JP2007144670A - Image forming system and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming system and an image forming method. <P>SOLUTION: The image forming method comprises a process which is used for forming an image on the surface of a three-dimensional body 24 and feeds thermoplastic particles on the surface of the body 24, a process which performs an image-like exposure with a laser light from a light irradiating system, irradiates the particles carried on the surface of the body 24 to melt them, and welds the particles in the image-like shape on the surface of the body 24, and a developing process which removes the particles which are not fused on the surface from the surface of the body 24, to be able to form an image with a high contrast to the surface of a variety of shapes. In addition, the image forming system performing the above described processes is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to image formation, and more particularly, to an image forming system and an image forming method for forming a colored image fused on an object surface.

  Up to now, various methods have been known for forming an image by delicately coloring a desired color to a desired location regardless of the uneven shape of the colored location, regardless of the material such as metal, glass, resin, paper, and wood. It has been. Examples of the image to be formed include a product logo, manufacturing date and lot number, names and descriptions of buttons of electric appliances and mobile phones, designs, character products, and the like.

  Conventionally, laser direct marking, screen printing, transfer printing, and ink jet printing are used as image forming methods for image formation such as printing on merchandise. For sheet-like members, impact dot printers, electrophotographic printers, ink jet printers, and thermal printers are in practical use. In addition, as a coloring / image forming method proposed by the present inventors, there is a laser plastic coloring method (hereinafter referred to as an LPC method).

  Hereinafter, a conventional image forming method will be described. In general, it can be summarized as follows.

<Laser direct marking>
Laser direct marking is a method of generating a visual difference by irradiating the surface of an image formation target with laser light and melting, foaming or modifying the surface. The image forming target is not particularly limited as long as it is a material that absorbs laser light. The shape of the image forming target is arbitrary, and there is an advantage that the image forming target can be processed in a non-contact manner.

<Screen printing>
Screen printing is a type of stencil printing that uses a screen of chemical fibers such as silk, tetron, and nylon for the plate, and makes holes in the plate itself and rubs ink through the holes. Screen printing has so far been able to print on any material such as paper, cloth, plastic, metal, glass, wood, printed circuit boards, and is known to be able to print not only flat objects but also solid objects and curved surfaces to some extent. It has been.

<Transfer printing>
Transfer printing is a method in which a transferable image once printed on paper, film, or the like is transferred to a target member using water, heat, pressure, or the like. Transfer printing has the advantage that printing can be performed if it has an uneven shape that allows the film to be in close contact, and printing accuracy is high and printing errors are few.

<Impact printing>
This printing method is systematized as an impact dot printer, and the impact dot printer strikes the shape of characters and images expressed by a plurality of points with a metal wire. The struck ink ribbon is fixed to the object in an image shape, and an image can be formed. Currently, many impact dot printers are used as business printers for making carbon copies.

<Inkjet printing>
Ink jet printing is a method of forming an image on an image forming target by ejecting ink particles onto a target member. Inkjet printing has the advantage of being able to handle a wide range of materials and shapes for coloring objects, such as cans, plastics, bottles, glass plates, coated boxes, pipes, electronic parts, and automobile parts, depending on the type of ink and jetting method. have.

  This printing method is systematized as an ink jet printer, and forms characters and images by ejecting ink droplets onto paper. Ink-jet printing is a continuous method in which ink droplets are ejected continuously and only the necessary ink droplets are guided to a predetermined position on the paper depending on the ink droplet ejection form and ejection energy generation method. There is an on-demand system that is ejected. Among the on-demand methods, the electromechanical conversion method and the electrothermal conversion method are widely adopted.

<Electrophotographic printing>
Electrophotographic printing has been systematized as an electrophotographic copying machine or an electrophotographic printer, utilizing the properties of photoconductivity and static electricity, and particles referred to as toner are used as the colorant. In general, the electrophotographic printer uses a charger to charge the photosensitive drum with static electricity. When the photosensitive drum is irradiated with a laser beam in accordance with the characters and images to be printed, the static electricity at that portion disappears. An image is formed. At this point, when the charged toner comes into contact with the photosensitive drum, the toner adheres only to the charged portion and forms an image corresponding to image-like exposure. Thereafter, the toner adhered on the photosensitive drum is transferred to plain paper or an OHP sheet, and the toner is fused by heat and pressure to fix the toner on the plain paper or OHP sheet. A laser beam method, an LED method, a liquid crystal shutter method, and the like have been proposed in accordance with a method for irradiating the surface of the photosensitive drum with light.

<Thermal transfer printing>
Thermal transfer printing is a method of printing characters and images using heat. Printers that use the thermal transfer system include thermal printers that use thermal paper that turns black when overheated, a transfer system that melts ink on the ink ribbon and transfers it to the paper, and sublimates or vaporizes dyes by heating to receive the image. Thermal sublimation transfer methods that transfer to materials are known, and as thermal transfer printers, thermal melting printers that melt pigment-based inks with ink ribbon materials and thermal sublimation printers that melt and sublimate dye-based inks are proposed. Has been.

<LPC method>
The LPC method proposed by the present inventors is a system in which a dye is diffused in a resin object such as acrylic to color an image. In the LPC method, a dye for resin is brought into close contact with the surface of an object to be colored, such as a resin plate or a resin film, and a laser beam is irradiated in an image shape to heat the portion irradiated with the laser beam, and the dye is applied only to the irradiated portion. The object to be colored is colored by moving and permeating the material. There are a sheet method and a jetting method as dye attachment methods by the LPC method. The former is often used for coloring a flat surface and the latter for coloring a three-dimensional object.

