JPH08276565A - Print image post-processing device - Google Patents

Abstract

(57) [Abstract] [Purpose] The printed material P that has been printed is conveyed by the contact roller 37 and the counter roller 39 to which the excess ink removing liquid has been applied, and the excess ink is transferred to the contact roller to transfer the excess ink. In an apparatus that removes excess printing ink from an image, excess ink removing liquid mixed with excess ink is separated and reused. [Structure] Excess ink removing liquid that is incompatible with printing ink and whose surface tension is lower than that of printing ink
Applied to 37. The surplus ink removing liquid of the contact roller 37 comes into contact with the printed image surface of the printing medium. Surplus of printing ink c
Is transferred from the material P to be printed to the excess ink removing liquid of the contact roller 37, and is removed from the contact roller 37 by the blade 45 as the contact roller 37 rotates. The excess ink removing liquid mixed with the printing ink is centrifugally separated by the rotating filter, and only the excess ink removing liquid is supplied to the contact roller 37 again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print image post-processing apparatus used in a printing apparatus such as stencil printing. The present invention is particularly effective as a countermeasure against set-off and strike-through in printed matter.

[0002]

2. Description of the Related Art In printing using a liquid printing ink, when printing materials are overlaid immediately after printing, the printing ink forming a printed image adheres to the back surface of one sheet, causing set-off. Also, immediately after printing, the printed image surface may be rubbed lightly with your fingertips, which may cause the printed image to collapse, or the printing ink that forms the printed image may pass through the substrate. Problems such as see-through on the back surface may occur.

These problems are particularly noticeable in stencil printing, in which the amount of printing ink forming a printed image on a printing medium, that is, the amount of ink buildup is larger than that of other printing.

[0004] Conventionally, in order to prevent the occurrence of such set-off and strike-through, attempts have been made to reduce the amount of inking on the printing medium during the printing process. However, it is difficult to quantitatively control the amount of buildup, and if the amount of buildup is suppressed too much, the density of the printed image will be reduced, the print will be blurred, and the quality of the printed image will be degraded.

As a means for avoiding the above-mentioned problems, it is conceivable to heat and dry the printing ink for forming a printed image, but in that case, a heater having a considerably large calorific value must be used. . In this way, when the printing material is dried by the drying means such as a heater, the higher the printing speed of the printing press, the more severe the conditions imposed on the drying means. Actually, the printing ink cannot be dried at such a high speed that an effect of preventing the occurrence of set-off and strike-through can be obtained.

In addition, depending on the printing method, fine powder such as starch or talc may be applied to the printed image surface to prevent set-off. However, such a fine powder coating device uses compressed air, and a printing device equipped with such a device becomes a considerably large printing device.

Further, the printing target after the printing is completed is a paper discharge tray,
When transporting to a sorter, etc.
The conveyance roller cannot be applied to the printed image surface of the printing medium. For this reason, conventionally, the printing medium has been transported by a transportation mechanism such as a belt conveyor that contacts only the back surface (non-printing image surface) of the printing medium. This type of printing medium conveying device is disclosed in, for example, Japanese Patent Application Laid-Open No. 50-88769.

However, if the printed material is conveyed by contacting only the back surface without contacting the printed image surface, when the copying paper is forcibly conveyed while being sandwiched from both sides like a copying machine such as a PPC. In comparison, the paper ejection performance is inferior, such as the occurrence of paper misalignment at the delivery destination such as the paper ejection tray or the sorter. This tendency has become remarkable as the printing speed, in other words, the paper discharge speed is increased. Further, such a problem greatly reduces the degree of freedom in setting the route of the sheet discharge conveyance path in the printing apparatus.

[0009]

The present inventors have invented a novel apparatus for removing excess ink from a printing medium in order to improve printing quality. This apparatus has a contact roller that rotates by applying a surplus ink removing liquid in a layered manner on the peripheral surface, and a counter roller that rotates in opposition to the contact roller,
The printed material is sandwiched and conveyed by the contact roller and the facing roller. Then, the excess printing ink on the printed image surface of the printing medium is transferred to the layered excess ink removing liquid of the contact roller, and the excess ink on the contact roller is a cleaning means such as a blade that contacts the contact roller. Remove by.

