JPH0444857A - Ink jet printer - Google Patents

Abstract

PURPOSE:To carry out precise printing by imparting objective deflecting quantity to an objec tive ink droplet by storing the dot data showing the objective deflecting quantity of the objective ink droplet to be charged and also storing the presence of charge to an ink droplet to be made the same as the objective ink droplet in the objective deflecting quantity to set the charging quantity of the objective ink droplet on the basis of the dot data and the presence of the charge of the ink droplet. CONSTITUTION:The ink droplets (a), (b) of the second row strongly receive the effect of air resistance because there is no ink droplet in the forward direction to become a tendency to lower in flying speed and to increase in deflection quantity. Therefore, when no air resis tance is considered, the ink droplets (a), (b) adhere to a position slightly higher than a refer ence position and a character '1' is distorted. In the ink droplet row of the first row being the front row of the ink droplet (b), it is judged whether the ink droplet (x) same as the objective ink droplet (b) in objective deflecting quantity, the ink droplet (z) before the ink droplet (x) by one and the ink droplet (y) after the ink droplet (x) by one are formed on an object 40 to be printed as dots and the judgement result is outputted to a charging electrode and the objective ink droplet is charged so as to have charge quantity of a proper value. Since a video signal containing strain correction data is low as compared with one not consid ering air resistance, the deflecting quantity of the objective ink droplet (b) is reduced and the objective deflecting quantity is obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an inkjet printer that performs printing by charging a plurality of ink droplets and controlling their deflection to form a desired dot matrix on a printing substrate. .

[Conventional technology]

As a conventional ink jet printer, for example, there is one described in Japanese Patent Publication No. 60-27576.

This inkjet printer divides multiple ink droplets that are located relatively far away from the target ink droplets that are about to be charged into multiple groups, and then calculates the target ink droplets by taking into account the effects of air resistance on each group on the target ink droplets. This is to correct the amount of charge on the droplet, etc.

[Problems to be Solved by the Invention] However, in such conventional inkjet printers, it is not possible to accurately identify ink droplets that have an effect of air resistance on the target ink droplets, so it is difficult to determine whether the target ink droplets are deflected by the target amount of deflection. However, there is a problem in that precise printing may not be possible.

The present invention has been made by focusing on such conventional problems, and it accurately grasps the ink droplets that have an effect of air resistance on the target ink droplets, and based on this, determines the amount of deflection of the target ink droplets. It is an object of the present invention to provide an inkjet printer that can obtain a target amount of deflection of a target ink droplet by correcting the amount of deflection of the target ink droplet, and can perform precise printing.

[Means for Solving Problem 1] An inkjet printer for achieving the above purpose is:
In an inkjet printer that charges multiple ink droplets and then controls their deflection to form a desired dot matrix on a printing substrate, dot data that indicates the target deflection amount of the target ink droplets to be charged. a dot data storage means for storing at least one of the plurality of ink droplets forming the previous row of ink droplets for an ink droplet row forming one of the plurality of rows of the dot matrix and including the target ink droplet; a front row charge storage means for storing the presence or absence of charge on the ink droplet to make the target ink droplet and the target deflection amount the same; the dot data; and the charge of the front row ink droplet stored in the front row charge storage means; The present invention is characterized by having a charge amount setting means for setting the charge amount of the target ink droplet based on the presence or absence of the target ink droplet.

[Operation] When a target ink droplet is charged with a placement electrode, the amount of charge of the target ink droplet is determined based on the dot data indicating the target deflection amount of the target ink droplet and the plurality of ink droplets forming the front row of ink droplets. It is set based on whether or not an ink droplet among the ink droplets that should have the same target deflection amount as at least the target ink droplet is charged.

Generally, ink droplets ejected from a nozzle are subjected to air resistance during flight until they reach the printing substrate. What is the effect of this air resistance on the target ink droplet?

Among the plurality of ink droplets forming the front row of ink droplets, an ink droplet that should have the same target deflection amount as the target ink droplet and a plurality of ink droplets before and after the target ink droplet are located in front of the target ink droplet. It really depends on whether you're flying or not.

Therefore, among the plurality of ink droplets forming the ink droplet row in the front row, whether the ink droplet that should have the same target deflection amount as the target ink droplet and the plurality of ink droplets before and after the ink droplet are charged. No 2 In other words, by determining whether or not the target ink droplet is flying in front of the target ink droplet and setting the amount of charge on the target ink droplet, the target ink droplet can obtain the target amount of deflection. Precise printing can be performed.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 9.