The details of the image forming method described above are described in detail in the following non-patent documents. Japanese Patent Application Publication No. 2004-525992 (Patent Document 1) discloses a method of forming an image by providing a laser-sensitive layer containing a colorant on a plastic surface and changing the hue by imagewise irradiation of a laser beam. Has been. Although the method disclosed in JP-T-2004-525992 can draw an image directly on the surface of an object, a colorant that fades by light irradiation is used in the first place. Is low in robustness, and does not matter the image forming property with respect to an object having a three-dimensional shape.
Edited by Takeda et al., Published by Academic Publishing Center, "Memory / Recording / Photosensitive Materials", October 20, 1985 Mitsuo Tsuji, published by the Printing Society of Japan, "Printing Image Engineering for Printing and Electrical Engineers", June 15, 1988 Edited by Electrophotographic Society, published by Corona Co., Ltd., “Basics and Applications of Electrophotographic Technology”, June 15, 1988 JP-T-2004-525992

  As described above, although various image forming methods have been proposed, there are the following problems when the image forming method known so far is applied particularly to a printing object having a three-dimensional shape. . Laser direct marking uses a visual difference directly formed on an object to be imaged, so that there is a problem that free color expression is difficult. Further, in screen printing, it is necessary to manufacture a mold for printing, and it is necessary to make the screen follow the surface to be colored.

  In transfer printing, since it is necessary for the film to be in close contact with the surface to be colored, it is difficult to print a sharp uneven shape, and there is an inconvenience that the image formability for various three-dimensional objects is poor. Inkjet printing also has the disadvantage that printing defects are likely to occur due to the problem of ink ejection stability. In addition, inkjet printing has a particular problem that it is difficult to perform high-speed printing on a sharp uneven shape because the flying time of ink particles depends on the distance between the nozzle and the target surface.

  In addition, although the convenience of image formation is improved in various printer systems, the configuration of all printers is based on the sheet shape, so it is difficult to print on uneven shapes, and image formation There is an inconvenience that the target material is largely limited. On the other hand, in the LPC method, the coloring target member is limited to the resin material, the coloring density is low, and in order to obtain a sufficient coloring density, it is necessary to irradiate the same pixel portion with a laser multiple times, On the other hand, in addition to the difficulty of stable coloring, there is a problem that it is difficult to obtain a high resolution because the coloring contrast is low.

  As described above, it is possible to form an image having sufficient durability and contrast for an image forming target having a variety of shapes such as a three-dimensional solid, although various image forming techniques have been proposed so far. What is needed is an image forming system and method that is capable of doing this.

  In other words, an object of the present invention is to allow a desired color to be selectively applied to a desired position with respect to objects of various materials and complex shapes, so that a so-called stereoscopic color printer can be realized. It is to provide a method and a coloring system.

  As a result of diligent investigation, the present inventor has carried the particles on the surface of the object, melts the supported particles directly by a laser, and fuses the particles to the surface of the object. The present invention has been found out that it can be satisfactorily formed with respect to an object having sapphire.

That is, according to the present invention,
An image forming system for forming an image on the surface of an object,
A particle supply member for supplying thermoplastic particles to the surface of the object;
A light irradiation system for irradiating and melting the particles carried on the surface of the object, and fusing the particles in an image form on the surface of the object;
An image forming system comprising: a particle removing member that removes particles that are not fused to the surface from the surface of the object.

  In the present invention, the object may be a three-dimensional object, and the surface of the object may have a non-planar shape. The light irradiation system preferably includes a laser device and an optical system that modulates laser light from the laser device into an image. The optical system may comprise a light reflecting element or an optical mask. Furthermore, an electrostatic charge generating member or a magnetic field forming member for promoting the loading of the particles on the surface of the object may be included.

According to the present invention, there is also provided an image forming method for forming an image on the surface of an object using an image forming system,
Supplying an object to the imaging system;
Supplying thermoplastic particles from the particle supply member to the surface of the object;
Performing imagewise exposure from a light irradiation system, irradiating and melting the particles carried on the surface of the object, and fusing the particles imagewise to the surface of the object;
And a step of removing particles not fused to the surface from the surface of the object by a particle removing member.

The step of supplying the object of the present invention may include the step of providing a three-dimensional object in which the surface of the object is non-planar. The step of fusing may include a step of modulating laser light from the laser device into an image using an optical system. The step of fusing may include a step of supplying light energy of 0.5 J / cm ² or more to the particles to melt the particles. In the present invention, a step of promoting the loading of the particles on the surface of the object by an electrostatic charge generating member or a magnetic field forming member may be included before the supplying step. The present invention can include a step of changing the light energy to change the line width and density of the image. Further, the supplying step includes a step of rubbing the surface of the object by the particle supply member, a step of spraying the particles on the surface of the object, or a step of supplying the particles by electromagnetic interaction. it can. In the present invention, the removing step includes a step of rubbing the surface of the object by the particle supply member, a step of spraying a fluid on the surface of the object, or a step of removing the particles by electromagnetic interaction. be able to.

The image forming method of the present invention further includes a step of attaching particles of different hues on the object to the formed image, and
In the present invention, the particles having different hues may further include a step of melting the adhered particles having different hues with the laser light and mixing the hues with the hues of the already formed image. The step of including and fusing the colored particles may include a step of mixing the colored particles of different hues on the surface of the object by the laser irradiation.

  According to the present invention, an image forming system and an image forming method capable of forming a good image with high contrast and high fastness with respect to a three-dimensional object having various shapes and formed of various materials. Can be provided.

  The present invention will be described below with reference to embodiments shown in the drawings, but the present invention is not limited to the embodiments described below.

  FIG. 1 is a schematic diagram of an image forming system of the present invention. An image forming system 10 shown in FIG. 1 generally includes a laser device 12 and a control computer 14. The control computer 14 can be any computer known so far, and includes, for example, a central processing unit (CPU) such as PENTIUM (registered trademark) series, Windows (registered trademark), MACOS, Unix (registered trademark). A computer capable of operating an operating system such as Linux (registered trademark) can be used.

