JP2840521B2 - Stencil printing machine having an ink image drying device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stencil printing machine having an ink image drying device.

[0002]

2. Description of the Related Art Emulsion inks generally used in stencil printing machines such as stencil printing plates, simple stencil printing machines, digital stencil printing machines, and lithographic printing presses have pigments dispersed uniformly in non-drying oil or non-volatile oil. An oil phase in which about 90 to 50% of an aqueous phase is emulsified in about 10 to 50% of an oil phase (W / O type), or conversely, an oil phase in which a pigment is uniformly dispersed is emulsified in an aqueous phase ( O / W type). In the stencil printing machine or lithographic printing machine using such an emulsion ink, the ink image formed on the printing paper is slow in "natural drying", and a plurality of printing papers continuously printed by the printing machine are stacked on a tray. When the paper is discharged, there is a problem called so-called "set-off" in which a part of the ink constituting the ink image on the printing paper discharged first adheres to the back surface of the printing paper discharged later. “Natural drying” is a drying method in which the oil phase component of the emulsion ink naturally penetrates into the printing paper and the water phase evaporates naturally. In addition, when touching the ink image immediately after printing, there is a problem that the finger or clothes are stained by the ink, or the ink image is damaged. In particular, in the “ink image immediately after formation” formed by the stencil printing apparatus, the swelling of the ink from the surface of the printing paper is larger than that of the ink image formed by lithographic printing, and the occurrence of the above problem is remarkable.

[0003] In order to solve such a problem, "forced drying" for forcibly drying an ink image immediately after printing is performed.
Is intended. Conventionally, as a forced drying method, a method of continuously heating a printing paper on which an ink image is formed in a non-contact manner by heat from a heat radiating source (Japanese Utility Model Application Laid-Open No. 55-159149).
JP-A-3-9237), and a method in which printing paper is contact-heated while being pressed and conveyed by a heat roller and a pressure roller.
No. 7 publication) is known. However, since the emulsion ink contains a large amount of water, the forced drying method as described above has a problem that "wavy" printing paper may be generated during the drying, or the pigment in the ink may be aggregated. . When the printing paper is wavy, there is a problem that the printed printing paper is likely to be irregular on the tray, and the amount of paper loaded on the tray is reduced. In addition, in the drying method, since heating is continuously performed, when the printing paper is stuck in the heating unit due to insufficient conveyance of the printing paper and is in a so-called “jam” state, there is a possibility that the printing paper may ignite, There is also a problem that it takes a long preparation time to raise the temperature of the heat radiating source and the heating roller to a dryable state.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has no problems such as waving of printing paper and aggregation of pigments, there is no fear of firing of printing paper, and high-speed ink images can be obtained. It is an object of the present invention to provide a stencil printing apparatus having a novel ink image drying apparatus which can be forcibly dried by using the method and does not require a long preparation time until the drying state.

[0005]

SUMMARY OF THE INVENTION A stencil printing apparatus according to the present invention comprises the steps of "wrapping a stencil master made on an outer peripheral surface of a printing drum, supplying emulsion ink from the inner peripheral side of the printing drum, and printing ink on printing paper. Stencil printing machine for forming images "
And an ink image drying device for drying the ink image formed on the printing paper with the emulsion ink, and a blower fan. The ink image drying device has one or more flash lamps, one or more reflectors, and control means. One or more “flash lamps” are provided facing a transport unit that transports the ink image carrier on which the ink image is formed in a predetermined direction. "Reflector"
The light of one or more flash lamps is reflected toward the transport unit.
The “control means” controls flash emission of the flash lamp. The “blowing fan” is for forming an air flow that flows in the print paper transport direction along a transport path that transports the print paper after the ink image is formed toward the discharge unit. It is provided upstream of the image drying device.

