JP4339039B2 - Stencil printing machine - Google Patents

Description

  The present invention relates to a stencil printing apparatus that transfers a printing paper while applying a printing pressure to a rotating drum and performs image transfer, and in particular, prints by instantaneously blowing a separating strong wind to peel off the printing paper from the drum. The present invention relates to an apparatus for peeling paper from a drum.

  This type of stencil printing apparatus includes a scanner unit that reads image data of a document to be printed, a plate making unit that punches a stencil sheet based on image data read by the scanner unit, and a stencil sheet produced by the plate making unit. A printing unit that transports printing paper while applying printing pressure to the rotating drum and transfers the image to the printing paper, a paper feeding unit that feeds the printing paper to the printing unit, and a printing unit A paper discharge unit that discharges the printing paper printed in step 1 and a plate discharge unit that removes the stencil sheet mounted on the drum. In order to reliably peel off the printing paper conveyed along with the rotation of the drum and passed through the image transfer position, a means using an instantaneous strong wind for separation has been proposed.

  This means will be briefly described with reference to FIG. 12. The stencil sheet 71 is mounted on the outer peripheral surface 70a of the drum 70, and rotates in the direction of arrow A by the driving force of a drum motor (not shown). A separation claw 72 is disposed downstream of the image transfer position of the drum 70 and in the vicinity of the outer peripheral surface 70 a of the drum 70, and a blowing nozzle 73 is provided at the tip of the separation claw 72. This blower nozzle 73 is connected to a separation pump (not shown) via a blower pipe 74, and this separation pump generates an instantaneous strong wind in synchronization with the rotation of the drum 70 using a drum motor as a drive source.

  In the above configuration, the printing paper 75 is conveyed while applying a printing pressure to the outer peripheral surface 70a of the rotating drum 70, and image transfer from the stencil sheet 71 is performed on the printing paper 75 in this conveyance process.

  When the conveyance leading edge of the printing paper 75 comes downstream from the image transfer position, the separation strong wind a is instantaneously blown from the leading edge of the separation claw 72 between the conveyance leading edge of the printing paper 75 and the outer peripheral surface 70 a of the drum 70. As shown by the phantom line in FIG. 12, the leading edge of the printing paper 75 is separated from the drum 70 by the strong wind a for separation, and the separation claw 72 is provided between the leading edge of the printing paper 75 away from the drum 70 and the drum 70. As a result, the printing paper 75 is sequentially peeled off from the drum 70. The printing paper 75 peeled off from the drum 70 is conveyed to a predetermined paper discharge path.

  That is, since the printing paper 75 immediately after printing adheres to the drum 70 side due to the viscosity of the ink, a strong separation strong wind a is blown between the conveyance leading edge of the printing paper 75 and the outer peripheral surface 70a of the drum 70 to forcibly. In addition, the printing paper 75 is separated from the drum 70 by separating the leading edge side of the printing paper 75 from the drum 70 and guiding the conveyance leading edge of the printing paper 75 separated from the drum 70 by the separation claw 72. .

  However, in the stencil printing apparatus provided with the separation pump, since the drive source is shared by using the drum motor of the drum 70 as the drive source of the separation pump, a large load is applied to the drum motor during printing. There has been a problem that the drum motor is increased in size and power consumption is increased.

  Therefore, the present invention has been made to solve the above-described problem, and is equipped with a separation pump, and can reduce the size of the drum motor and reduce the power consumption. An object is to provide a printing apparatus.

  According to the first aspect of the present invention, the drum having the stencil sheet mounted on the outer peripheral surface is rotated, the printing paper is fed to the outer peripheral surface of the rotating drum, and the printing pressure is applied to the fed printing paper. When the leading end of the printing paper comes downstream of the image transfer position, the leading edge of the printing paper and the outer peripheral surface of the drum are transferred. In a stencil printing apparatus in which a separation strong wind is instantaneously blown in between, and a drive source of a separation pump that generates the separation strong wind is a drum motor that is a drive source of the drum, the stencil printing apparatus according to the printing state of the printing paper The separation pump is controlled to be turned on / off, and when the separation pump is turned on, the drum is rotated at an economy speed lower than the maximum speed or lower than the maximum speed. To.