The excess ink removing liquid used in the above apparatus is a liquid that is incompatible with the printing ink and has a lower surface tension than the printing ink. Therefore, when the surplus ink is transferred from the printed matter to the contact roller coated with the surplus ink removing liquid, the surplus printing ink exists in a state of being dispersed in the surplus ink removing liquid. In order to reuse the excess ink removing liquid, it was necessary to separate the excess ink removing liquid and the printing ink.

The present invention aims to improve the above-mentioned apparatus for removing excess ink, which has been proposed by the inventors of the present application, by paying attention to the conventional problems as described above. It is possible to reliably avoid the occurrence of set-off and strike-through without inducing other obstacles, remove the excess printing ink on the printed image surface, and use the excess ink used to remove the excess printing ink. It is an object of the present invention to provide a printed image post-processing device that can repeatedly use a removing liquid.

[0012]

According to a first aspect of the present invention, there is provided a printed image post-treatment device, which is applied with an excess ink removing liquid which is incompatible with the printing ink for forming a printed image and has a lower surface tension than the printing ink. Of the surplus printing ink among the printing ink forming the printed image of the printed material by transporting the printed material to be sandwiched between the contact member that is driven to rotate and the contact member. A facing member that transfers to the surplus ink removing liquid, a supply unit that supplies the surplus ink removing liquid to the contact member, and a surplus printing ink that is rotationally driven around its own central axis and is supplied in the vicinity of the central axis. It is characterized by comprising a separating means for separating the excess ink removing liquid containing the ink into the excess ink removing liquid and the printing ink by passing the excess ink removing liquid by the centrifugal force during the rotation drive.

According to a second aspect of the present invention, there is provided a printed image post-processing apparatus according to the first aspect, wherein the separating means has a porous material through which only the excess ink removing liquid can pass. It is characterized by

The print image post-processing apparatus according to a third aspect is the print image post-processing apparatus according to the second aspect, wherein the excess ink removing liquid separated by the separating means is supplied to the contact member again for use. It is characterized by doing.

[0015]

The surplus ink removing liquid adhering to the peripheral surface of the contact member comes into contact with the printed image surface of the printing medium. The surplus of the printing ink forming the printed image is transferred to the surplus ink removing liquid of the contact member and is removed from the printing medium. The excess ink remover is incompatible with the printing ink that forms the printed image,
The surface tension of the liquid is lower than that of the printing ink.
For this reason, the surplus printing ink transferred to the surplus ink removing liquid exists on the surface of the surplus ink removing liquid in a floating state that is physically separated from the surplus ink removing liquid. The surplus printing ink floating from the surface of the contact member is removed from the contact member together with the surplus ink removing liquid by the cleaning unit that contacts the surface of the contact member as the contact member rotates. The separating means composed of a porous material that allows only the excess ink removing liquid to pass is rotated around its own central axis, and the excess ink removing liquid containing the printing ink is supplied in the vicinity of the central axis, and centrifugal force and separating means are applied. Since the separation is performed by the action of, the excess ink removing liquid and the printing ink can be efficiently separated. The excess ink removing liquid obtained by separation can be supplied to the contact member again and used for removing the excess ink.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the stencil printing machine of the first embodiment will be described with reference to FIGS. The document image reading unit 5 has an image scanner 3 and reads an image of a document to be printed. The plate making unit 9 has a plate making device 7 and forms a punched image on the stencil printing base paper S in accordance with the document image data read by the document reading unit 5.

On the outer peripheral surface of the cylindrical printing drum 13, the stencil printing base paper S punched by the plate making section 9 is wound. An ink supply device 11 including an ink squeegee device is provided inside the print drum 13, and supplies ink to the inner peripheral surface of the print drum 13. Below the printing drum 13 is a press roller 15 that moves up and down. Press roller 15
Is configured to nip and convey the printing medium P supplied between the printing drum 13 and the press roller 15 between the printing drum 13 and form an image on the printing medium P.

