JPH03230988A - Image recording apparatus - Google Patents

Abstract

PURPOSE:To appropriately change the retraction quantity of a thermal head by controlling a moving mechanism on the basis of an environmental condition such as detected humidity by providing a detection means detecting the environmental condition such as the humidity in the vicinity of recording paper and the moving mechanism bringing a thermal head into contact with a platen roller and retracting the same from the platen roller. CONSTITUTION:In the case of an environmental condition of high absolute humidity, recording paper P absorbs humidity to lose stiffness to become easy to generate curling or undulation and, in this state, the recording paper P becomes a state easy to generate jamming at the leading end P1 thereof. Herein, a moving mechanism 21 is turned ON to rotate a cam 29 and the thermal head 2 is shaken and displaced to release the pressure contact with the platen roller 1 and the thermal head 2 begins to retract from a pressure contact position E. Since the quantity of rotation of the cam 29 of the moving mechanism 21 is controlled on the basis of the absolute humidity detected by a humidity sensor 50 at this time by a microcomputer 58, the thermal head 2 appropriately changes in its retraction quantity to take the retracted position corresponding to the detected absolute humidity.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an image recording device. That is, the present invention relates to an image recording apparatus in which a thermal head is brought into heat-pressure contact with a platen roller through a recording paper, and an image is recorded on the recording paper.

"Prior Art" In such an image recording apparatus, the thermal head is pressed against the platen roller during recording, but is released from the pressure contact and is largely retracted when not recording. In other words, conventionally, the thermal head was always set to a large retraction amount when not recording, and the thermal head was set to a large retraction amount when not recording.

It was held in a position where it could not come into contact with the ink ribbon or the like.

Incidentally, recording paper is generally susceptible to environmental conditions such as humidity within the apparatus main body, and there is a relationship between the level of humidity and the amount of moisture absorption and expansion/contraction of the recording paper.

"Problems to be Solved by the Invention" By the way, the following problems have been pointed out in such image recording devices.

Depending on the environmental conditions, especially when the humidity is high, the recording paper absorbs moisture, loses its stiffness and stretches, and is more likely to curl or wave. In such a case, if the leading edge of the recording paper becomes a free end and is conveyed between the platen roller and the thermal head,
Recording paper tends to jam due to curls and waves, and is not conveyed properly. And such a situation is
Conventionally, for example, problems have arisen particularly when cut paper is used as the recording paper, when a developed technology is developed that enables image recording on a predetermined size of the recording paper, and so on.

This point has been pointed out in the past.

The present invention has been developed in view of the above-mentioned circumstances, and it is possible to prevent the recording paper from jamming by controlling the moving mechanism and appropriately changing the retraction amount of the thermal head based on the detected environmental conditions such as humidity. The purpose of the present invention is to propose an image recording device that can be transported stably without any problems.

[Means for Solving the Problems] The technical means of the present invention to achieve this object are as follows.

In this image recording apparatus, a thermal head is heated and pressed against a platen roller via a conveyed recording paper, and an image is recorded on the recording paper.

The image recording apparatus also includes a detection means for detecting environmental conditions such as humidity in the vicinity of the recording paper, and a moving mechanism for pressing the thermal head against the platen roller and retracting the thermal head.

During non-recording, when at least the leading edge of the recording paper is conveyed between the platen roller and the thermal head, the moving mechanism is controlled based on the environmental conditions detected by the detection means, and the tip is transferred to the thermal head. The retracted position is taken in accordance with the environmental conditions detected by the detection means.

"Function" Since the image recording apparatus according to the present invention includes such means, it functions as follows.

During recording, the thermal head is brought into heat and pressure contact with the platen roller by the moving mechanism, and an image is recorded on the recording paper.

When not recording, the thermal head is released from pressure contact with the platen roller by the moving mechanism and takes a retracted position. that time,
Since the moving mechanism is controlled based on environmental conditions such as humidity detected by the detection means, the amount of retraction of the thermal head changes as appropriate, and the thermal head takes a retracted position according to the environmental conditions.

Therefore, during non-recording, when the recording paper is generally fed between the platen roller and the thermal head with at least the free end, the recording paper is likely to curl or wave depending on the environmental conditions, especially when the humidity is high. However, since the recording paper is guided directly by a thermal head that takes an intermediate retreat position as necessary or via an ink ribbon, the recording paper is stably conveyed without jamming.

"Example" The present invention will be described in detail below based on the example shown in the drawings.

First, an overview of the thermal transfer recording device, including its configuration.

The ink ribbon thermal gutter unit, thermal head positioning, movement mechanism, etc. will be explained in this order.

The outline of the thermal transfer recording device is as follows.

The first part is a front explanatory view showing an embodiment of the present invention. This thermal transfer recording device is an example of an image recording device, and a thermal head 2 is heated and pressed against a platen roller 1 via a conveyed recording paper P and an ink ribbon R. The ink is thermally transferred surface-sequentially using a return method to record a color image.

