JP6181028B2 - Heating head - Google Patents

Description

  The present invention relates to erasing and writing of a record on a heat-sensitive rewritable medium, transfer and retransfer to a medium, toner fixing, adhesion by heating, fusing, deformation processing, overcoat, document laminating, sheet adhesion, The present invention relates to a heating head having a belt-like heating resistor for heating a medium in order to perform imprint processing (uneven heat processing such as plastic). More specifically, the present invention relates to a heating head capable of heating while protecting the surface of the heating resistor formed on the head substrate without directly pressing the surface.

  In recent years, for example, reversible coloring and decoloring by heating on a film, sheet, card or other support made of synthetic resin such as paper, non-woven fabric, woven fabric, vinyl chloride, polyethylene terephthalate, metal, glass, etc. Heating heads are used in a wide range of fields, such as reversible thermosensitive recording media (rewritable cards and rewritable sheets) with reversible thermosensitive recording layers that can be repeated, and overcoats, undercoats, and sealing of plastic bags. It has come to be.

  As a heating head for heating such a medium, for example, a heating resistor is provided in a belt shape on one surface of a head substrate made of ceramic such as rectangular alumina, and a voltage is applied to both ends to generate heat from the heating resistor. In addition, recording and erasing are performed by heating the above medium while pressing the medium.

  As described above, it is preferable to transport the medium while pressing the medium on the surface of the heating resistor because it is in direct contact with the heating resistor so that heat conduction is fast and there is no waste of heat. However, since the medium slides on the surface while being pressed, the heating resistor is severely damaged. Therefore, a protective film for protecting the heating resistor by forming a glass coat on the surface of the heating resistor is formed. However, the glass coat is also very worn and severely damaged. Therefore, a heating head has been proposed that heats a surface on which a heating resistor is not provided, such as a surface opposite to a surface on which a heating resistor is provided on a head substrate, as a pressure contact surface with a medium (see, for example, Patent Documents 1 and 2). ).

  That is, as shown in FIG. 8, the heating resistor 2 is formed on one surface of the head substrate 1, and the heating formed by being fixed to the base 4 through the heat insulating spacer 6 c, the heat insulating plate 6 and the wiring substrate 5. A head 10 is formed. Then, the surface of the head substrate 1 on which the heat generating resistor 2 is not formed, for example, the back surface side is set so as to be pressed against the platen 32, the medium 31 is inserted therebetween, and the medium 31 is rotated by the rotation of the platen 32. Is conveyed while being pressed against the heating head 10. The platen 32 is composed of a surface layer 32a made of heat-resistant rubber such as fluorine rubber, an interior 32b made of heat-insulating rubber such as silicone rubber or fluorine rubber, and a rotating shaft 32c, and has elasticity. May be formed.

JP 2010-208159 A JP 2011-016334 A

  As described above, when a medium is heated by using a heating head, the heating resistor is not rubbed at all by using the surface where the heating resistor is not provided as the pressure contact surface, so that it is not damaged. In addition, ceramics such as alumina that are usually used as a head substrate have a high hardness, and even if the medium is pressed against and rubbed with the medium, it is hardly damaged and the durability of the head substrate is greatly improved. However, there are various media such as plastic cards, paper, and resin films forming a plastic bag, and there are various heating purposes. For example, if the medium is conveyed while pressing the back surface of the head substrate 1 on the surface of a medium such as a card or a card having a waxed surface on a plastic or cardboard, there is a problem in that the medium is longitudinally damaged and the commercial value is lowered. In addition, there is a problem that it cannot be applied to heating of various media, such as when it is desired to partially heat the media or when it is desired to apply different heating conditions for each region with one media.

  Thus, with the advent of various media, more suitable heating conditions are various, and development of a heating head according to these heating conditions is urgently required. In other words, if you want to heat media with different heating conditions in the media material and media width direction, platen material, media moving speed (heating speed), pressure during contact heating, non-contact heating, etc. Depending on the specifications of the medium and peripheral members and the heating conditions, it is necessary to diversify the heating characteristics of the heating head, and a heating head more suitable for each medium and heating apparatus has been desired. However, the conventional heating head cannot be adjusted to meet various heating conditions, and it is necessary to regenerate the heating resistor or the like according to the conditions, which leads to inefficiency and high cost.

  The present invention has been made in view of such circumstances, and the pressure contact surface with the medium of the heating head that is heated in contact with the medium is defined as a surface on which the heating resistor is not formed. It is an object of the present invention to provide a heating head provided with a covering material so as to be in a heating condition more suitable for a medium to be heated in relation to the material and specifications of peripheral members.

  The inventors of the present invention have made extensive research in order to efficiently realize a heating head suitable for these various heating conditions, as the heating conditions differ depending on the type of medium, the type of platen, and the heating method. One surface of the head substrate on which the resistor is not formed is used as a heating surface (pressure contact surface) for heating the medium, and surface processing (hereinafter referred to as surface processing to make a mirror surface or a rough surface by grinding or cutting, By applying "surface processing" including surface treatment such as chemical cleaning and overcoat, etc., the heating characteristics can be adjusted and changed in various ways, and a heating head suitable for various heating conditions can be efficiently used. Found that can be provided.

  In other words, when the surface of the head substrate on which the heating resistor is formed is used as a heating surface for the medium, the processing or processing conditions are greatly limited by the presence of the heating resistor, When the covering layer is formed on the head substrate surface on which the resistor is not formed, for example, the forming process of the covering layer is easy, and various types of materials can be used regardless of organic materials, inorganic materials, insulating materials, and conductive materials. An overcoat material can be used, and the heating characteristics can be controlled in various ways. More specifically, for example, when heating a medium that is easily scratched, the ceramic head substrate is hard and has irregularities of alumina particles on its back surface, and is easily damaged when pressed. Therefore, the medium can be prevented from being damaged by overcoating one surface, which is the pressure contact surface, with an elastic resin layer and a low friction metal sheet. In this way, thermal conductivity, heat retention, releasability (peelability), friction, elasticity, smoothness, by changing the physical properties of the overcoat, or changing its thickness and surface state, Various characteristics such as lubricity, thermal responsiveness, temperature responsiveness, heat capacity characteristics, foreign matter adhesion prevention, low friction, wear resistance, adhesion, heat capacity, heat resistance, etc. can be controlled.