In the paper feeding section 23, the printing medium P on the paper feeding table 17 is fed one by one by the paper separating roller 19, and the press roller 1 is fed by the paper feeding timing roller 21.
5 and the printing drum 13.

In the paper output section 33, the stripping claw 25 strips the material to be printed from the printing drum 13. The stripped printing material P is transported to the print image post-processing device 29 by the transport device 27 of the belt conveyor mechanism. The print image post-processing device 29 performs a process of removing excess ink from the print image of the printing medium P. The processed printing substrate is the paper output table 31.
It is discharged to and piled up.

The stencil printing base paper S for which printing has been completed is peeled off from the printing drum 13 by the plate discharge section 35 and discarded.

The printing operation in the above configuration will be described.
The printing drum 13 is rotationally driven in the counterclockwise direction in the figure around its own central axis by a driving unit (not shown). The printing medium P is conveyed from the left side to the right side in the figure by the paper feed timing roller 21 at a predetermined timing synchronized with the rotation of the printing drum 13, and is supplied between the printing drum 13 and the press roller 15. The printing medium P is pressed by the press roller 15 against the stencil sheet S wound around the outer peripheral surface of the printing drum 13, and stencil printing is performed.

The printed substrate P has a peeling claw 25.
Is peeled off from the print drum 13 and is sent to the print image post-processing device 29 by the paper discharge conveying device 27 with the print image surface facing upward. The printing medium P is the print image post-processing device 2
The sheet 9 is conveyed toward the sheet discharge tray 31 while being subjected to the post-processing operation of the print image, and is stacked on the sheet discharge tray 31.

Next, the structure and operation of the print image post-processing device 29 will be described. As shown in FIG. 2, the print image post-processing device 29 includes a contact roller 37 as a contact member that contacts the print image surface (upper surface) of the printing target P after printing is completed.
And a counter roller 39 as a counter member that is arranged to face the contact roller 37. The contact roller 37 and the counter roller 39 are rotatably supported in parallel with each other by shafts 41 and 43, respectively. The opposing roller 39 is urged upward in the figure, that is, toward the contact roller 37 by a spring as an urging means (not shown). When there is no printing target P between the contact roller 37 and the counter roller 39, the contact roller 37 and the counter roller 39 contact each other.

A blade 45, which is a plate-shaped member having a substantially rectangular cross section, is in contact with the outer peripheral surface 37a (surplus ink removing liquid application surface) of the contact roller 37. The blade 45 has a base end fixed to the tip of the sheet metal member, and the tip is in contact with the contact roller 37. The blade 45 is provided in a posture inclining above the apex of the contact roller 37, and the lower corner of the tip of the blade 45 is on the outer peripheral surface of the contact roller 37 on the rotation front side of the apex of the contact roller 37. It is in contact with 37a.

A surplus ink removing liquid supply nozzle 47 is provided above the outer peripheral surface 37a of the contact roller 37 on the front side in the rotation direction from the contact position between the blade 45 and the contact roller 37.
Is provided. Excess ink removal liquid supply nozzle 47
Is for removing the excess ink removing liquid from the outer peripheral surface 3 of the contact roller 37.
It is a supply means for supplying to 7a. Excess ink remover is
It is a liquid that is incompatible with the printing ink forming the printed image and has a surface tension lower than that of the printing ink.

When the excess ink removing liquid supply nozzle 47 supplies the excess ink removing liquid to the outer peripheral surface 37a of the contact roller 37, the excess ink removing liquid accumulates between the blade 45 and the contact roller 37 as shown in the drawing. . Contact roller 37
With the rotation of, the excess ink removing liquid passes between the contact roller 37 and the blade 45 to form a layer on the surface of the contact roller 37. At this time, the blade 45 has a function of making the amount of the excess ink removing liquid formed on the outer peripheral surface 37a of the contact roller 37 uniform. Further, the blade 45 also functions as a cleaning unit that removes dirt on the outer peripheral surface 37a of the contact roller 37.

