JP3174602B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-melt type ink-jet recording apparatus, and more particularly, to a hot-melt ink jet recording apparatus, in which an intermediate transfer member is disposed between an ejection nozzle for ejecting hot-melt ink and a recording medium. Further, the present invention relates to a hot-melt type ink jet recording apparatus which records on a recording medium via a recording medium, and further has means for detecting the thickness of ink on the intermediate transfer body.

[0002]

2. Description of the Related Art A hot-melt type ink-jet recording apparatus is a recording apparatus in which a hot-melt ink which is solid at room temperature and becomes liquid by heating is heated and pressurized at the time of printing, and is recorded as an ink droplet on a recording medium. As an ink jet recording apparatus, there is a method using a liquid oil ink at normal temperature as a recording medium, and the oil ink solidifies when stored in a recording head for a long period of time and causes clogging of an ejection nozzle or ink on a recording surface. However, hot melt inks do not have these problems, while there are problems such as soiling if touched before they are not dried. On the other hand, the melted and ejected ink solidifies before penetrating into the recording medium, and thus has problems such as easy peeling.

The following are known documents of the prior art relating to the present invention. (1) "Hot melt inkjet recording apparatus with a fixing mechanism" in JP-A-63-205241. (2) "Hot-melt inkjet printer" in JP-A-1-278361.

[0004] The former is a hot-melt ink jet recording apparatus provided with a fixing mechanism for recording on recording paper and fixing the hot-melt ink adhered thereto by heating or pressing again. In the latter, the printing paper on which the hot melt ink has been ejected and recorded is fed by a printing paper feeding device, and a heating device is provided at any position in a downstream region from a position immediately before a printing position in a feeding direction of the printing paper. This is a hot-melt ink jet recording apparatus that heats the printing paper recorded by recording.

[0005] In any of the above-described hot-melt ink jet recording apparatuses, the fact that the ink droplets ejected from the ejection head are cooled during the flight before reaching the recording paper and the fixing property is deteriorated is determined in advance by recording the recording paper before recording. It is intended to improve the fixability of the ink by utilizing the fact that the ink is heated before or after recording and penetrates the recording paper. However, in such a method, since the fixing property changes depending on the type of recording paper, it is necessary to increase the temperature control accuracy in order to keep the fixing property constant. This leads to an increase in size and cost of the apparatus. Since the entire recording paper is heated, the cooling time for fixing the ink on the recording paper also becomes longer, and conversely, the fixability deteriorates. This is because the temperature is high when the ink comes into contact with the recording paper, and then the ink is cooled in a short time to improve the fixability of the ink. When the ejection head body is heated, the vicinity of the platen is also heated, so that the operator must be careful not to contact the platen. For this reason, a device or the like for preventing contact is required, which is expensive.

Further, as a known document of the prior art relating to the present invention, there is a "hot melt ink transparent image" in Japanese Patent Application Laid-Open No. 1-502016. OHP (Overhead Projectors) made of polyester or acrylic transparent sheet material
When hot-melt ink is ejected onto a film and recorded, the hot-melt ink does not penetrate into the film, so it forms a raised shape (ink spot) regardless of the heating temperature. Deteriorates. In the "transparent hot melt ink image", in order to reduce the lens action, a coating agent having a refractive index substantially the same as that of the ink spot is applied to the ink on the film to correct the swelling shape of the ink spot. However, this method increases the size of the apparatus and increases the cost. On the other hand, in order to remove the lens effect of the ink spot, there is a method of flattening the ink on the OHP film by pressing the ink in a solid state.
In this case, since a large pressure is required, the apparatus becomes complicated.

[0007]

The present invention has been made in view of the above-mentioned circumstances, and (1) has excellent thermal responsiveness without using a high-precision temperature control device, and fixes ink without being affected by the type of recording paper. (2) Deterioration of a projected image due to an ink spot formed on an OHP transparent sheet is eliminated by a device having a simple configuration.
(3) It is an object of the present invention to provide an ink jet recording apparatus having a thickness detecting means for making the three-dimensional shape of an ink spot formed on an OHP transparent sheet uniform without being affected by temperature conditions. It is a thing.

