JP2002086675A - Multi-color printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems that when an air knife mechanism with a separating claw is used with a plurality of printing drums, the uniform separation of printing ink cannot be achieved depending upon the extent of a printed image area and consequently, image density irregularities tend to occur and when the printing paper is conveyed in such a state that it is rather curled, the positional deviation of a first and a second color printed image, for example, ensues. SOLUTION: This multi-color printing device comprises hold-down rollers 11a-11d for pressing the printing paper 32 on an impression cylinder 6 to the outer peripheral face of the impression cylinder 6 at the outlet side of a nip part between the printing drums 1a-1d and the impression cylinder 6, hold-down roller displacing means 12a-12d for displacing the hold-down rollers 11a-11d, roller interval varying means 23a-23d and a control means 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor printing apparatus including a multicolor stencil printing apparatus and the like. Related to the device.

[0002]

2. Description of the Related Art As a simpler printing method than before, a stencil printing apparatus of a thermosensitive digital stencil type as an example of a printing apparatus is known. In this stencil printing machine, the master is brought into contact with the fine heating elements of the thermal head, and the master is conveyed while energizing the heating elements of the thermal head in a pulsed manner. The master, which has been made, is wound around the outer peripheral surface of a porous cylindrical plate cylinder (hereinafter sometimes referred to as "printing drum"), and ink is supplied from ink supply means inside the printing drum and fed. The printing paper (hereinafter, simply referred to as “paper”) is continuously pressed against the printing drum through a master that has been prepressed by a pressing means such as a press roller or an impression cylinder, so that the opening portion of the printing drum and the master are pressed. The printed image is formed by exuding ink from the perforated portion and transferring the ink to printing paper.
As a printing technique using such a stencil printing method, 1
Multicolor stencil printing machines capable of multicolor overprinting in a pass (single-sheet passing) are already known. The following two types are known according to the difference in the method of pressing a sheet against a plate-making master on a printing drum.

For example, JP-A-10-297074, JP-A-10-316919, and JP-A-11-13
No. 8961 or JP-A-11-208085 and the like, two (or more) printing drums are arranged side by side in a substantially horizontal state in the paper transport direction, and the paper is placed in two printing drums (or more). A multicolor stencil printing machine that performs two-color (or multicolor) printing by feeding paper to a master that has been made on a printing drum by a press roller used as a pressing unit in the printing unit, It has been disclosed. In the multicolor stencil printing apparatus described above, each of the multicolor stencil printing apparatuses includes a separation claw as a separation unit that separates and separates the printed sheet from the printing drum so that the printed sheet does not wind up on the printing drum. , And an air knife composed of a blowing source such as a fan motor and a baffle member forming a flow path. This printing technique has an advantage that the configuration is simplified and the cost is reduced because the printing section is formed by a press roller (hereinafter, referred to as “first printing technique”).

Japanese Patent Application Laid-Open No. 2000-198262 discloses a paper cylinder (hereinafter, referred to as a cylinder) having substantially the same outer diameter as a printing drum (plate cylinder).
A multicolor stencil printing apparatus using a printing cylinder and a plurality of plate cylinders disposed around a paper cylinder is disclosed. In particular, multicolor stencil printing in which a plurality of (four in FIG. 7 in the same publication) plate cylinders 20A to 20D are arranged around a single paper cylinder 10 as shown in FIG. In the case of the apparatus, the width of the entire printing apparatus in the paper transport direction can be reduced, and since there is no transfer of the paper to another impression cylinder, the paper transportability is excellent, and even if small-size paper is used, There is an advantage that synchronization with each printing drum (plate cylinder) is easy and printing is easy. As shown in FIG. 1 of the above publication, when only a specific plate cylinder (print drum) of a plurality of plate cylinders (print drums) is used for printing, the trailing edge of the sheet is a non-print plate cylinder. Adjacent plate cylinder (printing drum) to prevent contamination by ink
A pair of guide rollers 16 that are driven in contact with the outer peripheral surface of the paper cylinder 10 are disposed therebetween. These guide rollers 16 have a function of pressing non-printing areas at both ends of the paper in the axial direction of the printing drum to prevent the rear end of the paper from separating from the outer peripheral surface of the impression cylinder. . In addition, as shown in FIG. 1 of the above-mentioned publication, usually, a notch 1 is formed on a part of the outer peripheral surface of a printing cylinder (paper cylinder 10) along a generatrix.
1 (hereinafter sometimes referred to as a recess),
A stencil locking portion 22 for locking the leading end of a master provided along a partial generatrix on the outer peripheral surface of a printing drum (printing drum).
(Hereinafter, sometimes referred to as a “clamper”). The paper cylinder 10 is provided with a paper claw 12 (hereinafter, sometimes referred to as a “paper clamper”) that locks one end of the paper, with a notch 11 in the rotation direction of the paper cylinder 10.
Near the training side end.

On the other hand, for example, FIGS. 1 to 6 and FIGS. 8 to 10 of JP-A-11-99735 proposed by the present applicant and FIG.
The impression cylinder (printing impression cylinder) shown in FIGS. 3 to 25 or FIGS. 1, 2, 22, and 26 of Japanese Patent Application Laid-Open No. 2000-33764 serves as holding means for holding the leading end of the sheet. A paper clamper is provided, and the paper clamper is provided to be openable and closable near an end in a recess on the training side (near an upstream end in the recess) with respect to the rotation direction of the printing pressure cylinder.

[0006]

However, in the first printing technique, when small-sized paper (paper short in the paper transport direction) is used, there is a limit on the interval between adjacent print drums. For example, there is a problem in that it is difficult to synchronize the approach from the first color print drum to the second color print drum, and it is difficult to obtain the print image position accuracy in the second color. In addition, in the case of an air knife mechanism having a separation claw for a plurality of print drums, uniform separation cannot be performed depending on the degree of the print image area, resulting in image density unevenness and paper There is a problem that, for example, when the paper is slightly rolled up, the first and second printed images may be misaligned.

On the other hand, the second printing technique has the following problems. That is, since the pair of guide rollers 16 are arranged so as to be driven and fixed between the adjacent plate cylinders, they may come into contact with or interfere with the paper claw 12 near the end of the notch 11. There is. Further, a printing pressure cylinder in which the above-described paper clamper is provided in the concave portion (see the paper clamper shown in FIG. 1 in an embodiment to be described later in addition to the above-described one)
Assuming that the guide rollers 16 are arranged in accordance with FIG. 1 of the above publication, it is inevitable that the guide rollers 16 come into contact with or interfere with the paper clamper,
There is a problem that the guide roller and the paper clamper are damaged.

Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multi-color printing apparatus having a plurality of printing drums and capable of performing multi-color printing and the like.
A multi-color printing device that can handle small-size paper and can evenly separate printed paper from the print drum without causing image density unevenness or misalignment of the printed image. And a press roller (pressing member as a sheet press means) and a sheet clamper (holding means) for pressing the sheet on the printing cylinder against the outer peripheral surface of the printing cylinder are provided. The object of the present invention is to realize a multi-color printing apparatus that does not use the same.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems and to achieve the above-mentioned object, the invention described in each claim has the following characteristic structure. Claim 1
The invention described includes: a plurality of printing drums; and a printing cylinder having a holding unit for holding a leading end of a sheet, wherein the printing drums are arranged around the printing cylinder, and each printing drum is provided. By pressing relatively to the impression cylinder, in a multicolor printing apparatus capable of multicolor printing, the paper on the impression cylinder at the exit side of the sandwiching area between each printing drum and the impression cylinder, It is characterized by having a paper pressing means for pressing against the outer peripheral surface of the printing cylinder.

Here, the "pressing each printing drum relatively to the impression cylinder" method is a printing impression cylinder which performs printing by pushing the printing cylinder against each printing drum via a master which has been made. There are a contact / separation method, a printing drum contact / separation method in which each printing drum is pressed against the impression cylinder via a master having been made to perform printing, and a combination method thereof.

In the printing drum contact / separation method, an entire drum contact / separation method in which the entire printing drum is pressed toward the impression cylinder, or an intermediate press roller in the printing drum is pushed out toward the impression cylinder, and only the printing drum plate cylinder is pressed. There is a plate cylinder extrusion method. As a specific example of the whole drum contacting / separating method, a paper holding cylinder and its contacting / separating means as an impression cylinder in a first embodiment to be described later can be cited. On the other hand, the print drum contact / separation method includes a known method in which each print drum moves toward the impression cylinder (including a type in which an ink supply roller or the like inside the print drum projects toward the impression cylinder) to perform printing. . As the plate cylinder extrusion method, for example, JP-A-1-204781, JP-A-3-197078, or JP-A-3-25498
A so-called middle-press roller system (including one that also serves as an ink supply roller) that swells a metal screen as disclosed in Japanese Patent No. 4 and the like from inside to outside. There are two types of printing cylinders having an outer diameter (diameter) larger than the outer diameter (diameter) of the printing drum as in the embodiment described later, and those having substantially the same diameter as the outer diameter of the printing drum.

According to a second aspect of the present invention, in the multicolor printing apparatus according to the first aspect, the paper pressing means is a pressing roller for pressing both side edges of the paper on the printing cylinder against the printing cylinder. It is characterized by the following.

According to a third aspect of the present invention, in the multicolor printing apparatus according to the second aspect, the pressing rollers provided corresponding to the respective printing drums are provided with a pressing position for contacting the printing cylinder and the printing position. In order to avoid contact with the holding means arrangement portion of the impression cylinder, there is provided a pressing roller displacing means for displacing from the pressing position to a non-pressing position separated outward from the printing pressure cylinder.

