JP2000190464A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the reading of a predetermined pattern after superposedly recording the data of the predetermined pattern on image data. SOLUTION: The discharging data of ink is produced by adding in an adder 26 data generated from a machine number pattern generating cirucit and image data quantized in a quantizing circuit 23. While, the discharging data of a liquid while insolubilizes and agglomerates the coloring material in the ink, is produced in a circuit 27. On the basis of these data, the liquid is give at least to the discharging locations of the ink on a recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, for example, to an image forming apparatus for forming a color image on a recording medium.

[0002]

2. Description of the Related Art Conventionally, various countermeasures have been incorporated in a color image forming apparatus in order to prevent forgery of a specific document such as bills and securities. As one of the methods, there is a method of superimposing a symbol unique to the image forming apparatus, which is difficult to visually recognize, on the image with a fixed modulation amount on an image in order to specify the used image forming apparatus.

If securities are forged using the image forming apparatus, if a reading device capable of extracting the forged product only in a specific wavelength range is used and a symbol unique to the image forming apparatus is read, Identify the image forming device used,
It is a good clue in tracking forgers.

However, when the above image information is superimposed by the ink jet recording method, if printing is performed on a recording medium such as plain paper which does not have water resistance and is feathered, a symbol unique to the image forming apparatus is read. In some cases, it has been difficult to track counterfeiters. But,
In recent years, water-resistant, high-quality printed images on plain paper have been required in the market, and a method of improving image quality without improving feathering on plain paper by improving ink has been considered. .

[0005] As a method of improving the water resistance of an image by improving the ink, for example, a method of imparting water resistance to a color material contained in the ink is known. Basically, since it is hardly redissolved in water after drying, there is a problem that the nozzles of the print head are easily clogged and difficult to recover. Although it is possible to prevent this, there is a problem that the configuration of the device becomes complicated.

Japanese Patent Application Laid-Open No. 56-84792 discloses a method in which a material for fixing a dye to a printing material is coated in advance. However, this method requires the use of a specific print medium,
In order to apply a material for fixing the dye, it is inevitable that the apparatus becomes larger and the cost increases. Furthermore, it is difficult to apply a material for stably fixing a dye on a printing material in a predetermined thickness.

Japanese Patent Application Laid-Open No. 64-63185 discloses a technique in which a colorless ink for insolubilizing a dye is deposited on a printing material by an ink jet print head. In this method, since the diameter of the colorless ink dot is larger than the dot diameter for image printing, desired characteristics can be satisfied even when the landing positions of the image ink and the colorless ink are shifted.

However, in this method, a colorless ink printability improving liquid (hereinafter referred to as P liquid) is applied over the entire area where an image is formed, so that the consumption of the P liquid is large and the running cost is increased. There are drawbacks to invite. In addition, since the ink is applied to the printing material more than usual, the ink drying position becomes longer, and the ink landing position shifts due to the ink adhesion and unevenness (cockling) of the printing material generated in the drying process. There is also a problem that occurs. In particular, when a color image is formed, a landing position shift due to the unevenness leads to color unevenness, and there is a problem that image quality is significantly impaired.

Therefore, it has been considered to print the P liquid on the basis of the image data for printing the color ink in order to improve the printability in the first term.

FIG. 2 shows an example of a superimposed pattern for reading symbols of the image forming apparatus. Print pixels indicated by 202 are pixels for determining when printing is performed on a white background. On the other hand, as shown in 201, pixels which are not printed even when image data comes, and when a color having a wavelength close to that of the superimposed pattern is struck, forcibly extracting white to increase the weaving rate of the entire pattern. Pixel.

At this time, it is preferable to use an ink having a wavelength that is difficult to visually recognize as a pattern printing ink. Also, the pattern is not limited to this, and it is preferable to use a pattern that is difficult to confirm visually.

Next, the flow of a signal for image processing in the conventional recording apparatus will be described with reference to the block diagram shown in FIG. In FIG. 3, the luminance signal of the image is obtained by the CCD 105,
This luminance signal is converted into a digital luminance signal by the A / D converter 106. In the obtained luminance signal, the sensitivity variation of each CCD element is corrected by the shading circuit 20, and the corrected luminance signal is converted into a density signal by the LOG conversion circuit 21.

Further, the LUT (Lo) is set so that the γ characteristic of the printer at the time of initial setting matches the original image density with the output image.
ok Up Table) 22 and the signal is quantized by a quantization circuit 23.

Separately, the machine number pattern generation circuit 24
The pattern sent from the printer is added to the quantized data by the adding circuit 26, and while being sent to the printer head 9, the P liquid image data generating circuit creates image data for printing the P liquid, Is sent to the head 9 to form an image as image data to which the superimposed pattern is added.

