JPS6410980B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transfer-type thermal recording device, and in particular to a color recording device composed of a line thermal head, an ink donor film corresponding to the line thermal head, and a back roller. Multi-color transfer, which has transfer thermal recording sections for two or more colors, and each recording section transfers the image information of the respective color independently, and records a multicolor original by superimposing the transferred image information of each color. The present invention relates to a thermosensitive recording device.

[Prior art]

FIG. 1 is a schematic diagram conceptually showing an example of the configuration of a conventional multicolor transfer type thermal recording device. The device includes a line thermal head 10, a back roller 11, and a black ink donor film (hereinafter referred to as black IDF) 1.
2. A black transfer thermal recording section 100 consisting of a supply roller 13, a take-up roller 14, and a drive roller 15 of the black IDF 12, a line thermal head 20, a back roller 21, and a red ink donor film (hereinafter referred to as red IDF) 22.
A red transfer thermal recording section 2 consisting of a supply roller 23, a take-up roller 24, and a drive roller 25.
This is a two-color transfer type heat-sensitive recording device having 00.
The line thermal heads 10 and 20 are connected to a pressing mechanism (not shown), and are pressed against the back roller 11 and the back roller 21 via the black IDF 12 and the red IDF 22 at the start of recording.

At the same time, the black IDF12 and the red IDF
22 transport has also started and the black IDF12 and red
The IDF 22 is transported between the line thermal head 10 and the back roller 11 and between the line thermal head 20 and the back roller 21 of each recording section, and is sequentially wound up from the respective supply rollers 13 and 23 to the winding rollers 14 and 24. On the other hand, a recording paper P is supplied from a recording paper supply mechanism (not shown).
The black color of the black transfer section 100 starts to be conveyed.
It is supplied between the IDF 12 and the back crawler 11. Thereafter, the recording paper P is transported between the black IDF 12 and the back roller 11 in synchronization with and in close contact with the black IDF 12 that has been transported in advance as described above. At this time, the recording paper P is covered with the black IDF 1, which is melted at the required heat generation location of the thermal head 10, which is selectively driven according to the black image information of the predetermined original.
Ink No. 2 is transferred, and only black image information is recorded first. The recording paper P on which this black image information has been recorded is then transferred to the red IDF of the red recording section 200.
22 and the back roller 21, and is conveyed here as well in close contact with and in synchronization with the red IDF 22, which has been conveyed in advance like the black recording section 100.

At this time, the molten ink of the red IDF 22 is transferred, which is melted at a required heat generation location of the thermal head 20, which is selectively driven in accordance with the red image information of the predetermined original. Therefore, two-color image information is recorded on the recording paper P by combining the previously transferred black image information and the red image information, and then the paper is ejected to a paper ejection tray (not shown). In this way, a plurality of transfer heat-sensitive recording sections of different colors are arranged in series, and while the same recording paper is sequentially conveyed through the recording sections, transfer of different colors is performed independently, and a combination of these transfer inks is used. In order to maintain good recording quality in a multicolor transfer type thermal recording apparatus that records a multicolor document, it is particularly important to prevent the transfer position of the molten ink in each recording section from shifting. However, according to the above-mentioned conventional apparatus, the conveyance speed of the ink donor film of each recording section, which is involved in the conveyance of the recording paper, is affected by minute differences in diameter and dirt conditions in the manufacturing process of each drive roller, or the diameter of each IDF supply roller. This has the drawback that the conveyance amount of the recording paper differs between each recording section because it easily fluctuates due to the difference or recording density, etc., resulting in misalignment of the transfer position of each color ink, which significantly impairs the recording quality at this time. .

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks, and even when there is a difference in the conveyance amount of recording paper in each recording section due to the above-mentioned factors, this invention can be corrected, and the transfer position shift of each color ink can be corrected. It is an object of the present invention to provide a multicolor transfer type thermal recording device that can obtain recorded images of good quality.

