JP3640443B2 - Video printer feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper feeder for a video printer, and more particularly to a paper feeder for a video printer that records an image using a recording material wound up in a roll shape.
[0002]
[Prior art]
Various recording methods are employed for video printers, but thermal printers, ink jet printers, and the like are becoming widespread due to the low cost of devices and running costs. When a full color image is to be printed at a high speed in such a video printer, for example, in a thermal printer, three thermal heads are arranged in the passage region of the recording material, and the recording material is moved from the upstream side to the downstream side. A one-pass, three-head type color thermal printer is known in which a yellow image, a magenta image, and a cyan image are sequentially recorded by each thermal head during circulation to form a full color image (for example, Japanese Patent Laid-Open No. 5-201043). No. 6 and Japanese Patent Publication No. 6-96338).
[0003]
[Problems to be solved by the invention]
In such a one-pass, three-head type color thermal printer, a roll-like recording material obtained by winding a strip-like recording material in a roll form is used as a color thermosensitive recording material. Therefore, when the roll-shaped recording material is rotated in the direction opposite to the winding direction and the strip-shaped recording material is fed to the print unit, the roll diameter of the roll-shaped recording material is reduced by consuming the recording material. The paper feed amount fluctuates due to gradually decreasing, and slack and pulling occur between the print unit. When such sagging or pulling occurs, it acts as a load fluctuation during printing by the thermal head, for example, in the next printing section, and registration errors (color misregistration), density unevenness, color unevenness and the like occur.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a video printer paper feeding device that can feed a strip-shaped recording material from a roll-shaped recording material without being affected by the roll-shaped recording material.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a motor for rotating a roll-shaped recording material in the recording material feeding direction, a mark sensor for detecting a positioning mark near the outermost peripheral surface of the roll-shaped recording material, and the mark sensor. And a controller for controlling the rotation of the motor so as to be the same as the recording material feed speed on the print stage side based on the feed speed equivalent value. Is. The mark sensor is attached to the guide arm, the guide arm is swingably attached so as to be in contact with the outermost peripheral surface of the roll-shaped recording material, and the distance between the outermost peripheral surface of the recording material and the mark sensor is kept constant on the guide arm. It is preferable to provide a guide member. The motor is preferably composed of a pulse motor. In this case, the controller includes a mark detection interval measurement circuit for measuring a mark detection interval time equivalent value based on the mark detection signal, and the mark detection interval measurement circuit. It is preferable to include a pulse rate determining unit that determines the pulse rate of the pulse motor based on the mark detection interval time equivalent value, and a pulse generator that generates a driving pulse of the pulse motor based on the pulse rate from the pulse rate determining unit.
[0006]
Further, it is preferable to provide means for forming a slack in the recording material between the print stage.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows a linear moving color thermal printer. Three platen rollers 11, 12, and 13 are rotatably arranged at appropriate intervals along the passage region (pass) of the color thermosensitive recording material 10. A yellow thermal head 14, a magenta thermal head 15, and a cyan thermal head 16 are arranged to face each of the platen rollers 11 to 13, so that the yellow print stage 17 and the magenta print stage 18 are arranged along the path. , A cyan print stage 19 is formed. The platen rollers 11 to 13 are selectively set at a crimping position where the roller shift mechanism 20 is crimped to the heating element arrays 14a to 16a of the thermal heads 14 to 16 and at a separate retracted position.
[0008]
The print stages 17 to 19 are provided with recording material transport units 21, 22, and 23 and recording units 25, 26, and 27 that drive the thermal heads 14 to 16 to record color images on the recording material 10. These are controlled by the system controller 28 (see FIG. 1). In each of the transport units 21 to 23, an auxiliary roller pair 30, a leading end sensor 31, and a mark sensor 32 are sequentially arranged on the upstream side in the recording material feeding direction with respect to each of the thermal heads 14 to 16. On the other hand, a conveying roller pair 33 is arranged on the downstream side. The lower roller of each roller pair 30, 33 is a drive roller 30 a, 33 a and is rotated by a pulse motor 34. The upper rollers 30b and 33b of each roller pair 30 and 33 are selectively set between the nip position and the nip release position by the roller shift mechanisms 35 and 36. The nip pressure of each auxiliary roller pair 30 is set to be smaller than the nip pressure of the transport roller pair 33 so that the transport by the transport roller pair 33 is mainly performed. Further, a yellow fixing device 37 is disposed on the downstream side of the yellow print stage 17, and a magenta fixing device 38 is disposed on the downstream side of the magenta print stage 18.
