JPH0825319B2 - Head control method for image printing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is an image printing apparatus in which an image is composed of a set of pixels, which is the minimum unit, and each pixel is recorded and transferred in accordance with image information of each pixel. In the above, the present invention relates to a head control method for an image printing apparatus, which performs gradation expression in each pixel by changing a printing area in the pixel.

[Conventional technology]

Conventionally, a dot matrix method is generally known as a method of forming gradation pixels in printer technology. In particular, this dot matrix method is basically adopted in wire dot printers, ink jet printers and the like. The dot matrix method is the sixth
As shown in the figure, it is assumed that one pixel is an n × m matrix, and the area ratio is manipulated by changing the number of dots D formed in this one pixel to realize gradation, and to express gradation. It is possible.

[Problems to be solved by the invention]

However, according to such a dot matrix method, it is necessary to provide many output wires and ink jet outlets according to the matrix,
In order to make 100% filled area ratio in one pixel, it is necessary to change the size of the dot itself, which requires a very complicated mechanism and control.

[Means for solving problems]

The present invention has been made in view of such problems,
Based on the rotational position of the head roller provided with a blade for scraping the ink supplied and adhered onto the outer peripheral surface, the pixel position to be formed on the outer peripheral surface of the head roller is determined and the pixel position is preliminarily corresponding to this pixel position. By driving the blade based on the determined pixel data and scraping off the ink adhering to the head roller, the ink adhering area for each pixel is changed.

[Action]

Therefore, according to the present invention, the ink adhesion area in the pixel formed on the outer peripheral surface of the head roller changes based on the pixel position.

〔Example〕

Hereinafter, the head control method of the image printing apparatus according to the present invention will be described in detail. FIG. 2 is a side view showing an example of a head portion of an image printing device to which the head control method of the image printing device is applied. In the figure, 1 is a transfer roller (head roller), 2 is an auxiliary roller that rotates in contact with the transfer roller 1, 3 is an ink supply roller that rotates in contact with this auxiliary roller 2, and 4 is an ink supply roller 3. It is a supply ink of. That is, the supplied ink 4 is adapted to be supplied and adhered to the outer peripheral surface 1a of the transfer roller 1 via the ink supply roller 3 and the auxiliary roller 2, and the ink 4a supplied and adhered to the outer peripheral surface 1a of the transfer roller 1. However, when the actuator 6 is driven on, the blade 5 is used for scraping. That is, the tip end surface of the blade 5 comes into contact with the outer peripheral surface 1a of the transfer roller 1 when the actuator 6 is driven on, and the supplied adhering ink 4a is scraped off by the tip end surface of the blade 5 in contact with the outer peripheral surface 1a. In the figure, 7 is the outer peripheral surface 1a of the transfer roller 1.
The paper surface on which the pixels formed are to be transferred, 8 is a drain receiver for the ink scraped off by the blade 5, 9 is a cleaning blade for scraping off the ink remaining on the outer peripheral surface 1a after the transfer to the paper surface 7, 10 is this This is a drain receiver for the ink scraped off by the cleaning blade 9.

FIG. 1 is a block diagram showing an example of a drive control circuit for the actuator 6 in the head of the image printing apparatus having such a configuration. In the figure, 11 is a rotary encoder that sends out a number of pulse signals according to the rotation amount of the transfer roller 1 according to the rotation of the transfer roller 1, and 12 is a pulse signal (rotary encoder pulse) sent out by the rotary encoder 11. The pulse generator 13 converts the frequency of this pulse signal to F / V and uses the voltage value according to the frequency as the basic pulse control voltage signal.
The F / V converter, 14 for sending to the rotary encoder 11 receives the pulse signal sent from the rotary encoder 11, detects the mechanical position (rotational angle position) of the transfer roller 1 based on this pulse signal, and The pixel position to be formed on the outer peripheral surface 1a of the transfer roller 1 is pulse-counted and calculated based on the target position, and the gradation data (pixel data) stored in advance corresponding to this pixel is extracted from the RAM 15 at the timing. And this gradation data D / A converter 1
It is a control device that makes the timing of sending to 6.

In the pulse generator 13, the width of the basic pulse generated inside based on the basic pulse control voltage signal input via the F / V converter 12 is to be formed on the outer peripheral surface 1a of the transfer roller 1. The width of each pixel (the length in the circumferential direction of the transfer roller 1) is controlled correspondingly. And this pulse generator 13
The ON / OFF ratio (division ratio) within the pulse width of the basic pulse at is controlled based on the voltage signal input via the D / A converter 16. That is, the D / A converter 16 does not send the on / off ratio control voltage determined by the grayscale data transferred via the control device 14 to the pulse generator 13, and the on / off ratio control voltage is set to this on / off ratio control voltage. Based on the pulse width of the basic pulse in the pulse generator 13,
The off-ratio is determined, and the basic pulse with the determined on-off ratio is sent to the amplifier 17. Then, the basic pulse whose on / off ratio is determined within the pulse width is input to the voice coil 18 after being amplified by the amplifier 17 to a value sufficient for driving the basic pulse. Based on voice coil 18
The blade 5 is turned off through the actuator 6
Are being driven. That is, the voice coil 18
When the drive is turned on, the tip surface of the blade 5 comes into contact with the outer peripheral surface 1a of the transfer roller 1 so that the supplied and adhered ink 4a is scraped off.