[0008]

To achieve the above object, the present invention provides:
(1), a heating device for heating and melting the hot-melt ink, and ejecting head that ejects a heated molten ink, injection
An intermediate transfer member for receiving the ejected ink, and an
Hotmelt consisting of transfer means for transferring ink to recording paper
In the ink jet recording apparatus, the intermediate transfer member
Before transferring the shape of the ink received in
Be characterized by having an ink deformation means for reduction, or (2) an intermediate receiving a heating device for heating and melting the hot-melt ink, and ejecting head that ejects a heated molten ink, the jetted ink A hot-melt ink jet recording apparatus comprising: an ink shape deforming means for changing the shape of the ink received on the transfer body and the intermediate transfer body; and a transfer means for transferring the ink on the intermediate transfer body to recording paper. Having an ink thickness detecting means for detecting the above ink thickness distribution; and ( 3 ) controlling the ink shape deforming means based on the detection output of the ink thickness detecting means in ( 2 ). In addition, the shape of the ink on the intermediate transfer body is changed. Hereinafter, a description will be given based on examples of the present invention.

FIG. 1 is a view for explaining an embodiment of an ink jet recording apparatus according to the present invention. In the drawing, 1 is an ejection head, 2 is a main body, 3 is a nozzle, 4 is a liquid chamber (ink), Is a heating device, 6 is a piezoelectric ceramic, 7 is an intermediate transfer member, 8 is a fixing heater, 9 is a cleaning heater, 10 is a cleaner, 11 is a paper feed roller, 12 is a driven roller, 13 is a platen, and 14 is recording paper. (Recorded body).

In the drawing, the ejection head 1 has an ink droplet 1
5 is a main element of the recording apparatus for ejecting the ink, and its main part is composed of the main body 2, the heating device 5, and the piezoelectric ceramic 6. The main body 2 is a casing made of a stainless metal such as stainless steel and has a liquid chamber 4 for storing ink and a nozzle 3 communicating with the liquid chamber 4. The ink is a hot melt ink in which a dye is mixed with fatty acid amide, paraffin, or the like, and solidified at room temperature and liquefied by heating. The heating device 5
The solid hot melt ink contained in the liquid chamber 4 is heated at a constant temperature to be in a liquid molten ink by being insulated and in contact with the main body 2. The piezoelectric ceramics 6 is fixed to the wall surface of the main body 2 and is a driving unit for ejecting ink droplets 15 from the nozzles 3. The piezoelectric ceramics such as PZT (lead zirconate titanate) is used as a driving source by a piezoelectric strain caused by voltage application. I have.

The intermediate transfer member 7 is formed of an endless belt made of a heat-resistant resin such as polyimide, and is wound around an outer periphery of a paper feed roller 11 and a driven roller 12 disposed in parallel in a ring shape. The driven roller 12 is disposed at a position facing the nozzle 3, and the paper feed roller 11 is driven to rotate in the direction of arrow R by a drive motor (not shown), and moves the intermediate transfer body 7 in the direction of arrow P according to the rotation. . The drive roller 11 is disposed to face the platen 13 and
The recording paper is fed in the direction of arrow F while holding the recording paper 4 therebetween. Inside the intermediate transfer member 7 of the endless belt, a fixing heater 8 that rotates in contact with the intermediate transfer member 7 is provided. The fixing heater 8 is constituted by a cylindrical ceramic heater or the like and is a heating means for heating the intermediate transfer member 7. The fixing heater 8 reaches the paper feed roller 11 while the heated portion of the intermediate transfer member 7 is not cooled. It is located on the upstream side of the feed roller 11. Further, a cylindrical cleaning heater 9 and a cleaner 10 are rotatably disposed on the upstream side of the driven roller 12 of the intermediate transfer member 7 so as to sandwich the intermediate transfer member 7 from both sides as necessary. You. At this time, the cleaning heater 9 is located on the inner surface of the intermediate transfer member 7, and the cleaner 10 is located on the outer surface.

