WO2006051733A1

WO2006051733A1 - Inkjet printer

Info

Publication number: WO2006051733A1
Application number: PCT/JP2005/020264
Authority: WO
Inventors: Tsutomu Yoneyama
Original assignee: Konica Minolta Medical & Graphic, Inc.
Priority date: 2004-11-15
Filing date: 2005-11-04
Publication date: 2006-05-18
Also published as: JP2006137127A

Abstract

Disclosed is an inkjet printer comprising a recording head for discharging an ink and a transfer belt (7) onto which the ink is discharged from the recording head. The transfer belt (7) is provided with a plurality of recessed portions (8).

Description

Specification

Inkjet printer technology

The present invention relates to an ink jet printer that transfers ink from a transfer member to a recording medium and records an image on the recording medium.

Background art

Conventionally, a transfer type ink jet printer is known as an embodiment of an ink jet printer. This transfer type ink jet printer is configured to eject ink from a recording head toward a transfer body, transfer the ink landed on the transfer body to a recording medium, and record an image on the recording medium. .

A specific example of a transfer type ink jet printer is disclosed in Patent Document 1. The ink jet printer described in Patent Document 1 uses an ultraviolet curable ink as the ink, and irradiates the ink that has landed on the transfer body with ultraviolet rays before transfer, and transfers the ink to a recording medium in a semi-cured state. ing.

Patent Document 1: JP 2001-179960 A

Disclosure of the invention

Problems to be solved by the invention

[0004] However, in the transfer type ink jet printer including the ink jet printer of Patent Document 1, immediately after the ink has landed on the transfer body, the landed inks (dots) cross each other on the transfer body. The phenomenon of adhering to each other (beading) occurs, resulting in a decrease in image quality.

[0005] An object of the present invention is to prevent the occurrence of beading.

Means for solving the problem

[0006] In order to solve the above problems, the present invention includes configurations of the following items.

Item 1 A recording head that ejects ink;

A transfer body that receives the ejection of the ink by the recording head;

With An ink jet printer, wherein a plurality of recesses are formed on the transfer body.

For the ink jet printer described in Item 2, Item 1,

The recording head has a plurality of ejection holes for ejecting the ink as droplets;

An ink jet printer characterized in that the interval between the ejection holes is at least twice the interval between the recesses.

Item 3. In the inkjet printer according to Item 1 or 2,

The ratio of the width of each concave portion to the width of the convex portion between the concave portions adjacent to each other is 3 or more.

Item 4 In the inkjet printer according to any one of Items 1 to 3,

Each of the recesses has a depth to width ratio of 0.3 or less.

Item 5 In the inkjet printer according to any one of Items 1 to 4,

An ink jet printer, wherein the transfer member has a belt shape.

Item 6. The inkjet printer according to any one of Items 1 to 4,

An ink jet printer, wherein the transfer member has a drum shape.

Item 7 In the inkjet printer according to any one of Items 1 to 6,

Transfer means for transferring the ink landed on the transfer body to a recording medium;

An irradiation device for irradiating the recording medium with ultraviolet rays;

With

An ink jet printer, wherein the ink is an ultraviolet curable ink that is cured by being irradiated with ultraviolet rays, and is transferred from the transfer body to a recording medium by the transfer unit, and thereafter receives ultraviolet rays from the irradiation device. .

The invention's effect

According to the inventions described in Items 1 to 7, since the plurality of concave portions are formed on the transfer body, the concave portions and the convex portions corresponding to the gap portions are alternately arranged on the transfer body. Therefore, when the ink ejected from the recording head lands on both the concave and convex portions of the transfer body, the ink on the convex portion moves to the lower concave portion (sliding down) and transfers. Landing on the body On the transfer body, the inks are dispersed in the respective concave portions so as to be separated from each other and are present at a distance from each other. Therefore, it is possible to effectively prevent the occurrence of beading that the inks mix and adhere to each other on the transfer body.