That is, the heating head of the present invention includes a plate-like head substrate, at least one belt-like heating resistor provided on one surface of the head substrate, and a pair of electrodes provided so that a voltage can be applied to the heating resistor. One surface of the head substrate on which the heating resistor is not provided is a pressure contact surface with the medium, a coating layer is deposited on the one surface, and the coating layer is formed on the one surface of the head substrate. It is formed longer than the length in the moving direction of the medium, and the end of the covering layer is bent toward the head substrate at the end of the one surface .

  In the present invention, the term “deposition” means that a film is formed by plating or vapor deposition, a film is formed on the surface by coating and drying of a coating agent, etc., and a plate or sheet is adhered by an adhesive or the like. That means that the coating layer is formed in close contact with one surface of the head substrate or the like. In addition, surface processing means, for example, when the head substrate is a ceramic substrate, the ceramic surface, which is the pressure contact surface, is processed into a mirror or rough surface by various polishing, lapping, sand blasting, cutting, etc., or irregularities are formed. In addition, the edge of the ceramic substrate is raised, the C surface and the R surface are chamfered, and the ceramic surface is coated with various materials such as organic materials, inorganic materials, insulating materials, and conductive materials. Or a surface treatment such as washing with various chemicals. In the present invention, these ground treatment and surface treatment may be combined.

  Examples of organic materials used for the overcoat include fluorine resins such as polytetrafluoroethylene (PTFE), polyamide resins such as nylon, olefin resins such as polyethylene (PE), polyether ether ketone (PEEK), and poly Known resin materials such as engineering plastics such as ether sulfone (PES), silicone, etc. can be widely cited, and one or more of these organic materials can be used in combination, and various additives such as fillers and impurities can be used. In addition, it can be used. Moreover, these resin materials can provide a heating head having more various heating characteristics by containing conductive materials such as metal particles and metal powder.

  As a method of overcoating the resin material on the ceramic surface, for example, it can be performed by adhering by applying or spraying, drying, and baking as necessary. More specifically, in the case of overcoating with a fluororesin, for example, PEEK is sprayed on the ceramic surface as a base material, dried and baked, and then PTFE is sprayed in the same manner, dried and baked. Can be overcoated with a fluorine-based resin. The film thickness of the overcoat may be appropriately determined according to desired heating conditions, and may be several μm to several tens of μm, for example, or more. In addition, the overcoat layer may be formed by attaching a resin film, a resin sheet, or a resin plate using an appropriate adhesive as necessary.

  When an organic material such as a resin is used as an overcoat material, it can be generally controlled to have low friction, low adhesion, high releasability, and high elasticity.

  Examples of inorganic materials include glass, graphite-based carbon, molybdenum disulfide, barium titanate, ruthenium oxide, alumite, and other metal oxides, aluminum, aluminum-based alloys, copper, copper-based alloys, stainless steel (SUS), silver, Known metals such as nickel and chromium, alloys, and the like can be listed, and one or more of these can be used. These inorganic materials can also be used in combination with organic materials. Many conductive materials such as metals have physical properties different from those of insulating materials such as resin materials and glass. By providing an overcoat layer using such a conductive material, the heating characteristics of the heating head can be further improved. Various changes can be made.

  Glass can be applied and fired, for example, and can be overcoated. Metals and alloys are, for example, plate, sheet, and film, suitable adhesives, adhesives, and conductive adhesives. An overcoat can be formed by depositing, vapor-depositing, electroless plating, electroplating, or pasting, drying, and baking a paste-like material. Moreover, the unevenness | corrugation of a ceramic surface may be made flat by coating so that powder of overcoat materials, such as glass powder and a metal powder, may be rubbed against a ceramic surface. The film thickness of the overcoat in this case may be appropriately determined according to desired heating conditions, and may be several μm to several hundred μm, for example, or more.

  In the present invention, when an overcoat is provided on the pressure contact surface (ceramic surface), an overcoat layer may be formed after performing a surface treatment to make the ceramic surface a mirror surface or a rough surface. The adhesion of the overcoat layer can be improved. In addition, the overcoat layer may be formed after the edge of the pressure contact surface is sharpened or chamfered, and in this case, for example, the medium can be smoothly introduced between the platen and the platen. The medium can be moved in good pressure contact. Furthermore, when a thin plate of metal, alloy or the like is applied to the ceramic surface as an overcoat, the medium can be smoothly placed between the platen and the platen by extending it from the edge of the ceramic surface. Can be introduced.

  Further, for example, surface processing can be performed by laminating a resin layer and a metal thin plate (each having a thickness of about 100 μm).

  When these inorganic materials are used as an overcoat material, they can be generally controlled to have high smoothness, low friction, high thermal conductivity and the like.

  Furthermore, in the present invention, an overcoat having physical properties that are partially different from each other in the direction perpendicular to the traveling direction of the medium on the pressure contact surface may be applied. For example, an overcoat made of a resin layer is formed on the right side, an overcoat made of a metal layer is formed on the left side, or an overcoat made of a resin layer is formed on the center, and an overcoat made of a metal layer is formed on both ends. By forming, different heating conditions can be set for each region of the heating head, and various patterns of heating conditions can be realized with one heating head.

  In the present invention, a ceramic thin plate (sub-substrate) is adhered to a surface of a ceramic substrate (head substrate) on which a heating resistor is formed with a glass or resin adhesive, and the sub-substrate other than the surface to which the sub-substrate is adhered. A heating head in which the surface is a pressure contact surface and the sub-substrate is subjected to surface processing is also included.

  The thickness of the sub-substrate is not particularly limited, and is preferably about the same as or less than that of the head substrate, for example.

  In this case, if a sub-substrate adjusted in advance to various heating conditions by surface processing is prepared, the manufacturing can be easily and efficiently performed simply by adhering to the common head substrate on which the heating resistor is formed. .

