JPS629967A - Multi-color printer - Google Patents

Abstract

PURPOSE:To diminish the generation of shear in color printing by removal of the divergence of the relative position of a recording paper and a thermal head, by determining the timing of printing by detection of the reach of the drum on which the recording paper is wound to a fixed position. CONSTITUTION:A recording paper 5 is wound on the outer periphery of a drum 10 and an ink donor film (1DF)1 is transferred. At the point when a marker 15 is detected with a photo receiving element 14, 1DF 1 is stopped to be transferred. A detection piece 12 is detected with a sensor 13 by driving the drum 10 and the pulse of the step motor driving the drum 10 is counted with a sequencer 17. On the N-th pulse, the printing start end of recording paper 5 reaches a thermal head 4, the thermal head 4 being pressed onto the drum 10 and the transfer of data to the thermal head 4 is indicated to a data generator 18. The sequencer 17 sends a stroboscopic signal to the thermal head 4 when time td has elapsed from the generation time point of detection signal in the sensor 13. 1DF 1 is heated and the transfer of the first color by cyan color is carried out onto the recording paper 5. In the same way,the transfer to the second, third and fourth colors are repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multicolor printer that eliminates relative positional deviation between recording paper and a thermal head', thereby preventing color misregistration.

[Conventional technology]

As a conventional color thermal printer, there is one shown in FIG. 6, for example. This is an ink donor film (ID
F) I, a 1rlF roll 2 around which a predetermined length of ■DPI is wound, and a take-up roll 3 that winds up used IDPI;
I r) ID installed in the middle of the conveyance path of F roll 2
A thermal head 4 that contacts the non-ink surface of the E roll 2 and has a heating resistor driven according to image information;
The recording paper 5 is composed of a platen 6 which presses a recording paper 5 on which printing is to be performed against the thermal head 4 when the recording paper 5 is overlapped with the ink surface of the head 4 and the head 4 is reciprocated.

In the above configuration, the leading end surface of the recording paper 5 is aligned with the ink joint part of the TDFI, the recording paper is overlapped with the I D F ], and the recording paper is generally fed stepwise in the direction of the arrow. The generation of f (pH) drives the resistor, heats the ink of I 11F 1, and transfers it to the recording paper 5. For example, when performing color printing by subtracting and mixing yellow, magenta, and cyan inks, the yellow After recording (transferring) one sheet of recording paper while conveying the recording paper 5 in six directions without overlapping the ink surface, the recording paper 5 is conveyed in the direction B and returned 17, and its leading edge is The surface is aligned with the boundary surface between yellow and magenta. Next, the magenta ink surface of TI')Fl and the recording paper 5 are conveyed while being superimposed, and recording with magenta ink is performed. After the magenta ink recording is completed, the recording paper 5 is returned to the B direction again, aligned with the cyan ink surface, and the third color is recorded, thereby making it possible to obtain a color print by subtractive color mixing. . In the thermal navel 1', a voltage of more than ten volts is applied to the heating resistor in response to a recording signal, and no voltage is applied when there is no recording signal.

[Problem that the invention seeks to solve]

However, in conventional multi-color printers, the reciprocating motion of the recording paper is performed by rotating I-live rollers and pinch rollers, so slippage occurs between these rolls and the recording paper, causing the paper to move back and forth for each color. There is a problem that the printing position is shifted, resulting in color misalignment.

Means and operation for solving problem C] The present invention has been made in view of the above, and in order to eliminate the color shift caused by the relative movement of the recording paper and the thermal head, the recording paper is To provide a multi-color printer which detects when a wrapped drum has reached a fixed position and determines printing timing based on this detection.

〔Example〕

The multicolor printer according to the present invention will be described in detail below.

1 and 2 show positional embodiments of the present invention, and the same reference numerals are used for the same parts as in FIG. 4, so redundant explanation will be omitted. A drum 10 having a diameter that allows wrapping, a gripper 1 provided at one horizontal position on the circumferential surface of the drum 10 to fix the edge of the recording paper 5, and a gripper 1 on the side surface of the drum 10.
Detection piece 1 using a magnet or metal material provided in several places
2, and a drum J, 1 provided near the thermal head 4.
A drum position sensor 13 detects the detection piece 12 that arrives with the rotation of 0, and a marker 15 for identifying the leading color formed near the leading color (cyan in FIG. 1) on the side surface of 1r) Fl. a light-receiving element I4 that emits light to the light-receiving element 14 via Ir)Fl, and a sensor 13.
and a sequencer 17 that provides a strobe signal to the thermal head 4 based on the output signal from the light receiving element 4.
and a data generator 18 which receives a data transfer command from the sequencer 17 and outputs data to be printed to the thermal head 4.

The surface of the drum 10 is formed using rubber with a specific hardness, and is configured to contact the thermal head 4 with appropriate pressure.