  In this stencil printing device, if there is not much ink attached to the printing paper conveyance front end, the printing paper conveyance leading edge can be reliably peeled off from the drum without blowing strong air for separation. Focusing on the fact that when a predetermined amount or more of ink is attached to the leading end side, the separation leading wind cannot be reliably peeled off from the drum unless the separating strong wind is blown, and the separating strong wind is necessary. When the separation pump is turned off, the load of the separation pump is not applied to the drum motor, and when the separation pump is turned on, the load of the separation pump is Although it is applied to the motor, since the drum rotation speed is lower than the economy speed, the load of the drum motor can be suppressed to a small load.

  The invention of claim 2 is the stencil printing apparatus according to claim 1, wherein the determination of the printing state of the printing paper is performed by: a printing rate at a conveyance leading end side of the printing paper and a printing position of the printing paper in a vertical direction. Is a decision factor.

  In this stencil printing apparatus, in addition to the operation of the first aspect of the present invention, it is determined whether or not the separation pump is driven according to the substantial printing state on the conveyance paper feeding front end side.

  A third aspect of the invention is the stencil printing apparatus according to the first or second aspect, wherein the printing state of the printing paper is constantly monitored during a printing operation, and the driving state of the separation pump is switched even during the printing operation. It is characterized by that.

  In this stencil printing apparatus, in addition to the action of the invention of claim 1 or claim 2, when the printing state of the printing paper is varied during the printing operation and the separation pump is switched from OFF to ON, the printing paper is surely loaded. It is peeled off from the drum. Further, when the separation pump is switched from on to off, the power consumption of the drum motor is reduced.

  According to a fourth aspect of the present invention, in the stencil printing apparatus according to the third aspect, when the separation pump is switched from OFF to ON during the printing operation, the rotation is forced when the rotation speed of the drum is higher than the economy speed. It is characterized by the fact that printing is performed at an economic speed.

  In this stencil printing apparatus, in addition to the operation of the invention of claim 3, it is possible to prevent an excessive load from being applied to the drum motor even when the printing state of the printing paper is changed during the printing operation.

  The invention of claim 5 is the stencil printing apparatus according to claim 1, wherein the drive control of the separation pump includes power transmission on / off means for turning on / off power transmission from the drum motor to the separation pump. It is characterized by being performed by controlling.

  In this stencil printing apparatus, in addition to the operation of the invention of claim 1, it is not necessary to change the design of the separation pump at all, and the conventional separation pump is used as it is. Further, the mechanical change can be dealt with by a partial design change of the power transmission system.

  A sixth aspect of the present invention is the stencil printing apparatus according to the first aspect, wherein the drum is provided with a non-volatile memory for storing information relating to a printing rate on the conveying front end side of the stencil sheet mounted on the outer peripheral surface, and the printing paper The determination of the printing state is characterized in that information relating to the printing rate stored in the non-volatile memory and the printing position in the vertical direction of the printing paper are used as determination elements.

  In this stencil printing apparatus, in addition to the operation of the invention of claim 1, even when another drum is mounted, the separation pump can be reliably controlled based on information relating to the printing rate of the drum.

  A seventh aspect of the present invention is the stencil printing apparatus according to the sixth aspect of the present invention, wherein a control condition of the separation pump is set so that when the sheet pumping-up jam occurs when the separation pump is in an off state, the separation pump is likely to be turned on. It is characterized by changing.

  In this stencil printing apparatus, in addition to the effect of the invention of claim 6, even when the separation pump is in the off state, the occurrence of the paper rising jam can be suppressed.

  The invention of claim 8 is the stencil printing apparatus according to claim 7, wherein the nonvolatile memory stores the control conditions of the separation pump.

  In this stencil printing apparatus, in addition to the effect of the invention of claim 7, even when the power is turned on next time or when another drum is mounted, the occurrence of paper rising jam can be suppressed.

  A ninth aspect of the present invention is the stencil printing apparatus according to the eighth aspect of the present invention, wherein when a paper jump jam occurs when the separation pump is in an off state, the separation pump is controlled to be in an on state.

  In this stencil printing apparatus, in addition to the effect of the invention of claim 8, the occurrence of paper rising jam can be more reliably suppressed.

  As described above, according to the first aspect of the present invention, the on / off of the separation pump is controlled according to the printing state of the printing paper, and the rotation speed of the drum is slower than the maximum speed when the separation pump is turned on. Since printing is done at an economy speed or lower, if there is not much ink adhering to the front end of the print paper, the front end of the print paper can be reliably peeled off from the drum without blowing strong wind for separation. If there is more than a predetermined amount of ink on the printing paper transport tip side, pay attention to the fact that the printing paper transport tip cannot be reliably peeled off from the drum without blowing strong air for separation. Judgment is made according to the printing state of the printing paper, and when the separation pump is turned off, the load of the separation pump is applied to the drum motor. , When to turn on the isolation pump is a load of the separation pump according to the drum motor, the rotation speed of the drum is reduced to less economy speed, it is possible to suppress the load on the drum motor to a small load. As a result, the drum motor can be miniaturized and the power consumption can be reduced.