  The control computer 14 includes a memory such as a hard disk and an EEPROM (not shown), and the image data to be formed is converted into an appropriate format such as bitmap, JPEG, JPEG2000, TIFF, Windows (registered trademark) metafile, and GIF. Storing. After image processing by the user and creation of an image to be formed, the control computer 14 transmits a control signal in response to the image to be formed to the scanner controller 16 in response to a user command. The scanner controller 16 controls the oscillation of the scanner optical system 18 and the laser device 12 based on data from the control computer 14 and performs imagewise exposure toward the object 24 on which image formation is performed.

  The laser device 12 that can be used in the present invention supplies energy capable of melting particles such as toner to the particles within a predetermined time, and attaches the particles to an object on which image formation is performed. The laser device used in the present invention is not particularly limited, and a gas laser, a semiconductor laser, particularly a high-power semiconductor laser that can supply a light energy density necessary for the present invention, a solid-state laser, and the like can be used. . Among these lasers, in terms of energy density, a carbon dioxide laser, an excimer laser, or the like is preferably used as the gas laser, and Nd-YAG laser, ruby laser, sapphire laser, alexandrite laser is used as the solid-state laser. Etc. are preferably used.

  In the illustrated embodiment, the scanner optical system 18 further includes a condensing lens 20 for condensing the laser beam and a reflecting mirror 22 that is a light reflecting element. The condensing lens 20 condenses the laser light so as to give a desired dot size corresponding to the image to be formed. The reflection mirror 22 deflects the laser beam using a galvanometer, and irradiates the laser beam at a predetermined position of the image. The reflection mirror 22 and the condensing lens 20 are each mounted on an actuator mechanism including a motor controlled by the scanner controller 16, and the position and angle are controlled in response to a command from the scanner controller 16. . In the present invention, instead of the scanner optical system 18, an optical system that performs imagewise exposure on an object using an optical mask that forms a desired pattern from coherent light by Fourier transform can be used.

  The laser device 12 outputs a laser beam corresponding to a command from the scanner controller 16 by an optical shutter or a pulse modulator, thereby enabling imagewise exposure. In FIG. 1, the laser beam reflected by the reflecting mirror 22 is irradiated toward the object 24 to form an image. Particles such as toner are deposited on the object 24 by chemical or electrostatic or physical interaction such as magnetic force. The particles on the object 24 are melted in an image shape by the laser beam and fused to the surface of the object 24. In the present invention, the fusion occurs like an image. For this reason, when particles that have not been melted are removed from the surface of the object 24, a fused image 26 as shown in FIG. 1 is obtained.

  The particles that can be used in the present invention are not particularly limited. However, the toner used in the electrophotographic method can be used as the particles used in the present invention from the viewpoint of mass productivity and cost. The toner described above is usually a thermoplastic resin composition, and includes a thermoplastic resin, a colorant, a charge control agent, and a flow control agent in which inorganic or organic fine particles such as silica and alumina are used. It is formed including. The melting start temperature of the particles can be in a range of about 70 ° C. to 150 ° C. In consideration of melting and mixing a plurality of hues and CMYK in the present invention, it is preferable to use a toner for forming a full color image. . As such a toner, any known material, production method and material composition can be used. The particle size of the particles is preferably in the range of 2 μm to 20 μm in terms of volume average particle diameter, and can be in the range of 2 μm to 6 μm from the viewpoint of improving color mixing and forming a finer image. .

  Moreover, the thermoplastic resin contained in the particle | grains used for this invention can use the acrylic polymer or acrylic copolymer formed by superposing | polymerizing an acrylic monomer. Examples of acrylic monomers that can be used in the present invention include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methoxystyrene, p-ethylstyrene, and p-tertiarybutylstyrene. Acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate Acrylic esters such as phenyl acrylate; methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, methacrylate Methacrylic acid esters such as 2-ethylhexyl phosphate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylonitrile, methacrylonitrile In addition to acrylamide, etc., vinyl derivatives, specifically alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl ether, isobutyl ether; β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl ether, p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether, p-methoxyphenyl vinyl ether And diene compounds such as ether, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone, 2-vinylimidazole, N-methyl-2-vinylimidazole, N-vinylimidazole and butadiene. it can.

  In addition, in order to adjust the loading property of the particles on the surface of the object, the particles themselves may contain acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monobutyl itaconate, monobutyl maleate, phosphoric acid-containing simple substance. Mer, specifically, acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, sulfonic acid group-containing monomer, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, acroylmorpholine, 2-vinylpyridine, 3-vinylpyridine 4-vinyl pyridine, N-vinyl pyrrolidone, 2-vinyl imidazole, N-methyl-2-vinyl imidazole, N-vinyl imidazole and the like can be added to give preferable adhesion. In addition, these charge control agents can be attached to the surface of an object by a method such as spraying, and can be used to control the carrying properties separately from the particles.

  The particles used in the present invention can be colored using any coloring component known so far. Examples of the coloring component include organic colorants other than carbon black, specifically C.I. I. Direct Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as Basic Green 6; Cadmium Yellow, Mineral First Yellow, Navel Yellow, Naphthol Yellow S, Hansa Yellow G, Permanent Yellow NCG, Tartrazine Lake, Molybdenum Orange GTR, Benzidine Orange G, Cadmium Red 4R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Quinacridone, Rhodamine Lake, Phthalocyanine Blue, Fast Sky Blue, Pigment Green B, Macalite Green Lake, Final Yellow Green G, etc. However, it is not limited to these. In addition, these coloring components can be used by appropriately mixing them, and a coloring agent is not particularly required depending on the use of an image to be formed.

  In addition, when the adhesion of particles is controlled by an electrostatic charge, a charge control agent can be added to control the chargeability. As the charge control agent, any of a conventionally known positive charge control agent or negative charge control agent can be used.