Brief Description of Drawings

FIG. 1 is a side view showing a schematic configuration of an inkjet printer 1.

2 is a perspective view showing a schematic configuration of a transfer device 3. FIG.

FIG. 3 is a plan view showing a configuration on the surface of a transfer belt 7.

4 is a cross-sectional view taken along dotted line A in FIG.

Explanation of symbols

[0009] 1 Inkjet printer

2 Recording media

4 Transfer roller (Transfer means)

7 Transfer belt (transfer body)

8 Recess

9 Convex

10 Recording head

25 Irradiation equipment

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

. However, the scope of the invention is not limited to the illustrated examples.

FIG. 1 is a side view showing a schematic configuration of an inkjet printer 1 according to the present invention.

As shown in FIG. 1, the ink jet printer 1 has a transfer device 3 that transfers ink to a recording medium 2. The transfer device 3 includes a transfer roller 4 that rotates counterclockwise in FIG. 1 and two guide rollers 5 and 6, and an endless transfer belt between the transfer roller 4 and the guide rollers 5 and 6. 7 has been wound. As the transfer roller 4 rotates, the transfer belt 7 rotates counterclockwise in FIG. 1 (see the arrow in FIG. 1).

FIG. 2 is a perspective view showing a schematic configuration of the transfer device 3.

As shown in FIGS. 1 and 2, the transfer belt 7 is composed of the transfer roller 4 and the lengths of the guide rollers 5 and 6. The width is approximately the same. A plurality of concave portions 8, 8,... Are formed on the surface of the transfer belt 7 in a regular manner, and the gap portions of the concave portions 8 are convex portions 9.

The transfer belt 7 also has a natural rubber or synthetic rubber force. When the transfer belt 7 is composed of synthetic rubber, it is preferable to use a material mainly composed of ethylene-propylene rubber, nitrile rubber, etc. as the synthetic rubber.

In addition to the above materials, the transfer belt 7 includes polyimide (PI), polyphenylene sulfide (PPS), polyethersulfone (PES), polyamide (PA), polyethylene terephthalate (PET), polyimide amide ( Plastic material forces such as PIA) may also be configured. When the transfer belt 7 is composed of the above plastic material cover, the transfer belt 7 can be formed by forming a seamless belt of the plastic material by inflation molding or the like and then rolling it. The transfer belt 7 can also be formed by thermally fusing a sheet of plastic material.

[0017] In the present embodiment, the surface of the transfer belt 7 having the above-described material force is the surface of each recess 8 as it is, and each recess 8 has lipophilicity.

[0018] The surface of the convex portion 9 is coated with a fluorine-based resin, and the convex portion 9 has oil repellency. The surface of the convex portion 9 may be coated with a hydrophilic material. For example, a material containing any functional group of OH, -COOH, -NH, and CO (compound) is hydrophilic.

2

It can be applied as a property material.

FIG. 3 is a detailed view showing the surface of the transfer belt 7 and is a plan view of the transfer belt 7.

As shown in FIG. 3, the recesses 8 have a circular shape and are arranged in a matrix at equal intervals. The ratio of the width W2 of each concave portion 8 to the width W1 of the convex portion 9 sandwiched between the two concave portions 8 and 8 adjacent to each other is 3 or more.

The ratio of the width W2 to the width W1 is set to 3 or more because if the ratio of the width W2 to the width W1 is less than 3, the ink adhering to the transfer belt 7 remains on the convex portion 9 and the ink Cannot be dispersed and held in the respective concave portions 8, and when the ink is transferred from the transfer belt 7 to the recording medium 2, the graininess of dots is not uniform, pinholes are easily formed, convex portions 9 A large amount of ink remains on the top and a small amount of ink remains on the surface. This is because the difference in lightness and darkness appears in the image.

FIG. 4 is a cross-sectional view of the surface of the transfer belt 7, and more specifically, a cross-sectional view taken along the dotted line A in FIG.

