JPH05345428A - Heat transfer recording device and facsimile using the same - Google Patents

Abstract

PURPOSE:To protect an ink sheet from sticking to a recording medium and improve the recording picture quality by controlling the impression force of a recording head to the recording medium and the ink sheet based on the timing of recording operation. CONSTITUTION:The impression force of an impression control section 136 to a recording medium of a thermal head and an ink sheet is varied for the period in which recording is carried out to a recording paper by a thermal head 13 and for other periods. The number of black dots in an image data of one line transferred to the thermal head 13 is counted by a black dot number counting circuit 134. Based on the number of black dots, the impression in the periods other than the recording operation is set lower and the impression force for the recording operation is set higher to carry out smooth feeding in the recording period and improve the recording picture quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording apparatus for transferring ink contained in an ink sheet to a recording medium to record an image on the recording medium, and a facsimile apparatus using the apparatus.

[0002]

2. Description of the Related Art Generally, a thermal transfer printer uses an ink sheet in which a heat-melting (thermally subliming) ink is applied to a base film, and a thermal head selectively heats the ink sheet according to an image signal. Image recording is performed by transferring the melted ink to a recording paper. In general, this ink sheet is one in which the ink is completely transferred onto the recording paper by one image recording (so-called one-time sheet), and therefore, the recording length after the recording of one character or one line is completed. It is necessary to convey the ink sheet by the amount corresponding to the above, and surely bring the unused portion of the ink sheet to the position for recording next. For this reason, the amount of ink sheet used increases, and the running cost of the thermal transfer printer tends to be higher than that of an ordinary thermal printer that records on thermal paper.

In order to solve such a problem, a recording paper and an ink sheet are used as disclosed in JP-A-57-83471, JP-A-58-201686 and JP-B-62-58917. There has been proposed a thermal transfer printer in which the sheets are conveyed at different speeds.

[0004]

An ink sheet capable of recording an image a plurality of times (n) (a so-called multi-print sheet).
It is known that when this ink sheet is used, when the recording length L is continuously recorded, the conveyance length of the ink sheet conveyed after the end of each image recording or during the image recording is the length L It is possible to make the recording smaller (L / n: n> 1). As a result, the use efficiency of the ink sheet is n times that of the conventional one, and the running cost of the thermal transfer printer can be expected to be reduced. Hereinafter, this recording method is referred to as multi-print.

In the case of multi-printing using such an ink sheet, the ink in the ink layer of the ink sheet is heated n times. Then, with each heating, a shearing force is generated between the melted ink of the ink layer and the unmelted ink, and the transfer is performed on the recording paper. Therefore, for example, when the time until the recording of the next line becomes longer after the recording of one line and the temperature of the ink decreases, the shearing force between the melted (sublimated) ink and the ink that is not melted (sublimated) is increased. There is a problem that it becomes large and it becomes difficult to separate the ink sheet and the recording paper. This is particularly noticeable when one line of recorded data contains a large amount of black information, and the time interval between the current line and the next line is not constant as in a facsimile machine and the time interval becomes relatively long. This is a problem with such devices. In particular, when the pressure of the platen and the thermal head is high, the recording density is increased, but sticking between the ink sheet and the recording paper is likely to occur.
This causes various obstacles during the recording operation of the next line. In addition, when the pressing force is insufficient, the imbalance of the pressing of the thermal head against the platen easily occurs due to the warp of the thermal head or the like. Due to the occurrence of such an imbalance, there is a drawback that the recording density changes within the width of one line.

The present invention has been made in view of the above problems, and by controlling the pressing force of the recording head against the recording medium and the ink sheet based on the timing of the recording operation, the ink sheet and the recording medium are formed. An object of the present invention is to provide a thermal transfer recording apparatus that prevents sticking and improves recording image quality, and a facsimile apparatus using the apparatus.

[0007]

In order to achieve the above object, a thermal transfer recording apparatus according to the present invention has the following constitution. That is, in a thermal transfer recording apparatus that transfers ink contained in an ink sheet to a recording medium to record an image on the recording medium, an ink sheet conveying unit that conveys the ink sheet and a recording medium conveying unit that conveys the recording medium. Means for recording an image on the recording medium by acting on the ink sheet by a thermal head, and the pressing force of the thermal head on the ink sheet and the recording medium for the recording operation of the recording means. Control means for changing the timing based on the timing.

A facsimile apparatus according to the present invention for achieving the above object has the following configuration. That is,
In a facsimile apparatus having a thermal transfer recording unit that transfers ink contained in an ink sheet to a recording medium to record an image on the recording medium, a receiving unit that receives the image data from an external device and the ink sheet are conveyed. An ink sheet conveying means, a recording medium conveying means for conveying the recording medium, and a recording means for recording an image received by the receiving means on the recording medium by acting on the ink sheet by a thermal head, And a control unit that changes the pressing force of the thermal head against the ink sheet and the recording medium based on the timing of the recording operation of the recording unit.