  Hereinafter, one specific example of the present invention will be described in more detail. Depending on the medium, foreign matters such as lipids, adhesives, dust, and dust may be transferred to the heating head. If such foreign matter adheres to the heating head, the next time a clean medium is inserted, the foreign matter is retransferred to the clean medium, or the temperature of the part where the foreign matter has adhered is shifted from the desired temperature and normal. May not be able to perform proper heating. For this reason, it is preferable that foreign matters do not adhere as much as possible to the heating head for heating such a medium. From such a viewpoint, it is preferable that a resin film such as a fluorine-based resin such as polytetrafluoroethylene (PTFE) is attached to the heating surface of the heating head or coated to form a coating film. In addition, by overcoating the resin, the surface of the heating surface can be made softer than the ceramic surface, the lubricity can be improved, and damage to the medium surface can be reduced. That is, in the past, the heated surface was thought to require wear resistance and high hardness, but as a result of the present inventors' research, it is preferable to coat such a resin overcoat depending on the medium. In some cases.

  Further, when the reduction in thermal conductivity is reduced and surface smoothness, abrasion resistance, etc. are required, it is preferable to use a metal or an alloy for the overcoat. Note that if the thickness of the metal layer is made thinner than the thickness of the head substrate, even if there is a difference in thermal expansion from the head substrate, it is hardly affected.

  As a medium to which the heating head of the present invention can be applied, for example, paper (including cardboard), non-woven fabric, woven fabric, vinyl chloride, polyethylene terephthalate or other synthetic resin, metal, glass, or the like, A reversible thermosensitive recording medium (rewritable card) provided with a recording portion comprising a reversible thermosensitive recording layer capable of reversibly repeating coloring and decoloring by heating on a card-like or plate-like material, and a support made of the material. Rewritable sheets), recording paper used for transfer, retransfer, toner fixing, etc., base film, and the above materials that perform adhesion, fusion, deformation, overcoat, undercoat, laminating, imprinting, etc. by heating And so on. In addition, the heating surface of the heating head of the present invention is a surface for heating a medium such as a recording medium, and can be heated by being brought into contact (pressure contact) with the medium or heated in a non-contact manner.

  In the present invention, when surface processing is performed on the surface of the head substrate on which the heating resistor is not provided, a ceramic substrate is provided on the surface of the head substrate on which the heating resistor is provided so as to cover the heating resistor. You may make it stick with sticking materials, such as glass paste. By doing in this way, a heating resistor can be protected, handling when attaching an electric wiring etc. or incorporating in a heating device can be facilitated, and a heat capacity can be increased.

  In the present invention, the surface treatment is performed to form one or more overcoat layers of an insulating material and a conductive material, or an organic material and an inorganic material. At this time, the overcoat layer may be provided so as to protrude from the surface on which the overcoat layer is formed, or may extend to a surface adjacent to the surface on which the overcoat layer is formed. You may form as follows.

  In the present invention, when an overcoat layer is provided on the surface of the head substrate where the heating resistor is not provided, or on the outer surface of the sub-substrate, the surface of the head substrate where the heating resistor is not provided, or over the outer surface of the sub-substrate. You may make it interpose a liquid layer, such as gas layers, such as air and various gas, various aqueous solutions, and various oils, between coat layers.

  In the present invention, the surface processing includes deposition of a coating layer on one surface of the head substrate or the sub-substrate, and a ground processing for performing processing on one surface of the head substrate or the sub-substrate on the lower surface of the coating layer. This surface treatment depends on the specifications of the heating medium, heating device, etc., thermal conductivity, heat retention, releasability, friction, elasticity, smoothness, lubricity, thermal response, temperature reactivity, heat capacity Considering characteristics, foreign matter adhesion prevention, low friction, abrasion resistance, adhesion, heat capacity, heat resistance, etc., the types of overcoat materials, their combinations, thicknesses, formation locations, The formation region (range) can be selected and performed.

  As the surface processing, for example, metal powder or glass powder may be coated in order to improve the smoothness by flattening the unevenness of the surface (heating surface) of the head substrate or sub-substrate.

  As the surface processing treatment, for example, a glass coat layer may be applied to the surface of the head substrate or the sub-substrate.

  As the surface processing, for example, a fluorine-based resin film may be formed on the surface of the head substrate or the sub-substrate.

  As the surface processing, for example, a metal sheet may be attached to the surface of the head substrate or the sub-substrate.

  As the surface processing, for example, a metal sheet and a fluororesin coating may be deposited and formed in this order or in reverse on the surface of the head substrate or sub-substrate.

  The covering layer is formed to be longer than the length of the one surface of the head substrate or the sub substrate in the moving direction of the medium, and the end of the covering layer at the end of the one surface is on the side of the head substrate or the sub substrate. It is preferable to be bent. It is easy to move the medium smoothly between the heating head and the platen.

  The covering layer is formed shorter than a length of the one surface of the head substrate or the sub-substrate in the moving direction of the medium, and an end portion of the covering layer on the medium intrusion side is formed on an R surface or a C surface. Preferably it is. This is because the medium can be easily inserted.

  The base treatment applied to the one surface of the head substrate or the sub-substrate may be formed on an R surface or a C surface formed at an end portion of the one surface on the entry side of the medium.

  The coating layer may be formed of different materials by being divided into two or more regions with a length in a direction perpendicular to the intrusion direction of the medium. Different heating can be performed depending on the area of the medium, and various heating can be performed.

  As the ground treatment under the coating layer, for example, ground treatment such as mirror surface, rough surface, uneven formation, and chamfering may be performed.

  The coating layer may form two or more different overcoat layer regions.