To explain these in detail, a platen roller 1 is arranged at the center of the main body of the apparatus, and a thermal head 2 is arranged opposite to the platen roller 1 so as to be able to press against and separate from the ink ribbon R and the recording paper P. Also, a recording paper roll 3 is disposed at one end of the main body of the apparatus, and an unused roll of recording paper P
is wrapped. From the supply side to the paper discharge side of the recording paper P, a recording paper roll 3, a curl removing roller 4, a recording paper guide roller 5, and a grip roller 6 are arranged in order and parallel to each other to form a transport path. The driven rollers include the ribbon peeling guide 8, which is far away from the conveyance path in FIG. driven roller 1o,
A recording paper cutter 11 and the like are arranged. Reference numeral 12 denotes a recording paper guide plate which is appropriately filmed between these. Through such a single general feeding path, the recording paper P is sent out in the direction shown in the figure, and is then repeatedly conveyed back and forth multiple times between the reverse direction B direction shown in the figure and the incoming direction, during which it is returned to the B direction while thermal transfer is being carried out. After that, the paper is sent in the A direction and ejected.

To explain these in detail, first, in this thermal transfer recording apparatus, the recording paper P is conveyed by the grip roller 6. That is, the grip roller 6 is driven to rotate in forward and reverse directions by a drive source such as a stamping motor, and the recording paper P is sandwiched between the driven roller 7 and the grip roller 6, which is in pressure contact with the grip roller 6.
This is transported back and forth in the A direction and the B direction. The torque of this grip roller 6 is set to be the highest during the conveyance path of the recording paper P, and is the only criterion for determining the conveyance amount of the recording paper P. In addition, the gripping force is improved and slips are prevented, so that the recording paper P is conveyed with high precision and the line is set high. Specifically, the surface of the metal roller is roughened by blasting, and the surface of the roller is made of ceramic fine particles thermally sprayed or glued, etc. A rubber roller is used as the driven roller 7.

The platen roller l has a drum shape and can rotate in forward and reverse directions as it is driven by the reciprocating conveyance of the recording paper P by the grip roller 6 and the driven roller 7. That is,
This platen roller 1 is not rotationally driven, and first the recording paper P
When the recording paper P is conveyed in the incoming direction, that is, during non-thermal transfer in which the recording paper P is fed, it is completely free to rotate clockwise in the figure.

Furthermore, when the recording paper P is conveyed in the B direction, that is, during thermal transfer when the recording paper P is returned, a load of, for example, about 0.2 kg/cm is applied to the conveyed recording paper P, although the recording paper P can be rotated counterclockwise in the figure. It is designed to give a light hack tension. As this load means, for example, a configuration is adopted in which a torque limiter such as a magnetic powder type torque limiter and a one-way clutch (not shown) are attached to the shaft of the platen roller 1.

The tension roller 9 is pressed against its driven roller 10
The recording paper P is sandwiched between the rollers and the recording paper P, and tension is applied to the recording paper P during thermal transfer to prevent wrinkles and color misregistration. One row of tension rollers 9 is a rubber roller, and the driven roller 10 on the side that contacts the transfer surface of the recording paper P is a metal roller.

That is, during non-thermal transfer in which the recording paper P is conveyed in the input direction, the tension roller 9 is connected to a drive source via a one-way clutch (not shown) and rotates clockwise with a lower torque than the grip roller 6 described above. Driven. In other words, the torque of the tension roller 9 is set to such an extent that the recording paper P being conveyed does not slacken, the recording paper P does not slip between the grip roller 6 and its driven roller 7, and the surface peripheral speed of the tension roller 9 is grip roller 6
It is set slightly faster than the surface circumferential speed of .

Further, during thermal transfer when the recording paper P is conveyed in the B direction, the tension roller 9 is cut off from the drive source by the action of the one-way clutch, and is also cut off from the drive source by the action of the torque limiter etc. as in the platen roller 1 described above. Although it is rotatable in the counterclockwise direction in the figure, a certain load is applied to the recording paper P to apply a light brake-like tension to the recording paper P being conveyed.

The recording paper roll 3, which is a supply winding roll, can freely rotate counterclockwise in the figure during non-thermal transfer, and has a torque far lower than that of the grip roller 6, which is sufficient to prevent the recording paper P from slacking during thermal transfer. The recording paper P is rotated clockwise by a drive source at a set torque via a torque limiter or the like, and the recording paper P is wound up. Further, the curl removing roller 4 is of a fixed type, and is provided to remove curls since roll paper is used as the recording paper P.

By the way, this thermal transfer recording device is suitable for recording paper P, for example, A3.
In order to make it possible to thermally transfer an image to a predetermined size, such as the following, the following arrangement is made.

0 In other words, in this thermal transfer recording device, the ink of the ink ribbon R is thermally transferred in a field-sequential manner using a return method, but the thermal transfer is performed from the leading edge P of the recording paper P (in the feeding direction, which means the input direction, and in the return direction). In order to make it possible to print up to the vicinity of the rear end of the barrel (corresponding to the rear end in the direction of barrel B), even after the leading edge P1 of the recording paper P passes through the tension roller 9 and comes off, it is further returned in the direction of B, and the platen roller 1 and the thermal head Thermal transfer can be continued between the two. As a result, on the recording paper P, an image can be thermally transferred and recorded on a wide area up to a predetermined size without leaving a portion corresponding to the area between the tension roller 9 and the platen roller 1 as a non-thermal transfer portion. Even after thermal transfer of one color is performed in this manner, the recording paper P is further returned until its leading edge P is located slightly in the direction B from the thermal transfer position between the platen roller 1 and the thermal head 2.
The ink ribbon R is peeled off. Thereafter, the recording paper P is again sent in the opposite direction A in preparation for thermal transfer of the next color, and its leading edge P1 is conveyed between the platen roller 1 and the thermal head 2.