[0009]

With the above structure, the period during which recording is performed on the recording medium by the recording unit and the period other than that are
The pressing force of the thermal head on the recording medium and the ink sheet can be changed. Here, for example, by setting the pressing force during the recording period to be high and setting the pressing force during the other periods to be low, smooth conveyance during recording and improvement of recording image quality can be achieved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[Description of Facsimile Machine (FIGS. 1 to 4)] FIGS. 1 to 4 are views showing an example in which a thermal transfer printer according to an embodiment of the present invention is applied to a facsimile machine.
1 is a diagram showing an electrical connection between a control unit and a recording unit of the facsimile apparatus, FIG. 2 is a block diagram showing a schematic configuration of the facsimile apparatus, FIG. 3 is a side sectional view of the facsimile apparatus, and FIG.
FIG. 6 is a diagram showing a transport mechanism for a recording paper and an ink sheet.

First, the schematic construction of the facsimile apparatus of this embodiment will be described with reference to FIG.

In FIG. 2, a reading unit 100 photoelectrically reads a document and outputs it as a digital image signal to the control unit 101, and includes a document feeding motor and a CCD image sensor. Next, the configuration of the control unit 101 will be described. A line memory 110 stores the image data of each line of the image data, and the image data for one line from the reading unit 100 is stored when the document is transmitted or copied. When receiving image data, 1-line data of the decoded received image data is stored. Then, the stored data is output to the recording unit 102 to form an image. An encoding / decoding unit 111 encodes image information to be transmitted by MH encoding or the like, and decodes the received encoded image data to convert it into image data. Further, 112 is a buffer memory for storing the coded image data transmitted or received. Each unit of the control unit 101 is controlled by a CPU 113 such as a microprocessor. In addition to the CPU 113, the control unit 101 has a CP
A ROM 114 for storing the control program of U113 and various data, a RAM 115 for temporarily storing various data as a work area of the CPU 113, and the like are provided.

Reference numeral 102 denotes a recording section which has a thermal line head and records an image on a recording sheet by a thermal transfer recording method. This structure will be described later in detail with reference to FIG. 103
Is an operation unit including various function instruction keys for starting transmission, a telephone number input key, and the like, 103a is a switch for instructing the type of ink sheet 14 to be used, and when the switch 103a is on, the multi-print ink sheet is When it is off, it means that a normal ink sheet is attached. Reference numeral 104 denotes a display unit, which is usually provided adjacent to the operation unit 103 and displays various functions and the state of the device. Reference numeral 105 denotes a power supply unit for supplying electric power to the entire device. Also, 106 is a modem (modulator / demodulator), 10
Reference numeral 7 is a network control unit (NCU), and 108 is a telephone.

Next, the structure of the recording unit 102 will be described in detail with reference to FIG. The same parts as those in FIG. 2 are indicated by the same drawing numbers.

In the figure, 10 is a recording paper 1 which is plain paper.
1 is a roll paper obtained by winding 1 around the core 10a.
The roll paper 10 is rotatably accommodated in the apparatus so that the recording paper 11 can be supplied to the thermal head portion 13 by rotating the platen roller 12 in the direction of the arrow. In addition, 10b is a roll paper loading unit, and the roll paper 10 is removably loaded therein. Further, 12 is a platen roller which conveys the recording paper 11 in the direction of the arrow b and presses the ink sheet 14 and the recording paper 11 with the heating element 132 of the thermal head 13. The recording paper 11 on which an image has been recorded by the heat generated by the thermal head 13 is conveyed in the direction of the discharge rollers 16 (16a, 16b) by the further rotation of the platen roller 12, and when the image recording for one page is completed, the cutter 15 (15a). , 15
The page is cut by the mesh of b).

Reference numeral 17 is an ink sheet supply roll around which the ink sheet 14 is wound. Further, reference numeral 18 denotes an ink sheet take-up roll, which is driven by an ink sheet conveying motor described later and takes up the ink sheet 14 in the arrow a direction. The ink sheet take-up roll 17 and the ink sheet take-up roll 18 are removably loaded in the ink sheet loading section 70 in the apparatus body. Further, 19 is a sensor for detecting the remaining amount of the ink sheet 14 and the conveyance speed of the ink sheet 14. Further, 20 is an ink sheet sensor for detecting the presence or absence of the ink sheet 14, 21 is a spring, and the platen roller 12 via the recording paper 11 and the ink sheet 14.
The thermal head 13 is pressed against. Reference numeral 22 is a recording paper sensor for detecting the presence or absence of recording paper.

There are three springs 21 pressed by the thermal head and the platen roller (see FIG. 4). And
The pressing control unit 136 of the thermal head controls the force of each spring. This is set on the spring, the left end spring, the center spring, the right end spring, 0kg, 0.5kg, 1kg,
1.5kg, 2kg, 2.5kg, 3kg, 3.5kg, 4kg,
It can be controlled at 4.5kg and 5kg.