  According to the heating head of the present invention, the pressure contact surface with the medium is a surface on which no heating resistor is provided, and the coating layer is formed on the surface. A heating head having a heating characteristic can be produced, and a heating head more suitable for the heating characteristics required according to the specification (type) of the medium or the specification of the heating apparatus can be provided. That is, as a conventional heating head, a protective film is formed on the surface of the heating resistor formed on the head substrate, and this surface is used as a pressure contact surface, but the material used as the protective film is limited. When changing the heating characteristics of the heating head according to the specifications of the medium or heating device, the only way to change the resistance value is to change the type (component) or thickness of the heating resistor, and the thermal conductivity, heat retention, Fully releasability, friction, elasticity, smoothness, lubricity, thermal responsiveness, temperature responsiveness, heat capacity characteristics, foreign matter adhesion prevention, low friction, wear resistance, adhesion, heat capacity, heat resistance, etc. Could not be controlled. According to the present invention, since surface processing is performed on the surface of the head substrate or the surface of the sub-substrate that is not provided with the heating resistor, various base treatments and overcoat materials can be applied, Just by changing the surface processing method, various heating characteristics and heating conditions can be created, a heating head more suitable for the medium and the heating device can be provided, more efficient heat treatment can be realized, It can meet the demands of various users.

  Also, a sub-board made of ceramics of the same material as the head substrate is attached to the surface of the heating resistor of the heating head, and the surface other than the surface to which the sub-substrate is attached is used as a pressure-contact surface with the medium. Since the surface processing can be performed in the state of the sub-substrate in advance, the heating head can be formed by forming the surface processing sub-substrate for various purposes. At the time of formation, a sub-substrate is attached to the surface of the heating resistor of the head substrate with glass paste or the like, so that a heating head corresponding to the processing of the medium can be easily formed as needed.

It is a section explanatory view showing one embodiment of a heating head of the present invention. It is sectional explanatory drawing which shows other embodiment of the heating head of this invention. It is sectional explanatory drawing which shows another embodiment of the heating head of this invention. It is explanatory drawing of the circuit which measures the temperature of a head board | substrate using a heating resistor. It is sectional explanatory drawing which shows the modification of the heating head of this invention. It is sectional explanatory drawing which shows the other modification of the heating head of this invention. It is explanatory drawing which shows another modification of the heating head of this invention. It is explanatory drawing in the case of heating a medium using the conventional heating head.

  Next, the heating head and heating method of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional explanatory view perpendicular to the longitudinal direction of the heating head according to the present invention. Although a plan view is not shown, as shown in FIG. 3A, a plan view of another embodiment is shown, the planar shape is rectangular, and the heating resistor 2 is formed along the longitudinal direction, A pair of electrodes are formed at both ends, and can be energized. In the example shown in FIG. 1, four heating resistors 2 are formed, and only one heating resistor 2 is shown in FIG. 3A, but the number of heating resistors 2 is not limited. One of these may be used for temperature measurement.

  The heating head 10 of this embodiment shown in FIG. 1 is provided with at least one belt-like heating resistor 2 on one surface of a plate-like head substrate 1 so that a voltage can be applied to both ends of the heating resistor 2. In addition, a pair of electrodes (not shown) are electrically connected. Any one of the surfaces of the head substrate 1 on which the heating resistor is not provided is formed as a surface 1a that is pressed against the medium so as to be exposed to the outer surface, and a coating layer (over layer) is formed on the one surface 1a that is pressed against the medium. Coat layer) 8 is formed. In FIG. 1, reference numeral 4 denotes a base, and 5 denotes a wiring board connected to the above-described pair of electrodes so as to be supplied with power, and a head is provided on the surface via a heat insulating plate 6 and a heat insulating spacer 6c. The substrate 1 is fixed. By interposing the heat insulating spacer 6c, the periphery of the heating resistor 2 is exposed to the space, and the heat flow by heat conduction is exclusively on the head substrate 1 side, and the one surface 1a of the head substrate 1 is sufficient. Furthermore, since the head substrate 1 has a thickness of about several millimeters, it has a certain heat capacity. Therefore, even when the medium comes into contact with the head substrate 1, the temperature does not drop suddenly, and stable heating can be performed. The present embodiment is characterized in that a coating layer 8 is formed on one surface 1a of the head substrate 1 that is in pressure contact with the medium. The covering layer 8 will be described later. Instead of the wiring board 5, an electric wire may be connected to a pair of electrodes and the wiring may be pulled out. Instead of the heat insulating spacer 6c, the heating resistor 2 forming surface of the head substrate 1 may be You may make it stick on the heat insulation board 6 with adhesive materials, such as a glass paste and a resin adhesive material.

  FIG. 2 is an explanatory sectional view similar to FIG. 1 of another embodiment of the present invention. That is, in this embodiment, the surface opposite to the surface on which the heating resistor 2 of the head substrate 1 is provided is fixed to the wiring substrate 5, and the surface of the heating resistor 2 is made of a ceramic material such as alumina similar to the head substrate 1. The substrate 11 is bonded, and the surface 11a opposite to the bonding surface is a pressure contact surface with the medium, and the coating layer 8 is formed on the surface. The sub-substrate 11 may be made of the same material as the head substrate, and may have the same thickness, but the thickness may be thinner than the head substrate 1. In addition, it is desirable that a heat insulating adhesive is used for adhering the head substrate 1 and the wiring substrate 5. This is to eliminate waste of heat.

  Further, in the embodiment shown in FIG. 3, the head substrate 1 on which the heating resistor 2 is provided on one surface is provided on the base 4 via the first heat insulating plate 6a, and the second is formed by the holding plate 9a and the screw 9b. It is attached to the base 4 with the heat insulating plate 6b interposed therebetween. Although not shown in FIG. 3A, a coating layer 8 is formed on the side surface so as to protrude from the side surface and extend downward (see FIGS. 3B and 3C). As shown in FIG. 3C, the heating head 10 is configured to be pressed by a platen 32 while the medium 31 passes over the coating layer 8 on the side surface 1 b of the head substrate 1. Even in such a heating device, the medium 31 can be heated while being smoothly transported by utilizing the characteristics of the coating layer 8. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. Further, in the example shown in FIG. 3, the wiring substrate 5 is formed of a flexible film and is provided under the presser plate 9a. However, the structure shown in FIG. Further, instead of the (roller) platen 32, a flat platen can be used by using a transport mechanism such as a roller for transporting the medium 31 separately.

