JPH06278335A - Ink sheet feed device - Google Patents

Abstract

PURPOSE:To provide an ink sheet feed device capable of always feeding an ink sheet at a constant speed, reducing the number of parts and smoothly performing the replacing work of the ink sheet. CONSTITUTION:In a thermal line printer having a speed difference printing mechanism, an ink sheet taking-up roll 3 taking up the ink sheet 1 after the completion of printing, an ink sheet supply roll 4 sending out an unused ink sheet, a mechanism 20 for driving the ink sheet taking-up roll and a lock mechanism for suppressing the rotation of the ink sheet supply roll or making the same free are provided. The ink sheet feed guide 7 positioned between the ink sheet supply roll and a printing position and made possible to advance and retreat in the direction crossing the ink sheet, the drive means of the ink sheet feed guide and a control part are provided and the control part controls a drive means so as to move the ink sheet feed guide in the above mentioned crossing direction at a predetermined speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an ink sheet conveying mechanism in a recording apparatus using a thermal transfer recording process for printing and forming an image on a recording medium using an ink sheet.

[0002]

2. Description of the Related Art A thermal line printer for recording an image by thermally transferring ink on an ink sheet onto a recording medium using a thermal head is a color printer,
Conventionally known as a recording device in a color copying machine, a color facsimile, etc., this recording device records an image by melting or sublimating ink on an ink sheet by selective heat generation of a heating element of a thermal head. It is a thing. In such a melting type or sublimation type thermal line printer, the conveyance speed Vi of the ink sheet at the time of printing is 1 / n (where n is the conveyance speed Vp of the image receiving paper).
It is noted that the speed difference printing mechanism set to> 1) is effective in reducing the running cost by reducing the length of ink sheet used and in increasing the number of printed sheets per roll of ink sheet. Has reached the end.

In this type of printing mechanism, it is important to control the speed difference between the ink sheet and the image receiving paper to be constant, and the speed difference, that is, the fluctuation of the value of n, causes the fluctuation of the image density. appear. As a method for preventing such a change in speed difference, Japanese Patent Laid-Open No. 63-165169 discloses that two capstans are provided for ink sheet conveyance and image receiving paper conveyance, and the ink sheet is used as an image receiving paper. A configuration for carrying at a speed of 1 / n is disclosed. This transport mechanism is provided with a capstan roller and a pinch roller separately from the image receiving sheet transport means, and controls the speed on the upstream delivery side.However, in the speed difference printing mechanism, the tension applied to the ink sheet is Since it becomes large, it is necessary to process the surface of the capstan roller to improve the grip force, or to secure a large wrap angle of the ink sheet around the capstan roller. However, the former method has a problem that the ink sheet before use is more likely to be scratched, and the latter method has a problem that the conveyance path of the ink sheet is complicated.

Next, in Japanese Unexamined Patent Publication No. 2-86479, the diameter of the ink sheet take-up roll, the used length of the ink sheet, or the rotation amount of the ink sheet supply roll is detected, and driving is performed according to the detection result. A configuration is disclosed in which the conveyance ratio of the ink sheet is kept substantially constant by adjusting the drive amount of the means. This publication proposes various feedback methods for driving the ink sheet take-up roll to convey the ink sheet and eliminating speed changes due to changes in the winding diameter. However, each method requires a means for detecting the speed and the like and a means for feeding back the detection result to the conveying speed, so that the device cannot be complicated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and the speed at which the length of the ink sheet consumed for printing per image receiving paper is 1 / n of the printing length on the image receiving paper. In the differential printing mechanism, the ink sheet can be always conveyed at a constant speed without complicating the configuration and without being affected by the fluctuation of the winding diameter of the ink sheet roll, and the It is an object of the present invention to provide an ink sheet transporting device that can be shared with a driving source for transporting, achieve a reduction in the number of parts, and can smoothly perform an ink sheet replacement operation.