[Structure of the invention]

Therefore, in the present invention, the back rollers of each recording section are rotated as the recording paper is transported, and the load on the back rollers is small, and the back rollers are transported in a state where slips with the recording paper can be ignored, so that the amount of transport of both of them is equal to each other. Focusing on this point, the rotation angle of the back crawler can be detected with an angular accuracy corresponding to 1/n of the reference sub-scanning amount 1/N [mm] of the recording paper, that is, 1/nN [mm]. and the recording paper with its standard scanning amount 1/N.
The apparatus is configured to include at least a recording sheet conveying means that can feed the recording sheet in steps of 1/nN (mm) when it is fed by [mm], and the recording paper is conveyed in steps of 1/nN [mm]. Calculate the recording paper feed amount for the corresponding recording section, and find out that the recording paper feed amount for the corresponding recording section is 1/nN [mm] larger than the standard feed amount or the feed amount for other recording sections when 1 is used as the reference. or when the number of recording sheets decreases, the recording sheet feeding amount during the next sub-scanning in the recording section is set to n-1/nN [mm] or n+1/nN [mm], respectively, by controlling the recording paper conveying means. The above objective is achieved by making the following corrections.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below based on the accompanying drawings. First, the multicolor transfer type thermal recording device of the present invention has a new structure as shown in FIG. 2a, for example, on the shafts of each of the cross rollers 11 and 21 of the black recording section 100 and the red recording section 200 of the conventional device shown in FIG. Cross crawler rotation angle detector 31, 32
It is configured by attaching. As the back crawler rotation angle detectors 31 and 32, well-known incremental shaft encoders can be used. This incremental shaft encoder is composed of a rotating plate 33 in which a transparent portion and an opaque portion are formed with a uniform pitch, and a light emitting element 34 and a light receiving element 36 that are arranged opposite to each other with the rotating plate 33 in between. The output of the light receiving element 36 when the light emitted from the light emitting element 34 passes through the rotary plate 33 and the slit plate 35 and is received by the light receiving element 36 when the back rollers 11 and 21 rotate as the back rollers 11 and 21 rotate. As a result, a pulse train as shown in FIG.

Therefore, in the present invention, the number of pulses is counted, the rotation angle of each of the back rollers 11 and 21 is detected from the counted value, and the rotation angle of the recording paper P that is conveyed in synchronization with the rotation of the back rollers 11 and 21 is determined based on the rotation angle. I am trying to calculate the feed amount. By the way, the back crawler rotation angle detector 3
1 and 32 need to have a resolution capable of detecting a rotation angle equal to or less than 1/n of the reference feed amount of the recording paper P in the sub-scanning direction of 1/N [mm] for the reasons mentioned above. . For simplicity, if the above constants N and n are set to N=8 and n=4, respectively, the reference sub-scanning amount of the recording paper is 1/8
[mm], that is, 125 [μm], so each of the back crawler rotation angle detectors 31 and 32 is
It must be possible to detect a rotation angle equivalent to a feed amount of 4, that is, 125/4 = 31.25 [μm]. Now, if the diameter of the cross rollers 11, 21 on which the respective cross roller rotation angle detectors 31, 32 are arranged is 25 mm (that is, if the circumference of the cross rollers 11, 21 is 25π [mm], then the following formula 31.25 ×10 ^-3 : 25π = θ: A device that can detect θ = 0.143° or less from 360°, that is, a device with a resolution of 2518 (= 360° / 0.143°) pulses/rotation or more, shall be used. Also, each of the above records shall be used. Part 10
The conveyance of the recording paper P at 0 and 200 is performed by conveyance friction with the black IDF 12 and the red IDF 22, which are conveyed by the rotation of drive rollers 15 and 25, respectively. Therefore, in the present invention, the driving circuit of each stepping motor that participates in the rotation of each of the drive rollers 15 and 25 is configured to move the recording paper P by the reference sub-scanning amount 125 by the above-described method.
When sending only [μm], 1/4 of that is 125/4 =
It is configured with a control function that allows for stepwise feeding in steps of 31.25 [μm].