[0009]
A paper feeding device 40 of the present invention is disposed upstream of the yellow print stage 17 in the recording material feeding direction. The paper feeding device 40 includes a holding shaft 42 that holds a roll-shaped recording material 41, a paper feeding motor 43 that rotationally drives the holding shaft 42, and a motor control unit 45. A roll-shaped recording material 41 is fitted and fixed to the holding shaft 42, whereby the roll-shaped recording material 41 is integrated with the holding shaft 42.
[0010]
As shown in FIG. 1, the motor control unit 45 controls the rotation of the paper feed motor 43 formed of a pulse motor based on the mark detection signal from the mark sensor 50 so that the feeding speed of the recording material 10 is controlled by the yellow transport unit 21. Set to the same transport speed. The mark sensor 50 is attached to the tip of the guide arm 51. The guide arm 51 is provided so as to be swingable via an attachment shaft 52. A guide roller 53 is attached to the tip of the guide arm 51. The guide roller 53 rotates in contact with the outermost peripheral surface of the roll-shaped recording material 41, so that even if the winding diameter of the roll-shaped recording material 41 is reduced, the mark sensor 50 and the roll-shaped recording material are rotated. The distance from the outermost peripheral surface of the material 41 is always constant. Further, the guide arm 51 is biased by a coil spring 54 so that the guide roller 53 comes into light contact with the outer peripheral surface of the roll-shaped recording material 41.
[0011]
The mark sensor 50 is composed of a reflection type sensor having a light projecting part and a light receiving part. As shown in FIG. 3, the mark sensor 50 has positioning marks 56 formed on the recording material 10 at a predetermined pitch L1. To detect. The positioning mark 56 is recorded by printing on the surface opposite to the surface on which the heat-sensitive recording layer of the color heat-sensitive recording material 10 is formed. The positioning marks 56 are formed at a ratio of one for each recording area PA corresponding to the recording area PA, and the pitch thereof is L1. Note that a large number of positioning marks may be recorded in one recording area by reducing the pitch so as to correspond to the size change of the recording area PA. In this case, recording is performed according to the number of detected positioning marks. The area PA is specified.
[0012]
As shown in FIG. 1, the mark sensor 50 is driven by a sensor drive detection circuit 60, and the LED for light projection has a fixed period (period that is shorter than the length L <b> 2 of the positioning mark 56 (see FIG. 3)). Driven by. The mark detection signal from the light receiving unit is amplified by the sensor drive detection circuit 60 and then sent to the paper feed motor control circuit 61. The paper feed motor control circuit 61 includes a counter 62 and a pulse rate conversion circuit 63. The counter 62 receives a clock pulse from the reference clock generation circuit 64, latches the clock pulse count value based on the mark detection signal, and then resets to count the number of clock pulses corresponding to the mark detection interval time. To do. The count value of the clock pulse is sent to a pulse rate conversion circuit 63 configured from a look-up table memory (LUT), and a pulse rate corresponding to the count value is obtained here. The relationship between the count value and the pulse rate is obtained in advance by experiments or the like, and this is written into the LUT of the pulse rate conversion circuit 63 by the system controller 28. In the memory 65 of the system controller 28, the relationship between the count value and the pulse rate is written in advance.
[0013]
As for the relationship between the count value and the pulse rate, if the count value increases more than the reference number of pulses (the number of pulses that are the same as the transport speed on the print side) (the sending speed decreases), the pulse rate is increased and the feed rate is increased. The rotational speed of the paper motor 43 is increased so that the recording material feed speed on the print stage 17 side can be made the same. When the count value decreases below the reference pulse number (the sending speed increases), the pulse rate is lowered to lower the rotation speed of the paper feed motor 43. Similarly, the recording material feed on the paper feed side is reduced. The speed and the feed speed on the print stage 17 side can be made the same.