[0006]

In order to achieve the above object, the present invention provides a speed at which the ink sheet conveying speed Vi is printed as Vi = Vp / n (where n> 1) with respect to the image receiving sheet conveying speed Vp. In a thermal line printer having a differential printing mechanism, an ink sheet take-up roll that winds up an ink sheet that has finished printing, an ink sheet supply roll that sends out an unused ink sheet, and the ink sheet take-up roll are driven. Mechanism for locking the ink sheet supply roll, a lock mechanism for suppressing or freeing the rotation of the ink sheet supply roll, and a lock mechanism arranged between the ink sheet supply roll and the printing position and capable of advancing and retracting in a direction intersecting with the ink sheet. And an ink sheet transport guide, a drive unit for driving the ink sheet transport guide, and a controller. The controller controls the ink sheet transport guide at a predetermined speed. By controlling the driving means so that the ink sheet is moved in the difference direction, constant speed driving of the ink sheet is realized, and the driving means of the ink sheet conveying guide is mechanically connected to the image receiving paper conveying means. The drive means for the ink sheet transport guide is driven by using the drive source of the transport means, and one of the gears constituting the drive means for driving the ink sheet transport guide is connected to the thermal head. A head pressurizing / separating means integrated with a head pressurizing shaft that is vertically movable is rotatably supported on the head pressurizing / separating means, and the gear is for moving the drive source constituting the drive means and the ink sheet conveyance guide. It is characterized in that it is interposed between the pinion gear and the pinion gear.

The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings. FIG. 1 is a front view showing a schematic configuration of an example of a printing apparatus (thermal line printer) of the present invention adopting a speed difference printing method, FIG. 2 is a plan schematic view thereof, and FIG. 3 is a schematic front view showing a main part thereof. Is. As described above, in the speed difference printing mechanism, printing is performed while controlling the transport speed of the ink sheet to 1 / n of the transport speed of the image receiving paper. In other words,
The usable length of the ink sheet is 1 / n of the printing area (printing length) on the image receiving paper side. For example, when n = 15, that is, when the ink sheet is conveyed at a speed that is 1/15 of the image receiving sheet conveyance speed, for example, when the printing area is 298 mm when the A4 image receiving sheet is conveyed, the used length of the ink sheet is The length is about 20 mm.

The speed difference printing mechanism shown in FIG. 1 faces above a platen roller 12 and a take-up roll 3 for winding up the ink sheet 1 that has finished printing, an ink sheet supply roll 4 for feeding an unused ink sheet. Ink that contacts the arranged thermal head 6 and the ink sheet 1 immediately after being fed from the supply roll 4 and moves the conveyance path of the ink sheet between a solid line position (initial pressing position) and a dotted line position (final position). A sheet conveying guide 7 and an image receiving sheet conveying means 9 (capstan 9a, pinch roller 9b) for conveying the image receiving sheet 2 wound around the outer periphery of the platen roller 12 and reversed and conveyed in the sheet discharge direction shown by the arrow. A drive source (motor) for driving the capstan 9a that constitutes the image receiving sheet conveying means 9.
10 and the platen roller 12 that rotates in the direction of the arrow and sandwiches the image receiving paper 2 and the ink sheet 1 between the thermal head 6 and the power transmission means (output) for transmitting the output of the ink sheet drive source 10 to the capstan 9a. By engaging the gear 13 a, the driven gear 13 b) 13, the holding means 11 that extends integrally from the thermal head 6 and rotates in the vertical direction around the fulcrum 11 a, and the thermal head 6 via the pressure spring 15. Mount the thermal head 6 to the platen roller 12
A head pressurizing / separating means 14 for moving the head pressurizing / separating means 14 up and down, a drive source 16 (motor) for vertically moving the head pressurizing / separating means 14, and a transmitting means 1 for transmitting an output from the drive source 16.
7 (output shaft 17a, driven gear 17b) and driven gear 17
Head pressing / separating means 1 integrated with the axis of b
Stabilizing the winding speed and tension by interposing between the holding shaft 18 integrally supporting the base end portion of No. 4 and the output gear 20 of the motor 19 for driving the winding roll 3 and the winding roll 3. A torque limiter 21 and the like for achieving the above are provided.

The present invention locks the rotation of the supply roll 4 while the new ink sheet 1 is fed from the supply roll 4 for a predetermined length, and then supplies the supply roll 4 and the printing portion (the platen roller 12 and the thermal head). The tension of the ink sheet located between the ink sheet and the pressure contact portion of the image sheet is controlled to be gradually loosened by the ink sheet conveyance guide 7 so that the amount of the ink sheet delivered is controlled to 1 / n of the conveyance speed of the image receiving paper 2. The characteristic feature is the configuration. Such control is executed based on a program stored in a ROM or the like of a control unit such as a microcomputer (not shown).