The above-mentioned "flash lamp" may be a rod-shaped (tubular lamp) or a so-called "spherical", and one or two or more may be used. When a rod-shaped flash lamp is used, its longitudinal direction may be substantially parallel to the surface of the ink image carrier to be conveyed, and may be provided in parallel to the conveying direction of the image carrier, or may be the conveying direction of the ink image carrier. May be provided so as to intersect. Further, a rod-shaped flash lamp and a spherical flash lamp can be used in combination. When two or more flash lamps are used, they may be provided side by side in the transport direction of the ink image carrier, or they may be provided side by side in a direction parallel to the surface of the transported ink image carrier and perpendicular to the transport direction. Good. The flash lamp can be selected from known ones according to the spectral absorption characteristics of the emulsion ink.
One of the preferable ones is a "xenon lamp having a strong energy spectrum in the visible region and the near infrared region" (Claim 2). The "reflector" reflects the light of the flash lamp toward the ink image carrier transport unit. When two or more flash lamps are provided, one reflector may be provided in common for a plurality of flash lamps, or one reflector may be provided for each flash lamp.
Individuals may be provided. The "control means" includes a power supply for a flash lamp. The emulsion ink constituting the ink image may be a known appropriate one, and may be a W / O
Type or O / W type.

[0007]

The principle of drying an ink image by a flash lamp will be described with reference to FIG. In FIG. 1, a chain line indicated by reference numeral 1 indicates “the surface of the printing paper as viewed macroscopically”. When viewed microscopically, the printing paper is in a complex state of the fibers 2 (showing a cross-sectional state). FIG. 1A schematically shows a state in which the emulsion ink 3 has adhered to the printing paper (a state immediately after an ink image has been formed on the printing paper by the printing apparatus). In this example, the emulsion ink 3 is of a W / O type, and in a 10 to 50% oil phase 5 in which a pigment is dispersed, an aqueous phase 4 (particles having a diameter of about 0.1 to 10 μm, 90% to 50% emulsified). The emulsion ink 3 immediately after adhering to the printing paper partially penetrates between the fibers 2 constituting the printing paper, but partially rises outward from the surface 1 of the printing paper. This state is a state in which the above-described “set-off” or the like occurs.
In the natural drying, the aqueous phase component 4 of the emulsion ink 3 gradually evaporates, while the oil phase component 5 gradually penetrates between the fibers 2 from the state of FIG. Finally, the water layer 4 completely evaporates, and as shown in FIG. 1C, only the oil phase component 5 in which the pigment is dispersed is “thinly attached” to the fibers 2 near the surface layer of the printing paper. Thus, a dried ink image is obtained. In the state shown in FIG. 1C, of course, the above-mentioned “set-off” does not occur, and the ink does not adhere to the hand even when the printing paper is touched. However, as described above, from the state of FIG.
It takes a long time to reach the state (c).

In the present invention, in the state shown in FIG. 1A, that is, immediately after the ink image is formed on the printing paper, the ink image is flashed as shown in FIG. 1B. Light 7 is irradiated. It goes without saying that the flash light is applied to the entire printing paper surface on which the ink image is formed. The flash light 7 enters the emulsion ink 3 in the ink image area, and repeats reflection and refraction at the boundary between the water phase 4 and the oil phase 5. By repeating this reflection and refraction, the flash light is immediately and uniformly diffused throughout the emulsion ink. Light diffused into the emulsion ink 3 and incident on the oil phase 5 is immediately absorbed by the pigment. In a pigment that absorbs light, the absorbed light energy is converted into heat energy, and the pigment generates heat. The heat generated by the heat is immediately diffused through the entire emulsion ink 3 by conduction. Since the fibers 2 around the emulsion ink 3 generally have low thermal conductivity, they act as a "heat insulator" for the emulsion ink 3 in the above diffusion process, and the heat generated in the pigment is only the emulsion ink. Is effectively heated, and the temperature of the entire emulsion ink 3 is increased. The water phase 4 in the emulsion ink 3 almost instantaneously changes in the water vapor 6 due to a rapid temperature rise due to heat (indicated by small arrows directed toward the inside of each granular material of the water phase 4) conducted from the oil phase 5. And evaporates from within the emulsion ink 3.

