JPH02210351A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a gradation change without deteriorating resolution and to print on plain paper by composing a screen drum of a base material, a contact screen layer whose light absorptivity changes on the base material and a protective layer possessing lipophilic property and/or hydrophilic property with respect to the layer. CONSTITUTION:The screen drum 110 is composed of the base material 111, the contact screen layer 112 which is placed on the base material 111 and has the light absorptivity changing in the form of a contact screen and the protective layer 113 which is placed on the contact screen layer 112 and has lipophilic property and/or hydrophilic property. A latent image agent applied to the screen drum 110 selectively evaporates by light irradiation to form a latent image. Powdery ink is applied on the latent image to form an image. An area to which the powdery ink is applied can be changed in analog terms according to the quantity of irradiating light and the light absorptivity. Consequently, a gradation change can be obtained without deteriorating resolution, and an image can be printed on plain paper.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an image forming apparatus capable of producing fine images on plain paper.

(Prior art) Conventionally, a recording device (printer) that outputs an image
There are laser beam printers (LBP), inkjet printers, thermal transfer printers (TTP), etc., but these printers require an intermediate
jl (grayscale) expression is essential, and all are done using the constant dot area gradation method (
A+ll+ J atre et al.

”Co1or 1ard Copy for
Co@puter Systems” 51
0°vol, 24. No. 3.1983; Hiroaki Kodera, "Color Reproduction in Digital Printing" Journal of the Institute of Image Electronics Engineers, vol.

14, No. 5i 1985).

(Problem to be solved by the invention) However, in the conventional constant dot area gradation method described above, halftones are expressed using a plurality of pixels arranged in a 7-trix pattern as one unit. On the other hand, the sublimation dye thermal transfer method 1, which has been developed in recent years, uses the fi degree modulation method, so it can produce images as fine as photographs. Although it is possible to output a combined image, it requires the use of special transfer paper, ink film, etc., and it is not possible to write it on the support paper, so the cost of consumables is high.
), and among the halftone expression methods, there is also a method called the area gradation method, which is based on the two-note method. This method, which is used in normal printing, does not cause any deterioration in resolution when expressing halftones, but the mechanism becomes complicated because it is necessary to change the area of the dots.

The present invention solves the problems mentioned above, makes it possible to record on conventional paper, and makes it possible to express high-quality halftones without deteriorating resolution. aim at something.

(Means for Solving the Problem) To achieve this, the present invention provides a scrim drum and a supply of a latent image agent that is transparent, photovolatile, and oleophilic or hydrophilic in proportion to the scrim drum. a latent image forming section that selectively evaporates the latent image agent by irradiating light to form a latent image; and a transfer section that applies powder ink to the latent image to form an image. That's how it is.

And, "2. The screen drum includes a base material, and"
- Consisting of a contact screen layer whose light absorption rate changes like a contact screen, and a protective layer between the contact screen layers that has lipophilicity, hydrophilicity, or a combination of both properties. be done.

If the latent image agent is aqueous, the powder ink is made lipophilic, and when the latent image agent is lipophilic, the powder ink is made hydrophilic.

In addition, the powder ink may be made to have a "smearing property" with respect to the latent image agent described in 1-. A latent image agent supply section that applies a photovolatile, lipophilic or hydrophilic latent image agent, and a latent image forming section that selectively evaporates the latent image agent by irradiating light to form a latent image. and a transfer section that applies powder ink to the latent image to form an image, and the screen drum is located on the base material and the 8811 material and has a contact screen shape with light absorption rate. It is composed of a contact screen layer with varying properties and a protective layer on top of the contact screen layer that is either philic, oily, hydrophilic, or has both of these properties.
The latent image agent coated on the screen drum is selectively evaporated by light irradiation to form a latent image, and powder ink is applied to the latent image to form an image.

Then, the area to which the powder ink is applied can be changed in an analog manner depending on the amount of irradiated light and the magnitude of the light absorption rate.

(Example) Hereinafter, an example of the present invention will be described in detail based on FIGS. 1 to 5.

FIG. 1 shows a cross-sectional view of an image forming bag π showing the first embodiment of the present invention. In FIG. be. 120 is a latent image agent supply section, which supplies latent image agent if! 123
A latent image agent immersed roll 122 containing a latent image agent 124 and immersed in the latent image agent 124, and the latent image agent immersed roll 1
22 and a latent image agent coating roll 121 that receives the latent image agent 124 and applies the latent image agent 124 to the screen drum 110.