In the above structure, the image receiving paper 2 fed by the paper feeding means (not shown) is wound around the outer peripheral surface of the platen roller 12 by the image receiving paper conveying means 9. The image receiving paper conveying means 9 is driven by the drive source 10 via the power transmission means 13. In the thermal head 6, the head pressing / separating means 14 moves up and down around the holding shaft 18 by the rotation of the drive source 16 in two directions, and the head 6 is moved back and forth from the outer peripheral surface of the platen roller 12. The ink sheet 1 drawn out from the supply roll 4 is braked while being wound up by the winding roll 3 via the ink sheet conveyance guide 7, the thermal head 6, and the platen roller 12. That is, before the start of printing, the ink sheet transport guide 7 is at the position shown by the solid line in FIG. 1, and as the printing progresses, it is moved in the direction of the arrow by the ink sheet transport guide driving means, which will be described later, and finally moved to the dotted line position. Reach up to. The ink sheet supply roll 4 is locked so as not to rotate during the movement of the transport guide 7.
Therefore, the feeding speed of the ink sheet is controlled by the moving speed of the ink sheet transport guide 7. In other words, the length of the ink sheet that is fed before the supply roll 4 rotates and locks is set to be longer than the shortest distance between the supply roll 4 and the printing unit, and the portion that is pulled out for a long time is the ink sheet conveyance. The guide 7 removes the slack by pulling the ink sheet to the initial pressing position shown by the solid line in FIG. 1, but the guide 7 moves toward the final position shown by the dotted line as the printing progresses, The sheet is gradually delivered to the printing position at a speed of 1 / n of the image receiving paper. On the other hand, when cueing the ink sheet, the lock mechanism that locks the supply roll 4 is released to allow the supply roll to rotate freely. At this time, the unused ink sheet can be newly delivered by lowering the ink sheet transport guide 7 toward the solid line position.
The used ink sheet on the winding roll 3 side is not sent out from the winding side due to the effect of the torque limiter 21.

Next, an example of means for driving the ink sheet transport guide 7 will be described with reference to FIGS.
The ink sheet transport guide 7 is a roller extending in a direction orthogonal to the transport direction of the image receiving paper, and its both axial ends are rotatably supported by the lower end of the holding / driving mechanism 22. The holding / driving means 22 is a narrow and long member, and is supported by a plurality of guide projections (or rollers) 25 so as to be able to advance and retreat in the longitudinal direction thereof, and has a rack gear 22a provided at an appropriate upper position, The rack gear 22 a meshes with the pinion gear 26. The pinion gear 26 is fixed to a shaft 27 which is parallel to the guide 7, and the shaft 27 has both side plates 0.
It is rotatably supported by. Pinion gear 26
Simultaneously transmits the transmission mechanism 24 (output shaft 24a, driven gear 24
Since it is connected to b) and is rotated in the forward and reverse directions by the drive torque from the drive source 23, the holding / driving means 22 can move forward and backward in the longitudinal direction thereof. According to this configuration, n is 15
In the case of performing A4 printing as described above, since the ink sheet feed amount is about 20 mm, the movement amount of the conveyance guide is about 10 mm, although it depends on the distance between the parts. In addition,
Holding / driving means 22, pinion gear 26, transmission mechanism 2
4, the drive source 23 and the like constitute a drive unit for the ink sheet transport guide.

FIGS. 4 and 5 are structural explanatory views of an example of a lock mechanism for locking the rotation of the ink sheet supply roll 4, in which a ratchet gear 30 coaxially integrated with the ink sheet supply roll 4 is provided in a solenoid 31. The rotation of the ink sheet supply roll 4 is controlled by locking or unlocking by the locking claw 32 driven by. Reference numeral 33
Is a spring that biases the claw 32 in the locking direction. Locking claw 3
2 can rotate about a central fulcrum 32a, and when the solenoid 31 is in the OFF state as shown in FIG. 4, the spring 33 bites into the ratchet gear 30 to lock the roll 4, but the solenoid 31 is turned on. While the roller 4 is rotating, it disengages from the ratchet gear 30 against the spring 33 to allow the roll 4 to rotate. The transport guide 7 moves from the position shown by the solid line in FIG. 5 to the position shown by the solid line in FIG. 4 in the delivery state in which the lock is released for the beginning of the ink sheet.

According to the first embodiment described above, the ink sheet transport guide 7 is provided in the ink sheet transport path so as to control the delivery speed of the ink sheet that has been delivered for a predetermined length and once locked to the printing section. Therefore, in the constant speed feeding of the ink sheet, which is required in the speed difference printing mechanism, the ink sheet conveying path becomes simple, the feedback function by a sensor or the like becomes unnecessary, and the number of signals to be sent and received is reduced, and the apparatus is small in size. It is possible to simplify.

