JPH09123430A - Transfer type ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the high quality printed image by a method wherein an ink drop discharged to an intermediate transfer material is held in a state wherein adjacent ink drops separated without becoming united by a fine projection part formed on a surface. SOLUTION: An intermediate transfer material 11 has, for example, a cylindrical drum shape, and a foam layer 111 having a required thickness is formed on its outer peripheral surface. A material constituting the foam layer 111 is formed by kneading silicone rubber, fluororesin or fluororubber, etc., being excellent releasable material with an organic blowing agent and foaming them by treating at a specific temperature. Then, by applying cutting, polishing, etc., to one surface side of the formed foam, fine and many annular projections 112 owing to cells are mutually continuously formed on the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus applied to a facsimile, a copying machine, a printer, etc., and more particularly to a transfer type for transferring an ink image formed on an intermediate transfer member to a recording medium for printing. The present invention relates to an inkjet recording device.

[0002]

2. Description of the Related Art Conventionally, a direct type ink jet recording apparatus for ejecting ink droplets directly from a plurality of nozzles arranged in a recording head onto a recording sheet to perform printing, and an ink droplet ejecting toward an intermediate transfer member. There is known a transfer type ink jet recording apparatus that forms an ink image by transferring the ink image onto a recording sheet to perform printing. In the direct type ink jet recording apparatus, when the recording sheet bends, the nozzle surface of the recording head comes into contact with and becomes dirty. Therefore, it is necessary to consider prevention of bending of the recording sheet.
Such a consideration is not necessary, and it is possible to easily keep the distance between the nozzle of the recording head and the intermediate transfer body constant.

[0003]

The intermediate transfer member used in the above transfer type ink jet recording apparatus may be made of metal or synthetic resin as a material, but the aqueous ink usually used in the above direct type ink jet recording apparatus is used. When ejected toward an intermediate transfer body made of metal or synthetic resin, if the ejected ink droplets come into contact with adjacent ink droplets, they will coalesce due to surface tension and the ink droplets will become a large ball, forming an ink image. The print quality was deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a transfer type ink jet recording apparatus capable of obtaining a high quality printed image.

[0005]

According to the present invention, ink droplets are ejected from the nozzles of a recording head toward the surface of an intermediate transfer member and adhered to the surface of the intermediate transfer member to form an ink image. In a transfer type ink jet recording apparatus for transferring an image to a recording medium to perform printing, the intermediate transfer member has a minute projection formed on the surface (claim 1).

According to this structure, the ink droplets ejected onto the intermediate transfer member are kept in a separated state by the minute protrusions formed on the surface without adjoining ink droplets being merged. A quality printed image is obtained.

Further, the protrusion is formed in an annular shape having a diameter equal to or smaller than the ink droplet (claim 2).

According to this structure, the ink droplets ejected on the intermediate transfer member come into contact with the protrusions formed on the surface at a plurality of points, and due to the frictional force, the adjacent ink droplets are separated without coalescing. It is securely held in a state, so that a high quality printed image can be obtained.

Further, the surface of the intermediate transfer member is a silicone rubber foamed by adding a foaming agent (claim 3).

The surface of the intermediate transfer member is a fluororubber foamed by adding a foaming agent (claim 4).

According to these structures, depending on the amount of the foaming agent added to the silicone rubber or the fluororubber and the foaming conditions, the diameter of the protrusion is formed to be equal to or smaller than that of the ink droplet, and the ink droplet ejected onto the intermediate transfer member is formed. , The minute protrusions formed on the surface come into contact with each other at a plurality of points, and the frictional force ensures that the adjacent ink droplets are securely held in a separated state without coalescing, and that the silicone rubber has good releasability. Alternatively, by using fluororubber, the ink image formed on the intermediate transfer member is preferably transferred to the recording paper,
High quality printed images can be obtained.

[0012]

1A is a front view showing the internal structure of a first embodiment of an ink jet recording apparatus according to the present invention, and FIG. 1B is a state of ink droplets ejected onto an intermediate transfer member. FIG.

This ink jet recording apparatus includes an intermediate transfer body 11 and a recording head 1 facing the intermediate transfer body 12.
2, an ink image is formed on the peripheral surface of the intermediate transfer member 11 by the recording head 12, and the ink image is fed to the paper feeding cassette 13
Printing is performed by transferring the sheet from the sheet to a sheet as a recording medium conveyed through the sheet conveying path 14.

The paper feed cassette 13 stores a recording paper of a predetermined size to which an image is transferred, and a paper feed roller 15 for feeding paper is arranged at the front end. The sheet conveying path 14 has a guide for guiding the sheet fed from the sheet feeding cassette 13 to the intermediate transfer body 11, and has a pair of conveying rollers 16 for conveying the fed sheet and a pair of registration rollers for performing the secondary sheet feeding. 17 are provided.

The intermediate transfer member 1 is provided downstream of the paper transport path 14.
1 is provided, and a sheet conveying path 18, a discharge roller pair 19 and a discharge tray 20 are provided downstream of the intermediate transfer body 11. A recording head 12, a pressure roller 21, and a cleaning device 22 are arranged around the intermediate transfer body 11.

