JPH0740564A - Recording device - Google Patents

Abstract

PURPOSE:To uniformly heat a thermal head in the cross direction also in heating it with a plurality of small-sized heaters by providing a heating means on a support body in the direction crossing a row of heat generating resisters of the thermal head at a position furthermost from the row and in a symmetrical way with the direction of the row with center at a temperature measuring element. CONSTITUTION:Temperature of a thermal head 12 is detected by a temperature measuring element 92 such as thermistor provided inside the center in the cross direction, cooled with blast or heated as occasion demands, and kept in a predetermined temperature. Further, at right-and-left side parts of a heat sink, coin-shaped heaters for heating a head 12 are provided. These heaters are arranged symmetrically with respect to the right and left in the cross direction of the head 12 with center at the element 92 and at a position furthermost from a row of heat generating resistors of the head 12. Accordingly, when the heaters are heated, the temperature of the installed position of the element 92 becomes the lowest at the cross direction of the head 12. In the case of the heater, as distribution irregularity of temperature occurs in heat conduction of the head 12, the heating irregularity is eliminated by controlling the temperature of the thermal head with a control device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus for thermal transfer recording of ink on a transfer paper, and more particularly to a thermal head mechanism section to which a thermal head is mounted.

[0002]

2. Description of the Related Art Conventionally, color ink on the surface of a transfer paper is melted by heat of a thermal head (heat melting property) or sublimated (heat sublimation property) to form characters or image information at a desired position on a recording paper. There is known a recording device that performs color recording accordingly. The transfer paper is formed by applying color inks of respective colors such as yellow, magenta, cyan, and black (hereinafter simply abbreviated as Y, M, C, and B) in the longitudinal direction in a dana-shaped manner in a frame-sequential manner. The thermal head is pressed against the recording paper via the transfer paper, and the recording paper is reciprocated to sequentially transfer the color ink applied to the transfer paper.

By the way, in a recording apparatus using a thermal head, the temperature of the thermal head easily affects the recording density. For example, when the ambient temperature is low, the thermal head is in a cold state at the beginning of energization, so that the recording density is lowered. Therefore, it is common to perform the recording operation after heating with a heater or the like to bring the temperature of the entire thermal head to a predetermined temperature equal to or higher than room temperature. This is because by heating the thermal head to room temperature or higher in advance before the recording operation, the recording density at the initial stage of energization and the recording density after recording several sheets can be made the same. Further, the temperature of the thermal head before the initial energization needs to be uniform in the direction of the heating resistor array of the thermal head in the case of a recording apparatus for expressing gradation. Therefore, in the past, in order to equalize the temperature of the thermal head in the direction of the heating resistor array, the thermal head and the support on which the thermal head is mounted are arranged in the direction of the heating resistor array of the thermal head. The thermal head was heated by providing sheet heaters in parallel. Since this sheet-shaped heater can heat the thermal head uniformly in the width direction, a high quality recorded image can be obtained.

[0004]

However, since the sheet-shaped heater is too high in heat insulating property, it is necessary to attach both sides of the sheet-shaped heater in close contact with a material having good thermal conductivity, that is, the thermal head or its support. That is, it may be damaged by self-heating. Particularly in recent years, as the recording apparatus has been downsized, such a space for installing the sheet-like heater has been reduced. Even if it can be installed, since the sheet-like heater has a high heat insulating property, the effect of radiating the heat of the thermal head due to recording to the support side is reduced. Further, the sheet heater has problems such as high cost. Therefore, there is a recording device that heats the thermal head by using a plurality of inexpensive coin-type small heaters instead of the sheet-like heater.
Since the heating resistor array of the thermal head cannot be uniformly heated, it has been a cause of uneven density of the thermal head.

Therefore, the present invention has been made in view of the above points, and provides a recording apparatus in which a plurality of small heaters are used to heat a thermal head uniformly in the width direction thereof. The purpose is to do.

[0006]

According to the present invention, as means for achieving the above object, a thermal head having a heating resistor array in the width direction of a recording paper is mounted on a support, and the thermal head is mounted on the support. In a recording device that performs a recording operation after heating the thermal head to a predetermined temperature using a mounted heating means, the recording device is provided in the support or in the central portion of the thermal head in the width direction of the thermal head. The temperature-measuring element and the heat-generating resistor array on the support at a position most distant from the heat-generating resistor array in the direction orthogonal to the heat-generating resistor array of the thermal head, and centering the temperature-measuring element. An object of the present invention is to provide a recording apparatus having the heating means provided so as to be symmetric with respect to the direction.

