JPH01316273A - Printing member cleaning method and printing apparatus - Google Patents

Abstract

PURPOSE:To clean a member easily in a short time and to facilitate the automatization of the cleaning method by applying a printing ink varying in adhesion by electrical conduction to an absorbing material containing a component common to that of the ink to remove the ink off from the surface of the member. CONSTITUTION:In the condition that a cleaning roll 15 is not in contact with a second intermediate roll 7, the same ink as a printing ink is supplied between the both rolls to form a cleaning adsorbing material layer 17 on the second cleaning roll 15. Next, the second intermediate roll 7 is separated from a plate roll 9, and the cleaning adsorbing material layer 17 is brought into contact with the surface of the second intermediate roll 7. Thereafter, in the condition that the plate roll 9 is not in contact with the second intermediate roll 7, the polarity of the voltage of a first intermediate roll 5 is made reverse to that of an ink holding roll 1; the first intermediate roll 5, the second intermediate roll 7, and the ink holding roll 1 are rotated, and the printing ink remaining on the second intermediate roll 7 is applied and transferred to the adsorbing material layer 17. Simultaneously, the printing ink on the first intermediate roll 5 is applied to an ink layer 2 on the ink holding roll 1.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a method for cleaning a printing member in printing using printing ink whose tackiness changes when energized, and a cleaning method for carrying out the method. The present invention relates to a printing device having a cleaning means.

[Conventional technology]

In recent years, printing inks whose tackiness changes when energized have been proposed (Japanese Unexamined Patent Publications No. 63-10279, JP-A No. 63-71386, etc.).

If such ink is used, it is possible to adjust the ink transfer mound using a relatively smaller number of rollers than in conventional offset printing, etc., making maintenance easier and making it possible to make the printing device more compact.

[Problem to be solved by the invention]

Normally, when printing, for example at the end of printing or when changing ink, it is necessary to remove the printing ink remaining on the printing roll, in other words, cleaning the printing roll. be.

Conventionally, in printing using printing ink whose tackiness changes when electricity is applied, an operator cleans the surface of the printing roll using a cloth or paper moistened with an appropriate solvent. This was done by wiping it off.

However, such cleaning methods have the problem that the ink cannot be easily removed, the work is time consuming, and the work is complicated, so the ink or solvent may adhere to unnecessary areas. Ta.

An object of the present invention is to provide a method for cleaning a printing member that can be easily and effectively carried out in a short period of time in printing using printing ink whose tackiness changes when energized, and a cleaning method for carrying out the method. An object of the present invention is to provide a printing device having a means.

[Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted intensive research and found that 1. A printing ink whose viscosity changes when energized has a composition similar to that of the printing ink. The present inventors have discovered the property that they easily adhere to other compounds, and have completed the present invention.

Hereinafter, the cleaning method of the present invention will be explained in detail.

The cleaning method of the present invention is a method for cleaning a printing member to which printing ink (hereinafter simply referred to as "printing ink") whose tackiness changes when energized is attached to the printing member. It is characterized by including the step of attaching the printing ink to an adsorbent (hereinafter referred to as "cleaning adsorbent") containing the same constituent material as the printing ink and removing it from the member. .

In the method of the present invention, since cleaning is performed using a "cleaning adsorbent" that has excellent adhesion to "printing ink," the printing member can be cleaned easily and in a short time. Moreover, the cleaning method is easy to automate.

Note that when performing the cleaning method of the present invention, the lower the adhesiveness of the printing ink to the member, the easier it is to remove.

Therefore, for example, if the "printing ink" to be cleaned is an ink that becomes more sticky when energized, it is preferable to perform cleaning without energizing. Furthermore, if the "printing ink" to be cleaned is an ink whose adhesiveness decreases when energized, it is preferable to perform cleaning while energized.

According to the method of the present invention, various printing rolls such as printing intermediate rolls, printing plate rolls, plan rolls, ink carrying rolls, coating rolls, and ink in various printing devices such as ink supply channels can be used. The member (printing member) constituting the part that comes into contact with can be cleaned well.

The "cleaning adsorbent" used in the method of the present invention will be described in detail below.

The "cleaning adsorbent" used in the method of the present invention is
This is a composition that includes the same constituent materials as printing ink whose tackiness changes when electricity is applied, that is, a composition that includes a liquid dispersion medium and a polymer that holds the liquid dispersion medium.