  According to the invention of claim 2, since it is determined whether or not the separation pump is driven according to a substantial printing state on the conveyance leading end side of the printing paper, an accurate determination is possible.

  According to the invention of claim 3, since the printing state of the printing paper is constantly monitored during the printing operation, and the driving state of the separation pump is switched during the printing operation, when the separation pump is switched from OFF to ON, The printing paper can be reliably peeled off from the drum. Further, when the separation pump is switched from on to off, the power consumption of the drum motor can be reduced.

  According to the invention of claim 4, when the separation pump is switched from OFF to ON during the printing operation, the printing is forcibly reduced to the economy speed when the rotation speed of the drum is higher than the economy speed. Therefore, it is possible to prevent an excessive load from acting on the drum motor even when the printing state of the printing paper is changed during the printing operation.

  According to the invention of claim 5, the drive control of the separation pump is performed by controlling the power transmission on / off means for turning on / off the power transmission from the drum motor to the separation pump. There is no need to change the design at all, and the conventional separation pump can be used as it is. Further, the mechanical change can be dealt with by a partial design change of the power transmission system.

  According to the sixth aspect of the present invention, the drum is provided with a non-volatile memory for storing information relating to the printing rate on the conveyance front side of the stencil sheet mounted on the outer peripheral surface, and the determination of the printing state of the printing paper is performed in the non-volatile memory. Since the process is performed based on the stored information, the separation pump can be controlled without any problem even when the drum is moved to another stencil printing apparatus.

  According to the seventh aspect of the present invention, when the sheet pumping jam occurs when the separation pump is in the off state, the control condition of the separation pump is changed so that the separation pump is likely to be in the on state. Even during this time, it is possible to suppress the occurrence of a paper jump jam.

  According to the invention of claim 8, since the non-volatile memory stores the control conditions of the separation pump, even when the drum is moved to the next stencil printing apparatus at the next power-on, Occurrence can be suppressed.

  According to the ninth aspect of the present invention, when the paper rising jam occurs when the separation pump is in the OFF state, the separation pump is controlled to be in the ON state, so that the occurrence of the paper rising jam can be more reliably suppressed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 to 6 show an embodiment of the present invention, FIG. 1 is a configuration diagram of a main part of a stencil printing apparatus, and FIG. 2A is a plan view showing a power transmission means from a drum motor to a separation pump. 2 (b) is a front view showing power transmission means from the drum motor to the separation pump, FIG. 3 is a front view of the operation panel, FIG. 4 is a circuit block diagram of the main part of the stencil printing apparatus, and FIG. 5 is an operation of the separation pump. FIG. 6 is a flowchart for determining the operating conditions of the separation pump.

  As shown in FIG. 1, a stencil printing apparatus 1 includes a scanner unit (not shown) that reads image data of a document to be printed, and a plate making unit (not shown) that punches a stencil sheet 10 based on the image data read by the scanner unit. A printing unit 2 for mounting the stencil sheet 10 perforated by the plate making unit to a drum 11, conveying the printing paper 12 while applying a printing pressure to the rotating drum 11, and transferring an image to the printing paper 12; The paper feed unit 3 that feeds the printing paper 12 to the printing unit 2, the paper ejection unit 4 that delivers the printing paper 12 printed by the printing unit 2, and the stencil paper 10 mounted on the drum 11 are removed. Not equipped with a plate removal part.

  The printing unit 2 includes a drum 11 having an outer peripheral portion made of an ink-permeable member having a porous structure, and at least the outer peripheral portion of the drum 11 is rotated in the direction of arrow A in FIG. It has come to be. A stencil sheet 10 is wound around and mounted on the outer peripheral surface of the drum 11 with a base paper clamp 14 projecting from the front end. Inside the drum 11, a squeegee roll 15, a doctor roll 16 at a position near the squeegee roll 15, and an ink supply unit 17 are disposed above the squeegee roll 15, and the ink supply unit 17 is surrounded by the squeegee roll 15 and the doctor roll 16. The ink 18 is dropped into the outer peripheral space, and the dropped ink 18 is stored here. As the ink 18 adhering to the outer periphery of the rotating squeegee roll 15 passes through the gap with the doctor roll 16, only the ink 18 having a predetermined film thickness is attached to the squeegee roll 15. It is supplied to the inner peripheral surface.

