JP3790293B2 - Printing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, a printing paper is fed by aligning the position with a pre-printed master wound around a rotatable printing cylinder, the printing paper is pressed against the printing cylinder via the master, and the ink in the printing cylinder is transferred to the printing cylinder. The present invention relates to a printing apparatus that prints an image on a printing paper by causing ink to ooze out from a hole and a master hole and transfer ink to the printing paper.
[0002]
[Prior art]
A plate cylinder used in this type of printing apparatus is formed by winding a plurality of layers of resin or metal mesh screens on the outer periphery of a cylindrical body having a large number of holes formed on the outer periphery. The master has a laminate structure in which a thermoplastic resin film having a thickness of about 1 to 2 μm is laminated with a porous Japanese paper, a synthetic fiber sheet, or a sheet obtained by mixing a Japanese paper and a synthetic fiber sheet. In this master, the film surface is in contact with a thermal head having a large number of heating elements arranged in the main scanning direction, and ink is spread by selectively heating the heating elements in the process of transporting the master in the sub-scanning direction. Through holes (dots) are formed.
[0003]
In such a master, when Japanese paper or a synthetic fiber sheet or the like is intertwined in a complicated manner, or a thick fiber crosses the perforated portion, ink cannot pass through the portion. As a result, when black solid printing is performed, an image is lost, fine lines or characters are faint, and a phenomenon commonly referred to as a fiber pattern occurs, resulting in poor image quality. Therefore, attempts have been made to form a master using only a thermoplastic resin film without using Japanese paper or a synthetic fiber sheet, or to reduce the fiber mesh by reducing the thickness of the Japanese paper or synthetic fiber sheet.
[0004]
Since such a master is weak, wrinkles are likely to occur due to shrinkage of the thermoplastic resin film, and waves are struck when the master is wound around a plate cylinder. When the master is wound around the plate cylinder in such a state, when the printing paper is pressed against the master on the plate cylinder by a pressing member such as a press roller, the wrinkled portion and the wavy portion of the master are caused by the adhesive force of the ink to cause the plate cylinder. The image cannot be moved and is crushed and the image quality is deteriorated.
[0005]
By the way, in the case of a master in which Japanese paper or synthetic fiber sheet is stacked on a thermoplastic resin film, even if it is pressed against the surface of the plate cylinder by the pressing member, the plate cylinder resists the adhesive force of the ink because it is stiff. As the surface of the surface is slid, wrinkles are unlikely to occur, and even if they occur, the degree is small.
[0006]
For this reason, even when using a master made only of a thermoplastic resin film that does not overlap Japanese paper or synthetic fiber sheet, when wrinkling the master around the plate cylinder, stretch the wrinkled or wavy part of the master. Proposals have been made.
[0007]
For example, Japanese Utility Model Publication No. 60-21243 describes that both sides of the master are pressed by inclined rollers and pulled outward, and the master is extended by an elastic member that presses the central portion of the master.
[0008]
Japanese Utility Model Publication No. 62-20297 discloses an elastic member in which the edge portion of the master that is pulled by the plate cylinder is inclined toward the entrance direction of the master from the central portion toward both end portions. It is described that wrinkles or the like generated in the master are extended outwardly by being pressed against each other.
[0009]
Furthermore, Japanese Patent Application Laid-Open No. 7-125399 describes that the master is pressed against the surface of the plate cylinder by a spreading roller over its entire width.
[0010]
[Problems to be solved by the invention]
However, even those described in these publications are difficult to reliably stretch a weak master. In particular, in the proposal described in the aforementioned Japanese Utility Model Publication No. 60-21243, as shown in FIG. 10, the elastic member B is arranged on the downstream side in the conveyance direction (arrow direction) of the master A, and the upstream side is inclined. Since the roller C is disposed, the master A may be pressed by the elastic member B even if it passes through the inclined roller C. At this time, both sides of the master A are released from the inclined roller C, and only the central part is stretched by the elastic member B. Therefore, vertical wrinkles approach the central part, or only the central part is stretched, so that wrinkles occur diagonally. To do. Such a phenomenon occurs more remarkably when the image area is large, in other words, the higher the density of dots perforated by the thermal head, the weaker the master becomes.
