JP3553226B2 - Double-sided printing device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a double-sided printing apparatus capable of printing on both sides of a printing sheet, and more particularly to a stencil printing type double-sided printing apparatus that performs printing using a stencil printing sheet on which a perforated image is formed.
[0002]
[Prior art]
The stencil sheet for stencil printing is wound around the outer circumference of the printing drum, and the printing paper is pressed against the stencil printing paper by a press roller provided outside the printing drum, and the ink in the printing drum is transferred onto the printing paper. 2. Description of the Related Art A stencil printing apparatus that performs printing by printing is known.
[0003]
FIG. 5 schematically shows the structure of such a stencil printing machine.
A printing drum 100 is arranged at the center of the printing press. On the right side of the printing drum 100, there is a plate making means 101 having a thermal head, a platen roller, a roll-shaped stencil sheet, and a cutter. On the left side of the printing drum 100, there is a plate discharging means 102 for storing used stencil sheet. Above the printing drum 100, there is a document reading means 103 for sequentially reading the image information of the document. On the lower left side of the printing drum 100, there is a paper feeding unit 104 for sequentially feeding a stack of paper stacked on a paper feeding table from the top sheet. Below the printing drum 100 is a printing means 105 having a press roller for pressing the printing drum 100. Below the plate making means 101, there are a separating claw for separating printed paper from the printing drum 100 and a peeling means 106 provided with an air blow means. On the lower right side of the print drum 100, there is a discharge stacker 107 for storing printed sheets peeled off from the print drum 100.
[0004]
In the stencil printing machine, used stencil printing paper is stored and discarded in a stencil printing paper discharging means 102. Based on the document information read by the document reading means 103, a perforated image is formed on the stencil printing paper by the thermal head. The leading end of the stencil printing paper is fixed to the printing drum 100 by clamping means. After the stencil making is completed, the printing drum 100 is rotated to wind the stencil printing stencil around the printing drum 100. Thereafter, the paper is sent out from the paper supply unit 104, and printing is performed on the paper with the paper interposed between the rotating printing drum 100 and the press roller of the printing unit 105.
[0005]
[Problems to be solved by the invention]
In the above-described conventional stencil printing apparatus, printing can be performed only on one side of printing paper. When printing is to be performed on both sides of the printing paper using this stencil printing apparatus, the operator takes out the printing paper on which printing on one side has been completed from the paper output stacker 107, turns it over, and feeds the paper in FIG. Placed again in the means 104. After the plate making is performed again, it is necessary to print the other side.
[0006]
Therefore, it takes time and effort for the operator to reset the printing paper from the paper discharge stacker 107 to the paper feeding means 104, and in that case, there is a trouble that the user has to check the vertical direction of the paper.
[0007]
In addition, since printing on the opposite side is performed after printing on one side is completed, it is necessary to perform stencil making in two steps in the process of completing one printed material, which is a time loss.
[0008]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION An object of the present invention is to provide a double-sided printing apparatus capable of printing on both sides of a printing paper in one plate making process and printing process.
[0009]
The double-sided printing apparatus according to claim 1, comprising a first plate and a second plate, wherein the printing drum is rotatable around its own central axis, and near the printing drum at a predetermined timing. Feeding means for supplying the printing paper to the printing drum; pressing the first side of the printing paper supplied by the feeding means near the printing drum against a first plate of the printing drum; A first pressing means for forming the first print image on the first surface of the printing paper, and a printing paper on which the first print image is printed on the first surface is a surface opposite to the first surface. Printing paper reversing means for reversing the second surface so as to face the printing drum, and pressing the second surface of the printing paper inverted by the printing paper reversing means against a second plate on the printing drum Forming a second print image by the second plate on the second side of the printing paper Characterized by comprising a means.
