JP4813825B2 - Duplex printing device - Google Patents

Description

  The present invention relates to a printing apparatus such as a stencil printing apparatus and an offset printing apparatus that perform printing by winding a master on an outer peripheral surface of a plate cylinder, and more particularly, cleaning of a pressing unit used in a double-sided printing apparatus that performs printing on both sides of a sheet. Relates to the device.

  Conventionally, digital thermal stencil printing is known as a simple printing method. A stencil printing apparatus for performing stencil printing has a thermal head in which fine heating elements are arranged in a row in contact with the master, and conveys the master while energizing the heating elements in a pulsed manner, thereby moving the master according to image information. After heating and melting and punching, this master is wound around the outer peripheral surface of a porous cylindrical plate cylinder, and then the outer surface of the plate cylinder is pressed by a pressing means such as a press roller through a sheet of paper. A printed image is obtained by transferring the transmitted ink to paper.

  In this stencil printing, in recent years, double-sided printing, in which printing is performed on both sides of a sheet, has been frequently performed for the purpose of reducing paper consumption and document storage space. This double-sided printing is a conventional method in which the paper stacked on the paper feed unit is passed through the printing unit, printed on one side, then turned over, and again passed through the printing unit to print on the other side. Although a double-sided printed material has been obtained, there is a problem that it is troublesome to set the paper once ejected to the paper feeding unit or to align the paper after single-sided printing.

  Therefore, using a divided master-making master in which the first and second master-making images are arranged in two directions in the direction of rotation of the printing cylinder, one master-making image is formed on the surface of the first sheet fed from the paper feeding unit. After the image is printed, this sheet is guided to the refeed tray (auxiliary tray), and after making one plate-making image on the surface of the second sheet fed from the sheet feeding section, this sheet is fed to the refeed tray. The first sheet from the sheet re-feeding tray, printing the other plate-making image on the back side, and discharging this sheet to the sheet discharging tray. For example, “Patent Document 1” discloses a double-sided printing apparatus that obtains a double-sided printed material in one step.

  In the case of performing one-step double-sided printing as described above in a printing apparatus such as a stencil printing apparatus or an offset printing apparatus using a master as in the case of a stencil printing apparatus, one side of a sheet is pressed by pressing means such as a press roller against the plate cylinder. The front surface is pressed to form a front image, and immediately after that, the other surface of the paper is pressed against the plate cylinder by the pressing means to form the back image, so that the undried ink of the front image is transferred to the pressing means. As a result, there arises a problem that the back side of the paper is stained with ink during the next printing.

  As a countermeasure against ink transfer stains on the back side of paper during double-sided printing, there is a technology that reduces the amount of ink adhering to the peripheral surface of the press roller by providing multiple fine irregularities on the peripheral surface of the press roller that directly contacts the printing surface. Although this technique has been proposed, since the ability to prevent ink transfer stains is small and insufficient, a technique that uses a cleaning roller that is pressed against the peripheral surface of the press roller and that is rotationally driven with a speed difference is disclosed in, for example, “Patent” Document 2 ”.

JP 2003-200355 A JP 2004-338234 A

  However, in the technique disclosed in “Patent Document 2”, since the cleaning roller that is rotationally driven with a speed difference is pressed against the press roller, the speed difference with the cleaning roller becomes a load and the rotational peripheral speed of the press roller is the plate speed. Since the rotation speed is slower than the rotational peripheral speed of the cylinder, when the press roller comes into contact with the master on the outer peripheral surface of the plate cylinder, a load is applied to the master due to the difference in the rotational peripheral speed between the plate cylinder and the press roller. There is a problem that such a problem occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a double-sided printing apparatus capable of suppressing ink transfer stains at the time of one-step double-sided printing with high accuracy without imposing a load on the master.

The invention according to claim 1 includes a plate cylinder around which the master is wound, and a press roller disposed so as to be able to come in contact with and separate from the plate cylinder which presses the paper against the master. In a double-sided printing apparatus that performs a back surface printing step of printing a back surface image on the other surface of the paper after performing a surface printing step of printing a surface image on the surface of the paper, a back printing press roller used in the back surface printing step is thereby have a plurality of fine irregularities on its periphery, in contact with the peripheral surface of the rear surface printing press roller have a brush roller is driven to rotate, the back printing press roller presses the sheet to the master And a contact member that rotates following the plate cylinder and is driven to rotate at the same peripheral speed as the driven rotation when separated from the master and contacts the brush roller. printing With the contact direction of the brush roller with respect to the press roller in contact with the brush roller from a direction perpendicular, characterized in that it is elastically deformable upon contact with the brush roller.

According to a second aspect of the present invention, in the double-sided printing apparatus according to the first aspect, the brush roller is formed by implanting a brush made of a fibrous member on a base material .

According to a third aspect of the invention, the double-sided printing apparatus according to claim 2, wherein a further said brush 70 to 100 denier / 5 filaments, and wherein that the planted bristle density is 2500 to 3000 present / inch ² To do.

According to a fourth aspect of the present invention, in the double-sided printing apparatus according to any one of the first to third aspects , the contact pressure of the brush roller with respect to the press roller for backside printing is 400 gf or less. .

According to a fifth aspect of the present invention, in the double-sided printing apparatus according to any one of the first to fourth aspects, the brush roller is detachable from the apparatus main body .

According to a sixth aspect of the present invention, in the double-sided printing apparatus according to any one of the first to fifth aspects, the first plate cylinder disposed as opposed to one surface of the sheet as the plate cylinder; A second plate cylinder disposed downstream of the first plate cylinder in the sheet conveying direction and opposite to the other surface of the sheet; After having performed the surface printing process with the first plate cylinder and the first press roller, the first press roller and the second press roller that can freely contact and separate from the second plate cylinder, A double-sided printing apparatus that conveys the surface-printed paper and performs the backside printing process using a second plate cylinder and a second press roller, wherein the second press roller functions as the backside printing press roller. It is characterized by.