[0011]
[Means for Solving the Problems]
  The printing apparatus according to claim 1, wherein a preprinted master is wound around a plate cylinder, the printing paper is fed to an outer periphery of the plate cylinder in alignment with the master, and the printing paper is passed through the master to the plate. In a printing apparatus which presses against a cylinder and prints an image on the printing paper by transferring ink from the master made on the printing cylinder to the printing paper, the transfer path of the master toward the printing cylinder A pair of transport rollers arranged immediately before the plate cylinder along the master cylinder, arranged downstream of the transport rollers along the master transport path and at a position where both sides in the width direction of the master are pressed. By rotating with a rotation center inclined with respect to the width direction of the master by the frictional force with the master pulled by the rotating plate cylinder, the master is moved outward in the width direction. A pair of inclined rollers that are pulled, and are located on the downstream side of the conveying roller along the conveying path of the master and from the vicinity on the line connecting the contact points of the inclined rollers to the master approaching the plate cylinder side An elastic member disposed at a position that is not in contact with the central portion in the width direction of the master, and further contacts and separates the inclined roller and the elastic member with respect to the master selectively. Drive mechanismAnd the operation of the contact / separation drive mechanism so that the inclined roller and the elastic member are separated from the master immediately before the rear end of the master whose tip is supported by the plate cylinder passes through the inclined roller and the elastic member. Separation time control means,It has. Therefore, if the inclined roller and the elastic member are pressed against the master by the contact / separation drive mechanism after the tip of the master is supported by the plate cylinder, both sides of the master pulled to the plate cylinder side by the rotation of the plate cylinder are pulled outward by the inclined roller. In this process, the elastic member presses the center of the master, so that even if the master is wrinkled or wavy, it is stretched flat. Further, since the master also passes through the elastic member when it passes through the inclined roller, a state where only the central portion is squeezed by the elastic member while both sides are released from the inclined roller is avoided.Furthermore, even if the rear end edge of the master is inclined or the master is transported in a skewed state, the pair of inclined rollers are simultaneously formed from the master immediately before the vicinity of the rear end of the master passes through the inclined rollers. Get away.
[0012]
According to a second aspect of the present invention, in the printing apparatus according to the first aspect, the elastic member is located at a position near the plate cylinder side from the line connecting the contact points of the inclined rollers to the master, and the width of the master. It arrange | positions in the position press-contacted to the center part of a direction. Therefore, even after passing through the elastic member that presses the center of the master, the master receives a tensile force on the outside by the inclined roller.
[0013]
According to a third aspect of the present invention, in the printing apparatus according to the first or second aspect, the inclined roller and the elastic member are disposed in the vicinity of the plate cylinder. Therefore, when the master passes through the inclined roller and the elastic member, the length of the portion that is not wound around the plate cylinder of the master is shortened, so that the master rampage at the moment when the master is released from the inclined roller and the elastic member is suppressed. .
[0014]
According to a fourth aspect of the present invention, in the printing apparatus according to the first, second, or third aspect, the contacting / separating drive mechanism is configured to cause the inclined roller and the elastic member to contact and separate from the master a plurality of times while the master is wound around the plate cylinder. An intermittent control means for controlling the operation is further provided. Therefore, when the master is wound around the plate cylinder, the inclined roller and the elastic member act as loads on the master, and tension is applied to the master between the inclined roller and the elastic member and the plate cylinder. Since the elastic member is given a time to release the load by intermittently separating from the master, even if there is a part that has locally extended, the state that the master has extended when released from the inclined roller and elastic member is the original Heal.
[0016]
  Claim5The invention described in claim 1, 2, 3Or 4In the printing apparatus described above, the image area determining means for determining the size of the image area, the pressure setting means for setting the pressure contact force of the inclined roller and the elastic member to the master according to the determination result of the image area determining means, and the pressure setting means And a controller that drives the contact / separation drive mechanism based on the setting result. Therefore, the strength of the waist of the master varies depending on the size of the image area, but the pressure contact force between the inclined roller and the elastic member is adjusted, so that abnormal elongation is prevented.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  Implementation of the present inventionFirst configuration example that is the premise of formWill be described with reference to FIGS. As shown in FIGS. 1 and 2, a plate cylinder 2 around which a master 1 that has been subjected to plate making is wound is rotatably provided. Around the plate cylinder 2, the master 1 is heated and punched to make a plate, the plate making section 3 for feeding the master 1 to the plate cylinder 2, and printing fed from a paper feed section (not shown). A pair of registration rollers 5 that transport the paper 4 wound around the plate cylinder 2 in synchronization with the progress of the master 1 and the printing paper 4 fed from the registration rollers 5 are pressed against the plate cylinder 2 via the master 1. A press roller 6, a peeling claw 7 for peeling the printed printing paper 4 from the plate cylinder 2, and a paper discharge unit 8 for storing the printing paper 4 peeled by the peeling claw 7 are arranged.
[0018]
The plate-making unit 3 includes a platen roller 10 that is rotationally driven along the conveyance path 9 of the master 1, a thermal head 11 that is supported so as to come into contact with the platen roller 10, a lower tension roller 12, A tension roller upper 13 that contacts the roller lower 12, a fixed blade 14, a movable blade 15 that cuts the master 1 together with the fixed blade 14, a pair of transport rollers 16 and 17, a guide plate 18 that supports the master 1 from below, and the like are sequentially arranged. It is formed by doing. The roll core 1a, the platen roller 10, the lower tension roller 12, the upper tension roller 13, the conveying rollers 16, 17 and the like of the master 1 are rotatably supported on a side plate (not shown) of the main body case of the printing apparatus.