The invention described in claim 4 is the invention according to claim 2 or 3.
The multicolor printing apparatus according to any one of the preceding claims, further comprising a roller interval changing unit that changes an interval between the pressing rollers in a sheet width direction according to a sheet size.

According to a fifth aspect of the present invention, in the multicolor printing apparatus according to the fourth aspect, a driving unit for driving the roller interval changing unit, a sheet size detecting unit for detecting a sheet size, and the sheet size detecting unit. And control means for controlling the driving means so as to vary the interval between the pressing rollers in the sheet width direction based on the output signal from the control means.

According to a sixth aspect of the present invention, in the multi-color printing apparatus according to the first aspect, the sheet pressing means urges the sheet on the impression cylinder between the printing drum and the impression cylinder by blowing air. It is a blower that presses against the outer peripheral surface of the printing cylinder at the outlet side of the sandwiching region.

According to a seventh aspect of the present invention, there is provided a printing drum having a plurality of printing drums and a holding means for holding a leading end of a sheet, wherein the plurality of printing drums are provided around the printing pressure cylinder. In a multicolor printing apparatus capable of performing multicolor printing by arranging and pressing each printing drum relatively to the impression cylinder, an outlet side of a region sandwiched between each printing drum and the impression cylinder has At both the downstream printing drum of the adjacent printing drums and the entrance side of the sandwiching region between the printing pressure cylinders, a blowing unit for pressing the paper on the printing pressure cylinders to the printing pressure cylinders is provided. It is characterized by having.

The invention according to claim 8 is the invention according to claim 6 or 7.
In the multicolor printing apparatus described above, the blowing means includes a blowing source for generating an air flow, and an air flow from the blowing source, the printing drum and the printing pressure cylinder sandwiching region outlet side, or the sandwiching region outlet. And a wind guide member that forms a flow path for guiding the sheet to the printing pressure cylinder by guiding the sheet to both the side and the sandwiching area entrance side.

According to a ninth aspect of the present invention, in the multicolor printing apparatus according to the eighth aspect, the air guide member is provided in a sheet transport path located near an upstream printing drum among the adjacent printing drums. A flow path for blowing airflow from the air supply source is formed at an upstream end of the paper feed path and at a downstream end of the paper transport path located near a downstream print drum among the adjacent print drums. Features.

According to a tenth aspect of the present invention, in the multicolor printing apparatus according to the eighth or ninth aspect, a sheet information inputting means for inputting sheet information, and the blower according to the input information from the sheet information inputting means. Control means for controlling the operation of the source.

According to an eleventh aspect of the present invention, there is provided the multicolor printing apparatus according to the tenth aspect, further comprising an air volume setting unit connected to the control unit, wherein the control unit responds to a signal from the air volume setting unit. The operation of the air supply source is controlled separately from the input information from the paper information input means.

According to a twelfth aspect of the present invention, in the multicolor printing apparatus according to the tenth aspect, the paper information input means outputs a signal corresponding to the type of the paper to the control means; And a sheet size setting means for outputting a signal corresponding to a sheet size to the control means.

According to a thirteenth aspect of the present invention, in the multi-color printing apparatus according to any one of the second to fifth aspects, the printing cylinder is provided at an exit side of a sandwiching region between each of the printing drums and the printing cylinder. It is characterized by having a blowing means for pressing the upper sheet against the outer peripheral surface of the printing cylinder.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention including embodiments with reference to the drawings (hereinafter, simply referred to as "embodiments").
Will be described. Throughout each embodiment and the like, for components such as members and components having the same function and shape,
The description is omitted as much as possible by attaching the same reference numerals. For the sake of simplicity of the drawings and the description, even if they are components to be shown in the drawings, components that do not need to be specifically described in the drawings may be appropriately omitted without omission. In the drawings, components that are configured as a pair and do not need to be specifically distinguished and described will be replaced with the description by appropriately describing one of them in order to simplify the description. (First Embodiment) FIGS. 1 to 4 show a first embodiment according to claims 1 to 5 of the present invention. In FIG. 1, reference numeral 100 denotes a multicolor stencil printing apparatus as an example of a multicolor printing apparatus to which the present invention is applied. As shown in FIG. 1, the multicolor stencil printing apparatus 100 includes a plurality of stencils (4 in the first embodiment) around which a stencil master 12 is wound.
) Printing drums 1a, 1b, 1c and 1d (hereinafter abbreviated as "printing drums 1a to 1d") and a paper clamper 7 as a holding means for holding the leading end of the fed paper 32. Further, a printing pressure cylinder 6 also called a paper holding cylinder is provided.

Printing cylinder 6 driven to rotate counterclockwise
Around the four printing drums 1 a having an axis parallel to the axis of the impression cylinder 6 and having a larger diameter than the impression cylinder 6.
1 to 1d are arranged in this order in the vicinity of the printing cylinder 6 and along the rotation direction of the printing cylinder 6 (also the paper transport direction X). The multicolor stencil printing apparatus 100 includes printing drums 1a to
The multi-color stencil printing is enabled by sequentially pressing the master 10 on the outer periphery of the impression cylinder 6 on the outer peripheral surface of the impression cylinder 6 on the master 1d.

Further, the multicolor stencil printing apparatus 100 directs the paper 32 placed on the paper feed table 31 disposed to the right of the impression cylinder 6 and the printing drum 1 a toward the paper clamper 7 of the impression cylinder 6. The paper feed device 30 for feeding and the printed paper 32 printed below at least one of the printing drums 1 a to 1 d disposed below the impression cylinder are printed onto a paper output tray 43. A paper discharging device 40 for discharging paper and the printing drums 1a to 1
d, are arranged in the vicinity of the printing drums 1a to 1d,
A plate-making / plate-feeding device (not shown) for plate-making the master 10 and supplying the plate-making master 10 to the printing drums 1a to 1d;
Printing drums 1a to 1d corresponding to printing drums 1a to 1d
And a plate discharging device (not shown) for separating and storing the used master 10 on the printing drums 1a to 1d,
A document reading device (not shown) arranged near the plate making / plate feeding device to read a document image;

The printing drums 1a to 1d are configured so as to be capable of coming into contact with and separating from the printing pressure cylinder 6 by a known configuration to be described later. While ink is being supplied to the plate-making master 10 on the printing drums of the printing drums 1a to 1d, during printing, the printing operation is performed by swelling and displacing to the printing pressure cylinder 6 side to perform a pressing operation. Printing drum 1a on paper 32 held in
Printing can be performed continuously by successively pressing the masters 10 on which a plate has been made on the plate cylinder of 1 to 1d, thereby enabling simultaneous multicolor printing (simultaneous four-color printing in the first embodiment). Is configured.

In the first embodiment, by having the above-described configuration, advantages similar to those of the second conventional printing technique can be obtained, that is, the width of the entire multicolor stencil printing apparatus 100 in the paper transport direction X can be reduced. The paper is not transferred to the paper holding cylinder or the intermediate transport unit, so that the paper transportability is excellent, and even if the small-sized paper 32 having a short length in the paper transport direction X is used, the printing drums 1a to 1d There is an advantage that it is easy to synchronize with and print easily.

Since the printing drums 1a to 1d have substantially the same functions and the same components except for the color and arrangement position of the ink, the reference numerals a, b, The distinction is made by adding “c” or “d”, and when they are described in detail with the print drum 1a as a representative, other descriptions will be omitted to avoid redundant description.

In the first embodiment, the master 1 having been made
0, the printing roller 1a to 1d is pressed against the impression cylinder 6 to perform printing. 6, a printing cylinder extruding method of pressing only the printing drums of the printing drums 1a to 1d is adopted. As the plate cylinder extruding method, for example, Japanese Patent Application Laid-Open No. 1-20
No. 4781, JP-A-3-197078 or JP-A-3-254984.
In this method, a metal screen made of an ink-permeable mesh material is swelled from the inside to the outside by a middle press roller as a plate cylinder (including a plate that also serves as an ink supply roller).

Each of the printing drums 1a to 1d
The rotation is driven in synchronism with the direction opposite to the printing cylinder 6, that is, clockwise, about a, 2 b, 2 c, and 2 d. As shown in FIG. 1, an openable and closable clamper 5a is provided on one bus line of the outer peripheral portion of the printing drum 1a as a master holding means for clamping (clamping) and holding the leading end of the master 10 after plate making. . Clamper 5
a is pivotally mounted on the printing drum 1a by a clamper shaft. When stopped at a predetermined position, the clamper 5a is opened and closed by an opening and closing device (not shown).

In the first embodiment, the printing drum 1a of the first color on the most upstream side in the sheet conveying direction X in the printing pressure cylinder 6 performs one printing.
The printed image of the color is printed on the paper 32 with, for example, magenta (M) color (hereinafter, referred to as “red”) ink,
Next, the second color printing drum 1b converts the second color print image into, for example, yellow (Y) color (hereinafter, referred to as “yellow”).
Then, the third color print image is printed on the paper 32 by the print drum 1c using, for example, cyan (C) color (hereinafter, referred to as “blue”) ink. The printed image is printed on the paper 32 in a manner superimposed on the printed image of the color, and then the printed image of the fourth color is printed with the black (Bk) color (hereinafter referred to as “black”) ink on the most downstream printing drum 1d. The image can be printed on the sheet 32 so as to be superimposed on the print image of the color. Thus, the printing drums 1a to 1d are always driven to rotate with a predetermined initial phase difference.