  Further, a press roll 19 is provided at a position facing the squeegee roll 15 and outside the drum 11, and the press roll 19 is pressed against the outer peripheral surface of the drum 11 by a driving force of a solenoid device (not shown). , And a standby position that is separated from the outer peripheral surface of the drum 11. The press roll 19 is shifted from the standby position to the pressing position in synchronization with the paper feeding operation from the pair of paper feeding rolls 20, 20, and is positioned at the pressing position only when the printing paper 12 passes the lower part of the drum 11, At other times, it is positioned at the standby position.

  The paper feed unit 3 includes a pair of paper feed rolls 20 and 20 on the most downstream side of a conveyance path from a paper feed table (not shown). The pair of paper feed rolls 20, 20 are configured to feed the printing paper 12 between the drum 11 and the press roll 19 in synchronization with the rotational position of the drum 11.

  The paper discharge unit 4 includes a separation claw 21 that separates the printed printing paper 12 from the drum 11, a blow nozzle 22 that is disposed at the front end of the separation claw 21 and instantaneously blows strong wind for separation, and the drum 11. It has a conveyance belt 23 on which the separated printing paper 12 is conveyed, and a paper discharge tray (not shown) on which the printing paper 12 discharged from the conveyance belt 23 is placed. The blower nozzle 22 is connected to a separation pump 25 through a blower pipe 24, and the power of the drum motor 13 is transmitted to the separation pump 25 through a power transmission means 26. That is, the separation pump 25 instantaneously generates a strong wind for separation in synchronization with the rotation of the drum 11 using the drum motor 13 as a drive source.

  Next, the power transmission means 26 between the drum motor 13 and the separation pump 25 will be described. 2A and 2B, the power transmission means 26 includes a first gear pulley 30 fixed to the rotating shaft 13a of the drum motor 13, and a belt 31 having one end hung on the first gear pulley 30. A second gear pulley 32 on which the other end side of the belt 31 is hung, a drive shaft 33 to which the second gear pulley 32 is fixed, and power transmission on / off means connected to the drive shaft 33 at one end side. An electromagnetic clutch 34, a disc cam 35 fixed to the other end of the electromagnetic clutch 34, and a crank 36 having one end connected to the eccentric position of the disc cam 35 and the other end connected to the separation pump 25. It is configured.

  When the electromagnetic clutch 34 is on, the rotational force of the drum motor 13 is transmitted to the separation pump 25 via the electromagnetic clutch 34, and the separation pump 25 is turned on. When the separation pump 25 is turned on, air in an internal cylinder (not shown) is intermittently compressed using a piston by reciprocating movement of the crank 36, and the compressed air is output to the blow nozzle 22 at a predetermined timing synchronized with the rotation of the drum 11. It is like that. When the electromagnetic clutch 34 is off, the rotational force of the drum motor 13 is not transmitted to the separation pump 25 and the separation pump 25 is turned off, so that compressed air is not output to the blower nozzle 22.

  As shown in FIG. 3, the stencil printing apparatus 1 is provided with an operation panel 40. The operation panel 40 includes a plate making / printing selection key 41, a start key 42, a stop key 43, a test printing key 44, a numeric keypad 45, and the like. In addition to various keys, a print position adjustment key 46, a print density adjustment key 47, and a print speed adjustment key 48 are provided.

  The print position adjustment key 46 can be changed in the vertical (up and down) direction at intervals of 0.5 mm around the center position, and can be adjusted within a range of 10 mm each. The print density adjustment key 47 can adjust the print density in five levels. The printing speed adjustment key 48 has a total of five printing speeds (1st speed (60 sheets / min), 2nd speed (80 sheets / min), 3rd speed (100 sheets / min), 4 The speed (120 sheets / minute) and the fifth speed (130 sheets / minute) are set, and the third speed can be adjusted to the economy speed in this embodiment. The current setting state of the printing position, printing density, and printing speed is displayed with an indicator. Further, the operation panel 40 is provided with a display panel 49 for displaying various data, and is configured to display the above setting state in an overlapping manner.

  Next, the control system of the stencil printing apparatus 1 will be described.