[0010]
A double-sided printing apparatus according to claim 2 has a substantially cylindrical peripheral wall that is at least partially ink-permeable, and forms a first plate-making image and a second image based on the first image. A stencil sheet for stencil printing, on which a second stencil image based on each of the stencil images is perforated, is wound around the outer peripheral surface of the peripheral wall, and is provided inside the print drum. An ink supply unit for supplying ink to the inner peripheral surface of the peripheral wall, a paper supply unit for supplying print paper to the vicinity of the print drum at a predetermined timing, and the paper supply unit supplying the print paper to the vicinity of the print drum. The first surface of the printing paper is pressed against the printing drum, and the ink supplied to the inner peripheral surface of the printing drum is transferred to the first surface of the printing paper via the first platemaking image of the stencil printing paper. To form a first print image Pressing means, and a printing sheet on which a first plate-making image is printed on a first surface by the first pressing means, and a second surface opposite to the first surface is provided on the printing drum. A printing paper reversing means for reversing the printing paper so as to face to the side, and pressing a second surface of the printing paper reversed by the printing paper reversing means against the printing drum, and discharging the ink supplied to the inner peripheral surface of the printing drum. And a second pressing means for transferring the stencil printing base paper to the second surface of the printing paper via the second stencil image to form a second printing image.
[0011]
In the double-sided printing apparatus according to the third aspect, in the double-sided printing apparatus according to the second aspect, the printing paper reversing unit moves the printing paper on which the first print image is formed in a direction away from the printing drum. A first transport unit for transporting the printing paper toward the printing drum, and a biasing unit for biasing the printing paper transported by the first transport unit toward the printing drum; and the printing biased by the biasing unit. And a second transport unit that transports the paper toward the printing drum with a second surface facing the printing drum.
[0012]
A double-sided printing apparatus according to a fourth aspect of the present invention is the double-sided printing apparatus according to the third aspect, wherein a gate that regulates a transport path of the printing paper is provided between the first transport unit and the second transport unit. Is provided rotatably.
[0013]
The double-sided printing apparatus according to claim 5, wherein in the double-sided printing apparatus according to claim 2, the ink supply unit corresponds to the first and second pressing units with a peripheral wall of the printing drum interposed therebetween. , Respectively.
[0014]
According to the above-described means, an image can be printed on both sides of the printing paper by arranging the printing paper in the paper feeding means and performing one plate making process and one continuous printing process thereafter. . Therefore, there is no need for the operator to perform a complicated operation such as arranging the printing paper discharged in a state where one side is printed again in the paper feeding means as in the related art. Further, since double-sided printing can be performed by one plate making and printing, plate making and printing time can be shortened as compared with printing both sides by repeating plate making and printing twice.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a side sectional view showing a stencil printing apparatus 1 as a double-sided printing apparatus according to an embodiment of the present invention. A printing drum 2 is arranged at a substantially central portion of the stencil printing apparatus 1. The printing drum 2 has a substantially cylindrical peripheral wall at least partially permeable to ink, and is rotatable about its own central axis. In FIG. 1, it rotates in a counterclockwise direction indicated by an arrow A with respect to a central axis perpendicular to the paper surface. A stencil sheet S is wound around the outer peripheral surface of the peripheral wall. On the stencil sheet S, a first plate-making image 3 as a first plate and a second plate-making image 4 as a second plate are arranged at predetermined intervals along the circumferential direction of the printing drum 2. It is perforated.
[0016]
A clamp base 5 is provided on a part of the outer peripheral surface of the peripheral wall of the printing drum 2 in parallel with the central axis. A clamp 6 for locking one end of the stencil sheet S is rotatably attached to the clamp base 5.