  The volume average particle diameter of the particles used in the present invention can be measured using a sedimentation method, inertia method, diffusion method, mobility analyzer, light scattering method, pore electrical resistance method, and the like. For example, the measurement can be performed using any known device such as, for example, MULTISIZER ™ manufactured by Coulter.

  The object 24 that forms an image in the present invention may have various shapes and materials. For example, the material of the object 24 may be a plastic film, a ferromagnetic or soft magnetic metal plate, glass, paper, or the like. In the present invention, it is necessary to attach particles to the surface of the object 24 having the above-described material and having a complicated surface shape. In the present invention, the particles can be carried on the object surface by simply carrying the particles on a brush or a fur brush and rubbing the object surface. However, in order to stably attach particles over various objects and environments, it may be preferable to promote the adhesion of particles to the object surface by various methods. In the present invention, specific examples of the method for promoting particle adhesion include a method using magnetism and a method using electrostatic interaction.

  FIG. 2 is a diagram showing a process of loading particles using electrostatic adsorption. A process for performing processing for supporting particles on the object 24 will be described with reference to FIG.

  The process shown in FIG. 2A is a process for applying an electrostatic charge to the surface of an object using a fur brush as an electrostatic charge generating member. The surface of the object 24 has a complicated shape, and is placed on a transport device 28 such as a transport stage or a belt conveyor. When the image forming process is being performed, the transport device 28 stops the transport, and when the image formation is completed, the transport device 28 moves the object in the direction indicated by the arrow A, and performs the object 24 in the next processing process. Transport. Further, after the partial image to be formed is formed, the conveying device 28 sequentially sends the object so that the next area on the surface of the object 24 is irradiated with the laser, and conveys it to the next process after the formation process of all the images. It can also be controlled.

  A fur brush 30 is rotatably held above the object 24. In the embodiment shown in FIG. 2, the fur brush 30 is moved in the direction indicated by the arrow B in the direction in which the object moves. It rotates in the counter direction. When the object 24 is a dielectric material such as plastic film, plastic film, paper, and triboelectric charging is possible, the fur brush 30 is provided with a substance that can control charging, so-called charge controlled, etc. Can be coated. The fur of the fur brush 30 is in contact with the surface of the object 24 and imparts a desired triboelectric charge to the surface of the object 24. The rotation direction of the fur brush 30 is not particularly limited in the present invention, and the fur brush 30 can be rotated in the direction opposite to the arrow B.

  When the object 24 is a plastic material subjected to a conductive treatment such as a metal plate, a metal film, or plating, a bias potential is applied between the fur brush 30 and the object 24 instead of frictional charging, An electrostatic charge can also be applied to the surface of the object 24. In this case, the fur brush 30 can be manufactured from conductive fibers or fibers subjected to conductive treatment.

  Further, the embodiment shown in FIG. 2B is a process in which an electrostatic charge is applied to the surface of the object 24 using corona discharge as an electrostatic charge generating member. In FIG. 2B, the corona discharge device 34 is biased with respect to the object 24 by the bias power source 32 and is held at an appropriate position above the object 24. The charged particles generated by the corona discharge device 34 move to the object 24 according to the bias potential and charge the surface of the object 24.

  In the present invention, when an image with sufficient contrast can be formed only by using a fur brush or the like, it is not necessary to use an electrostatic charge generating member, but environmental stability and From the standpoint of adhesion stability, it is preferable from an industrial viewpoint to use a process for promoting the loading of particles or a member therefor.

  FIG. 3 is a diagram showing a process of a particle supply step in which particles are supported on the surface of the object 24 in the present invention. 3 (a) and 3 (b) show an embodiment in which particles are supported using an electrostatic process, and the process shown in FIG. 3 (c) uses particles to support particles. Indicates the process to be performed.

  In FIG. 3A, a fur brush 36 carrying particles is arranged as a particle supply member on the charged object 24. The fur brush 36 holds particles charged to a polarity opposite to the surface charge. The fur brush 36 rotates in the counter direction in the direction indicated by the arrow B with respect to the conveying direction of the conveying device 28, and the fur brush 36 moves the carried particles to the surface of the object 24. In this case, the fur brush 36 may be biased or may not be biased.

  In the embodiment shown in FIG. 3B, an air brush 38 used as a particle supply member is held on the charged object 24. The air brush 38 ejects particles toward the surface of the object, and supports the particles on the surface of the object 24. The airbrush 38 is connected to a container (not shown) that contains particles, and the particles are ejected from the nozzle by a pressure such as air. In the present invention, before the particles are ejected from the air brush 38, the particles are given a charge opposite to the surface charge of the object 24 and then ejected from the air brush 38. In another embodiment, a member or a coating that enables frictional charging can be applied to the nozzle of the air brush 38, and desired charging can be imparted to the particle by friction when the particle passes through the nozzle.

  Moreover, in embodiment shown in FIG.3 (c), it is embodiment used suitably when using a magnetic particle as particle | grains. In FIG. 3C, magnetic particles such as magnetic toner are magnetically applied to the surface of the object 24 using a magnet 40 such as a permanent magnet or an electromagnet installed on the opposite side via the conveying device 28 as a magnetic field forming member. Hold. In the embodiment shown in FIG. 3C, the transport device 28 is configured using a ferromagnetic material such as iron, and the object 24 is formed of a magnetic material such as a steel plate. The particles are supplied from an air brush or a fur brush and are carried on the surface of the object 24 by a magnetic force. Further, in another embodiment of the present invention, the conveying device 28 can be formed from a magnetic material. If the conveying device 28 is made of a magnetic material, the conveying device 28 and the magnet can be integrated, and even if the object 24 moves, as long as the object 24 is placed on the conveying device 28, the object Particles can be held on the surface of 24.

  Although the embodiment shown in FIG. 3C is limited to some extent by the material of the object 24, the charging process of the object 24 shown in FIG. 2 can be omitted, so that the process is simplified and the cost is reduced. Is possible. In addition, as described above, when the particles can be sufficiently adhered to the surface of the object with only a fur brush or the like and can be supported, the particle adsorption treatment by the magnet or electromagnet described in FIG. Is not required.

