JPS63281843A - Method for controlling head of image printing apparatus - Google Patents

Abstract

PURPOSE:To enhance image quality by increasing the expression number of gradations, by driving a blade on the basis of the time width dividing ratio of a fundamental time and scraping off the ink supplied and adhered to a head roller to apply change to an ink adhesion area at every pixel. CONSTITUTION:The pulse width T of the fundamental pulse P1 formed in a pulse generator 13 is determined on the basis of the voltage signal for controlling the fundamental pulse inputted through an F/V converter 12 so as to correspond to the width of the pixel formed to the outer peripheral surface 1a of a transfer roller 1. The ON/OFf ratio in the pulse width of the fundamental pulse P1 is determined on the basis of the ON/OFF ratio control voltage inputted through a D/A converter 16 and, on the basis of the fundamental pulse P2 determined in this ON/OFF ratio, a blade 5 is driven through a voice coil 18 and the ink adhered to the outer peripheral surface 1a is scraped off in accordance with the ON-width T1 of the fundamental pulse P2. An ink adhered part and an ink scraped-off part are generated in the pixel formed to the outer peripheral surface 1a of the transfer roller 1 and the expression of a gradation at every pixel printed on the surface of paper 7 can be attained on the basis of the area ratio of both parts.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an image printing device in which an image is composed of a set of pixels as its minimum unit, and each pixel is recorded and transferred according to image information for each pixel. The present invention relates to a head control method for an image printing apparatus in which gradation is expressed in each pixel by changing the printing area in that pixel.

[Conventional technology]

2. Description of the Related Art Conventionally, a dot matrix method is generally known as a method for forming gradation images in printer technology. In particular, wire dot printers, ink jet printers, etc. basically employ this dot matrix method. This dot matrix method is the 6th
As shown in the figure, one pixel is assumed to be an nxm matrix, and by changing the number of dots D formed in one pixel, the area ratio can be manipulated to achieve shading and gradation expression. It is what you do.

[Problem that the invention seeks to solve]

However, according to such a dot matrix method, it is necessary to provide a large number of output wires and ink jet outlets depending on the matrix, and one
In order to achieve a 100% filled-in area ratio in a pixel, the size of the dot itself had to be changed, and very complicated mechanisms and controls were required.

[Means for solving problems]

The present invention has been made in view of these problems, and is based on the rotational position of the head roller, which is equipped with a blade that scrapes off the ink supplied and deposited on the outer circumferential surface of the head roller. The position of the pixel to be formed on the top is determined, and a basic time is set according to the width of this pixel, and this basic time is divided into time widths according to pixel data predetermined corresponding to the pixel. The ink adhering area of each pixel is changed by driving the blade based on the time width division ratio of the basic time and scraping off the ink supplied and adhering to the head roller.

[Effect]

Therefore, according to the present invention, the ink adhering area in a pixel formed on the outer peripheral surface of the head roller changes based on the basic time division ratio corresponding to the pixel width.

〔Example〕

Hereinafter, a head control method for an image printing apparatus according to the present invention will be explained in detail. FIG. 2 is a side view showing an example of a head section of an image printing apparatus to which this head control method for an image printing apparatus is applied. In the figure, 1 is a transfer roller (head roller), 2 is an auxiliary roller that rotates in contact with this transfer roller l, 3 is an ink supply roller that rotates in contact with this auxiliary roller 2, and 4 is an ink supply roller 3. This is the ink supplied. That is, the supplied ink 4 is supplied to the outer peripheral surface 1a of the transfer roller 1 via the ink supply roller 3 and the auxiliary roller 2, and the supplied ink 4 is supplied to the outer peripheral surface 1a' of the transfer roller 1. The ink 4a is scraped off using the blade 5 when the actuator 6 is turned on. That is, the tip end surface of the blade 5 comes into contact with the outer circumferential surface 1a of the transfer roller 1 by turning on the actuator 6, and the supplied ink 4a is scraped off by the tip end surface of the blade 5 in contact with the outer circumferential surface 1a. In the same figure, 7 is the paper surface to which the pixels formed on the outer peripheral surface la of the transfer roller 1 are to be transferred;
10 is a drain receiver for the ink scraped off by the blade 5; 9 is a cleaning blade for scraping the ink remaining on the outer peripheral surface 1a after being transferred to the paper surface 7; and 10 is a drain receiver for the ink scraped by the cleaning blade 9. .