  In the structure in which the side surface 1b of the head substrate 1 is a pressure contact surface, the heating resistor 2 is not provided on only one surface of the head substrate 1, but is also provided on the lower side of the head substrate 1 in FIG. It can also be provided. By adopting such a structure, the temperature of the head substrate 1 can be increased even if the heat generation amount of one heating resistor 2 is reduced, and stable heating can be performed.

  The embodiment shown in FIGS. 1 to 3 shows an example in which the surface that is in pressure contact with the medium is different. In short, as long as the heating resistor 2 is not formed, the back surface or the side surface of the head substrate 1 may be used. When the sub-board 11 is bonded, any surface other than the bonding surface, such as a surface opposite to the bonding surface or a side surface thereof, can be the pressure contact surface.

  The covering layer 8 can be formed in various forms. That is, as described above, as a result of extensive studies by the present inventors, it has been found that the pressure contact surface of the heating head is preferably optimized in accordance with the type of medium and the purpose of heating. . Various aspects thereof will be described below. In any case, a surface other than the surface on which the heating resistor 2 of the heating head is provided is a pressure contact surface, and the surface of the pressure contact surface is processed. The coating layer 8 is characterized by being formed.

  When these coating layers are provided, the thicker the coating layer 8, the longer it takes to conduct heat, and the adhesion with the head substrate or the like may be reduced depending on the type of the coating layer 8. The layer to be applied is preferably within a range of an appropriate thickness, including a case where a plurality of layers are formed.

  As described above, the head substrate 1 or the sub substrate 11 is formed of ceramics such as alumina. Therefore, the hardness is large and firm, but the surface has many fine irregularities. Therefore, if the medium is heated while being pressed and conveyed between the heating head and the platen, the speed cannot be increased or the surface of the medium is likely to be damaged. Therefore, it may be desired that the surface of the pressure contact surface is smooth and has low friction.

  As such a smoothing processing, it is only necessary to polish the portion to be the pressure contact surface of the head substrate 1 or the sub-substrate 11, but as described above, alumina has a high hardness and is smoothed by polishing. Attempting to do so increases the cost. Therefore, the surface processing for smoothing of the present invention is performed.

  First, the first method is to embed glass or metal in the concave portions of fine irregularities on the surface of the ceramic. As the method, first, in the case of glass powder, a glass layer may be formed by applying and applying a glass paste of about several tens of μm, followed by sintering. Since the surface of the glass layer is smoother than the surface of the ceramic and the hardness is also lower than that of the ceramic, even if the medium is heated by the pressure contact method, damage to the surface of the medium can be reduced. Moreover, since the low friction property can be exhibited with respect to a general medium, the surface of the medium is hardly damaged. Even if the glass layer is worn out by repeated use, the smoothness can be maintained in a state where the glass has entered the concave portions of fine irregularities on the ceramic surface.

  In addition, when embedding the concave portions of fine irregularities with a metal, for example, a metal thin film (metal) of about several tens of μm is formed on the surface of the ceramic as the pressure contact surface by vacuum deposition, sputtering, electroless plating and electroplating, etc. Layer) can be formed. If necessary, the surface of the formed metal layer may be polished. The surface of the metal layer is smoother than the surface of the ceramic, and even if the medium is heated by the pressure contact method, it is possible to reduce the scratches on the surface of the medium. As a result of intensive studies by the present inventors, even if ceramics and a material having different coefficients of thermal expansion, such as a metal film, are bonded, the thickness of the metal layer is the head substrate 1 or the sub substrate 11. If the thickness is smaller than the thickness of the film, it is confirmed that there is no problem because no peeling or cracking occurs due to the difference in thermal expansion coefficient. As a result, in this case as well as the glass layer, there is no problem even if a metal coating layer is formed on the ceramic, and even if the metal layer is worn, the surface of the ceramic layer that appears below it is Since the unevenness is flattened, no problem occurs.

  As a second method, an overcoat layer (coating) is applied by directly attaching a thin metal plate of about 200 μm or less with an appropriate adhesive (for example, glass or resin) without performing a ground surface treatment (planarization process) on the ceramic surface. A layer 8) can also be provided. As described above, if the thickness of the metal thin plate is equal to or less than the thickness of the head substrate 1 or the sub-substrate 11, problems such as peeling or warping may not occur so much even if the thermal expansion coefficient differs from that of ceramics. It has been confirmed. Therefore, if it is such a thin metal sheet, there is no problem even if it is directly applied, and it is possible to exhibit heating characteristics according to the physical properties of the metal. As the metal thin plate, for example, aluminum, aluminum alloy, copper, copper alloy, surface processed metal thin plate, for example, aluminum alloy alumite, black alumite, copper, copper alloy surface is plated with Ni, Cr A thin plate can be used. These thin metal plates are excellent in thermal conductivity and low friction in addition to smoothness, and can smoothly transfer heat to the medium with smooth movement of the medium.

  If you want to improve other properties (conditions) such as lubricity, high releasability, and elasticity, depending on the media type and platen specifications, you can apply a fluorine-based resin coating such as polytetrafluoroethylene (PTFE). You should wear it. In order to form this fluorine-based resin coating on the pressure contact surface, for example, a primer such as PEEK (base material) is baked on the ceramic surface as described above, and then baked in the same manner. Or you may make it affix such a resin film with a suitable adhesive material. This film may be appropriately determined so as to have desired heating characteristics, and can be formed to a thickness of about 10 to 30 μm, for example.

  This resin film such as a fluororesin is suitable for preventing adhesion of foreign matters such as dust, oil, lipids, and adhesives.

  If you want to control multiple types of properties, including temperature retention and heat capacity, depending on the type of media and the platen specifications, you may provide a resin layer such as the aforementioned fluororesin and a metal layer. Good. For example, when a 100 μm thick PTFE and a 100 μm thick SUS18-8 thin film are laminated and pasted on the ceramic surface, the thermal conductivity becomes 0.25 W / (m · K), which is about 1/100 that of ceramics. Although reduced, a heating head with improved wear resistance and improved elasticity and temperature retention can be obtained.

