JP7389542B2 - image forming device - Google Patents

Description

The present invention relates to an image forming apparatus, an image processing apparatus, and a program.

2. Description of the Related Art Techniques for creating printed matter in which images such as characters, marks, and designs appear and disappear have been known for some time.

For example, Patent Document 1 describes an apparatus that achieves clearly visible printing using transparent fluorescent toner. Further, Patent Document 2 describes an image forming apparatus that creates an unreproducible image pattern using an invisible toner (I toner) containing an infrared absorber and a transparent toner (T toner) not containing a pigment. Further, Patent Document 3 describes an image forming apparatus that forms hidden information on a recording medium that can be identified only under special conditions using fluorescent toner and transparent toner. Furthermore, in Patent Document 4, when forming counterfeit prevention information on images recorded on recording media, two types of recording materials are used: a colorless and transparent recording material, a white recording material, and two types of similar colors with different gloss levels. An image recording apparatus is described that uses a recording material, a black color using a black recording material, and a process black color formed using recording materials of three colors: yellow, magenta, and cyan.

Japanese Patent Application Publication No. 2004-102008 Japanese Patent Application Publication No. 2010-171497 Patent No. 5866977 Japanese Patent Application Publication No. 2003-326802

An object of the present invention is to realize a visual effect in which images appear and disappear using metallic toner.

In the invention according to claim 1, a first image consisting of a first partial image and a second partial image adjacent to the first partial image is formed on a medium using a metallic toner, and a second partial image is formed using a color toner. a forming means for forming two images on the medium; and a forming means for forming two images on the medium so that in an area on the medium where the first image and the second image overlap, the metallic toner is a lower layer and the color toner is an upper layer. and a control means for controlling, wherein a user can set a level at which the image represented by the first image does not want to be noticeable, and according to the level at which the user does not want to make the image stand out, The image forming apparatus is characterized in that the difference in density of the metallic toner between the first partial image and the second partial image constituting the first image is adjusted.

According to the invention according to claim 1 or 2 , a visual effect in which an image appears and disappears is realized using metallic toner.

1 is a diagram showing a specific example of an image forming apparatus suitable for implementing the present invention. FIG. 2 is a diagram showing specific examples 1 to 3 of printing by the image forming apparatus of FIG. 1. FIG. FIG. 3 is a diagram showing specific examples 4 to 6 of printing by the image forming apparatus of FIG. 1;

FIG. 1 is a diagram showing a specific example of an image forming apparatus 100 suitable for implementing the present invention. The image input unit 10 receives, for example, image or document data provided from an external device such as a computer, or image or document data read by a scanner or the like. The image input section 10 outputs a plurality of color signals obtained from input image or document data to the color conversion section 20. For example, four color signals (C, M, Y, K) corresponding to the four colors C (cyan), M (magenta), Y (yellow), and K (black) regarding each pixel of an image or document are The image is output from the image input section 10.

The color conversion unit 20 determines the toner amount of each color toner corresponding to each color signal based on the plurality of color signals obtained from the image input unit 10. The color conversion unit 20 converts the four color signals (C, M, Y, K) obtained from the image input unit 10 into device-dependent four color signals (C′) according to the color reproduction characteristics of the print engine 50. , M', Y', K'). The four color signals (C', M', Y', K') after conversion by the color conversion section 20 correspond to the toner amounts of the four color toners of C, M, Y, and K, respectively. There is. For example, if each color signal before conversion is an area ratio, each color signal after conversion, that is, the amount of toner, is also expressed as an area ratio.

The color conversion unit 20, for example, determines the correspondence between the four color signals (C, M, Y, K) before conversion and the four color signals (C', M', Y', K') after conversion. Color conversion is performed using a four-dimensional LUT (lookup table) that defines relationships. Note that color conversion using a four-dimensional LUT is only one preferred example, and color conversion in the color conversion unit 20 is not limited to this example. For example, a color signal of three colors (R, G, B) may be used as a color signal before conversion, and a color signal of five or more colors (C, M) may be used as a color signal after conversion. , Y, K, O, V), etc. may be used.