[0017]
As shown in FIG. 2, two sets of ink supply means 7 and 8 for supplying ink to the inner peripheral surface of the peripheral wall are provided inside the print drum 2. Each of the ink supply means 7 and 8 includes a rotatable ink supply roller 7a, 8a in contact with the peripheral wall of the print drum 2, and a doctor roller rotatably arranged in parallel with a slight gap between the ink supply rollers 7a, 8a. 7b and 8b. The ink supply rollers 7a and 8a rotate in the directions of arrows D and F, respectively, as the print drum 2 rotates in the direction of arrow A. At this time, the printing ink is dropped from the distributor 9 between the ink supply rollers 7a, 8a and the doctor rollers 7b, 8b, and the ink vortex 10, 10 is formed between the doctor rollers 7b, 8b by the rotation of the ink supply rollers 7a, 8a. It is formed. The printing ink is supplied to the inner peripheral surface of the peripheral wall of the print drum 2 from the gap between the ink supply rollers 7a and 8a and the doctor rollers 7b and 8b, along the surfaces of the ink supply rollers 7a and 8a. As a result, an appropriate amount of printing ink is always supplied to the inner peripheral surface of the peripheral wall of the printing drum 2 during printing.
[0018]
On the right side of the printing drum 2 is a plate making section. The stencil making unit 11 stores an unused roll-shaped stencil sheet S for use. On the stencil sheet S, a desired image is pierced by a piercing section 12 composed of a combination of a thermal head 12a and a platen roller 12b. The stencil sheet S on which the image has been perforated is transported by the transport rollers 13. The stencil sheet S is cut by the cutter 14 when it has been wound around the outer peripheral surface of the printing drum 2 once.
[0019]
On the left side of the printing drum 2, there is a stencil discharging unit 15 that separates the stencil sheet S for which printing has been completed from the printing drum 2 and stores it.
[0020]
At the lower left side of the printing drum 2, a paper feeding unit 16 that supplies the printing paper P to the vicinity of the printing drum 2 at a predetermined timing is provided. The paper supply unit 16 includes a paper supply table 16a on which a large number of printing papers P are placed and ascends and descends as necessary, and a primary paper supply roller 16b for discharging the printing paper P on the paper supply table 16a. I have.
[0021]
A primary press roller 17 as a first pressing unit is provided at a position below the left side of the printing drum 2 and closer to the printing drum 2 than the sheet feeding unit 16. The primary press roller 17 is rotatable and can move toward or away from the printing drum 2. The primary press roller 17 can press the first surface of the printing paper P against the printing drum 2 when the paper supply unit 16 supplies the printing paper P near the printing drum 2. At this time, the position of the printing drum 2 in the rotation direction is appropriately adjusted. Accordingly, the first surface of the printing paper P is pressed against the first plate-making image 3 of the stencil sheet S wound on the printing drum 2, and the first printing image based on the first plate-making image 3 is formed on the printing paper P. Printed on the first side.
[0022]
The position where the primary press roller 17 presses the printing drum 2 corresponds to the position of one ink supply roller 7a of the two sets of ink supply means 7 and 8 provided in the printing drum 2. Accordingly, since an appropriate amount of ink is always supplied to the inner peripheral surface side of the printing drum 2 on which the primary press roller 17 has pressed the printing paper P, appropriate printing is performed on the first surface of the printing paper P. Is performed.
[0023]
A primary separation claw 18 is movably provided near the primary press roller 17. The primary separation claw 18 is printed by being pressed against the printing drum 2 by the primary press roller 17, and has a function of peeling the leading end of the printing paper P stuck to the printing drum 2 from the printing drum 2.
[0024]
Below the printing drum 2, a printing paper reversal for reversing the printing paper P on which the first print image is printed on the first surface, so that the second surface faces the printing drum 2. Means 19 are provided. The printing paper reversing means 19 has a first transport means 20. The first transport unit 20 transports the printing paper P on which printing has been performed on the first surface and which has been peeled off from the printing drum 2 by the primary separation claws 18, below the printing drum 2.
[0025]
The first transport means 20 is located on the lower left side of the printing drum 2 and has a transport belt composed of a plurality of pulleys and an endless belt wound around the pulleys. Although not shown, the transport belt is provided with a suction means such as a rotating fan, so that the printing paper P can be reliably transported by being sucked and held on the endless belt. According to this example, since the printing paper P is sucked from the back side of the transport belt by the negative pressure, an appropriate frictional force is generated between the transport belt and the printing paper P for transport. However, in order to securely hold and convey the printing paper P, a conveyance roller is provided in contact with the conveyance belt on the printing drum 2 side in place of or together with the suction means, and the printing paper P is conveyed by the conveyance belt and the conveyance rollers. You may pinch. By such means, a frictional force suitable for conveyance is obtained between the conveyance belt and the printing paper P.