[0019]
The thermal head 11 has innumerable heating elements arranged in the main scanning direction (a direction orthogonal to the conveyance direction of the master 1), and is pressed against the platen roller 10 by a biasing force of a spring (not shown). The tension roller lower 12 is driven at a higher peripheral speed than the platen roller 10 in order to apply tension to the master 1, but is connected to the drive unit via a torque limiter (not shown), so that the master 1 is excessive. Never pull on. Further, the transport rollers 16 and 17 are driven at a higher peripheral speed than the platen roller 10, and rotate while slipping with respect to the master 1 to apply a predetermined tension to the master 1.
[0020]
Accordingly, in the plate making unit 3, the master 1 is pulled out by driving the platen roller 10, the lower tension roller 12, the upper tension roller 13, and the conveying rollers 16, 17 by a stepping motor (not shown). Is driven, a perforation (dot) corresponding to the image is formed in the master 1.
[0021]
The plate cylinder 2 is obtained by winding a plurality of layers of mesh screens on the outer peripheral surface of a porous support cylindrical body composed of a non-opening portion 2a and an opening portion 2b. The mesh screen is a resin or metal net. The plate cylinder 2 has a flange (not shown) fixed at both ends thereof rotatably supported by an ink pipe 19 fixedly supported on a side plate of the printing apparatus, and is driven clockwise. An ink roller 20 and a doctor roller 21 that are in contact with the inner peripheral surface of the plate cylinder 2 are provided inside the plate cylinder 2 so as to be rotatable with a slight gap therebetween. The ink roller 20 and the doctor roller An ink reservoir 23 for receiving ink dropped from a supply hole 22 formed at the lower end of the ink pipe 19 is formed between the ink pipe 19 and the ink reservoir 19. Ink is supplied to the ink pipe 19 from an ink pack (not shown) provided outside the plate cylinder 2.
[0022]
Further, a shielding plate 25 having a notch 24 formed in a part of the outer periphery is fixed to the side surface of the plate cylinder 2. A sensor 26 is provided for detecting the rotational position of the plate cylinder 2 by detecting the rotational position of the shielding plate 25. The sensor 26 includes a light emitting element and a light receiving element. The sensor 26 is opened when the optical path between the two faces the notch 24, and the optical path is cut off when facing the part other than the notch 24. , A sensor for switching the detection signal from the light receiving element.
[0023]
Further, a stage 27 and a clamper 28 are attached to the outer peripheral surface of the plate cylinder 2 so as to sandwich the tip of the master 1 at the non-opening portion 2a. The stage 27 is formed of a magnetic material and has a length along the axial direction of the plate cylinder 2. The clamper 28 is rotatably supported by using a clamper shaft 29 disposed along the longitudinal direction of the stage 27 as a support shaft.
[0024]
The press roller 6 is formed by forming an elastic body in a cylindrical shape on a core metal. In this case, nitrile rubber or chloroprene rubber is used as the elastic body. The press roller 6 is rotatably supported at one end of a press roller arm 30 driven in a rotational direction by a cam (not shown) or the like, and can be brought into contact with and separated from the plate cylinder 2.
[0025]
An upper part of the plate cylinder 2 is provided with an arm shaft 31 parallel to the axis of the plate cylinder 2 so as to be rotatable at a fixed position. One end of a roller arm 32 is fixedly fitted to the arm shaft 31. ing. An inclined roller 33 is rotatably supported on both sides of the roller arm 32 on the rotating free end side, and an elastic member 34 is attached to a central portion of the roller arm 32. The inclined roller 33 is formed by forming a soft silicon rubber in a cylindrical shape on a core metal. The elastic member 34 is made of solid or sponge-like material such as silicon or chloroprene rubber.
[0026]
The inclined roller 33 is disposed at a position where the both sides of the master 1 in the width direction are pressed against each other, and rotates following the friction force with the master 1 pulled by the rotating plate cylinder 2. It rotates with the rotation center which inclines with respect to the width direction of the master 1 so that it may pull toward the outer side of the width direction. Specifically, this will be described with reference to FIGS. Although only one side is shown in these drawings, the inclined roller 33 has a cylindrical shape, but is inclined in a letter C shape in the direction of conveyance of the master 1 (the direction of the arrow in FIG. 5).
[0027]
As shown in FIG. 6, in the case of using a conical inclined roller 35 instead of the cylindrical inclined roller 33, the pair of inclined rollers 35 are gradually moved to the positions where both sides of the master 1 are pressed, and gradually toward the outside. It is possible to pull both sides of the master 1 outward by supporting the shaft center so as to be rotatable in an upwardly inclined state. The elastic member 34 described above is disposed on a substantially line connecting the contact points of the inclined rollers 33 (or 35) with the master 1.