  In FIG. 4, the input data of the operation panel 40 is output to the control unit 50, which controls the scanner unit, plate making unit, printing unit 2, paper feed unit 3, and paper discharge unit 4 based on these input data. And the plate removal unit, and the display of the display panel 49 of the operation panel 40, the display of the indicator, and the like are controlled. Further, the control unit 50 controls both the motor drive unit 51 that drives the drum motor 13 and the electromagnetic clutch drive unit 52 that turns the electromagnetic clutch 34 on and off. Further, the control unit 50 can control the plate making information reading unit 53 and acquire the printing rate data of the printing paper 12.

  Further, the control unit 50 writes and reads the ROM 54 and the RAM 55 in which various programs are stored, and executes, for example, the flow shown in FIGS. 5 and 6.

  Next, the operation of the above configuration will be described.

  As shown in FIG. 5, the power is turned on, and in the standby mode, the operating condition of the separation pump 25 is always checked (step S1).

  As shown in FIG. 6, the operating condition of the separation pump 25 reads plate making information (step S20), and checks the printing rate from the plate making information (step S21). If the printing rate within a range of 10 mm from the leading end of the printing paper 12 is 50% or more (step S22), it is determined whether or not the setting of the printing position of the printing paper 12 has been moved from the center position by 5 mm or more in the ground direction. Check (step S24), if there is no movement of 5 mm or more, it is determined that the separation pump 25 is on (step S25), and if there is a movement of 5 mm or more, it is determined that the separation pump 25 is off (step S26).

  If the printing rate within the range of 10 mm from the leading end of the printing paper 12 is less than 50% (step S22), whether there is printing within the range of 5 mm from the leading end of the printing paper 12 (the printing rate is zero). It is checked whether or not (step S23).

  If there is printing within a range of 5 mm from the conveyance leading edge of the printing paper 12, it is checked whether or not the setting of the printing position of the printing paper 12 has been moved by 5 mm or more from the center position in the ground direction (step S24). If there is no movement of 5 mm or more, it is determined that the separation pump 25 is on (step S25), and if there is a movement of 5 mm or more, it is determined that the separation pump 25 is off (step S26). If there is no printing within a range within 5 mm from the conveyance leading edge of the printing paper 12, the separation pump 25 is determined to be off without checking the printing position (step S26). The operating condition of the separation pump 25 is determined as described above.

  As shown in FIG. 5, when it is determined that the separation pump 25 is off, the indicator (speed setting) of the printing speed adjustment key 48 is not lowered (step S2), that is, the printing speed adjustment key 48 is set. Wait for selection to start printing without forcibly changing. When it is determined that the separation pump 25 is on, if the speed setting of the printing speed key 48 is 4th speed or more, the indicator (setting speed) of the printing speed adjustment key 48 is forcibly changed to the economy speed 3rd speed. (Step S3), waiting for selection to start printing. After it is determined that the separation pump 25 is turned on, even if the user tries to change the print speed to the fourth speed or the fifth speed by the print speed adjustment key 48, the input data is rejected.

  When printing start is selected (step S4), the process proceeds to a printing operation. When the operation of the separation pump 25 is determined to be on, the printing operation is performed when the electromagnetic clutch 34 is turned on and the separation pump 25 is driven, and the printing speed is between the first speed and the third speed. When it is determined that the separation pump 25 is turned off during standby, the electromagnetic clutch 34 is turned off and the separation pump 25 is not driven, and the printing speed is between 1st and 5th.

  Even during this printing operation, the operating conditions of the separation pump 25 are always checked (step S5). The operating conditions of the separation pump 25 are the same as those shown in FIG. 6 described above. When it is determined that the separation pump 25 is off (step S6), the current printing speed is maintained and the forced printing speed is set. Do not change. Then, the change of the set speed by the user's print speed adjustment key 48 is allowed in the entire range from the first speed to the fifth speed (step S7). If it is determined that the separation pump 25 is turned on during standby and the separation pump 25 is turned off during the printing operation, the drive of the separation pump 25 is stopped at that time.

  When it is determined that the separation pump 25 is on during the printing operation (step S8), it is checked whether or not the speed setting of the printing speed adjustment key 48 is 4th speed or more (step S9). If it is less than the fourth speed, the forcible printing speed is not changed as described later (step S10). Thereafter, the change of the set speed by the user's print speed adjustment key 48 is allowed only in the range of the first speed to the third speed (step S11).