Next, FIG. 6 is an explanatory view of the essential parts of the second embodiment of the present invention, in which the same parts as those in the first embodiment are designated by the same reference numerals and their duplicate description will be omitted. Holding / driving means 22 (rack gear 22a) for driving the above-mentioned ink sheet conveyance guide using the drive source 10 of the image receiving paper conveying means 9;
The configuration in which the pinion gear 26 is driven is different. That is, the driving force from the driving source 10 is the power transmission means 13
Via the output gear 13a and the driven gear 13b that constitute
It is transmitted to the intermediate transmission means 41, and the intermediate transmission means 41 transmits to the gear 42 coaxial with the shaft 27 of the pinion gear 26. The intermediate transmission means 41 is a gear 4 that is coaxial with the driven gear 13b.
1a and a gear 41b rotatably supported by the side plate 0
And 41c are connected to the gear 42. Carrier 9
Between the driven shaft 13 and the driven gear 13b, and between the gear 42 and the shaft 27 of the pinion gear 26, clutches 40 and 43 such as electromagnetic clutches are interposed to turn torque transmission on and off.
By doing so, it is possible to arbitrarily switch the torque flow, drive only the transporting means 9, operate only the ink sheet transport guide 7, or operate both. The holding / driving means 22 and the pinion gear 2
6, drive source 10, power transmission means 13, gears 41, 42,
The clutches 40, 43 and the like form a driving unit for the ink sheet transport guide. According to the second embodiment, since the driving means of the ink sheet conveying guide 7 is mechanically connected to the image receiving paper conveying means 9 and is driven by using the same driving source 10, the apparatus can be downsized and the cost can be reduced. 7 (a) and 7 (b) are a plan view and a front view showing the configuration of the main part of the third embodiment of the present invention. Although the same reference numerals are given and duplicate description is omitted, in the configuration using a transmission mechanism including a pulley and a belt when the ink sheet transport guide 7 is operated by using the drive source 23 for moving up and down the thermal head 6. It's different.
That is, in this embodiment, the holding shaft 27 of the pinion gear 26 is
Is rotatably supported by a holding member 45 provided on the head pressing / separating means 14, and the belt 50 and the pulley 4 are different from the pulley 49 integrated at the end of the holding shaft 27.
6. The driving force from the driving source 23 is transmitted via the transmission means 24. According to this embodiment, when the head 6 is largely separated from the platen roller 12, the ink sheet conveyance guide 7 can also be separated from the ink sheet 1. Reference numerals 47 and 48 are a tensioner and a pressure spring for absorbing the slack of the belt 50 during rotation. That is, it is possible to eliminate the slack of the belt 50 when the head pressing / separating means 14 rotates about the shaft 18 and rises.

The holding / driving means 22, the pinion gear 26, the pulleys 46 and 49, the belt 50, the driving source 23 and the like constitute the driving means of the ink sheet conveying guide. According to the third embodiment, the ink sheet conveyance guide 7 is brought into contact with and separated from the ink sheet 1 in conjunction with the pressure contact / separation operation of the thermal head 6 with respect to the platen roller 12, so that the conveyance guide is not in printing. Since 7 moves to a position separated from the ink container, the conveyance guide 7 does not become an obstacle when the ink sheet is replaced, and the replacement workability can be improved. In addition, it becomes possible to use the ink sheet as a cassette.

FIG. 8 shows a fourth embodiment of the present invention, in which the same parts as those in the third embodiment are designated by the same reference numerals and a duplicate description will be omitted, but the head pressing shaft 18 is rotated coaxially. The configuration is different in that a gear 44 that is freely supported is directly connected between the pinion gear 26 and the output gear 24a of the drive source 23. By thus providing the gear 44 on the pressing shaft 18, the pinion gear 26 can continue to follow the gear 44 even if the head pressing / separating means 14 is rotated, and the number of parts can be increased. Absent. The holding / driving means 2
2, the pinion gear 26, the gear 44, the transmission mechanism 24, the drive source 23, and the like constitute a drive unit of the ink sheet conveyance guide. According to the fourth embodiment, one of the drive transmission means of the ink sheet transport guide 7 is rotatably provided on the pressurizing / separating means 14 to transmit the power to the transport guide 7. It is not necessary to provide a transmission system for the movement of the sheet conveyance guide mechanism linked with the thermal head 6, and it is possible to reduce the size and cost by reducing the number of parts.