  After the treatment described with reference to FIG. 3, particles adhere to the surface of the object 24 by electrostatic attraction or magnetic force. In this state, an image can be formed by irradiating laser light in an image shape to melt the particles at the irradiated portion and fusing the particles to the object surface. In the present invention, after the image formation process by laser irradiation, an image formed by removing particles in a non-heated area, that is, a non-image portion is developed.

  FIG. 4 is a diagram showing an embodiment of a development process in the image forming method of the present invention. In the state of FIG. 4, the object 24 is placed on the transport device 28, and an image is already formed on the object 24 in an image shape. In this case, since the particles are also attached to the non-image portion, the image is not visualized. The development process of the present invention is performed by removing particles in the non-image area. In the present invention, a contact removal method and a non-contact removal method are possible as the particle removal method. FIG. 4A shows a contact development process, and FIG. 4B shows a non-contact development process. 4A, the developing fur brush 42 as a particle removing member is arranged on the upper portion of the object 24 placed on the conveying member 28 so as to be in contact with the object 24. As shown in FIG. Yes.

  The developing fur brush 42 rotates in the counter direction with respect to the conveying direction of the object, and removes particles attached to the surface of the object 24 as it rotates. On the other hand, since the particles in the image portion are fused to the surface of the object 24 by laser irradiation, they are not removed from the object surface even if they are rubbed by the developing fur brush 42. As a result, the formed image is developed. The In the present invention, a bias potential may be applied to the development fur brush 42 in order to adjust the development efficiency. In addition, in order to perform optimal development, the material, physical properties, sliding pressure, and the like of the development fur brush 42 can be adjusted as appropriate to obtain optimal development conditions.

  FIG. 4B is a diagram showing an embodiment of a non-contact development process. In the non-contact developing process in the present invention, as shown in FIG. 4B, a developing air brush 44 that sprays a fluid such as water or a solvent on the upper side of the object 24 as a particle removing member according to the characteristics of air or the object. Place. The developing air brush 44 ejects a pressurized fluid toward the surface of the object 24. The particles in the non-image area are removed by the ejected fluid, and only the particles fused in an image shape to the surface of the object 24 remain on the object surface, and the development is completed. In the non-contact type development process of the present invention, the development area is shielded by a shielding member such as a shielding box so that the particles are prevented from being scattered and unused particles can be collected, and a dust collector (not shown) is provided from the inside of the shielding member. Etc. can be used to add a process for recovering excess particles.

  FIG. 5 is a process diagram showing an embodiment of the image forming method of the image forming system of the present invention. As shown in FIG. 5, in the image forming method of the present invention, the object 24 is placed on the conveying device 28, and the conveying device 28 is intermittent or in response to timing in the process. Has moved to. In FIG. 5, the object 24 in the state conveyed to the laser irradiation process and the development process after the particle adhesion process is indicated by a virtual line.

  The object 24 is supplied with particles using a fur brush or an air brush which is a particle supply member, and is subjected to a particle adhesion process. Thereafter, the object 24 is subjected to a laser irradiation process by a laser irradiation system, and particles are fused in an image shape on the object 24 by image-like irradiation in the laser irradiation process.

  Thereafter, the object 24 is conveyed into the shielding member 46 and subjected to a development process in which unfixed particles are removed by rubbing or air using a particle removing member. As described with reference to FIG. 4, the development process can be performed by contact development using a development fur brush or non-contact development using a development air brush. In the embodiment shown in FIG. 5, a dust collector 48 is connected to the shielding member 46 to collect waste particles removed from the non-image part. An image instructed by the user by the control computer 14 is formed on the surface of the object 24 that has undergone the development process, and an image is formed on the surface after final cleaning and rinsing as necessary. It is regarded as a product.

  The present invention can be suitably used in an image forming process for forming an image on the surface of an object having a complicated three-dimensional shape. However, the present invention naturally forms an image on a planar object. Can do. In this case, the object that is the object to be shaped can be a printed circuit board, a printed wiring board, an offset printing plate, and provided as a resist, mask, or halftone dot by optimizing the physical properties of the particles. It can also be used as a direct drawing system.

  Furthermore, in the present invention, by changing the physical properties of particles such as hue and material and repeating the process of particle adhesion, laser irradiation and development, it is also possible to perform image formation in which the hue and physical properties of the particles are combined. When particles having different hues are used, a desired color can be generated from dots of particles having a CMYK hue, thereby forming a full color image.

In the image forming system according to the present embodiment, the following description will be made assuming that particles are fixed to an object by irradiation with CO ₂ laser light. However, the method for fixing toner to an object is not limited to this. For example, particles can be fused to an object by irradiation with an infrared laser such as Nd-YAG laser light. If processing efficiency is not particularly required, natural light is condensed and irradiated to the particles. You may make it fuse | melt.

  Further, in the image forming system of the present invention, it has been described that a beam-shaped laser beam is scanned by a scanner and conveyed by a conveying member. However, in another embodiment of the present invention, an object is fixed and a laser beam is emitted. As an element for modulating, an optical mask can be used to form a desired pattern at a predetermined location of an object using Fourier transform. Alternatively, the coloring target member may be moved so that light is irradiated to a desired position. Laser beam scanning can also be performed using a polygon mirror or prism as a reflection mirror, and an f-θ lens can be used as a condenser lens.

  Furthermore, in the image forming system of the present invention, the excess particles are removed from the object surface by jetting fluid or fur brush, but the method for removing the excess particles from the coloring target member is limited to this. It is not a thing. For example, the removal of excess particles can be applied to particle removal by appropriately forming an attractive force or repulsive force by a magnet or an electromagnet. Similarly, an attractive force or a repulsive force can be formed and applied to the particle application process.

