JP5587059B2 - Gloss processing equipment - Google Patents

Description

  The present invention relates to a gloss processing apparatus.

  Conventionally, many printed materials have different gloss depending on the printing rate due to the difference in gloss between the recording material and the color material. In order to make the overall gloss uniform for such a printed matter, various methods for creating a uniform glossy surface by various post-treatment processes such as overcoat have been proposed and implemented. Furthermore, in recent years, various techniques for controlling the gloss have been proposed and implemented. For example, in offset printing, after printing with color material ink, a method that uses UV curable transparent ink, offset printing to a specific part, and fixing by UV irradiation of the whole is used, and various gloss It enables expression. As a result, it is possible to improve the gloss of a specific portion (photograph, headline portion, etc.) and output a printed matter with a rich visual effect. In electrophotographic recording, the present applicant has proposed a technique for improving the gloss of the entire printed material and recording a photographic tone, as in Patent Document 1, for example. Further, a technique for improving gloss and giving a gloss like a photograph by changing the surface property of the printing surface of an image using transparent toner as in Patent Document 2 has been proposed.

JP 2007-086747 A JP-A-6-273994

However, with the conventional gloss processing technique, it has been difficult to partially perform photographic tone gloss processing on different areas for each sheet. The term “photographic tone” as used herein means a high glossiness of 40% or more, further 80% or more in 60 degree gloss. Various means for imparting high gloss to the entire recorded image have been proposed as in the background art example, but a method that can be partially processed has not yet been found. Here, the partial gloss processing means that gloss processing is performed not only on an image forming area where a photographic image is formed, but also on a heading character or an arbitrary shape or area according to the print content. Is meant to do.
In Patent Document 1, since the glossiness of an image after gloss processing depends on the surface property of the fixing belt used for the gloss processing, it is not easy to adjust the gloss level in stages. When the gloss is to be adjusted step by step, various belts having a surface property capable of realizing the desired gloss are required. (In addition, the glossy processing medium needs to ensure adhesion with the belt, and it was not possible to change the glossiness to a desired level by applying post-processing to any medium.)
In Patent Document 2, the gloss range after gloss processing is dependent on the physical properties specific to the constituent components of the transparent toner used for image formation, for example, the melting point of the resin, so that the gloss control range is narrow and desired. Glossiness may not be obtained. In order to obtain a desired gloss level, various kinds of toners having characteristics capable of realizing the desired gloss level are required. As the number of toner types to be used increases, when it becomes necessary to add a developing device or the like, the image forming apparatus is also increased in size. Furthermore, since the range of glossiness after gloss processing is narrow, it is not possible to record an arbitrary gloss portion in the same plane.

  An object of the present invention is to provide a gloss processing apparatus capable of easily performing selective and stepwise gloss processing of an arbitrary region.

In order to achieve the above object, the gloss processing apparatus of the present invention comprises:
A heater,
A transfer film slidable on the heater;
A pressure member provided on the side opposite to the heater with respect to the transfer film;
With
At the nip portion between the transfer film and the pressure member, the sheet on which the image is formed is moved relative to the heater together with the transfer film and is carried on the image forming surface side of the sheet. In the gloss processing apparatus that applies gloss processing by transferring the surface shape of the transfer film by heating and pressing the thermoplastic resin material,
The heater has a substrate and a plurality of heating elements that are arranged on the substrate and generate heat by energization, and is configured to be able to individually control energization / non-energization of the plurality of heating elements,
The energization / non-energization of the plurality of heating elements is controlled based on a density pattern obtained by binarizing gloss density information in the gloss processing region.

  According to the present invention, it is possible to easily perform selective and stepwise gloss processing of an arbitrary region.

Sectional drawing which shows schematic structure of the gloss processing apparatus of embodiment. The figure which shows schematic structure of the drive circuit of a thermal head Schematic explaining the structure of the heating element of the thermal head Block diagram showing gloss processing circuit Flow chart showing the flow of binarization processing The figure which shows an example of a binarization process (density pattern method) A graph showing the relationship between the number of screen lines and gloss (20 °)