Next, the state of the feeding amount correction control of the recording paper P in each of the recording sections will be explained using the black recording section 100 as an example. FIG. 3 is a block diagram showing an example of the structure of the main part of the drive control circuit of the multicolor transfer type thermal recording apparatus of the present invention, that is, the recording paper feed amount correction circuit for the black recording section. First, a predetermined control pulse is sent from the drive control section 40 to the drive roller drive circuit 41 in response to a recording start operation by the operator. In the drive roller drive circuit 41 to which the control pulse is input, the drive roller 1 of the black recording section 100
A driving pulse is sent to the stepping motor 150 for driving the black color IDF 12, and the stepping motor 150 is driven in the steps described above to rotate the drive roller 15, thereby starting the conveyance of the black IDF 12. As the black IDF 12 is conveyed, the bag roller 11 is also rotated.
The back crawler rotation angle detector 31 disposed on the rotary shaft 1 generates a predetermined pulse (see FIG. 2b) corresponding to the rotation, which is detected by a counter.
Added to C ₁ . Furthermore, with the start of conveyance of the black IDF 12 mentioned above, the conveyance of the recording paper P is also started, and the recording paper P is first supplied between the back roller 11 and the black IDF 12 of the black recording section 100.
From this point on, the counter _C1 starts counting the pulses applied from the rotation angle detector 31. Therefore, the subsequent count values of the counter _C1 can be considered to correspond to the conveyance amount of the recording paper P. The count value of the pulses by this counter _C1 is then calculated by the paper feed amount calculation circuit 4.
3 and is converted into the actual feed amount of the recording paper P in the black recording section 100 through a predetermined calculation, and the converted value is then added to the comparator 44. On the other hand, a control pulse applied from the drive control section 40 to the drive roller drive circuit 41 is applied to the counter _C0 , and counting starts at the same time as the counter _C1 starts counting. and this counter C ₀
The count value is then added to the paper feed amount calculation circuit 42 and subjected to a predetermined calculation to determine whether the recording paper P should be fed to the black recording section 100 under the control of the drive roller drive circuit 41 to which the control pulse is input. It is converted into a standard (ideal) feed amount, and the converted value is also added to the comparator 44. Here, the comparator 44 is connected to each of the paper feed amount calculation circuits 42 and 43.
The standard feed amount in the black recording section 100 of the recording paper P detected by the method is compared with the actual feed amount, and the actual feed amount is determined as the standard of the recording paper P as described above. Sub-scanning amount 125 [μ
A corresponding control signal is sent to the drive roller driving circuit 41 depending on whether the amount is larger or smaller by 1/4 of 31.25 μm or 31.25 μm. If the actual feed amount is 31.25 μm greater than the reference feed amount, the comparator 44 sends a feed amount reduction signal to the drive roller drive circuit 41, for example. This feed amount reduction signal causes the drive roller drive circuit 41 to drive the stepping motor 1.
The number of driving pulses to be applied to 50 is reduced from the normal number by an appropriate number, and the feed amount of the recording paper P during the next sub-scanning is 1/4 line less than the standard feed amount of 125 [μm].
It is conveyed so that it becomes 93.75 (=125-31.25) [μm]. Contrary to the above, when the actual feed amount is 31.25 [μm] less than the reference feed amount, the comparator 44 sends out, for example, a feed amount increase signal.

In response to this feed amount increase signal, the drive roller driving circuit 41 increases the appropriate number of drive pulses to be applied to the stepping motor 150, and when the recording paper P is scanned in the next sub-scan, the reference feed amount is 125 [μ].
156.25 (=125+31.25) which is 1/4 line more than [m]
[μm] is transported. At this time, if printing is performed by sending the 156.25 [μm] at once, a white gap of 31.25 [μm] will occur between the print image information of the previous line, so the feed amount of 156.25 [μm] will be divided into two. However, the above-mentioned inconvenience can be solved by scanning the image twice and printing the same image information each time. By performing such correction of the feed amount of the recording paper P, the feed amount of the recording paper P in the black recording section 100 can always be made the same as the reference feed amount. Further, the recording paper feed amount correction control means as described above is also configured for the red recording section 200, and the feeding amount of the recording paper P calculated from the detected value of the back crawler rotation angle detector 32 of the red recording section 200 is Correction control similar to the above is performed. As a result, the feed amount of the recording paper P in each recording section can always be made to match the reference feed amount, and it is possible to reduce the positional deviation of the transfer ink due to the difference in the recording paper feed amount between each recording section, which has been a problem in the past. It can greatly contribute to improving printing quality.