Next, the operation of the ink jet recording apparatus having the above configuration will be described. First, the liquid chamber 4 of the ejection head 1
The hot melt ink inside is heated and melted by the heating device 5. When a voltage is applied to the piezoelectric ceramics 6, a piezoelectric strain is generated and the liquid chamber 4 is pressurized. As a result, a pressure wave is generated in the liquid chamber 4, and the melted ink is ejected from the nozzle 3 as a droplet 15. The ejected ink flies onto the intermediate transfer member 7 at a position facing the nozzle 3 on the outer peripheral surface of the driven roller 12, and is cooled.

The cooled ink on the intermediate transfer body 7 moves toward the paper feed roller 11 in the direction of arrow P. During this time, the intermediate transfer member 7 and the ink are heated by the fixing heater 8, and the heated ink is melted again and transferred to the recording paper 14 in a liquid state. The heating temperature of the fixing heater 8 is determined in consideration of the moving speed of the intermediate transfer member 7 so that the ink temperature during transfer is constant. Since the ink may remain on the intermediate transfer body 7 after being transferred to the recording paper 14, the remaining ink is heated by the cleaning heater 9 and removed by the cleaner 10. However, the cleaning heater 9 and the cleaner 10 are provided as needed.

FIG. 2 is a diagram for explaining another embodiment of the ink jet recording apparatus of the present invention.
Is a heater for rolling, 17 is a roller for rolling, 18 is OHP
(Overhead Projectors) In the film, portions having the same functions as those in FIG. 1 are denoted by the same reference numerals.

In the drawing, a rolling heater 16 is a heating element such as a ceramic heater in a cylindrical state similar to the fixing heater 8, and is rotatably disposed on the inner surface of the intermediate transfer member 7 upstream of the fixing heater 8. ing. The rolling roller 17 is a cylindrical body made of a porous material impregnated with silicon rubber or silicone oil, and is rotatably disposed so that the intermediate transfer body 7 can be moved in cooperation with the rolling heater 16. Pressing with the specified pressure.

Next, the operation of the ink jet recording apparatus shown in FIG. 2 will be described with reference to FIG. FIG. 3 is a diagram showing a cross-sectional shape of the ink at positions (A) and (B) in FIG. The ink droplets ejected from the nozzles 3 of the ejection head 1 and flying on the intermediate transfer member 7 are cooled,
At the position A downstream of 2, an ink spot having a convex lens shape in cross section as shown in FIG. Next, the ink rolling heater 16 on the intermediate transfer body 7
The ink that has been heated to a temperature near the melting point of the hot melt ink and softened by heating is rolled into a flat plate by the rolling roller 17 and flattened as shown in FIG. Since the rolling roller 16 is impregnated with silicon rubber or silicone oil, the ink on the intermediate transfer body 7 does not peel off without causing ink to adhere to the rolling roller 16 and no defect occurs. The flattened hot melt ink is heated again by the fixing heater 8 and transferred to the OHP film 18 at the transfer section.

As described above, the intermediate transfer member 7 is provided, and the hot melt ink ejected and fixed on the intermediate transfer member 7 is pressurized, reheated, and stretched to expand the hot melt ink.
Deterioration of an OHP film projected image due to a lens action pointed out in -502016 can be prevented. However, simply by pressurizing and heating the solidified hot melt ink to flatten it, there is no detecting means for detecting the shape of the ink, and the effect cannot be correctly evaluated. This is because the shape of the elongated ink changes depending on the environmental temperature and the temperature in the printing apparatus. In order to eliminate these effects, a detecting means for detecting the shape of the ink is provided, and the heater 1 for rolling is provided based on a detection signal of the detecting means.
The shape of the ink may be controlled by feeding back to No. 6.

