JPH09251202A - Block copy making device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a superimposing error by starting recording from the same position in periodicity, in any page images based on contents stored in a periodicity storage means at the time of recording plural page images. SOLUTION: For instance, when a recording paper 10 held between a thermal head 13 and a platen roller 14 is fed, the feed rate of the recording paper 10 for every round of the platen roller 14 can be regarded as the same feed rate. When the platen roller 14 has not complete roundness, a unit feed rate is made uneven during a round of the platen roller 14. The unevenness of the feed rate causes feeding unevenness as the total feeding unevenness of each element of a recording paper feeding system, since each element has a factor in the feeding unevenness, in a block copy making device. Therefore, the feeding unevenness (error) at this time has the periodicity. Thus, as the recording starting position of each page, the specific position of an error period is obtained so that the superimposing error can be minimized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block copy creating apparatus for printing an image created by a computer with a printer to create a block copy for printing. It relates to the improvement of plate overlay accuracy.

[0002]

2. Description of the Related Art Such a block making device is generally shown in FIG.
It had the structure shown in. Although FIG. 1 is also a diagram of one embodiment of the present invention, the structure of a conventional portion will be described here. In the figure, 10 is a recording sheet such as a sheet or film which is a printing plate by being directly drawn, 11 is a recording sheet stock roller for holding the recording sheet 10 in a roll shape, 11
Reference numeral 1 denotes a back tension mechanism for giving a predetermined back tension to the stock roller 11, 12 denotes a first guide roller for guiding the recording paper 10 of the stock roller 11,
13 is a thermal head as recording means, 14 is a platen roller, 15 is a second guide roller for guiding the recording paper 10, and 16 is a recording paper 1 in cooperation with a pinch roller 17.
0 is a feed roller, 18 is a paper feed motor for driving the feed roller 16, 19 is an encoder, 2
0 is a cutter mechanism, 21 is a back tension mechanism 111
Tension control circuit that adjusts the tension force of the paper, 22 is a constant speed control circuit that controls the paper feed motor 18, 23 is a cutter control circuit that drives the cutter mechanism 20, and 24 is the thermal head 13 that corresponds to the output of the encoder 19. It is a print control circuit to be driven.

Here, the recording paper stock roller 11, the first guide roller 12, the platen roller 14, the second guide roller 15, the feed roller 16, and other elements relating to the transfer of the recording paper 10 constitute the recording paper transfer system and the thermal head. 1
3 and the platen roller 14 respectively form a recording portion,
The cutter mechanism 20 operates as a cutting unit of the recording paper 10. Further, although not shown in FIG. 1, there is provided a control means for receiving signals from a computer or the like for creating an image signal and controlling the respective parts of the above-mentioned block making device.

In this block-making device, a page is recorded with a size corresponding to the size of the printing plate to be created. That is, one page record is a block copy corresponding to one printing plate. Therefore, for example, when creating a multicolor printing plate, a printing plate is often created for each "color" to be multicolor printed. For this reason, it is necessary for the block making device as described above to print a plurality of pages corresponding to the "colors" to be used to create a block for each "color". Then, a printing plate of each color is created from each of these plates.

In the above-mentioned conventional block making device, page recording is performed based on a command from a control means (not shown). This page recording is performed by a method similar to that of a normal printer, and recording is sequentially performed by the thermal head 13 every time the recording paper 10 is fed one step.

[0006]

However, in such a conventional block making method, an image may be misaligned at the write start portion, the center portion or the end portion of each of a plurality of page records. This is mainly because the recording paper transfer system has a paper feed periodicity. Therefore, by precisely matching the write start position of each page record with the specific position of this periodicity, this overlay error can be greatly reduced.

[0007]

Therefore, according to the present invention, a recording paper holding unit for holding a series of recording papers and a predetermined page image on the recording paper fed from the recording paper holding unit according to an image signal. , A recording paper cutting unit that cuts the page image recorded by the recording unit for each page, and the recording paper from the recording paper holding unit to the cutting unit through the recording unit to the cutting unit. In a block making device having a recording sheet transfer means for moving at a speed and a route, and a control means for controlling each of these elements to create a plurality of page images as a block copy, the control means is provided with the recording means. For any page image based on the contents stored in the periodicity storage means when recording a plurality of page images to be used as a block and the periodicity storage means for storing the periodicity of the transportation of the paper transporting means in advance. And recording position determining means for starting the recording from the same position of the periodicity were provided.

[0008]

As shown in FIG. 2, for example, the thermal head 1
Consider a case where the recording paper 10 sandwiched between the sheet 3 and the platen roller 14 is transported. The transfer amount of the recording paper 10 may be considered to be the same for each round of the platen roller 14, but if the platen roller 14 is not a perfect circle, the platen roller 1
During one round of 4, the unit feed amount becomes uneven.