The recording head 12 has a nozzle surface formed on the surface facing the intermediate transfer member 11, and ink is supplied from an ink tank 23 arranged at the lower part of the apparatus via an ink supply tube 24. There is. Also, each nozzle is
For example, a large number of sheets are formed in the paper width direction by at least the paper width, and each is connected to a pressurizing chamber (not shown), and each pressurizing chamber is connected to an ink liquid chamber (not shown) in which ink is further stored.

Further, in the recording head 12, the nozzle surface is arranged at a printing position of a predetermined dimension of, for example, 1 mm from the peripheral surface of the intermediate transfer body 11 at the time of printing, and the ink filled from the ink liquid chamber is pressurized in the pressure chamber. From each nozzle to intermediate transfer body 1
1, the ink droplets 121 are attached to the surface of the intermediate transfer body 11 to form an ink image.

The diameter of the ink drop 121 is set to a predetermined value such as √ (2) times the interval of the ink drop ejected onto the intermediate transfer member 11. The recording head 12 may be of a variable type in which the diameter of the ejected ink droplets is variable.

The intermediate transfer member 11 has, for example, a cylindrical drum shape, and a foam layer 111 having a required thickness is formed on the outer peripheral surface thereof. The material forming the foam layer 111 is
It is formed by kneading silicone rubber, fluororesin, fluororubber, or the like, which is a material having good releasability, with an organic foaming agent, and foaming the mixture by treating it at a predetermined temperature. Then, the one surface side of the formed foam is subjected to cutting, polishing, or the like, so that minute and numerous annular projections 112 due to air bubbles are continuously formed on the surface.

The diameter of the annular projection 112 is preferably 1/2 or less of the diameter of the ink droplet 121 so that the ink droplet 121 does not drop into the concave portion between the projections because it is too large. Further, if it is too small, the surface becomes the same as the smooth surface, so that it is preferably 1/10 or more of the diameter of the ink droplet 121.

Then, as shown in FIG. 1B, the ink droplets 121 ejected in contact with each other on the annular projection 112 of the foam layer 111 on the surface of the intermediate transfer body 11 are maintained in a separated state. As shown in FIG. 3, a large ink ball is not formed by coalescing like the ink droplets 121 ′ ejected in contact with each other on the intermediate transfer body 11 ′ having a smooth surface.

This is a drop of ink 1 for a smooth surface.
Since the frictional force between the surface 21 'and the surface of the intermediate transfer body 11' is small, the surface tension prevails, and the ink droplets 121 'easily move on the surface and coalesce, but when the annular projection 112 is formed on the surface. It is considered that the frictional force becomes larger than the surface tension of the ink droplet 121 because the ink droplet 121 and the surface of the intermediate transfer member 11 contact at a plurality of points.

As the silicone rubber, for example, polydimethylsiloxane, vinyl silicone rubber in which a part of this polydimethylsiloxane is substituted, phenyl silicone rubber or fluorosilicone rubber in which other components are introduced into polydimethylsiloxane, etc. Is used, polytetrafluoroethylene, polychlorotrifluoroethylene, or the like is used as the fluororesin, and vinylidene fluoride-based, tetrafluoroethylene-propylene-based, or the like is used as the fluororubber.

As the foaming agent, azodicarbonamide (ADCA), which can be generally used for resins and rubbers, is used, and especially for silicone rubber, azobisisobutyronitrile (AZDN) is used.

The diameter of the annular projection 112 can be obtained by changing the kind and amount of the organic foaming agent used, foaming conditions such as foaming temperature and pressure. For example, if the amount of the foaming agent is increased or the foaming temperature is set higher, the diameter becomes larger.

The pressure roller 21 is arranged above the intermediate transfer member 11 with its peripheral surface in contact with the intermediate transfer member 11, and applies a required pressure to the contact portion.
The recording paper sandwiched between 1 and the pressure roller 21 is transferred by the applied pressure to the ink image formed on the surface of the intermediate transfer body 11 while being conveyed.

The cleaning device 22 removes the ink remaining on the surface of the intermediate transfer body 11 after the transfer, and is composed of a felt roller 221, a cleaning roller 222, and a take-up roller 223.

The felt roller 221 comprises a cleaning member 224 wound around it.
4 is made of felt, non-woven fabric or the like, and has a width of at least the size of the nozzle row of the recording head 11. A cleaning member 224 is stretched around the cleaning roller 222, and the cleaning roller 222 is arranged to be pressed against the surface of the intermediate transfer body 11 with a pressure that does not hinder the rotation of the intermediate transfer body 11. Take-up roller 2
The cleaning roller 222 is rotated by rotating the cleaning roller 222.
The cleaning member 224 stretched around the reel is wound up from the felt roller 221 and rotated at a required rotation speed.
The ink remaining on the surface of the intermediate transfer body 11 is wiped off by the cleaning member 224. The take-up roller 223 may be intermittently rotated at a required interval by a required size.