  If you want to heat the medium in a non-contact manner, or if you want to preheat the medium in a non-contact manner, it will be a sound or light that conducts heat through the space rather than heat it by pressure. It is preferable to form the coating layer 8 using a material having good emissivity and emissivity, or in particular, a material that easily emits infrared rays. As such a material, for example, a metal oxide such as aluminum or ruthenium oxide treated with black alumite is formed as a coating layer 8 on the surface facing the medium.

  The head substrate 1 used as a heating head varies depending on the size of the medium to be heated. For example, the head substrate 1 is made of a substantially rectangular plate having a length of about 40 to 350 mm, a width of about 5 to 25 mm, and a thickness of about 0.635 to 1.0 mm. As the material, it has a heat conductivity as good as possible, that is, has a heat conductivity of about 1 (for example, soda glass) to 200 W / (m · K), and has heat resistance in the heat generation temperature condition during use. In addition, the surface on which the heating resistor 2 is provided may have insulating properties, for example, ceramics such as alumina, aluminum nitride, or the like. An insulating film may be formed on the surface of a metal plate such as stainless steel to a thickness of about 5 to 20 μm, for example, by printing and baking a thick film paste for insulation.

  In the present invention, the other surface 1a of the head substrate 1 (the surface opposite to the surface on which the heating resistor 2 is provided) is used as a pressure contact surface or a heating surface, and the coating layer 8 is interposed on the surface facing the medium. Even if an alumina substrate having a rough surface is used as the head substrate 1, the medium 31 (see FIG. 3) to be heated is conveyed while being in contact with the coating layer 8 or in a non-contact manner without being directly pressed against the alumina. . This medium 31 is generally a PET (polyethylene terephthalate) or a paper surface coated with wax, but in the future, the emergence of composite media with different characteristics depending on various types of media and regions. In addition to contact heating and non-contact heating, it is expected that platens with various structures and materials will be used in the heating device, and a heating head that meets such various specifications is desired. It has become like this. The hardness of alumina is Vickers hardness Hv: about 1000.

  In order to meet such a demand, as described above, the coating layer 8 is formed on various processed surfaces according to the type of the medium 31, the heating method of the medium 31, and the like. In addition, as described above, the covering layer 8 is formed on the surface that is not provided with the heating resistor and is in pressure contact with the medium. Therefore, for example, before forming the heating resistor on one surface of the head substrate 1, it is preferable to form a surface processing layer on the back surface or side surface in advance. Alternatively, as described above, when the sub-substrate 11 as shown in FIG. 2 is provided and one surface of the sub-substrate 11 is a pressure contact surface, a coating layer is previously formed on one surface of the sub-substrate 11. 8 can be formed. By adopting such a configuration, the main body of the heating head 10 is manufactured together, and the sub-board 11 is processed and formed in various ways, so that the sub-board 11 can be placed on the surface of the heating resistor according to the purpose. By sticking on the heating head, a heating head according to the purpose can be produced efficiently and easily.

The heating resistor 2 is provided in a strip shape extending in the longitudinal direction so as to cover a part of the pair of electrodes 3 (see FIG. 3). In the example shown in FIG. 1, four heating resistors 2 having the same length (same characteristics) are formed in parallel. However, the size of the heating head varies depending on the medium to be heated. The heating resistor 2 can be formed. In addition to the above, a heating resistor for measuring the substrate temperature can be provided, or one of the heating resistors 2 for heating described above can be used for measuring the substrate temperature, and heat can be generated at an arbitrary number. The length of the portion to be heated can be varied to vary the heating length (medium width). The heating resistor 2 is formed, for example, by applying and baking a paste such as Ag + Pd + glass or silver and glass. It is also possible to use a further added and RuO ₂ thereto. When composed of an Ag—Pd alloy formed by firing, a sheet resistance of 100 mΩ / Sq to 500 mΩ / Sq is obtained (depending on the blending, amount of solid insulating powder, printing thickness, firing conditions, etc.), the ratio of the two Thus, the resistance value and the temperature coefficient can be changed. For example, the sheet resistance is about 200 mΩ, the width is 5 mm, the length is 100 mm, the thickness is about 10 μm (total resistance is about 3.6Ω), and the resistance temperature coefficient is about 1500 ppm / ° C. (when the temperature changes by 100 ° C. The resistance value changes by 15%). The heating resistor 2 is printed and formed so as to overlap a pair of electrodes 3 provided at both ends of the head substrate 1 in the longitudinal direction.

  The sheet resistance of the heating resistor 2 is set according to the size of the medium to be heated, the processing speed of the medium (speed of erasing recording, that is, the speed of passing over the heating head), and the like. For example, when the head substrate 1 has a width × length × thickness of 7 mm × 104 mm × 0.8 mm in the above example and is made of alumina, the amount of heat required to raise the head substrate 1 by 1 ° C. is 1 In order to increase 150 ° C. at .76 J, 150 × 1.76 = 264 J is required. For example, if the resistance between both ends of the heating resistor 2 is 3.6Ω, a heat amount of 160 W is generated by applying a voltage of 24 V, so 264 J / 160 W = 1.65 seconds. The required amount of heat can be supplied. That is, it is necessary to wait about 1.65 seconds for the substrate temperature to rise to a predetermined temperature of about 170 ° C. at the time of start-up. Thereafter, even if the medium is passed at a high speed, the heat capacity of the head substrate 1 is the same as the conventional one. Since it is an order of magnitude larger than only the thin heating resistor 2, the medium can be heated continuously with almost no temperature unevenness.

  For example, one or more heating resistors 2 are formed in parallel on substantially the entire surface of the head substrate 1 excluding a width of about 2 mm from the end of the head substrate 1. In the example shown in FIG. 1, four pieces having a width of about 3 mm are formed in parallel. In addition, a resistor for measuring the temperature of the head substrate can be provided in parallel with the heating resistor 2, and the temperature can be measured using the heating resistor 2. As shown in FIG. 1, the heating resistor 2 is formed over almost the entire length in the longitudinal direction of the head substrate 1, but one of the pair of electrodes 3 is formed in common with the plurality of heating resistors 2. It is also possible to form an electrode in the middle part. In particular, in the case of a heating resistor for temperature measurement, it is not necessary to provide it over the entire length of the head substrate 1, it can be provided only in the center portion, etc., or it is formed long in the longitudinal direction of the head substrate 1, A plurality of electrodes can be formed in the middle, and the partial temperature of the head substrate 1 can be measured. Such an intermediate electrode can be connected by bonding, crimping, high-temperature soldering or the like to an electric wire or a flexible cable.