The latent image agent 124 can be made of a variety of materials, but it must be oleophilic or hydrophilic, colorless enough to transmit light, especially infrared radiation, from the printing head to the drum surface; It is necessary that the area on the drum surface that receives the light from the print head has the property of evaporating and dissipating faster than other areas. For this purpose, for example, as lipophilic substances, true oils such as essential oils, vegetable oils and mineral oils, or oily substances such as glycerin and glycol are used.

A print head 131 is disposed in the latent image forming section 130, and the print head 131 is a device capable of modulating the main scanning direction and brightness in an analog manner, such as a CRT.

Further, the developing section 140 develops the latent image formed by the latent image forming section 130 using ink 144.

The developing section 140 is equipped with an ink tank 143 containing lipophilic or hydrophilic ink 144, and the ink immersion roll 1
42 and an ink application roll 141 to supply ink 144 to the screen drum 110.

The transfer section 150 consists of a transfer paper 151 and a platen 152. Further, the cleaner section 160 has a blade 161.
or latent image agent] 24. It consists of a roller that is highly absorbent to ink and the like.

Next, FIG. 2 shows a sectional view of the screen drum 110.

The screen drum 110 has contacts and contacts on the base material 111.
It is formed by stacking a screen layer 112 and a protective layer 113, and the surface of the protective layer 113, that is, the surface of the screen drum 110, is treated to be hydrophilic, lipophilic, or have both properties.

The contact screen layer 112 is a layer whose absorption rate for absorbing light from the print head 131 changes sinusoidally in both the main scanning direction and the sub-scanning direction, for example, a layer in which a change in gray scale is depicted. . In addition, protective layer 1
13 is made of a material that transmits the light from the print head 131.

Next, FIG. 3 shows a printing process by the image forming apparatus having the above configuration.

In FIG. 3, a cylindrical screen drum 110 is stretched out into a flat surface, and an image is formed from the left end to the right.

That is, first, the latent developer supply section 120 supplies a thin latent developer Jl1.
25 is formed, and the excess latent image agent 12 is removed in the latent image forming section 130.
4 is evaporated and a latent image (negative image) 126 is formed.

Subsequently, in the developing section 140, the ink 144 is transferred to the area not covered by the latent developer 124, and development is performed.

Therefore, the latent image agent 124 and the ink 144 are selected to have the property of repelling each other. That is, when the latent image agent 124 is hydrophilic, the oleophilic ink 144 is used, and when the latent image agent 124 is oleophilic, the hydrophilic ink 14 is used.
4 are selected respectively.

Next, the image formed on the screen drum 110 is transferred onto a transfer paper 151 in a transfer section 150. Here, since the latent image agent 124 has low viscosity and high volatility, it quickly penetrates into the paper material and dries after the transfer. Also, transfer paper 1
The ink 144 and latent image agent 124 remaining on the screen drum 110 without being transferred to the screen 51 are wiped off by the cleaner section 160, and the screen drum 110 returns to its initial state.

Next, the process of latent image formation is shown in Figure 4. Figure 4 (a) is a diagram of the initial state of the screen drum, Figure 4 (b) is a diagram of the light receiving state of the screen drum, and Figure 4 (c) is a diagram of the screen drum's light receiving state. FIG. 4(d) is a diagram showing the start of evaporation of the latent image agent on the screen drum, and FIG. 4(d) is a diagram showing the end of evaporation of the latent image agent on the screen drum.

In FIG. 4(a), a thin layer 12 of a latent image agent 124 is shown.
5 is formed on the surface of the protective layer 113 of the screen drum 110. The sinusoidal waves appearing in the contact screen layer 112 are reflected by the printhead 131 on the main scan line.
The print head 131 is scanned while changing the amount of light to correspond to the density of the image to be printed, as illustrated in FIG. 4(b).

Here, both the latent image agent 124 and the protective layer 113 are translucent, and the light from the printing layer 131 is directly irradiated onto the contact screen layer 112, where it is absorbed and reflected. In portions of the contact screen layer 112 where the light absorption rate is high, enough thermal energy is generated from the contact screen layer 112 to evaporate the latent image agent 124 even with a small amount of light. On the other hand, in areas where the absorption rate is low, even if a large amount of light is applied, most of it will be reflected, and the latent image agent 124 will not evaporate.

Therefore, the latent image agent 12 on the surface of the screen drum 110
4 is a portion Vl+Vz-1+V4 where the absorption curve S is below the light intensity curve vAL, with the point where the absorption curve S and the light intensity curve intersect as a reference as shown in FIG. 4(c).
evaporates. That is, the latent image agent 124 forms a latent image 126 while changing its evaporation rate with respect to changes in the amount of light (see FIG. 4(d)).

