JP4608283B2 - Stencil printing machine - Google Patents

Description

  The present invention relates to a stencil printing apparatus that performs thermal perforation plate-making with a thermal head on a master, and more particularly to an image processing apparatus of the stencil printing apparatus.

  Conventionally, digital thermal stencil printing is known as a simple printing method. This is because a master having a thermoplastic resin film and a porous support bonded to each other is brought into contact with a thermal head in which fine heating elements are arranged in a row, and the master is platen while energizing the heating elements in a pulsed manner. A perforated image based on image information is formed on a thermoplastic resin film of a master by hot melt perforation by carrying it with a conveying means such as a roller, and then the perforated master is wound around a porous cylindrical plate cylinder. Then, by pressing the paper against the outer peripheral surface of the plate cylinder by the pressing means, the ink exuded from the opening portion of the plate cylinder and the perforation portion of the master is transferred to the paper to obtain a printed image.

  In this stencil printing apparatus, it is known to perform image processing such as filter processing, shading processing, scaling processing, and binarization processing on a read original image. Image processing is performed to perform these image processing. Dedicated ASIC (specific application IC) is used. An example of such an image processing apparatus is disclosed in, for example, “Patent Document 1”.

JP 2004-237472 A

  By using ASIC for image processing, image processing specialized for product specifications can be performed. However, since the ASIC is hardware, the specification cannot be changed after creation. For example, it is not possible to change the specification of the four-sided aggregated functional specification to the eight-sided integrated in accordance with the user's needs.

  On the other hand, it is conceivable to use a DSP (digital signal processor) for the control unit. However, since the DSP has a configuration that is more versatile than the ASIC, not all necessary processes are completed within the working time of the apparatus. Therefore, it is necessary to perform parallel processing by arranging them in parallel. However, this has a problem that the cost is increased because a plurality of DSPs are used, and a layout of the control unit is restricted by the plurality of DSPs.

  The present invention solves the above-described problems, and provides a stencil printing apparatus having an image processing control unit capable of changing specifications in accordance with user needs without increasing costs and without being restricted by layout. Objective.

According to the first aspect of the present invention, an image reading unit that reads an original image, a plate making unit having a thermal head that performs perforating plate making on a master, and image data read by the image reading unit are processed, and then the thermal head is An image processing unit that outputs the processed image data to a thermal head driving unit that drives the plate, a plate cylinder on which the master that has been subjected to platemaking is wound, and a pressing unit that presses a sheet against the outer peripheral surface of the plate cylinder; in the stencil printing device equipped with the image processing unit have a single digital signal processor capable of rewriting a program, an image processing said digital signal processor at the time of plate making to the master by the thermal head And the pixel density conversion is performed to process only the necessary number of pixels, and the resolution of the thermal head is lower than the resolution of the image data. When the digital signal processing processor and performing pixel density conversion corresponding to the resolution of the thermal head.

  According to the present invention, since image processing is performed by an image processing unit having a single digital signal processing processor, image processing is performed by an image processing unit configured without increasing costs and without being restricted by layout. The cost reduction of the apparatus can be achieved, and the design and configuration can be simplified. In addition, since the digital signal processor has a software processing unit, it is possible to change specifications according to user needs, improve usability, and implement the latest image processing in a timely manner. It can be installed.

  FIG. 1 shows a stencil printing apparatus adopting an embodiment of the present invention. In FIG. 1, a stencil printing apparatus 1 includes a printing unit 2, a plate making unit 3, a paper feeding unit 4, a plate discharging unit 5, a paper discharging unit 6, an image reading unit 7, and the like.

The printing unit 2 disposed almost at the center of the apparatus main body 8 includes a plate cylinder 9 and a press roller 10 as pressing means.
The plate cylinder 10 is rotatably supported by a support shaft 11 that also serves as an ink supply pipe. The plate cylinder 10 is rotationally driven by a plate cylinder driving unit (not shown) and is detachable from the apparatus main body 8. An ink supply means 14 having an ink roller 12, a doctor roller 13, etc. is disposed inside the plate cylinder 9, and a clamper 15 that holds the tip of the master is attached to the outer peripheral surface of the plate cylinder 9 so as to be freely opened and closed. It has been.

