JPH0220427B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a silk screen printing or textile printing machine, preferably of the type that is equipped with an endless conveyor as means for transporting the material. Such a conveyor normally operates as follows: it stops at a setting position (first position) for positioning the material for printing (aligning the front and back printing surfaces); It is driven by a drive means such as a motor that functions to transport the printer to a predetermined printing position, and a flat support surface set at a lower position allows the setting position and the printing position ( printing position).

As is well known, various examples are known in the industry regarding silk screen printing machines of the type that are equipped with endless conveyors as means for transporting materials. One example is Swedish Patent No. 383487, which describes a rotary printing press for band-like materials, especially textiles, which includes a drive disk for a plurality of printing rollers and a mechanical transformer. An arrangement is disclosed with an endless support belt driven by a transmission. The specification of this patent further includes synchronization means for controlling the support belt in accordance with the movement of the printing roller;
Lifting means are disclosed for separating the roller from the belt.

The tuning means shown in that patent comprises a rotary pulse generator, which is arranged to be driven by a sensing wheel which rests on the above-mentioned support belt. Further, the above-mentioned generator is adapted to generate pulses corresponding to the traveling speed of the above-mentioned support belt. Amplifiers and pulse converters provided to amplify and convert the pulses provided by such generators drive stepping motors and four-way valves to control oil flow. are working in This oil flow occurs due to the movement of the internal thread or nut, which is driven by the stepping motor described above through a reduction gear.

The above-mentioned type of silk screen printing machine is capable of accurately printing in accordance with the stencil pattern while moving an endless conveyor belt, which is a means of conveying the material, between the setting position and the printing position. to be required,
It has been recognized that it involves a series of technical problems.

For example, in similar printing machines, after the material for printing has been set in the initial setting position on the conveyor belt, the conveyor belt can be moved to avoid the need for repositioning. It must be possible to accurately transport the paper to a predetermined printing position. This means that if the printing material is moved over a distance of more than 10 m between the setting position and the printing position, the material must be moved in such a way that it can be matched to the stencil pattern with the highest degree of accuracy. This is also important because it is necessary to transport it to the above printing position by moving it within an error range of 0.5 mm or 0.1 mm or less. In addition, in this case, it must be taken into account that the above-mentioned error regarding the moving distance of the material tends to increase depending on the conveyance speed of the printing material.

Another problem that has been identified with conventional silk screen printing machines, or those of the type described above, is that when the material is relatively thin, it is difficult to place it in the desired setting position. One example of this is that positioning operations become difficult. In the case of such materials, i.e. soft materials, the frictional action on the belt described above tends to cause the material to be attracted to the upper surface of the belt, so that by means of known setting means, It is difficult to position the material at a predetermined setting position simply by applying a positioning force to the edge of the material.

The first problem raised is primarily due to the fact that the two ends of the belt are connected by a splice or seam; From experience, it is said that it is impossible to make all materials of the same quality. Moreover, such a belt is
Not only is it wound around multiple rollers such as a drive roller, end roller, and linking roller, but it is also moved exclusively in one direction during operation.
When the above-mentioned seam portion (seam portion) passes over each of these rollers, the rotation radius of the belt at that location changes. Such a condition is particularly noticeable with respect to the drive roller and the end roller.

Among the rollers mentioned above, the drive roller and the end roller have a fairly large diameter of about 200 mm. Therefore, even if a relatively small change in the rotation radius of the conveyor belt as described above occurs, a non-negligible error occurs in the printing position. In this case, the errors caused by the belt are calculated between the material setting position and the printing position according to known methods. Similarly, the above error calculation can also be performed between the drive roller or the end roller.
According to experience, the change in the rotation radius of the above rollers is
It has been revealed that even if the size is on the order of 0.1 mm, the error on the conveyor will be on the order of 0.3 mm for each half rotation of each roller.

It has been recognized that the silk screen printing machines described above have the additional disadvantage that it is difficult to position the material in a predetermined printing position, since the printing position depends on two different parameters. In other words,
The above-mentioned conveyor moves accurately between the initial setting position and the printing position, but in doing so, it is possible to very rigorously evaluate the distance traveled between the various means of transporting materials. Not only must the material be moved from its setting position to the printing position,
The center position of the conveyor belt must not shift.

