FIG. 5 for the predicted heat cycle, the difference u from the encoder previous cycle and the time when the encoder trigger is detected is stored. The detection time of the encoder trigger is corrected by subtracting the difference u from the next encoder calculation time T6.
[0017]
Here, if the time during which the encoder trigger is detected is extremely short or too long, when the subsequent ink ejection timing is generated, the ink ejection cannot be completed in time or the ink cannot be ejected to a desired position. Or In order to solve this, the encoder calculation time X obtained by subtracting the overtime u from the predicted heat cycle Tx is provided by setting a lower limit value and an upper limit value for comparison with the calculated value.
[0018]
The lower limit and the upper limit are set according to the configuration and specifications of the printing apparatus. That is, as shown in FIG. 5, by comparing the encoder calculation time X, the minimum heat time L corresponding to the lower limit value, and the maximum heat time M corresponding to the upper limit value, the encoder calculation time X is reduced to the minimum heat cycle. When (X <L) is smaller than (lower limit) L, the lower limit L is applied to the actual heat time N.
[0019]
When the encoder calculation time X is longer than the maximum heat cycle (upper limit) M (X> M), the upper limit M is applied to the actual heat time N. That is, the actual heat time N corresponding to the cycle of the heat trigger is determined using the value X that can take a variable value within the range of L <X <M. The heat trigger time is determined by equally dividing the determined actual heat time interval, and the heat trigger time is also equally divided by the heat trigger time, so that the block corresponding to the head drive timing in block units is obtained. Generate a trigger.
[0020]
FIG. 7 shows a flowchart of the above processing. In step S701, it is checked whether an encoder trigger has been detected, and in step S702, a cycle time is checked. Then, in step S3, an encoder cycle is predicted.
[0021]
In step S704, it is checked whether the overtime u is zero. If the overtime is not 0, Tx-u is calculated in step S705.
[0022]
In step S706, it is checked whether the value of Tx-u is larger than the lower limit value. If the value is smaller than the lower limit value L, the lower limit value L is equally divided to generate a heat trigger. In step S707, it is checked whether the value of Tx-u is smaller than the upper limit value, and if larger than the upper limit value M, the upper limit value M is equally divided to generate a heat trigger.
[0023]
Since S <b> 708 is the case where L <Tx−u <M, Tx−u is equally divided to generate a heat trigger.
[0024]
In step S704, it may be checked whether the predicted time> the encoder trigger period, that is, whether the predicted time is over (for example, in the case of T5> Y5 in FIG. 5).
[0025]
In step S702, if the difference between the cycle one cycle before and the cycle two cycles before is larger than the cycle one cycle before, the process proceeds to step S712, and the upper limit M is equally divided to be a heat trigger. This prevents the cycle difference from increasing when the cycle one cycle before is short.
[0026]
With the above configuration, the drive timing of each block can be optimized in real time in accordance with the time interval of the heat trigger, that is, the moving speed of the carriage. Instead, an image can be formed in a state where dots are always aligned in the vertical direction.
[0027]
Further, since the ink ejection cycle is determined by estimating the moving speed of the carriage, it is possible to absorb a certain amount of speed fluctuation. Therefore, for example, it can be used as a recording section even in an acceleration section of the carriage which has not been used conventionally. Further, since the movable range of the carriage can be maximized, the size of the apparatus can be reduced, and the cost can be reduced.
[0028]
Incidentally, in the deceleration section, row the same processes as those in FIG. 7 as a variation Δt _{= T x- 1} -T _{x- 2} of 2 cycles previous value _{T x-2} and the value _{T x-1} of the previous cycle Good.
[0029]
As described above, examples of the embodiments of the present invention are listed below.
[0030]
[Embodiment 1]
A recording device that performs recording on recording paper by a recording head by moving a carriage based on a signal of an encoder, wherein the prediction unit predicts a period of a signal output from the encoder, and the period predicted by the prediction unit. Determining means for determining whether the value is within a predetermined range; obtaining means for obtaining a predetermined value as the value of the cycle if the value of the cycle is outside the predetermined range; and obtaining the value obtained by the obtaining means. [Embodiment 2] The image processing apparatus includes a dividing unit that divides the recording head into equal parts, and a driving unit that drives the recording head based on the values divided by the dividing unit.
If the drive cycle calculation means sets the predicted cycle to Tx, the previous cycle to Tx ₋₁ , the second previous cycle to Tx ₋₂ , and a predetermined value α, Tx = Tx ₋₁ + α (Tx _{x- 2} - _{Tx- 1} ). The recording apparatus according to the first embodiment.
[0031]
[Embodiment 3]
The first embodiment is characterized in that the acquisition unit acquires a first value if the value of the cycle is smaller than a predetermined range, and acquires a second value if the value of the cycle is larger than a predetermined range. Recording device.
[0032]
【The invention's effect】
As described above, according to the present invention, even if the relative speed of the recording head with respect to the recording medium fluctuates to some extent, it is possible to accurately control the printing position by predicting and correcting the fluctuation in advance. It is possible to provide a serial recording device, a serial recording method, and a storage medium in which the accuracy of landing on paper is improved.
[0033]
Further, it can be used as an actual recording section in an acceleration section of the recording head and the like, and it is possible to realize a reduction in size and cost of the apparatus.
[0034]
Furthermore, even if a position detection signal is not detected for some reason, recording can be performed using a preset value, which leads to improvement in reliability of the apparatus.
[Brief description of the drawings]
FIG. 1 is a diagram showing a main mechanism portion of an ink jet recording apparatus. FIG. 2 is a block diagram showing a configuration of a control unit. FIG. 3 is an explanatory diagram of a carriage speed fluctuation in a print area. FIG. FIG. 5 is a diagram showing heat timing calculation. FIG. 6 is a diagram showing a change amount of a heat cycle. FIG. 7 is a flowchart showing a print control process.
(1) Print head (2) Carriage (3) Carriage motor (4) Recording head (5) Paper feed gear (6) Motor to drive paper feed roller (7) Paper feed roller (8) Linear encoder (9) Light Encoder sensor 11 Host 12 Standard I / F circuit 13 CPU
14 RAM
15 ROM
16 Encoder circuit 17 Head drive circuit 18 Motor drive circuit 19 Encoder sensor 20 Head driver 21 Recording head 22 Carriage motor 23 Paper feed motor

Claims (1)

A recording apparatus that performs recording on recording paper by a recording head by moving a carriage based on a signal of an encoder,
Prediction means for predicting the period of the signal output from the encoder,
Determining means for determining whether the value of the cycle predicted by the predicting means is within a predetermined range,
Acquisition means for acquiring a predetermined value as the value of the cycle if the value of the cycle is outside the predetermined range,
Dividing means for equally dividing the value obtained by the obtaining means,
A driving unit for driving the recording head based on the values equally divided by the division unit.

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