JPH04358840A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device which can form a picture element by an appropriate ink drop on recording paper independently of a type of the recording paper, and can output a high printing quality of excellent rubbing resistance. CONSTITUTION:A basic structure is composed of a head 1 which makes ink discharge as an ink drop, a transfer component 5, and a transfer means 7 which transfers it to recording caper 6. The transfer component 5 is equipped with a temperature control means 8, which controls temperature of the transfer component 5 near a melting point of the ink. Further, the transfer component 5 is equipped with a processing means 9 which applies pores sure between the transfer component 5 and the recording paper 6 and a cleaning component 11 which removes the ink having remained on the transfer component 5.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention heats and melts ink, which is solid at room temperature, into a liquid, and when print data is input, the ink is ejected as droplets, and these ink droplets are applied to recording paper. The present invention relates to an image forming apparatus using an inkjet method for forming dots.

0002

[Prior Art] Ink that is solid at room temperature is made of wax or resin-based ink containing dyes or pigments and additives, and is heated and melted into a liquid state, and ink droplets are produced when necessary by an external signal. Various types of hot-melt inkjet systems are known that form pixels by ejecting and flying them, and Japanese Patent Application Laid-Open No. 13537/1986 is a method for controlling the size of ink droplets on recording paper.
As shown in Publication No. 0 and Publication No. 2-502175, the temperature of the recording paper is controlled by controlling the temperature of the platen that holds the recording paper, and the hot melt ink droplets formed on the recording paper are The aim was to optimize the shape of ink droplets and increase their adhesion to recording paper by controlling the solidification conditions.

0003

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the ink droplets adhering to the recording paper permeate and spread from the point where they come into contact with the recording paper, so the range of temperature that must be controlled for the recording paper is narrow, and if the temperature is low, At the center of the ink droplets, the ink droplets do not spread sufficiently and solidify to a certain height (several tens of micrometers), so that they are easily scraped off by other recording paper, nails, etc. Furthermore, if the temperature was raised to make the ink droplets adhere sufficiently, they would bleed onto the recording paper, resulting in a deterioration in print quality. Another problem is that it is difficult to control the temperature of the recording paper on the platen regardless of the type of recording paper.

The present invention is intended to solve these problems, and its purpose is to be able to form pixels with appropriate ink droplets on recording paper, regardless of the type of recording paper, and to improve scratch resistance. An object of the present invention is to provide an image forming apparatus that is excellent in quality and capable of outputting high print quality.

[0005]

[Means for Solving the Problems] The image forming apparatus of the present invention is an image forming apparatus that uses ink that is solid at room temperature as a liquid by heating and melting it, and has a head that ejects the ink as ink droplets in response to an external signal. , 1. 2. It is composed of a transfer member that receives ink droplets, and a transfer means that transfers the ink droplets from the transfer member to the recording paper after the transfer member receives the ink droplets.2. The transfer member receiving the ink droplets is provided with temperature control means, and the temperature of the transfer member is controlled near the melting point of the ink.3.
．． 4. The transfer means that transfers the ink droplets from the transfer member to the recording paper after the transfer member receives the ink droplets is constituted by a pressure means that applies pressure between the transfer member and the recording paper.4. It is characterized by comprising a cleaning member that removes ink remaining on the transfer member after transferring the ink to the recording paper.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the image forming apparatus of the present invention will be described below with reference to the drawings.

First, the configuration of an image forming apparatus according to the present invention will be explained using FIG. 1. Reference numeral 1 in the figure is a head that heats and melts ink, which is solid at room temperature, and ejects it as ink droplets in response to an external signal.It has a pressure chamber for pressurizing the ink, and a pressure created by a piezoelectric element, etc. a generating element;
It is composed of a nozzle plate with nozzles for ejecting ink droplets, an ink supply path, etc., and is connected to an ink tank 2 equipped with an ink temperature control means for controlling the temperature of the ink, and is guided by guide shafts 4a and 4b. It is fixed on the carriage 3.

When the image forming apparatus is powered on, the ink in the ink tank 2 and head 1 is melted by the ink temperature control means described above, and the apparatus enters a printing standby state.

There are two types of ink, natural wax-based ink and sulfonamide-based ink, and the compositions will be explained next. Natural wax-based inks include microcrystalline wax, paraffin wax, carnauba wax, behenic acid, dyes or microcrystalline wax, paraffin wax, candelilla wax, behenic acid,
It is a composition mainly containing dye. In addition, sulfonamide inks include para-toluenesulfonamide, 3,4-dimethylbenzenesulfonamide, ethylbenzenesulfonamide, para-N-butylbenzenesulfonamide,
This is a composition mainly containing N-cyclohexyl-paratoluenesulfonamide and a dye.

Here, in response to an external signal, the head 1
The pressure generating element generates pressure in the pressurizing chamber, and ink droplets are ejected from the nozzle. The ejected ink droplets are transferred to a transfer member 5 made of polyimide film, silicone rubber, fluororesin film, etc. and placed opposite to the head 1.
It adheres to the top and solidifies within a few milliseconds. The transfer member 5 is formed in the shape of a belt, moves as printing progresses, and is warmed by a temperature control means 8 formed by a halogen lamp, an infrared heater, a heating wire heater, etc., so that the ink on the transfer member 5 reaches a temperature close to its melting point. temperature rises. Subsequently, the transfer member 5 is guided to a transfer means 7 composed of, for example, two rollers and a pressure means 9 such as a spring, and is transferred to the recording paper 6 taken out one by one from the paper tray 10 and the transfer means 7. The ink on the transfer means 5 is transferred to the recording paper 6.
By transferring the ink under pressure, an appropriate ink height and ink spread can be obtained, resulting in an image with good abrasion resistance. Subsequently, the recording paper 6 is ejected from the image forming apparatus, and a series of image forming operations is completed.