When it comes to positioning thin materials, especially very thin and fragile materials such as glass, in the above-mentioned printing locations, it is possible to prevent cracks in the material itself by applying positioning means to the edges of such material. must also be taken into consideration. Otherwise, frictional and adhesive forces between the printing material and the conveyor belt make it difficult to convey the material accurately along the conveyor belt.

In addition to the above, when conveying glassy material to a printing position, it may be conveyed to a predetermined setting position along the direction of travel of the conveyor belt at a speed greater than the moving speed of the conveyor belt. New problems arise based on the fact that This means that there is a risk that the leading edge of the material will collide with the setting means mentioned above. Therefore, when transporting a vitreous material to a setting position, it is required to absorb the kinetic energy imparted to the material during the transport. Hitherto, due to the lack of such measures, glassy materials often suffer from cracking and breakage due to collision with known setting means.

The problem mentioned above is that the printing press has an endless conveyor belt as a material conveyance means, and the conveyor belt stops at the initial setting position for positioning the material. In a silk screen printing machine, the movement of the conveyor belt for the printing material is controlled by its error. This can be achieved by detecting with a movement width detection means whose range is set to 0.5 mm, preferably 0.1 mm or less. The detection means for this purpose is a part of the present invention, and is based on the conveyance distance from the initial setting position (first position) to the next printing position (second position), and is based on a preset counter. connected to. This counter is operative to generate an activation signal for stopping the drive means of the conveyor belt when it has precisely reached the above-mentioned second or printing position.

On the other hand, if conveying the material from its setting position to the printing position itself has strong acceleration performance, it can achieve substantial constant speed movement and rapid deceleration function, and the setting operation of the material is the final step. This is provided by the configuration of this invention which is designed to be carried out at extremely low speeds.

Other problems can also be achieved by applying a fluid to the underside of the material in the first or setting position. This fluid reduces the frictional forces acting between the material and its supporting surface, such as a printing table or conveyor belt, and transports the material along the supporting surface to the desired printing position. useful for doing. When the material reaches the printing position, a negative pressure is applied to the underside of the material, which increases the frictional force between the material and the support surface.
Such negative pressure is maintained over the entire length of the material being conveyed to the printing position.

The features of this invention will become clear from the description of the following embodiments.

The drawings will be explained below.

The silk screen printing machine according to the invention is, as previously described, a number of improvements over the type which is equipped with an endless conveyor belt which provides a supporting surface for the printing material. Therefore, a description of the basic operating mode and constituent parts of the above-mentioned printing press indicated by general reference numeral 1 is omitted. The conveyor belt 2, which serves as a means for transporting materials, is designed so that materials can be placed on its upper surface. In this embodiment, the material conveyed by the conveyor 2 is a thin glass material. Such material 3 is used in the frame 1' of the printing press described above.
ie, a setting position for aligning the front and back printed surfaces.

The conveyor belt 2 is arranged to be driven by a drive means (not shown in Figure 1) which is a DC motor. This drive means or motor is controlled via a thyristor (foursquare type) to stop the conveyor belt 2 in the initial setting position for positioning the material 3 for printing, as shown in FIG. After that, it operates as if it were moved toward the next printing position. As a result, the material placed in the printing position is labeled 3'. Printing corresponding to the pattern of the stencil is performed there, but the structure of the stencil itself is not shown for simplicity of construction. However, it will be appreciated that such a stencil is one that is stretched within the frame 4. Ink is applied to the above-mentioned stencil from its upper surface via a squeegee 5 through a number of holes formed in the stencil, thereby producing the desired print on the material 3' at the printing position. It's starting to get rubbed.

The above-mentioned stencil is fixed relative to its frame 4 in printing machines of this type. For this reason, the position of the material 3' must be such that it corresponds exactly to the predetermined printing position. For the same reason, it is also important that the distance of the material 3 moving from the setting position in Figure 1 to the printing position in Figure 2 is evaluated or calculated correctly (with an error of about 1/10 of 1 mm). .