FIG. 3A shows a basic pulse generated inside the pulse generator 13, and the pulse width T of the basic pulse P1 is a voltage signal for basic pulse control input via the F / V converter 12. Based on the above, it is determined corresponding to the pixel width to be formed on the outer peripheral surface 1a of the transfer roller 1.
Then, the on / off ratio within the pulse width of the basic pulse P1 is determined based on the on / off ratio control voltage input through the D / A converter 16 as shown in FIG. : ON width, T2: OFF width), this ON
The blade 5 is driven via the voice coil 18 on the basis of the basic pulse P2 having the determined off ratio. That is, at the ON width T1 of this basic pulse P2, the tip end surface of the blade 5 is driven so as to contact the outer peripheral surface 1a of the transfer roller 1, the adhered ink 4a on the outer peripheral surface 1a is scraped off, and at the OFF width T2, The scraping work is suspended. In this way, a portion where ink is adhered and a portion where the ink is scraped off are generated in the pixel formed on the outer peripheral surface 1a of the transfer roller 1, and the gradation of each pixel printed on the paper surface 7 is caused by the area ratio of these. Can be expressed.

As described above, according to the head control method for the image printing apparatus of the present embodiment, the pixel position is determined from the mechanical position of the transfer roller 1 detected by using the rotary encoder 11, so that the pixel position accuracy is good. Also, since the on / off ratio within the pulse width of the basic pulse can be changed,
It has an excellent effect that the print area change in the pixel can be controlled from 0 to 100%, and the number of gradation expressions is increased. In other words, an image with less distortion can be expressed by improving the image position accuracy, and since gradation expression is performed with the ON / OFF ratio within the pulse width of the basic pulse, ink scraping work that is faithful to gradation data is performed. Therefore, a clear image can be expressed, and the image quality can be improved by increasing the number of gradation expressions. Further, it has many excellent advantages as compared with the conventional dot matrix method, such as the mechanism and control thereof being simple.

In this embodiment, the F / V converter 12 and D / A
The basic pulse control voltage signal and the ON / OFF ratio control voltage signal are input to the pulse generator 13 via the converter 16.
Although the ON / OFF ratio within the pulse width of the basic pulse sent from is changed, the pulse of the basic pulse is changed according to the gradation data even in the circuit configuration using the counter and the flip-flop as shown in FIG. The on / off ratio within the width can be changed. That is, if the total number of gradations is set as a counter value in the counter 19 and a pulse generated in a cycle in which the pixel formation time is divided by the total number of gradations is input to the counter 19 as a count pulse, the transfer roller 1 From the input time point of the count start signal (pixel timing signal) that is input based on the mechanical position of (a in FIG. 5A).
Point), the countdown is started based on the count pulse, and when the total number of gray levels is counted to zero, the counter
19 sends out a zero pulse (b in FIG. 5 (a))
point). If a counter value (gradation data) corresponding to pixel data for each pixel is set in the counter 20 and the count start signal and count pulse are input in the same manner as the count 19, the countdown based on the count pulse is performed. When the counter is started and the set number of gradations is counted and becomes zero, the counter 20 sends out a zero pulse (Fig. 5 (b)).
Point c). That is, if the flip-flop 21 is set at the time of sending the zero pulse of the counter 20 and the flip-flop 21 is reset at the time of sending the zero pulse of the counter 19, the flip-flop shown in FIG. Based on the zero pulse sent by the counters 19 and 20, the basic time is from the input timing of the pixel timing signal to the sending timing of the zero pulse of the counter 19, and the flip-flop output of the flip-flop 21 within this basic time. The time width ratio (division ratio) of the “H” / “L” level of is changed.

〔The invention's effect〕

As described above, according to the head control method for the image printing apparatus of the present invention, the outer circumference of the head roller is determined based on the rotational position of the head roller including the blade for scraping the ink supplied and adhered to the outer peripheral surface thereof. By determining the pixel position to be formed on the surface and driving the blade based on the pixel data that is predetermined corresponding to this pixel position and scraping off the ink adhering to the head roller, the ink adhering area for each pixel is determined. Since the change is given, the ink adhesion area in the pixel formed on the outer peripheral surface of the head roller changes based on the pixel position, and the print area change in the pixel can be changed from 0 to 100%. In comparison with the conventional dot matrix system, the mechanism and control are simplified, and the number of gradations is increased to improve the image quality. Excellent effects that bets can.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing an actuator drive control circuit showing an embodiment of a head control method of an image printing apparatus according to the present invention, and FIG. 2 is an image printing to which the head control method of the image printing apparatus is applied. FIG. 3 is a side view showing an example of a head portion of the apparatus, FIG. 3 is a view showing a basic pulse in its pulse generator in the actuator drive control circuit shown in FIG. 1, and FIG. 4 is another embodiment of this actuator drive control circuit. FIG. 5 is a diagram showing an example, FIG. 5 is a time chart for explaining the operation of the actuator drive control circuit, and FIG. 6 is a diagram for explaining gradation expression by the conventional dot matrix system. 1 ... Transfer roller, 1a ... Outer surface, 4a ... Supply ink, 5 ... Blade, 6 ... Actuator, 11 ... Rotary encoder, 12 ... F / V converter, 13 ... Pulse generator, 14 …… control device, 15 …… RAM, 16…
… D / A converter.

Claims (1)

[Claims] 1. A pixel position to be formed on the outer peripheral surface of the head roller is determined based on the rotational position of a head roller provided with a blade for scraping off the ink supplied and adhered to the outer peripheral surface thereof. Head control of an image printing apparatus for driving the blade based on pixel data predetermined corresponding to the above, and scraping off the ink adhering to the head roller to change the ink adhering area for each pixel. Method.