  Hereinafter, the present invention will be described by way of specific examples. However, the examples of the present invention are illustrative, and the present invention is not limited to the examples.

A. Image forming system and process conditions A-1. Objects and Particles for Image Formation As objects for image formation, polyethylene terephthalate (PET), acrylic resin plate, glass, paper phenol, aluminum, stainless steel, wood, glossy paper, natural rubber, and re-ethylene terephthalate (PET) with uneven surface Acrylic resin plate, aluminum and stainless steel were used. As the particles, color toner manufactured by Oki Electric Industry Co., Ltd. was used.

A-2. Image forming system As a laser device, G48-2-28S manufactured by Synrad, which is a high-frequency excitation waveguide CO ₂ laser, was used. The laser device oscillated laser light having a desired power based on a control signal input by the scanner controller. The control computer is based on object data, graphic data to be drawn, picture data including character data and color data, data such as toner type and amount, laser light conditions, etc. Thus, data acquired in advance to form an image on the object was input. The control computer controlled the scanner controller based on the input data, and the laser output and scanning speed were controlled by the scanner controller using the input data.

  In the embodiment of the present invention, DE3000 manufactured by General Scanning Co. was used as the scanner controller. The DE 3000 is a controller that scans the XYZ scanner based on a command from the control computer. Using this DE3000, it has an XYZ servo driver (EDD), a CPU board with a geometric error correction function, and an interface board (ECI), and each of the X / Y / Z axes has an image resolution of 16 bits. The drawing coordinates were specified. In addition, a control signal for ON / OFF modulation of the laser in accordance with the scanning data was output using DE3000.

Laser light is scanned by instructing the scanner optical system with a control signal from the scanner controller, irradiating the laser light emitted from the laser device to the commanded position of the object, and scanning the laser light on the object. I let you. The scanner optical system, using a General Scanning Co. CO ₂ laser scanner M2XY9.5mm head. The damage thresholds of the X and Y mirrors of this scanner optical system were 500 W / cm ² for continuous (CW) oscillation, 400 MW / cm ² for pulse oscillation (100 ns), and the mirror reflectivity was 99.5% or more. . The laser beam scanning was performed under the condition that the laser beam irradiation position and the focal position were controlled by controlling the position of the mirror and lens of the scanner optical system, and energy for image formation was obtained.

A-3. Process conditions Image formation was performed using the image forming system described above. As the toner, toner for a color printer was used, and the toner was adhered to the surface of an object with a fur brush. Thereafter, the object was fixed so that the reference position and placement direction of the object and the coordinate reference position of the scanner had a predetermined relationship. After fixing the object, information such as the color and pattern desired to be colored, and information such as the coloring conditions and laser oscillation conditions were input to the control computer, the image forming process was started, and imagewise exposure was performed with laser light.

  In the image forming process, the scanner controller controlled by the control computer controls the laser device, and controls the laser beam emitted from the laser device. In synchronization with the laser light control, the scanner controller controls the motor that moves the mirrors in the X and Y directions of the scanner optical system 4 and the linear motor that drives the lens in the Z direction. The position and beam size of the laser beam were controlled.

  When the laser light is absorbed by the toner, the light energy is converted into heat, and the temperature of the portion irradiated with the laser increases locally. As a result, the toner is melted and fused to the surface of the member, and the portion is colored in the color of the toner and identified as an image. After the image formation, the development process was carried out by removing the excess toner adhering to the object surface by the pressure of the fluid ejected from the air brush.

  In addition, examination of hue mixing was performed by applying a toner of a different hue after image formation of a toner of a predetermined hue and applying the above-described process again.

B. Image formation and its evaluation The above-described image formation system and process were examined by visually observing the formed image in which various conditions were changed to form an image. Table 1 shows the conditions of Examples 1 to 6 in which image formation was examined. The formed images are shown in FIGS.

B-1. Example 1
In Example 1, image formation on various materials was examined. In Example 1, the image formation of the present invention was studied using various flat plate materials. The result is shown in FIG. 6 (a) is glass, FIG. 6 (b) is paper phenol, FIG. 6 (c) is acrylic, FIG. 6 (d) is PET, FIG. 6 (e) is glossy paper, FIG. Fig. 6 (g) shows the results of image formation for natural rubber, Fig. 6 (g) for wood, Fig. 6 (h) for aluminum, and Fig. 6 (i) for stainless steel. The image forming conditions are as follows. FIGS. 6A to 6G show a laser power of 3.75 W, a scanning speed of 100 mm / s, a beam diameter of 0.5 mm, a number of times of irradiation, and FIGS. ) Was a laser power of 5 W, a scan speed of 100 mm / s, a beam diameter of 0.5 mm, and a single irradiation. As FIG. 6 shows, according to this invention, the favorable image was able to be formed with respect to various materials.

B-2. Example 2
As Example 2, the adaptability of the surface shape of the object was examined. In Example 2, by bending the object, the surface of the object was formed into a steep uneven shape. Fig. 7 (a) is an uneven-shaped acrylic, Fig. 7 (b) is an uneven-shaped PET, Fig. 7 (c) is an uneven-shaped aluminum, and Fig. 7 (d) is an image formed on an uneven-shaped stainless steel. The results are shown. Each condition is as follows. FIGS. 7A and 7B show a laser power of 3.75 W, a scan speed of 100 mm / s, a beam diameter of 0.5 mm, a single irradiation, and FIGS. 7C and 7D. The laser power is 5 W, the scan speed is 100 mm / s, the beam diameter is 0.5 mm, and the number of times of irradiation is one. As shown in FIG. 7, the image forming system according to the present embodiment was able to form a good image at a desired position even on an uneven object regardless of the material of the object.