The material 3 in the position shown in FIG. is applied. Manipulation of the position of the material 3 in such a state involves both side edge portions 3a, 3b of the material.
This is made very easy by means of the positioning means or setting means 6, 7, which are engaged with each other. In addition to these setting means, the other side edge portion 3 of the material 3
Setting means 8 and 9 are also installed at c. Those four setting means 6, 7, 8
and 9, it becomes possible to accurately position the material 3 at a predetermined setting position while applying a negligibly small frictional force between the material 3 and the conveyor belt 2. The magnitude of the frictional force in this case is determined for various materials in order to achieve accurate setting operation of the material 3.
It should be determined empirically by adjusting the amount of fluid to be applied to the bottom surface of the material.

After the material 3 has been positioned at a predetermined setting position by the setting means 6, 7, 8 and 9, the material 3 is placed on a supporting surface or conveyor belt 2.
An operation is required to increase the frictional force acting between the material 3 and the upper surface, which operation is adapted to be carried out by means of a negative pressure below the material 3. Such a negative pressure is maintained throughout the distance traveled by the material 3 towards the printing position shown in FIG. 2 and until the end of the printing process.

As previously explained, the support surface for the material 3 is provided by the entress conveyor belt 2. It is desirable that such belts be processed so as to have as little variation in thickness as possible.

A support means, ie a printing table, is installed below the conveyor belt 2. This table is divided into multiple parts. Therefore, the running range of the conveyor belt 2 extends over the entire length of the printing table. Such printing tables and conveyor belts include
A large number of holes are provided.

Although only a portion of the printing table described above is shown in FIG. 3, as can be inferred from this, it has a plurality of divided portions. A pipe is connected to each of these divided parts separately, such as pipe 10 for divided part 10', pipe 11 for divided part 11', or pipe 12 for divided part 12'. There is. Among them, the first three sections connected to pipes 10, 11 and 12 are made of material 3 in FIG.
is located below. A hose 10a is connected to the pipe 10, a hose 11a is connected to the pipe 11, and a hose 12a is connected to the pipe 12 (first
(see figure). Each of these hoses 10a, 11a,
12a is further connected to valve means as shown in FIG. The figure shows how the hose 10a is connected to the valve means 20,
Connected to pipe 21 for supply of fluid, which is compressed air, or pipe 2 for an auxiliary pressure source
2 is shown. A control valve (not shown) can be connected to the pipes 21 and 22 so arranged.

When the valve 20 is in the position shown, compressed air, i.e. overpressure, is supplied to the hose 10a or to the hoses 11a, 12a, due to the pipe 21 corresponding to the bore 20a of the valve; In this case, as described above, an air cushion is formed under the material 3. In this state, after the material is positioned, the valve 20 is adjusted so that the hole 20a of the valve corresponds to the pipe 22, so that negative pressure is applied to the lower side of the material 3. The frictional force between the material and the conveyor belt 2 increases.

When the material 3 is conveyed by the conveyor belt 2 to the printing position shown in FIG. 2, hoses (only the hose 13a is shown in FIG. As the material 3 moves, the materials 3 become connected to the negative pressure source one after another. Such operation is by means of valve 17 shown in FIG. The above-mentioned negative pressure is introduced to the connector 18 of this valve 17, and the valve body 19 of the valve is rotatably provided in the direction of the arrow in the figure. Accordingly, the divided parts 13, 14,
15, etc., by rotating the valve 17, negative pressure is applied in stages until the material is conveyed to the printing position shown in FIG.

In the method described above, only the divided portion installed below the material 3 is
The other divisions, namely the divisions on the printing table side, are associated with the second valve shown in FIG. It is about to be installed. This second valve is located below the material being conveyed along the printing table to the printing position in FIG. According to the above configuration, the rotation of the valve body 19 on the stationary part and the seal plate 19a located at the intermediate position is controlled in relation to the movement of the conveyor belt 2 or the operation of the drive source of the conveyor belt via the transmission. It should be understood that this is something that should be done.

