JPS61202566A - Print system of image forming device - Google Patents

Abstract

PURPOSE:To improve the print quality while keeping the uniformity of each line by designing the number of phase switching of one line feed of a pulse motor to be a print split number of a line or over so as to prevent generation of a discontinuous point at each line or distortion. CONSTITUTION:The number of phase switching of one line feed of the pulse motor 4 is designed to be a split number of one line or ever. For example, a drive circuit 87 is turned on/off in response to a supplied exciting signal to excite each winding in the pulse motor 4 to drive the motor. Further, a head drive circuit 62 drives the heat sensing element group in a thermal head 8 while dividing the group into for blocks in response to a signal outputted from output terminals Q0, Q2, Q4, Q6 of a shift circuit 82. Then the pulse motor 4 is driven by one line's content while being separated into the four stages and each block of the thermal head is driven splittingly attended with each split movement to apply the print for one line. Thus, no discontinuity exists between the print blocks and the uniformity is kept.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a printing method of a thermal transfer type image forming apparatus applied to, for example, output recording of a computer or a word processor.

[Technical Background of the Invention] In recent years, as one of the non-impact printing technologies, thermal transfer type image forming devices that are compact, inexpensive, noiseless, and capable of recording on plain paper (multicolor) have been developed. Printers have been developed and put into practical use.

Normally, this type of thermal printer transfers the ink from the thermal transfer ribbon to the paper by operating the thermal head with paper and a thermal transfer ribbon interposed between the platen and the thermal head (thermal head). It is designed to form an image. In this case, one line is divided into a plurality of blocks and printed in a time-division manner, and the line is fed using a pulse motor, and the phase of the pulse motor is switched for each line.

[Problems in the Background Art] However, in the above-mentioned apparatus, the pulse motor is not yet in operation when printing the first block, and line feeding is performed during printing of the second to third blocks, and the pulse motor is not operated yet when printing the first block. The line feed operation has almost finished during printing.

As a result, discontinuities or distortions occur around the boundary between the second block and the third block for each line, resulting in a disadvantage in that printing quality deteriorates. The relationship between printing positions is such that the above-mentioned discontinuity or distortion always occurs due to differences in the printing time per print or the load on the pulse motor.

Purpose of the Invention This invention was made in view of the above circumstances, and its purpose is to prevent discontinuities or distortions from occurring on each line and maintain uniformity of each line. Therefore, it is an object of the present invention to provide a printing method for an image forming apparatus that can improve printing quality.

[Summary of the Invention 1] In order to achieve the above object, the present invention is such that the number of phase changes for one line feed of the pulse motor is greater than the number of printing divisions of the line.

Embodiment of the Invention] Hereinafter, an embodiment of the invention will be described with reference to the drawings.

1 and 2 show a thermal transfer type image forming apparatus according to the present invention, and numeral 1 in the figures indicates a main body. and,
The main body 1 has a power supply section 2 at the rear and an image forming section 3 at the front, that is, the operation surface side.

The N deep part 2 and the pulse motor 4 etc. provided on the front side thereof are supported by II! 15... are assembled on the main body base 6 to which are attached.

The image forming section 3 is provided with a conductive platen roller 7 approximately at the center of the front part of the main body 1, and generates heat (not shown) below the platen roller 7 along the axial direction of the platen roller 7. A thermal head (print head) 8 is provided as a thermal head having a line head shape. This thermal head 8 has a head mounting base 9
The head mounting base 9 is mounted on a leaf spring 11 whose one end is held by a holder 10, and a coil spring 14 whose lower surface on the free end side is mounted on the plunger 13 of the solenoid 12. is elastically supported by Then, by the excitation/demagnetization operation of the solenoid 12, the thermal head 8 is pressed against the platen roller 7 with a pressure suitable for thermal transfer.
It is designed to be separated by a predetermined distance from the center.

A temperature detector 68 is provided near the thermal head 8 to detect the temperature around the thermal head 8, that is, the temperature of the outside air, and the temperature generated by the heat generated by the thermal head 8. The temperature detector 68 is formed of, for example, a thermistor.

Further, a cassette holder 15 is provided in the main body 1, and this cassette holder 15 has a thermal transfer ribbon (transfer material) 1
6 and the winding core 17 on the feeding side and winding side around which both ends are wound.
．． A ribbon cassette 19 containing 18 is attached. The thermal transfer ribbon 16 is unwound from the unwinding core 17, wound around the first and second ribbon guides 20, 21 in sequence, guided between the platen roller 7 and the thermal head 8, and guided to the first The ribbon is wound around the platen roller 7 by the second ribbon guide 20° 21 and the third ribbon guide 22. The ribbon is then folded back so as to be sharply separated from the platen roller 7 via the third ribbon guide 22 (that is, peeled off from the platen roller 57), and then wound onto the winding-side winding core 18.