■ This is how the thermal transfer recording device works.

Next, the ink ribbon R will be described.

Inkliphone R used in thermal transfer recording devices is
It is in the form of a film sheet with approximately the same width as recording paper P, etc., and pigment-based heat-melting or dye-based heat-sublimating solid ink is repeatedly applied over a fixed length in the order of three primary colors: yellow, macenta, and cyan. has been done.

The 111 feeding system of the ink ribbon R runs from the supply side to the winding side as shown in FIG.
A ribbon guide roller 14, a ribbon guide roller 15, a ribbon position detection sensor 16, a pinch roller 17 and its driven roller 18, a ribbon take-up roll 19, etc. are arranged in this order with their axes parallel to each other. A ribbon winding roll 19 is disposed on the recording paper roll 3 side, and a ribbon supply roll 13 is disposed on the recording paper cutter 11 side, and the ink ribbon R is conveyed in the direction C in the figure.
When the ribbon reaches the ribbon guide roller 15, it is guided between the platen roller 1 and the thermal head 2 described above.

To explain these in detail, the ink ribbon R is conveyed by a pinch roller 17, supplied from a ribbon supply roll 13, and wound around a ribbon take-up roll 19. That is, the pinch roller 17 is rotationally driven clockwise in the drawing by a drive source, pinches the ink ribbon R between it and the driven roller 18 that is pressed against it, and conveys the ink ribbon R in the direction C by its gripping force. . The driven roller 18 is a roller that is pressed against the transfer surface side of the ink ribbon R coated with ink, and is a metal roller.

An unused ink ribbon R is wound around the ribbon supply roll 13. Although the ribbon supply roll 13 can be rotated counterclockwise in the figure, a certain load is applied to the ribbon supply roll 13, so that the ink ribbon R that is being supplied has a light weight. It is designed to provide a brake. In other words, the ribbon supply roll 13 applies tension to the ink ribbon R between it and the pinch roller 17 etc. by means of an attached load means, and prevents the ink ribbon R from being fed out or supplied more than necessary. Further, the used ink ribbon R, which has been separated from the recording paper P by the ribbon separation guide 8 after thermal transfer, is wound around the ribbon winding roll 19. That is, the ribbon winding roll 19 is rotationally driven in the counterclockwise direction in the figure by a driving source via an I.luchrimic or the like, and the set torque is as follows.
The torque is regulated much lower than the torque of the pinch roller 17,
It is designed not to have any adverse effect on the thermally transferred image.

The ink ribbon R is like this.

Next, the thermal head unit 20 will be described.

FIG. 2 shows a thermal rad unit 20 of this thermal transfer recording apparatus. FIG. 2 is a front explanatory view of main parts showing a moving mechanism 21 and the like. FIG. 3 is a perspective view of the thermal head unit 20. The following description will be made with reference to FIGS. 2 and 3 in addition to FIG. 1.

First, a unit support shaft 22 is attached to the main body of the apparatus in the same axis direction as the conveyance system for the recording paper P and ink ribbon R described above. It is possible to turn 4 times. Further, 23 is a unit support frame provided on the main body of the apparatus, and a bracket 24 is fixed to this unit support frame 23.

The thermal head unit 20 includes a thermal head 2 located opposite to the platen roller 1, and a heat sink portion 2 in which the thermal head 2 is fixedly attached and has a substantially elongated plate shape.
5, a bearing 26 fixed to the center of one side of the heat sink part 25 in a direction perpendicular to the unit support shaft 22, and a bearing 26.
and the joint shaft 27 attached between the unit support shaft 22 and the other side of the heat sink portion 25 and the unit support shaft 22
A pressure plate part 28 arranged in between and formed in a bent manner, an opposing roller 30 protruding from the pressure plate part 28 and pressed against a cam 29 of the moving mechanism 21, which will be described later, and interposed between the pressure plate part 28 and the gradient 24. The first spring 31 and the second spring 32 interposed between the pressure plate part 28 and the heat sink part 25
and a third spring 33 interposed between the bearing 26 and the unit support shaft 22.

(2) To explain these in detail, first, the thermal head 2 is provided with a large number of heating elements, which are heating resistors, arranged in a line, and each dot is selectively heated with electricity.
This is performed based on monochromatic component data, which is hue image information for each of the three primary colors sent during thermal transfer. and thermal head 2
As will be described later, based on the rotation of the cam 29 of the moving mechanism 21, the platen roller 1 is pressed into contact with the platen roller 1 during thermal transfer (see FIG. 2), and during non-thermal transfer, the pressure is released and separated, and the cam 29 takes a retracted position of a predetermined retract amount (see FIG. 2). For example, see Figure 1).

The heat sink part 25 holding the thermal head 2 is
It is arranged parallel to the unit support shaft 22, has a substantially elongated plate shape, and is provided with heat dissipation fins, and a bearing 26. Joint shaft 27.
It is connected to the unit support shaft 22 via a third spring 33 and the like. Thus, the heat sink portion 25 is held by the rotatable unit support shaft 22 so as to be swingable about the rotatable unit support shaft 22 as a fulcrum. On the other side of the heat sink portion 25, a ribbon peeling guide 8 is provided to protrude substantially downward, that is, toward the transport path of the recording paper P, and a protruding piece 34 is formed substantially laterally, that is, in a direction perpendicular thereto. A second spring 32 is interposed substantially below, that is, between the top surface 35 of the pressure plate portion 28 and the top surface 35 of the pressure plate portion 28 .

