JPH0486284A - Image formation device - Google Patents

Abstract

PURPOSE:To enhance a transfer accuracy and thereby improve image quality by forming a transparent ink layer on the surface of an image formation medium, then transferring this transparent ink layer to the surface of a medium in which an image is formed and transferring a coloring ink layer to the top of the transparent ink layer. CONSTITUTION:The transparent ink layer 23b of an ink ribbon 23 is transferred to the entire surface of a sheet P wound around the periphery of a platen drum 22 by driving TPH 21. Then the application of pressure of TPH 21 is once cancelled and the specified amount of the ink ribbon 23 is taken up to head a coloring ink layer 23c. Next, the platen drum 22 is rotated in an arrow B direction and the coloring ink layer 23c is transferred to the surface of a transparent ink 51 which covers the surface of the sheet P using TPH 21 which is driven by an image electric signal. In this case, an activated coloring ink 52 becomes fused to the transparent ink 51 which is made of a low melting-point ink and the both inks are transferred to the surface of the sheet P in one piece.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object 1] (Industrial Application Field) The present invention relates to an image forming apparatus, and in particular, to a method for forming a copy image on an image forming medium (hereinafter referred to as paper) using a thermal transfer method. The present invention relates to an image forming apparatus that can perform image transfer.

(Prior Art) A thermal transfer type copying machine is known as one of the image forming apparatuses. This copying machine consists of a platen drum, which is a drum-shaped support, and a thermal head (TPH), which is a heating means.
The paper and the ink ribbon, which is an image forming medium, are held between them with a predetermined pressure 12, and electric power is supplied to a heating element provided in the TPH according to an image electric signal to generate heat according to this electric power. A colored ink layer applied to an ink ribbon is thermally melted and transferred to paper.

The image electrical signal is usually obtained by irradiating a document placed on a document table with light from a light source, scanning it 17, and converting the reflected light into an electrical signal by a solid-state imaging device (CCD).

(Problems to be Solved by the Invention) However, in the thermal transfer type copying machine configured as described above, the transfer probability of the ink layer transferred to the surface differs depending on the smoothness of the surface of the paper. When this smoothness is expressed as Bekk smoothness, when Bekk smoothness is less than 20 seconds, there is a problem that the transfer probability is low and the printing quality is deteriorated.

The present invention has been made in view of the above points, and is a thermal transfer method that can transfer colored ink with a high transfer probability even to paper with low slipperiness and can make high-quality copies. The purpose of the present invention is to provide an image forming apparatus.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the second object, the present invention provides an image forming medium and a surface between a drum-shaped support means and a heating means having a plurality of heating elements. and an image forming medium on which a colored ink layer is formed are held together under a predetermined pressure, power is supplied to the heating element to generate heat, and the colored ink layer is transferred onto the image forming medium to form an image. In the forming device,
A transparent ink layer is formed on the surface of the image forming medium, and after the transparent ink layer is transferred to the surface of the image forming medium, the colored ink layer is transferred to the upper surface thereof [, ing.

(Function) According to the above structure, even when the surface smoothness of the paper that is the image forming medium is low, the transparent ink layer of the inkliphone that is the image forming medium can improve the smoothness by (“I” @) on the surface of the paper. As a result, when the colored ink layer is transferred by heating and melting, it is possible to increase the transfer probability and improve the image quality.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

An embodiment of the present invention is shown in FIGS. 1 to 3.

FIG. 3 is a sectional view showing the overall structure of a thermal transfer type copying machine to which this embodiment is applied. The thermal transfer copying machine in the figure is
A copying machine main body 1 has a document table 2 made of transparent glass fixed on two sides, a document cover 3 whose one end is rotatably supported on the top surface of the main body 1 and covers the top surface of the document table 2, and one side of the main body 1. It consists of an iJ1 paper tray 4 and a paper feed cassette 5, which are removably loaded in the upper and lower parts of the paper tray and protrude from the negative side.

Also, inside the main body 1, there is a document scanning section 6 that scans and reads a document (not shown) set on a document table 2''2, and a photoelectric conversion section 7 that converts an optical image read by the document scanning section 6 into an electrical signal. , an image forming section 8 is provided which drives the TPH using this electric signal to form a copy image on the paper P.

The original scanning unit 6 uses light ri, 9 and a first light source such as a halogen lamp.
A first carriage 11 on which a mirror 10 of 1.3 is installed, a second carriage on which a second and third mirror 12, 1.3 is installed, a variable magnification lens block 15, a 4th. and a fifth mirror 1617. The beam of light from the light source 9 installed in the first carriage 11 is focused onto the original by the deflector 8, and the reflected light from the original is reflected by the first mirror 10. Mirror of 2] Guided by 2.

The light guided to the second mirror 12 is reflected by the third mirror]3, passes through the lens block 15, is reflected by the fourth and fifth mirrors 16.17, and is guided to the CCD 1.9. At this time, the moving speed of the second carriage 14 in the direction indicated by the arrow A-A is 1/2 of the moving speed of the first carriage 11 in the same direction, and the lens block 1 is separated from the original.
Scanning can be performed so that the optical path length leading to 5 is always constant.

The CCD 19 constituting the photoelectric conversion section 7 includes a plurality of photoelectric conversion elements arranged in a line, and photoelectrically converts one line of reflected light from scanning an original. The image electrical signal output from the CCD 19 is processed by the image processing circuit 20 and output as a signal for driving the TPH 21 provided in the image forming section 8.

The image forming section 8 includes a TPH 21, a platen drum 22, an ink ribbon 23, and the like.

The platen drum 22 has a periphery made of an elastic body such as rubber, and functions as a platen roller for the TPH 21. Further, a plurality of pressure rollers 24 are provided around the platen drum 22 in order to prevent the wound paper P from floating up from the platen drum 22.