Desirable types and composition ratios of the polymer and liquid dispersion medium contained in the "cleaning adsorbent" vary depending on the type of "printing ink" to be cleaned. especially,
It is desirable to contain polymers and liquid dispersion media similar to those constituting the "printing ink" to be cleaned in a similar composition ratio; Furthermore, it is preferable to contain the ink at a certain ratio from the viewpoint of reusing the ink.

In addition, it is important to use cleaning adsorbents that have the same polymer and liquid dispersion medium as well as other components (colorants, additives, etc.), that is, cleaning adsorbents and printing adsorbents. The "printing ink" and "cleaning adsorbent" obtained after cleaning according to the present invention have the same composition.
This is very preferable because the mixture can be reused as is as a printing ink.

Examples of the polymer contained in the "cleaning adsorbent" include crosslinked substances and polymer electrolytes.

The term "crosslinked substance" here refers to a substance that can form a crosslinked structure by itself, or a substance that forms a crosslinked structure by adding other additives (for example, a crosslinking agent made of inorganic ions such as borate ions). A substance that makes it possible to

Furthermore, the term "crosslinked structure" refers to a three-dimensional structure having "crosslinked bonds."

In the "cleaning adsorbent" used in the present invention, this "crosslinking bond" can be any of ionic bonds, hydrogen bonds, or van der Waals bonds (or two of these bonds).
(a combination of more than one species).

In the [cleaning adsorbent] used in the present invention,
The above-mentioned "crosslinked structure" is sufficient as long as it can obtain the desired liquid dispersion medium retention property. That is, this crosslinked structure may be, for example, a net, honeycomb, or spiral structure, and may not be a regular structure.

In the [cleaning adsorbent] used in the present invention,
As the liquid dispersion medium, various inorganic or organic solvents that are liquid at room temperature can be used, but solvents with relatively low volatility (e.g., equivalent to or lower than water) may be used. It is preferable to use

When a hydrophilic dispersion medium such as water or a water-containing dispersion medium is used as the liquid dispersion medium, a hydrophilic (natural or synthetic) polymer or the like is preferably used as the crosslinked structure substance.

Examples of such hydrophilic polymers include guar gum,
Plant-based polymers such as locust bean gum, gum arabic, taragant, carrageenan, pectin, mannan, and starch; Microbial polymers such as xanthan gum, dextrin, succinoglucan, and curdlan; Animal-based polymers such as gelatin, casein, albumin, and collagen. Cellulose polymers such as methyl cellulose, ethyl cellulose, and hydroxyethyl cellulose; or starch polymers such as soluble starch, carboxymethyl starch, and methyl starch Alginic acid polymers such as propylene glycol nialginate and alginate: Other polysaccharides Semi-synthetic polymers such as derivatives of polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl methyl ether, carboxyvinyl polymer, polyacrylamide, sodium polyacrylate, etc.Other polyethylene glycol, ethylene oxide, propylene oxide block copolymer Synthetic polymers such as synthetic polymers; etc. are preferably used alone or in combination of two or more as necessary.

These hydrophilic polymers are generally preferably used in an amount of 0.2 to 50 parts by weight, particularly preferably 0.5 to 30 parts by weight, per 100 parts by weight of the liquid dispersion medium.

Another form of "cleaning adsorbent" that includes a polymer electrolyte is one that includes a polymer electrolyte that is a polymer having a dissociative group in its polymer chain. Examples of substances that dissociate and produce polymer ions when dissolved in water include natural polymers such as alginic acid and gelatin; and those synthesized by introducing dissociative groups into synthetic polymers such as polystyrene sulfonic acid and polyacrylic acid. .

On the other hand, when using a dispersion medium made of oil such as mineral oil or an organic solvent such as toluene as the liquid dispersion medium,
For example, metal soaps of stearic acid such as aluminum stearate, magnesium stearate, and zinc stearate; other metal soaps made of similar metal salts of fatty acids such as palmitic acid, myristic acid, and lauric acid; or hydroxypropyl cellulose derivatives; Dihencylidene D
-Organic substances such as sorbitol, sucrose fatty acid ester, dextrin fatty acid ester, etc. (similar to the above-mentioned hydrophilic polymers) are preferably used alone or in combination of two or more as necessary.