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

[Entire device configuration]
FIG. 1 is a cross-sectional view showing a schematic configuration of the gloss processing apparatus of the present embodiment. The gloss processing apparatus of the present embodiment transfers the surface shape of the transfer film by softening the thermoplastic resin (on the sheet) carried on the sheet by heating and deforming it using the surface shape of the transfer film. Gloss processing is performed. First, the overall configuration of the gloss processing apparatus will be described.
In FIG. 1, reference numeral 1 denotes an apparatus main body, 2 a cassette on which sheets (recording materials) P are stacked, and 3 a feeding roller for separating and feeding the sheets P from the cassette 2 one by one. Reference numeral 4 denotes a pair of sheet feed rollers that sandwich the sheet P fed from the feed roller 3 and convey the sheet P toward the processing unit (heating unit, nip unit). The sheet feed roller pair 4 is configured to reciprocate the sheet P. A sensor 14 detects the leading edge of the sheet P when the sheet P is conveyed in advance to the recording start position of P1.
Reference numeral 5 denotes a platen roller as a pressure member disposed across the sheet conveyance path, and 6 denotes a thermal head as a heater that selectively generates heat in accordance with recording information (surface treatment information). The platen roller 5 and the thermal head 6 are arranged facing each other.
Reference numeral 8 denotes a transfer film (hereinafter referred to as a film) that is pressed against the sheet P by the thermal head 6 and is selectively heated. Reference numeral 7 denotes a film cassette (storage portion, mounting portion) in which the film 8 is stored. Reference numerals 12 and 13 denote a film take-up shaft and a film supply shaft for the film 8 provided in the film cassette 7, respectively. Reference numeral 11 denotes a separating member that separates the film 8 and the sheet P that are heated and pressed by the thermal head 6. Reference numeral 9 denotes a discharge roller pair for discharging the sheet P out of the apparatus main body, and reference numeral 15 denotes a discharge tray.

(Thermal head)
The basic configuration and basic specifications of the thermal head 6 will be described below. FIG. 3 is a schematic diagram for explaining the configuration of the heating element of the thermal head 6. In the thermal head 6, a common electrode 23a and a lead (individual) electrode 23b are formed on a glaze (hereinafter referred to as a heat insulating layer) 22 printed on a substrate 21 using alumina or the like via a heating element 25. It is constituted by. (The heating element 25 is formed on the lower surface of each electrode.) Further, a protective film (overcoat layer) 24 is formed on the upper surface of the substrate 21, the heat retaining layer 22, the electrodes 23 a and 23 b, and the heating element 25. ing. The thermal head 6 includes a driving circuit for selectively applying electric power to the heating element 25 to generate heat, and a component such as a heat radiating plate for radiating excess heat after the sheet P is heated. It is configured. Here, the gloss processing apparatus of the present embodiment is provided with control means for controlling the amount of heat generated by the heating element 25 using this drive circuit.
In this embodiment, the thermal head 6 having a heating element density of 300 dpi (dots per inch), a recording density of 300 dpi, a driving voltage of 30 V, and a heating element average resistance value of 5000Ω is used. However, the head configuration and specifications of the thermal head 6 are not limited to this.

FIG. 2 is a diagram showing a schematic configuration of a drive circuit of the thermal head 6.
A plurality of heating elements 25 are arranged on the substrate 21 so as to form one line, and electrodes are wired on both sides thereof. A driver IC including a register group for transferring and holding data for one line is provided on the same substrate or on a separate wiring substrate.
The thermal head 6 configured as described above can independently adjust the heat generation amount of the plurality of heating elements 25 (the heating element can be individually energized and de-energized), and the heating area for the sheet P can be controlled. It is configured to be controllable. Thus, an intermediate gloss process can be performed on the surface of the sheet P, and a gloss process can be partially performed on the surface of the sheet P. Here, the thermal head 6 is configured to be able to heat a part of the region where the film 8 passes through the nip portion N together with the sheet P, so that a part of the region on the sheet P can be heated. Gloss processing is possible.

(Platen roller)
The platen roller 5 is formed by forming a member having a high coefficient of friction such as hard rubber in the form of a roller. For example, the platen roller 5 is made of a rubber roller using silicon rubber or the like, and is rotatably attached to the apparatus main body 1 by a shaft 5a. The platen roller 5 is configured to transport the film 8 by being driven by a drive source (not shown). The platen roller 5 is provided on the opposite side of the thermal head 6 with respect to the film 8.