[0014]
The pulse rate from the pulse rate conversion circuit 63 is sent to the programmable pulse generator 66, where the pulse rate of the drive pulse of the paper feed motor 43 is changed. The drive pulse signal whose pulse rate has been changed by the programmable pulse generator 66 is sent to the driver 71. The driver 71 rotates the paper feed motor 43 based on this drive pulse signal. FIG. 4 is a flowchart showing a paper feed control processing procedure in the system controller 28.
[0015]
The strip-shaped recording material 10 sent out by the paper supply device 40 is sent to the yellow print stage 17 through the paper supply roller pair 70. The paper feed roller pair 70 is rotationally driven by a pulse motor 34 that rotates the transport roller pair 33 on the print stage 17 side, and transports the recording material 10 at the same transport speed as the print stage 17. Similarly to the other roller pairs 30 and 33, the paper feed roller pair 70 is composed of a driving roller 70a and an upper roller 70b. The upper roller 70b is placed between a nip position and a retracted position by a roller shift mechanism (not shown). It is supposed to change in. When the recording material 10 passes through the leading edge, the upper roller 70b is set to the retracted position, and otherwise, the upper roller 70b is set to the nip position. Further, a clutch 72 is disposed between the pair of paper feed rollers 70 and the pulse motor 34, and this clutch 72 transmits the drive of the pulse motor 34 only when the leading edge of the recording material 10 is sent to the yellow print stage 17. In other cases, the paper feed roller pair 70 is set in a free state. The paper feed roller pair 70 is rotated by the pulse motor 34 on the print stage 17 side. Alternatively, the paper feed roller pair 70 may be rotated by using the paper feed motor 43. Also in this case, a crack is provided between the paper feed motor 43 and the paper feed roller pair 70, and the rotation of the paper feed motor 43 is transmitted only when the leading edge of the recording material 10 is sent to the yellow print stage 17. Sometimes, the paper feed roller pair 70 is set to a free state.
[0016]
Further, a cutter 71 is disposed in the paper feeding device 40, and when the cutter 71 reaches a predetermined number of prints, the belt-shaped recording material 10 is cut at a predetermined position with reference to the positioning mark 56. Whether or not the predetermined number of prints has been reached is determined by counting the mark detection signal of the mark sensor 50. Then, when the predetermined number of sheets set in advance is obtained as a result of this determination, the recording material is based on the positioning mark 56 by the cutter 71 on the paper feeding device 40 side based on the detection signal of the positioning mark 56 that has reached this number. 10 is cut. In this case, since the single mark sensor 50 can be used for detecting the cutting position and detecting uneven feeding, the configuration is further simplified.
[0017]
In each of the print stages 17, 18, and 19, the nips of the roller pairs 70, 30, and 33 are released during feeding, and the pressure bonding of the platen rollers 11 to 13 is released. Then, the leading edge of the recording material 10 is tracked based on the leading edge detection signal from the leading edge sensor 31, and the leading edge of the recording material 10 is brought into a nip state as the leading edge of the recording material 10 sequentially passes through the roller pairs 70, 30, 33. Further, the head press-bonding start position and the recording start position are specified based on the mark detection signal from the mark sensor 32, and each color is recorded one line at each of the print stages 17-19. After the yellow recording, the yellow heat-sensitive recording layer is optically fixed by the yellow fixing device 37. Further, after magenta recording, the magenta thermosensitive recording layer is optically fixed by the magenta fixing unit 38. In this way, yellow, magenta, and cyan thermal recording layers are recorded in the same recording area, and a full-color image is obtained. This full-color image is cut off for each frame by a cutter (not shown) at the margin between the images based on the detection signal of the positioning mark 56. Note that the thermal heads 14 to 16 are pressed against the recording material 10 when the first image is recorded. When a plurality of images are recorded, the thermal heads 14 to 16 are pressed onto the recording material 10. It is in the state. Then, after the recording of the last image is completed, the pressure bonding of the thermal heads 14 to 16 is released, and the rear end of the recording material 10 smoothly passes through the thermal heads 14 to 16.