When the material 3 reaches the predetermined setting position in FIG. The entire material is then positioned via the air cushion described above so that it occupies the correct setting position. When the first valve shown in FIG. 5 is operated after a desired setting operation, negative pressure is applied to the lower division of the material.

Material 3 to the setting position shown in Figure 1
the positioning operation is simultaneous with the printing operation of the material 3', which precedes the printing position shown in FIG.
It is preferable that the process be performed at a later date or at a somewhat earlier time than that.

As mentioned above, printing materials are transported from a predetermined setting position (see Figure 1) to a printing position (see Figure 2), but the practical transport pattern involves rapid There are several steps of acceleration, substantially constant motion, and rapid deceleration, followed by a very gradual slow motion in the final stage. First, in the above-mentioned low-speed movement section, in a state where the leading side edge portion 3c of the material is applied to the setting means 8, 9 located in the front position, both side edge portions 3c of the material are set.
Setting means 6, 7 on both sides operate to position a, 3b. This allows the entire material 3 to be positioned before the conveyor belt 2 stops. The conveyor belt is then sliding beneath the material 3. Setting means 8 and 9 for positioning the leading side edge portion 3c are movably installed so as to follow external forces. Therefore, when the conveyor belt 2 moves rapidly to the printing position,
The energy imparted to the materials 3 will be absorbed by their setting means.

The positioning operation of the material in the printing position is adapted to take place during the slow transport movement. As is clear from this, the spring members for the setting means 8, 9 have sufficient strength to hold the material 3 in the predetermined setting position even when the belt 2 is moving. It is desirable that

In order to accurately position the material 3 in the printing position shown in FIG. 2, one condition is that the conveyor 2 is moved so as not to be off-centered.
A plurality of guide means 25 are provided for this purpose against the edge 2a of the conveyor belt 2.
These guide means are adapted to be guided by bars 26, 27 fixed to the conveyor belt.

FIG. 7 shows a cross-sectional view of the edge 2a of the conveyor belt 2, showing the slide plate 28 installed in the upper position of the belt. This plate is attached to the conveyor belt 2 by bolts 29. A counter plate 30 is attached to the opposite side of the plate with the belt 2 interposed therebetween by bolts 29 and nuts 31, and
Ball bearings 32, 32' are mounted via a sleeve 33 around the bolt 29.

In such an arrangement, the ball bearings 32, 32' can move along the bars or rails 27 shown. Since one rail is provided for each edge 2a on both sides of the belt 2, the belt 2 moves accurately along the rails without causing any deviation in the center position.

In connection with the purpose of evaluating or calculating with small errors the movement of the material from the setting position shown in FIG. 1 to the printing position shown in FIG. This can be detected by the means 40. This detection means is installed in cooperation with the belt 2 at a suitable position between the setting position and the printing position, and is an optical shaft encoder, i.e., optically generates an encoded output signal. It consists of a device configured as follows. Such devices include, for example, the type OM ₂₅ offered by the American company "Data Technologies" Iuc. Mass., which produces 2500 pulses per revolution. The shaft 41 in the above detection means has a circumferential surface 42a.
The wheel 42 is machined into a gear shape. The diameter of this wheel is sized to produce one pulse on line 43 for each small length section. In the example shown, each pulse corresponds to a travel width of the conveyor belt 2 of 0.1 mm. line 43
For example, California (NLS) non-. linear. Electronics manufactured by System Corp. Digital. Preset. Counter, model: Connected to PR-S.
As is clear from FIG. 8, the wheel 42 is in contact with the conveyor belt 2. This type of connection serves to detect the distance traveled by the material 3 as it is conveyed by the belt 2 from the setting position shown in FIG. 1 to the printing position shown in FIG. Connected to line 42 is an electrical counter 44 which is configured to count small lengthwise sections.

It is actually possible to set the above-mentioned counter to a predetermined value and to make the value correspond to the moving distance of the material from a predetermined setting position to the printing position. When counter 44 reaches a certain value, an activation signal is then generated via line 45. This signal can be applied to, for example, the dc motor 46
When the material 3 reaches exactly the printing position shown in FIG. 2, said drive source is stopped.