  If the speed is 4 or more, the indicator (setting speed) of the print speed adjustment key 48 is forcibly changed to 3 speed (step S12), and the display panel 49 reads “Slow print speed due to overload.” Is displayed (step S13), and the printing speed is forcibly changed to the third speed for printing (step S14). Thereafter, the change of the set speed by the user's print speed adjustment key 48 is allowed only in the range from the first speed to the third speed (step S16). Any attempt to change the setting to 4th speed or 5th speed will be rejected. Further, when it is determined that the separation pump 25 is off during standby and the separation pump 25 is turned on during the printing operation, the driving of the separation pump 25 is started from that point.

  As described above, in the stencil printing apparatus 1, when the ink 18 is not attached to the leading end side of the printing paper 12, the leading end of the printing paper 12 can be reliably peeled off from the drum 11 without blowing strong air for separation. In the case where a predetermined amount or more of ink 18 is adhered to the leading end side of the printing paper 12, the leading end of the printing paper 12 cannot be reliably peeled off from the drum 11 without blowing strong air for separation. Is focused on.

  Then, it is determined whether or not a strong wind for separation is necessary according to the printing state of the printing paper 12, and when the separation pump 25 is turned off, the load of the separation pump 25 is not applied to the drum motor 13 and the separation pump 25 is separated. When the pump 25 is turned on, the load of the separation pump 25 is applied to the drum motor 13, but the drum 11 is rotated only at the third speed (economy speed) or less, so that the load is suppressed to a small load. As described above, with the separation pump 25 mounted, the drum motor 13 can be reduced in size and power consumption can be reduced.

  In the above-described embodiment, the determination of the printing state of the printing paper 12 is based on the printing rate at the leading end side of the printing paper 12 and the printing position of the printing paper 12 in the vertical direction. Since it is determined whether or not the separation pump 25 is driven according to a substantial printing state in FIG.

  According to the above embodiment, the printing state is determined with reference to 10 mm from the conveyance leading end of the printing paper 12, and the movement amount of the printing paper 12 is determined with reference to 5 mm from the center position toward the ground. These condition settings are appropriately determined in consideration of various conditions.

  In the above-described embodiment, the printing state of the printing paper 12 is constantly monitored even during the printing operation, and the driving state of the separation pump 25 is switched during the printing operation. Therefore, when the separation pump 25 is switched from off to on, it is ensured. In addition, the printing paper 12 can be peeled off from the drum 11. Further, when the separation pump 25 is switched from on to off, the power consumption of the drum motor 13 can be reduced.

  In the above-described embodiment, when the separation pump 25 is switched from OFF to ON during the printing operation, if the rotation speed of the drum 11 is higher than the third speed (economy speed), the printing is forcibly reduced to the economy speed for printing. Therefore, it is possible to prevent an excessive load from acting on the drum motor 13 even when the printing state such as the printing position of the printing paper 12 is changed during the printing operation. Specifically, it is determined that the separation pump 25 is off during standby, and if the print speed setting at that time is 4 or more, it is determined that the separation pump 25 is on during a printing operation due to a change in the subsequent printing state. In this case, the drum motor 13 is not overloaded.

  In the above-described embodiment, the third speed (100 sheets / minute) is the economy speed. However, the economy speed is appropriately determined in consideration of the performance of the drum motor 13 and the load state at each speed.

  In the above embodiment, the drive control of the separation pump 25 is performed by controlling the electromagnetic clutch (power transmission on / off means) 34 for turning on / off the power transmission from the drum motor 13 to the separation pump 25. It is not necessary to change the design of 25 at all, and the conventional separation pump 25 can be used as it is. The mechanical change can be dealt with by a partial design change of the power transmission means system.

  Here, as another embodiment, as shown in FIG. 7, the control unit 50 controls the plate making information reading unit 53 to acquire the plate making information from the nonvolatile memory 56 built in the drum 11. Good. By configuring the control unit 50 to acquire the plate making information from the nonvolatile memory 56, the separation pump 25 can be controlled even when another drum 11 is mounted.