The image forming apparatus 100 in FIG. 1 has a printing function using only four color toners of C, M, Y, and K, as well as a printing function using metallic toner and clear toner. The image forming apparatus 100 in FIG. 1 achieves a visual effect in which an image appears or disappears depending on the viewing angle by printing using metallic toner and clear toner.

For example, when the signal obtained from the image input section 10 includes image information regarding the first image (including characters, marks, etc.), the metallic toner adjustment section 30 adjusts the printing of the first image. Determine the amount of metallic toner to be used. The metallic toner adjustment section 30 adjusts the amount of metallic toner (Mt) obtained from the image input section 10, for example, and outputs the adjusted amount of metallic toner (Mt') to the print engine 50.

Note that preferred specific examples of metallic toner include silver toner and gold toner. Of course, metallic toners of metals other than gold and silver may also be used. Further, the metallic toner may be defined as having an FI (flop index) value of 1 or more, for example.

Furthermore, for example, when the density of an image formed using color toner is high, the first image may be formed using clear toner. In this case, the clear toner adjustment section 40 determines the amount of clear toner used for printing the first image. The clear toner adjustment section 40 adjusts the amount of clear toner (Cl) obtained from the image input section 10, for example, and outputs the adjusted amount of clear toner (Cl') to the print engine 50.

Note that preferred specific examples of clear toner include transparent toner. The transparent toner may be colorless and transparent or colored and transparent. Further, the clear toner may be defined as having an FI (flop index) value of less than 1, for example.

The print engine 50 is, for example, an electrophotographic full-color print engine using an intermediate transfer system, and uses four color toners of C, M, Y, and K as coloring materials, and the image may appear or disappear depending on the viewing angle. Metallic toner and clear toner are used to achieve the desired visual effect. The print engine 50 has, for example, a tandem type photoreceptor arrangement, and includes four photoreceptors corresponding to each of the four color toners of C, M, Y, and K, and one corresponding to metallic toner and clear toner. It has two photoreceptors.

Print engine 50 is controlled by an image processing block. For example, the toner amount of each color toner (C', M', Y', K') outputted from the color conversion section 20 and the toner amount of adjusted metallic toner outputted from the metallic toner adjustment section 30 (Mt' ) and the toner amount (Cl') of the adjusted clear toner output from the clear toner adjustment section 40, a toner image is formed on each photoreceptor, and the toner images of the plurality of photoreceptors are intermediately transferred one after another. It is transferred onto the body belt (primary transfer). As a result, a full-color toner image including a metallic toner layer, a clear toner layer, and four color toner layers of C, M, Y, and K is formed on the belt of the intermediate transfer member. This full-color toner image is transferred (secondary transfer) to a print medium such as paper, and further, the full-color toner image is fixed to the print medium.

The control unit 60 controls the entire interior of the image forming apparatus 100 shown in FIG. The overall control by the control unit 60 also reflects instructions received from the user via an operating device or the like.

At least a portion of the image forming apparatus 100 shown in FIG. 1 can be realized using a computer, for example. The computer includes arithmetic devices such as CPUs, storage devices such as memory and hard disks, communication devices that use communication lines such as the Internet, devices that read and write data from storage media such as optical disks and semiconductor memories, and display devices such as displays. It is equipped with hardware resources such as devices and operation devices that accept operations from users.

For example, a program (software) corresponding to the functions of at least some of the reference numerals in the image processing block included in the image forming apparatus 100 of FIG. At least some of the functions within the image processing block are realized by the computer through cooperation between the hardware resources and the loaded software. The program may be provided to the computer via a communication network such as the Internet, or may be stored in a storage medium such as an optical disk and provided to the computer.

The overall configuration of the image forming apparatus 100 in FIG. 1 is as described above. Next, processing etc. executed by the image forming apparatus 100 in FIG. 1 will be described in detail. Note that for the configuration (portion) shown in FIG. 1, the reference numerals in FIG. 1 will be used in the following description.