[0028]
Further, an approach / separation drive mechanism 36 that selectively contacts and separates the inclined roller 33 (or 35) and the elastic member 34 with respect to the master 1 is provided. As shown in FIG. 3, the contact / separation drive mechanism 36 rotates the arm shaft 31 together with the roller arm 32 to bring the inclined roller 33 and the elastic member 34 into contact with and away from the master 1. 35) and a roller arm 32 having one end fixed to the arm shaft 31 supporting the elastic member 34, a lever 37 having one end fixed to the arm shaft 31, and a spring 38 for urging the other end of the lever 37 downward. And a solenoid 39 that rotates the lever 37 together with the arm shaft 31 and the roller arm 32 against the urging force of the spring 38 by excitation.
[0029]
In such a configuration, when a document is set in a document reading unit (not shown) and a start signal is output by pressing a start button or the like, the plate cylinder 2 is driven counterclockwise by a motor (not shown). In this process, the master 1 that has been wound around the plate cylinder 2 is peeled off and discarded by a plate discharging device (not shown), and the plate cylinder 2 is stopped when the clamper 28 reaches almost directly above. . At the time of this stop, the clamper 28 rotates in the opening direction around the clamper shaft 29 and is maintained in the plate feed standby state.
[0030]
When the original is sent to the original reading section and the image is read and the read image is formed on the CCD sensor, the image data (analog data) converted into an electric signal by the CCD sensor is digitally converted by the A / D converter. It is converted into data and output to the thermal head 11 via a plate making control device or the like. That is, the heating elements arranged in a line on the thermal head 11 are selectively energized based on the image data, and the platen roller 10, the lower tension roller 12, the upper tension roller 13, and the transport rollers 16, 17 are driven. Then, the master 1 is conveyed to the plate cylinder 2 side. As a result, dots are formed in the master 1 by punching based on the image data.
[0031]
At this time, it is determined that the tip of the master 1 has reached the clamper 28 by counting the number of steps of the stepping motor that drives the platen roller 10, the lower tension roller 12, the upper tension roller 13, and the transport rollers 16 and 17. The clamper 28 is closed by an opening / closing device (not shown), and the tip of the master 1 is held between the clamper 28 and the stage 27 on the plate cylinder 2. Subsequently, since the plate cylinder 2 is driven at a circumferential speed substantially equal to the conveyance speed of the master 1, the master 1 is wound around the outer circumference of the plate cylinder 2 as shown in FIG. 2.
[0032]
When winding of the master 1 around the plate cylinder 2 is started, the plate cylinder 2 further rotates clockwise, and the optical axis of the sensor 26 is blocked by the shielding plate 25 as shown in FIG. And the solenoid 39 is excited based on the detection signal. 3, the lever 37 rotates counterclockwise together with the arm shaft 31 and the roller arm 32, so that the inclined roller 33 (or 35) and the elastic member 34 press the master 1 against the guide plate 18. The inclined roller 33 (or 35) rotates following the friction with the master 1 drawn out by the plate cylinder 2, but the both sides of the master 1 are pulled outward due to the inclination of the shaft. Since the master 1 is pressed and squeezed, even if the master 1 is wrinkled or wavy, it is stretched flat.
[0033]
When it is determined that the plate making has been completed based on the number of steps of the stepping motor that drives the platen roller 10 and the like, power transmission to the platen roller 10, the lower tension roller 12, the upper tension roller 13, and the conveying rollers 16, 17 is performed. After being cut off, the movable blade 15 is driven to cut the master 1 together with the fixed blade 14. The rotation angle of the plate cylinder 2 when the rear end of the master 1 passes through the inclined roller 33 and the elastic member 34 is recognized by the sensor 26 detecting the rotation angle of the shielding plate 25, and the sensor 26 detects at this time. 3 is interrupted by the signal, the lever 37, the arm shaft 31, and the roller arm 32 are rotated clockwise by the biasing force of the spring 38. Thereby, the inclined roller 33 and the elastic member 34 are separated from the master 1.
[0034]
When the winding of the master 1 around the plate cylinder 2 is completed, the printing paper 4 that has reached the nip portion of the registration roller 5 from the paper feeding unit is fed by the rotation of the registration roller 5 and the printing paper is printed. When a state in which the paper 4 is fed to a predetermined position is detected by a paper sensor (not shown), the press roller arm 30 is pressed by the cam and pivots upward, so that the press roller 6 is attached to the plate cylinder 2. The printing paper 4 is pressed against the opening 2b. As a result, the master 1 adheres to the plate cylinder 2 and the ink is transferred to the printing paper 4, that is, printing is performed. The printed printing paper 4 is peeled from the plate cylinder 2 by the peeling claw 7 that advances to the plate cylinder 2 side, and is discharged to the paper discharge unit 8.