According to a seventh aspect of the present invention, in the double-sided printing apparatus according to any one of the first to fifth aspects , the divided pre- printed image further includes a first plate-making image and a second plate-making image in the length direction as the master. After the master is wound around the plate cylinder and the sheet is pressed against the plate cylinder by the press roller, the surface image is printed on one surface of the sheet and the surface printing process is performed, and then the surface A double-sided printing apparatus that performs the backside printing step of printing the backside image on an unprinted side of the frontside printed paper by refeeding the printed paper and pressing the plate cylinder with the press roller; The press roller functions as the press roller for back side printing .

  According to the present invention, by using the brush roller that rotates in contact with the peripheral surface of the press roller for backside printing having a plurality of fine irregularities on the peripheral surface, ink smears on the peripheral surface of the press roller for backside printing. Can effectively prevent the remaining image from being smeared, and the master roll wound on the outer peripheral surface of the plate cylinder when contacting the press roller for printing on the back surface is not subjected to a load. A good image can be obtained by preventing the occurrence of distortion.

  FIG. 1 shows a duplex printing apparatus employing the first embodiment of the present invention. In the figure, a duplex printing apparatus 1 includes a plate cylinder 2 as a first plate cylinder, a plate cylinder 3 as a second plate cylinder, a press roller 4 as a first press roller, and a press as a second press roller. A roller 5, a paper feed tray 6, a paper feed roller 7, a registration roller pair 8, a paper transport unit 9, and a paper discharge tray 10 are included.

  The plate cylinder 2 is rotatably supported by an apparatus main body (not shown) and is driven to rotate by a plate cylinder driving means (not shown). The plate cylinder 2 has a clamper 11 that can be freely opened and closed on its outer peripheral surface, and a master 12 that has been made by a plate making apparatus (not shown) is wound on the outer peripheral surface of the plate cylinder 2. On the master 12, a plate-making image corresponding to the surface image printed on the surface of the paper P is formed. An ink supply means (not shown) for supplying ink to the inner peripheral surface of the plate cylinder 2 is disposed inside the plate cylinder 2.

  The plate cylinder 3 is also rotatably supported by an apparatus main body (not shown), and is driven to rotate in the reverse direction in synchronization with the plate cylinder 2 by a plate cylinder driving means (not shown). The plate cylinder 3 has a freely openable and closable clamper 13 on its outer peripheral surface, and a master 14 having been made by a plate making apparatus (not shown) is wound on the outer peripheral surface of the plate cylinder 3. A master-making image corresponding to the back image printed on the back surface of the paper P is formed on the master 14. An ink supply means (not shown) that supplies ink to the inner peripheral surface of the plate cylinder 3 is also provided inside the plate cylinder 3.

  A press roller 4 is disposed below the plate cylinder 2. Both ends of the press roller 4 made of an elastic body having water repellency such as fluororesin are rotatably supported by an arm member (not shown), and the arm member (not shown) is swung by a swinging unit (not shown). As a result, the press roller 4 selectively occupies the press contact position shown in FIG. 1 where the peripheral surface is pressed against the master 12 on the plate cylinder 2 and the spaced position where the peripheral surface is separated from the plate cylinder 2.

  A press roller 5 is disposed above the plate cylinder 3. As shown in FIG. 2, the diameter of the press roller 5 used as the press roller for printing on the back surface is wound by winding a resin sheet 17 having a glass bead 16 bonded on the surface of a cylindrical elastic body 15. In the form, it is configured to be 60 mm, and a plurality of fine irregularities are formed on the surface thereof. As shown in FIG. 3, the press roller 5 is rotatably supported at both ends of a support shaft 5a by bearings 20 and 21 provided on a pair of arm members 18 and 19, and each arm member 18 and 19 is illustrated. It is rocked by the rocking means that does not. As a result, the press roller 5 selectively occupies the press contact position shown in FIG. 1 where the peripheral surface is pressed against the master 14 on the plate cylinder 3 and the spaced position where the peripheral surface is separated from the plate cylinder 3. A timing pulley 22 is fixed to the end of the support shaft 5a supported by the arm member 18 by a pin 23. A rotational driving force from a driving means (not shown) is applied to the timing pulley 22 via a timing belt (not shown). Communicated. The driving means (not shown) is operated only in a state where the press roller 5 occupies the separation position. With this configuration, when the press roller 5 occupies the pressure contact position, the press roller 5 is driven and rotated by the rotational force of the plate cylinder 3 to set the separation position. When occupied, it is rotationally driven by the driving means (not shown) at the same rotational peripheral speed as that of the driven rotation. When a one-way clutch (not shown) is interposed between the support shaft 5a and the drive gear 22 and the drive means (not shown) is continuously operated during the rotation of the plate cylinder 3, and the press roller 5 occupies the pressure contact position. A configuration may be adopted in which the rotational force of the press roller 5 is not transmitted to a driving means (not shown).

  A brush roller 24 that cleans the press roller 5 is disposed between the arm members 18 and 19 and above the press roller 5. As shown in FIG. 4, the brush roller 24 has a paper-made cylindrical core member 25, metal rotating shafts 26 and 27 press-fitted to both end portions of the core member 25, and a brush-like surface property. The axial length of the sheet material 28 is the same as the axial length of the press roller 5. The diameter of the core member 25 is about 18 to 24 mm in this embodiment, and the rotary shaft 26 includes a press-fit portion 26a having a tapered surface at the tip, a flange portion 26b that contacts the side end of the core member 25, and a shaft portion 26c. Have. Similarly, the rotary shaft 27 has a press-fit portion (not shown), a flange portion 27b, and a shaft portion 27c, and the tips of the shaft portions 26c and 27c are each formed in a tapered shape.

