JP3547713B2 - Stencil printing apparatus and stencil conveying method of the apparatus - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a stencil printing machine for performing a stencil printing on a stencil sheet by thermally stenciling a desired image on a stencil sheet and transferring ink from a perforated portion of the stencil sheet to a printing sheet. In particular, the present invention relates to a stencil printing apparatus suitable for performing stencil printing of a desired image in multiple colors, and a stencil conveyance control method of the apparatus.
[0002]
[Prior art]
Stencil printing in which a stencil sheet on which a desired image has been thermally perforated is mounted on a cylindrical drum, and ink supplied from the inside of the drum is passed through the perforated portion of the stencil sheet and transferred to printing paper to perform desired printing. The device is already known.
[0003]
In this type of stencil printing apparatus, a stencil sheet wound in a roll is transported between a thermal head as a stencil making unit and a platen roller. The stencil sheet is transported by a platen motor that drives a platen roller. Then, the plate is perforated by a thermal head using a thermal head. The stencil sheet thus formed is conveyed toward the drum by a stencil sheet feeding unit such as a conveying roller. Then, the plate is wound around the peripheral wall of the drum and is subjected to plate making. When the perforated stencil sheet is applied to the peripheral wall of the drum, ink is supplied from the inside of the drum to the peripheral wall surface as the drum rotates. Then, ink is extruded from the perforated portion of the stencil sheet that has been made.
[0004]
In synchronization with the above operation, when the printing paper fed from the paper feed table passes between the peripheral wall of the drum and the press roller to which a certain pressure is applied, the ink passes through the perforated portion of the stencil sheet that has been made. And transferred to printing paper. As a result, printing is performed on the printing paper with the desired image, and the printed paper is discharged to the paper discharge tray.
[0005]
By the way, in the stencil printing apparatus, when the stencil sheet is transported to the drum, the stencil driving speed of the stencil section and the transport speed of the stencil sheet feeding section are provided with a technique for making a difference in speed in order to prevent stencil movement of the stencil sheet. Has adopted.
[0006]
[Problems to be solved by the invention]
Generally, in a stencil printing apparatus, the transport speed of the stencil sheet feeding section is set to be faster than the stencil driving speed of the stencil section. Therefore, the stencil sheet feeding section performs the stencil making operation in the stencil making section while applying an appropriate tension to the stencil sheet. The actual stencil making speed of the stencil sheet in the stencil making section at this time is almost the same as the stencil making speed set by the platen motor drive circuit.
[0007]
However, when the transport distance of the stencil sheet from the stencil unit to the drum is long, the tension of the stencil sheet increases. Then, the actual plate making speed of the stencil sheet approaches the transport speed of the stencil sheet feeding section. As a result, the stencil sheet is dragged during plate making, and image elongation occurs.
[0008]
Further, when a plurality of drums are provided and the transport distances of the stencil paper are different from each other, the stencil making speed varies depending on the transport distances, which causes image expansion and contraction. If multi-color and multi-plate printing is performed using a plurality of drums and different degrees of image expansion and contraction occur in each of the plates, it becomes impossible to print all the plates without displacement.
[0009]
The present invention has been made in view of the above problems, and has as its object to optimize a stencil driving speed during stencil making by detecting a passing point of a stencil sheet with a sensor. It is another object of the present invention to reduce the expansion and contraction of the image of the stencil sheet and perform stencil printing with good reproducibility.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a stencil printing apparatus according to a first aspect of the present invention includes:
A stencil making unit 4 comprising a thermal head 31 and a platen roller 32 provided at a position facing the thermal head 31. The stencil making unit 4 perforates a desired image while transporting the stencil sheet 2 by rotating the platen roller 32. When,
A plurality of cylindrical drums 5A and 5B on which the stencil sheet 2 made by the plate making section 4 can be wound;
When the stencil sheet 2 is conveyed and wound to any one of the drums, the stencil sheet 2 is communicated with the common conveyance path 49 commonly used by all the drums 5A and 5B, and communicates with the common conveyance path 49. A transport path composed of a non-common transport path 56;
A transport section for transporting the stencil sheet 2 made at a predetermined speed on the transport path, detection means 44, 48, 52, and 55 for detecting passage of the stencil sheet 2 at a predetermined position on the transport path;
When it is determined from the detection signals of the detecting means 44, 48, 52, and 55 that the stencil sheet 2 has been transported at the boundary between the common transport path 49 and the non-common transport path 56, the platen roller 32 in the plate making section 4 is determined. Control means 61 for controlling the driving speed of theIt is characterized by having.
[0012]
The present invention2The stencil printing apparatus of the aspect1In the stencil printing machine according to the aspect, the common transport path 49 may include:
An upstream-side fixed guide plate 41 whose one end communicates with the stencil making section 4 and is opposed to the stencil sheet 2 at an interval allowing passage of the stencil sheet 2;
The interval at which the stencil sheet 2 can pass is set such that one end side communicates with the other end side of the upstream fixed guide plate 41 and the other end side communicates with the non-common transport path 56 or the clamp mechanism 7 of the drum 5B. An upstream movable guide plate 46 disposed opposite to
Consisting of
The non-common transport path 56 includes
A downstream fixed guide plate 50 whose one end communicates with the common transport path 49 and is opposed to the stencil sheet 2 at an interval allowing the stencil sheet 2 to pass through;
One end is communicated with the downstream fixed guide plate 53, and the other end is opposed to the stencil paper 2 so as to communicate with the clamping mechanism 7 of the drum 5 </ b> A. When,
It is characterized by comprising.