[0035]
In parallel with this operation, the platen roller 10, the lower tension roller 12, the upper tension roller 13, and the conveying rollers 16 and 17 are driven, and the new master 1 is pulled out until it reaches the nip portion of the conveying rollers 16 and 17, and the next plate making is performed. It is kept in a standby state in preparation for.
[0036]
As described above, in the process in which the master 1 is wound around the plate cylinder 2, the master 1 is pulled outward by the inclined roller 33 and is stretched flat by the elastic member 34 in this state. Since they are arranged on a straight line connecting the contact points of the pair of inclined rollers 33, the master 1 also passes through the elastic member 34 when it passes through the inclined rollers 33. That is, a state where only the central portion is squeezed by the elastic member 34 with both sides released from the inclined roller 33 is avoided. In other words, only when the master 1 is pulled to both sides by the pair of inclined rollers 33, the central portion of the master 1 is squeezed by the elastic member 34. Therefore, even when the master 1 having a low waist is used, the master 1 is stretched cleanly and flatly. be able to. As a result, the master 1 wound around the plate cylinder 2 is not wrinkled or wavy and can be printed beautifully. The above are the effects corresponding to the first aspect of the invention.
[0037]
  Next, the implementation of the present inventionSecond configuration example that is the premise of the formWill be described with reference to FIG.First configuration exampleThe same parts as those in FIG. BookConfiguration exampleOther followingConfiguration exampleThe same applies to. In FIG. 7, only one side is shown, but the elastic member 34 is located on the line connecting the contact points of the inclined rollers 33 with the master 1 in the direction opposite to the plate cylinder 2 side (arrow direction) and It arrange | positions in the position press-contacted to the center part of the width direction.
[0038]
In such a configuration, the master 1 receives an external tensile force by the inclined roller 33 even after passing through the elastic member 34 that presses the central portion thereof. That is, when the master 1 passes through the inclined roller 33, it has already passed through the elastic member 34. Therefore, since both sides of the rear end portion of the master 1 are released from the inclined roller 33, there is no state where only the central portion is squeezed by the elastic member 34. Thus, as in the prior art (see FIG. 10), Wrinkles can be prevented from occurring at the center of the master 1. This is an effect corresponding to the second aspect of the invention.
[0039]
  Next, the implementation of the present inventionThird example of configurationWill be described. If described with reference to FIG. 1 and FIG.Configuration exampleThen, the inclined roller 33 and the elastic member 34 are disposed in the vicinity of the plate cylinder 2.
[0040]
According to such a configuration, in the process of winding the master 1 around the plate cylinder 2, when the master 1 passes through the inclined roller 33 and the elastic member 34, the length of the portion of the master 1 that cannot be wound around the plate cylinder 2 is reduced. Shorter. Thereby, the rampage of the master 1 at the moment when it is released from the inclined roller 33 and the elastic member 34 is suppressed. As a result, the master 1 that has been flattened by the inclined roller 33 and the elastic member 34 can be quickly wound around the plate cylinder 2. Therefore, wrinkles and undulations of the master 1 on the plate cylinder 2 can be prevented. This is an effect corresponding to the third aspect of the invention.
[0041]
  Next, the implementation of the present inventionFourth configuration example that is the premise of formWill be described. BookConfiguration exampleIs an intermittent control means for controlling the operation of the contact / separation drive mechanism 36 (see FIG. 3) so that the inclined roller 33 and the elastic member 34 are contacted and separated from the master 1 a plurality of times while the master 1 is wound around the plate cylinder 2. (Not shown). Note that the transport length of the master 1 is recognized by the number of steps of the stepping motor that drives the platen roller 10 and the like as described above.Configuration exampleThe intermittent control means in FIG. 3 is a control means for performing an operation of temporarily shutting off the energization to the solenoid 39 shown in FIG. 3 when the number of steps reaches a predetermined number during the rotation of the stepping motor. However, the present invention is not limited to this as long as the solenoid 39 is driven intermittently.
[0042]
In such a configuration, when the master 1 is wound around the plate cylinder 2, the inclined roller 33 and the elastic member 34 act on the master 1 as loads, and between the inclined roller 33 and the elastic member 34 and the plate cylinder 2. Although tension is applied to the master 1, the solenoid 39 is driven intermittently, so that the inclined roller 33 and the elastic member 34 are intermittently separated from the master 1 to release the load. As a result, even if the master 1 has a locally extended portion, the extended state is restored when it is released from the inclined roller 33 and the elastic member 34, so that the master 1 is wound around the plate cylinder 2 in the fully extended state. There is nothing. Thereby, a read image can be output faithfully. This is an effect corresponding to the invention of claim 4.