Next, FIG. 5 shows a printing process in an image forming apparatus showing a second embodiment of the present invention.

In the figure, the surface of the screen drum 210 is lipophilic or hydrophilic, while in the latent image supply section 220, a latent image agent 221 is applied to the surface of the screen drum 210 to form a thin layer 225 of the latent image agent. be done.

Here, the latent image agent 221 is also lipophilic or hydrophilic,
Moreover, it is formed from a translucent solvent that is visible to the drum.

In the latent image forming section 230, the latent image 2 is formed using the same principle as described above.
However, unlike the first embodiment, the latent image 226 is formed as a positive image.

Further, in the developing section 240, development is performed using powder ink (toner) 244. Powdered ink 244 moves from toner application roll 241 to latent image 226 on screen drum 210 due to its "wettability." Therefore, the powder ink 244 is soluble in the latent image agent 221, and is dissolved or dispersed in the latent image agent 221 before being transferred to the transfer paper 251 in the transfer section 250.

In the transfer section 250, the latent image agent 221 and the powder ink 244 are both transferred onto the transfer paper 251. The latent image agent 221 and powder ink 244 remaining on the surface of the screen drum 210
is wiped off by the cleaner section 260.

Note that the present invention is not limited to the above embodiments (
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described in detail above, according to the present invention, a scrim drum and a latent image agent that is transparent, photovolatile, and lipophilic or hydrophilic are coated on the scrim drum. a latent image forming section that selectively evaporates the latent image agent by irradiating light to form a latent image; and a transfer section that applies powder ink to the latent image to form an image. The screen drum has a base material, and a contact screen on which the light absorption rate changes like a contact screen on the base material.
It is composed of a screen layer and a protective layer that is oleophilic, hydrophilic, or has both properties on top of the contact screen layer, so that the latent image agent coated on the screen drum can be Selective evaporation forms a latent image, and powder ink is applied to the latent image to form an image.

Then, the area to which the powder ink is applied can be changed in an analog manner depending on the amount of irradiated light and the magnitude of the light absorption rate.

Therefore, it is possible to obtain gradation changes without sacrificing resolution, and printing on plain paper is also possible.

[Brief explanation of the drawing]

1 is a sectional view of an image forming apparatus according to a first embodiment of the present invention, FIG. 2 is a sectional view of the screen drum, and FIG. 3 is a view showing a printing process by the image forming apparatus of the present invention. Figure 4 shows the process of forming a latent image, Figure 4 (a) shows the initial state of the screen drum, Figure 4 (b) shows the light receiving state of the screen drum, and Figure 4 (c) shows the screen drum in its initial state. FIG. 4(d) is a diagram showing the start of evaporation of the latent image agent, FIG. 4(d) is a diagram showing the end of evaporation of the latent image agent in the screen drum, and FIG. 5 is a diagram showing the printing process in an image forming apparatus according to a second embodiment of the present invention. It is a diagram. 110, 210... Screen drum, 111... Base material, 112... Contact screen layer, 113...
・Protective layer, 120° 220...Latent image agent supply section, 124
．． 221...Latent image agent, 125.225...Latent image agent thin layer, 126.226...Latent image, 130.230...
Latent image forming section, 131...Print head, 140.2
40...Developing section, 144.244...Powder ink,
150.250... Transfer section, 151, 251... Transfer paper, 152... Platen, 160.260... Cleaner section. Patent applicant: Oki Electric Industry Co., Ltd. Agent: Patent attorney: Makoto Kawai (1 other person) First invention of the present invention
Fig. 2 shows the process of forming a row on the 1' side of the drum; Fig. 1;

Claims (3)

[Claims] (1) (a) a screen drum; (b) a light-transmitting, photovolatile material on the screen drum;
(c) a latent image forming section that selectively evaporates the latent image agent by irradiating light to form a latent image; d) a transfer section that applies powder ink to the latent image to form an image; (g) a contact screen layer on which the light absorption rate changes as shown in FIG.
An image forming device comprising a protective layer that is hydrophilic or has both of these properties. (2) The image forming apparatus according to claim 1, wherein the powder ink is made lipophilic when the latent image agent is hydrophilic, and the powder ink is made hydrophilic when the latent image agent is lipophilic. (3) The image forming apparatus according to claim 1, wherein the powder ink has "wettability" to the latent image agent.