[0014]
The present invention3The stencil sheet conveying method of the stencil printing apparatus according to the aspect,
Stencil making a desired image while transporting the stencil sheet 2,
A common transport path 49 that is commonly used for all the drums 5 when the stencil sheet 2 that has been made is transported and wound to any one of the plurality of cylindrical drums 5A and 5B; A stencil sheet 2 made at a predetermined speed on a transfer path of the stencil sheet 2 comprising a non-common transfer path 56 communicating with a transfer path 49;
When the passage of the stencil sheet 2 in the common transport path 49 and the non-common transport path 56 is detected, and it is determined that the stencil sheet 2 has been transported at the boundary between the common transport path 49 and the non-common transport path 56, , Reducing the conveying speed of the stencil sheet 2,
The stencil sheet 2 is wound around a cylindrical drum 5.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram showing a schematic configuration of a stencil printing apparatus according to the present invention.
[0016]
Hereinafter, the overall configuration of the stencil printing apparatus will be described with reference to FIG. The stencil printing apparatus 1 has both a stencil making function of thermally perforating a desired image on the stencil sheet 2 and a printing function of performing stencil printing on the printing paper 3 using the stencil sheet 2 that has been made. As the stencil sheet 2 as a recording medium, a sheet in which a porous support is stuck on a heat-sensitive film is used.
[0017]
As shown in FIG. 1, the stencil printing apparatus 1 includes a single stencil making unit 4 described below and two cylindrical drums 5 (first drum 5 </ b> A, first drum 5 </ b> A) rotatably supported around their own central axis. And two drums 5B). The stencil printing apparatus 1 performs stencil printing of a desired image by one printing operation using two colors of printing ink. Here, the first drum 5A is located on the left side of the drawing, away from the plate making section 4, and the second drum 5B is located on the right side of the drawing, being close to the plate making section 4.
[0018]
The peripheral wall 6 of each of the drums 5A and 5B has a substantially cylindrical porous structure. Each peripheral wall 6 has a clamp mechanism 7 that locks one end of the stencil sheet 2 on the outer peripheral portion. The drums 5A and 5B are intermittently or continuously rotated in the counterclockwise direction in FIG. 1 by the power of a plate cylinder drive motor (not shown).
[0019]
As shown in FIG. 1, a printing ink supply unit 8 is provided inside the peripheral wall 6 of each of the drums 5A and 5B. The printing ink supply unit 8 is provided so that the outer peripheral surface thereof contacts the inner peripheral surface of the peripheral wall 6. The printing ink supply means 8 has a squeegee roller 9 rotatable around its own central axis, and a pair of doctor rollers 10a and 10b. The doctor rollers 10 a and 10 b extend along the generatrix direction of the squeegee roller 9 at a predetermined interval with respect to the outer peripheral surface of the squeegee roller 9. The printing ink supply unit 8 supplies the printing ink 12 in the ink pool 11 by rotating the squeegee roller 9 in the same direction as the drum 5A (or drum 5B) in synchronization with the rotation of the drum 5A (or drum 5B). It is supplied to the inner peripheral surface of the peripheral wall 6. The squeegee roller 9 is moved by a mechanism (not shown) so that the peripheral wall 6 bulges radially outward from the inside during printing.
[0020]
In addition, in the stencil printing apparatus 1 shown in FIG. 1, since multicolor printing using two colors is performed, different colors of ink are used for the printing ink 12 of the first drum 5A and the second drum 5B.
[0021]
The printing ink 12 in the ink reservoir 11 passes through the gap between the squeegee roller 9 and the doctor roller 10 a with the rotation of the squeegee roller 9, and forms a printing ink layer having a uniform thickness on the outer peripheral surface of the squeegee roller 9. I do. The printing ink layer is supplied to the inner peripheral surface of the peripheral wall 6 with the rotation of the squeegee roller 9 and is used for printing.
The doctor roller 10b prevents ink leakage from the gap between itself and the squeegee roller 9 when the doctor roller 10b is left on the drum 5B for a long time.
[0022]
A single backing roller 13 as a roller member is provided outside each of the drums 5A and 5B. The back pressing roller 13 has an outer peripheral surface of each of the drums 5A and 5B.WeekIt is arranged close to the outer peripheral surface of the wall 6 facing the squeegee roller 9. The backing roller 13 is formed of an inelastic material such as a metal. The back pushing roller 13 is configured to have substantially the same outer shape as the peripheral wall 6 of each of the drums 5A and 5B. The back pushing roller 13 is provided in parallel with the peripheral wall 6 of each of the drums 5A and 5B at a predetermined distance from the peripheral wall by the central axis. The backing roller 13 has a concave portion 14 for avoiding interference with a clamp mechanism (a clamp plate, a clamp base plate, or the like) on the peripheral wall 6 of each of the drums 5A and 5B. Each of the drums 5A and 5B and the backing roller 13 are configured so that their outer peripheral surfaces are pressed against each other with the movement of the squeegee roller 9 during printing.