As shown in FIG. 5, the sheet material 28 is made of, for example, a synthetic resin fiber such as PPS (polyphenylene sulfide), nylon, acrylic fiber, polyester fiber, or a natural fiber such as cotton or wool having a thickness of 0.6 to 1.. A plurality of brushes 28b made of a fibrous member are implanted on a base material 28a of about 0 mm. The thickness of the brush 28b is 70 to 100 denier (d) / 5 filament (f), and it is planted by V weaving or W weaving at a density of 2500 to 3000 filaments / inch ² with 5 filament yarns. In this embodiment, the sheet material 28 is formed to have a width of 30 mm and a thickness of 2 to 5 mm, and is wound around and adhered to the peripheral surface of the core material 25 in a spiral manner. Thereby, the brush roller 24 which has the some brush 28b in the surrounding surface is formed.

  As shown in FIG. 3, an opening 18a is formed in the arm member 18, and a bearing member 29 that rotatably supports the rotary shaft 27 is attached to the opening 18a so as to be movable up and down. The bearing member 29 includes a bearing portion 29a that rotatably supports the shaft portion 27c, and a guide portion 29b that guides the shaft portion 27c to the bearing portion 29a, and is oil-impregnated so that the shaft portion 27c can rotate in contact. It is formed of a system sintered member. The bearing member 29 is urged downward in FIG. 3 by a compression spring 30 provided in the opening 18a.

  The arm member 19 is formed with an opening 19a and a tap 19b having a size that allows the brush roller 24 to pass therethrough, and a guide pin 31 is implanted therein. A positioning hole 32a formed in the mounting member 32 is fitted into the guide pin 31, and the mounting member 32 is fixed to the arm member 19 by screwing a screw 33 into the tap 19b. An opening 32b is formed in the attachment member 32, and a bearing member 34 that rotatably supports the rotary shaft 26 is attached to the opening 32b so as to be movable up and down. The bearing member 34 has a bearing portion 34a that rotatably supports the shaft portion 26c, and is formed of an oil-impregnated sintered member so that the shaft portion 26c can rotate in contact with the shaft member 26c. The bearing member 34 is urged downward in FIG. 3 by a compression spring 35 provided in the opening 32b.

  3, the brush roller 24 is inserted into the opening 19a in the direction of arrow A from the left side of the arm member 19 in FIG. 3, the shaft portion 27c is fitted into the bearing portion 29a, and the brush roller 24 is attached to each arm member 18, 19 between. From this state, the attachment member 32 is attached to the arm member 19 from the left side in FIG. 3 by screwing the screw 33 with the tap 19b in a state where the positioning hole 32a is fitted to the guide pin 31. 26c is fitted to the bearing portion 34a. Thereby, the brush roller 24 is rotatably supported between the arm members 18 and 19. At this time, each opening 18a, 32b is formed in such a size that the bearing member 29, 34 does not contact each opening 18a, 32b even though the peripheral surface of the brush roller 24 contacts the peripheral surface of the press roller 5. Thus, the brush roller 24 is configured to come into contact with the peripheral surface of the press roller 5 by the urging force of the compression springs 30 and 35. The respective compression springs 30 and 35 are set to have respective materials, spring constants, and shapes so that the brush roller 24 is uniformly pressed against the peripheral surface of the press roller 5 with a predetermined pressing force. The brush roller 24 is disposed so that the tip of each brush 28b is in contact with the peripheral surface of the press roller 5 by about 0.2 to 0.5 mm, and is rotated while the press roller 5 rotates.

  A paper feed tray 6 is disposed on the right side of the plate cylinder 2. A paper feed tray 6 on which a plurality of sheets P are stacked on the upper surface is supported by an apparatus main body (not shown) so as to be movable up and down, and is moved up and down by an elevator means (not shown). The paper feed roller 7 that is rotationally driven by a drive means (not shown) is rotatably supported by a bracket (not shown) that is swingably supported by an apparatus main body side plate (not shown), and the paper feed tray 6 occupies the upper limit position. At this time, the uppermost sheet P on the sheet feeding tray 6 is pressed with a predetermined pressing force. The paper feed roller 7 separates and feeds the paper P on the paper feed tray 6 in cooperation with a separation member (not shown).

  A registration roller pair 8 is disposed on the left side of the paper feed roller 7. The registration roller pair 8 including a driving roller and a driven roller pressed against the driving roller is supplied with a driving force from a plate cylinder driving means (not shown), and the driving roller rotates in synchronization with the plate cylinder 2, thereby The paper P separated and fed by the paper roller 7 is fed between the plate cylinder 2 and the press roller 4 at a predetermined timing.

  A sheet conveying means 9 is disposed between the plate cylinders 2 and 3. The sheet conveying means 9 includes a driving roller 9a and a driven roller 9b composed of a plurality of finely divided rollers, an endless belt 9c, a suction fan 9d, and the like. Each drive roller 9a is fixed to the same support shaft, and each driven roller 9b is arranged corresponding to each drive roller 9a. Endless belts 9c each having a plurality of holes are spanned between each driving roller 9a and each driven roller 9b, and each endless belt 9c is driven by rotation of each driving roller 9a by driving means (not shown). It is moved in the direction indicated by the arrow in FIG. The suction fan 9d is operated by a fan driving means (not shown), and sucks air when each endless belt 9c is moved to suck the paper P onto each endless belt 9c. The operation of the driving means (not shown) is controlled by a control means (not shown), and the paper transport means 9 applies the single-side printed paper P printed on one surface thereof by the plate cylinder 2 and the press roller 4 at a predetermined timing. 3 is fed toward the press roller 5.