In this case, information regarding the printing rate on the leading end side of the stencil sheet 10 (print rate information) may be included in the plate making information. The printing rate is calculated from the plate-making image at the time of making the stencil sheet 10 and, as shown in FIG. 8, the printing rate at 0.5 mm width from the tip (0.0 mm) of the stencil sheet 10 to 20 mm is set to 0 to 0. It is desirable to divide and store the stencil sheet 10 in the sub-scanning direction by describing it with an integer in the range of 100. Here, in FIG. 8, N represents a threshold value of the printing rate indicating the driving condition of the separation pump 25. In this embodiment, the initial value of the threshold value N is set to 50, and according to the occurrence of a paper rising jam described later. It varies within the range of 0-50. C [1], c [2],..., C [40] are 0.0 mm to 0.5 mm, 0.5 mm to 1.0 mm,. It represents the average printing rate at a width position of 20.0 mm. In this way, by dividing the printing rate at the leading end of the stencil sheet 10 in the sub-scanning direction and storing it, when changing the setting of the printing position of the printing paper 12, printing is performed at a lower cost than recalculating from the plate-making image. The rate can be calculated. Further, since it is not necessary to store a large-capacity image image in the nonvolatile memory 56, the capacity of the nonvolatile memory 56 can be reduced.

  In this case, the operating condition of the separation pump 25 may be determined according to the flowchart shown in FIG. That is, as shown in the flowchart of FIG. 9, plate making information is read from the nonvolatile memory 56 (step S30), and the printing rate is checked from the read plate making information (step S31). If the printing rate within 10 mm from the conveyance leading edge of the printing paper 12 is equal to or greater than the threshold value N% (step S32), it is determined that the separation pump 25 is on (step S33). If the printing rate in the range within 10 mm is less than the threshold value N% (step S32), it is determined whether or not there is printing in the range within 5 mm from the conveyance leading edge of the printing paper 12 (printing rate is zero). Check (step S34). Then, if there is printing within a range within 5 mm from the conveyance leading edge of the printing paper 12, it is determined that the separation pump 25 is turned on (step S33), and if there is no printing within a range within 5 mm from the conveyance leading edge of the printing paper 12, separation is performed. It is determined that the pump 25 is turned off (step S35). The printing rate within a range of 10 mm from the conveyance leading edge of the printing paper 12 is an average value of the printing ratios c [1] to c [20] (see FIG. 8) for each 0.5 mm width from the conveyance leading edge to 10 mm. Calculated. Further, when the setting of the printing position of the printing paper 12 is changed, the printing rate is recalculated as shown in FIG. That is, as shown in FIG. 10A, the printing top position is 5 mm on the ground side compared to the standard position shown in FIG. 10B (the front end position of the stencil sheet 10 and the front end position of the printing paper 12 are the same). When moved, the printing rate within 10mm from the transport tip is all the printing rate within the range of 5mm on the ground side (0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5). Assuming 0, it is recalculated to (0 × 10 + c [1] +... + C [10]) / 20. Further, as shown in FIG. 10C, when the printing top position is moved 5 mm toward the top as compared with the standard position shown in FIG. 10B, the printing rate within the range of 10 mm from the conveyance tip is , (C [11] +... + C [30]) / 20.

  Furthermore, when an error (denoted as paper rising jam) occurs in which the conveyance leading edge of the printing paper 12 does not peel off from the drum 11 when the separation pump 25 is in the off state, the printing rate is changed according to the flowchart shown in FIG. It is desirable that the threshold value N is changed to a value at which the separation pump 25 is likely to be turned on, so that the printing condition is controlled so that the paper jump-up jam hardly occurs. That is, as shown in the flowchart of FIG. 11, the occurrence of a paper jump jam is monitored (step S40), and a warning message such as “please remove the paper jump” is operated in response to the paper jump jam. It displays on the panel 40 (step S41). Then, as the printing paper 12 is removed (step S42), it is determined whether or not the separation pump 25 is in an off state (step S43). If the separation pump 25 is in an on state, the separation pump The printing process is started while 25 is on (step S44). On the other hand, when the separation pump 25 is in an off state, a question message such as “Do you want to operate the separation pump (the power consumption may increase or the printing speed may decrease)” is displayed on the operation panel 40. Displayed (step S45). Then, it is determined whether or not the on button for instructing the start of printing is selected in response to the question message (step S46). If the on button is not selected, the printing process is started while the separation pump 25 is in the off state. At the same time, the printing rate threshold value N is set to a value obtained by subtracting a predetermined value (−5) (0 if N becomes negative as a result of the subtraction) (step S47), and the set threshold value N is written to the nonvolatile memory 56. Return (step S48). On the other hand, when the ON button is selected, the separation pump is turned on to start the printing process, and the printing rate threshold value N is set to 0 (step S49), and the set threshold value N is set to the nonvolatile memory 56. (Step S48). By controlling the printing conditions in such a way that the paper rising jam is unlikely to occur, even if the printing paper 12 contains moisture and the paper rising jam is likely to occur, the separation pump is based on the printing rate. By controlling to turn off 25, it is possible to prevent a paper jump jam. Further, when the separation pump 25 is changed to a value at which the separation pump 25 is likely to be turned on, the threshold value N is written back to the nonvolatile memory 6 so that the drum 11 is moved to the next stencil printing apparatus when the power is turned on next time. Even so, it is possible to prevent the paper jam from occurring.