[0018]
As shown by a two-dot chain line in FIG. 2, slacks 80 and 81 may be formed in the color thermal recording material 10 between the thermal heads 14 to 16. These slacks 80 and 81 prevent the transfer load fluctuation caused by the change in the behavior of the thermal head in one print stage from being transmitted to the other print stage. Furthermore, a slack 82 may be formed in the recording material 10 between the paper feeding device 40 and the yellow print stage 17 or between the cyan print stage and the paper discharge mechanism to serve as a buffer means for absorbing load fluctuations. For example, the slack 82 between the paper feeding device 40 and the yellow print stage 17 is formed by providing a difference between the paper feeding speed and the recording material conveyance speed in the yellow print stage 17. By doing so, the transfer load fluctuation in the sheet feeding device 40 is absorbed by the slack and is not transmitted to the yellow print stage 17. The amount of sag of the sag 82 is determined by detecting the sag amount fluctuation by obtaining the recording material conveyance speed between the yellow print stage 17 and the paper feeding device 40 based on the pulse rate and the like. Adjust the paper speed. Further, the amount of sag may be detected using a micro displacement meter, and in this case as well, the amount of sag is kept constant by adjusting the paper feed speed.
[0019]
Further, as shown in FIG. 5, the paper feed roller pair 85 may be rotated by a paper feed motor 86 to feed paper. In this case, paper is fed based on the mark detection signal of the mark sensor 87 using the motor control unit 45 shown in FIG. Then, by providing a difference between the paper feed speed and the recording material feed speed in the yellow print stage 17, a slack 88 is formed, and this slack is maintained within a certain range. In addition, the same code | symbol is attached | subjected to the same component as what is shown in FIG. Reference numeral 89 denotes a guide roller.
[0020]
Further, as shown in FIG. 6, the paper feed motor 90 may rotate the paper feed roller pair 91 and the receiving roller 92 to feed paper. Also in this case, paper is fed based on the mark detection signal of the mark sensor 93 using the motor control unit 45 shown in FIG. Further, a slack 94 is formed between the yellow print stage 17 in the same manner as described above. In addition, the same code | symbol is attached | subjected to the same component as what is shown in FIG.
[0021]
In the above-described embodiment, the motor control unit 45 is configured by hardware using the counter 62, the pulse rate conversion circuit 63, the programmable pulse generator 66, and the like, but may be implemented by software. Further, although the pulse rate conversion circuit 63 is configured by an LUT, other than this, an arithmetic expression may be obtained in advance, and the pulse rate may be obtained by computation. In the above embodiment, the mark sensor 50 is always arranged at a fixed position from the outer peripheral surface of the roll-shaped recording material 41 using the guide arm 51. In addition to this, the radial direction of the roll-shaped recording material 41 is also used. It is also possible to provide a slider that can be shifted with a mark sensor.
[0022]
In the above embodiment, the positioning mark 56 is recorded by printing on the surface of the color thermal recording material 10 opposite to the thermal recording layer forming side, but the positioning mark is formed from a small hole or notch. May be.
[0023]
In the above embodiment, the color thermal printer has been described. Although not shown, the present invention may be applied to a sublimation thermal transfer printer using yellow, magenta, and cyan color ink ribbons. Good. In this case, a color ink ribbon is interposed between each heating element array of the thermal head and the recording material, and the ink from each ink ribbon is thermally transferred to the recording material. Moreover, it is good also as a heat melting type instead of a sublimation type. Furthermore, the present invention may be implemented for a monochrome thermal printer or a color or monochrome inkjet printer instead of the color thermal printer.
[0024]
【The invention's effect】
In the present invention, the roll-shaped recording material is rotated by a motor in the recording material feeding direction, the positioning mark is detected by the mark sensor near the outermost peripheral surface of the roll-shaped recording material, and the feeding speed equivalent value is calculated based on this mark detection signal. Since the rotation of the motor is controlled to be the same as the recording material feed speed on the print unit side based on this value corresponding to the feed speed, the strip-shaped recording material can be printed from the roll-shaped recording material with a simple configuration. It becomes possible to feed at the same speed as the department side. Therefore, the feeding speed of the recording material does not fluctuate due to the roll-down recording material. As a result, the conveyance load fluctuation due to the feeding speed fluctuation is not transmitted to the print stage, and the occurrence of color misregistration, density unevenness, color unevenness, and the like can be suppressed. In addition, since the roll-shaped recording material is rotated in the recording material feeding direction by the motor, efficient feeding can be performed even for a recording material having a large roll diameter, which is difficult to feed by only a pair of feeding rollers. .