Further, according to the present invention, as means for achieving the above object, in the recording apparatus, when the temperature detected by the temperature measuring element is equal to or lower than the predetermined temperature, the recording operation is not started. When permitting and heating the thermal head using the heating means, when the detected temperature reaches a first set temperature higher than the predetermined temperature, the heating of the heating means is stopped and the detection is performed. An object of the present invention is to provide a recording apparatus characterized in that the non-permission of the start of the recording operation is continued until the temperature to be set reaches a second set temperature which is higher than the predetermined temperature and lower than the first set temperature. Is.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an external perspective view of a recording apparatus that is an embodiment of the present invention. In FIG. 1, the recording apparatus 1 has a recording paper storage unit 2 for storing cut recording paper (hereinafter simply referred to as recording paper) fixed to the front of the main body. Among the recording papers stored in the recording paper storage unit 2, only the uppermost recording paper stacked by the separating mechanism described later is separated and fed. The recording paper thus fed is reciprocally moved so that the color inks sequentially applied to the transfer paper are sequentially recorded according to desired recording information, and when the recording operation is completed, the recording paper is ejected from the paper ejection port 19A. The paper is discharged onto the paper discharge tray 19 on the upper part of the storage section 2.

Next, a schematic structure of the inside of the recording apparatus 1 of this embodiment will be described with reference to FIG. FIG. 2 is a diagram showing the internal structure of the recording apparatus 1 which is an embodiment of the present invention. In FIG. 2, the recording apparatus 1 includes a recording paper storage unit 2 for storing a recording paper 2A, a thermal head mechanism unit 10 having a thermal head 12, a platen roller 13, and transfer paper rolls 14A and 14B. Transfer paper 14 wound in the longitudinal direction
And a clamp mechanism section 20 for clamping the front end of the recording paper 2A during the recording operation, and the recording paper storage section 2 for holding the recording paper 2A.
From the platen roller 13 to the platen roller 13 and also discharges the recording paper 2A on the discharge guide plate 32 onto the discharge tray 19, and a paper feed guide plate 31 forming a paper feed path. It has a paper discharge guide plate 32 that is an upper regulating member of the paper feed path and forms a paper discharge path.

The recording paper accommodating portion 2 is provided with a bottom plate 3 whose tip portion 3A is vertically rotatable around a rotation shaft (not shown), and is rotatably provided around the shaft 22A during paper feeding. When the paper feed lever 22 rotates upward, the tip portion 3A of the bottom plate 3 is lifted. In addition, this recording paper storage unit 2
A separation pin lever 7 rotatably attached by a shaft 6, a separation pin 8 for separating the loaded recording paper 2A, and a stopper pin 11 for restricting the separation pin lever 7 downwardly are provided at both ends of the leading end of the separation sheet. A configured separating mechanism unit 30 is provided. The recording paper storage unit 2 is also a space for retracting the recording paper 2A for returning the recording paper 2A to the initial recording position when the recording paper 2A is reciprocated during the recording operation.

Further, the thermal head mechanism section 10 is
The thermal head 12 is rotatably installed around the rotary shaft 10A, and by rotating around the rotary shaft 10A, the thermal head 12 is largely retracted from the platen roller 13 (not shown) and a platen roller. It is possible to move to a set position where it is set at a position opposed to 13. The retracted position of the thermal head mechanism unit 10 is used when exchanging the transfer paper 14 and the like, and the set position is used during recording operation and paper feeding operation. Then, during the recording operation on the recording paper 2A, the heating resistor array 12A (see FIG. 4) of the thermal head 12 is pressed against the recording paper 2A wound around the platen roller 13 via the transfer paper 14. Has become.

The clamp mechanism section 20 is composed of a movable clamp member 20A which is movable around a rotary shaft 21 and a fixed clamp member 20B which is fixed to the recording apparatus 1. The movable clamp member 20A is driven by a drive mechanism (not shown).

Further, the paper feed guide plate 31 is bent into a dogleg from directly below the platen roller 13, and the thermal head 1
It extends to just below 2 and is in contact with the platen roller 13 via an elastic member having one end fixed to it. In this way, the leading end portion of the paper feed guide plate 31 is connected to the platen roller 1.
By making contact with 3, the friction force is applied between the platen roller 13 and the recording paper 2A, and the platen roller 13 can convey the recording paper 2A. The frictional force is set to be smaller than the clamping force of the clamping mechanism section 20.