The pressure plate portion 28 includes a top surface 35, a base portion 36, and an end portion 37. That is, the pressure plate part 28 has a top surface 35 on which the first spring 31 is interposed between the bracket 24 and the opposing roller 30 is protruded and held, and a unit support shaft which is integrally provided in a bifurcated manner on the top surface 35. a base portion 36 rotatably attached to the heat sink portion 22; and an end portion 37 bent downward from the other side of the top surface 35 and capable of locking the projecting piece 34 of the heat sink portion 25.
It is equipped with

Now, the entire thermal gear unit 20 is configured to swing back and forth around the unit support shaft 22 based on the rotation of the cam 29 of the moving mechanism 21 and the tensile force of the first spring 31. That is, in the thermal head unit 20, first, the heat sink portion 25 is connected to the unit support shaft 22 by the joint shaft 27, etc., and can be oscillated about the unit support shaft 22, and is moved by the tensile force of the first spring 31. The opposing roller 30 is constantly pressed against the cam 29, and the tension of the first spring 31 causes the pressure plate portion 28. Its end 37. The heat sink portion 25 and the like can be lifted up via the protruding piece 34 that is engaged with this, so that the heat sink portion 25 and the like can follow the rotation of the cam 29 and undergo reciprocating rocking displacement. As the thermal head unit 20 reciprocates and oscillates, the thermal head 2 fixed to the heat sink portion 25 is brought into pressure contact with the platen roller 1.

Be turned away.

The first spring 31, which is a suspension spring, is capable of lifting the entire RAD unit 20 to the thermal
The opposing roller 30 is pressed against the cam 29 with a predetermined reaction force,
This functions to ensure the position of the thermal head 2, and has sufficient tensile force. At this time, considering the weight of the entire thermal head unit 20, this tensile force needs to be quite strong, but when the thermal head 2 is pressed against the platen roller 1 (see Fig. 2).
If left as is, an excessive reaction force will be applied to the cam shaft 38 of the cam 29, which may cause the cam shaft 38 to bend. Therefore, in the illustrated example, a balance weight 39 is attached to the other end of the connecting shaft 27 on the opposite side from the bearing 26 with the unit support shaft 22 as the center, and this balance weight 39 allows the thermal head to be applied to the first spring 31. The weight of the unit 20 is reduced. Therefore, it is not necessary to make the tensile force of the first spring 31 strong, and it is possible to prevent the camshaft 38 from being bent during pressure contact.

The second spring 32 for pressure contact is compressed between the pressure plate portion 28 and the heat sink portion 25 based on the rotation of the cam 29 when the thermal head 2 is pressed against the platen roller 1 .

It functions to bring the thermal head 2 into appropriate pressure contact with the platen roller l by a resilient force of, for example, about 3 kg to 4 kg.

The thermal head unit 20 has this structure.

Next, positioning of the thermal head 2 will be described.

In this thermal head unit 20, the third spring 9 ring 33 is wound around the joint shaft 27 in a compressed state between the unit support shaft 22 and the bearing 26, and the unit support shaft 22 is fixed.
The bearings 26 are held at predetermined intervals. An adjustment screw 40 is attached to one end of the joint shaft 27 via the bearing 26.

Further, a positioning plate 41 is provided between the bearing 26 and the unit support shaft 22. That is, one bent end of the positioning plate 41 is interposed and fixed between the bearing 26 and the adjusting screw 40, and the other end of the positioning plate 41 is connected to the unit support shaft by screws 43 through two elongated holes 42. It is fixed at 22. That is, as shown in FIG. 3, an elongated hole 42 is formed at the other end of the positioning plate 41 in a direction perpendicular to the unit support shaft 22, and a reference elongated hole 44 is formed between these elongated holes 42.
is parallel to these and similarly long. A position scale 45 is attached to this reference elongated hole 44.
A reference mark 46 is attached on the unit support shaft 22 that can be visually recognized through the reference mark 46.

In addition, a screw receiving member 47 is provided at each end of an example of the substantially long plate-shaped heat sink portion 25 arranged near the center on one side, and a mounting ring is provided on the unit support shaft 22 side opposite to this. 48 is provided, and the screw receiving member 47
and the mounting ring 48 are connected by fine adjustment screws 49, respectively.

By the way, it is not easy to assemble and position the thermal head unit 20 so that the heating element of the thermal head 2 can accurately press against the platen roller 1 during thermal transfer. On the other hand, since the illustrated example has the above-mentioned configuration, when assembling the thermal head unit 20, the thermal head 2 can be accurately and easily positioned by first performing rough positioning and then making fine adjustments and misalignment adjustments. It has become so.

That is, when assembling, first, by turning the adjustment screw 40 in the forward and reverse directions, the third spring 33 expands and contracts, and the distance between the bearing 26 and the unit support shaft 22 is adjusted as appropriate. The position relative to the platen roller 1 changes. This is because when the adjustment screw 40 is turned, the positioning plate 41 moves and moves relative to the 1 position scale 45 of the reference elongated hole 44 or the immovable reference mark 46, so this can be read and referenced to determine its relative position. This is done while checking for any discrepancies. In this manner, when assembling the thermal head unit 20, first, the adjusting screw 40 is used to adjust the heating element of the thermal head 2 to the platen roller 1 during thermal transfer.
Rough positioning is performed in order to make pressure contact with.