The inkjet printer of this embodiment performs printing by charging a plurality of ink droplets and controlling their deflection to form a desired dot matrix on a substrate. As shown in FIG. 1, M Pul is a microcomputer that controls the entire circuit within the inkjet printer. ROM2 is a storage element that stores programs and fixed data necessary for M P u 1 to operate.

The RAM 3 is a rewritable storage element that temporarily stores data and the like required for program progression. The pass line 4 receives data signals from MPul, address signals,
and control signals, a signal line that includes everything. The FiFO 5 is a first-in/first-out register, and the M P u 1 outputs dot matrix data in units of 1 byte to this FiFO 5. Fi
The output of FO5 is guided to register A6 and selector C8.

Register A6 and register B7 are for storing dot data of one row before the target ink droplet to be charged. The selector C8 is for converting the 8-bit parallel output of the FiFO 5 into a serial signal. Selector A9 and selector BIO convert the output signals of register A6 and register B7, respectively, into serial signals.

PiAll is a peripheral interface adapter that inputs and outputs signals.The input signal includes a printing material detection signal from the sensor 39 that detects the presence or absence of the printing material 40. Further, the output signals include a clear signal for clearing the contents of register A6 and register B7, a matrix switching signal for changing the dot matrix format, and a print start signal indicating the start of printing.

Various control information is written in advance in the control RAM 13 so that printing control can be executed according to the procedure. The buffer A12 has the function of outputting the data signal in the A port path line 4 to the control RA and M13, and outputting the data signal of the control RA and M13 to the A port path line 4, thereby determining the direction in which data flows. There is. Selector E14 is the control RA, M1
This is for switching the address information of No. 3. The thinning switch 15 is for setting the utilization rate of ink droplets. The excitation setting switch 16 is for setting the frequency of the excitation signal given to the nozzle 32. The frequency division counter 17 outputs a signal from the oscillator 18 to a thinning switch 15,
Divide the frequency based on the excitation setting switch 16 and set the required OT.
l, ○Create T2 signal. The staircase wave counter 19 repeatedly outputs a staircase wave, with one column of printing as one cycle. Buffer B20 is used for data input/output to video RAM21. The video RAM 21 stores distortion-corrected staircase wave data.

The shift register B24 shifts the dot data of the ink droplet array including the target ink droplet output from the selector C8 by 3 bits and then outputs the data. Gate A2
5. N gate 26, gate B27, and O gate 28 are matrix switching circuits for selecting which of the outputs of selector A9 and selector BIO is to be used.

The shift register A23 transfers the dot data of the ink droplet column one column before the target ink droplet to terminals QB, QC1, and Q.
It is output from D. The dot data output from the terminal QC is shifted by 1 bit with respect to the dot data output from the terminal QB, and the dot data output from the terminal QD is shifted by 2 bits with respect to the dot data output from the terminal QB. Bit shifted and output.

The selector F22 is for switching address lines. A gate C29 is an A, ND gate related to video signal creation. Note that there is only one A gate C29 in Figure 1, but this is a simplified drawing, and in reality,
Since the video signal from the video RAM 21 is a 12-bit digital signal, 12 are provided.

The D/A converter 30 is for converting a digital video signal into an analog signal.

This output is guided to the subsequent stage AMP 31 and amplified there. The nozzle 32 is used to turn the ink into particles, and the charging electrodes 33 charge the ink particles. Deflection electrode +3
4. The deflection electrode 35 and the high voltage power supply 36 form a deflection electrostatic field to deflect the ink droplet 37 ejected from the nozzle 32. The gutter 38 is used to collect unused ink.

Having described the overall configuration above, the operation of the present invention will now be described.

It is necessary to make the settings in advance before starting the printing operation. This presetting will be explained based on FIG. 2.

First, it is determined whether there is a dot matrix switch for printing (step 1). This judgment is made in advance by entering the cover panel 4.
This is performed based on the data input from 1 and stored in the temporary storage area of the RAM 3. If there is dot matrix switching, dot matrix switching processing is performed (step 2) and then the process proceeds to step 3; if there is no dot matrix switching, the process immediately proceeds to step 3.

The dot matrix switching process is performed using PiAll's ○T2.
This is done by the matrix switching signal from . If the matrix of characters to be printed is 8 vertical dots or less, this signal is set to "1", and if the matrix is 9 to 16 vertical dots, this signal is preset to 110 II. In this embodiment, the number of vertical dots can be set up to 16, but it is clear that by adding similar circuits after register B7 and after selector BIO, it is possible to handle more than 16 vertical dots. Hereinafter, this embodiment will be explained using seven vertical dots.