Inside the printing drum 1a, an intermediate press roller (not shown) containing ink and an ink supply section are arranged. The intermediate pressing rollers in the printing drums 1a to 1d are respectively red ink, yellow ink, blue ink,
Contains black ink. These not-shown middle push rollers are arranged so as to roll while contacting the inner circumferential surfaces of the print drums 1a to 1d on the outer circumferential surface.

The first and second middle-press roller driving mechanisms for driving the respective middle-press rollers are described, for example, in JP-A-2000-1.
2 to FIG. 4 of JP-A-98262, and further includes a printing cylinder 6 and a printing drum 1.
The drive system for connecting a to 1d is also the same as that shown in FIG. That is, the impression cylinder 6
It is rotationally driven by a main motor via a rotation transmission system via a gear (not shown). In addition, the printing drums 1a to 1
d denotes the drum shafts 2a to 2d of the printing drums 1a to 1d.
The gears (not shown) fixed to the gears mesh with the gears on the printing pressure cylinder side, whereby the gears are rotated without phase shift.
By the first and second middle-press roller driving mechanisms, each of the middle-press rollers is moved to an operating position (for example, each print drum 1 shown in FIG. 1) at which printing can be performed on the sheet 32 held on the impression cylinder.
b, 1c, and 1d, where the plate cylinders are swelled and deformed as shown by exaggerated enlargement by two-dot chain lines) and a non-operating position (for example, printing shown in FIG. (A position where the plate cylinder of the drum 1a is not deformed).

As described above, the printing cylinder 6 enables the use of the small-sized paper 32 that is short in the paper transport direction X, improves the printing registration accuracy for the paper 32, stabilizes the image density, and reduces the printing time. It is used to reduce noise. The printing cylinder 6 is a pressed unit (pressed member) with the adoption of the plate cylinder extruding method. Impression cylinder 6
As shown schematically in FIG. 1, the outer diameter (diameter) is formed larger than the outer diameter (diameter) of the printing drum 1a.

In FIG. 1, the printing cylinder 6 is rotated in a counterclockwise direction, and the leading end of the paper 32 is set at the rotation position of the paper clamper 7 on the printing cylinder 6 (hereinafter, sometimes referred to as the “paper holding position”). Is pressed against the sheet clamper 7 and then the sheet clamper 7 closes, whereby the leading end of the sheet 32 is clamped and held by the sheet clamper 7. Next, the printing cylinder 6
Is further rotated in the counterclockwise direction, and the paper clamper 7 of the impression cylinder 6 is slightly advanced from a position where the paper clamper 7 of the printing drum 1d on the most downstream side is opposed to the intermediate pressing roller and the pressing roller 11d (hereinafter, “paper discharging”). The paper clamper 7 is opened at the position, and the leading end of the paper 32 is discharged at a position beyond the printing portion (nip portion) as a sandwiching region of the printing drums 1a to 1d where the ink is transferred to the paper 32. Therefore, there is also an advantage that the paper 32 is unlikely to wind up around the printing drums 1a to 1d due to the adhesive force of the ink.

The printing drums 1a to 1a
A cylindrical portion that comes into contact with the outer peripheral surface of 1d via the master 10 that has been made and a concave portion 8 that is recessed to avoid contact / collision with the clampers 5a to 5d of the printing drums 1a to 1d are formed. To put it concretely, the printing cylinder 6 is made of synthetic resin for its main body to reduce the weight, and for example, nitrile rubber is wound around the outer periphery of the cylindrical portion, so that the printing pressure is reduced. The rotation unevenness of the body 6 is reduced. The impression cylinder 6 is rotatably supported around a shaft 9 arranged at its center.

An openable / closable paper clamper 7 for clamping and holding the leading end of the paper 32 is provided near the upstream end in the recess 8 on the training side with respect to the rotation direction of the printing cylinder 6. The paper clamper 7 employs a clamp method using a magnet and a paper clamper 7.
Has its base end fixed to a paper clamper shaft arranged in the concave portion 8 and is always urged to close by a spring (not shown). The paper clamper 7 is opened at a predetermined timing by a cam (not shown) arranged on the printing apparatus main body side, and holds the paper 32 on the outer peripheral surface of the impression cylinder 6 by closing after holding the leading end of the paper 32. . The details of the structure around the paper clamper 7 are described in, for example, FIGS. 1 to 6 and FIGS. 8 to 10 of Japanese Patent Application Laid-Open No. H11-99735, and FIGS. 25, or JP-A-2000-3
It is the same as that disclosed in FIG. 1, FIG. 2, FIG. 22, FIG. The formation range of the concave portion 8 of the printing pressure cylinder 6 is determined by the clamper 5a of the printing drums 1a to 1d.
-5d is set with a specific range and phase relationship to avoid contact / collision with 5d. That is, the concave portion 8 and the clampers 5a to 5d of the printing drums 1a to 1d are configured to rotate in synchronization with each other in synchronization with each other.

The sheet feeding device 30 is press-contacted with an elevator-type vertically movable sheet feeding table 31, a call roller 33 and a separation roller 34 rotatably supported by a sheet side plate (not shown), and a separation roller 34. It mainly comprises a separation pad 35 for preventing double feeding of the sheet 32, and a pair of registration rollers 36 for sending out the leading end of the sheet 32 at a predetermined timing toward the sheet clamper 7 of the impression cylinder 6.

The paper feed table 31 has sheets 32 loaded thereon, and is supported by the printing apparatus main body so as to be able to move up and down. The paper feed table 31 is moved up and down by a motor device (not shown) in conjunction with the increase and decrease of the paper 32. The call roller 33 is provided on the sheet feeding table 31.
The separation roller 34 and the separation pad 35 have a function of separating the sheet 32 sent out by the calling roller 33 into one sheet by the cooperation thereof. . The paper feeding means for separating the paper 32 one by one and feeding the leading end of the paper 32 toward the pair of registration rollers 36 is composed of the above-mentioned call roller 33, separation roller 34 and separation pad 35.
The call roller 33 and the separation roller 34 are in a rotational transmission relationship via a rotation transmission member such as a pulley and a belt, and are rotationally driven by a paper feed motor (not shown) arranged independently of the main motor. Is done. Registration roller pair 36
Is driven to rotate by a registration motor (not shown) provided independently of the main motor. The sheet feeding motor and the registration motor are, for example, stepping motors.

As shown in FIG. 3, a pair of side fences 47, 47 for positioning and aligning both side edges of the sheet 32 in accordance with the sheet size, are movably provided in the sheet feeding table 31 in the sheet width direction Y, as shown in FIG. Have been. FIG. 3 shows a paper size detection mechanism. This paper size detection mechanism determines the paper size of the paper 32 in conjunction with the movement of the pair of side fences 47, 47 in the paper width direction Y. The paper size detection mechanism includes a pair of side fences 47, a pinion 46 rotatably mounted on and supported by an immovable member disposed below the paper feed table 31, and a side near the paper surface in FIG. The pinion 4 formed at the lower edge of the fence 47
6, a rack portion 44 formed at the lower edge of the side fence 43b and facing the rack portion 45 and meshing with the pinion 46, and a rack portion of the side fence 43 on the far side in FIG. A shielding portion 44a provided with a plurality of notches which are protruded downward and bent at appropriate intervals at a lower edge portion opposing the lower edge portion 44 and are cut out at appropriate intervals.
And two lateral size detection sensors 48a and 48b fixed to the immovable member of the sheet feeding table 31 at appropriate intervals and selectively engaged with the shielding portions 44a, respectively, and the immovable state of the sheet feeding table 31. It mainly comprises a vertical size detection sensor 49 fixedly provided at an appropriate interval in the paper transport direction X of the member.

Each of the horizontal size detection sensors 48a and 48b is
This is a transmission type optical sensor having a light emitting unit and a light receiving unit, and detects the size of the sheet 32 in the sheet width direction Y by selectively engaging with the shielding unit 44a.
The vertical size detection sensor 49 is a reflection type optical sensor, and detects the size of the paper 32 in the paper transport direction X. Each of the horizontal size detection sensors 48 a and 48 b and the vertical size detection sensor 49 constitutes a paper size detection sensor group 50 in the paper feeding device 30, and a paper size detection unit that detects the paper size (size) of the paper 32. It has the function of The CPU 26 of the control unit 25 shown in FIG. 4 determines the paper size (size) by combining the size signal data detected by the paper size detection sensor group 50 with the CPU 26.

The details of such a paper size detection method include a technique proposed by the applicant of the present application and disclosed in, for example, JP-A-9-30714. The paper size detection method is not limited to the method described above, and it goes without saying that another method may be used. Further, in the paper size detecting mechanism of the paper feed table 31 in FIG. 3, the number of each detection sensor is limited for simplification of description, but as described above, many paper types are output from the paper feed table 31. In order to be able to feed paper, it is assumed that each of the above-described detection sensors is increased and attached so that the paper size of, for example, a postcard, an envelope, or a legal size paper 32 can be automatically detected.

The paper discharging device 40 is provided at the most downstream side of the printing drum 1.
and a discharge claw 42 that is disposed diagonally below and to the left of the press roller 11d and that delivers and discharges the printed paper 32 that has been printed in multicolor by the printing section of the printing drums 1a to 1d. It is mainly composed of a well-known paper discharge transport unit 41 for forcibly adsorbing and transporting the transferred printed paper 32 with a porous transport belt and discharging it onto a paper discharge table 43, and a paper discharge table 43. Is done. The paper discharge transport unit 41 has a configuration similar to that shown in, for example, FIG. 1 of JP-A-10-297074, and performs a known operation.