Further, a paper mounting section 23 is provided above the power supply section 4, and a roll-shaped paper p wound around a winding core 24 is mounted thereon. Then, the paper p fed out from this mounting section 23
is wound around the paper guide 25 and guided between the platen roller 7 and the thermal transfer ribbon 16, and is wound tightly around the platen roller 7 via a pair of presser rows 526.26. It has become.

Roughly speaking, between the first and second ribbon guides 20 and 21,
A ribbon detector 27 consisting of a light emitting element 27a and a light receiving element 271) for detecting the ink correspondence state of the thermal transfer ribbon 16 is provided.
5 and the presser foot 26 on the upstream side, a static eliminating brush (not shown) and a paper detector 28 consisting of a light emitting element and a light receiving element are provided.

In addition, a display panel 29 is provided on the upper front part of the main body 1, and this display panel 29 includes a power display section 3o, a paper supply display section 31, a ribbon replacement display section 32, and other display sections 33.
is provided.

In addition, 34 is a connector, 35 is a flexible cable,
36 is a knob for manually operating the platen roller 7.

Furthermore, as shown in FIG. 3, the main body 1 is divided into three parts: a lower cover 37, an upper rear cover 38, and an upper front cover 39. The forming portion 3 is divided into two parts and supported by a lower frame 40 and an upper frame 41. And with this,
The lower unit 42 and the upper unit 44 are configured to be freely openable and closable with respect to the lower unit 42 using a pivot shaft 43 of the main body 1 as a pivot point. The upper unit 44 includes a platen roller 7, a paper guide 25, a presser roller 26, 26, a paper detector 28, an operation panel 29, and the like.

The lower unit 43 also incorporates a thermal head 8, a solenoid 12, a ribbon guide 20°21.22, and the like.

Further, the upper unit 44 is always rotated upwardly by a push-up support mechanism 45 made of a torsion spring. It is located in the space between and exposed. That is, the cassette holder 15 is rotatably supported by a pivot shaft 46 on the rotation fulcrum side of the upper frame 41 provided in the upper unit 44, and the range of downward rotation is regulated by a stopper (not shown). The upper unit 44 is configured to rotate only approximately 1/2 of the full opening angle. Therefore, by opening the upper unit 44, the ribbon cassette 19 can be attached to and removed from the cassette holder 15.

Generally speaking, the free end side of the upper unit 44 is usually fixed to the lower unit 42 by a locking mechanism 47 to prevent the upper unit 44 from opening accidentally due to some external force. That is, a hook 48 is rotatably attached to the frontmost portion of the lower frame 40 via a pivot shaft 49, and is rotatably biased by a spring (not shown). Further, a hook hanging bar 50 is provided on the free end side of the upper frame 41. Then, when the upper unit 44 is pushed down against the push-up blade of the push-up support mechanism 45, the hook 4
8 is hooked to a hook hanging bar 50 to hold the upper unit 44 in a closed state. Also, by rotating the hook 48 in the opposite direction, the hook 48 can be rotated in the opposite direction.
8 is removed from the hook retaining bar 50, and the upper unit 44 is automatically opened by the push-up blade of the push-up support mechanism 45.

Further, as shown in FIG. 4, the control 118B60 controls the thermal head 8 through the color conversion unit 61 and the head drive circuit 62 in turn, and the control unit 118B60 to send the paper P and the thermal transfer ribbon 16 through the motor drive unit 63. A pulse motor 4 as a common drive source is connected to each, and the paper detector 28, ribbon detector 27, and display/operation unit 29 are connected to each other.
, an upper unit opening/closing detector 65 is connected, which turns on and off in accordance with the on and off operations of a power switch (not shown). In general, the solenoid 12 is connected through the ribbon changeover switch 67, the temperature sensor 68, and six solenoid drive circuits, and is also connected to an external device 70 such as a computer or word processor through an interface section 71. It becomes.

This device operates when a print command is issued from an external computer, word processor, etc.
It will be printed on paper P.

That is, in response to a print command, the pulse motor 4 is driven to feed the paper P and the thermal transfer ribbon 16 that are in close contact with each other at the same circumferential speed, and the thermal printing (recording) by the thermal head 8 is started. In other words, in this part, the ink on the thermal transfer ribbon 16 is transferred to the thermal head 8.
is heated and melted and transferred to paper P. in this way,
Necessary information is printed on the paper P by transporting the thermal transfer ribbon 16 and the paper P and performing a printing operation by the thermal head 8.