Conventionally, ink droplets ejected from the head 1 were deposited directly on the recording paper 6. Therefore, in the conventional example, in order to obtain an appropriate ink height and spread, the ink droplets were deposited directly on the recording paper 6.
We had to delicately control the temperature of the ink and use the heat to penetrate the ink. The proper shape of ink droplets on the recording paper 6 varies depending on the ink used, but in order to ensure scratch resistance, the ink height should be approximately 1
Experiments have shown that it is desirable that the thickness be 0 μm or less.

The present invention can easily be applied to various types of recording paper 6 by controlling the temperature and pressure during transfer. Also, head 1 due to paper jam or paper abrasion.
In order to prevent damage to the head 1 and deterioration of print quality, etc., the distance between the head 1 and the recording paper 6 needs to be approximately 1 to 2 mm, and the ink ejection speed needs to be fast. In this example, the head 1 and the transfer member 5 can be brought closer to each other by 1 mm or less, and there is no damage to the head 1 due to paper jams, paper scratches, etc., and even if the ink ejection speed is slow, there is no deterioration in print quality. , the head 1 is easy to design, and the image forming apparatus is also easy to design.

The material for the transfer member 5 is polyimide because the temperature of the melted ink is about 90 to 150°C, so it needs to be a material with good heat resistance and is desired to have excellent transferability. It is preferable to use a film, silicone rubber, fluororesin film, etc. processed into a mirror-like state and formed into a belt shape. Further, the temperature of the ink to be heated by the temperature control means 8 during transfer has an appropriate value depending on the composition of the ink used.

Further, if necessary, a cleaning member 11 made of felt material, absorbent cotton, cloth, etc. is arranged to remove ink remaining on the surface of the transfer member 5 after the ink is transferred to the recording paper 6. By applying appropriate pressure to the transfer member 5 using a spring or the like, even higher print quality can be ensured. In some cases, it may be more effective to warm the cleaning member 11.

FIG. 2 is a partial perspective view of an image forming apparatus showing another embodiment of the present invention, in which the transfer member 51 has a hollow roller structure, and is equipped with a halogen lamp, an infrared heater, etc. inside. A temperature control means 81 is arranged to control the temperature of the transfer member 51 to around the melting point of the ink.

The outer periphery of the transfer member 51 is coated with fluororesin, silicone resin, polyimide resin, etc. to maintain a mirror-like surface. As described above, the head 1 is connected to an ink tank 2 and fixed on a carriage 3.
Ink droplets from the head 1 are transferred to a transfer member 51 of a platen, for example.
It is discharged upwards. The ejected ink droplets are held on the transfer member 51 in a dissolved or semi-dissolved state in which only the portions in contact with the air are dissolved.

Subsequently, the ink droplets are conveyed by rotation of the transfer member 51 to a transfer means 71 composed of, for example, a metal roller and a spring (not shown), and the ink droplets are transferred to the recording paper 6 carried from the other side by the transfer means 71. The ink droplets are transferred between the transfer member 51 and the transfer member 51. The moment the ink droplets on the transfer member 51 come into contact with the recording paper 6, they solidify from a melted or semi-dissolved state, and at the same time they spread due to the pressure applied by the transfer means 71, creating an appropriate state of ink droplets on the recording paper 6. be able to. By configuring like this,
The structure of the image forming apparatus may be simpler than the embodiment shown in FIG.

[0018]

Effects of the Invention As explained above, it is composed of a transfer member that receives ink droplets, and a transfer means that transfers the ink droplets from the transfer member to recording paper after the transfer member receives the ink droplets. Therefore, it is possible to provide an image forming apparatus with excellent ink abrasion resistance and high print quality regardless of the type of recording paper.

Furthermore, since the head does not directly face the recording paper, the distance that the ink droplets fly from the head can be shortened, so the flying speed of the ink droplets can be slow, and the head Design is also easier. Furthermore, since damage to the head due to paper jam or paper abrasion does not occur, it is possible to provide an image forming apparatus with higher reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a partial perspective view showing an embodiment of the image forming apparatus of the present invention.

[Explanation of symbols]

1...Head 2... Ink tank 5...Transfer member 6... Recording paper 7...Transfer means 8...Temperature control means 9... Pressurizing means 11...Cleaning member

Claims (4)

[Claims] 1. An image forming apparatus that uses ink, which is solid at room temperature, by heating and melting it as a liquid, comprising a head that discharges the liquefied ink as ink droplets onto a transfer member in response to an external signal, and a head that receives the ink droplets. An image forming apparatus comprising: a transfer member; and a transfer means for transferring the ink droplets received by the transfer member from the transfer member to a recording sheet. 2. The image forming apparatus according to claim 1, further comprising temperature control means for controlling the temperature of the transfer member. 3. The image forming apparatus according to claim 1, wherein the transfer means includes a pressure means that applies pressure between the transfer member and the recording paper. 4. The image forming apparatus according to claim 1, further comprising a cleaning member for removing ink remaining on the transfer member.