2 and 3 are diagrams showing specific examples of printing by the image forming apparatus 100 of FIG. 1. 2 and 3 show a specific example in which a background image made of color toner and a letter A made of metallic toner are formed in an overlapping manner.

In the area where the background image and the character A overlap, that is, in the area where the color toner and the metallic toner overlap, printing is performed so that the metallic toner is the lower layer and the color toner is the upper layer on the paper. The print engine 50, for example, forms metallic toner on paper and then performs additional printing to form color toner on top of the metallic toner. For example, the image processing block (FIG. 1) controls the print engine 50 to perform overprinting to form color toner on metallic toner. Since the metallic toner is in the lower layer than the color toner, the adverse effect on the image (background image) formed by the color toner is smaller than when the metallic toner is in the upper layer.

In Examples 1 to 3 shown in FIG. 2, metallic toner is printed around the letter A so as to hollow out the shape of the letter A, thereby forming the letter A on the paper. Furthermore, an image using color toner is formed on the background of the letter A.

Specific example 1 shows a state in which the density of the metallic toner is relatively small (low), and the intensity of the specularly reflected light MR from the metallic toner and the intensity of the specularly reflected light PR from the paper are almost equal. Note that the specularly reflected light is reflected light that is reflected at the same reflection angle as the incident angle of the incident light.

Therefore, in Example 1, when viewed from the angle of specularly reflected light, the letter A formed with metallic toner becomes difficult to see due to reflection from the paper and is hidden. On the other hand, when viewed at an angle of diffusely reflected light that is different from the angle of specularly reflected light, the letter A becomes easier to see because the diffusely reflected light from the metallic toner is relatively strong. In other words, a visual effect is achieved in which the letter A appears or disappears depending on the viewing angle.

Specific example 2 shows a state in which the density of the metallic toner is relatively large (high), and the intensity of the specularly reflected light MR from the metallic toner is stronger than the intensity of the specularly reflected light PR from the paper. Therefore, in Example 2, even when viewed from the angle of specularly reflected light, the letter A formed with metallic toner is not hidden by reflection from the paper. Note that when viewed from an angle of diffusely reflected light that is different from an angle of specularly reflected light, the letter A becomes more visible than from an angle of specularly reflected light because the diffusely reflected light from the metallic toner is relatively strong. In other words, a visual effect is achieved in which the appearance of the letter A changes depending on the viewing angle.

As shown in Example 2, by increasing the density of the metallic toner, the letter A becomes more visible. Therefore, for example, if the density of an image (background image) formed using color toner becomes high and the letter A becomes difficult to see, the density of the metallic toner is increased (increased) to make the letter A more visible. It is desirable to adjust as follows. Note that, for example, a configuration may be adopted in which the user can set a level (degree) at which he or she does not want to be noticeable, and the density of the metallic toner may be adjusted according to the set level.

Specific example 3 is a specific example that utilizes the density difference of metallic toner. In specific example 3, high-density metallic toner is printed around the letter A, and low-density metallic toner is printed on the shape of the letter A. In specific example 3, the visibility of the letter A changes due to the difference in intensity between the specularly reflected light MR from the high-density metallic toner and the specularly reflected light MR' from the low-density metallic toner, that is, the difference in density of the metallic toner. .

Therefore, for example, if the density of an image (background image) formed using color toner becomes high and the letter A becomes difficult to see, it is possible to increase the density difference between metallic toners to make the letter A more visible. Adjustment is desirable. Note that if it is not desired to make a hidden image such as the letter A stand out, it is desirable that the density difference ΔCin% of the metallic toner be less than 20%, for example.

In specific examples 4 and 5 shown in FIG. 3, metallic toner is printed on the shape of the letter A to form the letter A on the paper. Further, in Specific Example 6, clear toner is used instead of metallic toner. In Examples 4 to 6, an image using color toner is formed on the background of the letter A.

Specific example 4 shows a state in which the density of the metallic toner is relatively small (low), and the intensity of the specularly reflected light MR from the metallic toner and the intensity of the specularly reflected light PR from the paper are almost equal. Note that the specularly reflected light is reflected light that is reflected at the same reflection angle as the incident angle of the incident light.