The multicolor stencil printing apparatus 100 has a specific configuration described below. That is, as shown in FIG. 1 and FIG.
a to 1d, the paper 32 on the impression cylinder 6 is discharged at the exit side of a region between the printing drums 1a to 1d and the impression cylinder 6 (hereinafter referred to as "printing section" or "nip section"). Pressing rollers 11a, 11b, 11c, 1 as sheet pressing means (sheet pressing member) for pressing against the outer peripheral surface of the impression cylinder 6
1d (hereinafter abbreviated as "pressing rollers 11a to 11d") and pressing roller displacement means 12a, 12b, 1 for displacing the pressing rollers 11a to 11d as described later.
2c, 12d (hereinafter referred to as "pressing roller displacement means 12a-1
2d), and variable-spacing means 23a, 23b provided with slide drive motors 20a, 20b, 20c, 20d (hereinafter abbreviated as "slide drive motors 20a to 20d") as drive means to be described later. 23
c, 23d (hereinafter referred to as “roller interval variable units 23a to 23d”).
d ") and control means 25 shown in FIG.

Since the pressing rollers 11a to 11d have substantially the same function and the same components except for the arrangement position, the reference numerals a, b, c or d are added to the end of the same reference numerals including those components. In addition, when they are described in detail with the press roller 11a as a representative, the other description will be omitted to avoid redundant description. Hereinafter, in the same manner as described above, each of the pressing roller displacing means 12a to 12d is
In the case where 2a is described in detail with the roller interval varying means 23a as a representative of the roller interval varying means 23a to 23d, other explanations including those components will be omitted to avoid redundant explanation.

The pressing rollers 11a to 11d are arranged near the outer periphery of the printing cylinder 6 near the exit side of the sandwiching region between the printing drums 1a to 1d and the printing cylinder 6. Pressing roller 11a
Has a function as a sheet pressing member that presses the non-print image areas on both side edges of the sheet 32 held on the printing cylinder 6 via the sheet clamper 7 and presses the non-printed image area against the printing cylinder 6. For this reason, the pressing roller 11a is formed of a suitable solid rubber, sponge rubber, or the like so as not to damage the paper 32, the outer peripheral surface of the impression cylinder 6, or the pressing roller 11a itself.

The pressing roller displacing means 12a moves the pressing roller 11a in order to prevent the pressing roller 11a from touching the pressing position where it contacts the outer peripheral surface of the outer cylindrical portion of the printing pressure cylinder 6 and the portion where the paper clamper 7 of the printing pressure cylinder 6 is disposed. And a structure and a function of displacing between the pressing position and a non-pressing position that is substantially radially outward of the printing cylinder 6. The press roller displacing means 12 a
A pair of roller oscillating cams 13 provided on both end plates of the impression cylinder 6 for retracting and displacing to the non-pressing position so as not to contact the disposition portion, and driven by rotation of each roller oscillating cam 13. A pair of cam followers 14 that engage with each other, each cam follower 14 is rotatably supported, and each press roller 11
and a roller pressing spring 15 (compression spring) as a pair of urging means for constantly urging each of the pressing rollers 11a toward the pressing position via the roller supporting frame 16. And a pair of roller support brackets 18 that rotatably support each holding roller 11a, and a guide member 19 that connects each roller support bracket 18 and the roller support frame 16.

A guide (not shown) for guiding the displacement of the roller support frame 16 is provided on the printing apparatus main body side. Each of the roller support brackets 18 has a female screw that is screwed with a right screw and a left screw (male screw) formed on the slide drive shaft 17 described later. Guide member 19
Has a substantially half-moon-shaped cross section, and each roller support bracket 1
In the screwed state of the female screw 8 and the male screw of the slide drive shaft 17, each roller support bracket 18 is moved so as to move linearly and not to swing in the left-right direction in FIG. Restrict movement. The urging force of the roller pressing spring 15 is applied to each of the pressing rollers 11a to 11a.
Depending on the displacement direction and the own weight at the arrangement position of d, the pressing roller 11a on the most upstream side and the pressing roller 1 on the most downstream side
It should be noted that the values need to be set larger in order from 1d.

The roller interval changing means 23a has a function and structure for changing the interval between the pair of pressing rollers 11a in the sheet width direction Y according to the sheet size. The roller spacing variable means 23a includes a slide drive motor 20a fixedly mounted on one outer wall of the roller support frame 16 via a motor bracket 20A, a slide drive gear 21 fixedly mounted on an output shaft of the slide drive motor 20a, Roller support frame 1
6 is a slide drive shaft 1 rotatably supported, formed with a right-hand screw and a left-hand screw, and a slide driven gear 22 meshing with a slide drive gear 21 attached to one end thereof.
7, each roller support bracket 18 formed with a female screw to be screwed with a right screw and a left screw (male screw) formed on the slide drive shaft 17, and each roller support bracket 18 linearly moves in the paper width direction Y. And a guide member 19 for restricting the movement of the guide member. On the back side of the roller support bracket 18 in FIG.
Are fixedly protruding. On the other hand, a roller home position sensor 24 for detecting the home position of each pressing roller 11a by being selectively engaged with the light shielding plate 18A is fixedly provided on the printing apparatus main body side. The slide drive motor 20a is composed of, for example, a stepping motor.

Referring to FIG. 4, roller interval varying means 23
The control configuration will be described on behalf of a. As shown in FIG. 4, the control configuration of the roller interval varying unit 23a includes a sheet size detection sensor group 50 as the sheet size detecting unit shown in FIG. 3, a slide driving motor 20a of the roller interval varying unit 23a, and a roller home. A position sensor 24,
On the basis of an output signal relating to the sheet size from the sheet size detection sensor group 50 and an output signal from the roller home position sensor 24, the interval between the pair of pressing rollers 11a is varied in the sheet width direction X in accordance with the sheet size. The control unit 25 mainly controls the drive motor 20a. The control configuration of the roller interval variable means 23b to 23d is the same as described above (see the slide drive motors 20b to 20d in FIG. 4).

The control means 58 includes a CPU 26 (central processing unit), a RAM 27 (readable and writable storage device),
OM28 (read only memory), timer and I / O
A microcomputer having an O (input / output) port (not shown) and the like is provided. The control means is not limited to one having a microcomputer, but may be a control circuit or the like.

Next, the operation of the multicolor stencil printing machine 100 will be described. First, a case where four-color printing is performed using the printing drums 1a to 1d will be described.

First, when a user sets an original on an original mounting table (not shown) or a contact glass of an ADF (not shown) provided in the original reading apparatus, and presses a print start key on an operation panel (not shown), a plate making start signal is issued. Are generated and input to a control device (not shown), whereby the plate discharging operation, the document reading operation, and the plate making operation are started simultaneously. At this time, the pair of side fences 47, 47
The sheet size is detected by the sheet size detection sensor group 50 in accordance with the operation of moving the sheet 2 in the sheet width direction Y in order to position and align both side edges of the sheet 2, and an output signal relating to the sheet size is transmitted to the CPU 26 of the control means 25. You.

The CPU 26 of the control means 25 determines the interval between each pair of pressing rollers 11a to 11d in the sheet width direction Y based on the output signal relating to the sheet size and the output signal from the roller home position sensor 24. Slide drive motors 20a-2
0d is controlled. That is, the roller interval variable means 23a
The slide drive motor 20a is rotated by a predetermined number of steps in an appropriate rotation direction (forward / reverse rotation) corresponding to the paper size, so that the slide drive gear 21 and the slide driven gear 22 mesh with each other. Is transmitted, and the slide drive shaft 17 is rotated in an appropriate rotation direction corresponding to the paper size in accordance with the rotation, so that each roller support bracket 18 and the pair of pressing rollers 11 a are guided by the guide member 19. The paper 32 moves linearly in the paper width direction Y via the screw mechanism while being moved to predetermined positions on both side edges of the paper 32 corresponding to the paper size to be held on the impression cylinder 6. At this time, the uppermost sheet 32 loaded on the sheet feeding table 31 is called out.
3 until the sheet can be fed by contacting
Is raised.

On the other hand, when the main motor is driven, the printing drums 1a to 1d rotate in the clockwise direction in FIG.
A well-known discharging operation is performed in which the used masters 10 to 1d are peeled off and discarded in a not-shown discharging box. Next, the master 1 provided in each of the plate making / plate feeding devices is provided.
A known plate making is performed by a thermal head for making a plate 0, a platen roller for transporting the master 10, and a plate feeding roller pair (both not shown) for feeding and feeding the plate 10 to the clamper of each printing drum. The plate-feeding operation is performed, and the plate-made master 10 that has been made to correspond to the print image of each color is wound on each of the print drums 1a to 1d.
When the winding of the master 10 having been made on the printing drums 1a to 1d is completed, the sheet feeding / printing operation is started.

When the printing operation starts, the printing drums 1a to 1a
An intermediate press controller (not shown) that controls the operation of an intermediate press roller (not shown) of 1d is provided with signals from a rotational position detection sensor (not shown) that detects the rotational position of the paper clamper 7 and the rotational position of the concave portion 8 in the printing pressure cylinder 6. , The printing operation is started in order from the most upstream printing drum 1a, that is, by sequentially moving the not-shown intermediate pressing rollers of the printing drums 1a to 1d to the operating positions, so that the inks of the respective colors are printed on the respective printing drums 1a to 1d. It is supplied to the inner circumference side of 1d.