  Below the plate cylinder 9 is disposed a press roller 10 whose both ends are rotatably supported by a pair of arm members (not shown). When the pair of arm members are swung by a swinging means (not shown), the press roller 10 is separated from the circumferential position of the plate cylinder 9 indicated by a solid line in FIG. 1 and the plate cylinder 9 indicated by a broken line. It selectively occupies a pressure contact position where pressure contact is made with a predetermined pressure contact force.

  A plate making unit 3 is disposed in the upper right part of the apparatus main body 8. The plate making unit 3 includes a master holding member 16, a platen roller 17, a thermal head 18, a master cutting means 19, a master conveying roller pair 20, 21 and the like.

  The master holding member 16 is attached to a side plate (not shown) of the apparatus main body 8, and a core of a master roll 22a formed by winding a master 22 formed by laminating a thermoplastic resin film and a porous support in a roll shape. Both ends of the portion 22b are supported rotatably and detachably.

  A platen roller 17 disposed on the left side of the master holding member 16 is rotatably supported on a side plate (not shown) of the apparatus body 8 and is driven to rotate by a stepping motor 23. A thermal head 18 positioned below the platen roller 17 and having a large number of heat generating elements is attached to a side plate (not shown) of the apparatus main body 8, and the surface of the heat generating elements is surrounded by a biasing force of a biasing means (not shown). It is pressed against the surface. The thermal head 18 selectively heats each heating element while contacting the surface of the thermoplastic resin film of the master 22, and performs hot melt perforation for the master 22. The operation of the thermal head 18 is controlled by a thermal head driving means 79 (see FIG. 3).

  Master cutting means 19 is disposed on the left side of the platen roller 17 and the thermal head 18. The master cutting means 19 having a fixed blade 19a fixed to a frame (not shown) of the apparatus main body 8 and a movable blade 19b supported so as to be movable with respect to the fixed blade 19a has a movable blade 19b with respect to the fixed blade 19a. This is a known configuration in which the master 22 is cut by rotating or moving up and down.

  On the left side of the master cutting means 19, a master transport roller pair 20, 21 is disposed. Each of the master conveying roller pairs 20 and 21 has a driving roller and a driven roller that are rotatably supported by a side plate (not shown) of the apparatus main body 8, and each driving roller is driven by a platen roller 17 by a driving means (not shown). The driven rollers are pressed against the corresponding driving rollers by urging means (not shown).

A sheet feeding unit 4 is disposed below the plate making unit 3. The paper feed unit 4 includes a paper feed tray 24, a paper feed roller 25, a separation roller pair 26, a registration roller pair 27, and the like.
A sheet feeding tray 24 on which a large number of sheets P can be stacked on the upper surface is supported by the apparatus main body 8 so as to be movable up and down, and is moved up and down by lifting means (not shown). A pair of side fences 28 that are movable in the paper width direction perpendicular to the paper transport direction are disposed on the upper surface of the paper feed tray 24 on which A3 size paper P can be placed vertically.

  Above the left end of the paper feed tray 24, a paper feed roller 25 having a high friction resistance member on the surface is disposed. The paper feed roller 25 is rotatably supported by a bracket (not shown) that is swingably supported by the apparatus main body 8. When the paper feed tray 24 is lifted by a lifting / lowering means (not shown), it is supplied with a predetermined pressure contact force. The uppermost sheet P on the paper tray 24 is pressed against. The paper feed roller 25 is rotationally driven by a paper feed drive means (not shown).

  On the left side of the paper feed roller 25, a separation roller pair 26 is disposed which includes an upper roller 26a and a lower roller 26b each having a high friction resistance member on the surface. The upper roller 26a is drivingly connected to the paper feed roller 25 via a driving force transmission means such as a gear or a belt, and is driven to rotate in the same direction in synchronism with the rotation of the paper feed roller 25. The lower roller 26b is pressed against the upper roller 26a with a predetermined pressing force by a biasing force of a biasing means (not shown), and is configured to be rotatable only in the same direction as the upper roller 26a.