In the plate making apparatus shown in FIG. 1, each of the elements of the recording paper transport system has a factor of such a feed unevenness. The unevenness occurs. This total feed unevenness (error) has a periodicity as shown in FIG. Therefore, the registration error can be minimized by setting the start position of each page recording to the specific position of the error period shown in FIG.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, the present invention is provided with a cueing circuit 25 for determining the start position of each page recording. The cueing circuit 25 is provided with a periodic storage means and a recording position determining means.

First Embodiment In the first embodiment of the present invention, the start position of each page recording is set to a fixed position with reference to the element of the recording paper transfer system which is the largest factor of the error period shown in FIG. Is. For example,
When the eccentricity of the feed roller 16 of the recording paper transfer system in FIG. 1 has the largest error factor, first, the encoder 19 measures the paper feed amount when the feed roller 16 makes one rotation. This measured value is stored in the periodic storage means.

Now, this measured value, that is, the feed roller 1
It is assumed that the outer circumference of 6 is "100 mm". In addition, the length of the block copy to be created, that is, the length of the page record is "250
mm ”. In this case, the recording position determining means adds a margin of "50 mm" for the first page recording,
The total page recording length is “300 mm”. Then, the second page is recorded from the position moved by "300 mm" from the start position of the first page recording. Similarly, 2
The third page is recorded from the position moved by "300 mm" from the start position of recording the third page.

As described above, by setting the length of the page recording (work block) to a length that is an integral multiple of the feeding cycle of the element having the largest error factor among the respective elements of the recording paper transfer system, Also for page recording, recording is started from the same position in the repetition cycle.

Second Embodiment The least common multiple of the error cycle of each element of the recording paper feed system shown in FIG. 1 is set as the entire error cycle of this recording paper feed system, and the page recording (block copy) of this block making device is performed. ) Set the length to an integer multiple of the total error period.

It is now assumed that the error cycle (for example, the roller outer circumference) of each element of the recording paper feeding system shown in FIG. 1 is as follows. That is, the feed roller 16 is "100 m
m ", each of the guide rollers 12 and 15 is" 50 m "
m ”, the platen roller 14 is“ 100 mm ”, the encoder 19 is“ 50 mm ”, and the pinch roller 17 is“ 20 mm ”.
mm ", the total error period of the paper feed system due to these is" 100 mm ".

Therefore, "100 mm" is used as a page recording length when creating a block with a length of "60 mm", and "200 mm" is used as a page recording length when creating a block with a length of "160 mm". Therefore, as in the first embodiment, by setting the page recording length to be an integral multiple of "100 mm", recording is started from the same position in any page recording.

In this case, for example, the outer circumference of the feed roller 16 is "100 mm", and the guide roller 1
If the number of 2 and 15 is "60 mm", the total error period is "300 mm". In such a case, "60m
If you want to create a block with a length of "m",
It is not rational because a space of "m" must be provided.

In such a case, the feed roller 16
And the guide rollers 12 and 15 can be connected by a gear or a gear belt having a gear ratio of 2: 1. In this way, by coupling with the gear or the like, the guide rollers 12 and 15 can be made to make two rounds while the feed roller 16 makes one round, and the entire error period can be set to “100 mm”.

[0019]

As described above, according to the present invention, when creating a plurality of master plates, even if there is an error cycle that is unavoidable due to the mechanical tolerance of the recording paper feeding system, the respective master plate start positions are related. Since it can be set to a specific position of the error period, the overlay error of the printing plates due to them can be minimized.

[Brief description of drawings]

FIG. 1 is a configuration explanatory diagram of a block making device according to the present invention.

FIG. 2 is a schematic diagram for explaining an error cycle.

FIG. 3 is a schematic diagram showing a block making operation of the present invention.

[Explanation of symbols]

10: recording paper 13: thermal head 14: platen roller 16: feed roller 19: encoder 24: cue circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Kawata 503-10 Shinanomachi, Totsuka-ku, Yokohama, Kanagawa Prefecture Graphtec Co., Ltd.

Claims (2)

[Claims] 1. A recording paper holding unit for holding a series of recording papers,
A recording unit that draws a predetermined page image on the recording paper fed from the recording paper holding unit according to an image signal, a recording paper cutting unit that cuts the page image recorded by the recording unit for each page, and the recording unit described above. A recording paper transfer unit that transfers the paper at a predetermined speed and route from the recording paper holding unit to the cutting unit through the recording unit, and a plurality of page images to control each of these elements to form a block copy. In the block making device having a control means for making, the control means records a plurality of page images to be used as a master copy, and a periodicity storage means for storing beforehand the periodicity of the transfer of the recording paper transfer means. Recording position determining means for starting recording from the same position of the periodicity for any page image based on the contents stored in the periodicity storing means. Plate making apparatus that. 2. The plate-making apparatus according to claim 1, wherein the periodicity of the entire recording paper transport system is calculated from the periodicity of each element of the recording paper transport means, and the overall periodicity is specified. A block copy creating device characterized by storing a position in a periodic storage means.