  The paper discharge tray 10 is disposed at the end of the paper transport path 36 in order to stack a large number of sheets P printed on both sides. The paper discharge tray 10 is provided with one end fence 37 with which the leading end of the paper P abuts and a pair of side fences (not shown) that align the paper P in the width direction.

  Based on the above configuration, the operation of the duplex printing apparatus 1 will be described below. When an operator sets a document to be printed on an image reading device (not shown) and presses a plate making start key (not shown), a plate discharging device (not shown) corresponding to the plate cylinder 2 and a plate discharging device (not shown) corresponding to the plate cylinder 3 are operated. Then, the used masters 12 and 13 are peeled off from the outer peripheral surfaces of the plate cylinders 2 and 3, respectively. Thereafter, when the clampers 11 and 13 are opened after the plate cylinders 2 and 3 occupy a predetermined plate feeding position, a plate making apparatus (not shown) corresponding to the plate cylinder 2 and a plate making apparatus (not shown) corresponding to the plate cylinder 3 are used. The masters 12 and 14 on which the plate-making images corresponding to the document images are formed are wound on the outer peripheral surfaces of the plate cylinders 2 and 3, respectively. The plate making operation may be performed based on image information transmitted from an external connection device (not shown) such as a personal computer.

  After the masters 12 and 14 having been subjected to the plate making are wound on the plate cylinders 2 and 3, when the operator presses a print start key (not shown), the directions of the plate cylinders 2 and 3 are indicated by arrows in FIG. And the paper feed roller 7 is rotated and the paper P is sequentially separated and fed from the paper feed tray 6. As the plate cylinder 3 rotates, the press roller 5 occupying the separated position is also driven to rotate clockwise in FIG. The separately fed paper P is temporarily stopped by the registration roller pair 8, and then the registration roller pair 8 rotates at a predetermined timing when the leading edge of the plate-making image formed on the master 12 coincides with the image forming position of the paper P. Thus, the sheet is fed toward the space between the plate cylinder 2 and the press roller 4 with the skew corrected.

  After the registration roller pair 8 is actuated, the unillustrated swinging means is actuated to cause the press roller 4 to occupy the pressure contact position, and the upper surface, which is one side of the fed paper P, is given to the master 12 on the plate cylinder 2. It is pressed by the pressure of By this pressure contact, the ink supplied from the ink supply means (not shown) to the inner peripheral surface of the plate cylinder 2 is transferred to the upper surface of the paper P through the opening portion of the plate cylinder 2 and the perforation portion of the master 12.

  The paper P with the printed image transferred on the upper surface is sent to the paper conveying means 9 and the driving means (not shown) is activated at a predetermined timing when the leading edge of the plate-making image formed on the master 14 coincides with the image forming position of the paper P. As a result, the sheet is conveyed by suction to the downstream side of the sheet conveying path 36 by the sheet conveying means 9.

  After the operation of the driving means (not shown), the swinging means (not shown) is actuated, so that the press roller 5 occupies the press contact position, and the lower surface, which is the other surface of the fed paper P, is predetermined on the master 14 on the plate cylinder 3. It is pressed by the pressure of By this pressure contact, the ink supplied from the ink supply means (not shown) to the inner peripheral surface of the plate cylinder 3 is transferred to the lower surface of the paper P through the opening portion of the plate cylinder 3 and the punch portion of the master 14. The paper P on which the printed images are transferred on both sides and both sides are printed is discharged and stacked on the paper discharge tray 10.

  In the above-described double-sided printing operation, the press roller 5 used as the backside printing press roller contacts the surface of the paper P after the surface printing of the paper P in a state where the transferred ink is not completely dry. Further, a peripheral surface having fine irregularities is employed so that the ink from the paper P is difficult to be retransferred on the peripheral surface. However, as described in the “Background Art” column, since this configuration alone cannot prevent retransfer of ink from the paper P, a cleaning member that contacts the press roller 5 to clean the peripheral surface is disposed. is doing.

  In addition, as described in the column “Problems to be Solved by the Invention”, when the cleaning member is rotationally driven to generate a speed difference with the press roller 5, the speed difference with the cleaning member becomes a load. The rotational peripheral speed of the press roller 5 becomes slower than the rotational peripheral speed of the plate cylinder 3, and the rotational peripheral speed between the plate cylinder 3 and the press roller 5 when the press roller 5 contacts the master 14 on the plate cylinder 3. Due to the difference, a load is applied to the master 14 and problems such as plate elongation and image distortion occur, so that the cleaning member is driven to rotate by the press roller 5.

  In the present embodiment, the press roller 5 is rotationally driven. However, even when the press roller 5 is rotationally driven, the driving force transmission mechanism of the press roller 5 in a state where the press roller 5 occupies the separated position, In this embodiment, a change in tension occurs in the timing belt, and a slight peripheral speed difference occurs between the plate cylinder 3 and a load is applied to the master 14. Even in the case of gear driving, a slight peripheral speed difference is generated between the press cylinder 5 and the plate cylinder 3 in a state where the press roller 5 occupies the separated position, and a load is applied to the master 14. However, since the difference between the peripheral speeds is much smaller than when the press roller 5 is not driven to rotate, the resulting plate elongation and image distortion are minute. When the press roller 5 is not driven to rotate, the press roller 5 rotates by inertia in a state where the press roller 5 is occupied, and when the press contact position is occupied next, a certain peripheral speed difference between the press roller 5 and the plate cylinder 3 is obtained. Since the inertial rotation of the press roller 5 is hindered by the contact of the cleaning member and the peripheral speed difference is further increased, the load on the master 14 is increased as compared with the case where the press roller 5 is driven to rotate. Will be.