  A registration roller pair 27 is disposed on the left side of the separation roller pair 26. The registration roller pair 27 including the driving roller 27a and the driven roller 27b transmits the rotational driving force from a plate cylinder driving unit (not shown) by a driving force transmission member (not shown) such as a gear and a cam, so that the driving roller 27a is connected to the plate. The sheet P is rotated toward the printing unit 2 at a predetermined timing by a driven roller 27b that rotates at a predetermined timing synchronized with the cylinder 9 and is in pressure contact with the driving roller 27a.

A plate discharging unit 5 is disposed on the upper left side of the printing unit 2. The plate removal unit 5 includes an upper plate removal member 29, a lower plate removal member 30, a plate removal box 31, a compression plate 32, and the like.
The upper plate removal member 29 has a drive roller 33, a driven roller 34, an endless belt 35, and the like. When the drive roller 33 is driven to rotate in the clockwise direction in the drawing by a plate discharge drive means (not shown), the endless belt 35 is shown in the drawing. Move in the direction of the arrow. The lower plate removal member 30 also has a drive roller 36, a driven roller 37, and an endless belt 38. The drive force of a plate discharge drive means (not shown) is transmitted by a drive force transmission means (not shown) such as a gear or a belt. When the roller 36 is rotationally driven in the counterclockwise direction in the figure, the endless belt 38 moves in the direction of the arrow in the figure. The lower plate removal member 30 is configured to be movable by a moving means (not shown), and a position shown in the figure and a position where the endless belt 38 positioned on the outer peripheral surface of the driven roller 37 abuts on the outer peripheral surface of the plate cylinder 9. Selectively occupy.

  The plate removal box 31 for storing the used master therein is configured to be detachable from the apparatus main body 8. A compression plate 32 for pushing the used master carried by the upper plate removal member 29 and the lower plate removal member 30 into the plate release box 31 is supported by the apparatus body 8 so as to be movable up and down, and is moved up and down by a lifting means (not shown). The

A paper discharge unit 6 is disposed below the plate discharge unit 5. The paper discharge unit 6 includes a peeling claw 39, a paper discharge conveying member 40, a paper discharge tray 41, and the like.
The base end of the peeling claw 39 is swingably supported by the apparatus body 8, and the free end formed at an acute angle by a claw swinging means (not shown) is close to the outer peripheral surface of the plate cylinder 9. It selectively occupies a proximity position shown and a separation position separated from the outer peripheral surface of the plate cylinder 9 in order to avoid an obstacle such as the clamper 15.

  The paper discharge conveying member 40 disposed on the lower left side of the peeling claw 39 includes a driving roller 42, a driven roller 43, an endless belt 44, a suction fan 45, and the like. The driving roller 42 is rotatably supported by a unit main body (not shown) and is driven to rotate by a paper discharge driving means (not shown). The driven roller 43 is also rotatably supported by a unit main body (not shown), and an endless belt 44 having a plurality of openings is stretched between the rollers 42 and 43. A suction fan 45 having a negative pressure in the inside of the unit main body (not shown) in the form of a casing is disposed in a lower portion of the unit main body (not shown) and located between the rollers 42 and 43. The paper discharge conveying member 40 sucks the paper P onto the endless belt 44 by the suction force of the suction fan 45 and transports the paper P in the direction of the arrow by the rotation of the driving roller 42.

  A paper discharge tray 41 for stacking the paper P conveyed by the paper discharge conveying member 40 on its upper surface moves on the paper stacking surface to one end fence 46 movable in the paper conveyance direction and in the paper width direction. It has a pair of free side fences 47.