FIG. 1 is a block configuration diagram showing an example of a drive control circuit for the actuator 6 in the head of the image printing apparatus configured as described above. In the figure, 11 is a rotary encoder that sends out a number of pulse signals corresponding to the amount of rotation of the transfer roller 1 as the transfer roller 1 rotates, and 12 is a pulse signal sent out by the rotary encoder 11 (rotary x y: + The frequency of this pulse signal is F/V converted and the voltage value corresponding to the frequency is sent to the pulse generator 13 as a basic pulse control voltage signal. converter, 1
4 inputs the pulse signal sent by the rotary encoder 11, and detects the mechanical position (rotational angular position) of the transfer roller 1 based on this pulse signal, and also detects the outer circumference of the transfer roller 1 based on this mechanical position. The position of a pixel to be formed on the surface 1a is determined by pulse counting, and the timing of extracting gradation data (pixel data) stored in advance corresponding to this pixel from the RAM 15, and the D/A converter of this gradation data. This is a control device that controls the sending timing to 16.

In the pulse generator 13, based on the basic pulse control voltage signal inputted through the F/■ converter 12, the width of the basic pulse generated therein is determined based on the width of the basic pulse to be formed on the outer circumferential surface 1a of the transfer roller 1. The width of the pixel (the length of the transfer roller l in the circumferential direction) is controlled in accordance with the width of the pixel (the length of the transfer roller l in the circumferential direction). The on/off ratio (division ratio) within the pulse width of the basic pulse in this pulse generator 13 is controlled based on the voltage signal input via the D/A converter 16. That is, the D/A converter 16 sends an on/off ratio control voltage determined by the gray scale data delivered via the control device 14 to the pulse generator 13, and Based on this, the on/off ratio within the pulse width of the basic pulse in the pulse generator 13 is determined, and this on/off ratio is determined.
The basic pulse whose off-ratio has been determined is sent to the amplifier 17. Then, after this basic pulse with the determined on/off ratio within the pulse width is amplified to a value sufficient for driving it in the amplifier 17, the voice coil 18
The blade 5 is driven via the actuator 6 by turning the voice coil 18 on and off based on this basic pulse. That is, when the voice coil 18 is turned on, the tip end surface of the blade 5 comes into contact with the outer peripheral surface 1a of the transfer roller 1, and the supplied ink 4a is scraped off.

FIG. 3(a) shows a basic pulse generated inside the pulse generator 13, and the pulse width T of this basic pulse P1 is the basic pulse control voltage signal input via the F/v converter 12. Based on transfer roller 1
The pixel width is determined corresponding to the pixel width to be formed on the outer circumferential surface 1a. Then, the on/off ratio within the pulse width of this basic pulse P1 is determined based on the on/off ratio control voltage input via the D/A converter 16, as shown in FIG. The blade 5 is driven via the voice coil 18 based on the basic pulse P2 having a predetermined on-off ratio (on width, T2: off width). That is, in the ON width T1 of this basic pulse P2, the tip surface of the blade 5 is driven so as to be in contact with the outer circumferential surface 1a of the transfer roller 1, and the adhering ink 4a on the outer circumferential surface la is
is scraped off, and the scraping operation is stopped at the off width T2. In this way, the outer peripheral surface 1 of the transfer roller 1
In the pixel formed in the area a, there are areas where the ink is attached and areas where the ink is scraped off, and the ratio of these areas makes it possible to express the gradation of each pixel printed on the paper surface 7.

As described above, according to the head control method of the image printing apparatus according to the present embodiment, the pixel position is determined from the mechanical position of the transfer roller 1 detected using the rotary encoder 11, so that the pixel position accuracy is high. , and since the on/off ratio within the pulse width of the basic pulse can be varied,
This has the excellent effect that the print area change in a pixel can be controlled from 0 to 100%, and the number of gradation expressions can be increased. In other words, it is possible to express an image with less distortion due to improved image position accuracy, and since tone expression is performed using the on/off ratio within the pulse width of the basic pulse, ink scraping work that is faithful to the Wt tone data can be performed. , a clear image can be expressed, and the image quality can be improved by increasing the number of gradation expressions. Furthermore, it has many advantages over the conventional dot matrix method, such as simpler mechanical structure and control.