The oil phase component 5 has a high evaporation point and therefore has a small amount of evaporation, but the viscosity rises due to the above temperature rise and the fluidity increases. Therefore, the oil phase 5 is attached to the fibers 2 while penetrating between the fibers 2 at a “permeation rate higher than that in the case of natural drying”. Thus, in a very short time, FIG.
The dried state of the emulsion ink as shown in (c) is realized. When the ink image of the emulsion ink is naturally dried, "bleeding" of the ink often occurs on the printing paper. However, in the forced drying by irradiating the flash light, the oil phase 5 becomes thicker before the "bleeding" occurs. The ink does not "bleed" in the ink image because it penetrates in the direction.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing a specific embodiment of a stencil printing apparatus having an ink image drying apparatus, an ink image drying apparatus will be described. FIG. 2 shows the most basic form of the ink image drying apparatus. The printing paper S on which the ink image I has been formed is conveyed in the direction of the arrow by conveyance means (not shown). The flash lamp 129 is provided so as to face the surface on which the ink image I of the printing paper S conveyed as described above is formed. Flash lamp 129
Has a bar shape, and is disposed so that its longitudinal direction is perpendicular to the drawing, that is, intersects at right angles to the transport direction of the printing paper S. With respect to the flash lamp 129, a reflector 130 is provided on the side opposite to the printing paper S,
9 is provided so as to partially surround 9 in the longitudinal direction. The surface of the reflector 130 facing the flash lamp 129 is a reflection surface. Reflector 130
Is formed of, for example, an electrolytically polished product of aluminum or the like, and the cross-sectional shape of the reflecting surface is a parabolic shape whose focal point is the position of the axis of the flash lamp 129. Of the reflector 130,
A guide 125 is provided on the side that receives the printing paper S, and a sensor 126 that detects the leading end of the printing paper S is provided on the guide 125. In this example, the sensor 126 is of an optical type, but may be of a contact type using an actuator or the like. Regardless of the optical type or the contact type, the installation position of the sensor is not limited to the position shown in the figure, but may be any position that can detect the leading end of the printing paper S. For example, in FIG. It may be installed on the side opposite to the flash lamp 129 with respect to the road.

The control unit 15 includes a power supply for the flash lamp 129, receives a detection signal of the leading edge of the printing paper S from the sensor 126, and causes the flash lamp 129 to emit flash light at a predetermined timing. The sensor 126 and the control unit 15 constitute "control means". The control of the flash lamp 129 by the control unit 15 is performed as follows. That is, the area indicated by the reference symbol L in the figure is "the area where the ink image is effectively dried by irradiating the flash light". When the sensor 126 detects the leading edge of the printing paper S, the control unit 15 counts a predetermined time by a counter. During this time, the leading end of the printing paper S is
6 is the time required to reach the left end of the area L after being detected by the control unit 6,
It is determined by the distance between the sensor 126 and the left end of the region L. After the elapse of the predetermined time, the control unit 15 causes the flash lamp 129 to emit flash light, and thereafter, repeatedly emits flash light every time the printing paper S "moves in the area L".

When the flash lamp 129 emits flash light, the flash light irradiates the surface of the printing paper S directly or reflected by the reflector 130. In portions other than where an ink image is formed, most of the flash light is reflected. The reflected light is reflected by the reflector 130 and irradiates the printing paper surface again.
In the portion where the ink image I is not formed, the above-mentioned reflection is repeated many times between the surface of the printing paper and the reflector 130, and the ink image I includes “direct light at the time of emission of the flash lamp 129 and the reflector 130”. In addition to "reflected light by light", light irradiation is extremely efficiently performed by secondary light irradiation by repeating the above-mentioned reflection. By the flash light irradiation, the ink image I is instantaneously dried as described above. When the length of the region L is equal to or longer than the length of the printing paper S in the transport direction, it goes without saying that the flash lamp 129 may emit light once per printing paper.