A sheet-like elastic body 49 is provided on the front side of the blade 45 in the rotating direction of the contact roller 37 as a means for collecting the excess ink removing liquid. The sheet-shaped elastic body 49 is a thin plate-shaped member having a predetermined elasticity. At the contact point d located on the front side in the rotation direction of the contact roller 37 with respect to the contact position between the blade 45 and the contact roller 37,
The tip of the sheet-like elastic body 49 is in contact with the outer peripheral surface 37 a of the contact roller 37. Further, the sheet-shaped elastic body 49
Is arranged at a position closer to the contact roller 37 than the tangent line e of the contact roller 37 at the contact point d, and the rear end thereof is lower than the front end. Therefore, a part of the sheet-like elastic body 49 near the tip end portion is brought into close contact with the outer peripheral surface 37a of the contact roller 37 with a predetermined length.
It is elastically deformed following the shape of a.

The rear end portion of the sheet-like elastic body 49 is fixed to the tray member 51 for the excess ink removing liquid, which is arranged below the contact point d. The leading end of the sheet-like elastic body 49 is a free end and is in contact with the contact roller 37 as described above. In this way, the sheet-like elastic body 49 is arranged so that the free end of the elastic body 49 contacts the contact roller 37 and the fixed rear end of the elastic body 49 is positioned downward.

A discharge pipe 51a for discharging the excess ink removing liquid containing excess ink is connected to the lower surface of the tray member 51. The discharge pipe 51a is guided to the separating means 60. The separating means 60 is a substantially cylindrical filter 55 for separating the printing ink and the excess ink removing liquid, and the filter 5
5, and a substantially cylindrical recovery container 57 that stores the excess ink removing liquid separated by the filter 55.
And a driving means (not shown) for driving the filter 55 to rotate around its own central axis inside the recovery container 57. A hole 55a is formed in the center of the filter 55 along the central axis thereof, and the lower end of the discharge pipe 51a is arranged inside the hole 55a. Collection container 5
A pipe 58 is connected and communicated with the lower surface of 7, and the pipe 58 is connected to the surplus ink removing liquid supply nozzle 47 via a pump 59 which is a liquid conveying means.

At least a part of the constituent material of the filter 55 is a porous material through which only the excess ink removing liquid can pass. Examples of such a porous material include a non-woven fabric, a woven fabric, and a porous resin film.

The surplus ink removing liquid is a liquid which is incompatible with the printing ink for forming a printed image on the printing image surface of the printing paper P and has a surface tension lower than that of the printing ink. Liquids that satisfy this condition include dimethyl silicone oil, phenyl, polyether, fluorine,
Modified silicone oils such as amino, epoxy, carboxyl, carbinol, methacryl, mercapto and phenol are used. In addition, an aqueous solution containing a surfactant, an organic solvent, etc. is also effective, but most of them are 1
(Cps) or less, and the excess ink removing liquid containing the printing ink may flow out to a portion other than the portion where the excess ink originally flows, which may stain the printed material, and thus it is necessary to make an appropriate selection.

Surfactants to be added to water include anionic, cationic, and amphoteric ionic and nonionic surfactants. The amount of this surfactant added depends on the surface tension of the excess ink removing liquid. It is determined to be lower than the surface tension of the printing ink.

The organic solvent added to water is an organic solvent compatible with water, and examples thereof include methanol, ethanol, isopropyl alcohol, n-propyl alcohol, ethylene glycol and glycerin.

After removing the excess ink, the contact roller 3
7 is evenly coated on the outer peripheral surface 37a, and the coating thickness is preferably about 0.0001 to 1 μm. Converting this to the amount of coating on the material to be printed, 0.1-100 mg / B
It will be about 4 sizes.