Next, the thermal head mechanism portion 10 will be described with reference to FIGS. FIG. 3 is a perspective view of a back surface portion of the thermal head mechanism portion. As shown in the figure, the frame structure of the thermal head mechanism unit 10 is roughly composed of left and right aluminum die cast side plates 50 and stays 51 that connect these side plates 50, and the side plates 50 are supported by a shaft 10A. It is rotatably mounted in the recording device 1. That is, the right side plate 50 is rotatably supported by the shaft 10A embedded in the right frame (not shown) of the recording apparatus 1 via a metal bearing press-fitted at one end thereof, and the left side plate 50 is also the same. A shaft 10A implanted at one end thereof is rotatably supported via a metal bearing provided on the left frame of the recording apparatus 1.

Further, as shown in FIG. 4, the back surface of the thermal head 12 is fixed to a heat sink 52 made of an aluminum extruded material through a paste having a good thermal conductivity.
In order to increase the surface area of the heat sink 52, a heat radiating plate 52A is provided in parallel with the heating resistor array 12A of the thermal head 12. The cooling fan 90 (see FIG. 3) mounted on the back surface of the thermal head mechanism 10 blows air from the rear of the thermal head 12 so that the air flows along the radiator plate 52A and is discharged in the left-right direction. Has become.

Further, the thermal head 12 has a temperature measuring element 9 such as a thermistor provided inside the center in the width direction thereof.
The temperature is detected by 2 (see FIG. 2), and air cooling or heating is performed as necessary to keep the temperature at a predetermined level. Further, coin-shaped heaters 91 for heating the thermal head 12 are provided on both left and right sides of the heat sink 52. The coin-shaped heater 91 is provided symmetrically in the width direction of the thermal head 12 with the temperature measuring element 92 as the center, and is provided at a position farthest from the heating resistor array 12A of the thermal head 12. As a result, when the coin-shaped heater 91 generates heat, the position where the temperature measuring element 92 is installed becomes the lowest temperature position in the width direction of the thermal head 12.

By the way, in the case of the coin type heater as described above, the thermal head 12 is compared with the sheet type heater.
Since there is a temperature distribution unevenness in the heat conduction of the above, the heating device eliminates the heating unevenness by controlling the temperature of the thermal head by a controller (not shown). The temperature control of the thermal head will be described below with reference to the flowchart shown in FIG.

The controller first detects the temperature of the thermal head 12 using the temperature measuring element 92 (P1). The detected temperature is an appropriate temperature, that is, the predetermined temperature T or higher T + α
If the following is true, the process proceeds to P6 and waits for a recording operation start signal. In other cases, the start of the recording operation is not permitted and the heating temperature control below P2 or P3 is performed.
If the temperature detected by the temperature measuring element 92 is equal to or lower than the predetermined temperature T, the heater power is turned on to heat the thermal head 12 (P2). Here, the predetermined temperature T is a temperature equal to or higher than room temperature which is preset in the control device as an optimum temperature for initial energization of the thermal head, and the temperature is determined by the structure of the recording device 1, the structure of the heat sink 52, and the like. For example, it is set to 40 ° C. Then, the temperature of the thermal head 12 is detected again by the temperature measuring element 92 while the power source of the heater 91 is kept ON (P3). As a result of this detection,
The temperature of the thermal head 12 is the first set temperature T +
While the temperature is α (for example, 45 ° C.) or lower, the power source of the heater 91 remains ON.

The detected temperature is the above first set temperature T + α.
If it reaches, the power of the heater 91 is turned off (P
4). Here, when the power source of the heater 91 is ON, the thermal head 12 and the heat sink 52 are
The temperature distribution is higher as it is closer to 1, and lower as it is farther from the heater 91. The heater 91 is installed farthest from the heating resistor array 12A of the thermal head 12 and symmetrically with respect to the temperature measuring element 92. Therefore,
The installation position of the temperature measuring element 92 is a place where the temperature is the lowest in the width direction of the thermal head 12 when the heater 91 is powered on, and the temperature detected by the temperature measuring element 92 is the first set temperature T + α. In this case, the temperatures at the left and right ends of the thermal head are above T + α. However, from the state where this temperature unevenness occurs, the heater 91
When the power source is turned off, the heat in the thermal head 12 and the heat sink 52 is radiated and is conducted from the higher temperature to the lower temperature, and eventually the temperature unevenness disappears. The distribution is becoming more uniform. Therefore, the temperature detected by the temperature measuring element 92 when the temperature is made uniform in this way is set to the second set value T + β.
(Β <α), which is preset in the control device. In addition,
The second set value is appropriately determined by the structure of the recording apparatus 1, the installation location of the heater, the positional relationship with the temperature measuring element, etc., including the first set temperature, and the temperature detected by the temperature measuring element 92 is , The second set value T + β, the temperature of the heating resistor 12A of the thermal head 12 is close to the predetermined temperature T. Therefore, the power of the heater 91 is turned off.
Then, the second set temperature T + β (for example, 43 ° C.)
This state is held until (P5) and the recording start signal waits (P6).