  Here, the background of selecting the brush roller 24 as a cleaning member for cleaning the peripheral surface of the press roller 5 having fine irregularities will be described. As a cleaning member, a sheet material having a felt-like or loop-like surface property in addition to the brush roller 24 can be cleaned when there is a difference in peripheral speed from the press roller 5. This is disclosed in Japanese Unexamined Patent Publication No. 2004-338234. Therefore, when a cleaning roller having a brush-like surface property is used as a cleaning member, a cleaning roller having a felt-like surface property is used, or a cleaning roller having a loop-like surface property is used. The cleaning performance when the roller was driven to rotate by the press roller 5 and when each cleaning roller was rotationally driven was confirmed by experiments. The experimental results are shown in Table 1.

  As is apparent from the results in Table 1, the cleaning performance and durability are best when a cleaning roller having a brush-like surface property is used, and the brush roller 24 is employed in the present invention based on this result. This is because the surface has a brush shape, so that the tip of the brush 28b enters a gap between minute irregularities formed on the peripheral surface of the press roller 5, and the ink and paper powder are satisfactorily removed by the brush 28b. This is probably because of this. Further, when the cleaning roller is driven to rotate with respect to the press roller 5 as in the present invention, dirt on the surface of the roller other than the cleaning roller having a brush-like surface property immediately becomes saturated. It was found that ink stains remained on the peripheral surface and image stains occurred.

  From the above, according to the present invention, by using the brush roller 24 that rotates in contact with the peripheral surface of the press roller 5 for backside printing that has a plurality of fine irregularities on its peripheral surface, It is possible to effectively prevent ink stains from remaining on the peripheral surface, and to prevent image stains from occurring, and since no load is applied to the master 14 when the press roller 5 is in contact, plate elongation and image distortion can be prevented. And a good image can be obtained.

  According to the above-described configuration, the attachment member 32 can be easily attached to and detached from the arm member 19 with the screw 33, and the attachment and detachment of the brush roller 24 to the apparatus main body can be easily performed. The space required for facilitation and replacement can be reduced. The brush roller 24 includes a paper core 25, metal rotary shafts 26 and 27 press-fitted on both sides of the core 25, and a sheet material 28 having a brush-like surface property. Therefore, it can be easily incinerated by removing the metal rotating shafts 26 and 27, and the separation process in recycling becomes easy. Further, since the brush roller 24 is a consumable item that is replaced when the dirt becomes severe and the cleaning function is deteriorated, the brush roller 24 is required to be inexpensive, lightweight, and easy to handle. This is also desirable. Furthermore, since the sheet material 28 is spirally wound and bonded to the core material 25, it is difficult to peel off and a uniform cleaning function can be obtained over the entire circumference and the entire axial direction.

  In the above configuration, the brush roller 24 is pressed against the peripheral surface of the press roller 5 with a predetermined pressing force by the urging force of the compression springs 30 and 35. Here, the pressure contact force of the brush roller 24 to the peripheral surface of the press roller 5 will be described. As a result of experiments by the present inventor, since there are a plurality of fine irregularities on the peripheral surface of the press roller 5, if the pressure contact force of the brush roller 24 is too strong, the brush roller 24 peels off or breaks during long-time use. However, it has been found that if the brush 28b is too weak, the tip of the brush 28b does not uniformly contact the peripheral surface of the press roller 5 and the cleaning effect is lost. Further, when the pressure contact force of the brush roller 24 is increased, the resistance force against the rotation of the press roller 5 is increased, and when the press roller 5 is pressed against the plate cylinder 3, a difference in peripheral speed occurs between the two, and the load on the master 14 is increased. It was found that plate elongation and image distortion occurred. Further, as shown in the present embodiment, when the brush roller 24 is slid in the axial direction and mounted between the arm members 18 and 19, if the urging force of the compression springs 30 and 35 is too strong, the mounting operation is performed. It turned out to be difficult to do. Therefore, the pressure contact force of the brush roller 24 was changed, and the occurrence of image distortion, the surface durability of the brush roller 24, and the mounting workability were investigated. The survey results are shown in Table 2.

  As is apparent from the results in Table 2, it has been found that when the pressure contact force of the brush roller 24 is 600 gf or more, problems such as image distortion, damage to the brush roller 24, and deterioration in mounting workability occur. Further, it was found that when the pressure contact force of the brush roller 24 is less than 200 gf, a satisfactory cleaning effect cannot be obtained. From this, the pressure contact force of the brush roller 24 with respect to the peripheral surface of the press roller 5 is set to 400 gf or less, preferably 200 to 400 gf.

  FIG. 6 shows a second embodiment of the present invention. Compared with the first embodiment, the second embodiment is different only in that it has a removal member 38 as a contact member, and the other configurations are the same.

  The removal member 38 is secured to the bracket 39 fixed to the arm members 18 and 19 by virtue of an appropriate means such as adhesive or tape, and the free end thereof is attached to the tip of the brush 28b. In contact. The removing member 38 made of a polyethylene terephthalate thin resin plate having a thickness of about 0.05 to 0.2 mm is formed so that its width is slightly larger than the width of the brush roller 24, and the brush roller 24 is pressed. The tip of the brush 28b is in contact with the roller 5 from a direction orthogonal to the direction in which the roller 5 is pressed. The disposing position of the removing member 38 is set so that the free end thereof overlaps the outer peripheral surface of the brush roller 24 by about 0.5 to 1.0 mm (enters inward in the radial direction of the brush roller 24).