[0023]
A paper clamp member 15 is provided on the back pressing roller 13. The paper clamp member 15 is swingably mounted on the back pushing roller 13 by a pivot (not shown). At one end of the paper clamp member 15, there is provided a clamp piece 16 that cooperates with the outer peripheral surface of the back-press roller 13 to removably clamp the print paper 3.
[0024]
Although not shown, the back pushing roller 13 is provided with a cam mechanism for clamping or releasing the printing paper 3.
[0025]
In FIG. 1, a paper feed unit 21 is provided diagonally below and to the left of the back pressing roller 13. The paper supply unit 21 has a paper supply table 22 on which the printing paper 3 is stacked. The paper feed table 22 is moved up and down by a driving device (not shown) in accordance with the loaded amount of the set printing paper 3.
[0026]
A paper feed mechanism 23 is provided near the paper feed table 22. The paper feed mechanism 23 includes a paper feed roller 24 made of rubber or the like, and a plurality of sets of transport rollers 25. The paper feed roller 24 picks up the printing paper 3 stacked on the paper feed table 22 one by one from the uppermost one and conveys it to the conveyance roller 25 side. The transport roller 25 feeds the printing paper 3 sent from the paper feed roller 24 between the peripheral wall 6 of the first drum 5A and the backing roller 13 at an appropriate timing.
[0027]
In FIG. 1, a printing paper separating claw 26 is provided below the second drum 5B and near the outer peripheral surface of the backing roller 13. The printing paper separating claw 26 is for removing the printed printing paper 3 on which printing has been completed from above the backing roller 13. The printed printing paper 3 peeled off by the printing paper separating claw 26 is conveyed to the paper discharging unit 28 side by a paper discharging device 27 including, for example, a roller pair and a belt conveyor device shown in the drawing. The paper discharge unit 28 has a paper discharge table 29 for stacking and storing the printed printing paper 3 conveyed by the paper discharge device 27.
[0028]
In FIG. 1, a stencil sheet 2 in the form of a continuous sheet wound in a roll shape is stored in a storage unit 30 at an obliquely right upper side of the paper discharge unit 28. The stencil sheet 2 is given a predetermined tension by a tension applying device (not shown) so that a braking force (brake) is applied to the core in a state where the stencil sheet 2 is set in the storage unit 30.
[0029]
In FIG. 1, the stencil making unit 4 is provided on the downstream side near the storage unit 30 that stores the stencil paper 2. The plate making section 4 has a thermal head 31 and a platen roller 32 facing the thermal head 31. The platen roller 32 conveys the stencil sheet 2 by a platen motor 66 driven through a platen motor drive circuit 67 in accordance with a command from a control unit 61 described later. The stencil making section 4 performs the stencil making of the stencil sheet 2 conveyed from the storage section 30 by the rotation of the platen roller 32 by the thermal head 31 in a thermosensitive manner.
[0030]
In the thermal head 31, heating elements that selectively generate heat in accordance with image signals of image data read by a document reading unit (not shown) or image data transferred from an external device are fixed in a horizontal row, that is, in the main scanning direction. Many are arranged at intervals. The thermal head 31 has an elongated plate shape, and is provided in contact with the upper surface of the stencil sheet 2 to be conveyed and in parallel with the width direction (main scanning direction) of the stencil sheet 2. The thermal head 31 is movable in a direction approaching or separating from the platen roller 32. That is, the thermal head 31 comes into contact with the platen roller 32 when the stencil sheet 2 is punched, and separates from the platen roller 32 when the stencil sheet 2 is not punched.
[0031]
In FIG. 1, an upstream fixed guide plate 41 is disposed downstream of the plate making section 4 as viewed from the storage section 30. The upstream fixed guide plate 41 is composed of a horizontal upper guide plate 41a and a U-shaped lower guide plate 41b which are arranged with an interval capable of conveying the stencil sheet 2. The U-shaped space portion of the lower guide plate 41b forms a storage portion 42 for loosening and storing the stencil sheet 2 when the stencil sheet 2 is applied to the second drum 5B.
[0032]
At both ends of the upstream side fixed guide plate 41, transport rollers 43A and 43B are provided. The transport rollers 43A and 43B include a driving roller 43a and a driven roller 43b for transporting the stencil sheet 2 to the drum 5 side. In FIG. 1, an upstream stencil sheet standby sensor 44 as a detecting means for detecting the passage of the stencil sheet 2 being conveyed is disposed near the upstream side of the conveying roller 43B on the left side of the upstream fixed guide plate 41. . A cutter device 45 for cutting the stencil sheet 2 having finished making a desired image is provided between the upstream side stencil sheet standby sensor 44 and the storage section 42.
[0033]
An upstream movable guide plate 46 is disposed downstream of the upstream fixed guide plate 41 so as to communicate with and connect to the upstream fixed guide plate 41. The upstream movable guide plate 46 is composed of two horizontal guide plates which are arranged at an interval capable of conveying the stencil sheet 2. The upstream movable guide plate 46 is connected to and communicates with the upstream fixed guide plate 41 by an upstream movable guide motor 70 driven through an upstream movable guide motor drive circuit 71 by a command from a control means 61 described later. The predetermined angle can be inclined toward the clamp mechanism 7 of the second drum 5B with the side to be supported as a fulcrum. At both ends of the upstream movable guide plate 46, a transport roller 47 composed of a driving roller 47a and a driven roller 47b for transporting the stencil sheet 2 is disposed. In FIG. 1, an upstream stencil sheet feed sensor 48 as a detecting means for detecting the passage of the stencil sheet 2 to be conveyed is disposed near the downstream side of the conveyance roller 47 on the left side of the upstream movable guide plate 46. .