Thereafter, by turning both fine adjustment screws 49 in the forward and reverse directions as necessary, the distance between the bearing 26, that is, the heat sink portion 25, and the unit support shaft 22 (that is, the distance in both the left and right directions in FIGS. 1 and 2) is adjusted. is further finely adjusted, and in order to make the heat sink part 25 parallel to the unit support shaft 22 (
(see Figure 3), the left and right deviations are adjusted. In this manner, during assembly, fine adjustment and displacement adjustment are performed using the fine adjustment screw 49 so that the heating element of the thermal gutter 2 is accurately pressed against the platen roller 1 during thermal transfer.

Furthermore, the positioning plate 41 is inserted into the screw 4 through the elongated hole 42.
Since it is fixed to the unit support shaft 22 at 3, even if the adjustment screw 40 loosens due to vibration etc., the above-mentioned positioning of the unit 1, the sink section 25 and the thermal head 2 will be stable. Retained. In the illustrated example, the thermal head 2 is positioned accurately and easily in this manner.

The thermal head 2 is positioned in this manner.

Next, the moving mechanism 21 and the like will be described.

FIG. 4 is a side view of the moving mechanism 21, and the explanation will be given below with reference to FIG. 4 in addition to FIGS. 1 and 2.

This thermal transfer recording apparatus further includes a detection means for detecting environmental conditions such as humidity near the recording paper P, and a moving mechanism 21 for pressing the thermal head 2 against the platen roller 1 and retracting it.
It has the following. During non-thermal transfer, when at least the leading edge P1 of the recording paper P is conveyed between the platen roller 1 and the thermal head 2, the moving mechanism 21 is controlled based on the environmental conditions detected by the detection means, and the thermal head 2 The retracting position includes a mid-retreat position D (see FIGS. 9 and 10, which will be described later) in which the recording paper P can be guided via the ink ribbon R.

3 To explain these in detail, first, for example, a humidity sensor 5o is used as the detection means, and this humidity sensor 50 is
It is disposed near the recording paper roll 3 and other recording paper P in the apparatus main body, and detects environmental conditions such as absolute humidity and other relative humidity in the vicinity.

The moving mechanism 21 includes a drive source 51 such as a guard moke, a camshaft 38 connected to the drive source 51 at one end, a bearing 53 provided on a side frame 52 to hold the other end of the camshaft 38, and a camshaft 38. the cam 29 fixed to the cam shaft 38, the first detection plate 54 and the second detection plate 55 fixed in line near the other end of the camshaft 38, and the positions corresponding to the first detection plate 54 and the second detection plate 55, respectively. a first photo sensor 56 and a second photo sensor 57 held on the side frame 52;
It is equipped with a microcomputer 58 and the like.

The cam 29 has a disc shape, is eccentrically fixed to the cam shaft 38, and is connected to the opposing roller 3 of the thermal head unit 20 described above.
It is pressed against 0. Therefore, the camshaft 38 and the cam 29
When the is rotated, the opposing roller 30 is guided by the roller 4 and driven in a reciprocating manner, and the thermal head unit 20 is reciprocated and oscillated, thereby moving the thermal head 2 from the lowered pressure contact position E (see Fig. 2) to the upper and retracted maximum position. The retracted position F (see FIG. 1) and the intermediate retracted position D (see FIG. 9, etc. described later) are sequentially taken.

In other words, when the large-diameter portion of the eccentric cam 29 comes into pressure contact with the opposing roller 30, pressing force is applied to each member of the thermal head unit 20, pushing it down, and the thermal head 2 takes the pressure position E and comes into pressure contact with the platen roller 1. (See Figure 2). Also, when the small diameter portion of the cam 29 comes into pressure contact with the opposing roller 30, each member of the thermal head unit 20 is lifted up by the tensile force of the first spring 31, and the thermal head 2 is lifted up greatly from the platen roller 1. Take the maximum retracted position F (see Figure 1). Further, when the intermediate portion of the cam 29 comes into pressure contact with the opposing roller 30, each member of the thermal head unit 20 is slightly lifted, and the thermal head 2 is moved to a halfway retracted position between the pressing position E and the maximum retracted position F. 5 (see Figure 9, etc.). At this halfway retracted position, the thermal head 2 can guide the curled or wavy leading edge P of the recording paper P via the ink ribbon R.

The first detection plate 54 has a semicircular shape and is rotated by the cam shaft 38 in synchronization with the cam 29 . Then, the first photo sensor 56 detects the position of the first detection plate 54 corresponding to the rotational position of the cam 29 that positions the thermal head 2 at the pressure contact position E and the maximum retraction position F. Also, the second detection plate 5
5 has a disk shape and rotates in synchronization with the cam 29 by a cam shaft 38. A notch 59 is formed in the second detection plate 55 corresponding to the rotational position of the cam 29 that causes the thermal head 2 to take the mid-retreat position iD, and this notch 59 is connected to the second photo sensor 57. detected.