[0043]
  next,Applicable to the first to fourth configuration examplesOf the present inventionOf the first implementationA form is demonstrated. In the present embodiment, the inclined roller 33 and the elastic member 34 are separated from the master 1 immediately before the rear end of the master 1 whose tip is supported by the plate cylinder 2 passes through the inclined roller 33 and the elastic member 34. Is further provided with a separation timing control means (not shown) for controlling the operation of the contact / separation drive mechanism 36 (see FIG. 3). The separation timing control means in the present embodiment is a state immediately before the rear end of the cut master 1 passes through the inclined roller 33 and the elastic member 34, and the stepping motor for driving the platen roller 10 and the like has a predetermined number of steps. The control means recognizes that the number of steps has been reached, and at the time of recognition, performs control to shut off the energization of the solenoid 39 shown in FIG. 3, but is not limited thereto.
[0044]
  In such a configuration, even if the cut rear end edge of the master 1 is inclined or the master 1 is transported in the skewed state, immediately before the vicinity of the rear end of the master 1 passes through the inclined roller 33, Are simultaneously separated from the master 1. Thereby, when the rear end portion of the master 1 passes through the inclined roller 33, the load of the inclined roller 33 does not act only on one side, and the load does not change from right to left. Therefore, it is possible to prevent the occurrence of wrinkles due to the slack of only one side of the master 1. Further, it is not necessary to strictly arrange the inclined rollers 33 that are paired on the left and right on a straight line that is orthogonal to the conveying direction of the master 1, so that the manufacturing can be facilitated..
[0045]
  Next, the present inventionSecond implementationA form is demonstrated based on FIG.8 and FIG.9. This example includes an image area determining means for determining the size of an image area, a pressure setting means for setting a pressure contact force of an inclined roller and an elastic member with respect to a master based on a determination result of the image area determining means, and setting of the pressure setting means The printing apparatus further includes a control unit that drives the contact / separation drive mechanism based on the result.
[0046]
In the present embodiment, the image area judging means for judging the size of the image area is formed in the master 1 from a read image (not shown) or from image data transferred from the outside and temporarily stored in the bitmap memory. It is a calculating part (not shown) which measures the number of perforations (dots). Further, the pressure setting means for setting the pressure contact force of the inclined roller 33 and the elastic member 34 with respect to the master 1 based on the determination result of the image area determining means corresponds to the number of perforations (dots) of the master 1 to be described later. It is the table which set the rotation angle. The control unit 40 shown in FIG. 9 has a function of driving a drive motor 42 of a contact / separation drive mechanism 43 described later based on the setting result of the pressure setting means (table). The control unit 40 is connected to a reading unit 41 that reads a document, the sensor 26 described above, and a drive motor 42 that can rotate forward and backward.
[0047]
The contact / separation drive mechanism 43 that selectively contacts and separates the inclined roller 33 and the elastic member 34 with respect to the master 1 rotates the arm shaft 31 together with the roller arm 32 as shown in FIG. The elastic member 34 is brought into contact with and separated from the master 1. The roller arm 32 which supports the inclined roller 33 and the elastic member 34 and has one end fixed to the arm shaft 31; the lever 37 whose one end is fixed to the arm shaft 31; A worm arm 45 having a worm 44 formed thereon and a rear end rotatably supported by the arm shaft 31; a worm wheel 46 directly connected to the drive motor 42 and meshed with the worm 44; the worm arm 45 and the lever 37; And a spring 47 stretched between them. The worm arm 45 is formed with a bent piece 45a that presses the lever 37 during a clockwise rotation operation.
[0048]
Such a contact / separation drive mechanism 43 is configured to be driven by the control unit 40 based on the setting result of the pressure setting means. Specifically, the rotation angle of the drive motor 42 when the inclined roller 33 and the elastic member 34 are pressed against the master 1 is controlled by the size of the image area.
[0049]
In such a configuration, as described in the previous embodiment, when it is determined that the tip of the master 1 has reached the clamper 28, the clamper 28 is closed by an unillustrated opening / closing device, and the tip of the master 1 is connected to the clamper 28. It is held between the stage 27 on the plate cylinder 2. Subsequently, since the plate cylinder 2 is driven at a circumferential speed substantially equal to the conveyance speed of the master 1, the master 1 is wound around the outer circumference of the plate cylinder 2 as shown in FIG. 2.
[0050]
When winding of the master 1 around the plate cylinder 2 is started, the plate cylinder 2 further rotates clockwise, and the optical axis of the sensor 26 is blocked by the shielding plate 25 as shown in FIG. The control unit 40 drives the drive motor 42 in one direction based on the detection signal. In this case, in FIG. 8, the worm arm 45 rotates counterclockwise about the arm shaft 31 and pulls the spring 47, so that the lever 37 rotates counterclockwise together with the arm shaft 31 and the roller arm 32. Thereby, the inclined roller 33 and the elastic member 34 press the master 1 against the guide plate 18. The actions of the inclined roller 33 and the elastic member 34 are the same as described in the previous embodiment.