[0034]
The upstream fixed guide plate 41 and the upstream movable guide plate 46 are commonly used by the first drum 5A and the second drum 5B for transporting the stencil sheet 2 toward the respective drums 5A and 5B. A common transport path 49 is formed.
[0035]
In FIG. 1, a downstream fixed guide plate 50 is disposed downstream of the upstream movable guide plate 46 that forms part of the common transport path 49 so as to communicate with and connect to the upstream movable guide plate 46. ing. The downstream side fixed guide plate 50 is composed of two horizontal guide plates arranged at an interval capable of conveying the stencil sheet 2.
[0036]
A transport roller 51 is provided near the downstream fixed guide plate 50. The transport roller 51 includes a driving roller 51a and a driven roller 51b for transporting the stencil sheet 2 to the first drum 5A. In FIG. 1, a downstream stencil sheet standby sensor 52 as a detecting means for detecting the passage of the stencil sheet 2 to be conveyed is arranged near the upstream side of the conveyance roller 51 on the left side of the downstream fixed guide plate 50. .
[0037]
A downstream movable guide plate 53 is disposed downstream of the downstream fixed guide plate 50 so as to communicate with and connect to the downstream fixed guide plate 50. The downstream side movable guide plate 53 is composed of two horizontal guide plates arranged at an interval capable of conveying the stencil sheet 2. The downstream movable guide plate 53 communicates with and connects to the downstream fixed guide plate 50 by a downstream movable guide motor 72 driven through a downstream movable guide motor drive circuit 73 in accordance with a command from a control unit 61 described later. With respect to the fulcrum, a predetermined angle can be inclined toward the clamp mechanism 7 of the first drum 5A. At both ends of the downstream side movable guide plate 53, a transport roller 54 composed of a driving roller 54a and a driven roller 54b for transporting the stencil sheet 2 toward the clamp mechanism 7 of the first drum 5A is provided. In FIG. 1, a downstream stencil sheet feed sensor 55 as a detecting means for detecting the passage of the stencil sheet 2 to be conveyed is disposed near the downstream side of the conveying roller 54 on the left side of the downstream movable guide plate 53. .
[0038]
The downstream fixed guide plate 50 and the downstream movable guide plate 53 form a non-common transport path 56 used only by the first drum 5A for transporting the stencil sheet 2 toward the first drum 5A. ing. Immediately before the start of stencil making on the stencil sheet 2, the common transport path 49 and the non-common transport path 56 are in a horizontal state, as indicated by the solid lines in FIG.
[0039]
In FIG. 1, a transport roller 57 composed of a pair of rollers for transporting the stencil sheet 2 is provided between the storage unit 30 and the stencil unit 4. Although not shown, the driving rollers 43a, 47a, 51a, 54a of the transport rollers 43A, 43B, 47, 51, 54 in the common transport path 49 and the non-common transport path 56, including the transport roller 57, are endless belts. It is connected to a feed motor 66 to be described later. The transport rollers 43, 47, 51, 54, 57, the endless belt, a later-described feed motor 68 and a feed motor drive circuit 69 constitute a transport drive unit.
[0040]
Here, FIG. 2 is a block diagram in which a stencil sheet 2 is subjected to stencil making, and only a configuration for plate-making the stencil sheet 2 having been made on each drum is extracted.
[0041]
2 will be described. When the upstream stencil sheet standby sensor 44 conveys the stencil sheet 2 subjected to thermal plate making to the first drum 5A or the second drum 5B, when the leading end of the stencil sheet 2 passes. In addition, a detection signal indicating that the stencil sheet 2 has passed through the upstream fixed guide plate 41 of the common transport path 49 is input to the control means 61.
[0042]
The upstream-side stencil sheet feed sensor 48 moves the stencil sheet 2 upstream of the common transport path 49 when the leading end of the stencil sheet 2 passes when the heat-sensitive stencil sheet 2 is applied on the second drum 5B. A detection signal indicating that the vehicle has passed through the guide plate 46 is input to the control means 61.
[0043]
The downstream-side stencil sheet standby sensor 52 detects that when the leading end of the stencil sheet 2 passes when the stencil sheet 2 subjected to thermal plate making is conveyed to the first drum 5A side, the stencil sheet 2 is downstream of the non-common conveyance path 56 A detection signal indicating that the light has passed through the fixed guide plate 50 is input to the control means 61.
[0044]
The downstream side stencil feed sensor 55 detects that when the leading end of the stencil sheet 2 passes through the stencil sheet 2 subjected to thermal plate making on the first drum 5A, the stencil sheet 2 moves downstream of the non-common transport path 56. A detection signal indicating that the vehicle has passed through the movable guide plate 53 is input to the control means 61.
[0045]
Here, the horizontal position where the upstream movable guide plate 46 communicates with and connects to the upstream fixed guide plate 41 and the downstream fixed guide plate 50 is defined as the upper limit position. The upstream movable guide plate upper limit sensor 62 detects whether or not the upstream movable guide plate 46 is located at the upper limit position. Then, the detection signal at that time is input to the control means 61.