FIG. 3 shows a third modification of the ink image drying apparatus.
Here is an example. In order to avoid complication, the same reference numerals as those in FIG. 2 are used for those which do not seem to be confused.
In FIG. 3, reference numeral 127 indicates a “conveying belt as a conveying unit” of the printing paper S, and reference numeral 128 indicates a “suction fan”. The suction fan 128 is used for bringing the printing paper S conveyed by the conveyance belt 127 into close contact with the conveyance belt 127 to ensure the conveyance. FIG.
In the example shown in (a), in addition to the combination of the flash lamp 129A and the reflector 130A, the combination of the second flash lamp 129B and the reflector 130B is disposed in front and rear close contact in the transport direction of the printing paper S. ing. Various modes are possible for drying the ink image in this example. For example, when the leading end of the printing paper S approaches the left end of the reflector 130B, the flash lamps 129A and 129B can emit flash light simultaneously to simultaneously dry the ink image on the entire printing paper. Alternatively, after the sensor 126 detects the leading end of the printing paper S, the leading end of the printing paper S is emitted from the flash lamp 129A only with the leading end approaching between the reflectors 130A and 130B as shown in the drawing. The first half of the ink image is dried, and subsequently, the printing paper S is conveyed and the rear end of the printing paper S is approaching between the reflectors 130A and 130B. The ink image in the latter half of the transport direction may be dried. In this case, for example, the printing paper S is printed using only the flash lamp 129A.
Compared with the light emission interval of the flash lamp 129A when the flash light is irradiated to the first half and the second half of the transport direction.
Flash lamp 129A and flash lamp 129B
Can be made longer, and the charging time for the flash emission can be made longer, so that the control means has more room. Also, the longer the interval between flash emission, the smaller the average power, so that the specifications required for the power supply can be reduced.

In the example shown in FIG. 3B, two swingable stoppers 16 and 17 are provided along the transport path of the printing paper S, and can enter and exit the transport path by control means (not shown). ing.

When the sensor 126 detects the leading end of the printing paper S, The control means (not shown) rotates the stopper 16 clockwise to place it in the position indicated by the solid line. When the stopper 16 comes into contact with the leading end of the printing paper S, the control means stops the driving of the transport belt 127 and brings the printing paper S into a stopped state. In this state, the flash lamp 129 emits flash light to dry the ink image in the “first half in the transport direction” of the printing paper S.

Next, the control means retracts the stopper 16 from the transport path, places the stopper 17 in the transport path as shown by the broken line, and drives the transport belt 127 again. Then, when the stopper 17 comes into contact with the leading end of the printing paper S, the control means stops the driving of the conveyance belt 127 to stop the printing paper S, causes the flash lamp 129 to emit a flash light, and outputs the printing paper S in the “transport direction”. The second half "
Is dried. During the drying process,
While the driving state of the conveyor belt is maintained, the stoppers 16 and 17
The movement of the printing paper may be stopped only by using. FIG. 3 (c)
In the example shown in FIG.
The transport speed of the printing paper S is different between the transport belt 127A and the transport belt 127A before that. Reference numeral 128A indicates a suction fan. In this embodiment, the transport speed of the transport belt 127 is set to “a transport speed that is lower than the transport speed of the transport belt 127A and is suitable for drying the ink image”, and drying of the ink image is performed by repeating flash light irradiation at a desired timing. It can be performed.

In each of the examples of the ink image drying apparatus shown in FIGS. 2 and 3, a plurality of flash lamps are arranged in a direction perpendicular to the drawing (a direction perpendicular to the conveying direction of the printing paper) as necessary. In this case, in a case where there are a plurality of types of printing paper widths in a direction perpendicular to the drawing, the combination of the light emission of the plurality of flash lamps arranged in the direction may be changed according to the width. Further, a protective glass or a protective wire can be provided on a portion of the reflector on the side of the printing paper transport path so that the printing paper does not enter the flash lamp side. Flash lamp 12
For example, “xenon lamp having a strong energy spectrum in the visible region and the near-infrared region” can be suitably used as 9 or the like. Depending on the color of the emulsion ink, pigments of various colors such as red, blue, green and brown are used in the ink in addition to black, but the light from the xenon lamp is
These various pigments are very efficiently absorbed and generate heat. On the other hand, since the printing paper carrying the ink image does not have a large absorptivity (highly about 20 to 30%) for the light in the energy spectrum region of the xenon lamp, the moisture in the emulsion ink is insulated adiabatically. It is convenient to cause. Since carbon black generally used as a pigment in a black emulsion ink has a high absorptivity in the entire wavelength region, various types of flash lamps other than the xenon lamp can be used.