[0026]
The printing paper reversing means 19 has a biasing means 21 below the printing drum 2. The urging means 21 has a guide portion 21a for regulating the position of the printing paper P, and an elastic member 21b interposed in the guide portion 21a and contracting by the entered printing paper P. The printing paper P, which is printed on one side and conveyed by the first conveying means 20, enters the urging means 21 to retract the elastic member 21b. The contracted elastic member 21b applies a biasing force toward the printing drum 2 to the printing paper P. Therefore, when the printing paper P is separated from the first transporting means 20 and becomes free, the printing paper P becomes elastic by the elastic member 21b. It jumps out toward the printing drum 2 by force.
[0027]
The printing paper reversing unit 19 has a second transport unit 22. The second transporting unit 22 is located on the lower right side of the printing drum 2, and is installed at a position symmetrical to the first transporting unit 20 with the printing paper reversing unit 19 interposed therebetween. The second transport unit 22 transports the printing paper P that has jumped out of the printing paper reversing unit 19 toward the printing drum 2 with the second surface facing the printing drum 2.
[0028]
The second transport means 22 has a transport belt including a plurality of pulleys and an endless belt wound around the pulleys. Although not shown, the transport belt is provided with a suction means such as a rotating fan, so that the printing paper P can be reliably transported by being sucked and held on the endless belt. According to this example, since the printing paper P is sucked from the back side of the transport belt by the negative pressure, an appropriate frictional force is generated between the transport belt and the printing paper P for transport. However, in order to securely hold and convey the printing paper P, a conveyance roller is provided in contact with the conveyance belt on the printing drum 2 side in place of or together with the suction means, and the printing paper P is conveyed by the conveyance belt and the conveyance rollers. You may pinch. By such means, a frictional force suitable for conveyance is obtained between the conveyance belt and the printing paper P.
[0029]
At a position between the printing drum 2 and the urging means 21 and between the first and second conveying means 20 and 22, a gate 23 for regulating a conveying path of the printing paper P is rotatably provided. ing. The gate 23 is selectively set to a first position shown in FIG. 1 and a second position shown in FIG. 3 in synchronization with the printing operation. The first position is selected when the printing paper P on which the first surface is printed is conveyed by the first conveying means 20 away from the printing drum 2 and guided to the printing paper reversing means 19. The second position is selected when the second conveying unit 22 conveys the printing paper P jumped out of the printing paper reversing unit 19 to the printing drum 2.
[0030]
A secondary press roller 24 as a second pressing unit is provided at a position on the lower right side of the printing drum 2 and adjacent to the second conveying unit 22. The secondary press roller 24 is rotatable and can move toward or away from the printing drum 2. The secondary press roller 24 can press the second surface of the print paper P against the print drum 2 when the second transport means 22 has transported the print paper P to the vicinity of the print drum 2. At this time, the position of the printing drum 2 in the rotation direction is appropriately adjusted. Therefore, the second surface of the printing paper P is pressed against the second plate-making image 4 of the stencil sheet S wound around the printing drum 2, and the second printing image based on the second plate-making image 4 is formed on the printing paper P. Printed on the second side.
[0031]
The position where the secondary press roller 24 presses the print drum 2 corresponds to the position of the other ink supply roller 8a of the two sets of ink supply means 7 and 8 provided in the print drum 2. Accordingly, since an appropriate amount of ink is always supplied to the inner peripheral surface side of the printing drum 2 on which the secondary press roller 24 has pressed the printing paper P, an appropriate amount of ink is also supplied to the second surface of the printing paper P. Printing is performed.
[0032]
A secondary separation claw 25 is movably provided near the secondary press roller 24. The secondary separation claw 25 is printed by being pressed against the print drum 2 by the secondary press roller 24, and has a function of peeling the leading end of the printing paper P stuck to the print drum 2 from the print drum 2.