[0046]
Here, the lower position is a position where the stencil sheet 2 subjected to thermal plate making is inclined by a predetermined angle to guide the stencil sheet 2 to the clamp position of the clamp mechanism 7 of the second drum 5B. The upstream movable guide plate lower limit sensor 63 detects whether or not the upstream movable guide plate 46 is located at this lower limit position. Then, the detection signal at that time is input to the control means 61.
[0047]
Here, the horizontal position where the downstream movable guide plate 53 communicates with and connects to the downstream fixed guide plate 50 is defined as the upper limit position. The downstream movable guide plate upper limit sensor 64 detects whether or not the upstream movable guide plate 53 is located at the upper limit position. Then, the detection signal at that time is input to the control means 61.
[0048]
Here, a position in which the stencil sheet 2 subjected to the thermal plate making is inclined by a predetermined angle to guide the stencil sheet 2 to the clamp position of the clamp mechanism 7 of the first drum 5A is defined as a lower limit position. The downstream movable guide plate lower limit sensor 65 detects whether or not the downstream movable guide plate 53 is located at the lower limit position. Then, the detection signal at that time is input to the control means 61.
[0049]
The platen motor 66 is composed of, for example, a stepping motor. The platen motor 66 rotationally drives the platen roller 32 that conveys the stencil sheet 2 when performing a thermal stencil making of a desired image on the stencil sheet 2.
[0050]
The platen motor drive circuit 67 drives the platen motor 66 to rotate at a predetermined plate-making drive speed according to a command from the control means 61. When the stencil sheet 2 reaches the boundary between the common transport path 49 and the non-common transport path 56, the stencil driving speed is reduced.
[0051]
The feed motor 68 is, for example, a stepping motor. The feed motor 68 rotates the respective transport rollers 43A, 43B, 47, 51, 54, 57 via an endless belt (not shown) in order to transport the stencil sheet 2 at a predetermined speed in the transport paths 49, 56. I have.
[0052]
The feed motor drive circuit 69 drives the feed motor 68 to rotate at a predetermined speed in accordance with a command from the control means 61.
[0053]
The upstream movable guide motor 70 moves the upstream movable guide plate 46 between a horizontal state (upper limit position) and an inclined state (lower limit position).
[0054]
The upstream movable guide motor drive circuit 71 drives the upstream movable guide motor 70 to rotate forward or reverse according to a command from the control means 61.
[0055]
The downstream movable guide motor 72 moves the downstream movable guide plate 53 between a horizontal state (upper limit position) and an inclined state (lower limit position).
[0056]
The downstream-side movable guide motor drive circuit 73 drives the downstream-side movable guide motor 72 to rotate forward or reverse according to a command from the control unit 61.
[0057]
The control program for controlling the operation of the flowchart shown in FIGS. 3 to 5 described later is stored in the ROM 74 as the storage means. Further, the RAM 75 as a storage means is used for storing work variables of the control means 61 and the like.
[0058]
The control means (CPU) 61 supervises a series of stencil printing operations including thermal stencil making on the stencil 2 with a desired image, stencil making of the stencil 2 thus made, and printing in two colors. The control means 61 receives signals from the stencil sheet standby sensors 44 and 52, the stencil sheet feed sensors 48 and 55, the movable guide plate upper limit sensors 62 and 64, and the movable guide plate lower limit sensors 63 and 65 according to a control program of the ROM 74. The operation of the flowcharts shown in FIGS. 3 to 5 described below is controlled.
[0059]
The control means 61 determines a predetermined time after the stencil sheet standby sensor (44 or 52) is turned on, a predetermined time since the stencil sheet feed sensor (48 or 55) is turned on, and the operation time of the platen motor 66. A timer 61a for measuring is provided.
[0060]
Next, the operation of the stencil printing apparatus 1 having the above configuration will be described with reference to FIGS. Here, a description will be given of the operation from the step of forming a desired image on the stencil sheet 2, which is a main part of the present embodiment, to the step of forming a plate on each of the drums 5A and 5B.
[0061]
3 is a main flowchart relating to the plate making operation, FIG. 4 is a flowchart relating to the plate making operation of the first drum 5A, FIG. 5 is a flowchart relating to the plate making operation of the second drum 5B, FIGS. 6 and 7 are timing charts during the plate making operation, FIG. FIG. 5 is a schematic diagram showing the operation of a platen motor at the time of plate making with the first drum 5A and the second drum 5B.
[0062]
In the initial state before performing the thermal stencil making of the desired image on the stencil sheet 2, the upstream movable guide plate upper limit sensor 62 and the downstream movable guide plate upper limit sensor 64 are ON. For this reason, as shown by the solid line in FIG. 1, both movable guide plates 46 and 53 are positioned horizontally so as to be aligned with both fixed guide plates 41 and 50.
[0063]
In this state, the control means 61 monitors the plate making request command of each of the first drum 5A and the second drum 5B. Then, when a prepress request command is received, a prepress operation for the drum 5 is performed.
[0064]
That is, when a plate making request command for performing the plate making operation on the first drum 5A side is sent (ST1-Yes), the plate making operation on the first drum 5A side is executed (ST2). When a plate making request command for performing the plate making operation on the second drum 5B side is sent (ST1-No), the plate making operation on the second drum side is executed (ST3).