FIG. 4 schematically shows only an essential part of one embodiment of the "stencil printing apparatus having an ink image drying apparatus" according to the first and second aspects. This stencil printing machine is a digital stencil printing machine. The portion indicated by the reference numeral 51 at the top of the apparatus main body 50 constitutes a "document reading unit", the portion indicated by the reference numeral 52 below it is the "plate making unit", and the reference numeral 53 on the left side is the "print drum". The part indicated by the reference numeral 54 on the left side is a “plate discharging unit”, the part indicated by the reference numeral 55 below the plate making and writing unit 52 is the “paper feeding unit”, and the reference numeral 56
The portion indicated by is a “printing portion”, and the portion indicated by reference numeral 57 at the lower left of the apparatus main body 50 is a “paper discharge portion”.
A feature of this embodiment is that an ink image drying apparatus of the type described with reference to FIG. 2 is provided in a printing paper transport path between the printing pressure section 56 and the paper discharge section 57, and further, an ink image in the transport path is provided. The point is that the blowing fan 124 is provided on the upstream side of the drying device.

Hereinafter, a stencil printing process using the apparatus of this embodiment will be briefly described. First, a document having an image to be printed is placed on a document table (not shown) of the document reading unit 51, and a start button (not shown) is pressed. With the pressing of the start button, first, the "plate discharging process" is executed. That is,
In this state, the stencil master 111 used in the previous printing remains on the outer peripheral surface of the printing drum 53. First, the printing drum 53 rotates in the direction opposite to the direction of the arrow, that is, counterclockwise. The used stencil master 111 held on the outer peripheral surface 109 of the printing drum 53 is also used for the printing drum 5.
3. When the rear end of the stencil master 111 approaches the stencil discharge roller pair 118, the roller pair 118 rotates while one roller scoops up the rear end of the stencil master 111 and conveys it in the direction of the arrow. Stencil master 111
From the outer peripheral surface 109 of the printing drum 53. At this time, the printing drum 53 continues to rotate counterclockwise.

The stencil master 111 conveyed by the plate discharging belt 118 is finally completely peeled off from the outer peripheral surface 109 of the printing drum 53 and discharged into the plate discharging box 120. Then, the compression member 119 descends from above and compresses the stencil master in the plate discharge box 120. When the compression is completed, the compression member 119 is raised to the position shown in the figure and stopped. While this plate discharging process is being performed, the document reading unit 51
Then, "document reading" is performed. That is, a document 101 placed on a document table (not shown) is read by a known “reduced document reading method” using a CCD 103 and discharged onto a document tray 102. Original image information output from the CCD 103 is converted into a digital signal by an image processing unit (not shown). A “plate making process” is performed based on the digital signalized image information. That is, the stencil master is pulled out of the master roll 105 of the stencil writing unit 52 and is moved to the platen roll 104 at the position of the platen roll 104.
4, the image is written by a thermal head 106 provided so as to sandwich the stencil master.

In the thermal head 106, individual minute heating elements are selectively driven to generate heat in accordance with image information sent from the image processing section. During this time, the stencil master continues to be transported intermittently. The stencil master portion in contact with the heat-generating element is melted and perforated. As described above, the image information is written by the position-selective punching of the stencil master corresponding to the image information. The stencil master on which the image information is written is transferred to the printing drum 53 by the master transport roller pair 108.
Is sent out toward the outer peripheral portion, and the traveling direction is changed downward by a guide plate (not shown), and hangs down toward the clamp portion. At this time, the printing drum 53 has already removed the “previous used stencil master” by the stencil discharging process, and the clamper 110 moves upward at a predetermined clamp position where the tip of the hanging new stencil master can be clamped. Open towards. When the clamper 110 clamps the tip of the stencil master sent out from the master transport roller pair 108, the printing drum 53 winds a new stencil master around the outer peripheral surface 109 while rotating clockwise. The rear end of the stencil master on which the image information has been written is cut by the cutter 107.