The "cleaning adsorbent" that can be used in the method of the present invention has the above-mentioned liquid dispersion medium and a crosslinked structure substance or a polymer electrolyte as essential components. Moreover, a coloring agent and other additives may be included as necessary.

In order to obtain a "cleaning adsorbent" consisting of the above-mentioned components, for example, a liquid dispersion medium such as water, a crosslinked structure substance consisting of a hydrophilic polymer, etc. (if necessary, a crosslinking agent, a coloring agent, an electrolyte, etc.) are required. etc.) and/or a polymer electrolyte are uniformly mixed while heating to form a viscous solution or dispersion, and then cooled to gel.

Next, the printing apparatus of the present invention will be explained in detail.

The printing apparatus of the present invention includes an electric energy application means for applying electricity to the printing ink to change the tackiness of the printing ink, and the printing apparatus includes an adsorbent containing a common constituent material with the printing ink. The apparatus is characterized in that it has a cleaning means for carrying the printing ink, which is attached to the member, to adhere to the adsorbent and removing it from the member.

More specifically, the printing device of the present invention is a device that is capable of printing using printing ink whose tackiness changes when energized, and is equipped with a means for carrying out the above-described cleaning method of the present invention. be.

The shape and material of the cleaning means in the printing apparatus of the present invention are not particularly limited.

The shape may be any shape as long as it can sufficiently support the absorbent material, and may be various shapes such as a roller, a flat plate, and a spherical shape. In addition, the surface material is preferably one that can sufficiently support the absorbent material, that is, one that has excellent adhesion to the absorbent material, and is preferably made of stainless steel, chromium, platinum, etc. . Also,
If necessary, a coating roll or the like may be used to make the layer thickness of the absorbent material carried on the surface of a roller or the like uniform. The preferred layer thickness of the absorbent material supported on the surface of the cleaning means varies depending on the amount of printing ink to be cleaned, etc., but it is equal to or thicker than the layer thickness of the printing ink to be cleaned. It is preferable.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the printing apparatus of the present invention.

The "means for applying electrical energy to printing ink" in this apparatus is a DC power supply that is electrically connected to the ink carrying roll 1 and the first intermediate roll 5.

By controlling the voltage applied between these rolls,
Since the tackiness of the printing ink on the ink carrying roll 1 can be controlled, the amount of printing ink transferred from the ink carrying roll 1 to the first intermediate roll 5 can be controlled, and the transfer amount of the printing ink from the first intermediate roll 5 to the second intermediate roll can be controlled. The amount of printing ink transferred to 7 can be controlled.

The cleaning means in this device is a cleaning roll 15 carrying a cleaning adsorbent layer 17 on its surface. Further, as an auxiliary means to the cleaning means, a coating roll 16 that can control the layer thickness of the adsorbent layer 17 is also provided. The second intermediate roll 7 can be cleaned by this cleaning means.

Moreover, if the position of this cleaning means can be moved freely, the ink carrying roll 1, the coating roll 4, the first intermediate roll 51, the plate roll 9, the plan roll 11, etc. It is also possible to clean the pressure roll 13.

In addition, in this apparatus, when cleaning the first intermediate roll 5, the cleaning method of the present invention can be performed without using the cleaning roll 15. That is, if the first intermediate roll 5 and the ink carrying roll l are rotated while being in contact with each other in a state where no current is applied and the ink layer 3 on the ink carrying roll 1 is appropriately thick, the first intermediate roll 5 and the ink carrying roll l are rotated. - The printing ink remaining on the intermediate roll 5 adheres to the ink layer 3 and is removed, and the first intermediate roll 5 is cleaned.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 <Preparation of ink> Inks used as "printing ink" and "releaning adsorbent" in this example were prepared as follows.

First, a solution was prepared by uniformly mixing the following components while heating them to 80 to 90°C.

・Propylene glycol 80 parts by weight water
20 parts by weight, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd. Potassium iodide 14 parts by weight, carbon black IO parts by weight Product name Nistarring SR Manufactured by Cabot, USA Next, the following components were added to the solution and stirred to form a gel. An ink was prepared.