Further, numeral 135 is a reflection type photo sensor, and three of them are set at the left end, the center and the right end. As a result, the recording density of each part can be detected. For example, the left end sensor is mounted 10 cm left from the center, the right end sensor is mounted 10 cm from the center, and the sensor is mounted 5 cm forward from the position of the recording position head and platen.

Next, the structure of the reading unit 100 will be described with reference to FIG.

In the figure, reference numeral 30 denotes a light source for illuminating an original 32, and the light reflected by the original 32 is reflected by an optical system (mirror 50,
51, the lens 52) and input to the CCD sensor 31 and converted into an electric signal. The original 32 is a conveyance roller 53, 5 driven by an original conveyance motor (not shown).
4, 55, and 56, the original 32 is conveyed at a reading speed. Reference numeral 57 denotes a document stacking table, and the plurality of documents 32 stacked on the stacking table 57 are separated one by one by the cooperation of the conveying roller 54 and the pressing separation piece 58, and the reading section 100 is provided. Be transported to.

Reference numeral 41 denotes a control board which constitutes a main part of the control section 101, and various control signals are outputted from the control board 41 to each section of the apparatus. Further, 106 is a modem board unit, and 107 is an NCU board unit.

Further, FIG. 4 is a diagram showing the details of the transport mechanism for the ink sheet 14 and the recording paper 11.

In the figure, reference numeral 24 denotes a platen roller 12 which is rotationally driven to move the recording paper 11 to an arrow b opposite to the arrow a direction.
It is a recording paper transporting motor for transporting the recording paper in any direction. The reference numeral 25 indicates the ink sheet 14 and the capstan roller 7
1, an ink sheet transport motor for transporting in the direction of arrow a by the pinch roller 72. In addition, 26,
Reference numeral 27 is a transmission gear that transmits the rotation of the recording paper transportation motor 24 to the platen roller 12, and 73 and 74 are transmission gears that transmit the rotation of the ink sheet transportation motor 25 to the capstan roller 71. Further, reference numeral 75 is a slip clutch unit.

Here, the ratio of the gears 74 and 75 is set so that the length of the ink sheet 14 wound around the take-up roll 18 by the rotation of the gear 75a becomes longer than the length of the ink sheet conveyed by the capstan roller 71. By setting the above, the ink sheet 14 conveyed by the capstan roller 71 is surely wound up by the winding roll 18. Then, the ink sheet 14 by the take-up roll 18
The slip clutch unit 75 absorbs the amount corresponding to the difference amount between the winding amount of the ink sheet 14 and the difference amount of the ink sheet 14 sent by the capstan roller 71. As a result, it is possible to suppress fluctuations in the transport speed (amount) of the ink sheet 14 due to fluctuations in the winding diameter of the winding roll 18.

FIG. 1 is a diagram showing the electrical connection of the control unit 101 and the recording unit 102 in the facsimile apparatus of the embodiment, and the portions common to the other drawings are designated by the same drawing numbers.

The thermal head 13 is a line head. The thermal head 13 has the following configuration. That is, the shift register 13 that receives the serial recording data 43a for one line and the shift clock 43b from the control unit 101 and stores the recording data for one line, and the shift register 13 by the latch signal 139a.
A latch circuit 131 that latches 0 data and a heating element 132 including a heating resistor for one line are provided. Here, the heating resistors 132 are 132-1 to 132-
It is driven by dividing m blocks indicated by m.

Further, 133 is a temperature sensor, which is attached to the thermal head 13,
Detects the temperature of. Output signal 4 of this temperature sensor 133
2 is A / D converted in the control unit 101 and
13 is input. As a result, the CPU 113 detects the temperature of the thermal head 13 and changes the pulse width of the strobe signal 47 according to the temperature, or changes the driving voltage of the thermal head 13 or the like to determine the characteristics of the ink sheet 14. The energy applied to the thermal head 13 is accordingly changed.

Reference numeral 134 is a black dot number counting circuit for counting the number of black dots in one line. The black dot number counting circuit 134 initializes the value of the counter when a counter clear pulse is generated on the signal line 43c. Then, when the shift clock is generated on the signal line 43b, if the data output to the signal line 43a is black information, the counter value is incremented by one. Then, this count result is always output to the signal line 134a.

When the decoding of one error-free line is completed, the control unit 101 outputs a counter clear pulse to the signal line 43c and then sequentially outputs decoded data to the signal line 43a, and at the same time, outputs a shift clock to the signal line 43b. Output to. After the transfer of the data of one line is completed, the signal line 134
The information output to a is input and the number of black dots of line information to be recorded is recognized. Then, the signal line 44
After outputting the latch pulse to, the recording operation of the current line is started.