B-3. Example 3
As Example 3, the relationship between the image and the number of times of laser light irradiation was examined. FIG. 8 shows the result of image formation of a line image on PET under the conditions of a laser power of 3 W, a scan speed of 100 mm / s, a beam diameter of 0.5 mm, and a line length of 10 mm. 8 (a) shows the number of times of irradiation, FIG. 8 (b) shows the number of times of irradiation of 2, FIG. 8 (c) shows the number of times of irradiation of 3, and FIG. 8 (d) shows the number of times of irradiation of 4. (E) shows the coloring result when line drawing is performed under the condition of five irradiations. As shown in FIG. 8, it can be seen that the line width and the image density increase as the number of times of laser irradiation is increased. This is presumably because a larger number of particles melted and fused as the light energy supplied to the particles increased.

B-4. Example 4
As Example 4, laser power and image formability were examined. FIG. 9 shows the result. In FIG. 9, the irradiated laser light was irradiated to PET under the conditions of a scan speed of 100 mm / s, a beam diameter of 0.5 mm, a number of irradiation times of 1, and a line length of 10 mm. 9A shows a laser power of 3.25 W, FIG. 9B shows a laser power of 3 W, FIG. 9C shows a laser power of 2.75 W, and FIG. 9D shows a laser power. FIG. 9 (e) shows the coloring result when line drawing is performed under the condition of laser power of 2.00W. As shown in FIG. 9, when the energy supply by the laser beam is increased, the line width and the density are confirmed to increase as in the embodiment shown in FIG. It was confirmed that formation was possible.

B-5. Example 5
As Example 5, the relationship between the scanning speed of the laser beam and the image formability was examined. FIG. 10 shows the result. FIG. 10 is a diagram showing the results of line marking coloring for PET under the conditions of a laser power of 22.5 W, a beam diameter of 0.5 mm, a number of irradiation times of 1, and a line length of 10 mm. 10A is a scan speed of 400 mm / s, FIG. 10B is a scan speed of 600 mm / s, FIG. 10C is a scan speed of 800 mm / s, and FIG. 10D is a scan speed of 1000 mm / s. s, FIG. 10 (e) shows a coloring result when a line image is formed under a scanning speed of 1200 mm / s. In the embodiment shown in FIG. 10, when the scanning speed is increased, a decrease in line width and a decrease in density are observed with a corresponding decrease in the supplied light energy, but a good image can be formed. I understood.

  As shown in FIGS. 8 to 10, it was shown that good images can be formed also in Examples 3 to 5 by the image forming system and method of the present invention. That is, with the coloring system of this embodiment, the line width and color density can be changed by changing the number of times of laser light irradiation to the same location, the light intensity density of the laser light, and the scanning speed of the laser light. Furthermore, the line width is very fine, and it was shown that a very delicate pattern can be drawn.

B-6. Example 6
As Example 6, mixing of colors using particles of different hues and formation of adjacent images were examined. In Example 6, PET was imaged under the conditions of laser power of 15 W, scan speed of 400 mm / s, beam diameter of 0.5 mm, number of times of irradiation, and line length of 10 mm. FIG. 11A shows a case in which line drawing is performed by applying cyan, FIG. 11B applying magenta, and FIG. 11C applying yellow toner. 11 (d) shows cyan and magenta, FIG. 11 (e) shows magenta and yellow, and FIG. 11 (f) shows a case where mixed toner of yellow and cyan is applied to perform line drawing. FIG. 11H shows cyan toner in the magenta already colored portion, FIG. 11I shows yellow toner in the magenta already colored portion, and FIG. ) Shows magenta toner on the yellow colored area, FIG. 11 (k) shows cyan toner on the yellow colored area, and FIG. 11 (l) shows yellow drawing on the cyan already colored area. The result of performing is shown.

  Similarly, FIG. 11 (m) shows magenta near the cyan colored area, FIG. 11 (n) shows yellow near the magenta colored area, and FIG. 11 (o) shows cyan toner near the yellow colored area. The coloring results are shown in the case where two lines are drawn for each color alternately and a total of four lines are drawn.

  As shown in FIG. 11, it can be seen that the image forming method of the present embodiment enables good color mixing without color unevenness. Further, in the present invention, the hue can be changed by a method of mixing a plurality of colors of toner, a method of coloring a plurality of colors of toner in a superimposed manner, or a method of arranging a plurality of colored portions in the vicinity, It was shown that the width of the line is very fine and that a very delicate pattern can be drawn.

B-7. Example 7
As Example 7, the coloring density with respect to the irradiation energy density of the laser in the coloring system of the present embodiment for the acrylic member was measured. The integrated energy of laser irradiation was measured using 300W-HP (manufactured by OPHIR, JLP-300W-HP manufactured by Japan Laser). The image was taken in as a digital image and measured using image software (Photoshop (registered trademark) manufactured by Adobe). FIG. 12 shows a comparison of the color density with the irradiation energy density of the laser for the image forming method using the LPC method as a comparative example, together with the coloring state. As shown in FIG. 12, the image obtained by the image forming system of the present invention has a maximum color density of about 10 times the maximum color density in the LPC color system.

  Furthermore, it was found that the irradiation energy density that can be colored in the image forming system of the present invention can be about 0.1 times the irradiation energy density that can be colored in the LPC coloring system. From these facts, it was shown that the image forming system of the present invention enables energy-saving and efficient coloring.

  Further, when the coloring state with respect to the irradiation energy density in the LPC method coloring system as a comparative example is seen, it can be seen that the LPC method coloring system requires a lot of energy until the rise of the image density. This can be considered that in the LPC method, the surface of the object is first modified, and the traces are colored. That is, it can be seen that in the LPC method, the modification and coloring of the object surface are performed simultaneously.