As mentioned above, the material 3 is adapted to be conveyed from its setting position to the printing position through several steps. This is the 10th
In the figure, the time period is as follows: a is the section with rapid acceleration, b and c are the sections with substantially constant motion and rapid deceleration, and d is the section with very gentle low-speed motion at the end stage. It is represented by a chart.

As the control means 47, for example, GME-System AB located in Stockholm, Kingdom of Sweden is used.
A thyristor controller manufactured by , Inc. can be used. Such control means function to control the drive source during the period in which each of the steps described above is performed. Further, the above-mentioned thyristor is configured to drive the DC motor in either direction by means of sinus oscillation.

According to the counter 44, the thyristor controller and the drive source or drive means 46 can be controlled via the line 45 during the period of the low-speed movement and, on the basis of the set value of the counter, can be controlled immediately. The drive source can be stopped.

In this embodiment, the running length of the conveyor 2 is approximately
1.26m, the number of counters 44 was set to 12,600, and as the belt at the position shown in Figure 1 began to move, the number of pulses generated one after another was counted, and the value reached 12,585. At this point, the operating speed of the drive source 46 that was operating until then slows down, and when the above value reaches 12,600, a stop signal for that drive source is generated. Therefore, when the count number by the counter 44 reaches 12585, the above drive source is
It works to drive the belt 2 at a very low speed. The delay between the guide signal (advance signal) and the stop signal for belt 2 can be compensated for by lowering the counter setting.

A switch (not shown) is connected to the drive source 46. The drive source 44 driven through this switch drives a drive wheel 46a connected to the belt 2 in a well-known manner. The drive system or connection type for this purpose has been omitted.

When the drive source described above is activated, a rapid accelerating movement and a substantially constant movement is imparted to the belt 2, and then over the section indicated by e in FIG. 10, the drive wheel After 46a is rotated, the other switches 48 (see FIG. 9) are activated. The command from this switch is then transmitted to the control means 47 via line 49.
As a result, it should be understood from the previous explanation that the drive source 46 operates as described above via the control means 47 during the section f in FIG.

In the above section f, a separately installed hydraulic piston-cylinder device 50 is designed to operate (see FIG. 9). This device is adapted to engage a stop 51 on the cam disk shown. That cam disc 52
The wheels 46a are connected to each other by suitable friction couplings.
is fixed. Such a configuration is for preventing the cam disk 52 from rotating following the wheel 46a in the section from f to j shown in FIG. It is possible to carry out a precise positioning operation of the material 3 relative to its position between each of these f and j points. In particular, according to such a configuration,
biasing the printing material to the same position during each cycle;
The advantage is that the acceleration, substantially constant and deceleration movements described above are performed in sequence, yet ensuring that the material occupies a precise position during the slow movement described above. Furthermore, the configuration of the cam disc 52 described above facilitates rapid movement of material to and from the setting position described above.

In the configuration of the invention, it is possible to apply a suitable conveyor belt as a support means with a flat upper side, which makes it possible to use no fluid pressure on the underside of the material for printing. or only requires very little pressure to help position the material in a predetermined setting position.

Such belts, when conveying the above materials,
This provides the benefit of effective negative pressure.

The valve used in the printing press of the present invention, that is, the valve that acts on the divided parts of the printing table other than the divided part at the above-mentioned setting position, is used when the material is conveyed by the above-mentioned belt. Only works to provide negative pressure above. Thereby, the material is transported precisely from its setting position to the printing position in the area of application of the negative pressure, which corresponds to the length of the material and thus to the distance of movement of the material.

If you want to limit or divide the above area especially in the direction perpendicular to the printing table,
As shown in FIGS. 3a and 3b, the table itself can be divided into several sections, and the negative pressure described above can be applied to each section depending on the width of the material. As a way to do this, the above valve D is divided into sections A, B, and C.
It is desirable to provide separate information for each.