[0051]
In addition, the timing when the rear end of the master 1 wound around the plate cylinder 2 passes through the inclined roller 33 is recognized by the sensor 26 detecting the rotation angle of the shielding plate 25 as described above. When the control unit 40 sometimes drives the drive motor 42 in the opposite direction, the worm arm 45 rotates clockwise in FIG. 8 and presses the lever 37 with the bent piece 45a formed in a part thereof. Rotates together with the arm shaft 31 and the roller arm 32 in the clockwise direction. Thereby, the inclined roller 33 and the elastic member 34 are separated from the master 1.
[0052]
By the way, the rotation angle of the worm arm 45 in the counterclockwise direction can be changed by controlling the rotation angle of the drive motor 42, thereby adjusting the pressure contact force of the inclined roller 33 and the elastic member 34 to the master 1. Is done. In this embodiment, the size of the image area is determined by the image area determination means, and the pressure contact force of the inclined roller 33 and the elastic member 34 with respect to the master 1 is set by the pressure setting means based on the determination result of the image area determination means. Since the control unit 40 drives the drive motor 42 of the contact / separation drive mechanism 43 based on the setting result, the strength of the waist of the master 1 changes depending on the size of the image area, but the inclined roller 33 and the elastic member 34. Since the pressure contact force is adjusted, abnormal elongation can be prevented. Thereby, an image can be output faithfully.
[0053]
【The invention's effect】
  According to the first aspect of the present invention, the apparatus includes a pair of conveyance rollers disposed immediately before the plate cylinder along the conveyance path of the master toward the plate cylinder, and downstream of the conveyance roller along the conveyance path of the master. By rotating at a rotation center that is inclined with respect to the width direction of the master by a frictional force with the master that is disposed on the side and presses both sides in the width direction of the master and is pulled by the rotating plate cylinder A pair of inclined rollers for pulling the master toward the outer side in the width direction, and a contact point of the inclined roller with respect to the master on the downstream side of the conveying roller along the conveying path of the master. An elastic member disposed at a position that does not approach the plate cylinder side from the vicinity on the connecting line and that is pressed against the center in the width direction of the master; Since the elastic member is provided with a contact / separation drive mechanism that selectively contacts and separates the master, both ends of the master are supported by the plate cylinder and pulled toward the plate cylinder by the rotation of the plate cylinder. The elastic member is pulled outward by the inclined roller, and the elastic member presses the central portion of the master in this process, so that even when the master is wrinkled or wavy, it can be stretched flat. In particular, since the master also passes through the elastic member when it passes through the inclined roller, it is possible to avoid a state in which only the central portion is squeezed by the elastic member while both sides near the rear end are released from the inclined roller. As a result, wrinkles and undulations do not occur even in the central portion near the rear end of the master, and clean printing can be performed.Further, immediately before the rear end of the master whose front end is supported by the plate cylinder passes through the inclined roller and the elastic member, the separation mechanism that controls the operation of the contact / separation driving mechanism to separate the inclined roller and the elastic member from the master. Since the timing control means is further provided, even if the cut rear end edge of the master is inclined or the master is transported in the skewed state, immediately before the vicinity of the rear end of the master passes the inclined roller, Can be separated from the master at the same time. Thereby, when the rear end portion of the master passes through the inclined roller, the load of the inclined roller does not act only on one side, and the load does not change from right to left. Therefore, it is possible to prevent the generation of wrinkles due to the slack of only one side of the master. In addition, since it is not necessary to strictly arrange the inclined rollers that are paired on the left and right on a straight line perpendicular to the conveyance direction of the master, manufacturing can be facilitated.
[0054]
According to the second aspect of the present invention, the elastic member is pressed against the central portion in the width direction of the master at a position near the plate cylinder side from the line connecting the contact points of the inclined rollers to the master. Therefore, even after passing through the elastic member that presses the center of the master, the master receives a tensile force outside by the inclined roller. Therefore, there is no state where only the central portion is rubbed by the elastic member even though both sides of the rear end portion of the master are released from the inclined rollers, so that the wrinkles at the central portion of the master are eliminated. Occurrence can be prevented.
[0055]
According to the invention described in claim 3, since the inclined roller and the elastic member are arranged in the vicinity of the plate cylinder, when the master passes through the inclined roller and the elastic member, it is not wound around the plate cylinder of the master. Since the length of the portion is shortened, the master rampage at the moment when it is released from the inclined roller and the elastic member can be suppressed. Accordingly, the master can be wound around the plate cylinder in a state where the master is flattened by the inclined roller and the elastic member from the front end to the vicinity of the rear end.