It is preferable to adopt a pattern that is inconspicuous among patterns corresponding to numbers and characters as the machine number pattern.

[0016]

When such a pattern is printed, if there is a pixel which is not printed in white as indicated by 201 in FIG. 2, the P liquid is not printed on that pixel. When a dot for printing a pixel has a landing position shift, the landed dot causes feathering, the area of white spots becomes small, and it may be difficult to determine a symbol unique to the printing apparatus.

FIG. 4A shows a case where the liquid P has landed beforehand without the color ink dots being shifted from the recording pixels. FIG. 4B shows a case where the position of the liquid P has shifted from the color ink. It shows the image when it has been lost.

Since the P liquid is not applied to the pixels where the color ink is not applied, when the recording landing point of the color ink is shifted to the left in the drawing, the color ink is applied for feathering as shown in FIG. When the image is recorded at a wavelength in the vicinity of the superimposed pattern, it may be difficult to determine the superimposed pattern.

The present invention has been made in view of the above-described problems of the conventional example, and has as its object to record a predetermined code in an appropriate size so as not to be affected by bleeding. An object of the present invention is to provide an image forming apparatus capable of performing the following.

[0020]

According to the present invention, there is provided a recording section for discharging ink onto a recording medium, and a recording medium for contacting the ink with a liquid for insolubilizing or collecting a color material in the ink. An image forming apparatus that forms an image on a recording medium using a liquid discharge unit that discharges a predetermined pattern of image data, and a superimposing unit that superimposes a predetermined pattern of image data on image data to be recorded, based on the predetermined pattern image data. Means for generating liquid application data for applying the liquid to at least the recording location of the predetermined pattern on the recording medium; and driving the recording section based on the image data generated by the superimposing means, thereby driving the recording section on the recording medium. Drive control to apply ink to the recording medium and apply the liquid onto a recording medium by driving the liquid ejection unit based on the liquid application data generated by the liquid application data generating means. Characterized in that it comprises a drive control means for performing.

The recording section and the liquid discharge section each have a heating element for each discharge port, and the ink or liquid is discharged from the discharge port by the pressure of bubbles generated by causing film boiling of the ink or liquid by heat. A bubble jet method or an ink jet method using a piezo element is applicable. Examples of the liquid that insolubilizes or aggregates the coloring material in the ink upon contact with the ink include, for example, Japanese Patent Application Laid-Open
It is possible to use the processing liquid described in JP-A-226057.

According to the horizontal structure, the generating means generates a predetermined pattern signal, the control means controls a predetermined pattern shape generated by the generating means in accordance with the input signal, controls the dots of the P liquid, The superimposing means superimposes a predetermined pattern signal obtained by the control means on the input signal.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the following embodiment, an example of a copying machine (full-color image forming apparatus) is shown as an application example of the present invention, but the present invention is not limited to this, and it is needless to say that the present invention can be applied to various other apparatuses. .

<First Embodiment> An embodiment of the present invention will be described below by taking an ink-jet type full-color image forming apparatus as an example. However, an image forming method such as an electrophotographic method, a mature transfer method, and a sublimation type method will be described. The present invention is also effective for a recording method in which an image is thinned out and output using the same image data.

FIG. 1 is a schematic diagram showing the state of recording and scanning of a color image in the first embodiment. Platen glass 1
The original 101 placed on the image 05 is imaged on the CCD 102 by the light source 103 and the optical lens 104, and is converted into an image signal corresponding to the amount of received light. The image signal is converted to a digital value by the A / D converter 106,
After the image processing, the recording heads 3C, 3M, 3
Send data to Y, 3K.

The recording medium 5 wound into a roll
Is held by the feeding roller 3 via the conveying rollers 1 and 2,
The sheet is fed in the direction f in the figure as the sub-scanning motor 50 connected to the feed roller 3 is driven. Guide rails 6 and 7 are placed in parallel across the recording material 5 and a carriage 8
The recording head unit 9 mounted on the scanner scans left and right.
The carriage 8 is equipped with heads 9Y, 9M, 9C, 9Bk of four colors of yellow, magenta, cyan, and black, and ink tanks of four colors are arranged on these heads.
The recording material 5 is intermittently fed by the print width of the recording head 9, but when the recording material 5 is stopped,
Direction, and the quantized image signal is
7 and ejects ink droplets in accordance with the signal to record an image.

Next, the operation of the above configuration will be described. FIG.
FIG. 3 is a block diagram illustrating a flow of a signal of image processing in the image forming apparatus of the present invention.