In this embodiment, the basic pulse control voltage signal and the on/off ratio control voltage signal are input to the pulse generator 13 via the F/V converter 12 and the D/A converter 16. On/off within the pulse width of the basic pulse sent from the pulse generator 13
Although the off-ratio is changed, even with a circuit configuration using a counter and flip-flop as shown in Fig. 4,
The on/off ratio within the pulse width of the basic pulse can be varied according to the gradation data. That is, if the total number of gradations is set as a counter value in the counter 19, and the pulses generated at a period obtained by dividing the pixel formation time by the total number of gradations are inputted to the counter 19 as count pulses, the transfer roller 1 From the time of input of the count start signal (pixel timing signal) that is input based on the mechanical position of (Fig. 5 (
At point a in a), a countdown is started based on the count pulse, and when the total number of gradations is counted and reaches zero, the counter 19 sends out a zero pulse (see Fig. 5).
Point b in a), and also set a counter value (gradation data) in the counter 20 according to the pixel data of each pixel,
If the above-mentioned count start signal and count pulse are input in the same way as the counter 19, a countdown based on the count pulse will be started, and when the set number of gradations is counted and the count reaches zero, the counter 20 will send out a zero pulse (the 0 point in Figure 5 (1))). That is, at the time when the counter 20 sends out the zero pulse, the flip-flop 2
1, and reset the flip-flop 21 at the time when the counter 19 sends out the zero pulse, it is possible to obtain the flip-flop output as shown in FIG. Based on the zero pulse sent out by the flip-flop 20, the time from the input of the pixel timing signal to the time the counter 19 sends out the zero pulse is defined as a basic time, and the time width ratio (division) of the rHJ and rLJ levels of the flip-flop output of the flip-flop 21 within this basic time ratio) is variable.

〔Effect of the invention〕

As explained above, according to the head control method for an image printing apparatus according to the present invention, the head roller is controlled based on the rotational position of the head roller, which is equipped with a blade that scrapes off ink that has been supplied onto the outer peripheral surface of the head roller. The position of a pixel to be formed on the outer peripheral surface is determined, a basic time is set according to the width of this pixel, and this basic time is divided into time widths according to pixel data predetermined corresponding to the pixel. By driving the blade based on the time width division ratio of this basic time and scraping off the ink supplied and adhered to the head roller, the ink adhesion area for each pixel is changed, so that the outer periphery of the head roller The ink adhesion area in a pixel formed on a surface changes based on the basic time division ratio according to the pixel width, making it possible to vary the print area change in a pixel from 0 to 100%. Compared to the dot matrix method, its mechanical structure and control are simpler, and the number of gradation expressions can be increased to improve image quality, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing an actuator drive control circuit showing an embodiment of the head control method for an image printing apparatus according to the present invention, and FIG. 2 is an image printing result obtained by applying the head control method for the image printing apparatus. A side view showing an example of the head section of the device, FIG. 3 is a diagram showing basic pulses in the pulse generator in the actuator drive control circuit shown in FIG. 1, and FIG. FIG. 5 is a time chart illustrating the operation of this actuator drive control circuit, and FIG. 6 is a diagram illustrating gradation expression using the conventional dot matrix method. DESCRIPTION OF SYMBOLS 1... Transfer roller, 1a... Outer peripheral surface, 4a... Supply adhering ink, 5... Blade, 6... Actuator, 11... Rotary encoder, 12... F/
V converter, 13...Pulse generator, 14...Control Wi! , 15...RAM, 16...D/
A converter.

Claims (1)

[Claims] Based on the rotational position of the head roller, which is equipped with a blade that scrapes off the ink that has been supplied onto the outer circumferential surface of the head roller,
The position of a pixel formed on the outer peripheral surface of the head roller is determined, and a basic time is set according to the width of this pixel, and this basic time is a time according to pixel data predetermined corresponding to the pixel. By dividing the ink into widths and driving the blade based on the time width division ratio of this basic time to scrape off the ink supplied and adhered to the head roller,
A head control method for an image printing apparatus that changes the ink adhesion area for each pixel.