The microcomputer 58 includes a humidity sensor 50 and a first
Photo sensor 56. Detection signals from the second photo sensor 57 and others are inputted, and on/off signals thereof are outputted to the drive source 51 as appropriate based on these signals. Note that controlling the moving mechanism 21 based on environmental conditions, that is, appropriately setting the retraction amount of the thermal head 2 so that the thermal head 2 takes the intermediate retraction position and the maximum retraction position F, is important for recording during non-thermal transfer. It is sufficient that the process is performed when the leading edge P, which is the free end of the paper P, is conveyed to the thermal transfer position between the platen roller 1 and the thermal head 2, and during other non-thermal transfers, the thermal head 2 moves to the maximum retreat position F. You can also take it.

The moving mechanism 21 and the like are configured as described above.

The above is the explanation of the configuration, etc.

The operation etc. will be explained below.

5, 6, 7, 8, 9, and 10 are explanatory front views showing each stage of the operation of this embodiment, and these drawings will also be referred to below. I will explain. This thermal transfer recording device has the following steps: (1) initial stage, (2) first feeding stage, (3) thermal transfer stage, (4) peeling stage, (5) next feeding start stage, (6) next feeding stage. , (7) Operations follow the paper ejection stage, etc. Each of these stages will be explained below.

7 (1) Initial stage FIG. 5 shows an initial stage in which the recording paper P is fed to the recording paper cutter 11 and set. That is, at this stage, the thermal head 2 is first located at the maximum retracted position F, the moving mechanism 21 is turned off, and the thermal head unit 2
0 also stops, and the thermal head 2 maintains the maximum retracted position F. Note that during the initial stage setting, the recording paper P is sent out from the recording paper roll 3 by the clockwise rotation of the grip roller 6, passes through the platen roller 1, and is further transferred to A.
When the sheet of paper is conveyed in the same direction as the recording paper cutter 11, it is stopped and cut, and the length up to the leading end P is made uniform. The ink ribbon R is fed forward in the C direction from the ribbon supply roll 13 by the clockwise rotation of the pinch roller 17, and the feeding is checked by the ribbon position detection sensor 16, and the first color ink barrel yellow is fed. When the ink reaches the thermal transfer position between the platen roller 1 and the thermal head 2, it stops and cueing is performed.

8 (2) First feeding stage FIG. 6 shows the first feeding stage in which the recording paper P is further fed. That is, in response to the recording start command, at this stage, the thermal head 2 still takes the maximum retracted position iF, and the ink ribbon R also stops and maintains that position after the cueing is completed.

Then, only the recording paper P is moved further by the recording paper cutter 1 in six directions.
1, and when the leading edge P1 is advanced by one recording size from the thermal transfer position, for example, in the case of A3 size, it is conveyed by 420 mm, and then stopped.

(3) Thermal transfer stage FIG. 7 shows the thermal transfer stage in which the recording paper P is returned. That is, at this stage, the moving mechanism 21 is turned on, the cam 29 is rotated, the thermal head unit 20 is oscillated, and the thermal head 2 moves from the maximum retracted position F to the halfway retracted position and descends to press contact. The ink ribbon R is brought into pressure contact with the platen roller 1 via the ink ribbon R and the recording paper P, and then stopped.

At the same time, the recording paper P is conveyed 9 in the direction B by rotationally driving the grip roller 6 in the counterclockwise direction, is returned in the opposite direction to the previous feeding direction, and is wound up again on the recording paper roll 3. . Also, the ink ribbon R is rotated clockwise again by the pinch roller 17.
The recording paper P is advanced in close contact with the recording paper P in the same direction C direction. Then, the heating element of the thermal head 2 is selectively energized and heated based on the monochromatic component data for one color of yellow, and the yellow ink applied to the ink ribbon R is transferred to the recording paper P.
An image of one color of yellow is recorded.

(4) Peeling stage FIG. 8 shows the stage of peeling off the ink ribbon R.

That is, at this stage, the thermal head 2 is still in the pressure contact position E and the energization is stopped, and the recording paper P, on which the thermal transfer of the first color yellow has been completed, is further conveyed slightly in the direction B, and its leading edge P1 touches the platen roller 1. It is returned to the direction B slightly from the thermal transfer position between the thermal heads 2 and stopped. At the same time, the ink phone R is also further fed forward in the C direction, separated from the recording paper P by the ribbon separation guide 8, and is wound up on the used part phone winding roll 19 in sequence, and then stopped.

(5) Next feed start stage FIG. 9 shows the next feed start stage in which the leading end Pl of the recording paper P is sent between the platen roller 1 and the thermal head 2. That is, at this stage, the recording paper P is again sent in the direction A by the grip roller 6, which is rotationally driven in a clockwise direction, in order to prepare for the thermal transfer of the next second color, magenta, in the field sequential manner, and its leading edge P1 is the free end. The paper is transported between the platen roller 1 and the thermal head 2. At that time, depending on the environmental conditions, for example, when the absolute humidity is high, the recording paper P may absorb moisture and lose its elasticity, causing curls and waves, and if left as it is, it may easily jam at the leading edge P, etc. Become.

Now, the thermal head 2 is released from pressure contact with the platen roller 1 by turning on the moving mechanism 21, rotating the cam 29, and rockingly displacing the thermal head unit 20. Begin evacuation from 11E. At that time, the amount of rotation (rotation angle) of the cam 29 of the moving mechanism 21 is controlled by the microcomputer 58 based on the absolute humidity detected by the humidity sensor 50. It changes as appropriate and takes a retreat position according to the detected absolute humidity.