[0065]
(First drum 5A side plate making operation: operation flowchart of FIG. 4)
As shown in FIG. 6, when the VSYNC signal is turned on as a synchronization signal (ST11-Yes), the platen motor 66 and the feed motor 68 are turned on and driven (ST12). Thereby, writing of a desired image on the stencil sheet 2 (thermal stencil making) is started. From this state, the platen motor 66 is driven continuously for γ seconds as shown in FIGS. In the meantime, as shown in FIG. 6, when the upstream stencil sheet standby sensor 44 is turned on (ST13-Yes), the timer 61a starts time measurement.
[0066]
Then, when the timer 61a elapses α seconds (ST14), the stencil sheet 2 enters the non-common transport path 56 (the first drum 5A side). In this state, the plate making drive speed of the platen motor 66 is controlled to be low as shown by the broken line in FIG. 8 (ST15) so that the actual plate making speed is kept constant. Specifically, when the stencil driving speed of the platen motor 66 is 100% when the stencil sheet 2 is conveyed in the common conveyance path 49, the stencil driving speed is controlled to be several percent lower than that. .
[0067]
After the speed of the platen motor 66 is reduced, as shown in FIG. 6, when the downstream stencil sheet standby sensor 52 is turned on (ST16-Yes), the timer 61a starts measuring time. Then, when β seconds elapse (ST17), the feed motor 68 is turned off and stopped. Then, the downstream side movable guide motor 72 is driven to move the downstream side movable guide plate 53 to the lower limit position shown by the dotted line in FIG. 1 (ST18).
[0068]
When the downstream movable guide plate 53 moves to the lower limit position and the downstream movable guide plate lower limit sensor 65 is turned on (ST19-Yes), the feed motor 68 is turned on and driven again (ST20). Subsequently, when the downstream stencil sheet feed sensor 55 is turned ON (ST21-Yes), the timer 61a starts measuring time. When δ seconds have elapsed from the timer 61a (ST22), the feed motor 68 is turned off and stopped (ST23). Then, when the platen motor operation time exceeds γ seconds by the time measurement of the timer 61a (ST24-Yes), the platen motor 66 is turned off and stopped (ST25). After that, the operation shifts to the plate receiving operation (ST26).
[0069]
In the plate making operation, one end of the stencil sheet 2 after the stencil transported by the stencil making operation is clamped to the clamp mechanism 7 of the first drum 5A. Then, the end of the clamped stencil sheet 2 is cut by the cutter device 45. Then, the drum 5A is rotated in the counterclockwise direction in FIG. 1, and the stencil sheet 2 having been made stencil is wound around the peripheral wall 6 of the first drum 5A.
[0070]
(Second drum 5B side plate making operation: operation flowchart of FIG. 5)
As shown in FIG. 7, when the VSYNC signal is turned on as a synchronization signal (ST31-Yes), the platen motor 66 and the feed motor 68 are turned on and driven (ST32). Thus, writing of the desired image on the stencil sheet 2 is started. From this state, the platen motor 66 is driven continuously for γ seconds as shown in FIGS. In the meantime, as shown in FIG. 7, when the upstream stencil sheet standby sensor 44 is turned on (ST33-Yes), the timer 61a starts measuring time.
[0071]
Then, when the timer 61a elapses α seconds (ST34), the feed motor 59 is turned off and stopped. Then, the upstream side movable guide motor 70 is driven to move the upstream side movable guide plate 46 to the lower limit position shown by the dotted line in FIG. 1 (ST35).
[0072]
When the upstream movable guide plate 46 moves to the lower limit position and the upstream movable guide plate lower limit sensor 65 is turned on (ST36-Yes), the feed motor 68 is turned on and driven again (ST37). Subsequently, when the upstream stencil sheet feed sensor 48 is turned on (ST38-Yes), the timer 61a starts measuring time. When the timer 61a elapses δ seconds (ST39), the feed motor 68 is turned off and stopped (ST40). Then, when the platen motor operation time exceeds γ seconds by the time measurement of the timer 61a (ST41-Yes), the platen motor 66 is turned off and stopped (ST42). After that, the operation shifts to the plate receiving operation (ST43).
[0073]
In the plate-making operation, one end of the stencil sheet 2 having been stencil conveyed by the above-described stencil making operation is clamped by the clamp mechanism 7 of the second drum 5B. Then, the drum 5B is rotated by a predetermined amount in the counterclockwise direction in FIG. 1, and the end of the stencil sheet 2 is cut by the cutter device 45. Thereafter, the drum 5B is further rotated in the counterclockwise direction in FIG. 1, and the stencil sheet 2 having been made stencil is wound around the peripheral wall 6 of the second drum 5B.
[0074]
When the stencil making operation and the stencil printing operation of the stencil sheet 2 have been completed, the printing operation is started. In this printing operation, the number of prints is input by operating the ten keys on an operation panel (not shown), and then, when the start key is pressed, the peripheral walls 6 of the first drum 5A and the second drum 5B rotate synchronously in the counterclockwise direction in FIG. Driven. At the same time, the back pushing roller 13 is also driven to rotate synchronously around its own central axis.
[0075]
When the peripheral wall 6 of each of the drums 5A and 5B and the backing roller 13 start rotating, the printing paper 3 is fed one by one from the paper feeding table 22 by the paper feeding roller 24 via the conveying roller 25 at a predetermined timing. Is sent to the clamp piece 16. The printing paper 3 clamped by the clamp pieces 16 of the back-press roller 13 together with the stencil sheet 2 wound around the outer peripheral surface of the plate cylinder of the first drum 5A has a predetermined pressing force between the back press roller 13 and the stencil sheet 2. It is pinched by.