  According to the second embodiment, after the removing member 38 and the brush 28b come into contact with each other, the ink or paper powder attached to the tip of the brush 28b is blown off by the elastic deformation of the brush 28b. It becomes possible to improve the property. The removing member 38 is an elastic body, and the removing member 38 is elastically deformed when in contact with the brush 28b, so that no load is applied to the rotation of the brush roller 24. The rotation of the driven roller is not obstructed, and when the press roller 5 is pressed against the plate cylinder 3 due to the load of the brush roller 24, a difference in peripheral speed occurs between them, and the master 14 is loaded and plate elongation and image distortion occur. Can be prevented. Further, since the removing member 38 contacts the tip of the brush 28b from a direction orthogonal to the direction in which the brush roller 24 is pressed against the press roller 5, the brush roller 24 is not subjected to an excessive load, and the brush When the press roller 5 presses against the plate cylinder 3 due to the load of the roller 24, a peripheral speed difference is generated between the two, and it is possible to prevent the master 14 from being loaded and causing plate elongation and image distortion.

  FIG. 7 shows a third embodiment of the present invention. The third embodiment is different from the second embodiment only in that it has a removal member 40 as a contact member and a bracket (not shown) instead of the removal member 38 and the bracket 39, and other configurations. Are the same.

  The removal member 40 made of a metal or resin flat knurl having a star-shaped cross section is rotatable at both ends of the support shaft 40a by brackets (not shown) fixed to the arm members 18 and 19 in the vicinity of both ends. The peripheral surface is in contact with the tip of the brush 28b. The removal member 40 having a groove pitch of about 0.5 to 1.0 and a diameter of about 6 to 10 mm in the present embodiment has a width slightly larger than the width of the brush roller 24. The brush roller 24 is in contact with the tip of the brush 28b from a direction orthogonal to the direction in which the brush roller 24 is pressed against the press roller 5. The disposition position of the removing member 40 is set so that the peripheral surface overlaps the outer peripheral surface of the brush roller 24 by about 0.5 to 1.0 mm.

  According to the third embodiment, after the removing member 40 and the brush 28b come into contact with each other, the ink or paper dust attached to the tip of the brush 28b is blown off by the elastic deformation of the brush 28b. It becomes possible to improve the property. Further, the removing member 40 is a rotating body, and the removing member 38 is driven to rotate at the time of contact with the brush 28b so that no load is applied to the rotation of the brush roller 24. The rotation of the driven roller is not obstructed, and when the press roller 5 is pressed against the plate cylinder 3 due to the load of the brush roller 24, a difference in peripheral speed occurs between them, and the master 14 is loaded and plate elongation and image distortion occur. Can be prevented. Furthermore, since the removing member 40 contacts the tip of the brush 28b from a direction orthogonal to the direction in which the brush roller 24 is pressed against the press roller 5, the brush roller 24 is not subjected to an excessive load, and the brush When the press roller 5 presses against the plate cylinder 3 due to the load of the roller 24, a peripheral speed difference is generated between the two, and it is possible to prevent the master 14 from being loaded and causing plate elongation and image distortion. Furthermore, since the removal member 40 is a solid made of metal or resin, the durability of the removal member 40 can be significantly improved as compared with the second embodiment.

  In each of the first to third embodiments described above, the stencil printing apparatus to which the brush roller 24 and the removal members 38 and 40 can be applied is arranged in correspondence with two plate cylinders 2 and 3. Two press rollers 4 and 5 are provided, and after the surface image is printed on one surface (upper surface) of the paper P by the plate cylinder 2 and the press roller 4, the paper P on which the surface has been printed is transported to the paper 9 shows the double-sided printing apparatus 1 that conveys downstream by the plate cylinder 3 and the press roller 5 and prints the back side image on the other side (lower side) of the paper P. However, the brush roller 24 and each removing member 38, For example, as shown in FIG. 8, 40 may be applied to a double-sided printing apparatus 41 similar to that disclosed in Japanese Patent Laid-Open No. 2003-200355. Hereinafter, this application example will be described as a fourth embodiment.

  In FIG. 8, the duplex printing apparatus 41 includes a printing unit 42, a plate making unit 43, a sheet feeding unit 44, a plate discharging unit 45, a sheet discharging unit 46, an image reading unit 47, an auxiliary tray 48, a refeed unit 49, a switching claw 50, A brush roller 51 and the like are included.

  The printing unit 42 disposed substantially at the center of the apparatus main body includes a plate cylinder 52 and a press roller 53. The plate cylinder 52 is rotatably supported by the apparatus main body and is driven to rotate by a plate cylinder driving means (not shown). The plate cylinder 52 has an openable / closable clamper 54 on its outer peripheral surface, and a divided pre-made master 55 made by the plate making unit 43 is wound on the outer peripheral surface of the plate cylinder 52. In the divided plate-making master 55, a plate-making image corresponding to the front surface image and a plate-making image corresponding to the back image are formed in the circumferential direction, and an unmade portion is formed between the plate-making images. On the plate cylinder 52, the divided plate-making master 55 has a plate-making image corresponding to the front image in the front surface area shown in FIG. 8, a plate-making image corresponding to the back image in the same back surface area, and a non-plate making portion in the intermediate area. Each is wound to correspond.

  A press roller 53 is disposed below the plate cylinder 52. A press roller 53 formed in the same manner as the press roller 5 and having a plurality of fine irregularities on its peripheral surface is rotatably supported by a pair of arm members (not shown). By swinging by the moving means, the separation surface shown in FIG. 8 where the circumferential surface is separated from the plate cylinder 52 and the circumferential surface are pressed against the divided plate-making master 55 on the plate cylinder 52 with a predetermined pressure contact force. It selectively occupies the pressure contact position. A press roller driving means (not shown) is connected to the press roller 53. When the press roller 53 occupies the separated position, the press roller 53 is rotationally driven by the press roller driving means at the same linear velocity as that of the plate cylinder 52.