The TPH 21 is disposed diagonally below the left side of the platen drum 22 in the figure, and an ink ribbon 23 as an image forming medium is interposed between the platen drum 22 and the TP) I21. The cores 25 and 26 of the ink ribbon 23 are connected to a drive shaft of a motor (not shown) via a drive force transmission mechanism (not shown), and are rotated as required.

Further, a winding core 25° 26 around which the ink ribbon 23 is wound is housed in an ink ribbon cartridge 27.

A paper feed roller 28 is provided at the bottom of the main body 1, and is configured to take out the sheets P stored in the paper feed cassette 5 one by one. The paper P taken out by the paper feed roller 28 is transported toward the platen drum 22 by a pair of transport rollers 29, and is wound around the outer periphery of the platen drum 22 by a paper gripper 30 and a pressure roller 24. Note that a multi-threaded sheet feeding device 31 is provided at the upper part of the sheet feeding cassette 5, so that the sheet P can be manually fed 17 and wound around the platen drum 22. Then, the paper P whose leading end is fixed by the paper gripper 30 is wound around the outer circumference by the rotation of the platen drum 22 in the direction shown by arrow B.
After the tip passes the printing area, TPH2] is moved to the cam 32.
As the platen drum 22 rotates, pressure is applied to the platen drum 22, and printing is performed.

When printing is completed, the pressure of the TPH 21 on the platen drum 22 is released, the ink ribbon 23 is wound up by a predetermined amount, and a new ink layer is positioned. Repeat the operations described above.

When printing 91 sheets, the trailing edge of the paper P is the guide 33 for paper ejection.
Rotate the platen drum 22 in the direction of arrow B until it reaches , then rotate the platen drum 22 in the opposite direction with arrow C.
direction, the rear end of the paper P is separated from the platen drum 22 by a separation claw (not shown), and guided to the paper discharge guide 33. Finally, the leading edge of the paper P is released from the gripper 30, and guided by the paper discharge guide 33, the paper P is ejected onto the paper discharge tray 4 J-11.

In the figure, reference numeral 34 is a cooling fan for preventing the temperature inside the main body 1 from rising, and reference numeral 35 is a power supply.

FIG. 1 shows the structure of an ink ribbon 23, which is a feature of this embodiment. In the figure, transparent ink layers 23b and colored ink layers 23c of a predetermined length are alternately provided on a base film 23a constituting an ink ribbon 23 in parallel to the width direction.

Next, the operation of this embodiment will be explained. First, as described above, T is applied to the entire surface of the paper P wound around the outer circumference of the platen drum 22.
Transparent ink layer 2 of ink ribbon 23 by driving PH21
3b onto paper P.

At this time, the platen drum 22 has rotated approximately once. At this point, release the pressure on the TPH 21 once and press the ink ribbon 2.
3 is wound up by a predetermined amount, and the beginning of the colored ink layer 23c is determined. Next, the platen drum 22 is similarly rotated again in the direction of the arrow B, and as shown in FIG. Transfer 23c.

At this time, by forming the transparent ink with an ink having a low melting point, the activated colored ink 52 becomes the transparent ink 5]
is melted and transferred to the surface of the paper P as a unit.

Even when the surface smoothness of the binding paper P is low, the colored ink 52 can be transferred with high transfer probability.

FIG. 4 is a diagram showing the relationship between Beck's smoothness and transfer probability. As is clear from the figure, when the paper P is plain paper, the Bekk smoothness is around 5.0, but when it is coated paper with transparent ink 51 formed on the surface, it can be around 10. . Therefore, the transfer probability can be set to approximately 00%.

Further, as shown in FIG. 5, a multicolor ink layer 23d is formed on the base film 23a of the ink ribbon 23.

23e, it is preferable to increase the thickness of the ink layer in the order of strokes, and at the same time, increase the pressure to suppress TPH2] against the platen drum 22 in order. For example, when the coating amount of the transparent ink layer 23b is 2.5 g/ry or less, the coating amount of the colored ink layer 23d, one for each color, is 3 g/ry.
? The following shall apply. As a means to change the pressure, T P
To press H21] A variable pressure cam is provided at 0.

〔Effect of the invention〕

As explained above, according to the present invention, a transparent ink layer is formed on an ink ribbon which is an image forming medium, and after this transparent ink layer is transferred to the surface of paper which is an image forming medium, the two sides thereof are Since the colored ink layer is transferred, the colored ink can be transferred with a high transfer probability even to paper with low smoothness, and high-quality copies can be made.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing the structure of an ink ribbon according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view illustrating the ink transfer function, and FIG. 3 is a thermal transfer copying machine to which this embodiment is applied. 4 is a diagram showing the relationship between Bekk smoothness and transfer probability. FIG. 5 is a longitudinal sectional view showing the structure of an ink ribbon according to another embodiment of the present invention. ]... Image forming device (copying machine main body) 21... Heating means (thermal head/TPH) 22...
- Supporting means (platen drum)] 1 3... Image forming medium (ink ribbon) 3b... Transparent ink layer 3C... Colored ink layer... Image forming medium (paper)

Claims (1)

[Claims] An image forming medium and an image forming medium having a colored ink layer formed on its surface are sandwiched between a drum-shaped support means and a heating means having a plurality of heat generating elements, and the heat generating elements In an image forming apparatus that generates heat by supplying power to the image forming medium and transfers the colored ink layer onto the image forming medium to form an image, a transparent ink layer is formed on the surface of the image forming medium, and the transparent ink layer is An image forming apparatus characterized in that the colored ink layer is transferred onto the upper surface of the image forming medium after the colored ink layer is transferred onto the surface of the image forming medium.