[0076]
Then, a desired image is printed on the printing paper 3 by the stencil sheet 2 wound around the first drum 5A. Thereafter, the printing paper 3 is sandwiched between the backing roller 13 and the stencil sheet 2 wound around the second drum 5B with a predetermined pressing force.
[0077]
Then, a desired image is printed on the printing paper 3 by the stencil sheet 2 wound around the second drum 5B. The printing paper 3 on which the desired image is printed by the stencil paper 2 wound around each of the drums 5A and 5B is separated from the backing roller 13 by the printing paper separating claw 26. Then, the sheet is discharged to the sheet discharge table 29 via the sheet discharge device 27.
[0078]
Here, FIG. 9 is a diagram showing the plate making speed at the time of the first drum side plate making before the improvement in the stencil printing apparatus 1, and FIG. 10 is a comparison diagram of the transport amount of one stencil sheet 2 before and after the improvement. . Note that the transport speed of the stencil sheet in FIG. 9 is obtained by measuring at the position of the transport roller 57 in FIG. 1, and is considered to be equal to the actual plate making speed. The transport amount of the stencil sheet shown in FIG. 10 is an average value when stencil making is performed six times.
[0079]
When the stencil printing apparatus 1 having the configuration shown in FIG. 1 is constructed, the feed motor 68, which is the drive source of the non-common transport path 56, is set to be faster than the platen motor 66. Moreover, the non-common transport path 56 for the stencil sheet 2 on the first drum 5A side is longer than the common transport path 49 for the stencil sheet 2 on the second drum 5B side. Therefore, when the stencil sheet 2 is conveyed along the non-common conveyance path 56 on the first drum 5A side, the stencil sheet making speed of the stencil sheet 2 is increased, and the stencil sheet 2 of the stencil making section 4 is dragged. Actually, as can be seen from FIG. 9, the stencil sheet 2 has a non-common stencil path 2 compared to the stencil making speed of the stencil sheet 2 when the stencil sheet 2 is being conveyed along the common conveyance path 49 (section A in FIG. When the sheet 56 is conveyed (section B in FIG. 9), the stencil sheet making speed of the stencil sheet 2 is higher. As a result, greater image elongation occurs when making a plate on the first drum 5A than when making a plate on the second drum 5B.
[0080]
Therefore, in the present embodiment, when making a stencil sheet on the first drum 5A side, it is detected that the stencil sheet 2 has passed through the non-common transport path 56, and the stencil driving speed of the platen motor 66 at this time is reduced. Let it. As a result, image expansion during plate making of the first drum 5A is prevented. In the plate making on the second drum 5B side, the plate making drive speed of the platen motor 66 is not changed.
[0081]
In addition, the transport amount of the stencil sheet 2 before the improvement is different between the first drum 5A and the second drum 5B, and the image is elongated on the first drum 5A. On the other hand, according to the embodiment after the improvement, the difference in the transport amount of the stencil sheet 2 between the first drum 5A and the second drum 5B is small, and the image elongation on the first drum 5A side can be suppressed. did it. As shown in FIG. 10, before the improvement, there is a large difference in the transport amount of the stencil sheet 2 on the first drum 5A side and the second drum 5B side, but in the present embodiment after the improvement, the difference becomes small. It can be seen that the plate making speed was constant and the image elongation was suppressed.
[0082]
As described above, according to the present embodiment, an optimal stencil driving speed is set for each transport path (common transport path 49, non-common transport path 56) of the stencil sheet 2, and the passing point of the stencil sheet 2 is determined by the sensor ( The actual stencil making speed of the platen motor 66 can be controlled to be constant while being detected by the stencil stencil standby sensors 44 and 52 and the stencil stencil feed sensors 48 and 55). This makes it possible to provide a stencil printing apparatus that does not obliquely move the stencil sheet, eliminates image elongation, and does not prolong stencil making time. In addition, a printed matter free from misregistration can be obtained even in multi-color and multi-plate printing.
[0083]
The above embodiment is not limited to a stencil printing machine having a configuration in which a backing roller used commonly for the two drums 5A and 5B is provided. For example, the present invention can be applied to a stencil printing apparatus as shown in FIG. In this stencil printing apparatus, press rollers 81, 81 as roller members capable of moving up and down are arranged in parallel with the center axis direction of each of the drums 5A, 5B so as to press and contact the peripheral wall 6 of each of the drums 5A, 5B. ing. Then, stencil printing is performed by pressing the printing paper 3 fed from the paper feeding unit 21 against the peripheral wall 6 by press rollers 81 and 81. At this time, the transfer of the printing paper 3 from the first drum 5A to the second drum 5B is performed by a plurality of roller pairs 82a provided between the first drum 5A and the second drum 5B and the guide, as shown in FIG. This is performed via a transport mechanism 82 having a plate 82b.
[0084]
Although the above-described embodiment has been described with respect to an example in which two-color stencil printing is performed once, a stencil printing apparatus configured to further include a plurality of drums and perform multi-color stencil printing once. It is also possible to apply. Further, the present invention can be applied to a stencil printing apparatus which performs a single-color stencil printing in which a stencil sheet transport path to a drum is long and an image expands and contracts. In this case, the first drum 5A is removed and only the second drum 5B is provided. Therefore, the transport route is only the non-common transport route 56. The detecting means includes an upstream stencil sheet standby sensor 44 and an upstream stencil sheet feed sensor 48.