In the above configuration, when the recording paper 5 is mounted on the drum 10, the thermal head 4 is separated from the surface of the drum 10 by a drive mechanism (not shown). Therefore, the recording paper 5 is wound around the outer periphery of the drum 10, and its leading edge is fixed by the gripper 11. Then, IDFI is transported, and when the marker 15 is detected by the light receiving element 14, the transport of Ir)Fl is stopped. Next, by rotating the drum 10, the detection piece 12 is detected by the sensor 13. Upon this detection, the sequencer 17
Count the pulses of the step motor (not shown) that is driving the motor. This pulse corresponds to one print rask, and when the number of pulses is N [1, the print start edge of the recording paper 5 reaches the thermal heel i''4. At the Nth time, the thermal head 4 is brought into pressure contact with the drum 10, and the data generator 11 is commanded to transfer data to the thermal head 4 as shown in FIG. :J: When time t4 has elapsed since the detection signal was generated in the sensor 13, a strobe signal is sent to the thermal navel 14 as shown in Fig. 3.As a result, the IDPI is heated in accordance with the recording signal, and the recording paper A first color transfer is performed using 5 Hessian colors.

Even after the transfer of the first color is completed, the transport of TnFI continues, and the ram 10 continues to rotate (the thermal head 4 also continues to be in pressure contact). As the drum 10 makes one revolution and the detection piece 12 reaches the sensor 13 again, the number of pulses is counted, and the data in response to magenta is sent from the data generator 18 to the thermal head 4. given to.

At this time, the magenta side of the IDPI has reached the thermal head 4, and magenta is transferred onto the recording paper 5. Thereafter, the transfer for the third color (yellow) and the fourth color (blank) is repeated seven times as described above, and a multicolor print is performed.

In the above embodiment, the drum position is detected by a combination of the detection piece 12 and the magnetic sensor 13, but a combination of an optical sensor and a coat may also be used.

An example of this is shown in Figure 4, in which a cord 2o is attached to the side of the drum 1o in the same center as the drum 1o, at least one cord 21 is marked around it, and the cord An optical sensor (reflection type) 22 is provided at a passing position of 21.

The code wheel 20 rotates together with the drum, and the coat 2
Each time one passes through the detection surface of the optical sensor 22, the sensor 22 outputs an electrical signal. The output of this optical sensor 22 can be used in place of the output of the sensor 13 shown in FIG.

FIG. 5 shows an example in which the detection accuracy of the configuration shown in FIG. 4 has been improved by one, in which a two-1' wheel 23 in which the diameter of the code wheel 20 is larger than the diameter of the drum 10 is used. That is, with respect to the radius p1 of the drum 10, the diameter p2 of the two-wheel 23 is a2>g.

It is set to . By doing this, the rotation of the drum 10 causes the drum itself to move 6 m1, while the peripheral edge of the code wheel 23 moves 6 m2, and the relationship is 6 m2>8 In. As a result, 6
Since the movement rate of m2 is larger than that of 6m1, position detection can be performed with higher sensitivity (i7.) than in the case of FIG. 4 in which the cord 21 is provided around the column 10.

Although a reflection type optical sensor is used in this embodiment, a transmission hole may also be used. In this case, the cord needs to be replaced with a slit or the like.

〔Effect of the invention〕

(Explained above) According to the present invention. 1, then the recording paper is installed.] Since the start of printing is determined by determining the arrival of the leading edge of the recording paper to the thermal head based on the rotational position of It is possible to print in the same position and eliminate color shift. Further, when position detection is performed using a code, the accuracy of position detection can be improved by making the code wheel larger than the tram diameter.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
FIG. 3 is a time chart showing the operation of the embodiment of the present invention, FIG. 4 is a perspective view showing another example of the position detection sensor, and FIG. 5 is a position detection sensor. FIG. 6 is a perspective view showing still another example of a sensor, and FIG. 6 is a schematic configuration diagram showing an example of a conventional multicolor printer. Explanation of symbols 1 ---- ■ DF, 4 ------- Thermal Hen 1 C 5 ---- Recording paper, 10 -------
Drum, 12----1 detection piece, 13--1---
-Sensor, 14-111--Photodetector, 15----
1- marker, 16- light emitting element, 17----
Sequencer, 18 ---- Data generator, 20.23 ---- Call point, 21 ----
-Code, 22----Optical sensor 0 patent
Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Shin Matsuhara 2 Same as Seiji Muraki Same as Hirata, Tadashi `` Same as Same as Atsushi Kamijima -=・3rd
Figure 4 Figure 5

Claims (3)

[Claims] (1) An ink donor film (in which heat-melt inks of different colors are repeatedly applied to the film surface over a predetermined length)
A multicolor printer that heats an IDF (IDF) according to a recording signal and transfers the heated portion to recording paper wound around a drum, comprising: a detection means for detecting that the drum has reached a fixed position; and the detection means. The multifunction printer is characterized by further comprising a control unit that determines the timing at which the leading edge of the recording paper reaches the printing surface of the thermal head based on detection by the thermal head, and determines the timing to start supplying print data and strobe signals to the thermal head. Color color printer. (2) The detection means includes a detection piece provided around the side surface of the drum and a sensor that electrically detects passage of the detection piece. Multicolor printer as described in section. (3) The detection means includes a code wheel having a diameter larger than the diameter of the drum, having at least one code provided around its periphery and being attached to the rotating shaft of the drum;
2. The multicolor printer according to claim 1, further comprising an optical sensor for optically detecting a code passing through a set position in response to rotation of the code wheel.