(the film)
The film 8 is slidably provided on the thermal head 6 and has a surface shape for performing a gloss treatment on the sheet P having a thermoplastic resin material on the surface (image forming surface side). . Further, the film 8 is wound and stored on the film supply shaft 13 by a desired length, and is supplied to a processing unit including the thermal head 6 by being wound by the film winding shaft 12 as necessary. In the case where the film 8 has a replaceable specification in the gloss processing apparatus, the film 8 is detachably attached to the gloss processing apparatus main body.
The film 8 is made of a thin flexible material in order to locally heat the sheet surface. From this viewpoint, the thickness of the film 8 is desirably 40 μm or less. In addition, the material needs to have heat resistance to the thermal head 6. PI (Polyimide) I
A material having heat resistance exceeding 200 degrees is preferable. Although a heating history remains, a general resin film such as PET (polyethylene terephthalate) can also be used.

(Separation member)
A typical configuration of the separating member 11 will be described.
The separating member 11 has two roles of a film cooling function and a film separating function by curvature. The separation member 11 is made of a metal such as SUS (stainless steel), and the separation curvature is set to a sufficiently small value (in this example, the curvature radius is 1 mm). It is configured so that it can be released more reliably.

(Sheet (cut paper))
In the present embodiment, a recording material (printed material) output by an electrophotographic recording apparatus is used as a sheet (material to be processed). As the recording material, art paper for printing (basis weight 157 g / m ² ) was used. In this embodiment, two types of recording materials are used: a recording image using CMYK four-color toner (thermoplastic resin) and a recording material image-formed by a five-color process including a thermoplastic resin-based transparent toner that does not include a coloring material. It was. For the transparent toner, after separation into CMYK, the transparent toner was supplemented to the portion with a low printing rate, and a printing pattern was determined and output so as to cover the entire recording material with the toner. As a result, it is possible to perform a gloss process on an arbitrary place of the recording material. Further, the toner fixing state in the electrophotographic recording apparatus was adjusted so that the gloss of the recording material by electrophotographic recording was about 10% at 60 ° gloss.

Further, in the present embodiment, the sheet is not limited to the above four-color and five-color processes, and gloss processing is similarly performed when an image is formed by a four-color process on a sheet coated with a thermoplastic resin. It becomes possible. The same applies to sheets recorded by melt thermal transfer recording, sublimation thermal transfer recording, ink jet recording, and the like. Even in this case, by covering the sheet surface with a thermoplastic material such as a thermoplastic resin or WAX, it is possible to perform a gloss treatment at an arbitrary position on the entire sheet surface. Further, gloss processing can be similarly performed on a recorded image by melt thermal transfer recording (an image in which image information is recorded by a WAX layer (thermoplastic material) containing a color material on a sheet).
As described above, in the sheet carrying the thermoplastic material of the present embodiment, when the material for forming an image on the sheet is a thermoplastic material, and when the thermoplastic material is coated on the image forming surface Is included.

[Description of operation]
In the apparatus main body 1 shown in FIG. 1, when the sheet P on which an image is recorded is separated and fed one by one from the cassette 2 by the feeding roller 3, the sheet P is directed to the processing unit by the sheet feeding roller pair 4. It is nipped and conveyed. When the sheet P is conveyed in advance to the processing start position of P1, the length of the sheet P is measured by counting the time that passes through the sensor 14 that detects the leading edge of the sheet P.
In the processing unit, the platen roller 5 and the thermal head 6 are arranged to face each other with the sheet conveyance path interposed therebetween (via the film 8), so that a nip portion N is formed between the film 8 and the platen roller 5. Has been. In a state where the film 8 is positioned on the sheet P (a state where the sheet P and the film 8 are overlapped), the sheet P and the film 8 move while being heated and pressurized in the nip portion N. Here, when the film 8 is positioned on the sheet P, the image forming surface of the sheet P is in contact with the film 8.
Further, while the film 8 and the sheet P moving together with the film 8 are pressed at the nip portion N, each heating element of the thermal head 6 is heated based on the gloss information for the gloss processing. Thereafter, the film 8 and the sheet P are separated by the separating member 11, whereby a desired gloss treatment is performed on the sheet P.

The platen roller 5 is rotatably attached to the apparatus main body 1 by a shaft 5a. As the feed roller 3 rotates, the film take-up shaft 12 and the film supply shaft 13 disposed in the film cassette 7 are driven to rotate, so that the film 8 has a length corresponding to the length of the sheet P and the length of the gloss processing area. Be transported.
The thermal head 6 heats the film 8 in accordance with the gloss information, and applies a gloss process to the sheet P that is nipped and conveyed together with the film 8. The thermal head 6 is configured to press the platen roller 5 through the film 8. Has been. Specifically, the platen roller 5 is rotatably attached to the apparatus main body 1 by a shaft 5a, and presses against the thermal head 6 when the sensor 14 detects that the sheet P has been conveyed to the gloss processing start position. It is configured as follows.