[0056]
According to a fourth aspect of the present invention, there is further provided intermittent control means for controlling the operation of the contact / separation drive mechanism so that the inclined roller and the elastic member are contacted / separated a plurality of times while the master is wound around the plate cylinder. Therefore, when the master is wound around the plate cylinder, the inclined roller and the elastic member act as loads on the master, and tension is applied to the master between the inclined roller and the elastic member and the plate cylinder. Since the elastic member is given a time to release the load by intermittently separating from the master, even if there is a part that has locally extended, the state that the master has extended when released from the inclined roller and elastic member is the original Heal. Therefore, an image can be output faithfully.
[0058]
  Claim5The described invention includes an image area determination unit that determines the size of an image area, a pressure setting unit that sets a pressure contact force of an inclined roller and an elastic member with respect to a master based on a determination result of the image area determination unit, and And a control unit that drives the contact / separation drive mechanism based on the setting result, so that the strength of the waist changes depending on the image area, but the pressure contact force of the inclined roller and the elastic member is adjusted. Therefore, abnormal elongation can be prevented. Therefore, an image can be output faithfully.
[Brief description of the drawings]
FIG. 1 shows the implementation of the present invention.First configuration example that is the premise of formFIG. 2 is a front view showing a part of the printing apparatus in FIG.
FIG. 2 is a front view showing a process of winding a master around a plate cylinder with a part in cross section.
FIG. 3 is a front view showing a configuration of a contact / separation drive mechanism.
FIG. 4 is an explanatory view of a relationship between an inclined roller and an elastic member as viewed from the bottom surface side.
FIG. 5 is a plan view showing a pressure contact position of an inclined roller and an elastic member with respect to a master.
FIG. 6 is a plan view showing a pressure contact position with respect to a master of an inclined roller and an elastic member as a modified example.
FIG. 7 shows the implementation of the present invention.Second configuration example that is the premise of the formIt is a top view which shows the press contact position with respect to the inclination roller and elastic member in a 2nd form.
FIG. 8 shows the first embodiment of the present invention.twoIt is a front view which shows the contact-separation drive mechanism in the form.
FIG. 9 is a block diagram of an electronic circuit.
FIG. 10 is a plan view showing a pressure contact position of a conventional inclined roller and an elastic member with respect to a master.
[Explanation of symbols]
  1 Master
  2 Version cylinder
  4 Printing paper
  33 inclined roller
  34 Elastic members
  36 Contact / separation drive mechanism
  40 Control unit
  43 Contact / separation drive mechanism

Claims (5)

Wrapping the pre-printed master around the plate cylinder, aligning the position with the master, feeding the printing paper to the outer periphery of the plate cylinder, pressing the printing paper against the plate cylinder via the master, In a printing apparatus that prints an image on the printing paper by transferring ink from the master that has been made to the printing paper to the printing paper,
A pair of transport rollers disposed immediately before the plate cylinder along the transport path of the master toward the plate cylinder;
It is disposed at a position downstream of the transport roller along the transport path of the master and presses both sides in the width direction of the master, and is caused by frictional force with the master pulled by the rotating plate cylinder. A pair of inclined rollers for pulling the master toward the outer side in the width direction by rotating with a rotation center inclined with respect to the width direction;
A center in the width direction of the master that is downstream of the transport roller along the transport path of the master and is not close to the plate cylinder side from the vicinity of the line connecting the contact points of the inclined rollers to the master An elastic member disposed at a position pressed against the part;
A contact / separation drive mechanism that selectively contacts and separates the inclined roller and the elastic member with respect to the master;
The separation timing for controlling the operation of the contact / separation driving mechanism so that the inclined roller and the elastic member are separated from the master immediately before the rear end of the master whose tip is supported by the plate cylinder passes through the inclined roller and the elastic member. Control means;
A printing apparatus comprising:   The elastic member is disposed at a position close to a direction opposite to the plate cylinder side from a line connecting contact points of the inclined rollers with respect to the master, and at a position where the elastic member is pressed against the central portion in the width direction of the master. The printing apparatus according to claim 1.   The printing apparatus according to claim 1, wherein the inclined roller and the elastic member are disposed in the vicinity of the plate cylinder.   2. An intermittent control means for controlling the operation of the contact / separation drive mechanism so that the inclined roller and the elastic member are brought into contact with and separated from the master a plurality of times while the master is wound around the plate cylinder. , 2 or 3 printing apparatus. Based on the image area determination means for determining the size of the image area, the pressure setting means for setting the pressure contact force of the inclined roller and the elastic member to the master based on the determination result of the image area determination means, printing apparatus according to claim 1, 2, 3 or 4, wherein the further comprising a control unit for driving the separation driving mechanism.

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