  An image reading unit 7 is disposed on the upper part of the apparatus main body 8. The image reading unit 7 includes an original receiving tray 48 on which an original is stacked, a contact glass 49 on which an original is stacked, an original conveying roller pair 50 and an original conveying roller 51 for conveying an original, and guide plates 52 and 53 for guiding the original to be conveyed. A plurality of document conveying belts 54 for conveying the document along the contact glass 49, a document tray 83 for discharging the read document, and the above members except for the contact glass 49, and supporting and contacting the contact glass 49. A pressure plate 55 provided on the surface, reflection mirrors 56 and 57 for scanning and reading a document image, a fluorescent lamp 58, a lens 59 for focusing the scanned document image, an image sensor 60 such as a CCD for processing the focused image, and the like. Have. The image processed by the image sensor 60 is sent to an image processing unit described later as image data.

  FIG. 2 shows an operation panel of the stencil printing apparatus 1. An operation panel 61 disposed on the upper front surface of the apparatus body 8 has a plate making start key 62, a printing start key 63, a test printing key 64, a continuous key 65, a clear / stop key 66, a numeric key 67, and an enter key 68 on the upper surface. , A program key 69, a mode clear key 70, a printing speed setting key 71, a four-direction key 72, a display device 73 including a 7-segment LED, a display device 74 including an LCD, and the like. Selection setting keys 75, 76, 77, 78 are arranged below the display device 74. By pressing these keys, the display on the display device 74 is switched as appropriate, and the plate making mode, paper type, image position adjustment, etc. In addition to the above various settings, various image processing such as scaling, aggregation, and composition can be performed.

  FIG. 3 shows a block diagram of control means used in the stencil printing apparatus 1. In the figure, the control means 80 is a well-known microcomputer having a CPU, ROM, RAM, etc., not shown, and is provided inside the apparatus main body 8. The control unit 80 is provided with an image processing unit 81 that processes the image data sent from the image sensor 60 and then outputs the processed image data to the thermal head driving unit 79. As shown in FIG. 4, the image processing unit 81 used in the present embodiment includes a plurality of hardware 82a and 82b, a plurality of memories 82c, 82d, 82e, and 82f, a software processing unit 82g, and the like. One digital signal processor (DSP) 82 is included.

Based on the above configuration, the operation of the stencil printing apparatus 1 will be described below.
After the original is placed on the contact glass 49 by the operator, when the plate making start key 62 is pressed in a state where the pressure plate 55 is closed, the image reading unit 7 performs an original image reading operation. Reading of the image is performed by reflecting the reflected light exposed by the fluorescent lamp 58 by the reflecting mirrors 56 and 57, and the read image is converged by the lens 59 and then sequentially incident on the image sensor 60. The The image sensor 60 processes the sent image and then sends it to the image processing unit 81 as image data. In the image processing unit 81, the digital signal processor 82 performs image processing set in advance by pressing the selection setting keys 75 to 78. Image processing is performed based on the program. The processed image data is sequentially output to the thermal head driving unit 79. When a document is placed on the document receiving table 48, when the plate making start key 62 is pressed, the document transport roller pair 50 and the document transport belt 54 are operated so that one document is transported onto the contact glass 49 and is described above. The image is read in the same manner as described above. The document whose image has been read is transported by the document transport belt 54 and the document transport roller 51 and discharged onto the document tray 83.

  In parallel with the image reading operation in the image reading unit 7, the plate discharging unit 5 performs a plate discharging operation for peeling the used master from the outer peripheral surface of the plate cylinder 9. When the plate making start key 62 is pressed, the plate cylinder 9 starts rotating, and the tip of the used master on the outer peripheral surface thereof is at a predetermined plate discharging position corresponding to the endless belt 38 positioned on the outer peripheral surface of the driven roller 37. When reaching, the rotation of the plate cylinder 9 is stopped. Thereafter, the driving means and the moving means are operated to rotate the driving rollers 33 and 36, and the lower plate removal member 30 moves to the plate cylinder 9 side. When the endless belt 38 positioned on the outer peripheral surface of the driven roller 37 comes into contact with the used master, the plate cylinder 9 rotates again, and the used master that has been scooped up against the endless belt 38 comes into contact with the upper plate discharging member 29 and the lower plate. It is sandwiched between the plate removal member 30 and peeled off from the outer peripheral surface of the plate cylinder 10. The peeled used master is transported by each of the plate release members 29 and 30 and discarded in the plate release box 31, and then compressed by the compression plate 32. Even after all used masters are peeled from the outer peripheral surface, the plate cylinder 9 continues to rotate, rotates to a predetermined plate supply standby position, and stops. When the plate cylinder 9 stops at the plate feeding standby position, the opening / closing means is operated to open the clamper 15, and the stencil printing apparatus 1 enters the plate feeding standby state.