When the stencil master is wound around the outer periphery of the printing drum 53, the "plate feeding process" is completed and the printing process is started. First, the paper feed roller 113 and the separation roller 114 rotate, and the printing paper 112 as an ink image carrier stacked on the paper board 115 is separated one by one from above and sent to the feed roller pair 116. Feed roller pair 11
Reference numeral 6 denotes a standby state in which the leading end of the printing paper 112 is sandwiched, and sends the printing paper 112 toward the printing unit 56 in synchronization with the movement of the stencil master due to the rotation of the printing drum 53. In synchronization with this feeding, the press roller 117 rotates the printing paper 1
12 is pushed up, and the front side of the printing paper 112 is pressed against the stencil master held on the outer peripheral surface of the printing drum. At this time, the ink roller 12
2 is the ink pool 1 while being in rolling contact with the inner peripheral surface of the printing drum 53.
21 supplies the emulsion ink. Printing drum 5
3 is porous, the supplied ink is applied to the printing drum 5
3, and is supplied to the surface of the printing paper 112 through the perforated portion of the stencil master to form an ink image. The printing paper 112 on which the ink image has been formed in the printing pressure section is separated from the printing drum 53 by the peeling claws 123.
The transport belt 127 rides on the transport belt 127 and is transported toward the paper discharge unit 57 by the counterclockwise rotation of the transport belt 127. At this time, the suction fan 128 operates to bring the printing paper 112 into close contact with the peripheral surface of the transport belt 127 to ensure transport. The flash light from the flash lamp 129 is applied to the reflector 1 with respect to the ink image formed on the printing paper 112 conveyed in this manner.
The light reflected by 30 is irradiated, and the ink image is dried as described with reference to FIG. The printing paper on which the ink image has been dried is sequentially discharged and stacked on the discharge tray 131 of the discharge part 57. When a desired number of prints are obtained in this way, all the printing steps are completed.

As described above, in drying an ink image by irradiating flash light, the water in the emulsion ink is instantaneously turned into water vapor, so that a large amount of water vapor is generated in the printing apparatus in a short time. . Such water vapor may condense inside the apparatus if left unattended, and may have an undesirable effect on the apparatus. Therefore, according to the present invention, the blowing fan 12 is located on the upstream side of the printing paper conveyance path rather than the ink image drying apparatus using the flash lamp 129.
4 is provided so as to generate "air flow toward the outside of the apparatus" along the printing paper transport path. When the ink image is dried by the ink image drying device, the blowing fan 124 is operated, and the steam generated along with the drying of the ink is blown out of the printing device by the airflow. In this way, it is possible to completely prevent water vapor generated due to ink drying from remaining in the printing apparatus.

Using the apparatus shown in FIG. 4 as an emulsion ink, "oil phase: about 10 to 50% by weight and water phase: about 90
And HLB of the surfactant in the oil phase.
Is 3.0 to 5.5, and the aqueous phase contains an acrylic resin or a derivative thereof and is thickened to 15 to 350 poise.
An experiment of the drying effect was conducted using "type emulsion ink". Using the emulsion ink, an ink image was formed on an ordinary printing paper at an image area of 4%. When the ink image was naturally dried to a state where “set-off” did not occur, a drying time of 15 to 30 seconds was required. A xenon lamp was used as the flash lamp 129, and 0.4 J /
Flash light with an energy of cm ² (emission time: 0.1
When forced drying was performed to irradiate for several tens of msec), set-off did not occur at least one second later.