Reference numeral 116 is a programmable timer, CP
The time counting time is set from U113, and the time counting is started when the start of the time counting is instructed. Then, it operates so as to output an interrupt signal, a time-out signal, or the like to the CPU 113 at each designated time.

Reference numeral 135 denotes the above-mentioned reflection type photosensor, and the recording density detecting section is constituted by the reflection type photosensors at the left end, the center and the right end. The output of the photo sensor 10 cm left from the center of the recording paper is output to the signal line 135a, and the output of the photo sensor 10 cm right from the center of the recording paper is output to the signal line 135a.
It is output to c. The output of the photo sensor at the center of the recording paper is output to the signal line 135b.

Further, 136 is a pressing control unit of the thermal head, and 136a has 0 kg, 0.5 kg, 1 kg, and 1.5 k.
g, 2kg, 2.5kg, 3kg, 3.5kg, 4kg, 4.5k
The left end spring pressure is controlled by outputting a signal corresponding to g and 5 kg. Similarly, 136b, 136c
Controls the central spring pressure and the rightmost spring pressure.

The type (characteristic) of the ink sheet 14
May be determined by detecting the switch 103a of the operation unit 103 described above, a mark printed on the ink sheet 14, or the like, and a mark, a notch or a protrusion attached to the ink sheet cartridge may be detected. It may be determined and performed.

Reference numeral 46 denotes the thermal head 1 from the control unit 101.
3 is a drive circuit which inputs the drive signal of No. 3 and outputs a strobe signal 47 for driving the thermal head 13 in each block unit. The drive circuit 46 can change the voltage applied to the thermal head 13 by changing the voltage output to the power supply line 45 that supplies a current to the heating element 132 of the thermal head 13 according to an instruction from the control unit 101. Further, the pressing of the thermal head 13 and the platen roller 12 can be controlled by the signal lines 136a, 136b, 136c. Further, the recording densities at the left end, the center, and the right end can be input and controlled from the signal lines 135a, 135b, 135c.

Reference numeral 36 denotes a drive circuit for driving the cutter 15 in mesh with it, which includes a motor for driving the cutter. Three
Reference numeral 9 denotes a paper discharge motor that rotationally drives the paper discharge roller 16. Reference numerals 35, 48, and 49 are driver circuits for rotationally driving the corresponding paper discharge motor 39, recording paper transport motor 24, and ink sheet transport motor 25, respectively. In addition,
The paper discharge motor 39, the recording paper transportation motor 24, and the ink sheet transportation motor 25 are stepping motors in this embodiment, but the invention is not limited to this, and may be a DC motor, for example. ..

[Description of Recording Operation] FIGS. 5 to 7 are flowcharts showing a recording process for one page in the facsimile apparatus of this embodiment. A control program for executing this process is stored in the ROM 114 of the control unit 101. There is.

This process is started when the image data for one line to be recorded is stored in the line memory 110 and the recording operation can be started, and the switch 103a or the like indicates that the multi-ink sheet 14 is mounted. It is assumed that the determination is made by the control unit 101.

In step S1, the black dot number counting circuit 1
Clear the value of 34. Then, in step S2, the print data for one line is serially output to the shift register 130 of the thermal head 13. At this time,
The black dot number counting circuit 134 counts the number of black dots included in one line. When the transfer of the recording data for one line is completed, the latch signal 44 is output in step S3 to latch the recording data for one line in the latch circuit 131.

Next, in step S4, step S
In step 2, the number of black dots for one line transferred to the thermal head is fetched. Specifically, the control unit 101 inputs the value output from the black dot number counting circuit 134 to the signal line 134a, and uses this value as the black dot number counter BLKC.
Store in OUNT.

Next, in step S5, the ink sheet conveying motor 25 is driven to convey the ink sheet 14 by 1 / n lines (more accurately, the conveyance of the ink sheet shown in the timing chart of FIG. 6 which will be described later). As described above, the phase of the ink sheet motor is switched and the ink sheet is conveyed at a timing slightly before the energization of each block).
Further, at this first phase switching timing, the pressing force of the thermal head and the platen is a basic value, and it is important that the pressing force is not increased. As a result, the ink sheet can be conveyed smoothly. Then, in step S6, the recording paper 11 is conveyed by one line (more accurately, like recording paper conveyance shown in the timing chart of FIG. 6 described later, the recording paper is conveyed at a timing slightly before the energization of one block. The motor phase is switched, and the recording paper is transported). Also, at this phase switching timing, the pressing of the thermal head and the platen is a basic value, and it is important that the pressing is not increased. As a result, the recording paper can be conveyed smoothly.

In step S7, the signal line 136
a, 136b, 136c press the thermal head and the platen roller at the left end, the center, and the right end at the basic value +1
Set to kg. That is, the pressure of the thermal head and the platen roller is increased during the recording operation.