Next, the uppermost sheet 32 that is in contact with the call roller 33 is sent out by rotating the call roller 33 together with the separation roller 34 by driving the paper feed motor. The registration roller pair 3 is separated into one by the cooperation of the separation pad 35 and guided by a pair of upper and lower guide plates (not shown).
6 is fed in the sheet transport direction X. Next, by driving the registration motor, the sheet 32 is fed by the registration roller pair 36 after a predetermined timing synchronized with the rotation of the printing drum 1a for the first color, and is fed in synchronization with the timing. 6 rotates counterclockwise to occupy the paper holding position.

At this timing, FIG.
As shown in (b), the large-diameter portions of the pair of roller swing cams 13 and the pair of cam followers 14 engage with each other against the urging force of the pair of roller pressing springs 15 of the pressing roller displacement means 12a. become. Then, the roller support frame 1
6. Guide member 19 and pair of roller support brackets 1
2 (a) and 2 (b), the respective pressing rollers 11a occupy the non-pressing positions which are spaced substantially radially outward of the impression cylinder 6. As a result, each of the pressing rollers 11a is separated from the portion of the printing cylinder 6 where the paper clamper 7 is disposed, so that each of the pressing rollers 11a does not come into contact with the paper clamper 7 or the like. I will not receive it. The pressing roller displacement means 12b to 12d also perform the same operation as described above at the timing when the large diameter portion of each roller swing cam 13 and each cam follower 14 are engaged, and the same effect as described above is obtained.

On the other hand, if the printing cylinder 6 occupies the paper holding position, the paper clamper 7 of the printing cylinder 6 is opened and the leading end of the paper 32 is abutted. In addition. Next, the paper clamper 7 is closed, and while the paper 32 is held on the outer peripheral surface of the impression cylinder 6, the impression cylinder 6 is further rotated in the counterclockwise direction. The sheet 32 is sent to the printing section (nip section). At this time, the printing drum 1a is moved to the operating position, whereby the plate cylinder is swelled so as to contact and press the sheet 32 on the printing pressure cylinder 6, and thus the plate cylinder on the printing drum 1a is swelled. Is pressed against the paper 32 on the printing cylinder 6. At the time of this pressing, the red ink supplied to the inner peripheral surface of the first color printing drum 1a by the middle pressing roller passes through the perforated portion of the plate-making master 10 on which the first color plate-making image is formed and bleeds. The exuded ink is transferred to the surface of the paper 32 to form a red print image.

At this time, each cam follower 14 of the pressing roller displacement means 12a is engaged with the outer peripheral surface of the roller swing cam 13 having substantially the same diameter as the printing pressure cylinder 6, and the urging force of each roller pressing spring 15 is applied. As a result, the roller support frame 16, the guide member 19, the roller support brackets 18, and the pressing rollers 11a are displaced downward in FIGS. 2A and 2B together. As a result, each press roller 11a occupies the press position in contact with the outer peripheral surface of the outer cylinder portion of the printing pressure cylinder 6, and
The sheet 3 held on the impression cylinder 6 near the printing section (nip) exit side between the printing drum 1a of the color and the impression cylinder 6
The roller 2 is rolled following the rotation of the printing cylinder 6 while holding the non-print image areas on both side edges of the printing press cylinder 2. Therefore, both side edges of the paper 32 held and printed by the paper clamper 7 can be reliably separated from the first color printing drum 1a and pressed against the outer peripheral surface of the printing cylinder 6, thereby causing image density unevenness. Or the paper 32 is rolled up irrespective of the thickness of the paper 32 (generally, it is hard to be rolled up with thick paper or a postcard having a large thickness of the paper 32, and it is not necessary to add the paper with the paper clamper 7). Also, there is no displacement of the print image. Such an operation is also performed by the pressing roller displacement means 12b to 12d at the timing when each cam follower 14 engages with the contour outer peripheral surface of each roller swing cam 13 having substantially the same diameter as the printing pressure cylinder 6 as described above. The same effect as described above can be obtained. It should be noted that the effect of preventing the displacement of the printed image becomes more significant as the printing operation is performed on the downstream side in the rotation direction of the printing pressure cylinder.

When the impression cylinder 6 holding the paper 32 on which the red print image is formed is further rotated in the counterclockwise direction, the paper 32 on which the red print image is formed becomes the second color printing drum 1b. Printing section (nip) between the printing press and the impression cylinder 6
Is rotated and conveyed, and the yellow print image is superimposed on the red print image and printed on the paper 32. Similarly,
The blue print image is printed on the paper 32 by the third color print drum 1c so as to overlap the red and yellow print images, and then the black print image is printed in red, yellow, and blue colors by the fourth most downstream print drum 1d. The print image is printed on the sheet 32 so as to be superimposed on the print image, and finally a print image of four colors is printed on the sheet 32.

The printed paper 32 on which the printed images of four colors are formed is occupied by the printing cylinder 6 in the counterclockwise direction to occupy the paper discharge position. When the sheet 7 is opened, the sheet 7 rides on the sheet ejection claw 42 and is peeled off, and is ejected onto the conveyance belt located below while being sucked by the suction fan of the sheet ejection conveyance unit 41. The printed paper 32 on the conveyance belt is conveyed by the rotation of the suction / discharge exit roller while being sucked onto the conveyance belt by the suction fan, and is discharged onto the paper discharge table 43 to complete the so-called plate printing. The printed matter discharged by this printing is usually not counted as a regular printed matter.

After completion of the printing, the user visually checks the discharged printed matter, appropriately judges whether or not to perform a normal regular printing operation, and confirms image quality and image position. Is appropriately performed. If these are OK, the user sets the number of prints with ten keys (not shown) provided on the operation panel, and presses a print start key (not shown), thereby making a proper print. The operation (process) is started, and the same paper feed, print, and paper discharge processes as those of the stencil printing are repeated at the set print speed for the set number of prints, and the entire stencil printing process is completed.

In the first embodiment, for example, a specific printing drum 1d among a plurality of printing drums 1a to 1d
In the case where monochrome (black) printing is performed only with the printing drum (that is, the printing drum arranged on the downstream side), the pressing rollers 1a to 1c that can be displaced between the non-pressing position and the pressing position are used on the impression cylinder 6. If the rear end of the sheet 32 is pressed, the first to third color printing drums 1a to 1c (that is, the printing drum arranged on the upstream side) need not be applied with the printing pressure. Since there is no contact with the print drums 1a to 1c, it is possible to easily prevent stains on the image and damage to the master. (Second Embodiment) A second embodiment according to claims 6 to 9 will be described with reference to FIGS. In FIG. 5, reference numeral 200 denotes a multicolor stencil printing apparatus to which the second embodiment is applied. The multicolor stencil printing apparatus 200 of the second embodiment differs from the multicolor stencil printing apparatus 100 of the first embodiment in that a printing drum is used instead of the pressing rollers 11a to 11d shown in FIGS. The exit side of a region (printing portion or nip portion) between the printing drums 1a to 1d and the adjacent printing drums 1a to 1d (that is, the printing drum 1a and the printing drum 1b, the printing drum 1b and the printing drum 1)
c, both of the printing drums (that is, the printing drums 1b, 1c, 1d) on the downstream side of the printing drums 1c and 1d) and the inlet side of the sandwiching region (printing portion or nip portion) between the impression cylinder 6 The blowing means 145a, 145b, 1 for pressing the paper 32 on the impression cylinder 6 against the outer peripheral surface of the impression cylinder 6
45c (hereinafter abbreviated as "blowing means 145a to 145c"), a paper discharging device 40A having a paper discharging and blowing means 59 in place of the paper discharging device 40, and the control shown in FIG. The main difference is that a control configuration shown in FIG. 7 is provided instead of the configuration, and an operation panel 170 shown in FIG. 8 is provided.

Since the blowing means 145a to 145c have substantially the same functions and the same components except for the respective arrangement positions, a code a, b or c is added to the end of the same code including those components. In the case where the air blower 145a is used as a representative and detailed description is given as a representative, other explanations will be omitted as much as possible to avoid redundant explanation. Further, each of the blowing means 145a to 145a
5c, blower fans 146a to 146c, wind guide members 148a to 148c, and blower motors 149a to 149c.
The code a, b or c is added to only 149c.

The blowing means 14 which is a main part of the second embodiment
5a will be described. The blowing means 145a supplies a blowing fan 146a serving as a blowing source for generating an air flow, and blows the blowing air as the air flow generated by the blowing fan 146a to a printing unit (nip) outlet of the printing drum 1a and the impression cylinder 6. Side, in other words, the upstream end 14 of the paper transport path on the impression cylinder 6
7a and the printing section (nip) entrance side of the printing drum 1b and the impression cylinder 6, in other words, both the downstream end 147b of the sheet transport path on the impression cylinder 6 to guide the sheet 32 to the impression cylinder 6. And a wind guide member 148a that forms a plurality of flow paths for pressing against the air flow.

The blower fan 146 a has a blower motor 149.
a, the printing drum 1a and the impression cylinder 6 are rotated.
A suitable airflow (blast) is generated both toward the printing section (nip section) exit side of the printing drum 1b and the printing section (nip section) entrance side between the printing drum 1b and the impression cylinder 6. .