According to this invention, since the moving distance of the printing material is accurately detected by the detection means,
The material can be easily positioned with respect to a predetermined setting position and printing position, and since the detection means and the counter are connected, the moving distance of the material can be easily and accurately determined depending on the size of the material. will be adjusted. Furthermore, the present invention allows for adjustment of the frictional force between the printing material and its supporting surface, thereby making it possible to easily position even fairly thin or glassy materials without causing damage. In addition to the operation, by operating the movable setting means to which the side edge portion of the leading side of the material is applied, the kinetic energy imparted to the material is absorbed or alleviated, and the printing position is adjusted. The setting of the position of the material at is carried out with the necessary precision.

As explained above, according to the present invention, the endless conveyor belt 2 is used as a material conveying means, and in the first position, the material 3 is manipulated by the positioning means, so that the material 3 is placed on the surface of the conveyor belt 2. along and aligned. Thereafter, a negative pressure is transmitted through the holes in the conveyor belt 2, and the negative pressure acts on the material 3, and the material is held by the negative pressure. Then, the conveyor belt 2 is driven by the drive source, and the material 3 is conveyed from the first position to the printing position. Further, according to the present invention, the printing table is divided into parts A, B, and C arranged in the transport direction. In other words, the printing table is divided into a plurality of sections A, B, and C in a direction perpendicular to the conveyance direction of the material 3, that is, in the width direction of the material 3. When the material 3 is transported, only the lower part of the material 3 is connected to a negative pressure source. Therefore, even if the materials 3 have different widths,
Portion A connected to a negative pressure source according to the width of material 3,
By selecting B and C, negative pressure can be applied effectively and the material 3 can be held securely.
Even if the width of the material 3 is small, only the air on both sides of the material 3 is sucked in, and the problem that the material 3 is not held properly does not occur. There is also no loss of negative pressure source.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a part of the printing press according to the invention, FIG. 2 is a perspective view showing other parts of the printing press, and FIG. 3 is a partial perspective view showing the conveyor belt and printing table for the printing material. Floor plan, 3rd
Figure a is the overall plan view, Figure 3b is its side view,
FIG. 4 is a perspective view schematically showing the auxiliary pressure supply valve in the printing table, and FIG. 5 shows the fluid and negative pressure supply valve in the printing material setting position. FIG. 6 is a partial side view showing an arrangement for retaining the edge of the conveyor belt; FIG. 7 is a partial sectional view showing said arrangement in greater detail on an enlarged scale; FIG. , FIG. 8 is a schematic perspective view showing the drive system of the conveyor belt, FIG. 9 is a partial perspective view showing a cam disc and related parts incorporated in the drive system, and FIG. 10 is a schematic perspective view showing the drive system of the conveyor belt. This is a time chart showing how the belt is driven. 2...Conveyor belt, 3...Material, 8,9
... Setting means, 10-15 ... Divided portion, 17 ... Second valve, 20 ... First valve.

Claims (1)

[Scope of Claims] 1. An endless conveyor belt is provided as a material conveyance means, the belt is driven and controlled by a drive source, and the belt has a first position for aligning the material to be printed or textile-printed. a silk screen printing or textile printing machine of the type in which the material is conveyed to a printing position where the material is imparted with a pattern corresponding to the pattern of the screen; moves, the material is displaced along the support surface to the alignment position, and after alignment, the material is subjected to a high frictional force against the surface by negative pressure, and the material is conveyed to the printing position. When the high frictional force acts, the support surface consists of an endless conveyor belt with holes for transmitting negative pressure to the material, and the printing table is arranged in the conveying direction in parts A, B,
A printing or textile printing machine characterized in that the printing or textile printing machine is divided into C, and only the lower part of the material is connected to a negative pressure source during conveyance. 2. Using a printing table with a moving part of the conveyor belt, the part located below the material in the alignment position is connected to a first valve, and the first valve does not apply overpressure or under-pressure to the part. A silk screen printing or textile printing machine according to claim 1, which is adapted to generate pressure. 3. The remaining part of the printing table is connected to a second valve, so that when the material is conveyed on the printing table, the second valve is connected only to the lower part of the material. A silk screen printing or textile printing machine according to claim 2. 4. A silk screen printing or textile printing machine according to claim 2, wherein the first valve creates a negative pressure in the section after alignment of the material.