In step 3, it is determined whether the contents of the video RAM 21 have been changed. This determination is also made based on data input in advance from the input panel 4 and stored in the temporary storage area of the RAM 3.

If there is a change in the contents of the video RAM 21, buffer B
20 and the A boat of selector F22, a staircase wave including distortion correction information is written in advance (step 4). If the character height, dot matrix, etc. are constant and do not change, the video RAM 21 can be replaced by a ROM (read only memory) that cannot be rewritten.

As shown in FIG. 3, the address information of the video RAM 21 includes a total of 9 bits of information.

Of these, 6 bits 2e to 25 are used to advance the steps of the staircase wave, and 3 bits 26 to 28 are used to express the presence or absence of a dot in the front row of the ink droplet row containing the target ink droplet. . Note that the 27 bits indicate the presence or absence of a dot formed by an ink droplet with the same target deflection amount as the target ink droplet.

The 21 bit indicates the presence or absence of a dot formed by an ink droplet that is one ink droplet after the target ink droplet and the same target deflection amount, and the 2s bit indicates the presence or absence of an ink droplet that is formed by the ink droplet that has the same target deflection amount as the target ink droplet. It expresses the presence or absence of a dot formed by the previous ink droplet. Information on whether or not the three ink droplets in the front row are charged can be expressed using three bits.

There are eight types of combinations in total, and for all these combinations, staircase waves containing distortion correction information are created in advance and stored in the video RAM 21.

The staircase wave containing distortion correction information is actually the voltage of the video signal output from the AMP 3 to the charged electrode 33. When the voltage without considering air resistance is En (the symbol n attached to V and E indicates how many steps from the bottom of the waves forming the staircase wave),
It is created so that a video signal voltage vn as shown in FIG. 9 can be obtained.

Specifically, among the outputs from terminal QB, terminal Q, and C1 terminal QD of shift register A23, which indicate the presence/absence of dots in the front row, when the output of terminal QB is "0", that is, when the output of the ink droplets in the front row is When there is no dot formed by an ink droplet that is one ink droplet after the target ink droplet and the same target deflection amount.

It is created so that the video signal voltage V is obtained by subtracting El and +1/α from En. Also, terminal Q
When the output of C is II O71, that is, when there is no ink droplet in the front row that is formed by an ink droplet with the same target deflection amount as the target ink droplet, the change from En to En/
The value obtained by subtracting β is the video signal voltage ■. When the output of the terminal QD is II O'', that is, the target ink droplet is formed by the ink droplet that precedes the target ink droplet and the target ink droplet with the same target deflection amount among the ink droplets in the front row. When there is no dot, the video signal voltage vn is obtained by subtracting En-, . . . /γ from -En.

In this example, E''-11E n+ is used, but
It is also possible to substitute this value with En and set α, β, and γ.

It is assumed that the data to be printed is input into the RAM 3 in advance using the input panel 41 or the like.

In step 5, it is determined whether or not the contents of the control RAM 13 need to be changed. If the contents need to be changed, the contents of the control RAM 13 are changed (step 6). Content changes are carried out by providing write data to the controls R and AM13 via the buffer A12. Note that the address at this time is given to the control RAM 13 from the A port of the sector E14 via the Y port.

As shown in FIG. 6, the data in the control RAM 13 is formed of 8-bit data from 2° to 27, and the 3 bits from 2° to 22 are data select signals. This data select signal is supplied to selector A9, selector BIO, and selector c8, respectively, and causes selector A9, selector BIO, and selector C8 to extract one specific bit from among the 8-bit input data input here. This is to make eight numbers from the Y@ child of selector A9, selector BIO, and selector C8. The data select signal is output as shown in FIG.

Also, of the data in the control RAM 13, 23
The bit is a valid dot signal indicating that it is an ink droplet used for printing, and is an input signal to the A gate C29. In addition, 24 bits is a data read signal that is output to the R terminal of FiFo5, the CK terminal of register A6, and the CK terminal of register B7, and is used to sequentially read data in 1-byte units from FiFo5, register A6, and register B7. It is something. Note that bits 25 to 27 are not used in this embodiment.

Next, the printing operation of the present invention will be explained using FIGS. 7 and 8.