[0033]
At the lower right side of the printing drum 2, a paper discharging means 26 for discharging the printing paper P on which both sides are printed is provided. The paper discharging unit 26 has a transport unit 26a that transports the printing paper P held by the suction mechanism by the belt transport mechanism, and a paper discharging unit 26b that stacks the printing paper P transported by the transporting unit 26a.
[0034]
The operation of the above configuration will be described. In this example, printing is performed on the front surface and the back surface of one print sheet P, respectively. An image to be printed on the front side is a first image, and an image to be printed on the back side is a second image. When performing stencil making with the stencil printing machine 1, first, the first and second images are read by a document reading device (not shown) to obtain image information, and based on the image information, the stencil making unit 11 is used. Is driven. Thereby, the first stencil image 3 based on the first image and the second stencil image 4 based on the second image are provided on the unused stencil sheet S in the stencil making section 11. The holes are punched at predetermined intervals in the transport direction of the printing paper S.
[0035]
The stencil sheet S on which both stencil images are perforated is conveyed from the stencil unit 11 to the printing drum 2. The leading end of the stencil sheet S is fixed between the clamp base 5 and the clamp 6.
[0036]
Next, the printing drum 2 rotates in the direction of arrow A, and the stencil sheet S on which an image is perforated is wound around the outer peripheral surface of the peripheral wall of the printing drum 2. After the stencil sheet S is wound once around the outer peripheral surface of the printing drum 2, the cutter 14 of the plate making section 11 cuts the stencil sheet S.
[0037]
Therefore, as shown in FIG. 2, a first plate-making image 3 based on an image of a document to be printed on the surface of the printing paper P (hereinafter, referred to as an image a) is provided on the surface of the printing drum 2 at the time of printing. Second plate making images 4 based on an image of a document to be printed on the back side of P (hereinafter, referred to as image b) are arranged at a constant interval in the rotation direction of the printing drum 2.
[0038]
When printing is performed, the printing paper P is placed on the paper feed table 16a, and the switch for starting printing is turned on. Power is transmitted from a power motor (not shown), and the primary paper feed roller 16 b rotates to convey the printing paper P to the vicinity of the printing drum 2. The printing drum 2 is rotated in the direction of arrow A by the action of the power motor in time with the conveyance of the printing paper P. The printing paper P is printed on the printing drum 2 and the primary press roller 17 at the same time that the first plate-making image 3 of the stencil sheet S wound on the outer peripheral surface of the printing drum 2 reaches the vicinity of the primary press roller 17. Conveyed during.
[0039]
The primary press roller 17 presses the printing paper P against the printing drum 2 in synchronization with the conveyance of the printing paper P in order to print the image a on the surface of the printing paper P. That is, in FIG. 1, the primary press roller 17 moves in the direction of arrow B, and the surface of the supplied printing paper P is pressed against the first plate-making image 3 of the stencil printing paper S wound on the printing drum 2, and the printing drum The printing ink in 2 is transferred to the surface of the printing paper P, and the image a is printed on the surface.
[0040]
When printing of the image a is completed, the primary press roller 17 separates from the printing drum 2. The printing paper P is separated from the printing drum 2 by the primary separation claws 18 and is sent to the printing paper reversing means 19 as the printing drum 2 rotates. At this time, the tip of the gate 23 is directed rightward, and the printing paper P on which printing by the primary press roller 17 has been completed is easy to enter. The printing paper P sent to the printing paper reversing means 19 is sucked and held by the transporting belt rotating in the direction of arrow G in the first transporting means 20, and is transported toward the urging means 21. The printing paper P is conveyed downward along the guide portion 21a material of the urging means 21, and pushes down the elastic member 21b.
[0041]
Next, as shown in FIG. 3, when the leading end of the gate 23 faces to the left and the holding of the printing paper P by the first transporting means 20 is released and the transporting by the first transporting means 20 is stopped, the printing paper P Project out of the printing paper reversing means 19 by the repulsive force of the elastic member 21b.