Incidentally, in the above-mentioned embodiment, a correction method was described in which the feeding amount of the recording paper P in each recording section is corrected to the standard feeding amount, thereby matching the feeding amount of the recording paper between the respective recording sections. Calculate the feed amount for each recording section, compare each feed amount with the feed amount for one recording section as a reference, and calculate the relative difference (recording paper standard sub-scanning amount 1/N
The same effect as described above can be expected by a method of correcting the recording paper feed amount of each recording section to compensate for the difference when 1/n of [mm], that is, 1/nN [mm]) is detected. Further, in this embodiment, only the recording paper correction method for a two-color transfer type thermal recording apparatus has been described, but it goes without saying that the present invention can also be applied to a multicolor transfer type thermal recording apparatus using two or more colors.

〔Effect of the invention〕

As explained above, according to the multicolor transfer type thermal recording apparatus of the present invention, the recording paper feed amount of each recording section is detected from the rotation angle of the back roller of each recording section, and the recording paper feed amount of the corresponding recording section and the reference feed are detected. By comparing the amount of feed or the feed amount when using 1 of each recording section as a reference, and if a specific difference occurs between these, the feed amount is corrected within a range that does not impede the recording quality. Since the feeding amount of each recording section is made to be the same, the misalignment of the transfer ink can be reduced regardless of the difference in the diameter of each roller of each recording section, the dirt condition of the roller surface, the printing density, etc., and it is always stable. It has the excellent effect of being able to obtain high-quality printed images.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of the configuration of a conventional multicolor transfer type thermal recording device, and FIGS. 2a and 2b are schematic diagrams of a back crawler rotation angle detector installed in the device of the present invention and its back crawler rotation angle detection. FIG. 3 is a block diagram showing the main part of the control circuit of the multicolor transfer type thermal recording apparatus according to the present invention. 31, 32...Bath crawler rotation angle detector, 3
3... Rotating plate, 34... Light emitting element, 35... Slit plate, 36... Light receiving element, 40... Drive control unit, 41... Drive roller drive circuit, 42, 4
3...Paper feed amount calculation circuit, 44...Comparator.

Claims (1)

[Claims] 1. An ordinary recording paper and an ink donor film coated with heat-melting or heat-sublimable ink are superimposed, and they are pressed against a heat-sensitive recording head using a back roller, and image information is transferred from the heat-sensitive recording head. In a multi-color transfer type thermal recording device, which is equipped with a recording section for at least two colors that melts ink and performs color transfer recording on the recording paper using thermal energy selectively supplied according to the selected color, the recording paper is scanned by a sub-scanning amount of 1. /N
A recording paper transport means that transports the recording paper step by step in steps of 1/nN (n≧1; integer) [mm] when scanning by [mm]; A back crawler rotation angle detector detects the rotation angle of the back crawler with a rotation angle accuracy corresponding to nN [mm], and calculates the feed amount of the recording paper from the detection value of the back crawler rotation angle detector, and the recording section If the recording paper feed amount increases by 1/nN [mm] compared to the preset standard feed amount or the feed amount based on 1 for each recording section, the The recording paper conveying means is driven so that the feeding amount for the next scanning of the recording paper is n-1/nN [mm], and if it decreases by 1/nN [mm], it becomes n+1/nN [mm]. A multicolor transfer type thermal recording device characterized by comprising a control means for controlling the temperature.