As shown in FIG. 6, the inside of the air guide member 148a is integrally formed from the outside of the air guide plate 151, 152 and the inside of the air guide plate 153, 154.
It is fixedly provided on the printing apparatus main body side in the space between the printing drums 1a and 1b. The air guide member 148a is arranged to increase the separation / peeling performance of the printed paper 32 from the print drum 1a and is biased toward the printing portion (nip portion) exit side of the printing drum 1a and the impression cylinder 6. Are located. Outside the wind guide plate 151, 152 and inside the wind guide plate 153, 154
Is formed to have a width somewhat longer than the length of the printing drums 1a and 1b in the generatrix direction. Outside the air guide plate 151,1
52 is an outer peripheral surface 1a of the printing drums 1a and 1b, respectively.
The print drums 1a and 1b are formed at a position that does not contact the clampers 5a and 5b when the print drums 1a and 1b rotate. The upper ends 151a, 152a of the outer wind guide plates 151, 152 extend to a case 46a for accommodating the blower fan 146a.
Blower 1 in the main flow path 155 formed by
46a is located.

The insides of the air guide plates 153 and 154 are formed to be curved along the outer peripheral surfaces 1aa and 1ba of the printing drums 1a and 1b, respectively. It is arranged below the outside of the air guide plate 151, 152 in a character shape. Upper end 1 of 153, 154 in the air guide plate
53a and 154a are lower ends 1 of the outside 151 and 152 of the baffle plate.
It is arranged inside the outlet 156 of the main flow path 155 formed between 51b and 152b. As a result, the main flow path 155 is divided near the outlet 156, and the three branch flow paths 157, 158,
159 are formed. Lower end 153b of 153 in the air guide plate
Extends to the vicinity of the printing section exit side of the printing drum 1a and the impression cylinder 6 in a range that does not contact the paper clamper 7 (not shown in FIG. 6) of the impression cylinder 6.

The branch flow path 157 is formed between the outer peripheral surface 1aa of the printing drum 1a and the outer surface of the inside of the air guide plate 153.
The outlet 157a is arranged near the printing unit outlet side of the printing drum 1a and the impression cylinder 6 (which is also the upstream end 147a of the paper transport path on the impression cylinder 6). Branch channel 159
Is formed between the outer peripheral surface 1ba of the printing drum 1b and the outer surface of the inside of the baffle plate 154, and its outlet 159a is located closer to the entrance side of the printing portion (nip portion) between the printing drum 1b and the impression cylinder 6. (It is also the downstream end 147b of the paper transport path on the printing cylinder 6). The branch flow path 158 is formed between the insides 153 and 154 of the baffle plate, and its outlet 158.
a is disposed on the outer peripheral surface of the printing cylinder 6 near the printing unit outlet side of the printing drum 1a and the printing cylinder 6.

As described above, the air guide member 148a is connected to the upstream end of the paper transport path on the printing cylinder 6 near the upstream printing drum 1a of the adjacent printing drums 1a and 1b. Of the adjacent printing drums 1a and 1b, each as a flow path for blowing the air flow from the blowing fan 146a to the downstream end of the paper transport path on the printing cylinder 6 located near the downstream printing drum 1b. Branch flows 157, 158, 159 are formed.

The paper discharging and blowing means 59 includes a paper discharging and blowing fan 60 as a blowing source for generating an air flow (blowing), and a paper discharging and blowing motor 61 for driving the discharging and blowing fan 60 to rotate.
Then, the air blown from the discharge fan 60 is guided to press the paper 32 on the printing cylinder 6 against the outer peripheral surface thereof at the printing unit outlet side of the printing drum 1d and the printing cylinder 6 on the most downstream side (in other words, An air guide path forming unit 6 that forms a flow path and the like for blowing air between the printed paper 32 adhered to the outer peripheral surface of the printing drum 1d by the adhesive force of the ink and the outer peripheral surface of the printing drum 1d.
2 mainly.

As shown in FIG. 8, a numeric keypad 171 for setting the number of prints and a print start signal for generating and outputting a print start signal for setting activation of each operation up to the printing process are provided on the operation panel 170, as shown in FIG. A key 172, a plate making start key 173 for generating and outputting a start signal for activating each operation from reading of an image of a document to plate making, plate feeding, and plate printing as test printing; A stop key 174 for stopping the operation,
A display 175 composed of an LED (light emitting diode display) for displaying the number of prints and the like set by the ten keys 171 and the master 10 in the multicolor stencil printing apparatus 200
Display unit 176 for displaying a failure location such as a jam of paper or paper 32 and the details of the failure, and a ten-key 171
Key 177 for canceling the number of prints set by the user, a down key 178a and an up key 178b.
, An air volume selection key 144 as an air volume setting device, a paper type selection key 143 as a paper identification device for identifying the type of the paper 32, and a paper size setting device for setting the size of the paper 32. And a paper size selection key 179 respectively. The paper type selection key 143 and the paper size selection key 179 each constitute paper information input means. Note that the paper type selection key 143, the air volume selection key 144, the adjustment key 178, and the paper size selection key 179 are not used in the second embodiment, and therefore may not be the operation panel 170 of the second embodiment.

The control means 134, as shown in FIG.
PU (Central Processing Unit) 180, I / O not shown
(Input / output) port and ROM (read only storage device) 181, RAM (read / write storage device) 182
And a microcomputer having a configuration in which they are connected by a signal bus (not shown). Various keys of the operation panel 170 and a display device 175 are electrically connected to the control means 134, and send and receive command signals and / or on / off signals and data signals between them.

The blower motors 149a to 149c are electrically connected to the CPU 180 via a motor drive circuit (not shown). Then, when a print start signal generated by pressing the print start key 72 of the operation panel 170 is input to the control means 134, the control means 134 operates as a start signal.

The CPU 180 is electrically connected to a paper discharge / blow motor 61 via a motor drive circuit (not shown). The print start key 9 on the operation panel 90 shown in FIG.
When the print start signal is input to the control unit 134 by pressing the button 2, the operation is performed using the start signal as a start signal. For this reason, the paper discharging and blowing means 59 has a function of peeling and separating to prevent the printed paper 32 from winding up on the printing drum 1d.

Further, in addition to the above-described controlled object driving means, the CPU 180 also includes the paper discharge transport unit 4 of the paper discharge device 40A.
1, a paper discharge system drive unit 18 including a suction fan motor for rotatingly driving the suction fan in the printer 1 and a belt drive motor (not shown) connected to a drive roller for driving the transport belt.
4, a paper feed system driving unit 185 including the paper feed motor, the registration motor, etc., the impression cylinder 6, and each printing drum 1.
a to 1d are electrically connected to each other, and transmit and receive a command signal and / or an on / off signal and a data signal to and from the main motor 161 to drive each of the units. It controls the entire operation system such as starting, stopping and timing of the mechanism. The control unit 134 temporarily stores input information from sensors (not shown) and the calculation results of the CPU 180 in the RAM 182, and reads out the information as needed.

The ROM 181 stores the multicolor stencil printing apparatus 20.
Programs and necessary data relating to operations such as start, stop, and timing of each of the drive units 0 are stored in advance. In particular, in the second embodiment, when a print start signal is input, the blower motors 149a to 149c and the paper discharge blower motor 61 are driven. I have.

The multicolor stencil printing apparatus 200 having such a configuration
The separation / separation operation of the sheet 32 will be described.
When the print start key 172 is pressed and a print start signal is input to the control means 134, the blower motors 149a to
149c, the paper discharge blower motor 61 and the paper discharge system drive unit 18
4, the suction fan motor and the belt drive motor (not shown) are respectively driven, and the blower fans 146a to 146a-1 are driven.
The rotation of 46c starts the blowing of the airflow, that is, the airflow is blown to the outer peripheral surface of the printing cylinder 6 between the printing drums 1a and 1b.

When the leading end of the paper 32 on which the first color print image is formed reaches the exit at the printing portion (nip portion) of the printing drum 1a for the first color and the impression cylinder 6, the air is blown from the blowing fan 146a and branched. Outlet 15 of flow path 157
The air flow blown from 7a is blown from above onto the leading end of the paper 32, and the leading end of the paper 32 attached to the outer peripheral surface 1aa of the first color printing drum 1a is separated and separated by the waist of the paper 32 itself. Even when the paper 32 tends to curl up, such as a thin paper having no stiffness, or when a large amount of ink adheres and the adhesive force between the paper 32 and the first color printing drum 1a is large, the curl up is reduced. The leading end of the separated sheet 32 is pressed against the outer peripheral surface of the printing cylinder 6 by the airflow blown from the outlet 157a. For this reason, even if the leading end of the sheet 32 is slightly lifted and conveyed in the printing portion (nip portion) of the printing drum 1a of the first color and the printing cylinder 6,
Is transported so as to be in close contact with the outer peripheral surface of the
And the so-called image double or print image position shift does not occur.

When the sheet 32 conveyed in the sheet conveying direction X with its leading end held by the sheet clamper 7 of the printing cylinder 6 reaches the area of the outlet 158a of the branch flow path 158, the sheet 32 is discharged from the outlet 158a. The blown air flow is blown onto the upper surface of the paper 32, and the paper 32 is pressed against the outer peripheral surface of the impression cylinder 6 and is brought into close contact therewith. For this reason, the flapping of the paper 32 on the outer peripheral surface of the printing cylinder 6 is extremely reduced.
Therefore, the conveyance delay is also reduced at the entrance of the printing portion (nip portion) between the printing drum 1b for the second color of the paper 32 and the impression cylinder 6 due to the shortage of the conveying force, and the image doubling is further reduced.

The above-described operation is performed by the blowing means 145b in the paper transport path on the printing drum 6 between the printing drum 1b and the printing drum 1c, and the printing cylinder 6 between the printing drum 1c and the printing drum 1d. This is similarly performed by the blowing means 145c in the upper sheet transport path. The paper 32 on which the black print image of the fourth color is formed is blown by the wind guide member 62 from the paper discharge fan 60 of the paper discharge blower 59 so that the paper 32 becomes the print drum of the fourth color. 1d
Separated and peeled off without rolling up from The air sent by the rotation of the discharge fan 60 is blown onto the surface of the printed sheet 32. This is also to promote ink drying of the printed image on the printed paper 32.