  The heat generation characteristic of the heat generating resistor 2 is not limited to the above-described example and can be freely designed. However, as the temperature measuring resistor or the heat generating resistor 2 for measuring temperature, a resistor having a large resistance temperature coefficient is used. It is preferable to use a material, and it is particularly preferable to use a material of 1000 to 3500 ppm / ° C. to detect and control the temperature using a heating resistor 2 described later, or to prevent overheating due to thermal runaway. preferable. However, in the present invention, the heating of the medium is not performed directly by the heating resistor 2, but the medium is heated from the back surface 1a or side surface 1b (see FIG. 3) side of the head substrate 1 through the surface processing layer 8. The problem of thermal runaway is unlikely to occur and even a resistance material having a negative temperature coefficient can be used. If the material has a large temperature coefficient, it is easy to accurately measure the temperature of the head substrate 1 and control the temperature.

  In order to measure the temperature of the head substrate 1 using the heating resistor 2 or the temperature measurement resistor (since it is not intended for heating, a thin resistor film whose resistance value varies greatly depending on the temperature may be formed) For example, as shown in FIG. 4, a heating resistor 22 and a reference resistor 23 are connected in series to both ends of a DC power source 21 and the voltage V across the reference resistor 23 is measured. The temperature can be detected from the amount of change in the voltage and the temperature coefficient (determined by the material) of the heating resistor 22 that is known in advance. By controlling the voltage applied to both ends of the heating resistor 22 by the control means 25 according to the detected temperature, the temperature of the head substrate 1 can be maintained at a predetermined temperature. The temperature control of the heating resistor 22 by the control means 25 can be adjusted by applying a DC voltage and changing the applied voltage, or by driving the duty and changing the duty. The reference resistor 23 preferably has a small temperature coefficient. Further, the temperature measuring resistor or the heating resistor 22 used for temperature measurement is preferably as large as possible in absolute value (%) of the temperature coefficient (which may be positive or negative). Further, when used only for temperature measurement, for example, it is about 0.3 to 0.5 mm wide, and is attached to an appropriate position of the head substrate 1 (a portion in the vicinity of the portion where the medium is pressed and which does not interfere with the pressure contact). Preferably, the applied voltage of the resistor 22 for measuring the substrate temperature itself is kept low so as not to generate heat. Thereby, the temperature of the part which press-contacts the medium of the head substrate 1 can be estimated.

  The pair of electrodes 3 are, for example, a silver / palladium alloy or Ag that has a palladium ratio smaller than that of the material of the heating resistor 2 so as to be connected to the heating resistor 2 at both ends facing the longitudinal direction of the head substrate 1. It is formed by printing in the same manner as the heating resistor 2 with a good conductor such as a -Pt alloy. The pair of electrodes 3 is connected to the wiring of the wiring board 5 to be described later. However, in the present invention, the side on which the pair of electrodes 3 is provided faces the base 4 side, as will be described later. It is not necessary to provide connection wiring from the electrode 3 to the back side of the head substrate 1. Since the pair of electrodes 3 are not necessarily directly contacted with the surface on which the heating resistor 2 is provided, the unevenness of the surface is not a problem. It can also be formed, or as described above, it can be configured to be connected by direct bonding, pressure bonding, high-temperature soldering, or the like. Although not provided in the example shown in FIG. 1, when a substrate temperature measurement heating element is provided, the pair of electrodes can be formed in exactly the same manner.

  The base 4 is, for example, a metal plate such as an aluminum plate (thermal conductivity: 221 W / (m · K)), an iron plate (thermal conductivity: 83 W / (m · K)), or a ceramic such as aluminum nitride or aluminum oxide. And can be used to hold the head substrate 1. The base 4 is formed in a size corresponding to the head substrate 1 described above, and has a thickness of about 7 mm, for example.

  As described above, the wiring substrate 5 is connected to the pair of electrodes 3 so as to apply a voltage to the pair of electrodes 3 on the head substrate 1 and connected to a power source, and the temperature of the head substrate 1 described above. For example, it is formed of a printed circuit board or the like, but can also be formed of a flexible film as in an example described later. The wiring board 5 is also connected to a thermistor (not shown) separately provided on the head board 1 and may be managed as a double safety for preventing overheating of the head board 1. Furthermore, a temperature fuse or the like may be provided to cut off the voltage application to the pair of electrodes 3 when the temperature of the head substrate 1 rises too much.

  An adhesive 7 is attached to the wiring substrate 5 through the heat insulating plate 6 with the above-described head substrate 1 facing down on the one surface side of the base 4 (the one surface (front surface) on which the heating resistor 2 is provided is the base 4 side). It is attached by. The heat insulating plate 6, the wiring board 5, and the base 4 are also fixed by a heat-resistant adhesive (not shown) 7 (for example, silicone resin or epoxy resin), but these are fixed by screws or the like as will be described later. You can also. As this heat insulating plate 6, for example, the same material as the head substrate 1 and the same thickness can be used. However, for example, by forming a dam (bank) around and injecting the above heat-resistant adhesive with a dispenser or the like and curing it, the head substrate 1 can be easily fixed to the base 4 together with the formation of the heat insulating plate 6. it can. That is, the thermal conductivity of this silicone resin is about 0.15 W / (m · K), the thermal conductivity of alumina is 20 W / (m · K), and the thermal resistance of this heat-resistant adhesive is Since it is about 130 times, there is almost no heat escape. As a result, the temperature of the other surface 1a of the head substrate 1 (the upper surface in FIG. 1 and the contact surface with the spacer 8) also rises due to heat generated by energization of the heating resistor 2, and the spacer 8 is interposed on this surface. By pressing the medium with a rubber roll or the like, heating for writing or erasing the recording can be sufficiently performed.