Therefore, when the platen roller 5 is rotated with the film 8 inserted between the platen roller 5 and the thermal head 6, the film supply shaft 13 and the film take-up shaft 12 having no drive source are driven, and the film 8 is desired. It is conveyed by the length of. The film 8 is wound up by the length of the sheet P, and after completion of the glossing process, the platen roller 5 is separated from the thermal head 6.
The sheet P nipped and conveyed by the nip portion N is guided to the discharge roller pair 9 and is discharged out of the casing, and the gloss processing is completed. As the sheet P, roll paper can also be used.

In the present embodiment, the sheet feeding roller pair 4 allows the gloss processing to be performed a plurality of times while reciprocating the sheet P. However, the present invention is not limited to such a configuration. For example, it is possible to use a platen drum and perform the glossing process while rotating the drum a plurality of times. Further, the platen roller can be directly driven to perform the gloss processing only once in one direction.
Further, the thermal head 6 may be configured to be movable, and the gloss processing may be performed by moving the thermal head 6 within a predetermined range of the nip portion N.
In other words, any glossy process may be performed as long as the sheet P and the film 8 in a superimposed state (contact state) move relative to the thermal head 6.
In addition, the movement (conveyance) speed of the sheet P during the gloss processing of this embodiment is controlled to 50 mm / s.

[Processing method for thermal head heating pattern]
A heating pattern processing method for controlling the heating element of the thermal head 6 that is most important in the gloss processing of this embodiment will be described.
As a method of binarization processing in a circuit that controls heating of the heating element of the thermal head, output data is assigned to a matrix of a plurality of recording pixels m × n (m and n are integers) for one pixel of input data. A constituent density pattern method is used. The simplest density pattern method expresses 5 levels of density using a 2 × 2 array. That is, gradation is expressed by changing the density of black pixels per unit area. That is, the density pattern is a heating pattern, and the heating element in the portion corresponding to the black pixel is energized and becomes a portion where the gloss process is performed. Therefore, the density of the heating element to be energized is controlled to express the glossy gradation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 4 is a block diagram showing a gloss processing circuit for carrying out the present invention. In this figure, reference numeral 31 denotes a processed image input circuit for inputting image data (number of pixels horizontal X1, vertical Y1) as glossy shade information in the gloss processing region. A density pattern processing circuit 32 performs binarization processing according to the density pattern method, and outputs image data (number of pixels horizontal X0, vertical Y0). Reference numeral 33 denotes a thermal head control unit built in the gloss processing apparatus (not shown).
FIG. 5 is a flowchart showing a processing procedure of the gloss processing apparatus shown in FIG.
After the process is started in step S1 in FIG. 5, image data and pixel number information are input in step S2. Here, the number of pixels in the horizontal direction of the input image data is X1, and the number of pixels in the vertical direction is Y1. This image data is output via the control unit of the thermal head. At this time, the number of output pixels in the horizontal direction is X0, and the number of output pixels in the vertical direction is Y0.
In this case, the values of mX and mY are sent to step S3, and matrix selection processing is performed. This matrix selection processing is executed in the processing image input circuit (FIG. 4), and is used for the density pattern method, which is a matrix pattern TX × TY (TX = 1, 2, 3,...: TY = 1. , 2, 3,... Are prepared in advance in a matrix table (not shown). In this example, a matrix pattern as shown in FIG. 6 is selected so that the recording pixel corresponds to 4 × 4 for one input pixel, and the density pattern method is followed in the binarization processing in step S5. Binarization processing is performed.
In this example, an example of enlarging to 4 times is shown. However, if mX = mY = 5, a matrix pattern of 5 × 5 so that a recording pixel corresponds to 5 × 5 with respect to one input pixel. Is selected in step S3, and binarization processing is performed by the matrix pattern. The binarized image data is sent to the thermal head (step S6).
In addition, it is possible to cope with a magnification different from h times in the vertical direction and w times in the horizontal direction by selecting h × w of the matrix pattern.