In the second embodiment, the branch channels 157, 1
Although 58 and 159 are formed over the entire sheet transport path on the impression cylinder 6, the present invention is not limited to this. Paper 3
If the second print drum 1a has a strong tendency to wind up, for example, the wind guide path forming unit 62 of the paper discharge blowing unit 59 arranged corresponding to the fourth lowermost print drum 1d.
A flow path for blowing the airflow from the blower fan 146a may be formed only at the upstream end 147a, as in the blowout outlet of FIG.

Further, the lower end 151b, 152b of the outer 151, 152 is not provided without the inside 153, 154 of the wind guide.
Are extended so as not to come into contact with the paper clamper 7 to the vicinity of the outer peripheral surface of the printing cylinder 6, and the air flow is blown from the main flow path 155 to the whole, so that the configuration of the air guide member 148 a can be simplified. Workability is also improved. When the outlet 156 of the main flow path 155 is divided to form the branch flow paths 157, 158, and 159 as in the second embodiment, each of the branch flow paths 1
Since the inlets of the air flow to 57, 158, and 159 are narrowed, the flow velocity of the air flow can be increased, and the blowing force on the paper 32 can be reduced as compared with the case where the air flow is blown out only from the outlet 156 of the main flow path 155. Can be strong. (Third Embodiment) A third embodiment of the present invention will be described with reference to FIG. 5, FIG. 6, FIG. 8, and FIG. The third embodiment is the first embodiment.
In addition, the second embodiment is characterized in that the amount of air generated by the blower fan 146a in the second embodiment is controlled so as to be changed according to the type of the paper 32. Specifically, FIG.
Blowers 146a to 146 using control means 90 shown in FIG.
6c controls the rotation of the blower motors 149a to 149c.

The control means 190 includes a CPU 191, an I / O (input / output) port (not shown), a ROM 192,
M193, etc., and a well-known microcomputer having a configuration in which these are connected by a signal bus (not shown). The control unit 190 includes the operation panel 17
The various kinds of keys, the display device 175, and the paper type selection key 143 are electrically connected to each other to transmit and receive command signals and / or on / off signals and data signals. The paper type selection key 143 includes a key switch 143a for selecting thick paper, a key switch 143b for selecting standard thickness paper, and a key switch 143c for selecting thin paper. ing.

The CPU 191 is electrically connected to blower motors 149 a to 149 c via a voltage varying device 194, in addition to those similar to the control target drive means in the second embodiment. The control unit 190 is configured to temporarily store input information from each sensor (not shown) and a calculation result of the CPU 191 in the RAM 193, and to read out the information at an appropriate time. The ROM 192 stores in advance programs and necessary data relating to operations such as starting, stopping, and timing of the multicolor stencil printing apparatus and each drive unit. In particular, in the third embodiment, when a print start signal is input, the blower motors 149a to 149c
And the voltage variable device 194 is electrically operated in accordance with data for stopping the driving when the set number of prints is completed or input information from the paper type selection key 143, and the blower motors 149a to 149c are driven. Voltage control data for switching the voltage is stored.

The voltage control data is stored in the key switch 143a.
Is input to the CPU 191, the voltage controller 194 controls the voltage variable device 194 so that the voltage supplied to the blower motors 149a to 149c becomes lower than the reference voltage. ,
By controlling the voltage variable device 194 so that the voltage supplied to the blower motors 149a to 149c is higher than the reference voltage,
When a signal from the key switch 143b is input to the CPU 191, it controls the voltage variable device 194 so that the voltage supplied to the blower motors 149a to 149c becomes the reference voltage.

According to the stencil printing apparatus having the control means 190 having such a configuration, the sheet 3
When 2 is thick, the key switch 143a is pressed.
Then, the voltage variable device 194 is controlled so that the voltage supplied to the blower motors 149a to 149c becomes lower than the reference voltage, so that the rotation of the blower fans 146a to 146c per unit time decreases, and this fan generates. The air volume per unit time is reduced. Therefore, the flow rate of the air blown to the sheet 32 via the branch channels 157, 158, and 159 shown in FIG. 6 is reduced.

When the sheet 32 loaded on the sheet feeding table 31 is thin, when the key switch 143c is pressed, the voltage variable device 194 controls the voltage supplied to the blower motors 149a to 149c to be higher than the reference voltage. As a result, the rotation of the blowing fans 146a to 146c per unit time increases, and the amount of air generated by the fans per unit time increases. Therefore, the branch channels 157, 158,
The flow rate of the air blown to the sheet 32 via 159 increases.

When the paper 32 is thick, the paper 32 has a stiffness and has good separation and peeling properties from the printing drums 1a to 1c.
Since there is no problem even if the rotation of the blower motors 149a to 149c is suppressed, by suppressing the rotation of the blower motors 149a to 149c, the heating of the blower motors 149a to 149c can be reduced to increase the durability of the motor and save energy of the device. I can do it. When the paper 32 is thin, the paper 32 has no rigidity and sticks to the printing drum 1a, so that the separation / peelability is not good.
By increasing the rotation of 49c and increasing the flow rate of air blown between the leading end of the paper 32 and the outer peripheral surface of the printing drum, the separation / separation property can be improved. By operating the paper type selection key 143 in this manner, the blowing motor 149a
When the amount of air flow blown onto the sheet 32 is automatically adjusted by controlling to 149c, it is possible to further reduce image double while shortening the adjustment time.

[0092] The embodiment of the present invention is not limited to the above-described one, and it is needless to say that the second embodiment and the third embodiment can be added to the first embodiment. 13). Further, the printing drum of the present invention is not limited to the printing drums 1a to 1d of the so-called middle-press roller type described above. For example, similar to the plate cylinders 1a and 1b shown in FIG. It has a two-layer structure consisting of a metal sheet layer-like support cylinder having a large number of fine holes (not shown) that allow ink passage, and a resin or metal mesh screen layer wound around the outer peripheral surface. It may be. In this case, it suffices to have at least an ink-permeable metal sheet layer (same as the supporting cylinder), and the mesh screen layer may be omitted or a plurality of layers may be provided. An ink supply roller having such a so-called highly rigid plate cylinder, a doctor roller which is disposed in parallel with the ink supply roller at a slight gap to form an ink reservoir between the ink supply roller, and an ink reservoir When using a printing drum having an ink supply means including an ink distributor and the like (not shown) for supplying ink to the printing drum, the printing drum can be brought into contact with and separated from the outer peripheral surface of the impression cylinder 6. It is desirable to provide appropriate contact / separation means.

The configuration and the arrangement of the units and devices constituting the multicolor stencil printing apparatus 100 shown in the first embodiment and the multicolor stencil printing apparatus 200 of the second embodiment are not limited to the above. This is an example, and it goes without saying that all other equivalent known units and devices may be configured in various arrangement states, or known units and devices may be added. In the first to third embodiments, for simplicity of description, the four printing drums 1a
However, the embodiments of the present invention are not limited to the above-described embodiments, and may be configured to include five or more print drums or five or more print drum units. It should be noted that, of course, the following effects can be obtained. As described above, the present invention has been described with respect to the specific embodiments and the like including the examples, but the configuration of the present invention is not limited to the above-described embodiments and the like, and may be configured by appropriately combining these. It will be apparent to those skilled in the art that various embodiments and examples can be configured according to the necessity, application, and the like within the scope of the present invention.

[0094]

As described above, according to the present invention,
It is possible to provide a novel multicolor printing apparatus by solving the problems of the conventional apparatus as described above. The effects of each claim are as follows. Claims 1 and 2
According to the described invention, both side edges of the paper on the printing cylinder are pressed against the printing cylinder at the exit side of the sandwiching region between each printing drum and the printing cylinder by the pressing roller as the paper pressing means. In addition to being able to cope with paper of a size, it is possible to perform uniform separation of the printed paper from the print drum, thereby preventing image density unevenness and a shift in the position of a printed image.

According to the third aspect of the present invention, the pressing roller provided for each printing drum is moved by the pressing roller displacing means to the pressing position where the pressing roller comes into contact with the printing pressure cylinder, and the holding means for the printing pressure cylinder is arranged. In order to avoid contact with the pressing portion, the pressing member can be displaced from the pressing position to a non-pressing position that is separated from the printing pressure cylinder outwardly. It is possible to prevent the printed image from being stained by contact with the print drum due to the jumping up due to the use of the small-size paper or the floating due to the use of the thin paper, and to prevent the holding means of the press roller and / or the impression cylinder from being damaged. Further, for example, in the case of a two-color printing apparatus, it is possible to displace between the non-pressing position and the pressing position without applying printing pressure to the first-color printing drum during single-color printing with the second-color printing drum. If the pressing roller presses the rear end of the paper on the printing cylinder, it does not come into contact with the printing drum of the first color, thereby preventing the image from being stained and the master from being damaged.

[0096] According to the fourth aspect of the present invention, the variable roller spacing means allows the manual or automatic
Since the interval between the pressing rollers can be changed in the paper width direction according to the paper size, in addition to the effect of the invention described in claim 2 or 3, ink in an unset (undried) state on printed paper is provided. By soiling each press roller, it is possible to prevent the printed paper (printed matter) from being stained with ink.