・I N-NaOH 3.3 cc ・20 wt% sodium borate monopropylene glycol solution 3.3 cc Printing> Using the ink prepared as above, printing was performed as follows using the printing apparatus shown in Figure 1. I did it.

First, the ink is supplied as the ink reservoir 3, the ink carrying roll 1 is rotated in the direction A, and the coating roll 4 is rotated.
was rotated in direction B.

As the ink carrying roll 1, a stainless steel cylindrical roll (surface roughness is) of 30 fflIllφ was used, and the rotation speed in the inlet direction was 201111/sec.

Further, the coating roll 4 was a cylindrical roll made of Teflon rubber with a surface of 30 weφ, and its rotational speed in the B direction was 2011 Im/sec.

Next, the gap between the ink carrying roll 1 and the coating roll 4 was controlled so that the thickness of the ink layer 2 on the surface of the ink carrying roll 1 was 1.2 mm.

Next, the first intermediate roll 5 is an ink carrying roll! It was rotated in the C direction while being brought into contact with the ink layer 2 above. At that time, in a state where no voltage was applied between the first intermediate roll 5 and the ink carrying roll 1, the ink layer 2 was not transferred to the first intermediate roll 5 side.

As the first intermediate roll 5, a platinum-plated stainless steel cylindrical roll with a diameter of 30 mm was used, and the rotation speed in the C direction was 20 mm and 1 second.

Next, when a voltage of 25V was applied through the ink layer 2 using the first intermediate roll 5 as an anode and the ink carrying roll 1 as a cathode, the tackiness of the surface of the ink layer 2 (first intermediate roll side) decreased. It is transferred onto the surface of the first intermediate roll 5 to a thickness of 0. A first ink thin film 6 having a thickness of Ia++w or less was formed.

Next, when the second intermediate roll 7 was rotated in the D direction while contacting the first ink thin film 6 on the first intermediate roll 5, the first ink thin film 6 was transferred to the surface of the second intermediate roll 7. A second ink thin film 8 having a thickness of 0.1 mm or less was formed.

The second intermediate roll 7 is a stainless steel cylindrical roll with a diameter of 30 mm whose surface is coated with silicone rubber, and its rotational speed in the D direction is 20 m5/
Seconds.

Next, when the printing plate IO on which the toner image was formed was rotated in the E direction while the plate roll 9 existing on its surface was brought into contact with the second ink thin film 8 on the second intermediate roll 7, the second ink ? 'll Ili 8 was transferred only to the area on the printing plate 10 where the toner image was formed.

The printing plate 10 on which the toner image is formed is produced by coating a fluorine-based polymer paint (manufactured by Sumitomo 3M, FC-721) on a polyimide film to form a water-repellent coating film with a thickness of approximately 1 μm. Then, an electrophotographic toner mainly composed of polyamide resin was transferred and fixed thereon using an electrophotographic dry copying machine (Canon, PC-12) to form a toner image. The printing plate 10 produced in this way is wound around the plate roll 9,
This was used in the apparatus shown in FIG.

Next, when the plan roll 12 having the blanket 11 on its surface was rotated in the F direction while contacting the printing plate 1θ onto which the ink was imagewise transferred, the imagewise ink on the printing plate IO was transferred to the blanket. transferred to the surface of I+.

In addition, urethane rubber was used for the blanket H. Moreover, a roll of 100 mmφ was used as the plan roll 12, and its rotational speed in the F direction was set to 20 mm/sec.

Next, while bringing the pressure roll 13 into pressure contact with the plan roll 12 via the recording medium 14, the plan roll 12 is moved in the G direction.
When the ink image was rotated at the same speed as the recording medium 14, an ink image was successfully transferred onto the recording medium 14.

The pressure roll 13 is a 40fflIIIφ roll whose surface is covered with silicone rubber, and the pressure is 3.
It was set to 0 kg/cm2. Furthermore, plain paper was used as the recording medium 14.

The above printing was performed continuously on 100 sheets of plain paper. There were no major image disturbances in the images printed on the 100 sheets of plain paper.

<Cleaning> In the printing apparatus that printed as described above, printing ink remained on the first intermediate roll 5, the second intermediate roll 7, and the plan roll 11. Therefore, each roll was cleaned as follows.