[Examples and Comparative Examples]
Hereinafter, examples and comparative examples using the best mode will be described and described in detail.
(Comparative Example 1) In this comparative example, paying attention to the screen line number of gloss processing, the screen line number is set to 30 lpi (lines per inch). In addition, a sheet material having PI and a thickness of 12 μm is used as the transfer film.
(Comparative Example 2) In this comparative example, the number of screen lines is set to 200 lpi with respect to Comparative Example 1. (Embodiment 1) In this embodiment, the number of screen lines is set to 50 lpi with respect to Comparative Example 1.
(Embodiment 2) In this embodiment, the screen line number is set to 100 lpi with respect to Comparative Example 1. (Embodiment 3) In this embodiment, the screen line number is set to 150 lpi with respect to Comparative Example 1. (Comparative Example 3) In this comparative example, paying attention to the transfer film, PI and a sheet material having a thickness of 1 μm are used as the transfer film. The number of screen lines is 50 lpi.
(Comparative Example 4) In contrast to Comparative Example 3, this comparative example uses PET as a transfer film and a sheet material having a thickness of 18 μm.
(Example 4) Compared with Comparative Example 3, this comparative example uses PET as a transfer film and a sheet material having a thickness of 2 µm.
(Example 5) In contrast to Comparative Example 3, this comparative example uses PET as a transfer film and a sheet material having a thickness of 4 μm.
(Example 6) Compared to Comparative Example 3, this comparative example uses PET as a transfer film and a sheet material having a thickness of 8 μm.

[Evaluation method]
(A) Linearity of gloss gradation Gloss evaluation was evaluated by 20 ° gloss using a trigloss meter (manufactured by BYK Gardner). The image used for the measurement is an image in which gloss data of about 1 inch square is recorded on the A4 size recording image in which black (single color) is output at a printing density of 100% by using the gloss processing of this embodiment. The input image data used for the gloss process is data in which the print density (%) is changed by 10 from 0 to 100. On the other hand, a total of six types of images were prepared, one type of image sample that was not subjected to the gloss processing of this embodiment and five types of image samples that were subjected to gloss processing with different screen lines. The number of screen lines of the glossy processed image sample is 30 lpi (Comparative Example 1), 50 lpi (Example 1), 100 lpi (Example 2), 150 lpi (Example 3), and 200 lpi (Comparative Example 2).
Among the above six types, the linearity of the gloss gradation is evaluated for a total of four types of images, that is, an image sample that is not subjected to the gloss processing of this embodiment and an image sample that is performed with screen line numbers of 50 lpi, 100 lpi, and 150 lpi. did. As shown in FIG. 7, a graph plotting the 20 ° gloss values of the present example (with screen processing, variable number of lines) and the conventional example (without screen processing) was created, and the linearity in halftone was evaluated. . In the created graph, the vertical axis represents gloss (20 °), and the horizontal axis represents image density (input image data) before screen processing.
(A) Ease of noticeability of gloss data screen The easiness of the gloss data screen was visually evaluated. The image used for the measurement is the same as the image for which (a) the linearity of the gloss gradation is evaluated. The following criteria were used for evaluation.
○: No defect (notch at low gradation or occurrence of blur at high gradation) is observed at any place.
X: A defect is recognized.
(C) Image clarity Image clarity is a measure of how clearly and when an object is reflected on the surface, the image is projected without distortion.
The evaluation of image clarity was performed by visual evaluation. Subjective evaluation was performed based on the sharpness of the light source transferred into a sample at a clear viewing distance of about 250 mm. The distance between the sample and the light source was adjusted to about 2 to 3 m, and the angle formed by the light source, the sample, and the viewpoint was adjusted to 20 to 40 degrees.
In the image sample patch of each example, the following evaluation was performed using the patch with the best image clarity as the evaluation criterion.
○: Same image clarity regardless of screen processing.
X: There exists a site | part by which the image clarity fall is recognized by screen processing clearly.
(D) Fine line reproducibility of gloss data The image used for the measurement was an image obtained by processing a print pattern with one line and one space (hereinafter referred to as 1l1s). Moreover, in the evaluation of this item, PET film as a transfer film, thickness 1 μm (Comparative Example 3), 2 μm (Example 4), 4 μm (Example 5), 8 μm (Example 6), 18 μm (Comparative Example 4) The sheet member was used. A material having heat resistance exceeding 200 degrees, such as polyimide, is preferable, but a general resin film such as PET can be used although a heating history remains. Note that the number of screen lines was 50 lpi.
About the obtained image data, the thin line reproducibility of the gloss data was visually evaluated. The following criteria were used for evaluation.
○: No defect (a part that cannot be recognized as a line) is recognized.
Δ: Some defects are recognized, but it is close to the standard.
X: A defect is recognized.