  5A to 5D show modifications of the head substrate 1 and the coating layer 8 of the present invention. In any of the modifications, the covering layer 8 is provided on the upper surface of the head substrate 1, and the heating resistor layer 2 is provided on the lower surface of the head substrate 1 in the figure, although not shown. FIG. 5A shows an example in which the covering layer 8 is not provided over the entire width of the head substrate, that is, in FIG. 5A, a medium (not shown) is inserted from the right side of the figure. This is an example in which the head substrate 1 in the direction is not provided over the entire length, is formed short, and the edge of one surface of the head substrate 1 on the medium insertion side is C-plane processed. The end surface of the coating layer 8 is also rounded. FIG. 5B shows an example in which the coating layer 8 has the same structure as that shown in FIG. 5A, and the edge of one surface on the other insertion side of the head substrate 1 is rounded. In FIG. 5C, the length of the covering layer 8 is formed longer than the length of the head substrate in the traveling direction of the medium (the width of the head substrate 1), and the remaining portion of the end portion of the head substrate 1 is formed. In this example, it extends from the upper surface to the side surface, that is, is bent toward the head substrate 1 side and bonded to the side surface. In FIG. 5D, the covering layer 8 is formed long like FIG. 5C, and its end is bent toward the head substrate 1 side, but is not bonded to the side surface of the head substrate 1. It is an example. In any of these modifications, the medium 31 can be smoothly introduced to the pressure contact surface of the heating head.

  FIG. 6 is an explanatory cross-sectional view of another modification of the heating head 10 of the present invention. In other words, in this modification, the coating layer 8 is provided on the surface opposite to the surface on which the heating resistor 2 of the head substrate 1 is provided so as to protrude downward from both side surfaces of the head substrate 1. The surface on which the heating resistor 2 is provided is bonded to another ceramic substrate (protective substrate) 12 via an adhesive 13. The heating head 10 thus configured is fixed by being fitted into the concave portion at the top of the resin case 14 (mounting base) so that the coating layer 8 protrudes. In addition, an electrical cord (electric wire) is connected to a pair of electrodes (not shown) provided to be connected to both ends of the heating resistor 2, and is drawn from the side surface or the end surface of the resin case 14. That is, in this example, both end portions of the covering layer 8 protrude from both sides of the head substrate 1 in the width direction, and the protruding portions are bent toward the head substrate 1 side.

  FIG. 7 shows another modified example of the heating head 10 of the present invention, and shows an explanatory view of the top surface of the head substrate 1 provided with the coating layer 8 as viewed from above. That is, in the drawing shown in FIG. 7, the horizontal direction of the drawing is the longitudinal direction of the head substrate 1, and the vertical direction of the drawing is the width direction of the head substrate 1, in other words, the traveling direction of the medium. Therefore, the covering 8 is divided into three regions in a direction perpendicular to the traveling direction of the medium, a metal covering layer 8a is provided at both ends, and a resin covering 8b is provided at the center. As described above, by providing a plurality of different types of coating layers 8a and 8b in the longitudinal direction of the head substrate 1, heating can be performed with different heating conditions at the center and the end of the medium. , The degree of freedom can be improved.

DESCRIPTION OF SYMBOLS 1 Head board | substrate 2 Heating resistor 3 Electrode 4 Base 5 Wiring board 6 Heat insulation board 8 Coating layer 10 Heating head 31 Medium 32 Platen

Claims (10)

A plate-like head substrate, at least one belt-like heating resistor provided on one surface of the head substrate, and a pair of electrodes provided so that a voltage can be applied to the heating resistor. One surface where the heating resistor is not provided is a pressure contact surface with the medium, and a coating layer is deposited on the one surface, and the coating layer is longer than the length of the one surface of the head substrate in the moving direction of the medium. A heating head formed and formed by bending the end portion of the covering layer toward the head substrate at the end portion of the one surface . A plate-like head substrate, at least one belt-like heating resistor provided on one surface of the head substrate, a pair of electrodes provided so that a voltage can be applied to the heating resistor, and provided on the heating resistor A heating head comprising: a sub-substrate, wherein one surface of the sub-substrate different from the surface facing the heating resistor is a pressure-contact surface with the medium, and a coating layer is attached to the one surface. A plate-like head substrate, at least one belt-like heating resistor provided on one surface of the head substrate, and a pair of electrodes provided so that a voltage can be applied to the heating resistor. One surface on which the heating resistor is not provided is a pressure contact surface with the medium, and a coating layer is deposited on the one surface, and the coating layer has a length in a direction perpendicular to the penetration direction of the medium in two or more regions. divided we are in pressurized thermal head ing formed of different materials. A plate-like head substrate, at least one belt-like heating resistor provided on one surface of the head substrate, and a pair of electrodes provided so that a voltage can be applied to the heating resistor. One surface where the heating resistor is not provided is a pressure contact surface with the medium, a coating layer is deposited on the one surface, and the coating layer is formed of a plurality of layers including a fluorine-based resin coating and a metal sheet. pressurized thermal head that. The heating head according to any one of claims 1 to 4, wherein a surface treatment is applied to the one surface of the head substrate or the sub-substrate below the coating layer. The covering layer is formed to be longer than the length of the one surface of the head substrate or the sub substrate in the moving direction of the medium, and the end of the covering layer at the end of the one surface is on the side of the head substrate or the sub substrate. The heating head according to any one of claims 2 to 5 , wherein the heating head is bent. The covering layer is formed shorter than a length of the one surface of the head substrate or the sub-substrate in the moving direction of the medium, and an end portion of the covering layer on the medium intrusion side is formed on an R surface or a C surface. The heating head according to any one of claims 1 to 6 . 5. The heating head according to claim 1 , wherein the coating layer is formed of different materials by being divided into two or more regions with a length in a direction perpendicular to the penetration direction of the medium. The coating layer is heated head according to any one of claims 1 to 8 which is a coating layer of the glass powder. The heating head according to any one of claims 1 to 3 and 5 to 9 , wherein the coating layer is formed of a plurality of layers including a fluorine resin coating and a metal sheet.

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