[0023] As shown in FIG. 4, each recess 8 has a U-shaped cross section, and the ratio of the depth D to the width W2 is 0.3 or less. The cross-sectional shape of each recess 8 may be arcuate or V-shaped.

[0024] The ratio of the depth D to the width W2 is 0.3 or less because the ratio of the depth D to the width W2 is 0.

If it exceeds 3, the depth D with respect to the width W2 of the opening of each recess 8 is too deep, and ink remains in each recess 8 and the transfer efficiency of the ink from the transfer belt 7 to the recording medium 2 is significantly reduced. This is because ink clogging occurs in the concave portion 8.

As shown in FIG. 1, a recording head 10 that ejects ink is disposed above the transfer device 3. The ink ejected from the recording head 10 is an oleophilic ink and is an ultraviolet curable ink that cures when irradiated with ultraviolet rays. The recording head 10 is a line head extending from the front side to the back side in FIG. 1, and ejects ink toward the transfer belt 7 straddled between the guide rollers 5 and 6. A plurality of ejection holes 11, 11,... (See FIG. 3) along the width direction of the transfer belt 7 are arranged in a row at equal intervals in the lower part of the recording head 10. Ink is ejected as droplets.

As shown in FIG. 3, the interval P 1 between the ejection holes 11 of the recording head 10 (the distance between the central portions of the two adjacent ejection holes 11 11) is the interval P 2 between the recesses 8 of the transfer belt 7 It is more than twice the (distance between the central parts of the two adjacent recesses 8, 8).

[0027] The interval P1 is set to be at least twice as large as the interval P2, because the ink droplets discharged from the respective discharge ports 11 can be dispersed in the plurality of recesses 8, 8,. This is because the image quality can be improved or the image quality can be improved by reducing the thickness of the dots.

As shown in FIG. 1, a tallying device 15 for cleaning the transfer belt 7 is arranged on the right side of the transfer device 3. The cleaning device 15 is disposed opposite to the transfer belt 7 between the transfer roller 4 and the guide roller 6 and removes ink remaining on the transfer belt 7 from the transfer belt 7! / RU

[0029] Below the transfer device 3, a transport device 20 for transporting the recording medium 2 is disposed. Transport equipment The apparatus 20 includes a conveying roller 21 that rotates clockwise in FIG. 1 and two guide rollers 22 and 23! /. The transport roller 21 is disposed opposite to the transfer roller 4 of the transfer device 3.

[0030] A recording medium 2 is placed between the transport roller 21 and the guide rollers 22 and 23. When the transport roller 21 rotates, the recording medium 2 passes from the guide roller 22 through the transport roller 21 and the guide roller 23. (See the arrows in Fig. 1).

An irradiation device 25 that irradiates the recording medium 2 with ultraviolet rays is disposed between the conveyance roller 21 and the guide roller 23. The irradiation device 25 has three light sources 26, 26, 26 and a reflector 27. Each light source 26 is a linear light source whose front side force in FIG. 1 extends to the back side, and emits ultraviolet rays when turned on. When each light source 26 is turned on, the ultraviolet light is directly incident on the recording medium 2 from each light source 26 or is reflected by the reflecting plate 27 and indirectly incident on the recording medium 2.

Next, the operation / action of the inkjet printer 1 will be described.

[0033] In a state where the transfer roller 4 and the transport roller 21 are rotated and each light source 26 of the irradiation device 25 is lit, the recording head 10 ejects ink toward the transfer belt 7, and the ink is transferred to the transfer belt. Land on 7 and pass through guide roller 5. Thereafter, when the ink landed on the transfer belt 7 reaches the vicinity of the transfer roller 4, the transfer roller 7 is pressed against the conveying belt 21 while rotating as the transfer means 4, and the ink is used as a transfer body. Transfer from the transfer roller 7 to the recording medium 2.