Therefore, in specific example 4, when viewed from the angle of specularly reflected light, the letter A formed with metallic toner becomes difficult to see due to reflection from the paper and is hidden. On the other hand, when viewed at an angle of diffusely reflected light that is different from the angle of specularly reflected light, the letter A becomes easier to see because the diffusely reflected light from the metallic toner is relatively strong. In other words, a visual effect is achieved in which the letter A appears or disappears depending on the viewing angle.

Specific example 5 shows a state in which the density of the metallic toner is relatively large (high), and the intensity of the specularly reflected light MR from the metallic toner is stronger than the intensity of the specularly reflected light PR from the paper. Therefore, in Example 5, even when viewed from the angle of specularly reflected light, the letter A formed with metallic toner is not hidden by reflection from the paper. Note that when viewed from an angle of diffusely reflected light that is different from an angle of specularly reflected light, the letter A becomes more visible than from an angle of specularly reflected light because the diffusely reflected light from the metallic toner is relatively strong. In other words, a visual effect is achieved in which the appearance of the letter A changes depending on the viewing angle.

As shown in Example 5, by increasing the density of the metallic toner, the letter A becomes more visible. Therefore, for example, if the density of an image (background image) formed using color toner becomes high and the letter A becomes difficult to see, the density of the metallic toner is increased (increased) to make the letter A more visible. It is desirable to adjust as follows. Note that, for example, a configuration may be adopted in which the user can set a level (degree) at which he or she does not want to be noticeable, and the density of the metallic toner may be adjusted according to the set level.

Specific example 6 is a specific example in which clear toner is used instead of metallic toner. For example, when compared at the same toner density, the intensity of specularly reflected light CR from clear toner is greater than the intensity of specularly reflected light MR from metallic toner. Therefore, for example, if the density of an image (background image) formed using color toner becomes high and the letter A becomes difficult to see, using clear toner instead of metallic toner will make the letter A more visible. It is desirable to adjust as follows.

For example, the image forming apparatus 100 forms a hidden image such as the letter A using clear toner when the density of the background image formed using color toner is a high-density image equal to or higher than a threshold value. In the case of a low-density image below a threshold value, a hidden image such as the letter A is formed using metallic toner. Note that the threshold value (density Cin%) for identifying high-density images and low-density images is, for example, approximately 80% in the case of a monochrome image, and 4 colors (C, M, Y) in the case of a multicolor image. , K) is preferably about 100%.

The preferred embodiments of the present invention have been described above, and according to the described embodiments, a visual effect in which images appear and disappear using metallic toner is realized. Further, according to the above-described embodiment, for example, hidden characters such as a name or a message that are not to be noticed may be printed, or hidden characters (marks, etc.) may be printed for simple security purposes (for example, guarantee of originality). It may be printed, or a design value such as a hidden image may be added to the printed matter.

Note that the embodiments described above are merely illustrative in all respects, and do not limit the scope of the present invention. The present invention includes various modifications without departing from its essence.

Reference Signs List 10 image input section, 20 color conversion section, 30 metallic toner adjustment section, 40 clear toner adjustment section, 50 print engine, 60 control section, 100 image forming apparatus.

Claims (2)

A first image consisting of a first partial image and a second partial image adjacent to the first partial image is formed on a medium using metallic toner, and a second image is formed on the medium using color toner. forming means;
a control means for controlling the forming means so that in a region on the medium where the first image and the second image overlap, the metallic toner is a lower layer and the color toner is an upper layer;
has
A user can set a level at which the image represented by the first image does not want to be noticeable, and the first partial image forming the first image is set according to the level at which the user does not want to make it stand out. adjusting the density difference of the metallic toner between and the second partial image ;
An image forming apparatus characterized by: The image forming apparatus according to claim 1,
the first partial image is a hidden image;
the second partial image is an image formed around the hidden image;
adjusting the density difference between the density of the metallic toner in the first partial image and the density of the metallic toner in the second partial image according to the level set by the user to make it less noticeable;
An image forming apparatus characterized by:

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