The length of one line to be conveyed is set to about 1 / 15.4 mm in the facsimile apparatus of this embodiment, and the conveyance amounts of the recording paper 11 and the ink sheet 14 are respectively the recording paper conveyance. This can be set by changing the number of excitation pulses of the drive motor 24 and the ink sheet transport motor 25.

Next, in step S8, each block of the heating resistor 132 is energized to record an image. Then, in step S9, it is checked whether power supply to all blocks of the thermal head 13 is completed. In step S9, if the energization of all blocks of the thermal head 13 is not completed, the process proceeds to step S10, and if the energization of all blocks of the thermal head 13 is completed, the process proceeds to step S16.

In step S10, it is checked whether or not the generation of print data for the next line has been completed. Then, if the generation of the print data of the next line is completed, the process proceeds to step S11. In step S11, it is judged whether or not it is the first pass after the generation of the data of the next line, and the black dot number counting circuit 134 is cleared at the first pass (step S12). Step S1
In 3, the print data from the next line is sequentially transferred to the shift register 130 of the thermal head 13. Needless to say, at this time, the black dot number counting circuit 134 counts the number of black dots. On the other hand, if the generation of the data of the next line has not been completed, the process proceeds to step S14. In step S14, the encoding / decoding unit 111 of the control unit 101 sequentially decodes the data of the next line to generate data. Then, in step S15, it is checked whether the energization time for one block has elapsed. If the energization time (about 600 μs) has not elapsed, step S10
Then, the above process is repeated. If the energization time has elapsed, the process returns to step S8 to execute the energization process for the next block. In this embodiment, the thermal head 13 is divided into four blocks and is energized and driven, and the time required for recording one line is approximately 2.5 ms (600 μm).
s × 4 blocks).

If the energization of all blocks is completed and the recording of one line is completed in step S9, step S16 is performed.
Proceed to. In step S16, BLKCOUNT
Is 1000 dots or more. When the number of black dots is 1000 dots or more, the sticking force between the ink sheet and the recording paper is strong, so the process proceeds to step S17, and the pressure of the thermal head and the platen roller is set to the basic value -0.5 kg at the left end, the center, and the right end. To do. On the other hand, when the number of black dots is less than 1000 dots, since the sticking force between the ink sheet and the recording paper is weak, the process proceeds to step S18, and the thermal head and the platen roller are pressed at the left end,
Set both center and right end to basic values.

Next, in step S19, it is checked whether the image recording for one page is completed. If the recording of the image for one page is not completed, the process proceeds to step S20. If the recording of the image for one page is completed, the process proceeds to step S26.

In step S20, it is determined whether or not the data transfer of the next line to the shift register 130 of the thermal head 13 is completed. When the data transfer is completed in step S20, the process returns to step S3 and the above process is repeated to record the next line. In addition, the shift register 130 of the thermal head 13
If the data transfer of the next line to is not completed, the process proceeds to step S21.

In step S21, it is checked whether or not the generation of print data for the next line has been completed. And
If the generation of the print data for the next line has not been completed, the process proceeds to step S22, and if the generation of the print data for the next line has been completed, the process proceeds to step S23.

In step S22, the control unit 101
In, the data of the next line is sequentially decoded to generate the data. And it returns to step S21 and repeats the above-mentioned processing.

In step S23, it is judged after the completion of the data generation of the next line whether or not it is the first pass, and if it is the first pass, the process proceeds to step S24 to clear the black dot number counting circuit 134. .. Then, in step S25, all the data for one line is transferred to the shift register 130 of the thermal head 13.

On the other hand, when the image recording for one page is completed in step S19, the process proceeds to step S26 and the recording paper 1
The cutter process 1 is executed. First, in step S26, the recording paper 11 is discharged by a predetermined amount from the discharge rollers 16a and 16b.
Transport in the direction. Then, in step S27, the cutter 1
The recording paper 11 is cut page by page by driving and meshing 5a and 15b. Next, in step S28, the recording paper conveyance motor 24 is reversely driven, and the recording paper 11 is returned by a distance corresponding to the distance between the thermal head 13 and the cutter 15.

FIG. 8 is a timing chart showing the energization timing to the thermal head 13, the ink sheet / recording paper conveyance timing, and the thermal head / platen pressing control in the image recording process of this embodiment. As shown in this timing chart, the thermal head 13
Since the heat generating resistor 132 is divided into four blocks, energization is executed by four strobe signals. Each of the strobes 1 to 4 corresponds to the energization signal of each block of the heating resistor 132 of the thermal head 13. In this embodiment, "moving writing" is adopted, and the recording operation by these strobes 1 to 4 is executed during the conveyance of the recording paper and the ink sheet.