[0042]
The printing paper P is sucked and held on the transport belt of the second transport unit 22 by the suction unit. The printing paper P is conveyed to the vicinity of the secondary press roller 24 with the back surface facing the printing drum 2 by moving the conveyance belt of the second conveyance means 22 in the direction of arrow H as shown in FIG. Is done. At this time, the second stencil image 4 of the stencil sheet S wound around the printing drum 2 has been rotated to a position close to the secondary press roller 24, and the printing paper P is , The secondary press roller 24 presses the printing paper P in the direction of the arrow C. As a result, the back surface of the printing paper P is pressed against the second plate-making image 4 of the stencil printing paper S wound around the printing drum 2, and the printing ink in the printing drum 2 is transferred to the back surface of the printing paper P, The image b is printed on the back surface.
[0043]
In this case, the secondary press roller 24 contacts the surface of the printing paper P. Since the image a is printed on the surface of the printing paper P, it is preferable that the printing on this front side is sufficiently dried. However, even if the image printed on the surface of the printing paper P is not sufficiently dried, the transport belt and the secondary press roller 24 may have a structure and / or material that does not transfer the printing ink printed on the printing paper P. I just need.
[0044]
Next, the printing paper P on which printing is performed on both the back surface and the front surface is separated from the printing drum 2 by the secondary separation claw 25, held by the suction mechanism, transferred by the transfer unit 26a, and transferred to the discharge unit 26b. Is stored.
[0045]
After the printing is completed, the leading end of the used and unnecessary stencil sheet S is released from the printing drum 2 by the rotation of the clamp 6 and the separation from the clamp base 5. In this state, by rotating the printing drum 2 in the direction of the arrow A, the leading end of the stencil sheet S is drawn into the plate discharging section 15, peeled off from the printing drum 2, and stored in the plate discharging section 15.
[0046]
As described above, when printing is performed on both sides of the printing paper P using the stencil printing apparatus 1 of the present embodiment, time is required for reversing the printing paper P in synchronization with the rotation of the printing drum 2. Become. For this reason, a predetermined interval in the circumferential direction must be provided between the two stencil images 3 and 4 of the stencil sheet S. In the example shown in FIG. 2, the first stencil image 3 to be printed first is formed on the leading end side of the stencil sheet S in the counterclockwise rotation direction in the drawing, and the stencil image is formed. On the side of the rear end of the printing base paper S, a second plate-making image 4 to be printed later is formed. Accordingly, the stencil sheet S has an area where no stencil image is formed between the two stencil images 3 and 4, and this area is defined by the distance between the two stencil images 3 and 4 provided in the rotation direction of the printing drum 2. It has become. The size of both plate making images is restricted due to the portion where the plate making images cannot be provided.
[0047]
However, in the example shown in FIG. 4, in the rotation direction of the printing drum 2, a second stencil image 4 to be printed later is formed on the side of the leading end of the stencil sheet S, and the stencil sheet S The first plate-making image 3 to be printed first is formed on the rear end side. In this way, the interval between the two images 3 and 4 continuously printed on the front and back of one sheet of printing paper P depends on the portions of the clamp base 5 and the clamp 6 to which the leading end of the stencil sheet S is fixed. Will be hit. In this manner, it is not necessary to provide a large space between the first plate-making image 3 and the second plate-making image 4 in one stencil sheet S as shown in FIG. Accordingly, it is possible to form a larger stencil image, and it is possible to effectively use the stencil-making area of the stencil sheet S and reduce the cost of consumables.
[0048]
In the above-described embodiment, the stencil printing apparatus 1 is illustrated as an example of the two-sided printing apparatus. However, the configuration for the two-sided printing described above can be applied to a printing apparatus having other principles. For example, the present invention can be applied to offset printing and the like.