On the other hand, as a result of the colored state obtained in the examples of the present invention, an image having a visible density can be formed by supplying light energy of approximately 0.5 J / cm ² or more. When the system is in the range of 0.5 to 1.3 J / cm ² , it is possible to form an image with no marks of processing or modification remaining on the surface of the acrylic object. For this reason, the state before coloring can be restored by removing the coloring. I found it possible. Furthermore, in the present invention, it can be seen that a robust image can be formed by irradiating light energy of 1.3 J / cm ² or more from the viewpoint of the fastness of the image.

B-8. Example 8
As Example 8, the cross-sectional density distribution of dot coloring in the coloring system of the present embodiment for an acrylic member was examined. The results are shown in FIG. 13 together with the dot concentration cross-sectional density distribution in the LPC coloring system as a comparative example. The vertical axis represents the relative value of the density of the image obtained by the present invention, and the horizontal axis represents the relative position in the radial direction of the dot. The concentration was measured using the measurement method used in Example 7. The cutting line in the radial direction is also shown on the right hand side of FIG.

  As shown in FIG. 13, the density distribution of the LPC method coloring system, which is a comparative example, is non-uniform, low density, and gently spreads to the periphery, whereas the image obtained by the present invention is It can be seen that the density distribution is uniform, the density is high, and the density contrast from the periphery is extremely high. This is because the coloring in the LPC method coloring system as a comparative example was low contrast, low density, and a relatively large minimum coloring unit, whereas coloring in the image forming system of the present invention was high contrast, This indicates that high concentration and fine coloring are possible.

  According to the present invention, it is possible to provide an image forming system and an image forming method capable of selectively performing desired coloring at desired positions on members of various materials and complicated shapes. It can be applied to a stereoscopic color printer suitable for direct drawing by a laser. The present invention can be widely applied in the field of image formation such as spot printing field, printed wiring field, planographic printing field, logo printing, and printing on character products.

1 is a block diagram of an image forming system of the present invention. The figure which showed the process of the electrostatic charge provision process of this invention. The figure which showed the process of the particle | grain supply process of this invention. The figure which showed the process of the particle removal process (development process) of this invention. FIG. 4 is a process diagram illustrating the image forming process of the present invention in the order of element processes. The figure which showed the image obtained by the Example of this invention. The figure which showed the image obtained by the Example of this invention. The figure which showed the image obtained by the Example of this invention. The figure which showed the image obtained by the Example of this invention. The figure which showed the image obtained by the Example of this invention. The figure which showed the image obtained by the Example of this invention. The figure which showed the image obtained by the LPC method as a comparative example about the density and coloring state of dot coloring in the image forming system of this invention with respect to an acrylic member. The figure which showed the image obtained by LCD method as a comparative example about the cross-sectional density distribution of the dot coloring in the image forming system of this invention with respect to an acrylic member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Image forming system, 12 ... Laser apparatus, 14 ... Control computer, 16 ... Scanner controller, 18 ... Scanner optical system, 20 ... Condensing lens, 22 ... Reflecting mirror, 24 ... Object, 26 ... Fusion image, 28 DESCRIPTION OF SYMBOLS ... Conveying device, 30 ... Fur brush, 32 ... Bias power supply, 34 ... Corona discharge device, 36 ... Fur brush, 38 ... Air brush, 40 ... Magnet, 42 ... Fur brush,
44 ... Air brush, 46 ... Shielding member, 48 ... Dust collector

Claims (15)

An image forming system for forming an image on the surface of an object,
A particle supply member for supplying thermoplastic particles to the surface of the object;
A light irradiation system for irradiating and melting the particles carried on the surface of the object, and fusing the particles in an image form on the surface of the object;
An image forming system comprising: a particle removing member that removes particles not fused to the surface from the surface of the object.   The image forming system according to claim 1, wherein the object is a three-dimensional object, and the surface of the object has a non-planar shape.   The image forming system according to claim 1, wherein the light irradiation system includes a laser device and an optical system that modulates laser light from the laser device into an image.   The image forming system according to claim 1, wherein the optical system includes a light reflecting element or an optical mask.   The image forming system according to any one of claims 1 to 4, further comprising an electrostatic charge generating member or a magnetic field forming member for promoting the loading of the particles on the surface of the object. An image forming method for forming an image on the surface of an object using an image forming system,
Supplying an object to the imaging system;
Supplying thermoplastic particles from the particle supply member to the surface of the object;
Performing imagewise exposure from a light irradiation system, irradiating and melting the particles carried on the surface of the object, and fusing the particles imagewise to the surface of the object;
And a step of removing particles not fused to the surface from the surface of the object by a particle removing member.   The image forming method according to claim 1, wherein the step of supplying the object provides a three-dimensional object in which the surface of the object has a non-planar shape.   The image forming method according to claim 6, wherein the step of fusing includes a step of modulating laser light from a laser device into an image using an optical system. The image forming method according to claim 6, wherein the step of fusing includes a step of supplying light energy of 0.5 J / cm ² or more to the particles and fusing the particles.   The image forming method according to claim 9, comprising a step of changing the line width and density of the image by changing the light energy.   The image forming method according to claim 6, further comprising a step of accelerating the holding of the particles on the surface of the object by an electrostatic charge generating member or a magnetic field forming member before the supplying step.   The step of supplying includes a step of rubbing a surface of the object by the particle supply member, a step of spraying the particles on the surface of the object, or a step of supplying the particles by electromagnetic interaction. The image forming method of any one of -11.   The step of removing includes a step of rubbing the surface of the object by the particle supply member, a step of spraying a fluid on the surface of the object, or a step of removing the particles by electromagnetic interaction. 12. The image forming method according to any one of 11 above. Further attaching particles of different hues on the object to the formed image;
The image forming method according to claim 6, further comprising: fusing the adhered particles having different hues with the laser beam and mixing the hues of the already formed image with hues.   15. The particle according to claim 6, wherein the particle includes colored particles having different hues, and the step of fusing includes mixing the colored particles having different hues on the surface of the object by the laser irradiation. 2. The image forming method according to item 1.

Images