（ア）グロス階調の線形性
図７は、本実施形態（スクリーン処理あり、線数を可変）と従来形態（スクリーン処理なし）の２０°グロス値をプロットしたグラフである。なお、作成したグラフは、縦軸をグロス（２０°）、横軸をスクリーン処理前の画像濃度（入力画像データ）で示し、中間調での線形性を評価した。
図７において、本実施例の光沢処理を行った画像と、処理していない画像とを比較してみると明らかなように、従来形態においては中間調で得られなかった線形性を、本実施形態では得ることができた。さらに、本実施形態のサーマルヘッド解像度３００ｄｐｉ（１ラインあたりのドット数）の場合、光沢画像濃度（入力データ）中間調（画像濃度３０〜６０％）において、スクリーン線数ｓを低線数にしていくほど、線形性が徐々に高くなることが分かった。すなわち、スクリーン線数ｓを１５０ｌｐｉ（実施例３）、１００ｌｐｉ（実施例２）、５０ｌｐｉ（実施例１）と低線数にしていくと線形性が徐々に高くなる。これは、光沢濃度中間値での任意の段階的なグロス制御が可能になることを示している。
（イ）光沢データのスクリーンの目立ちやすさ
上記の通り、本実施形態のサーマルヘッド解像度３００ｄｐｉの場合、上記に示すように、スクリーン線数１５０ｌｐｉ（実施例３）、１００ｌｐｉ（実施例２）、５０ｌｐｉ（実施例１）と低線数にしていく、線形性が徐々に高くなることが分かった。しかし、さらに低線数の３０ｌｐｉ（比較例１）では低階調での欠けまたは高階調でのツブレが発生し、光沢データのスクリーンのパターンが目立つようになった。
（ウ）写像性
本実施形態のサーマルヘッド解像度３００ｄｐｉの場合、スクリーン線数を２００ｌｐｉ（比較例２）とした場合に、写像性の低下がみられた。
（エ）光沢データの細線再現性
ＰＥＴフィルム、厚さ２μｍ以上８μｍ以下では、ラインとして認識不可能な不良部分はみられず、細線の再現性があることを確認できた。しかし、フィルム厚さ１８μｍ（比較例４）では、細線の再現性に不良が見られた。これは、フィルムの厚さと熱伝導の関係によるものと考えられる。また、厚さ１μｍ（比較例３）では強度が足りなかったためと考えられるフィルムの破断が起きた。この結果から、フィルムの厚みは２μｍ以上８μｍ以下（実施例４、実施例５、実施例６）であることが好ましい。
以上の結果から、本実施形態において、［１］グロス階調に高い線形性をもたせるためには、スクリーニング処理をした光沢処理データに基づいた加熱部の制御が必要であることが分かる。［２］さらに、光沢データのスクリーンの目立ちやすさと写像性の観点から、本実施形態のサーマルヘッド解像度３００ｄｐｉの場合には、スクリーニング処理に用いるスクリーン線数は、５０〜１５０ｌｐｉまでの範囲が好ましい。ただし、スクリーン線数の好ましい範囲はサーマルヘッドの解像度により変わることが容易に予測される。このことから、サーマルヘッドの解像度を、主走査方向のドット数をｘ個、副走査方向（主走査と直交する方向）のドット数をｙ個と表したときには、スクリーニング処理の線数ｓ（ｌｐｉ）が５０≦ｓ≦（ｘ／２、ｙ／２）の関係を満たすことが好ましい。［３］また、任意の位置に段階的な光沢を付与する場合に重要となる細線再現性の観点からは、転写フィルムとして用いるシート部材の厚みは２〜８μｍにすることが望ましい。 [Each Example and Evaluation Result]
Table 1 shows the evaluation results in each example and comparative example of the present embodiment.