1 and 5, a luminance signal of an image is obtained by the CCD 102, and the luminance signal is converted into a digital luminance signal by the A / D converter 106. In the obtained luminance signal, the sensitivity variation of each CCD element is corrected by the shading circuit 20, and the corrected luminance signal is converted into a density signal by the LOG conversion circuit 21.

Further, the γ characteristic of the printer at the time of the initial setting is converted by the LUT 22 so that the original image density and the output image match, and the signal is quantized by the quantization circuit 23.

Apart from this, the machine number pattern generation circuit 24
Is sent to the quantized data by an adding circuit 26. Further, based on the data of the superimposed pattern and the signal of the image data, the image data for the P solution is created by the image data creating circuit 27 for the P solution and sent to the head 9.

In this case, the image data is created so that the P liquid is also applied to pixels in the superimposed pattern for which printing is not forcibly performed.

In FIG. 6, reference numeral 601 denotes a pixel to which a superposition pattern and P liquid are applied, and 602 denotes a pixel to which only P liquid is applied.

P is also applied to the portion 602 where no color ink is printed.
By applying the liquid, it is possible to suppress feathering, which occurs due to a shift in the landing position, etc., and a portion that appears white as compared with a case where the P liquid is not forcibly applied to a pixel that is not forcibly printed. And the recognition rate of a symbol unique to the image forming apparatus increases.

<Second Embodiment> In the first embodiment, the P liquid is printed over the entire area of the pixel where the color ink is not printed in the superimposed pattern. However, in the present embodiment, the P liquid is applied to the superimposed pattern. It is characterized in that printing is performed only on the printed pixel and its adjacent one pixel.

FIG. 7 is a diagram of a pattern for printing P liquid and color ink, which is implemented in the present embodiment.

Here, reference numeral 701 denotes a pixel to which a superposition pattern and P liquid are applied, 702 denotes a pixel to which only P liquid is printed,
03 indicates a pixel to which nothing is applied.

FIG. 8 is a block diagram showing the flow of an image processing signal in this embodiment.

An image luminance signal is obtained by the CCD 102,
This luminance signal is converted into a digital luminance signal by the A / D converter 106. In the obtained luminance signal, the sensitivity variation of each CCD element is corrected by the shading circuit 20, and the corrected luminance signal is converted into a density signal by the LOG conversion circuit 21.

Further, the γ characteristic of the printer at the time of the initial setting is converted by the LUT 22 so that the original image density matches the output image, and the signal is quantized by the quantization circuit 23.

Apart from this, the machine number pattern generation circuit 24
Is sent to the quantized data by an adding circuit 26. Further, based on the data of the superimposed pattern and the signal of the image data, the image data for the P liquid is printed by the image data generating circuit 27 for the P liquid by the image data and only one pixel adjacent to the pixel is printed. Data is created and sent to the head 9.

By printing the P liquid only on the pixels that affect the shape of the symbol unique to the image forming apparatus, not only the consumption of the P liquid is reduced, but also the symbol unique to the image forming apparatus without feathering. Can be printed.

<Third Embodiment> In this embodiment, the dot diameter of the P liquid ejected from the recording head is changed by changing the pulse waveform applied to the heater when the ink is ejected from the head, and the ink is superimposed. It is characterized in that feathering when printing a pattern is suppressed.

FIG. 9 shows a print pattern in this embodiment.

Reference numeral 201 denotes a pixel on which no printing is performed;
Denotes a pixel that prints with the same dot diameter for both the P liquid and the superimposed pattern, and 203 denotes a pixel that strikes the P liquid with a dot diameter larger than the superimposed pattern and the superposed pattern.

FIG. 10 is a block diagram showing the flow of signals for image processing according to this embodiment.

An image luminance signal is obtained by the CCD 102,
This luminance signal is converted into a digital luminance signal by the A / D converter 106. In the obtained luminance signal, the sensitivity variation of each CCD element is corrected by the shading circuit 20, and the corrected luminance signal is converted into a density signal by the LOG conversion circuit 21.

Further, the γ characteristic of the printer at the time of initial setting is converted by the LUT 22 so that the original image density matches the output image, and the signal is quantized by the quantization circuit 23.

Separately, the machine number pattern generation circuit 24
Is sent to the quantized data by an adding circuit 26. Further, print data of the P liquid is created by the P liquid image data generation circuit 27 from the data of the superimposed pattern and the image data, and sent to the head 9.

FIG. 11 shows an example of the setting of the pulse width for printing the 203 pixels shown in FIG.