FIG. 4 is a view for explaining still another embodiment of the ink jet recording apparatus according to the present invention. In the figure, 19 is a thickness detecting means, 20 is a light emitting section, and 21 is a light receiving detecting section. 2 are denoted by the same reference numerals as in FIG.

In the drawing, the thickness detecting means 19 includes the positions of the rolling heater 16 and the rolling roller 17 and the fixing heater 1.
8 and a light emitting unit 20 and a light receiving detecting unit 21. The light emitting section 20 and the light receiving detection section 21 are arranged to face each other with the intermediate transfer body 7 interposed therebetween. The light-emitting unit uses light-emitting elements such as a semiconductor laser and an LED (light-emitting diode), and emits parallel light from these light-emitting elements via an optical system (not shown). The light receiving detector 21 includes a CCD imaging device (Charge coupled device).
e image sensor) is used. The ink jet recording apparatus shown in FIG. 4 is obtained by adding the thickness detecting means 19 to the ink jet recording apparatus shown in FIG.
The operation until the image is transferred to the OHP film 18 via the intermediate transfer member 7 is the same.
The operation of will be described.

First, the shape and the optical effect of the hot-melt ink jetted in a liquid state on the surface of the intermediate transfer member 7 will be described. FIGS. 5A, 5B and 5C are diagrams showing the refraction of light due to the shape of the hot melt ink on the intermediate transfer member.
5A illustrates refracted light when the curvature radius ra is small, FIG. 5B illustrates refracted light when the curvature radius rb is large, and FIG. 5C illustrates refracted light when the curvature radius rc is infinite (flat). Shows the refraction of light due to the shape of the hot melt ink, especially three-dimensional swelling.

FIG. 5A shows the refracted light La of the parallel light Lp incident on the hot melt ink 4a having the radius of curvature ra.
FIG. 5B shows a hot melt ink 4 having a radius of curvature rb.
b shows the refracted light Lb of the parallel light Lp incident on b.
When the refracted light La and the refracted light Lb are compared, the refracted light La has a large refraction angle and is easily scattered, and when this is transferred to an OHP film, the projected image deteriorates. FIG. 5B shows a hot melt ink having a radius of curvature ra <rb, so that the refraction angle is small, but the projected image transferred to the OHP film is deteriorated. On the other hand, in FIG. 5C, since the hot melt ink 4c is a film having a uniform thickness, no refraction of light occurs and O
When transferred onto an HP film, a good projected image is obtained.

In the thickness detecting means 19, the light emitting section 20 and the light receiving detecting section 21 are arranged opposite to each other with the intermediate transfer member 7 interposed therebetween.
In the light emitting section, the parallel incident light Lp illustrated in FIG. 5 is projected onto the hot melt ink on the intermediate transfer body 7. The refracted light varies depending on the shape and thickness of the hot melt ink.
Are obtained as refracted lights La, Lb, and Lc. This refracted light is converted to C
Light receiving detector 2 with CD (Charge Coupled Device)
1, the photoelectric conversion is performed, and the effective light receiving surface of the CCD at this time is selected to be larger than the diameter D of the hot melt ink on the intermediate transfer member 7. The electrical signals detected and photoelectrically converted by the light receiving detection unit 21 are hot melt inks 4a to 4c.
Therefore, by controlling the rolling heater 16 based on the electric signal, it is more reliable than controlling the rolling heater 16 by indirectly measuring the environmental temperature and controlling the rolling heater 16 based on the electrical signal. The hot melt ink in the form of a film having a uniform thickness as shown in c) can be transferred.

FIG. 6 is a view for explaining still another embodiment of the ink jet recording apparatus according to the present invention. In the figure, reference numeral 22 denotes a heater control circuit, and portions having the same functions as those in FIG. The same reference numbers are given.