The contact roller 37, the facing roller 39, and the blade 45 are made of a material that does not cause swelling or other deterioration due to the excess ink removing liquid. When the main component of the excess ink removing liquid is, for example, silicone oil, the contact roller 37, the facing roller 39, the blade 45.
Is preferably composed of fluorine resin (rubber), phenyl-modified silicone resin (rubber), urethane rubber, or the like.

Next, the operation of the print image post-processing device 29 configured as described above will be described. The printed object P that has been printed is conveyed by being sandwiched between the contact roller 37 and the counter roller 39. The surplus ink removing liquid film a formed on the outer peripheral surface 37a of the contact roller 37 contacts the print image surface of the printing medium P. Due to this contact, of the printing ink b forming the print image on the printing medium P, the surplus printing ink is transferred to the surplus ink removing liquid film a of the contact roller 37, and the surplus printing ink is printed. Removed from body P.

Excess ink removing liquid film a of the contact roller 37
The printing ink c transferred to the sheet passes through the sliding contact portion between the sheet elastic body 49 and the contact roller 37 as the contact roller 37 rotates.

The excess ink removing liquid used in this embodiment is a liquid which is incompatible with the printing ink b forming a printed image and whose surface tension is lower than that of the printing ink c. Therefore, the surplus ink removing liquid film a of the contact roller 37 to which the surplus printing ink c is transferred is formed by the blade 4
When scraped off by 5, the excess ink removing liquid pool f containing the printing ink c in a dispersed state is removed by the contact roller 37.
Occurs on the front side of the blade 45 with respect to the rotation direction.

The surplus ink removing liquid film a containing no printing ink c is regenerated on the outer peripheral surface 37a of the contact roller 37 after passing through the blade 45. Contact roller 37
Since the surplus ink removing liquid film a re-contacts with the print image surface of the print medium P, the print image surface of the print medium P is not contaminated by the print ink c transferred to the contact roller 37.

Outer peripheral surface 3 of blade 45 and contact roller 37
Since the contact position with 7a is on the front side in the direction of rotation from the apex of the contact roller 37, if the amount of the liquid in the excess ink removing liquid pool f exceeds a certain limit, the excess ink is generated even if the contact roller 37 is rotating. The excess ink removing liquid in the removing liquid reservoir f begins to flow in the direction opposite to the rotating direction of the contact roller 37 due to its own weight. The flow of the excess ink removing liquid is guided by the inclined upper surface of the sheet-like elastic body 49 and flows to the receiving tray 5
It falls into 1 and is collected.

The surplus ink removing liquid containing the surplus printing ink is separated from the tray 51 via the discharge pipe 51a to separate means 60.
Of the filter 55 flows into the hole 55a. Filter 55
Is rotated about its central axis by the driving means.
Due to this rotation, centrifugal force acts in a direction perpendicular to the central axis. Due to the action of the centrifugal force and the filter 55, the printing ink and the excess ink removing liquid are separated. This filter 5
No. 5 is stored in the collection container 57, and the separated excess ink removing liquid is collected in the collection container 57. The printing ink separated from the excess ink removing liquid remains in the filter 55. The excess ink removing liquid accumulated in the recovery container 57 is conveyed in the pipe 58 by the pump 59, and is supplied from the excess ink supply nozzle 47 to the contact roller 37 and the blade 47.
It is supplied again to the excess ink removing liquid reservoir f that can be used for use.

As described above, the printing medium P has the contact roller 3
By passing between 7 and the counter roller 39, the surplus of the printing ink b forming the print image as described above is reliably removed from the outer peripheral surface 37a of the contact roller 37. This suppresses the occurrence of set-off and strike-through on the printed substrate, and prevents the printed image from collapsing even if the printed image surface is rubbed with a fingertip or the like immediately after the paper is ejected, and further forms the printed image. The drying of the printing ink b present becomes faster. Also,
The surplus ink removing liquid is economical because it can be used repeatedly.

In the above-described embodiment, the filter 55 has a cylindrical shape, the filter 55 is rotated about the central axis, and the components are separated by passing the liquid through the filter 55 using centrifugal force. However, the shape of the filter is not limited to the cylindrical shape.