  A brush roller 51 is disposed in the vicinity of the peripheral surface of the press roller 53. The brush roller 51 is configured in the same manner as the brush roller 24, and is rotatably supported between arm members (not shown) that support the press roller 53. The brush roller 51 is disposed so that the tip of the brush is in contact with the circumferential surface of the press roller 53 by about 0.2 to 0.5 mm, and is rotated in a driven manner when the press roller 53 rotates.

  In the vicinity of the right side of the press roller 53, a refeed guide member 56 for transporting the surface-printed paper P sent from the refeed means 49 along the peripheral surface of the press roller 53 is disposed. A re-feeding registration roller 57 is provided below the press roller 53 to send out the surface-printed paper P stored on the auxiliary tray 48 in contact with the peripheral surface of the press roller 53. A refeed conveyance means 58 having an auxiliary tray 48 on the upper surface is disposed on the lower left side of the press roller 53, and a refeed positioning member 59 is provided integrally therewith. A paper receiving plate 60 that is movable along the upper surface of the auxiliary tray 48 is disposed above the re-feed conveying means 58. The auxiliary tray 48, the refeed guide member 56, the refeed registration roller 57, the refeed conveyance unit 58, the refeed positioning member 59, and the sheet receiving plate 60 constitute a refeed unit 49.

  On the left side of the contact position between the plate cylinder 52 and the press roller 53 and on the transport path of the paper P, a switching claw 50 is disposed. The switching claw 50 is rotatably supported by the apparatus main body at the downstream end portion in the sheet conveying direction, and is moved by a moving means (not shown), and the first position shown by a practical example in FIG. 2 positions are selectively occupied. The paper P that has passed between the plate cylinder 52 and the press roller 53 is guided to the paper discharge unit 46 when the switching claw 50 occupies the first position, and the switching claw 50 occupies the second position. Is guided to the auxiliary tray 48.

  A plate making unit 43 is disposed on the upper right side of the printing unit 42. The plate making unit 43 has a well-known configuration including a master storage member, a platen roller, a thermal head, a master cutting unit, a master stock unit, a tension roller pair, a reversing roller pair, and the like. The

  A sheet feeding unit 44 is disposed below the plate making unit 43. The paper feed unit 44 has a known configuration including a paper feed tray 61, a paper feed roller 62, a separation roller 63, a separation pad 64, a registration roller pair 65, and the like.

  The plate discharging unit 45 disposed on the upper left side of the printing unit 42 also has a well-known configuration having an upper plate discharging member, a lower plate discharging member, a plate discharging box, a compression plate, and the like. Peel off from the peripheral surface of the and dispose of in the waste box.

  A paper discharge unit 46 is disposed below the plate discharge unit 45. The paper discharge unit 46 includes a peeling claw, a paper discharge conveyance unit 66, a paper discharge tray 67, and the like. The paper discharge transport unit 66 is configured in the same manner as the paper transport unit 9 and transports the printed paper P to the downstream side while sucking the printed paper P on the upper surface of the endless belt. The paper discharge tray 67 has one end fence 68 and a pair of side fences 69, and the printed paper P is stacked on the upper surface thereof.

  An image reading unit 47 is disposed in the upper part of the apparatus main body. The image reading unit 47 is a contact glass on which a document is placed, a pressure plate that can be moved toward and away from the contact glass, a scanning unit that scans and reads a document image, a lens that focuses the scanned image, and processes the focused image. An image sensor or the like.

Based on the above configuration, the operation of the duplex printing apparatus 41 will be described below.
When a document to be printed is set in the image reading unit 47 and a plate making start key (not shown) is pressed by the operator, a document image reading operation is performed in the image reading unit 47 and the plate discharging unit 45 is operated to operate the plate cylinder 52. The used divided plate-making master 55 is peeled from the outer peripheral surface of the plate. After the plate removal, the plate making unit 43 is operated to make a new divided plate-made master 55, which is wound around the plate cylinder 52.

  After the winding operation is completed and the duplex printing apparatus 41 enters a print standby state, when an operator presses a print start key (not shown) after setting various printing conditions, the plate cylinder 52 is driven to rotate at a set speed. Then, the sheet feeding roller 62 and the separation roller 63 are operated to feed one sheet P located on the uppermost position on the sheet feeding tray 61. The fed paper P is temporarily stopped by the registration roller pair 65 and then sent between the plate cylinder 52 and the press roller 53 at a predetermined timing.

  When the plate cylinder 52 rotates to a predetermined angle and the surface area occupies a predetermined position corresponding to the press roller 53, the press roller 53 occupies the press contact position, so that the paper P is transferred to the divided plate-making master 55 on the plate cylinder 52. The surface image is transferred to one surface of the pressure contact. The surface-printed paper P is peeled off from the outer peripheral surface of the plate cylinder 52 and then sent to the refeed conveyance means 58 by the switching claw 50 occupying the second position. At this time, the front end of the paper P is received by the paper receiving plate 60 and is placed on the auxiliary tray 48 from the rear end side. The paper P on the auxiliary tray 48 is transported in the direction of the arrow in FIG. 8 by the refeed transporting means 58, and is temporarily stopped with its leading end abutting on the refeed positioning member 59.

  The plate cylinder 52 continues to rotate while the first sheet P is being guided on the auxiliary tray 48, and the second sheet is fed from the sheet feeding unit 44 at the same timing as the first sheet P. P is fed. Similarly to the first sheet P, the fed second sheet P has a surface image transferred to one surface thereof by the press roller 53 and is then switched by the switching claw 50 occupying the second position. It is sent to the re-feed conveyance means 58.