[0025]
Also, the mark sensor is attached to the guide arm, the guide arm is swingably attached so as to be in contact with the outermost peripheral surface of the roll-shaped recording material, and the distance between the outermost peripheral surface of the recording material and the mark sensor is fixed to the guide arm. Since the holding guide member is provided, the mark formed on the recording material can be detected in a stable state at all times. In addition, since the mark detection interval measurement circuit detects the value corresponding to the mark detection interval time based on the mark detection signal to detect the change in the recording material feed speed on the paper feeding side, it can be easily used without using a pulse encoder or the like. Speed fluctuations can be detected with a simple configuration. In addition, the pulse rate determination unit obtains the pulse rate of the pulse motor based on the mark detection interval time equivalent value, and the pulse motor drive pulse is generated by the pulse generator based on the pulse rate from the pulse rate determination unit. Even when the winding diameter or thickness of the recording material is changed, it is possible to easily cope with the change of the recording material by determining the pulse rate so as to cope with the change.
[0027]
In addition, since a certain range of sag is formed in the recording material between the print stage and the sag, the sag absorbs the transfer load fluctuation and acts as a buffer, so that the transfer load fluctuation on the paper feed side is transmitted to the print stage side. Therefore, it is possible to suppress the occurrence of color misregistration, density unevenness, and the like due to conveyance load fluctuations.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a paper feeding device of a color thermal printer embodying the present invention.
FIG. 2 is a schematic view of the color thermal printer.
FIG. 3 is a plan view showing a positioning mark of a color thermosensitive recording material.
FIG. 4 is a flowchart showing a processing procedure in the system controller.
FIG. 5 is a schematic view showing a main part of another embodiment.
FIG. 6 is a schematic view showing a main part of another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Color thermal recording material 11-13 Platen rollers 14-16 Thermal heads 17-19 Print stage 21-23 Conveyance part 40 Paper feed apparatus 41 Roll-shaped recording material 43,86,90 Paper feed motor 50,87,93 Mark sensor 51 Guide arm 53 Guide roller 56 Positioning mark 70, 85, 91 Feed roller pair 71 Cutter 80-82, 88, 94 Slack

Claims (4)

In a paper feeder of a video printer that has a positioning mark formed at a constant pitch and draws the leading end from a roll-shaped recording material wound in a roll form and sends it to a print stage.
A motor for rotating the roll-shaped recording material in the recording material feeding direction;
A mark sensor for detecting the positioning mark near the outermost peripheral surface of the roll-shaped recording material;
A controller that detects the feed speed equivalent value based on the mark detection signal from the mark sensor and controls the rotation of the motor so as to be the same as the recording material feed speed on the print stage side based on the feed speed equivalent value. And a video printer paper feeding device. The paper feeder of the video printer according to claim 1,
The mark sensor is attached to a guide arm, the guide arm is swingably attached so as to contact the outermost peripheral surface of the roll-shaped recording material, and the distance between the outermost peripheral surface of the recording material and the mark sensor is fixed to the guide arm. A paper feeding device for a video printer, characterized in that a guide member is provided to maintain the thickness. The paper feeding device of the video printer according to claim 1 or 2,
A feeding device for a video printer, comprising means for forming a slack in a recording material between the printing stage and the printing stage. In the paper feeder of the video printer according to any one of claims 1 to 3,
The motor is composed of a pulse motor, and the controller uses a mark detection interval measurement circuit that measures a mark detection interval time equivalent value based on the mark detection signal, and a mark detection interval time equivalent value from the mark detection interval measurement circuit. A video printer paper feeding device comprising: a pulse rate determining unit that determines a pulse rate of a pulse motor based on the pulse rate; and a pulse generator that generates a driving pulse of the pulse motor based on the pulse rate from the pulse rate determining unit .

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