The ink transferred to the recording medium 2 is also transported to the guide roller 23 as the transport roller 21 rotates, and is cured by being irradiated with ultraviolet rays from each light source 26 in the middle thereof. On the other hand, the ink remaining on the transfer belt 7 without being transferred to the recording medium 2 is transported from the transfer belt 7 toward the guide roller 6 as the transfer belt 7 rotates, and is transferred by the cleaning device 15 during the transport. Removed from roller 7.

Thereafter, the ink jet printer 1 repeats the above operation to record a desired image on the recording medium 2.

In the inkjet printer 1 described above, since the plurality of concave portions 8, 8,... Are formed in a matrix on the surface of the transfer belt 7, the gap portion of each concave portion 8 becomes the convex portion 9, and the transfer is performed. On the surface of the belt 7, the concave portions 8 and the convex portions 9 are alternately arranged. Therefore, When the ink ejected from the recording head 10 lands on both the areas of the concave portion 8 and the convex portion 9 of the transfer belt 7, the ink on the convex portion 9 moves to the concave portion 8 at a lower position (sliding down). The ink that has landed on the transfer belt 7 exists on the surface of the transfer belt 7 in a state where it is dispersed in the recesses 8 and separated from each other so as to be separated from each other.

Specifically, as shown in FIG. 3, four concave portions 8a, 8b, 8c, 8d and convex portions of the gap portions are formed as ink force droplets ejected from one ejection hole 11 with the recording head 10. When landing across the part 9 (see the two-dot chain line), the ink droplet slides down into the concave parts 8a, 8b, 8c, 8d so that the ink on the convex part 9 is separated from each other. It exists as four droplets at a distance from each other. From the above, it is possible to effectively prevent the occurrence of beading on the surface of the transfer belt 7 when the inks cross each other and adhere to each other.

[0038] Further, in the ink jet printer 1, each concave portion 8 has oleophilicity and the convex portion 9 has oil repellency. It is possible to effectively and reliably prevent beading that easily slips down.

[0039] It should be noted that the present invention is not limited to the above-described embodiments, and various improvements and design changes may be made without departing from the spirit of the present invention!

[0040] As one improvement 'design change, the planar shape of each recess 8 may be an elliptical shape, may be a polygonal shape such as a triangular shape or a quadrangular shape, or any other shape. May be present.

As another improvement and design change, a rotatable drum-shaped transfer body having a surface configuration similar to the surface of the transfer belt 7 may be applied instead of the transfer device 3. In this case, the drum-shaped transfer member itself serves as a transfer means to transfer the ink to the recording medium 2 while rotating.

As another improvement / design change, a serial type recording head that moves back and forth in FIG. 1 instead of the recording head 10 may be applied.

Claims

The scope of the claims

[1] a recording head for ejecting ink;

A transfer body that receives the ejection of the ink by the recording head;

With

An ink jet printer, wherein a plurality of recesses are formed on the transfer body.

[2] The recording head has a plurality of ejection holes for ejecting the ink as droplets,

2. The ink jet printer according to claim 1, wherein the interval between the discharge holes is at least twice the interval between the recesses.

[3] The inkjet printer according to [1] or [2], wherein the ratio of the width of each concave portion to the width of the convex portion between the concave portions adjacent to each other is 3 or more.

[4] The inkjet printer according to any one of [1] to [3], wherein each of the recesses has a depth to width ratio of 0.3 or less.

[5] The transfer body according to any one of claims 1 to 4, wherein the transfer body has a belt shape.

V, an ink jet printer according to item 1 above.

[6] The method according to any one of claims 1 to 4, wherein the transfer body has a drum shape.

V, an ink jet printer according to item 1 above.

[7] Transfer means for transferring the ink landed on the transfer body to a recording medium;

With

The ink is an ultraviolet curable ink that is cured by being irradiated with ultraviolet rays, wherein the ink is transferred from the transfer body to a recording medium by the transfer means, and thereafter receives ultraviolet rays from the irradiation device. The inkjet printer according to any one of items 1 to 6 above.