  After the second sheet P is fed from the sheet feeding unit 44, the sheet re-feeding registration roller 57 operates at a timing slightly earlier than the back surface area of the plate cylinder 52 reaches the position corresponding to the press roller 53. Then, the first sheet P stored on the auxiliary tray 48 is pressed against the peripheral surface of the press roller 53. The first sheet P that is pressed against the peripheral surface of the press roller 53 is conveyed toward the abutting portion with the plate cylinder 52 by the rotational force of the press roller 53 that is in contact with the plate cylinder 52 and is driven to rotate. The back image is transferred to the other surface by being pressed against the divided master-making master 55. At this time, the press roller 53 functions as a press roller for back side printing.

  The first sheet P, which has been transferred to the back side and has been printed on both sides, is guided to the sheet discharge conveying means 66 by the switching claw 50 occupying the first position, and is discharged onto the sheet discharge tray 67. The Thereafter, the above operation is repeated until the set number of printed sheets is consumed. When the set number of printed sheets is reached, the operation of each part is stopped and the printing operation is completed.

  During the printing operation described above, the press roller 53 contacts the image surface of the paper P when the surface-printed paper P is pressed from the auxiliary tray 48 by the re-feeding registration roller 57. At this time, the paper P Since the ink transferred to the surface is in an undried state, the ink is retransferred and the peripheral surface thereof becomes dirty. However, the brush roller 51 configured in the same manner as the brush roller 24 is in contact with the peripheral surface of the press roller 53 and is driven to rotate, so that the press roller 53 does not apply a load to the divided master plate 55 on the plate cylinder 52. The peripheral surface can be cleaned, and the same effects as those of the first embodiment can be obtained.

  Also in the fourth embodiment, the pressure contact force of the brush roller 51 with respect to the press roller 53 is 400 gf as in the first embodiment in consideration of the occurrence of image distortion, the surface durability of the brush roller 51, and the mounting workability. Hereinafter, it is desirably set to 200 to 400 gf.

  Also in the fourth embodiment, the same removal members 38 and 40 as those shown in the second and third embodiments can be provided, thereby the same effect as the second and third embodiments. Can be obtained.

1 is a schematic front view of a double-sided printing apparatus that employs a first embodiment of the present invention. It is a partial schematic sectional drawing of the press roller used for each 1st thru | or 3rd embodiment of this invention. It is the schematic explaining the support mechanism of the press roller and brush roller used for each 1st thru | or 3rd embodiment of this invention. It is a partial cross-sectional schematic diagram of the brush roller used for each 1st thru | or 3rd embodiment of this invention. It is the schematic explaining the surface property of the brush roller used for each 1st thru | or 3rd embodiment of this invention. It is the schematic explaining the removal member used for the 2nd Embodiment of this invention. It is the schematic explaining the removal member used for the 3rd Embodiment of this invention. It is a schematic front view of the double-sided printing apparatus which employ | adopted the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,41 Duplex printing apparatus 2 1st printing cylinder 3 2nd printing cylinder 4 1st press roller 5 2nd press roller (press roller for back surface printing)
12, 14 Master 24, 51 Brush roller 28a Base material 28b Brush 38, 40 Contact member (removal member)
53 Press roller (press roller for backside printing)
55 Divided master P paper

Claims (7)

A plate cylinder on which the master is wound, and a press roller disposed in contact with and separated from the plate cylinder that presses the paper against the master, and prints a surface image on one surface of the paper. In a double-sided printing apparatus that performs a backside printing step of printing a backside image on the other side of the paper after performing a frontside printing step,
Backside printing press roller used in the back printing process as well as have a plurality of fine irregularities on its periphery, have a brush roller is driven to rotate in contact with the peripheral surface of the rear surface printing press roller, wherein The press roller for printing on the back surface is driven to rotate with the plate cylinder when the paper is pressed against the master, and is driven to rotate at the same peripheral speed as the driven rotation when being separated from the master, and comes into contact with the brush roller. A contact member that contacts the brush roller from a direction perpendicular to the contact direction of the brush roller with respect to the press roller for printing on the back surface, and is elastically deformable when contacting the brush roller. There is a double-sided printing apparatus. The double-sided printing apparatus according to claim 1,
The double-sided printing apparatus, wherein the brush roller is formed by implanting a brush made of a fibrous member on a base material . The double-sided printing apparatus according to claim 2 ,
The brush is 70 to 100 denier / 5 filaments, double-sided printing apparatus in which the planted bristle density is characterized in that it is a 2500 to 3000 present / inch ^2. In the double-sided printing apparatus according to any one of claims 1 to 3 ,
The double-sided printing apparatus, wherein a contact pressure of the brush roller with respect to the back surface printing press roller is 400 gf or less . In the double-sided printing apparatus according to any one of claims 1 to 4,
The double-sided printing apparatus, wherein the brush roller is detachable from the apparatus main body . The double-sided printing apparatus according to any one of claims 1 to 5,
A first plate cylinder disposed as one side of the paper as the plate cylinder and a downstream side in the paper transport direction from the first plate cylinder and opposed to the other side of the paper. A first printing roller having a second printing cylinder, and a second pressing roller capable of making contact with and separating from the first printing cylinder; Then, after performing the front surface printing step with the first plate cylinder and the first press roller, the front surface printed paper is conveyed and the back surface printing step is performed with the second plate cylinder and the second press roller. A double-sided printing apparatus, wherein the second press roller functions as the back-side printing press roller . The double-sided printing apparatus according to any one of claims 1 to 5 ,
As the master, a divided plate-making master having a first plate-making image and a second plate-making image in its length direction is wound around the plate cylinder, and the paper is pressed against the plate cylinder by the press roller. After the surface image is printed on one side of the sheet and the surface printing step is performed, the surface-printed paper is re-fed and pressed against the plate cylinder by the press roller. A double-sided printing apparatus that performs the backside printing step of printing the backside image on an unprinted side, wherein the press roller functions as the backside printing press roller .

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