FIG. 5 is a diagram for explaining the difference between the conventionally known method of drying an ink image by a continuous heating method using an infrared heater and the like and the method of drying an ink image by flash light irradiation according to the present invention. In the continuous heating of the ink image drying method using infrared heater or the like, relatively low, constant radiant intensity: W ₂ at the time: between T _2, (a portion indicated by reference sign F ₂₎ that radiation will be be irradiated to the ink image. At this time, the energy consumed for drying the ink image is the area: E ₂ = W ₂
× T ₂ . In contrast, in the method of the present invention, the radiation intensity is very short time: T ₁ Maximum radiation intensity as indicated by the schematic symbols F ₁ within: up W ₁ varies, the energy consumed in the ink drying area: E ₁ ≒ (T ₁ × W ₁ ) / 2. Comparing E ₁ and E ₂ , it was found that E ₁ was smaller than E ₂ . The reason is considered as follows. That is, in the method of continuously heating with an infrared heater or the like, since the infrared rays are absorbed not only in the ink image but also in the printing paper holding the ink image and the whole temperature rises, the heat for drying is the temperature of the printing paper. Also used for climbing. On the other hand, in the drying method by flash light irradiation, as described above, the flash light is hardly absorbed by the ink image carrier, and only the ink image is effectively heated. The minimum energy required to evaporate water is sufficient. As a device for fixing a toner image of a powder in an electronic copying machine, a device that irradiates a flash light is known, and such a flash light irradiating device can be effectively used for carrying out the present invention. In the above description, drying of an ink image using a W / O emulsion ink is described. For example, an ink using an O / W emulsion ink well known in the art such as Japanese Patent Application Laid-Open No. 2-86667 or the like has been described. The invention is very well applicable to drying images.

[0026]

As described above, according to the present invention, a novel stencil printing apparatus having an ink image drying apparatus can be provided. Since the stencil printing apparatus of the present invention is configured as described above, it is possible to completely dry the ink image formed on the printing paper with the emulsion ink in a very short time, and to effectively solve problems such as set-off and save energy. Can be settled. Also, since drying is performed by flash light irradiation, a long preparation time for drying is not required, and the flash light effectively evaporates only the aqueous phase in the ink, so that the printing paper may undulate during drying. Absent. Further, during continuous printing, there is no problem such as set-off even if the printed printing paper is discharged and stacked one after another at a high speed on the discharge section. In addition, since the printing paper is not continuously heated, there is no fear that the ink image carrier may be ignited even if a jam or the like occurs due to insufficient conveyance of the ink image carrier. Further, since a large amount of water vapor generated due to drying of the ink image does not remain in the printing apparatus, there is no possibility that the water vapor may condense inside the apparatus and have an undesired effect on the apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of an ink image drying method according to the present invention.

FIG. 2 shows an ink image drying apparatus used in the present invention.
It is a figure for explaining an example.

FIG. 3 is a diagram showing three modified examples of the ink image drying apparatus used in the present invention.

FIG. 4 is a diagram showing one embodiment of a stencil printing apparatus of the present invention.

FIG. 5 is a diagram for explaining a difference between ink image drying by flash light irradiation and continuous heating type ink image drying.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Macroscopic surface of printing paper 2 Fibers constituting printing paper 3 Emulsion ink 4 Water phase 5 Oil phase 112 Printing paper 124 Blowing fan 129 Flash lamp 130 Reflector

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41L 13/04 B41F 23/04 B41J 2/01 C09D 11/00-13/00

Claims (2)

(57) [Claims] 1. A stencil printing machine which winds a stencil master having been made on an outer peripheral surface of a printing drum and supplies an emulsion ink from the inner peripheral side of the printing drum to form an ink image on the printing paper. An ink image drying device for drying the ink image formed by the emulsion ink, and a blower fan, wherein the ink image drying device is provided in a transport unit that transports the ink image carrier on which the ink image is formed in a fixed direction. At least one flash lamp provided to face, one or more reflectors for reflecting the light of the one or more flash lamps to the transport unit side, and control means for controlling flash emission of the flash lamp; The blower fan transports the printing paper after the ink image is formed along a transport path that transports the printing paper toward the discharge unit. To form an air stream flowing toward the direction,
A stencil printing machine having an ink image drying device, which is provided upstream of the ink image drying device. 2. An ink image drying apparatus according to claim 1, wherein said at least one flash lamp is a xenon lamp having a strong energy spectrum in a visible region and a near-infrared region. Stencil printing apparatus having.