In other words, high absolute humidity is detected by the humidity sensor 50,
When the second photo sensor 57 detects the notch 59 of the second detection plate 55, the microcomputer 58 turns on the moving mechanism 21, and the cam 29 and thermal head unit 20 stop at that position, as shown in FIG. The thermal head 2 stops at the halfway retracted position. Therefore, even if the recording paper P is curled or wavy due to the above,
In this way, the thermal head 2, which takes the halfway retracted position, is guided via the ink ribbon R, so that it does not jam (
It is transported in a stable manner. Moreover, these can be realized at an excellent cost in terms of simple construction and the number of recording paper guide plates 12 can be reduced.

On the other hand, when the humidity sensor 50 detects low absolute humidity, the recording paper P is unlikely to curl or wave 2 and there is no risk of jamming, so the second photo sensor 57 detects the second detection plate 55. Even if the notch 59 is detected, the microcomputer 58 does not turn off the moving mechanism 21 and the cam 29 continues to rotate, and the thermal head unit 2o is lifted up with a large swinging displacement, and the thermal head 2 is moved to the maximum retraction. It will take position F. In other words, regardless of FIG. 9, the thermal head 2 passes from the pressure contact position E, passes through the halfway retraction position, reaches the maximum retraction position F, and stops, and the platen roller 1 is retracted greatly, and the ink ribbon R9 is moved to the recording paper sheet. etc. (see Figure 1, etc.).

(6) Next feeding step In FIG. 10, the leading edge P1 of the recording paper P is
Indicates the next feed stage that has been sent up to. That is, in this next feeding step, the recording paper P is further conveyed in the direction A by the grip roller 6, and its leading edge P is sent to the tension roller 9 as shown in the figure, in accordance with the above-mentioned (2) first feeding step. After that, the recording paper passes through a recording paper printer 11, is fed by a predetermined recording size, and then stops, completing preparations for thermal transfer of the next second color, magenta.

During this time, if the thermal head 2 has taken the halfway retracted position and stopped as described above, the following will occur. That is, while the recording paper P is being conveyed in this manner, the amount of conveyance of the recording paper P is checked, for example, by a pulse counting method that counts the pulses of the stepping motor that is the drive source of the grip roller 6. As shown in FIG. 10, when it is confirmed that the leading edge P of the recording paper P is caught between the tension roller 9 and its driven roller 10, the microcomputer 58 turns on the moving mechanism 21. The cam 29 rotates, the thermal head unit 20 is oscillated and lifted, and the thermal head 2 is
It takes the maximum evacuation position F from the halfway evacuation position and stops.

On the other hand, as described above, the thermal head 2 is at the pressure contact position E.
However, if the thermal head 2 or the like has already stopped at the maximum retracted position F, such an operation of the thermal head 2 and the like is not necessary.

4 At this stage, the next magenta ink is located on the ink ribbon R.

After that, by repeating each step from the above-mentioned (3) thermal transfer step, the second color magenta and the third color
Thermal transfer of cyan color is performed in the same way.

(7) Paper discharge stage When the thermal transfer of the third color cyan is completed and the next feeding stage (6) is reached, the recording paper P is further conveyed in the A direction and then cut by the recording paper cutter 11. The paper is then ejected. For example, in the case of A3 size, cutting is performed after the leading edge P of the recording paper P is conveyed to a position 420 mm from the recording paper cutter 11.

Note that the thermal head 2 is stopped at the maximum retracted position F.

In this thermal transfer recording apparatus, by tracing each step in this manner, the three colors of ink of the ink ribbon R are sequentially thermally transferred and overlapped onto the recording paper P, thereby recording a color image.

The above is the explanation of the operation, etc.

5 "Others" Firstly, in the embodiment described above, the retraction amount of the thermal head 2 is two times larger than the mid-retraction position and the maximum retraction position F.
Although the present invention is made up of stages, the present invention is not limited to this, and may be formed in more stages. For example, FIG. 11 is an example of a graph showing the relationship between absolute humidity and the amount of retraction of the thermal head 2. Divide into stages,
Correspondingly, the amount of retraction of the thermal head 2 may be set to three levels: a first intermediate retraction position where the amount of retraction is the smallest, a second intermediate retraction position where the amount of retraction is the next smallest, and a maximum retraction position F. In this case, the aforementioned second detection plate 55 has two
Notches 59 are formed. Further, in the case of making the cutouts finer and multistage, a plurality of corresponding notches 59 are formed, but an encoder may be used instead of these.

Secondly, according to the present invention, the amount of retraction of the thermal head 2 can be set in a substantially analog manner rather than in a multi-stage digital manner. For example, FIG. 162 is another example of a graph showing the relationship between absolute humidity and the amount of retraction of the thermal head 2. As shown in the same figure, the absolute humidity detected by the humidity sensor 50 is approximately Correspondingly, the thermal head 2 may be retracted. In this case, instead of the above-mentioned detection plate 55,
It is necessary to use an encoder or the like with better resolution.

In the thermal transfer recording apparatus of the above-described embodiment, a color image is recorded by a field sequential method, but the retraction amount of the thermal head 2 is the same throughout the thermal transfer of each color. However, for example, as thermal transfer progresses, the thermal head 2
It is expected that the paper quality and other conditions of the recording paper P will change due to the heating of the recording paper P, and the occurrence of curl will be reduced. It is also conceivable to set a larger retraction amount for the third color, cyan, during thermal transfer.

In this way, the retraction amount of the thermal head 2 may be finely changed for each color.