On the other hand, if the detection result by the temperature measuring element 92 in P1 is equal to or higher than the first set temperature T + α, the cooling fan 90 is turned on to forcibly cool the thermal head 12 (P7). Then, turn on the power of the cooling fan 90.
With the temperature measuring element 92 kept in the state of
Temperature is detected (P8). As a result of this detection, while the temperature of the thermal head 12 is equal to or higher than the second set temperature T + β, the power supply of the cooling fan 90 is kept in the ON state. When the detected temperature reaches the second set temperature T + β, the cooling fan is turned off (P
9), waiting for a recording start signal (P6). When the recording start signal is input, the recording operation described below is performed.

According to the above temperature control, the small heater 91
Even if the thermal head 12 is heated by using, it is possible to make it uniform in the width direction. As a result, it is possible to obtain a high quality recorded image, and it is particularly effective when used in a recording device that performs gradation expression. According to this temperature control, the thermal head 12 can be made uniform in the width direction even if it is heated by the two small heaters 91 as in the above embodiment. Further, if the heater 91 becomes smaller, the contact area between the thermal head 12 and the heat sink 52 can be maximized, so that the cooling speed of the thermal head 12 becomes faster and the recording apparatus 1 can be made smaller. Further, when the thermal capacities of the thermal head 12 and the heat sink 52 are large, or when the outside air temperature is high, natural cooling takes time. Therefore, as shown by the dotted line in the flowchart of FIG. 5, the power of the heater 91 of P4 is turned off. Right after doing
7, the power of the cooling fan 90 may be turned on to reach the second set temperature T + β.

Next, the operation of the recording apparatus 1 will be described with reference to FIG. In FIG. 2, the thermal head 12 is subjected to the temperature control described above before the paper feeding operation is performed, the temperature is appropriately and uniformly heated, and the above-described waiting state for the recording start signal (P6) is set. ing. When the recording start signal is input to the control device (not shown) from this state,
First, the paper feeding operation is performed. The paper feed lever 22 is rotated upward by a drive mechanism (not shown) to raise the bottom plate 3 of the recording paper storage unit 2. The raising of the bottom plate 3 is performed until the uppermost portion of the loaded recording paper 2A comes into contact with the paper feeding / discharging roller 24. Further, as the bottom plate 3 rises, the uppermost recording paper 2A pushes up the separation pin 8 of the separation mechanism 30. Further, the movable clamp member 20A rotates clockwise around the rotation shaft 21 from the position shown in FIG. 2 and is stopped at a predetermined position. From this state, the paper feeding and discharging roller 2
When 4 rotates counterclockwise, the paper feeding and discharging roller 2
The uppermost recording sheet 2A that is in contact with the sheet 4 is pushed out toward the platen roller 13 side and separated by the separating pin 8. The separated recording paper 2A is conveyed on the paper feed guide plate 31 by the paper feed / discharge rollers 24, and the leading end of the recording paper 2A is attached to the platen roller 13 rotating with the paper feed / discharge rollers 24. When it reaches the abutting position, it is also conveyed by the platen roller 13 due to the pressing force of the paper feed guide plate 31 described above. Then, when it passes through between the thermal heads 12 and reaches the movable clamp member 20A stopped at the above-mentioned predetermined position, a detection device (not shown) installed in the movable clamp member 20A detects it. The rotation operation of the paper feeding / discharging roller 24 and the platen roller 13 is stopped, and the movable clamp member 20A rotates to the clamp position to clamp the leading end of the recording paper 2A.