When the printing material 40 is transported by a conveyor (not shown) or the like and detected by the sensor 39, a printing material detection signal is output from the sensor 39 to the iN1 terminal of PiAll, as shown in FIG. 8(A). With this signal, M, P u
An interrupt occurs in M P u 1, and Pi
A clear signal is output to register 86 and register B7 (step 1o), and a print start signal is output to step wave counter 19 and A gate C29 (step 11).

Then, the MPu 1 searches for a character code to be printed (step 12), and outputs dot data corresponding to the character code to the FiFO 5 (step 13). The operation of steps 12 and 13 is M P u 1
is repeated until there is no more data to be printed (step 14).

The dot data input to F1FO5 is shown in Figure 8 (a).
As shown in the figure, an 8-bit parallel signal appears from terminal Q. At this time, as shown in FIG.
6) is input to the A-C terminal of the selector c8, and the dot data from the FiF5 is sequentially converted into a serial signal by the selector c8.

The dot data converted into a serial signal is inputted to the terminal S1 of the shift register B24, and then transferred from the staircase wave counter 1-9 to the shift register B as shown in FIG. 8(A).
2. In synchronization with the clock signal input to terminal CK of 4,
State 1 of 3-bit shift to 1 as shown in Figure 8 (1)
- Output. When all the data in the 1st] column is taken into shift register B2J, F ],, F O5
end fR, -1 terminal of nozzle A6 ~ CK, and L/
A pulse signal as shown in Figure 81 (E) is input to terminal CK of register 7, 1-byte dot data of FiF○5 is transferred to register 86, and from terminal Q of 1-no register A6, the pulse signal shown in Figure 8 (Power) is input. ), the dot data in the first column is output. At the same time, as shown in FIG. 8(a), the second column of dot data is output from the FiF 5.

The dot data in the first column from register 80 is h1j
In synchronization with the clock signal input from the above-mentioned staircase wave counter] 9 to the terminal CK of the shift register A23, the end FQB, as shown in FIGS.
3 bits are retrieved from terminal QC1 terminal QI) and output to selector p22.
2, Gino l-1/Gister A 2.3 (7) End %Q
B, end F-Q C OJ, end-i' Q I) F1]
(7) First column dot data and staircase wave counter 19
From σ] 2nd row staircase wave and 4, bidet 71” RAM
2.], and output the address information.

The video RAM, 2] uses the staircase wave including the distortion correction information corresponding to this address information as the second column [8+ video signal], and sends it through the A gates C2, 9, the D/A converter 30, and the AMP 31. , is output to the charged electrode 33 as shown in FIG. The first charging electrode 33 charges the ink droplets in the second row with a voltage corresponding to the voltage of this video (%).The ink droplets are deflected by the deflection electrodes 34 and 35 according to the amount of charge. , adheres to the printing substrate 40.

This state will be explained using FIGS. 4 and 5. Here, a case will be specifically described in which the characters ll l II are printed.

As shown in Figure 5, ink droplets a and ink droplets in the second row are strongly affected by air resistance because there are no ink droplets in front of them, and their flight speed tends to decrease and the amount of deflection increases. There is. Therefore, if air resistance is not considered, the fourth
As shown in figure (a), when an ink drop d is dropped,
It adheres to the area a little above the base position by 2 degrees and ends up forming u 1. The letter II is distorted.

By the way, in the Infusiera 1-printer of this embodiment, when the target ink droplet is ink, ltf b, the sentence 1-(>
When reproduced, an ink droplet x with the same deflection amount as a target, an ink droplet 7 before the ink droplet X, and an ink My one after the ink droplet X will form a dot on the printing substrate 40. I, formed 1st. (K).

This information is stored at terminals QB and Q of jit register A23.
C, tl is obtained by the output from the termination terminal.

In this case, the ink droplet XH3'gZ is not formed as one head, so the ink droplet
1 terminal Q I), respectively 0" 11011 11
011 is output, and a video signal corresponding to this output is output from the video RAM 2.1. Come on.

The video signal, which is amplified by the AMP31 and has the voltage shown in FIG.
γ)? This is output to the FF electrode 33, and the target ink droplet is charged to an appropriate amount of charge. Video signal voltage V.

is comparatively lower than that without consideration of air resistance, so the amount of deflection of the target ink droplet l) becomes small, and the target deflection j is obtained.

Similarly, for the charge of the ink droplets a, C+ d, forming the substrate 401, '01-soto, but the video RAM
2] Distortion compensation in ``■'' Video number a containing E information is used.