First, while the cleaning roll 15 and the second intermediate roll 8 are not in contact with each other, the second cleaning roll 15 is rotated in the H direction, and the second coating roll 16 is rotated! The same ink as the printing ink was supplied between the rollers while rotating in the direction of the roller, thereby forming a cleaning adsorbent layer 17 on the second cleaning roll 15.

As the second cleaning roll 15, a cylindrical roll with a diameter of 30 mm and a stainless steel surface was used, and the rotation speed in the H direction was 20 mm/sec. Further, as the second coating roll 16, a cylindrical roll having a diameter of 30 mm and made of Teflon rubber was used, and the rotation speed in the direction (2) was set to 20 III/sec.

Next, the thickness of the cleaning absorbent layer 17 was 1.2 m.
The gap between the second cleaning roll 15 and the second coating roll 16 was controlled so that it became i+.

Next, the contact between the second intermediate roll 7 and the plate roll 9 was removed, and the surface of the cleaning adsorbent layer 17 was brought into contact with the surface of the second intermediate roll 7.

Next, in a state where the plate roll IO and the second intermediate roll were not in contact with each other, the polarity of the voltage between the first intermediate roll 5 and the ink carrying roll 1 was reversed and 5V was applied, but in the same manner as in printing, The first intermediate roll 5, the second intermediate roll 7, and the ink carrying roll 1 were rotated.

Then, the printing ink remaining on the second intermediate roll 7 was attached and transferred to the cleaning adsorbent mI7 on the second cleaning roll 15. At the same time, the printing ink remaining on the first intermediate roll 5 adhered to the ink layer 2 on the ink carrying roll 1.

When the leaning was performed for one minute as described above, the printing ink remaining on the second intermediate roll 7 and the first intermediate roll 5 was completely removed.

Next, while the plan roll 11 and the plate roll 9 are not in contact with each other, the blank cleaning roll 18 is rotated in the J direction, and while the plan coating roll 19 is rotated in the direction, the same ink as the printing ink is applied to the roller. A blank cleaning adsorption member layer 20 was formed on the blank cleaning roll I8.

The same blank cleaning roll 18 as the second cleaning roll 15 was used, and its rotational speed in the J direction was 20 mm/sec. Also, the blank cleaning roll 19 is a coating roll! 6 was used, and the rotational speed in the direction was 2θIIL/sec.

Next, the thickness of the plan cleaning absorbent layer 20 is 1
．． The gap between the blank cleaning roll 18 and plan coating roll 19 was controlled to be 2 mm. Next, the blanket 12 and the plan cleaning adsorbent layer 20 are brought into contact with each other, and the plan roll 11, the blank cleaning roll 18, and the plan coating roll 19 are brought into contact with each other.
When both were rotated for 1 minute at a speed of 20 ffil/sec, all of the ink on the plan roll 11 was absorbed by the plan cleaning adsorbent layer 2°.

〔Effect of the invention〕

As explained below, according to the cleaning method of the present invention, printing members can be cleaned easily and effectively in a short time.

Further, since the apparatus of the present invention has a cleaning means capable of carrying out the cleaning method of the present invention, it is an apparatus that can easily and effectively clean a printing member in a short time.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing one embodiment of the printing apparatus of the present invention. 1... Ink carrying roll 2... Ink layer 3...
Ink reservoir 4...Coating roll 5.
...First intermediate roll 6...First ink thin layer 7...
-Second intermediate roll 8...Second ink thin layer 9...
Plate roll 10... Ink reservoir 11... Plan roll 12... Blanket 13... Pressure roll 14... Recorded object 15... Second cleaning roll 1... Second coating roll 17... ...Adsorbent layer for cleaning 18...Blank cleaning roll 19...Plan coating roll 20...Adsorbent layer for plan cleaning Patent applicant
Canon Co., Ltd.

Claims (2)

[Claims] (1) A method for cleaning a printing member to which a printing ink whose tackiness changes when energized is applied, wherein the printing ink present on the member contains a common constituent material with the printing ink. A method for cleaning a printing member, comprising the steps of adhering it to an adsorbent and removing it from the member. (2) In a printing device having an electric energy applying means for applying electricity to printing ink to change the tackiness of the printing ink, a member supporting an adsorbent containing a constituent material common to the printing ink; A printing apparatus characterized by comprising a cleaning means for causing the printing ink adhering thereon to adhere to the adsorbent and removing it from the member.