JPH0825318B2 - 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 the print density in the pixel.

[Conventional technology]

Conventionally, as a method of forming a gradation image in printer technology, an area ratio in a pixel is used in all, such as a dot matrix method, an ink jet method or an n × m matrix method, or a roller transfer method using a line width. The gradation expression method of operating was adopted.

[Problems to be solved by the invention]

However, according to such a method for forming a gradation image, the control contents are very complicated, for example, the pixels are further divided to give a signal in order to fill the matrix with ink, or the pixels are divided by the line width. It was In addition, the roller transfer method causes stains and the like due to uneven scraping of ink, and the quality is impaired.

[Means for Solving Problems] The present invention has been made in view of such problems,
The position of a pixel formed on the outer peripheral surface of the head roller is detected based on the rotational position of the head roller provided with a blade for scraping the ink supplied and adhered to the outer peripheral surface, and the pixel position is detected in advance corresponding to this pixel. By reading out the determined pixel data and varying the scraping thickness of the ink adhered by the blade according to the pixel data,
The ink adhesion density is changed for each pixel.

[Action]

Therefore, according to the present invention, the ink adhesion density in the pixel formed on the outer peripheral surface of the head roller changes depending on the scraped thickness of the supplied adhesion ink based on the pixel data corresponding to the pixel.

〔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 supplied (attached) to the outer peripheral surface 1a of the transfer roller 1 via the ink supply roller 3 and the auxiliary roller 2,
Ink 4a supplied and attached to the outer peripheral surface 1a of the transfer roller 1
However, the blade 5 is scraped off by driving the actuator 6. That is, the tip surface of the blade 5 is transferred to the transfer roller 1 according to the drive amount of the actuator 6.
It moves in the direction of contacting the outer peripheral surface 1a, and the supplied adhered ink 4a on the outer peripheral surface 1a is scraped off by its tip surface. In the figure, 7 is a paper surface to which the pixels formed on the outer peripheral surface 1a of the transfer roller 1 are to be transferred, 8 is a drain receiver of the ink scraped off by the blade 5, and 9 is an outer circumference thereof after the transfer to the paper surface 7. A cleaning blade for scraping off the ink remaining on the surface 1a and a drain receiver 10 for scraping off the ink of 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 control device which receives as input a pixel position detection pulse based on the mechanical position (rotational angle position) of the transfer roller 1,
12 is RAM, 13 is a D / A converter, and 14 is an amplifier. The pixel position detection pulse is generated based on detection of the mechanical position of the transfer roller 1 by a rotary encoder (not shown), and detection of the pixel position to be formed on the outer peripheral surface 1a of the transfer roller 1. The signal is input to the control device 11. In accordance with the input timing of the pixel position detection pulse, the control device 11 reads the gradation data (pixel data) stored in advance corresponding to the pixel at the detection position from the RAM 12, and also reads the read gradation data. It plays a role of giving the D / A converter 13 immediately. The D / A converter 13 does not send an output signal having a voltage value corresponding to the grayscale data based on the grayscale data input via the control device 11, and the output signal is input to the amplifier 14. It has become so. That is, the D / A converter 13 is
It has an output voltage value decomposed into 256 with respect to the 8-bit grayscale data stored in, and this output voltage value is input to the actuator 6 after being amplified by the amplifier 14 to a value sufficient for its driving. It is supposed to be done. Then, by driving the actuator 6 according to the output voltage value of the amplifier 14, the tip end surface of the blade 5 becomes the outer peripheral surface of the transfer roller 1.
It is configured to be driven in a direction in contact with 1a and to scrape the supplied adhered ink 4a on the outer peripheral surface 1a.

That is, in the actuator drive control circuit configured as described above, when the pixel position detection pulse is input to the control device 11, the grayscale data stored in advance corresponding to the pixel at the detection position is read from the RAM 12. The read gradation data is immediately input to the D / A converter 13. Then, a voltage value corresponding to the input gradation data (the number of gradations) is selected, amplified by the amplifier 14, and then the actuator 6 is driven based on the amplified voltage value. That is, the drive amount of the actuator 6 is determined according to the gradation data read corresponding to the pixel, and the tip end surface of the blade 5 is brought into contact with the outer peripheral surface 1a of the transfer roller 1 according to the drive amount of the actuator 6. The amount of movement of the blade 5 is determined, and by the amount of movement of the blade 5,
The scraping amount of the adhered ink 4a on the outer peripheral surface 1a of the transfer roller 1 changes. That is, the density of the adhered ink remaining after being scraped off on the outer peripheral surface 1a of the transfer roller 1 is changed by an analog operation of the blade 5 in accordance with the gradation data, and due to this density change, the paper surface 7 is changed. It is possible to express gradation for each pixel to be printed on.

As described above, according to the head control method of the image printing apparatus according to the present embodiment, since it is possible to change the density of the adhered ink according to the gradation data in the pixel, it is possible to express a more detailed gradation, The smoothness of the image is maintained and a deep image can be obtained. Also,
There is no stain due to uneven scraping of ink, and the quality of the image can be improved as compared with the conventional gradation expression method that operates the area ratio. Further, since there is no vibration due to the contact between the surface of the transfer roller 1 and the blade 5, the number of gradations does not decrease, and image printing equivalent to image data can be performed.

〔The invention's effect〕

As described above, according to the head control method of 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 on the outer peripheral surface thereof. Ink for each pixel is detected by detecting the pixel position formed on the surface and reading out pixel data predetermined corresponding to this pixel, and varying the scraping thickness of the ink deposited and supplied by the blade according to this pixel data. Since the adhesion density is changed, the ink adhesion density in the pixel formed on the outer peripheral surface of the head roller changes according to the scraping thickness of the supplied adhesion ink based on the pixel data corresponding to that pixel, It is possible to improve the quality of the image as compared with the gradation expression method of operating the area ratio of.

[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. It is a side view which shows an example of the bed part of an apparatus. 1 ... Transfer roller, 1a ... Outer surface, 4a ... Supply ink, 5 ... Blade, 6 ... Actuator, 11 ... Control device, 12 ... RAM, 13 ... D / A converter, 14
……Amplifier.

Claims (1)

[Claims] 1. A pixel position to be formed on the outer peripheral surface of the head roller is determined on the basis of the rotational position of a head roller provided with a blade for scraping off the ink supplied and adhered to the outer peripheral surface, and the pixel position is determined. An image printing apparatus configured to read pixel data that is predetermined correspondingly and change the scraped thickness of the ink deposited by the blade according to the pixel data to change the ink deposition density for each pixel. Head control method.