According to the fifth aspect of the present invention, the control means controls the driving means based on the output signal from the paper size detecting means so as to change the interval between the pressing rollers in the paper width direction. In addition to the effects of the invention described in Item 4, it is not necessary to perform a troublesome operation of manually changing the interval between the pressing rollers, for example.

According to the sixth aspect of the present invention, the paper on the impression cylinder is pressed against the outer peripheral surface of the impression cylinder by the air blow from the air blowing means as the sheet pressing means. In addition to the effect, the paper to be printed can be separated from the print drum in the entire paper width direction and pressed against the impression cylinder, so that it can be evenly separated from the print drum, eliminating uneven density and curling of the paper In addition, dirt such as ink does not adhere to the paper.

According to the seventh aspect of the present invention, not only can a small-sized sheet be accommodated, but also the air blow means can provide an outlet side of a sandwiching area between each printing drum and the impression cylinder and each adjacent printing drum. The paper on the impression cylinder is pressed against the impression cylinder both on the downstream side of the printing drum and on the entrance side of the area between the impression cylinder, so that the uniformity of the printed paper from the printing drum is uniform. Separation can be performed, so that image density unevenness does not occur, a position shift of a printed image does not occur, and contact of a sheet with the next printing drum can be prevented.

According to the eighth aspect of the present invention, the printing drum and the impression pressure cylinder at the exit side of the sandwiching area or the printing drum and the impression pressure cylinder at the exit side of the sandwiching area and the printing drum and the impression cylinder at the sandwiching area. Since the air flow generated by the air supply source is efficiently guided and blown to both the paper transport paths on the inlet side, the separating performance of the paper with respect to the upstream printing drum is improved, and the paper is formed on the outer peripheral surface of the impression cylinder. Claim 6 or 7
In addition to the effects of the invention described above, image double due to misalignment of a printed image can be reduced.

According to the ninth aspect of the present invention, the air flow is simultaneously blown to the two positions on the sheet transport path by the air source and the air guide member of the air blowing means. In addition, the separation performance between the adjacent upstream printing drum and the paper and the performance of the paper entering the downstream printing drum are improved at the same time, and image doubling can be further reduced.

According to the tenth aspect of the present invention, the amount of air generated at the air supply source is controlled by the control means in accordance with the input information from the paper information input means, so that the amount of air generated on the paper conveying path on the printing pressure cylinder is reduced. Since the amount of air flow blown to the paper can be adjusted in a short time, in addition to the effects of the invention according to claim 8 or 9, the separation performance between the printing drum and the paper at the more upstream side is improved and the image doubling is achieved. Can be further reduced.

According to the eleventh aspect of the present invention, the amount of air blown to the sheet conveyed on the sheet conveyance path can be varied by adjusting the amount of air generated by the air supply source independently of the sheet information input means by the air amount setting means. Since the control is performed, in addition to the effect of the invention described in claim 10, even if there is a trouble in the control system by the paper information input means, the performance of separating the upstream printing drum from the paper can be improved, and the adjustment time can be improved. , Image stabilization can be reduced stably.

According to the twelfth aspect, according to the first aspect,
In addition to the effects of the invention described in Item No. 0, the paper conveyance path is conveyed by controlling the amount of air generated by the air supply source and the area of the flow path, or both the amount of generated air and the area of the flow path according to the type and size of the paper. Can automatically or semi-automatically increase or decrease the amount of air flow blown to the paper to be printed, further improve the separation performance between the printing drum and the paper on the upstream side, and more reliably reduce image doubling. it can.

According to the thirteenth aspect, the second aspect is provided.
In addition to the effects of the invention described in any one of (5) to (5), the paper to be printed can be separated from the printing drum in the entire width direction of the paper and pressed against the impression cylinder, so that uniform separation from the printing drum can be achieved. The density unevenness and the curling of the paper are eliminated, and the stain such as ink does not adhere to the paper.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a multicolor stencil printing apparatus to which a first embodiment of the present invention is applied.

FIG. 2A is a side view of a main part of a press roller displacing means and a roller interval varying means in the first embodiment, and FIG. 2B is a front view of a main part showing both means in the first embodiment.

FIG. 3 is a perspective view of a main part showing a paper size detecting mechanism of the multicolor stencil printing apparatus in FIG. 1;

FIG. 4 is a block diagram illustrating a control configuration according to the first embodiment.

FIG. 5 is a front view of a main part of a multicolor stencil printing apparatus to which a second embodiment of the present invention is applied.

FIG. 6 is an enlarged cross-sectional view illustrating a configuration and an operation of a blowing unit according to a second embodiment.

FIG. 7 is a block diagram illustrating a control configuration that is a main part of a second embodiment.

FIG. 8 is a partially broken plan view showing a configuration of an operation panel of the multicolor stencil printing apparatus according to the second and third embodiments.

FIG. 9 is a block diagram illustrating a control configuration that is a main part of a third embodiment.

[Explanation of symbols]

1a, 1b, 1c, 1d Printing drum 6 Impression cylinder 8 Recess 10 Master 11a, 11b, 11c, 11d Pressing rollers 12, 12b, 12c, 12d as sheet pressing means Pressing roller displacement means 20, 20b, 20c, 20d Drive Slide drive motors 23, 23b, 23c, 23d Roller interval variable means 25, 134, 190 Control means 32 Paper 50 Paper size detection sensor group 100, 200 as paper size detection means Color stencil printing apparatus 145a, 145b, 145c, 145d Blowing means 146a, 146b, 146c Blowing fan 148a, 148b, 148c Blowing member 170 Operation panel 143 Paper type selection key as paper information input means 179 Paper information input Means and paper Paper size selection key as the size setting means

Claims (13)

[Claims] 1. A printing drum comprising a plurality of printing drums and a printing cylinder having a holding means for holding a leading end of a sheet, wherein the printing drums are arranged around the printing cylinder. Is pressed relatively to the impression cylinder, in a multicolor printing apparatus capable of multicolor printing, the paper on the impression cylinder at the exit side of the sandwiched area between each printing drum and the impression cylinder, A multicolor printing apparatus comprising a paper pressing means for pressing against an outer peripheral surface of a printing cylinder. 2. A multi-color printing apparatus according to claim 1, wherein said paper pressing means is a pressing roller for pressing both side edges of the paper on said printing cylinder against said printing cylinder. Color printing device. 3. The multi-color printing apparatus according to claim 2, wherein said press rollers provided for each printing drum are provided with:
Displaced between a pressing position in contact with the printing impression cylinder and a non-pressing position separated from the pressing position to the outside of the printing pressure cylinder in order to avoid contact with the holding means arrangement portion of the printing pressure cylinder. A multi-color printing apparatus comprising a press roller displacing means for causing the press to be displaced. 4. A multi-color printing apparatus according to claim 2, further comprising a roller interval changing means for changing an interval between said pressing rollers in a sheet width direction according to a sheet size. Printing device. 5. A multi-color printing apparatus according to claim 4, wherein said driving means drives said variable roller spacing means, paper size detecting means detects a paper size, and an output signal from said paper size detecting means. A control unit for controlling the driving unit so as to change the interval between the pressing rollers in the paper width direction. 6. A multi-color printing apparatus according to claim 1, wherein said paper pressing means blows the paper on said impression cylinder at an outlet side of a region between said printing drum and said impression cylinder by blowing air. A multicolor printing apparatus, characterized in that it is a blowing means for pressing against the outer peripheral surface of the printing cylinder. 7. A printing drum, comprising: a plurality of printing drums; and a printing pressure cylinder having a holding means for holding a leading end of a sheet, wherein the printing drums are arranged around the printing pressure cylinder. A multi-color printing apparatus capable of performing multi-color printing by pressing the printing drum relative to the printing impression cylinder, wherein an exit side of a sandwiching region between each printing drum and the printing pressure cylinder and each of the adjacent printing drums And a blower for pressing the paper on the impression cylinder to the impression cylinder at both the downstream side of the printing drum and the entrance side of the sandwiching area between the impression cylinder. Multicolor printing device. 8. The multicolor printing apparatus according to claim 6, wherein said blowing means includes a blowing source for generating an air flow, and an air flow from said blowing source for each of said printing drum and said impression cylinder. A multi-color member having a wind guide member that forms a flow path for guiding paper to the sandwiching region exit side or both the sandwiching region exit side and the sandwiching region entrance side to press the paper against the impression pressure cylinder. Printing device. 9. The multicolor printing apparatus according to claim 8, wherein the air guide member is connected to an upstream end of a paper transport path located near an upstream print drum among the adjacent print drums. Multicolor printing, wherein a flow path for blowing an air flow from the air blowing source is formed at a downstream end of the sheet transport path located near a downstream printing drum among the adjacent printing drums. apparatus. 10. A multi-color printing apparatus according to claim 8, wherein a paper information input means for inputting paper information, and an operation of said air supply source is controlled according to the input information from said paper information input means. A multicolor printing apparatus, comprising: a control unit. 11. A multi-color printing apparatus according to claim 10, further comprising an air volume setting means connected to said control means, wherein said control means operates said air supply source in response to a signal from said air volume setting means. Is controlled separately from the input information from the paper information input means. 12. A multi-color printing apparatus according to claim 10, wherein said paper information input means outputs a signal corresponding to a type of said paper to said control means, and said paper information input means outputs a signal according to a size of said paper. And a paper size setting means for outputting the output signal to the control means. 13. The multicolor printing apparatus according to claim 2, wherein a sheet on the printing cylinder is formed by printing the paper on the printing cylinder at an exit side of a sandwiching area between each printing drum and the printing cylinder. A multicolor printing apparatus comprising: a blower for pressing against an outer peripheral surface of an impression cylinder.