In the drawing, the light receiving detection unit 21 is installed at a fixed distance L from the intermediate transfer body 7. The light emitting unit 20 projects parallel light onto the hot melt ink 4P having the diameter D on the intermediate transfer body 7, and the parallel light reaches the light receiving detection unit 21 via the intermediate transfer body 7. In the light receiving detector 21,
The electric signal is converted into an electric signal according to the light pattern received according to the transmitted light La to Lb in FIG. 5, and a control signal based on the converted signal is output from the heater control circuit 22, and the control output drives the rolling heater 16. I do. The diameter of the dot is determined by the temperature of the rolling heater 16.
Since the pressure varies depending on the pressing force, the ink thickness is optimized. Since this circuit forms a closed loop between the shape of the hot melt ink 4P, the light receiving detection unit 21, the heater control circuit 22, and the rolling heater 16, the intermediate transfer body 7 always has a stable hot melt ink having a constant film thickness. Can be formed.

[0025]

As is clear from the above description, the ink jet recording apparatus of the present invention has the following effects. (1) Effect corresponding to claim 1: the intermediate transfer member Lee ink
After the flattening, OHP ink remains turned into the flat
Since the image is transferred to a film or the like , an image having a constant pixel diameter can be obtained. (2) according to claim 2 to the corresponding effects: Te on the intermediate transfer member odor
Because it detects the three-dimensional degree of upsurge of the hot-melt ink flattening, it can indirectly detect the quality of hot melt ink to be transferred to an OHP film or the like. (3) Effects corresponding to claim 3 of hot-melt ink
By detecting the thickness so as to control the shape of the ink
Because, ink thickness always is optimized.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining one embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a diagram for explaining another embodiment of the ink jet recording apparatus of the present invention.

FIG. 3 is a diagram showing a cross-sectional shape of ink at positions (A) and (B) in FIG. 2;

FIG. 4 is a view for explaining still another embodiment in the ink jet recording apparatus of the present invention.

FIG. 5 is a diagram illustrating light refraction depending on the shape of hot melt ink on an intermediate transfer member.

FIG. 6 is a view for explaining still another embodiment of the ink jet recording apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Injection head, 2 ... Body, 3 ... Nozzle, 4 ... Liquid chamber (ink), 5 ... Heating device, 6 ... Piezoelectric ceramics, 7 ... Intermediate transfer body, 8 ... Fixing heater, 9 ... Cleaning heater, 10 ... cleaner, 11 ... paper feed roller, 12 ... driven roller, 13 ... platen, 14 ... recording paper (recording body), 1
5 ink drop, 16 heater for rolling, 17 roller for rolling, 18 OHP (Overhead Projectors) film,
19: thickness detecting means, 20: light emitting section, 21: light receiving detecting section, 22: heater control circuit.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-169634 (JP, A) JP-A-3-197143 (JP, A) JP-A-1-133746 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B41J 2/015 B41J 2/325

Claims (3)

(57) [Claims] A heating device for heating and melting the hot melt ink; an ejection head for ejecting the heated and melted ink; an intermediate transfer member for receiving the ejected ink;
A hot means consisting of transfer means for transferring ink on the body to recording paper
In the melt-type ink jet recording apparatus, the intermediate
Before transferring the shape of the ink received by the transfer body to recording paper
An ink jet recording apparatus , further comprising an ink shape deforming means for flattening . 2. A heating device for heating and melting hot melt ink, an ejection head for ejecting the heated and melted ink, an intermediate transfer body for receiving the ejected ink, and changing the shape of the ink received on the intermediate transfer body. In a hot-melt type ink jet recording apparatus comprising an ink shape deforming means and a transfer means for transferring the ink on the intermediate transfer body to recording paper, the ink thickness detecting means for detecting an ink thickness distribution on the intermediate transfer body is provided. An ink jet recording apparatus characterized by having. 3. The method according to claim 1, wherein the ink shape deforming unit is controlled based on a detection output of the ink thickness detecting unit to change the shape of the ink on the intermediate transfer body.
3. The ink jet recording apparatus according to 2 .