Further, this timing chart shows the recording operation in the super fine mode, and shows that the conveyance of the recording paper and the conveyance of the ink sheet are performed for the phase switching (half step) of the motor when the pulse is generated. Here, the recording paper is 1 / 15.4 in one half step.
Ink sheet is conveyed in 4 half steps of 1 / (1
Carry 5.4 × n) mm. Here, n is 5. still,
Since the ink sheet is conveyed by the winding roll 18, the movement amount per step changes depending on the winding amount. Therefore, the number of driving steps is changed correspondingly.

Timing T1 indicates the timing when the recording data of the next line is completely transferred to the thermal head 13 and the recording of the next line becomes possible. At this point, the pressing of the thermal head by the platen is the basic value. The basic value is an initial value of 1.5 at the left end, center, and right end.
kg. At the timing of T1, the switching of the motor phase between the ink sheet and the recording paper is executed, and the motor is half-step driven. Since the actual recording paper / ink sheet transport operation has a delay after the phase switching, the motor phase switching is executed prior to the recording operation.

Then, recording of one line is started at timing T2, and the pressure of the thermal head 13 and the platen 12 is increased by 1 kg at all points (left end, center, right end). One line is recorded in the period 61. After recording one line, the number of black dots on the recording line is checked in a period 62. Then, since the number of black dots is 950 dots or less than 1000 dots, the pressing control is returned to the basic pressing value. By lowering the pressing value in this period 62, the conveyance of the recording paper and the ink sheet in the next recording period 63 becomes smooth. That is, if the pressure value remains high, the sticking force between the ink sheet and the recording sheet increases, which adversely affects the conveyance of the recording sheet and the ink sheet in the next recording.

Timing T3 shows the time when the recording data of the next line is transferred to the thermal head 13 and the recording of the next line becomes possible. At this time, the motor phases of the ink sheet and the recording paper are switched. Then, in the period 63, the pressing of the thermal head 13 and the platen 12 is set to the basic value +1 kg at the left end, the center, and the right end, and the recording of one line is executed. Then, in the period 64, the number of black dots in this line is 1500 dots, and 1000
Since it is more than dots, thermal head 13 and platen 12
Pressing at the left end, center and right end, basic value -0.5kg
To prevent sticking.

Similarly, the timing T4 shows the time when the recording data of the next line is transferred to the thermal head 13 and the recording of the next line becomes possible. At this time,
Switches the motor phase of ink sheet and recording paper. And
In the period 65, one line is recorded with the pressing value set to the basic value +1 kg at all points. Continuation period 66
Then, the number of black dots in this line is 100 dots, and 1
Since it is 000 dots or less, the pressing of the thermal head 13 and the platen 12 is set to the basic value at the left end, the center, and the right end.

[Description of Recording Principle (FIG. 9)] FIG. 9 is a diagram showing an image recording state when an image is recorded by reversing the conveying directions of the recording paper 11 and the ink sheet 14 in this embodiment. ..

As shown in the figure, the recording paper 11 and the ink sheet 14 are sandwiched between the platen roller 12 and the thermal head 13, and the thermal head 13 is pressed against the platen roller 12 with a predetermined pressure by the spring 12. There is. Here, the recording paper 11 is conveyed at a speed V _P in the direction of arrow b by the rotation of the platen roller 12. On the other hand, the ink sheet 14 is conveyed at a speed V _I in the direction of arrow a by the rotation of the ink sheet conveying motor 25.

Now, the heating resistor 1 of the thermal head 13
When the power is supplied to the power source 105 from the power source 105, the portion of the ink sheet 14 indicated by the hatched portion 91 is heated. Here, 14 a is a base film of the ink sheet 14, and 14 a
Reference numeral b indicates the ink layer of the ink sheet 14. Ink layer 9 heated by energizing heating resistor 132
The ink of No. 1 melts, and the portion indicated by 92 is transferred to the recording paper 11. The transferred ink layer portion 92 corresponds to approximately 1 / n of the ink layer indicated by 91.

At the time of this transfer, it is necessary to generate a shearing force on the ink at the boundary line 93 of the ink layer 14b and transfer only the portion indicated by 92 to the recording paper 11. If the relative speed between the ink sheet 14 and the recording paper 11 is increased,
The ink layer to be transferred can be reliably separated from the ink sheet 14.

[Explanation of Ink Sheet (FIG. 10)] FIG.
Is a cross-sectional view of an ink sheet used for multi-printing of this embodiment, and is composed of four layers here.

First, the second layer is a base film which serves as a support for the ink sheet. In the case of multi-printing, since heat energy is applied to the same place many times, an aromatic polyamide film or capacitor paper having high heat resistance is advantageous, but a conventional polyester film can also be used. In terms of recording quality, it is advantageous in terms of recording quality that these thicknesses are as thin as possible due to the role of the medium.
8 μm is desirable.