Fourth, these first. Second. This is common to the third point, but by setting the amount of retraction of the thermal head 2 in detail, the amount of retraction is made small only in the minimum necessary case, and the amount of retraction is made as large as possible in other cases. This has the advantage that stains due to rubbing of the paper P are prevented. In other words, generally speaking, the larger the retraction amount of the thermal head 2 is, the more the recording paper P will not come into unnecessary contact with the ink ribbon R, etc., and the dirt caused by the friction will be prevented. Note that, on the premise that the retraction amount of the thermal head 2 can be set freely and finely in this way, in the above-described embodiment, the thermal head unit 20 is held in a swingable manner.

Fifth, in the thermal transfer recording apparatus of the above embodiment, roll paper was used as the recording paper P, and three color inks were thermally transferred to record a color image. However, in the present invention, cut paper may be used instead of roll paper as the recording paper P, two colors of ink may be thermally transferred, and one color ink may be thermally transferred once. Sixthly, in the thermal transfer recording device of the above-mentioned embodiment, a method was adopted in which roll paper was used and thermal transfer was performed when returning the paper. At the start of thermal transfer of yellow, which is the first color, the leading edge P of the recording paper P.

becomes the free end and connects platen roller 1 and thermal head 2.
There was no need to set the retraction amount of the thermal head 2 to a predetermined value. However, if this method is not used,
For example, if Kan) paper is used as the recording paper P,
Even at the start of the first thermal transfer, the leading edge P of the recording paper P becomes a free end and is generally fed between the platen roller 1 and the thermal bend 2, so it is necessary to appropriately change the retraction amount of the thermal head 2 by a predetermined saw. is born.

Seventhly, the present invention is not limited to a thermal transfer recording device that thermally transfers ink from an ink ribbon R to a recording paper P as in the above embodiment, but can be widely applied to various other image recording devices. For example, if thermal paper is used as the recording paper P without using the ink phone R, the image is transferred to the recording paper by conveying the recording paper P, which is the thermal paper, and heating and pressing it against the platen roller 1 with the thermal head 2. It is also applicable to an image recording device that records on P. In this case, the leading edge P of the recording paper P is directly guided by the thermal head 2 positioned at the halfway retracted position.

Eighth, to explain in more detail the above-mentioned curling and waving of the recording paper P, such curling and waving occur especially when the humidity is high as follows. That is, when roll paper is used as the recording paper P, curling is generally likely to occur, and on the other hand, when cut paper is used as the recording paper P, waving is generally likely to occur. Furthermore, when special paper whose surface has been calendered, etc. is used as the recording paper P, the front and back surfaces have different fiber states and therefore have different amounts of expansion and contraction due to moisture absorption. Curls are likely to occur. In addition, when coated paper is used as the recording paper P, the front surface, which is the coated printing surface, and the back surface, which is plain paper, have different amounts of moisture absorption, so the amount of expansion and contraction is also different, which makes it particularly difficult to curl. Likely to happen.

"Effects of the Invention" As explained above, the image recording device according to the present invention has the following features:
By controlling the movement mechanism and changing the retraction amount of the thermal head as appropriate based on the detected environmental conditions such as humidity,
Demonstrates the following effects.

In other words, the thermal head guides the recording paper being conveyed directly or via an ink ribbon as necessary, so even if the recording paper is curled or wavy, it will not jam and will remain smooth and stable. Become transported. In this way, the problems that existed in this type of conventional example are completely eliminated, and the effects of the present invention are remarkable and great.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of an image recording device according to the present invention.
It is a front explanatory view. FIG. 2 is a front explanatory view of the main parts showing the thermal radar unit, moving mechanism, etc. FIG. 3 is a perspective view of the thermal head unit. FIG. 14 is a side view of the moving mechanism. FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 9, and FIG. 10 are explanatory front views showing each stage of the operation of the embodiment. Figure 5 shows the initial stage when the recording paper is fed to the recording paper cutter, Figure 6 shows the initial feeding stage when the recording paper is further fed, Figure 7 shows the thermal transfer stage when the recording paper is returned, and Figure 8 shows the thermal transfer stage when the recording paper is returned. The figure shows the separation stage from the ink ribbon, Figure 9 shows the next feeding start stage where the leading edge of the recording paper is fed between the platen roller and the thermal head, and Figure 10 shows the stage where the leading edge of the recording paper is fed to the tension roller. The next feeding stage is shown respectively. 11 and 12 are graphs showing the relationship between absolute humidity and the amount of retraction of the thermal head, with FIG. 11 showing one example and FIG. 12 showing another example. 1...Platen roller 2...Thermal head 21...Movement mechanism 2 5 0...Humidity sensor (detection means) D...Midway retreat position E...Pressure position F...Maximum retreat position P...Recording paper P,...,, tip 3 Fig. 1 Fig.

Claims (1)

[Claims] An image recording device in which a thermal head is heated and pressed against a platen roller through a conveyed recording paper to record an image on the recording paper, the apparatus detecting environmental conditions such as humidity near the recording paper. and a moving mechanism that presses and retracts the thermal head from the platen roller, and when not recording, at least when the leading edge of the recording paper is conveyed between the platen roller and the thermal head. , the moving mechanism is controlled based on the environmental condition detected by the detecting means, and the thermal head takes a retracted position according to the environmental condition detected by the detecting means. .