[0017]

As described above, according to the present invention, the ink sheet transport guide 7 is provided in the ink sheet transport path to control the delivery speed of the ink sheet, which has been delivered for a predetermined length and temporarily locked, to the printing unit. Since the control is performed, the ink sheet conveyance path is simplified in the constant speed feeding of the ink sheet required in the speed difference printing mechanism, the feedback function such as a sensor is not necessary, and the number of signals to be transmitted and received is reduced. The size and simplification of the device can be achieved. Further, since the driving means of the ink sheet conveying guide 7 is mechanically connected to the image receiving paper conveying means 9 and is driven by using the same driving source 10, it is possible to further reduce the size and cost of the apparatus. You can

Further, since the ink sheet conveying guide 7 is brought into contact with and separated from the ink sheet 1 by interlocking with the pressure contact / separation operation of the thermal head 6 with respect to the platen roller 12, the conveying guide 7 is moved from the ink container when not printing. By moving to the separated position, the conveyance guide 7 does not become an obstacle when the ink sheet is replaced, and the replacement workability can be improved. In addition, it becomes possible to use the ink sheet as a cassette. Further, since one of the drive transmission means of the ink sheet transport guide 7 is rotatably provided on the pressurizing / separating means 14 to transmit the power to the transport guide 7, the thermal head of the ink sheet transport guide mechanism. It is not necessary to provide a transmission system for the movement linked to 6, and it is possible to reduce the size and cost by reducing the number of parts.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of an example of a printing apparatus of the present invention that employs a speed difference printing method of the present invention.

2 is a schematic plan view of the embodiment of FIG.

FIG. 3 is a schematic front view showing a main part of the embodiment shown in FIG.

FIG. 4 is a structural explanatory view of a lock mechanism of a supply roll.

FIG. 5 is a structural explanatory view of a lock mechanism of a supply roll.

FIG. 6 is a plan view showing the configuration of the main part of the second embodiment of the present invention.

7 (a) and 7 (b) are a plan view and a front view showing a main part configuration of a third embodiment of the present invention.

8 (a) and 8 (b) are a plan view and a front view showing a configuration of a main part of a fourth embodiment of the present invention.

[Explanation of symbols]

1 ink sheet, 2 image receiving paper, 3 ink sheet winding roll, 4 ink sheet supplying roll, 6 thermal head, 7 ink sheet conveying guide, 9 image receiving sheet conveying means (capstan 9a, pinch roller 9b), 10
Drive source, 11 holding means, 12 platen roller, 13
Power transmission means (output gear 13a, driven gear 13b),
14 head pressing / separating means, 15 pressing spring, 16
Drive source, 17 Transmission means (output shaft 17a, driven gear 17
b), 18 holding shaft, 19 motor, 20 output gear,
21 torque limiter, 22 holding / driving mechanism, 22a
Rack gear, 23 drive source, 24 transmission mechanism (output shaft 24a, driven gear 24b), 25 guide protrusion (or roller), 26 pinion gear, 27 shaft, 30 ratchet gear, 31 solenoid, 32 locking claw, 33 spring, 41 Intermediate transmission means, 41a, 41b, 41c gears, 42 gears, 40, 43 clutches, 45 holding members, 46 pulleys, 47 tensioners, 48 pressure springs, 49 pulleys, 50 belts,

Claims (3)

[Claims] 1. A conveyance speed Vi of an ink sheet with respect to a conveyance speed Vp of an image receiving paper is Vi = Vp / n (where n>
In a thermal line printer having a speed difference printing mechanism for printing as 1), an ink sheet take-up roll that winds up an ink sheet that has finished printing, an ink sheet supply roll that sends out an unused ink sheet, and the ink A mechanism for driving the sheet take-up roll, a lock mechanism for restraining or freeing the rotation of the ink sheet supply roll, and a mechanism located between the ink sheet supply roll and the printing position and intersecting the ink sheet. The ink sheet transport guide configured to be movable back and forth, a drive unit for driving the ink sheet transport guide, and a controller. The controller moves the ink sheet transport guide in the intersecting direction at a predetermined speed. An ink sheet conveying device characterized by realizing constant speed driving of an ink sheet by controlling the driving means so as to 2. The driving means for the ink sheet carrying guide is mechanically connected to the image receiving paper carrying means, and the driving means for the ink sheet carrying guide is driven by using the driving source of the image receiving paper carrying means. The ink sheet transporting device according to claim 1, wherein 3. A head pressurizing / separating unit in which one of the gears constituting the drive means for driving the ink sheet transport guide is integrated with a head pressurizing shaft for supporting the thermal head in a vertically movable manner. 2. The means is rotatably supported on the means, and the gear is interposed between a drive source forming the drive means and a pinion gear for moving the ink sheet conveyance guide. Ink sheet transport device.