The third layer is an ink layer containing an amount of ink capable of being transferred n times onto a recording paper (recording sheet). This component is a resin such as EVA as an adhesive, carbon black or nigrosine dye for coloring, carnauba wax as a binding material, paraffin wax, etc. as a main component and is formulated to withstand n times use at the same place. ing. The coating amount is preferably 4 to 8 g / m @ 2, but the sensitivity and density differ depending on the coating amount, and can be arbitrarily selected.

The fourth layer is a portion on which recording is not performed and the third layer is formed on the recording paper.
It is a top coating layer for preventing pressure transfer of the ink of the layer, and is composed of transparent wax or the like. As a result, only the transparent fourth layer is pressure-transferred, and the background stain of the recording paper can be prevented. The first layer is a heat-resistant coating layer that protects the base film of the second layer from the heat of the thermal head 13. This is suitable for multi-printing in which heat energy for n lines may be applied to the same location (when black information is continuous), but it can be appropriately selected whether or not to use. It is also effective for a base film having a relatively low heat resistance such as a polyester film.

The structure of the ink sheet 14 is not limited to this embodiment, and may be, for example, a base layer and a porous ink holding layer containing ink provided on one side of the base layer. Alternatively, a heat-resistant ink layer having a fine porous network structure may be provided on the base film, and the ink may be contained in the ink layer. Also,
The material of the base film may be, for example, a film or paper made of polyamide, polyethylene, polyester, polyvinyl chloride, triacetyl cellulose, nylon or the like. Further, although the heat resistant coating layer is not absolutely necessary, the material thereof may be, for example, silicone resin, epoxy resin, fluorine resin, ethocellulose or the like.

[Regarding Setting Method of Pressing Reference Value] Next, a test pattern is recorded and the pressing spring force of the thermal head and the platen roller at a plurality of points is automatically adjusted to uniformly press the thermal head and the platen. The setting control of the reference value for setting will be described.

FIG. 11 shows data for setting reference values for pressing the thermal head and the platen at a plurality of points. The initial values for pressing the thermal head and platen are 1.5 kg at the left end, center, and right end.
And Then, a predetermined test pattern is recorded, the recording densities are measured at the left end, the center, and the right end, and at each point, when the voltage is 4 V or higher, that is, when the density is low, +0.5 kg is applied to increase the pressure. When the voltage is 1 V or less, that is, when the density is high, the pressure is reduced by -0.5 kg. The output value of the reflective photosensor for all white information is + 5V.

Next, the setting control of the pressing reference value will be described with reference to the flowchart of FIG. First, in step S31, the pressing force at each of the left end, the center, and the right end is set to the initial value (each 1.5 kg). Then, the test pattern is recorded in steps S32 to S34. In step S32, 2 cm of white information is recorded according to the procedure shown in the flowcharts of FIGS. Similarly, in step S32, 4
The black information of cm and the white information of 3 cm are recorded in step S33. Reflective photo sensor 13 for measuring recording density
Since No. 5 is 5 cm ahead of the recording position of the thermal head 13 and the platen 12, the center of the black information is at the position of the reflective photosensor 135 when the recording of the test pattern is completed in step S34. ..

In step S35, the value of the reflection type photo sensor of the recording density detecting section 135 is input to detect the recording density for each point. Then, step S36
Then, the reference value is set according to the setting data in FIG. 11 (that is, the value increased by +0.5 kg is used as the reference value when the voltage is 4 V or more, and the value added -0.5 kg is used as the reference value when the voltage is 1 V or less. ).

In step S37, step S26 in FIG.
To the control of step S29, that is, the recording paper cutting processing is executed, and this processing is ended.

This adjustment may be performed by a key operation of the operator, or may be performed after recording a predetermined number of sheets. Further, the content of the reference value setting shown in FIG. 11 may be changeable according to, for example, the characteristics of the ink sheet. Further, in the case where the above head pressing adjustment (flowchart in FIG. 12) is repeatedly performed, etc., the initial value setting in step S31 in FIG. 12 is performed by setting the head pressing adjustment value executed before that as the initial value. It may be set.

The pressing force of the platen and the thermal head may be set by the operation section.

In the above embodiment, the front line (1
Paying attention to the number of black dots on the line), the pressure between the head and the platen is controlled at the timing after the recording operation is completed, but the invention is not limited to this. For example, the number of black dots in a plurality of past lines may be focused instead of one line.

Further, in the above-described embodiment, the pressure between the head and the platen is set to be lowered by the same value at the left end, the center and the right end at the timing after the end of the recording operation, but the present invention is not limited to this. , The left edge, the center, and the right edge may have different pressing values to be lowered.

As described above, according to the facsimile apparatus of the present embodiment, the pressure between the thermal head and the platen can be increased at the timing of the recording operation and effective recording can be performed.
Further, after the recording operation, paying attention to the number of black dots of the recording information of the previous line, the larger the number of black dots, the higher the sticking, so that the pressing of the thermal head and the platen can be lowered. Therefore, it is possible to prevent the ink sheet and the recording sheet from sticking to each other after the recording is completed.