The leading edge of the recording paper 2A is clamped, and the recording paper 2 between the clamp mechanism portion 20 and the platen roller 13 is clamped.
When the slack of A is removed, the thermal head 12 is brought into pressure contact with the platen roller 13 and the recording operation is performed. This recording operation is performed while slackening the recording paper 2A between the platen roller 13 and the clamper mechanism section 20 as shown in FIG. When the recording of the first color is completed, the slack of the recording paper 2A is removed using the platen roller 13, and the recording operation is similarly performed for the second and subsequent colors. Y, M, C on the transfer paper,
When the B color ink is sequentially recorded and the recording operation is completed, the clamp at the leading end of the recording sheet 2A is released, and the recording sheet 2A is conveyed by the platen roller 13 onto the sheet ejection guide plate 32 which is the sheet ejection path. When the leading end of the recording paper 2A reaches the paper feeding / discharging roller 24, the paper is discharged onto the paper discharging tray 19 by the paper feeding / discharging roller 24 rotating together with the platen roller 13.

When the recording operation is continuously performed, the temperature of the thermal head 12 is controlled and then the above operation is repeated. Further, the temperature detected by the temperature measuring element 92 due to the continuous recording operation is the first set temperature T + α.
When the temperature rises above the above, the recording start operation and the recording operation are stopped.

[0025]

As described above, according to the recording apparatus of the present invention, the support, or the temperature measuring element provided in the central portion of the thermal head in the width direction of the thermal head, and the thermal sensor on the support are used. The heating means provided at a position farthest from the heating resistor array in a direction orthogonal to the heating resistor array of the head and symmetrically arranged in the heating resistor array direction about the temperature measuring element; Therefore, the heating resistor array of the thermal head can be heated substantially uniformly.

When the temperature detected by the temperature measuring element is equal to or lower than the predetermined temperature, the start of the recording operation is prohibited and the thermal head is heated by the heating means to detect the temperature. When the temperature reaches a first set temperature higher than the predetermined temperature, the heating of the heating means is stopped, and the detected temperature is higher than the predetermined temperature and lower than the first set temperature. By continuing the non-permission of the recording operation until the second set temperature is reached, even if the thermal head is heated by using a small heating means, the thermal head can be heated uniformly in the width direction, and high-quality recording can be performed. There is an effect that an image can be obtained.

[Brief description of drawings]

FIG. 1 is an external perspective view of a recording apparatus that is an embodiment of the present invention.

FIG. 2 is a diagram showing an internal configuration of a recording apparatus that is an embodiment of the present invention.

FIG. 3 is a perspective view of a back surface portion of a thermal head mechanism portion in the apparatus of FIG.

FIG. 4 is an exploded perspective view of a thermal head mechanism unit in the apparatus of FIG.

5 is a flowchart showing temperature control of a thermal head in the apparatus of FIG.

[Explanation of symbols]

 1 Recording Device 2 Recording Paper Storage 2A Recording Paper 3 Bottom Plate 7 Separation Pin Lever 8 Separation Pin 10 Separation Pin 10 Thermal Head Mechanism 11 Stopper Pin 12 Thermal Head 12A Heating Resistor Row 13 Platen Roller 14 Transfer Paper 14A, B Transfer Paper Roll 20 Clamping Mechanism Part (clamping means) 20A Movable clamper 20B Fixed clamper 22 Paper feed lever 24 Paper feed / discharge roller 30 Separation mechanism 31 Paper feed guide plate 32 Paper discharge guide plate 50 Side plate 51 Stay 52 Heat sink 52A Radiator 90 Fan 91 Heater (heating means) 92 Temperature measuring element

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B41J 3/20 116

Claims (2)

[Claims] 1. A thermal head having a heating resistor array in the width direction of a recording sheet is mounted on a support, and the thermal head is heated to a predetermined temperature by using a heating means mounted on the support. In a recording apparatus for performing a recording operation after heating a substrate, a temperature measuring element provided in the support or in a central portion in a width direction of the thermal head in the thermal head, and a heating resistor of the thermal head on the support. The heating means is provided at a position farthest from the heating resistor row in a direction orthogonal to the row and symmetrically arranged in the heating resistor row direction about the temperature measuring element. Recording device. 2. The recording apparatus according to claim 1, wherein when the temperature detected by the temperature measuring element is equal to or lower than the predetermined temperature, the start of the recording operation is prohibited and the heating unit is used. The thermal head is heated, and when the detected temperature reaches a first set temperature higher than the predetermined temperature, the heating of the heating means is stopped, and the detected temperature is higher than the predetermined temperature. A recording apparatus, wherein the non-permission of starting the recording operation is continued until a second set temperature lower than the first set temperature is reached.