Next, the operation will be described. While rotating the intermediate transfer member 11 at a predetermined speed in the direction of the arrow in FIG.
By ejecting ink droplets from the recording head 12, an ink image is formed on the surface of the intermediate transfer body 11.

Then, in synchronism with the formation of the ink image, the recording paper secondarily fed by the registration roller pair 17 is sandwiched between the intermediate transfer body 11 and the pressure roller 21 and conveyed, and the intermediate pressure is applied by the applied pressure. The ink image on the transfer body 11 is transferred to the recording paper, and the ink remaining on the intermediate transfer body 11 after the transfer is removed by the cleaning device 22.

In this way, since the outer periphery of the intermediate transfer body 11 is formed of the foam layer 111 and the annular protrusion 112 is formed on the surface, ink droplets ejected in contact with each other on the intermediate transfer body 11. It is possible to maintain the separated state without the coalescing of 121, and thereby a high quality printed image can be obtained when transferred to the recording paper. Further, the foam layer 11 is made of silicone rubber, fluororubber or the like having a good releasing property.
Since No. 1 is formed, the ink image can be appropriately transferred to the recording paper, and the residual ink can be reduced.

FIG. 2 is a front view showing a main part of the second embodiment of the ink jet recording apparatus according to the present invention. In addition,
The same members as those in the first embodiment are designated by the same reference numerals. In the second embodiment, the intermediate transfer member 1 is applied to the front and back surfaces of the transport paper.
1, the recording head 12 and the cleaning device 22 are arranged symmetrically.

The peripheral surfaces of the intermediate transfer members 11 and 11 are pressed against each other with a required pressure, and the recording sheet sandwiched between the intermediate transfer members 11 and 11 is conveyed while the intermediate transfer member 11 is being conveyed. The ink images formed on the surfaces of 11 and 11 are transferred to both surfaces thereof by the applied pressure.

Thus, in the second embodiment, it is possible to print on both sides of the recording paper at the same time. Also,
The intermediate transfer members 11 and 11 can also function as pressure rollers, and there is no need to provide a separate pressure roller.

In each of the above-mentioned embodiments, the intermediate transfer member 11 is not limited to the drum shape, and may be an endless belt shape.

The protrusions formed on the surface of the foam layer 111 are not limited to annular ones. For example, a large number of needle-like or spherical protrusions are formed side by side, and irregularities are formed between the protrusions and the protrusions. It may be one that has been adapted.

[0037]

As described above, according to the first aspect of the present invention, since the minute protrusions are formed on the surface of the intermediate transfer member, the adjacent ink droplets can be kept separated without being combined. It is possible to obtain a high quality printed image.

Further, according to the second aspect of the invention, since the protrusion is formed in an annular shape having a diameter equal to or smaller than that of the ink droplet, the ink droplet ejected onto the intermediate transfer member is different from the protrusion formed on the surface. Since the ink droplets come into contact with each other at a plurality of points, adjacent ink droplets can be reliably held in a separated state without coalescing due to the frictional force, whereby a high-quality printed image can be obtained.

Further, according to the inventions of claims 3 and 4, since the surface of the intermediate transfer member is a silicone rubber or a fluororubber foamed by adding a foaming agent, the amount of the foaming agent to be added and the foaming conditions. Thus, the diameter of the protrusion can be formed to be equal to or smaller than the ink droplet. Further, by using a silicone rubber or fluororubber having a good releasability, the ink image formed on the intermediate transfer member can be suitably transferred to a recording sheet, and a high quality printed image can be obtained.

[Brief description of the drawings]

FIG. 1A is a front view showing an internal configuration of a first embodiment of an inkjet recording apparatus according to the present invention, and FIG. 1B is a view showing a state of ink droplets ejected onto an intermediate transfer member.

FIG. 2 is a front view showing a main part of a second embodiment of an inkjet recording apparatus according to the present invention.

FIG. 3 is a diagram showing a state of ink droplets ejected onto an intermediate transfer member having a smooth surface.

[Explanation of symbols]

 11 Intermediate Transfer Body 111 Foam Layer 112 Annular Protrusion 12 Recording Head 121 Ink Drop 21 Pressure Roller

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Koichi Baba 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Industrial Co., Ltd. (72) Yoshiko Uryu 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Within Kogyo Co., Ltd. (72) Inventor Setsuo Hori 1-22 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd.

Claims (4)

[Claims] 1. An ink droplet is ejected from a nozzle of a recording head toward the surface of an intermediate transfer member, and is adhered to the surface of the intermediate transfer member to form an ink image, and the ink image is transferred to a recording medium. A transfer-type inkjet recording device for performing printing, wherein the intermediate transfer member has minute protrusions formed on the surface thereof. 2. The transfer type inkjet recording apparatus according to claim 1, wherein the protrusion is formed in an annular shape having a diameter equal to or smaller than the ink droplet. 3. The transfer type ink jet recording apparatus according to claim 2, wherein the surface of the intermediate transfer member is a silicone rubber foamed by adding a foaming agent. 4. The transfer type ink jet recording apparatus according to claim 2, wherein the surface of the intermediate transfer member is a fluororubber foamed by adding a foaming agent.