Further, it is possible to control the pressure between the head and the platen at a plurality of points by further having recording density detection means at a plurality of points and measuring the recording density at each point of one line. It is possible. As a result, it is possible to increase the pressure between the thermal head and the platen at a point where the recording density is low, and to keep the contact between the thermal head and the platen constant. It is possible to improve the quality.

Although the multi-time sheet is used as the ink sheet in the above-mentioned embodiment, it is needless to say that the same effect can be obtained by using the one-time sheet.

Further, in the above-mentioned embodiment, the so-called "moving writing method" is used in which the recording paper or the like is conveyed during the recording operation.
It is also possible to apply to the "still writing method" in which recording is executed after the end of conveyance, and the same effect is produced.

[0081]

As described above, according to the thermal transfer recording apparatus of the present invention and the facsimile apparatus using the apparatus, the pressing force of the recording head against the recording medium and the ink sheet is controlled based on the timing of the recording operation. This makes it possible to prevent the ink sheet from sticking to the recording medium and to improve the recording image quality.

[0082]

[Brief description of drawings]

FIG. 1 is a diagram showing an electrical connection between a control unit and a recording unit of a facsimile apparatus of this embodiment.

FIG. 2 is a block diagram showing a schematic configuration of a facsimile apparatus of this embodiment.

FIG. 3 is a side sectional view of the facsimile apparatus of this embodiment.

FIG. 4 is a diagram showing a transport mechanism for a recording paper and an ink sheet.

FIG. 5 is a flowchart showing a recording process for one page in the facsimile apparatus of this embodiment.

FIG. 6 is a flowchart showing a recording process for one page in the facsimile apparatus of this embodiment.

FIG. 7 is a flowchart showing a recording process for one page in the facsimile apparatus of this embodiment.

FIG. 8 is a timing chart in the image recording processing operation of the present embodiment.

FIG. 9 is a diagram showing an image recording state when an image is recorded while the recording paper and the ink sheet are conveyed in opposite directions.

FIG. 10 is a diagram showing a cross-sectional view of an ink sheet used for multi-printing.

FIG. 11 is a diagram showing data for setting a reference value for pressing the thermal head and the platen.

FIG. 12 is a flowchart showing a procedure for setting a reference value for pressing.

[Explanation of symbols]

 13 thermal head 101 control unit 130 shift register 131 latch circuit 132 heating resistor 134 black dot number counting circuit 135 recording density detection unit 136 pressing control unit

Claims (7)

[Claims] 1. A thermal transfer recording apparatus for transferring an ink contained in an ink sheet to a recording medium to record an image on the recording medium, and an ink sheet conveying means for conveying the ink sheet, and the recording medium. A recording medium conveying unit, a recording unit that acts on the ink sheet by a thermal head to record an image on the recording medium, and a pressing force of the thermal head on the ink sheet and the recording medium, A thermal transfer recording apparatus comprising: a control unit that changes the recording operation timing based on the timing. 2. The thermal transfer according to claim 1, wherein the control unit increases the pressing force of the thermal head on the ink sheet and the recording medium at the timing of starting the recording operation of one line. Recording device. 3. The measuring means for measuring the number of black dots for one line of a recorded image is further provided, and the control means is based on the number of black dots measured by the measuring means, and the ink sheet and the recording medium. The thermal transfer recording apparatus according to claim 1 or 2, wherein the pressing force of the thermal head to the is changed. 4. The control unit reduces the pressing force of the thermal head on the ink sheet and the recording medium at the timing of ending the recording operation for one line. Thermal transfer recording device. 5. The measuring means for measuring the number of black dots for one line of a recorded image is further provided, and the control means has a greater number of black dots for one line of the recorded image, at a timing after the end of the recording operation. The thermal transfer recording apparatus according to claim 4, wherein the pressing force of the thermal head on the ink sheet and the recording medium is further reduced. 6. A detection unit for detecting recording density at a plurality of points in a line direction of a recorded image, and a pressing force of each point of the thermal head on the recording medium and the ink sheet based on the recording density at each point. 6. The thermal transfer recording apparatus according to claim 1, further comprising a reference value setting unit that sets the reference value of. 7. A facsimile device having a thermal transfer recording means for transferring the ink contained in an ink sheet to a recording medium to record an image on the recording medium, and a receiving means for receiving the image data from an external device, An ink sheet conveying means for conveying the ink sheet; a recording medium conveying means for conveying the recording medium; and a recording of an image received by the receiving means by acting on the ink sheet by a thermal head on the recording medium. A facsimile apparatus, comprising: a recording unit that performs the recording; and a control unit that changes the pressing force of the thermal head on the ink sheet and the recording medium based on the timing of the recording operation of the recording unit.