Therefore, as shown in FIG. 4(a), the letters II] and u are obtained with almost no distortion.

In this embodiment, even if the utilization rate of ink droplets is changed by the thinning switch 15, P1. According to A11,
Even if the dot matrix is changed, characters with almost no distortion can be obtained in the same way by changing various setting values during presetting.

In this embodiment, among the ink droplets in the front row, the ink droplet having the same target deflection amount as the target ink droplet and the ink droplet immediately before the ink droplet having the same target deflection amount as the target ink droplet. This takes into consideration the influence of air resistance caused by the droplet and the ink droplet one ink droplet after the target ink droplet with the same target deflection amount, but in addition to these ink droplets, the target ink droplet Also consider the influence of air resistance caused by the ink droplet two ink droplets before the target ink droplet with the same target deflection amount, and the ink droplet two ink droplets after the target ink droplet with the same target deflection amount. You can do it like this.

[Effects of the Invention] According to the present invention, among the plurality of ink droplets forming the ink droplet row in the previous row, at least an ink whose target deflection amount is the same as that of the target ink droplet is selected. It determines whether the droplet is electrically charged, that is, whether it is flying in front of the target ink droplet, and then sets the amount of charge on the target ink droplet by taking into account the air resistance of the target ink droplet. The target ink droplet can be deflected to a target amount, and precise printing can be performed.

[Brief explanation of drawings]

Figure 1 is an overall circuit diagram of an inkjet printer. Figure 2 is a flowchart of the presetting process, Figure 3 is an explanatory diagram showing the address of the video RAM, Figure 4 is an explanatory diagram showing the state in which the character '1'' is drawn on the printing material, and Figure 5 is an explanatory diagram showing the ink Fig. 6 is an explanatory diagram showing the flight state of the droplets, Fig. 6 is an explanatory diagram showing data in the control RAM, Fig. 7 is a flowchart of the printing process, Fig. 8 is a waveform diagram of signals output from various circuits, and Fig. 9 is an explanatory diagram showing the data of the control RAM. It is an explanatory diagram showing voltage of a video signal. 1-MPu, 5 = F i F o, 6...Register A, 7... Register B, 9... Selector A, 11
...PiA, 13...Control RAM, 15...
Thinning switch, 19... Staircase wave counter, 21...
Video RA, M. 22... Selector F, 23... Shift register A, 2
4...Shift register B, 29...A gate C13
1... A MP, 32... Nozzle, 33... Charging electrode, 34.35... Deflection electrode, 40... Printing material. Figure 3 The bits in Figures 26 to 2B are dots zero and zero.

Claims (1)

[Claims] 1. In an inkjet printer that performs printing by charging a plurality of ink droplets and then controlling deflection to form a desired dot matrix on a printing substrate, the target of the target ink droplet to be charged is a dot data storage means for storing dot data indicating an amount of deflection to be determined; and a plurality of ink droplet arrays forming a preceding row of ink droplets with respect to an ink droplet row forming one of the plurality of rows of the dot matrix and containing the target ink droplet. a front row charge storage means for storing the presence or absence of a charge on an ink droplet that should have the same target deflection amount as at least the target ink droplet among the ink droplets; 1. An inkjet printer comprising a charge amount setting means for setting a charge amount of a target ink droplet based on whether or not an ink droplet in a front row is charged. 2. The front row charge storage means stores the presence or absence of charge on an ink droplet that should have the same target deflection amount as the target ink droplet, and the presence or absence of charge on a plurality of ink droplets before and after the ink droplet. The inkjet printer according to claim 1, characterized in that: 3. In an inkjet printer that prints by controlling deflection after charging multiple ink droplets to form a desired dot matrix on the printing substrate, it indicates the target deflection amount of the target ink droplets to be charged. a register for storing first data; and at least one of a plurality of ink droplets forming a previous column of ink droplets for an ink droplet column forming one of the plurality of columns of the dot matrix and including the target ink droplet. a second register that stores second data indicating whether or not an ink droplet that should have the same target deflection amount as the target ink droplet is charged; and a second register that stores the first data and the second data as an address. As information, for each ink droplet with a different target deflection amount, among the plurality of ink droplets forming the ink droplet row in front of the ink droplet, at least the target ink droplet and the target deflection amount should be the same. The ink droplet is characterized by comprising: a memory that stores a charge amount setting value depending on whether or not an ink droplet is charged; and an amplifier that amplifies the output of the memory and then outputs the amplified output to a deflection electrode that charges the target ink droplet. Inkjet printer.