1 is a configuration diagram of a main part of a stencil printing apparatus according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a plan view showing power transmission means from a drum motor to a separation pump, and FIG. 5B is a front view showing power transmission means from the drum motor to the separation pump. FIG. 3 is a front view of an operation panel according to an embodiment of the present invention. 1 is a circuit block diagram of a main part of a stencil printing apparatus according to an embodiment of the present invention. It is a flowchart regarding the operation | movement of a separation pump and the rotational speed of a drum, showing one Example of this invention. It is a flowchart which shows one Example of this invention and judges the operating condition of a separation pump. FIG. 5 is a circuit block diagram of a main part of a stencil printing apparatus according to another embodiment of the present invention. It is a schematic diagram which shows the other Example of this invention and shows the data structure of printing rate information. It is a flowchart which shows the other Example of this invention and judges the operating condition of a separation pump. FIG. 10 is a schematic diagram for explaining a recalculation method of a printing rate according to another embodiment of the present invention. It is a flowchart which shows the other Example of this invention and changes the operating condition of a separation pump. It is sectional drawing which shows a prior art example and shows the state from which the printing paper adhere | attached on the drum is peeled off with the strong wind of a separation pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Stencil printing apparatus 10 ... Stencil paper 11 ... Drum 12 ... Printing paper 13 ... Drum motor 25 ... Separation pump 34 ... Electromagnetic clutch (power transmission on / off means)

Claims (9)

The drum with the stencil paper mounted on the outer peripheral surface is rotated, the printing paper is fed to the outer peripheral surface of the rotating drum, and the printing paper is conveyed along with the rotation of the drum while applying printing pressure to the fed printing paper. When the image is transferred from the stencil sheet to the printing paper, and the conveyance leading edge of the printing paper comes downstream of the image transfer position, a strong separation wind is instantaneously generated between the conveyance leading edge of the printing paper and the outer peripheral surface of the drum. In the stencil printing apparatus, the drive source of the separation pump that generates the strong wind for separation is a drum motor that is the drive source of the drum.
The separation pump is controlled to be turned on / off according to the printing state of the printing paper, and when the separation pump is turned on, the drum is rotated at an economy speed lower than the maximum speed or lower than the maximum speed. A stencil printing apparatus characterized by the above. The stencil printing apparatus according to claim 1,
The stencil printing apparatus according to claim 1, wherein the determination of the printing state of the printing paper uses the printing rate at the leading end side of the printing paper and the printing position of the printing paper in the vertical direction. The stencil printing apparatus according to claim 1 or 2,
A stencil printing apparatus, wherein the printing state of the printing paper is constantly monitored during a printing operation, and the driving state of the separation pump is switched even during the printing operation. The stencil printing apparatus according to claim 3, wherein
When the separation pump is switched from OFF to ON during the printing operation, the stencil printing apparatus forcibly reduces the economy speed to the economy speed when the rotation speed of the drum is higher than the economy speed. The stencil printing apparatus according to claim 1,
The stencil printing apparatus, wherein the drive control of the separation pump is performed by controlling power transmission on / off means for turning on / off power transmission from the drum motor to the separation pump. The stencil printing apparatus according to claim 1,
The drum includes a non-volatile memory that stores information relating to a printing rate on the conveyance front end side of the stencil sheet mounted on the outer peripheral surface,
The stencil printing apparatus according to claim 1, wherein the determination of the printing state of the printing paper uses information relating to a printing rate stored in the nonvolatile memory and a printing position in a vertical direction of the printing paper as determination elements. The stencil printing apparatus according to claim 6,
A stencil printing apparatus, characterized in that, when a paper jam occurs when the separation pump is in an off state, a control condition of the separation pump is changed so that the separation pump is easily turned on. The stencil printing apparatus according to claim 7,
The stencil printing apparatus, wherein the nonvolatile memory stores a control condition of the separation pump. The stencil printing apparatus according to claim 1,
The stencil printing apparatus according to claim 1, wherein when a paper jam occurs when the separation pump is in an off state, the separation pump is controlled to be in an on state.

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