  When the plate removal operation is completed and the stencil printing apparatus 1 enters the plate feeding standby state, the platen roller 17 and each of the master transport roller pairs 20 and 21 are driven to rotate, and the master 22 is pulled out from the master roll 22a. When the image forming area of the master 22 reaches a position corresponding to each heating element of the thermal head 18, the thermal head driving unit 79 sets each heating element of the thermal head 18 based on the image data sent from the image sensor 60. By selectively generating heat, a plate-making image is formed on the surface of the thermoplastic resin film of the master 22. The master 25 is sent to the clamper 15 while making a plate, and when the tip of the master 25 reaches a predetermined position that can be held by the clamper 15, the clamper 15 is closed. Held on.

  Thereafter, the plate cylinder 9 is rotationally driven at the same peripheral speed as the conveying speed of the master 22, and the winding operation of the master 22 around the plate cylinder 9 is performed. When the image data signal sent from the image processing unit 81 is interrupted, the operation of the thermal head 18 is stopped, and when the master 22 for one plate is made, the platen roller 17 and the master transport roller pairs 20 and 21 The operation is stopped and the movable blade 19b is operated to cut the master 22. The cut master 22 is pulled out from the plate making section 3 by the rotation of the plate cylinder 9, and the plate cylinder 9 rotates to the home position and stops, thereby completing the plate making operation and the plate feeding operation.

  The printing operation is performed following the plate feeding operation. When the plate cylinder 9 stops at the home position, the sheet feed roller 25, the upper roller 26a, the drive roller 42, and the suction fan 45 are driven, and the plate cylinder 9 starts rotating at a low speed and is loaded on the sheet feed tray 24. The topmost sheet of the sheet P is pulled out, and its leading end is sandwiched between the registration roller pair 27. Then, the driving roller 27a is rotationally driven at a predetermined timing when the leading end of the image area in the plate cylinder rotation direction of the master 22 wound around the plate cylinder 9 reaches the contact portion with the press roller 10, and the drawn paper P Is fed between the plate cylinder 9 and the press roller 10. Almost simultaneously with the rotation of the driving roller 27a, the press roller 10 presses the peripheral surface thereof against the outer peripheral surface of the plate cylinder 9 by the operation of the swinging means, and the fed paper P is applied to the master 22 wound around the plate cylinder 9. Press contact. By this pressing operation, the press roller 10, the paper P, the master 22, and the plate cylinder 9 are pressed against each other, and the ink supplied to the inner peripheral surface of the plate cylinder 9 by the ink roller 12 oozes out from the opening portion of the plate cylinder 9, After the porous support of the master 22 is filled, it is transferred to the paper P through the perforated portion of the master 22 and so-called printing is performed.

  The sheet P to which the image has been transferred by printing is peeled off from the outer peripheral surface of the plate cylinder 9 by the peeling claw 39, falls downward, and is sent to the paper discharge conveying member 40. The paper P sent to the paper transport member 40 is transported to the left while being sucked to the upper surface of the endless belt 44 by the suction force of the suction fan 45, and discharged onto the paper discharge tray 41. Thereafter, the plate cylinder 9 rotates again to the home position and stops, and the stencil printing apparatus 1 enters a printing standby state after finishing the plate attaching operation.