[0085]
In the above embodiment, the passage of the stencil sheet 2 conveyed on the conveyance path (the common conveyance path 49, the non-common conveyance path 56) is detected by a plurality of sensors (stencil stencil standby sensor, stencil stencil feed sensor). Although the configuration has been described, the stencil sheet feed amount from a predetermined position may be detected based on the output of an encoder connected to the feed motor 68.
[0086]
【The invention's effect】
As is apparent from the above description, according to the present invention, an optimal stencil making speed is set for each stencil sheet conveyance path (common conveyance path, non-common conveyance path), and the platen is detected while detecting the passing point of the stencil sheet. The actual plate making speed of the motor can be controlled to be constant. This makes it possible to provide a stencil printing apparatus that does not obliquely move the stencil sheet, eliminates image elongation, and does not prolong stencil making time. In addition, a printed matter free from misregistration can be obtained even in multi-color and multi-plate printing.
[Brief description of the drawings]
FIG. 1 shows a schematic configuration of a stencil printing apparatus according to the present invention.
FIG. 2 is a block diagram of a stencil printing apparatus according to the present invention, which is related to stencil conveyance control.
FIG. 3 is a main flowchart relating to a stencil making operation of the stencil printing machine according to the present invention.
FIG. 4 is a flowchart illustrating a plate making operation of a first drum of the stencil printing apparatus according to the present invention.
FIG. 5 is a flowchart relating to a plate making operation of a second drum of the stencil printing apparatus according to the present invention.
FIG. 6 is a timing chart at the time of stencil making operation of the first drum 5A side of the stencil printing apparatus according to the present invention.
FIG. 7 is a timing chart of the stencil printing apparatus according to the present invention at the time of stencil making operation on the second drum 5B side.
FIG. 8 is a schematic view showing the operation of a platen motor when making a stencil on the first and second drums of the stencil printing apparatus according to the present invention.
9 is a diagram showing a stencil making speed at the time of stencil making at the first drum side before improvement in the stencil printing machine of FIG. 1;
FIG. 10 is a comparison diagram of the conveyance amount of one stencil sheet before and after the improvement.
FIG. 11 is a diagram showing another embodiment of a stencil printing apparatus according to the present invention.
[Explanation of symbols]
31: thermal head, 32: platen roller, 2: stencil paper, 4: plate making section,
49: conveying path (common conveying path), 61: control means, 5 (5A, 5B): cylindrical drum, 56: non-common conveying path, 44, 48, 52, 55: detecting means,
41 ... upstream fixed guide plate, 7 ... clamp mechanism, 46 ... upstream movable guide plate,
50: Downstream fixed guide plate, 53: Downstream movable guide plate

Claims (3)

A thermal head, a plate-making section comprising a platen roller provided at a position facing the thermal head, and a perforating section for perforating a desired image while conveying a stencil sheet by rotating the platen roller,
A plurality of cylindrical drums around which the perforated stencil sheet can be wound;
A common transport path commonly used for all drums when transporting and winding the stencil sheet made to any one of the drums, and a non-common transport path communicating with the common transport path. Transport path,
A transport unit that transports the stencil sheet that has been made at a predetermined speed on the transport path,
Detecting means for detecting the passage of the stencil sheet at a predetermined position of the transport path;
Control means for controlling the driving speed of the platen roller in the plate making section at a low speed when it is determined from the detection signal of the detection means that the stencil sheet has been transported at the boundary between the common transport path and the non-common transport path,
A stencil printing apparatus comprising: The common transport path,
An upstream fixed guide plate, one end of which is in communication with the stencil making section and is disposed to face the stencil sheet at an interval allowing passage of the stencil sheet;
One end is communicated with the other end of the upstream-side fixed guide plate, and the other end is opposed to the stencil sheet at an interval allowing passage of the stencil sheet such that the other end is communicated with the non-common transport path or the clamp mechanism of the drum. Upstream movable guide plate,
Consisting of
The non-common transport path,
A downstream fixed guide plate, one end of which is in communication with the common transport path and is opposed to the stencil sheet at an interval allowing passage of the stencil sheet;
A downstream movable guide plate, one end of which is communicated with the other end of the downstream fixed guide plate, and the other end of which is opposed to the stencil paper at an interval allowing passage of the stencil paper so as to be able to communicate with the clamp mechanism of the drum;
The stencil printing apparatus according to claim 1, comprising: Stencil making a desired image while transporting the stencil paper,
When the stencil sheet is conveyed and wound to any one of a plurality of cylindrical drums, a common conveyance path commonly used for all the drums, and a non-communication path communicating with the common conveyance path. A common transport path, on the transport path of the stencil sheet consisting of, to transport the stencil sheet made at a predetermined speed,
When the passage of the stencil sheet in the common conveyance path and the non-common conveyance path is detected, and it is determined that the stencil sheet has been conveyed at the boundary between the common conveyance path and the non-common conveyance path, the conveyance of the stencil sheet is performed. Reduce the speed,
A method of conveying a stencil sheet for a stencil printing apparatus, comprising winding the stencil sheet around a cylindrical drum.

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