(A) Linearity of gloss gradation FIG. 7 is a graph plotting 20 ° gloss values of the present embodiment (with screen processing and variable number of lines) and the conventional embodiment (without screen processing). In the created graph, the vertical axis represents gloss (20 °), and the horizontal axis represents image density (input image data) before screen processing, and the linearity in halftones was evaluated.
In FIG. 7, as is apparent from a comparison between the image subjected to the gloss processing of the present embodiment and the image not processed, the linearity that cannot be obtained in the halftone in the conventional mode is shown in the present embodiment. In form could be obtained. Furthermore, in the case of the thermal head resolution of 300 dpi (number of dots per line) of the present embodiment, the screen line number s is set to a low line number in the glossy image density (input data) halftone (image density 30 to 60%). It was found that the linearity gradually increased as the time went on. That is, when the screen line number s is reduced to 150 lpi (Example 3), 100 lpi (Example 2), and 50 lpi (Example 1), the linearity gradually increases. This indicates that it is possible to perform an arbitrary stepwise gloss control at an intermediate gloss density value.
(A) Ease of conspicuousness of gloss data screen As described above, in the case of the thermal head resolution of 300 dpi according to the present embodiment, as shown above, the number of screen lines is 150 lpi (Example 3), 100 lpi (Example 2), 50 lpi. It was found that the linearity gradually increased as the number of lines was reduced to (Example 1). However, with a lower line number of 30 lpi (Comparative Example 1), chipping at low gradations or blurring at high gradations occurred, and the screen pattern of gloss data became conspicuous.
(C) Image clarity In the case of the thermal head resolution of 300 dpi of the present embodiment, the image clarity was reduced when the number of screen lines was 200 lpi (Comparative Example 2).
(D) Fine line reproducibility of gloss data In the PET film having a thickness of 2 μm or more and 8 μm or less, no defective portion that cannot be recognized as a line was observed, and it was confirmed that the thin line was reproducible. However, when the film thickness was 18 μm (Comparative Example 4), the fine line reproducibility was poor. This is considered to be due to the relationship between the thickness of the film and heat conduction. In addition, the film was considered to be broken at a thickness of 1 μm (Comparative Example 3), which was thought to be due to insufficient strength. From this result, the thickness of the film is preferably 2 μm or more and 8 μm or less (Example 4, Example 5, and Example 6).
From the above results, it can be seen that in this embodiment, in order to give [1] gloss gradation high linearity, it is necessary to control the heating unit based on the gloss processing data subjected to the screening process. [2] Further, from the viewpoint of the conspicuousness of the screen of gloss data and the image clarity, in the case of the thermal head resolution of 300 dpi of this embodiment, the number of screen lines used for the screening process is preferably in the range of 50 to 150 lpi. However, it is easily predicted that the preferable range of the number of screen lines varies depending on the resolution of the thermal head. Therefore, when the resolution of the thermal head is expressed as x in the number of dots in the main scanning direction and y as the number of dots in the sub-scanning direction (direction orthogonal to the main scanning), the number of screening processing lines s (lpi) ) Preferably satisfies the relationship of 50 ≦ s ≦ (x / 2, y / 2). [3] Further, from the viewpoint of fine line reproducibility, which is important when providing stepwise gloss to an arbitrary position, the thickness of the sheet member used as the transfer film is desirably 2 to 8 μm.

According to the present invention, glossy processing including high gloss of photographic tone can be applied to any part of a medium to be processed in any step depending on the heating pattern of the thermal head. Further, the surface treatment can be appropriately performed according to the gloss information applied to the medium to be processed. Furthermore, the fine line reproducibility by thermal diffusion becomes good, and a desired graded gloss can be processed at an arbitrary position. That is, it is possible to express not only a gradual gloss, but also a specific gloss gradation in which the glossiness gradually changes while maintaining image clarity.
The present invention introduces a new information concept called gloss information in addition to color image information, and brings about a great effect of greatly increasing the diversity of output products.

5 Platen roller; 6 Thermal head; 8 Film; 21 Substrate;
25 Heating element; N nip; P sheet

Claims (2)

A heater,
A transfer film slidable on the heater;
A pressure member provided on the side opposite to the heater with respect to the transfer film;
With
At the nip portion between the transfer film and the pressure member, the sheet on which the image is formed is moved relative to the heater together with the transfer film and is carried on the image forming surface side of the sheet. In the gloss processing apparatus that applies gloss processing by transferring the surface shape of the transfer film by heating and pressing the thermoplastic resin material,
The heater has a substrate and a plurality of heating elements that are disposed on the substrate and generate heat by energization, and is configured to be able to individually control energization / non-energization of the plurality of heating elements,
A gloss processing apparatus, wherein energization / non-energization of the plurality of heating elements is controlled based on a density pattern obtained by binarizing gloss density information in a gloss processing area. The gloss processing apparatus according to claim 1, wherein the transfer film has a thickness of 2 to 8 μm.

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