  After the stencil printing apparatus 1 is in a print standby state, when printing conditions are input by various keys on the operation panel 61 and the trial printing key 64 is pressed, the plate cylinder 9 rotates at a higher speed than at the time of printing. While being driven, only one sheet P is fed from the sheet feeding unit 4 and a test printing is performed in the same manner as at the time of printing. When the image position or image density is confirmed by the trial printing, and the print start key 63 is pressed after the number of prints is input by the ten key 67, the paper P is continuously fed from the paper supply unit 4 and the trial printing is performed. The printing operation is performed in the same way as the time. When the set number of prints is consumed, the plate cylinder 9 stops at the home position, and the stencil printing apparatus 1 enters the print standby state again.

  In the above-described image reading operation and plate making operation, image processing is performed with a configuration in which the single DSP 82 is provided in the image processing unit 81 in the present embodiment, so that the cost is not increased and the layout is not restricted. Image processing can be performed by the configured image processing unit 81, and the cost reduction of the apparatus can be achieved, and the design and configuration can be simplified. Image processing by this single DSP 82 is impossible in other multi-function peripherals (devices with printers, facsimiles, and copying functions) because the processing time required by the device does not fall within the working time range. However, the stencil printing apparatus requires a plate making process in which the read image data is sequentially made by a thermal head, and the work time in this process is slower than the work time in the multifunction machine (A3 vertical). The processing can be performed in about 18 seconds).

  Further, the conventional apparatus employs an image processing unit having an application specific IC (ASIC) 84 as shown in FIG. Since the ASIC 84 has dedicated hardware 84a to 84e, a command register 84f, and memories 84g to 84j to which various image processing such as filter processing and scaling processing are assigned, specifications for various image processing are provided. Cannot be changed (for example, the maximum value of the scaling factor is changed from 400% to 600%). On the other hand, since the DSP 82 has the software processing unit 82g, the specifications of the image processing can be changed, and the design can be changed according to the user's needs, so that the usability is improved. Can do. Further, by changing the contents of the software processing unit 82g, the latest image processing can be mounted on the actual machine in a timely manner.

  In the above embodiment, the resolution of the image data read by the image reading unit 7 may be different from the resolution of the plate-making image made by the plate-making unit 3. For example, if the resolution of the image data is 600 dpi and the resolution of the prepress image is 400 dpi and A4 size longitudinal image data is processed, 7016 pixels must be processed during 600 dpi processing, but 400 dpi processing is required. In some cases, 4777 pixels are sufficient. In such a case, as shown in FIG. 6, for example, by performing pixel density conversion after performing filter processing and scaling processing, the time required for binarization processing is reduced from the time of 7016 pixel processing to 4777 pixel processing. Since the time is shortened, the reduced time can be allocated to other processing, and the image processing capability can be improved.

1 is a schematic front view of a stencil printing apparatus adopting an embodiment of the present invention. It is the schematic of the operation panel used for one Embodiment of this invention. It is a block diagram of the control means used for one Embodiment of this invention. It is the schematic explaining the image processing part used for one Embodiment of this invention. It is the schematic explaining the conventional image processing part. It is a figure for demonstrating the processing operation in the modification of one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 3 Plate making part 7 Image reading part 9 Plate cylinder 10 Pressing means (press roller)
DESCRIPTION OF SYMBOLS 18 Thermal head 22 Master 79 Thermal head drive means 81 Image processing part 82 Digital signal processor (DSP)
P paper

Claims (1)

An image reading unit for reading a document image, a plate making unit having a thermal head for perforating plate making on a master, and thermal head driving means for driving the thermal head after processing image data read by the image reading unit In the stencil printing apparatus, comprising: an image processing unit that outputs the image data after processing; a plate cylinder around which the master that has been subjected to platemaking is wound; and a pressing unit that presses a sheet against an outer peripheral surface of the plate cylinder,
Wherein the image processing unit have a single digital signal processor capable of rewriting a program, the digital signal processing processor performs pixel density conversion performs image processing upon plate making to the master by the thermal head The digital stencil performs pixel density conversion corresponding to the resolution of the thermal head when the required number of pixels are processed and the resolution of the thermal head is lower than the resolution of the image data. Printing device.

Images