Next, Example 1 which is a more specific mode of the above-described embodiment will be described. (Example 1) Stencil printing machine (registered trademark Lithograph RA205
The device of the present invention having the configuration as shown in FIG. 2 was installed in Ideal Science Co., Ltd. For the contact roller, P. T. F. E. FIG. After being baked with (tetrafluoroethylene), a polishing treatment was used. As the blade as a cleaning means, a plate-shaped material of fluororubber was fixed to a metal plate and used.

Dimethyl silicone oil (KF-96 manufactured by Shin-Etsu Chemical Co., Ltd., viscosity:
100 (cps) was used. The coating thickness of the excess ink removing liquid at that time was 0.001 μm.

The filter 55 is made of non-woven fabric (polyester).
Tellur fiber: basis weight 200 (g / m ²))
The rotation speed of the filter 55 was 300 (rpm).

In the evaluation in this Example 1, the excess ink removing liquid containing the printing ink was added to the rotationally driven filter 55 for separation, and the content of the printing ink in the excess ink removing liquid accumulated in the recovery container 57 was used. went. Table 1 shows the results. For reference, without adding rotational drive,
The ink content when the printing ink and the excess ink removing liquid are separated is also shown.

[0048]

[Table 1]

[0049]

According to the present invention, the object to be printed is pressed against the contact member by the facing member, and the printed image surface is brought into contact with the excess ink removing liquid on the surface of the contact member. By this contact, the surplus of the printing ink forming the print image on the printing medium is completely removed. Therefore, the occurrence of set-off and strike-through on the printed material is surely avoided without inducing other obstacles, and the printed image is less likely to collapse even if the printed image surface is rubbed with a fingertip immediately after printing. Become.

The surplus ink removing liquid is a liquid that is incompatible with the printing ink forming the printed image and has a surface tension lower than the surface tension of the printing ink. Therefore, the printing ink transferred to the surplus ink removing liquid layer. Exists on the surface of the excess ink removing liquid layer in a floating state in which it is physically separated from the excess ink removing liquid. Therefore, the surplus ink floating in the surplus ink removing liquid can be removed by a cleaning means such as a blade that comes into contact with the peripheral surface of the contact roller and performs a scraping action.

The excess ink removing liquid containing the removed printing ink is separated into the printing ink and the excess ink removing liquid by the separating means installed in this apparatus. The separated excess ink removing liquid contains almost no printing ink and can be used again without any problem.

【The invention's effect】 [Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is an enlarged view of the print image post-processing device in FIG.

[Explanation of symbols]

 29 Printed Image Post-Processing Device 37 Contact Roller as Contact Member 39 Opposing Roller as Opposing Member 45 Blade as Cleaning Means 47 Excess Ink Removal Liquid Supply Nozzle as Supplying Means 57 Endless Belt as Contacting Means 60 Separating Means P Printing body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sadanao Okuda 2-20-15 Shimbashi, Minato-ku, Tokyo Ideal Science Co., Ltd.

Claims (3)

[Claims] 1. A contact member, which is rotatably driven by applying a surplus ink removing liquid having a surface tension lower than that of the printing ink and which is incompatible with the printing ink for forming a printed image, and is printed between the contact member. The opposite member that transfers excess printing ink of the printing ink forming the print image of the printing object by sandwiching the printing object to the excess ink removing liquid, and removing the excess ink on the contact member. A supply means for supplying a liquid, and a surplus ink removing liquid containing a surplus printing ink supplied in the vicinity of the central axis line, which is driven to rotate around its own central axis line, is passed by the centrifugal force during the rotational drive. A print image post-processing device having a separating means for separating the excess ink removing liquid and the printing ink by doing so. 2. The printed image post-processing apparatus according to claim 1, wherein the separating means has a porous material through which only the excess ink removing liquid can pass. 3. The printed image post-processing apparatus according to claim 2, wherein the excess ink removing liquid separated by the separating unit is supplied to the contact member again and used.