[0049]
【The invention's effect】
According to the double-sided printing apparatus of the present invention, it is possible to print an image on both sides of the printing paper P by one plate making process and one subsequent printing process. Therefore, unlike a case where two-sided printing is performed using a conventional printing apparatus, there is no need for a user of the printing apparatus to re-arrange the printing paper once discharged on the paper supply side. Further, since double-sided printing can be performed in a single plate-making process and printing process, the plate-making process and the printing process are performed twice, respectively, so that plate-making and printing time can be reduced as compared with printing on both sides.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of a stencil printing apparatus according to an embodiment of the present invention.
FIG. 2 is a sectional view of a printing drum of the stencil printing machine of FIG.
FIG. 3 is a cross-sectional view illustrating an example of a stencil printing apparatus according to the embodiment of the present invention.
FIG. 4 is a cross-sectional view illustrating another example of a use form of the printing drum according to the embodiment of the present invention.
FIG. 5 is a sectional view of a conventional printing apparatus.
[Explanation of symbols]
1 Stencil printing machine as double-sided printing machine
2 Printing drum
3 First platemaking image as first plate
4 Second plate-making image as second plate
7, 8 ink supply means
16 Paper feeding means
17 Primary press roller as first pressing means
19 Printing paper reversing means
20 First transport means
21 biasing means
22 Second transport means
23 gate
24 Secondary press roller as second pressing means

Claims (5)

A print drum having a first plate and a second plate, the print drum being rotatable about its own central axis;
Paper supply means for supplying print paper to the vicinity of the print drum at a predetermined timing;
The paper feeding unit presses a first surface of the printing paper supplied near the printing drum against a first plate of the printing drum, and prints a first print image by the first printing plate on the first surface of the printing paper. A first pressing means formed on
Printing paper reversing means for reversing the printing paper on which the first print image is printed on the first surface so that the second surface opposite to the first surface faces the printing drum; ,
The second surface of the printing paper inverted by the printing paper reversing means is pressed against a second plate on the printing drum, and a second print image by the second printing plate is formed on the second surface of the printing paper. Second pressing means;
A double-sided printing apparatus comprising: A stencil having a substantially cylindrical peripheral wall at least partially permeable to ink, and perforated with a first stencil image based on the first image and a second stencil image based on the second image, respectively A printing drum, on which the printing base paper is wound around the outer peripheral surface of the peripheral wall, and is rotatable around its own central axis,
An ink supply unit that is provided inside the printing drum and supplies ink to an inner peripheral surface of the peripheral wall;
Paper supply means for supplying print paper to the vicinity of the print drum at a predetermined timing;
The paper supply unit presses a first surface of the printing paper supplied in the vicinity of the printing drum against the printing drum, and applies ink supplied to an inner peripheral surface of the printing drum to a first plate making of the stencil printing base paper. First pressing means for transferring to the first surface of the printing paper via the image to form a first printed image;
The printing paper on which the first plate-making image is printed on the first surface by the first pressing means is moved so that the second surface, which is the surface opposite to the first surface, faces the printing drum. Printing paper reversing means for reversing,
The second surface of the printing paper inverted by the printing paper inversion means is pressed against the printing drum, and the ink supplied to the inner peripheral surface of the printing drum is passed through a second plate-making image of the stencil printing base paper. Second pressing means for transferring to a second surface of the printing paper to form a second print image;
A double-sided printing apparatus comprising: A first conveyance unit configured to convey the printing paper on which a first print image is formed in a direction away from the printing drum, and the printing medium conveyed by the first conveyance unit; Urging means for urging the paper toward the printing drum; and conveying the printing paper urged by the urging means toward the printing drum with a second surface facing the printing drum. The double-sided printing apparatus according to claim 2, further comprising a second transport unit. 4. The double-sided printing apparatus according to claim 3, wherein a gate that regulates a conveyance path of the printing paper is rotatably provided between the first conveyance unit and the second conveyance unit. The two-sided printing apparatus according to claim 2, wherein the ink supply unit is provided at a position corresponding to the first and second pressing units with the peripheral wall of the printing drum interposed therebetween.

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