When 51 is a pre-heat pulse and 52 intervals (no-pulse period) 53 are main heat pulses, the discharge amount is controlled by the pre-heat pulse and the interval, and discharge is performed by the main heat pulse.

Here, when printing is performed with a preheat pulse of 1.5 μS (1 μsec) for plain paper printing, a dot diameter of about 70 μm is formed on the recording medium. The dot diameter of the adjacent pixel can be increased by extending the preheat pulse to 2.0 μS.

When printing is performed with this pulse, a signal can be sent from the P liquid image data generation circuit 27 to the pulse width control circuit 28 at the timing of printing a pixel whose dot diameter is to be increased. The dot diameter is controlled by varying the preheat pulse.

In this embodiment, by suppressing printing of the P liquid as much as possible, not only the consumption of the P liquid can be reduced but also cockling (paper waving) can be suppressed as compared with the second embodiment. Even if the landing positions of the P liquid and the color ink are shifted, a high-quality image free from feathering can be obtained.

In the above embodiment, a code may be added using yellow or the like by utilizing the fact that human eyes have a low yellow discrimination ability so that the pattern is not visually recognized.

At the time of judgment, observation is made through a band filter of about 350 nm, and only the yellow signal is separated, so that it is easy to read.

[0056]

As described above, according to the present invention,
For example, if a serial number unique to a copying machine or a code obtained by encoding the serial number is represented by an additional pattern and used for illegal copying, etc., it can be used by identifying unauthorized copies. The specified copying machine can be specified. In addition, when recording by adding a pattern to the output image, the size of the pattern can be changed so that reading of the pattern is not difficult when the print engine controls the thinning of the image signal regardless of the image signal. This also has the advantage that the decoding of the additional information is more reliable.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. The present invention is also applicable to a case where the present invention is achieved by supplying a program to a system or an apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a state of recording and scanning of a color image according to a first embodiment.

FIG. 2 is a diagram showing a conventional recording pattern.

FIG. 3 is a block diagram of image processing.

FIG. 4 is a diagram showing an example of a conventional machine number pattern.

FIG. 5 is a block diagram according to the first embodiment.

FIG. 6 is a diagram illustrating an example of a machine number pattern according to the first embodiment.

FIG. 7 is a diagram illustrating an example of a machine number pattern according to the second embodiment.

FIG. 8 is a diagram illustrating a block diagram according to a second embodiment.

FIG. 9 is a diagram illustrating an example of a machine number pattern according to the third embodiment.

FIG. 10 is a diagram illustrating a block diagram according to a third embodiment.

FIG. 11 is a diagram for explaining pulse width setting in a third embodiment.

[Explanation of symbols]

 5 Recording Material 8 Carriage 9 Head 23 Quantization Circuit 24 Machine Number Pattern Generation Circuit 26 Addition Circuit 27 Image Data Creation Circuit for P Liquid 41 Nozzle 101 Document 102 CCD 106 A / D Converter

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA04 EA06 EA11 EC69 EC75 ED05 EE02 EE17 EE18 FA03 FA10 2C057 AF21 AF25 AG12 AG46 AH01 AM28 AN01 CA05 CA10

Claims (5)

[Claims] A recording unit for discharging ink onto a recording medium;
An image forming apparatus that forms an image on a recording medium using a liquid ejection unit that ejects a liquid that insolubilizes or aggregates a coloring material in the ink by contacting the ink with the recording medium. Superimposing means for superimposing image data of a predetermined pattern, based on the image data of the predetermined pattern, means for generating liquid application data for applying the liquid to at least a recording location of the predetermined pattern on the recording medium, The recording unit is driven based on the image data generated by the superimposing unit to apply ink on the recording medium, and the liquid ejection unit is driven based on the liquid application data generated by the liquid application data generating unit to record the recording medium. An image forming apparatus comprising: a driving control unit that performs driving control for applying the liquid. 2. The liquid application data generating unit generates liquid application data such that the liquid is applied to both a recording location of the predetermined pattern and a portion other than the recording location on a recording medium. The image forming apparatus according to claim 1. 3. The liquid application data generating unit creates liquid application data such that the liquid is also applied to pixels adjacent to a recording location of the predetermined pattern on a recording medium. The image forming apparatus as described in the above. 4. The apparatus according to claim 1, wherein the drive control unit controls the driving of the liquid application unit such that the dot diameter of the liquid is larger than the dot diameter of the ink on a recording medium. 2. The image forming apparatus according to 1. 5. The image forming apparatus according to claim 1, wherein the recording unit and the liquid ejection unit include a thermal energy generator that generates thermal energy used for ejection.