As shown in FIG.
, an OR circuit 85, a phase switching circuit 86, and a drive circuit 87. In other words, the pulse generation circuit 81
generates a reference clock pulse in response to a signal from the control unit 60, and this clock pulse is supplied to the clock input terminal CK of the shift circuit 82. This shift circuit 82 is an 8-dot shift register that receives the output from the OR circuit 85 from the data input terminal and shifts the received data using the supplied clock pulse, and each shift data is transferred to the output terminal. Qo, ~Q7
It is designed to be output from. The shift circuit 82
The signals outputted from the output terminals Qo, Q2, Q4, and Q6 are supplied to the NAND circuit 83 and the head drive circuit 62, and the signals outputted from the output terminals Q1, Q3, Q5, and Q7 are supplied to the NAND circuit 84. It looks like this. The outputs of the NAND circuits 83 and 84 are supplied to the OR circuit 85 and also to the clock input terminal CK of the phase switching circuit 86. The phase switching circuit 86 outputs a phase switching signal every time a clock pulse is supplied in accordance with a signal indicating the rotation direction supplied from the control section 60.

For example, when an up signal is supplied, an excitation signal is output in the order of phase switching signals A, B, A, B every time a clock pulse is supplied, and when a down signal is supplied, a clock pulse is supplied. Phase switching signal B
, A, B, A are output in the order of excitation signals. The drive circuit 87 rotates by exciting each winding within the pulse motor 4 by turning on and off in accordance with the supplied excitation signal.

Further, the head drive circuit 62 divides and drives the thermal element group in the thermal head 8 into, for example, four stages of blocks in accordance with the signals output from the output terminals Qo, Q2, Q4, and Q6 of the shift circuit 82. be.

Next, the operation in such a state will be explained. For example, the shift circuit 82 is now reset by a reset signal from the control section 60. Then, this shift circuit 82
The outputs of IQo-Q7 all become high level,
The outputs of the NAND circuits 83, 845 and the OR circuit 85 all become low level. Therefore, the data input terminal of the shift circuit 82 is also at a low level. Next, the clock pulse CO from the pulse generation circuit 81 is sent to the shift circuit 8.
2's clock input i CK. At this time, the output of the OR circuit 85 is at a low level. As a result, the output terminal Q of the shift circuit 82.

only becomes low level. As a result, the output of the NAND circuit 84 becomes high level, and the phase switching circuit 86 outputs an excitation signal according to the rotation direction. At this time, OR circuit 8
The output of No. 5 also becomes high level.

Next, the next clock pulse C is generated from the pulse generation circuit 81.
1 is supplied to the clock input terminal GK of the shift circuit 82. Then, only the output terminal Q1 of the shift circuit 82 becomes low level. As a result, the output of the NAND circuit 83 becomes high level, and a drive signal is output to the head drive circuit 62. As a result, the head drive circuit 62 drives the thermal head 8 in blocks. next,
The next clock pulse C2 is supplied from the pulse generation circuit 81 to the clock input terminal GK of the shift circuit 82. As a result, only the output terminal Q2 of the shift circuit 82 becomes low level. As a result, the output of the NAND circuit 84 becomes high level, and the phase switching circuit 86 outputs an excitation signal according to the rotation direction. At this time, the output of the OR circuit 85 also becomes high level.

Next, the next clock pulse C is generated from the pulse generation circuit 81.
3 is supplied to the clock input terminal GK of the shift circuit 82. Then, only the output terminal Q3 of the shift circuit 82 becomes low level. As a result, the output of the NAND circuit 83 becomes high level, and a drive signal is output to the head drive circuit 62. As a result, the head drive circuit 62 drives the second block of the thermal head 8 in a divided manner. next,
The next clock pulse C4 is supplied from the pulse generation circuit 81 to the clock input terminal GK of the shift circuit 82. As a result, only the output terminal Q4 of the shift circuit 82 becomes low level. As a result, the output of the NAND circuit 84 becomes high level, and the phase switching circuit 86 outputs an excitation signal according to the rotation direction. At this time, the output of the OR circuit 85 also becomes high level.

Next, the next clock pulse C is generated from the pulse generation circuit 81.
5 is supplied to the clock input terminal CK of the shift circuit 82. Then, only the output terminal Q5 of the shift circuit 82 becomes low level. As a result, the output of the NAND circuit 83 becomes high level, and a drive signal is output to the head drive circuit 62. As a result, the head drive circuit 62 drives the third block of the thermal head 8 in a divided manner. next,
The next clock pulse C6 is supplied from the pulse generation circuit 81 to the clock input terminal CK of the shift circuit 82. As a result, only the output terminal Q6 of the shift circuit 82 becomes low level. As a result, the output of the NAND circuit 84 becomes high level, and the phase switching circuit 86 outputs an excitation signal according to the rotation direction. At this time, the output of the OR circuit 85 also becomes high level.

Next, the next clock pulse C is generated from the pulse generation circuit 81.
7 is supplied to the clock input terminal GK of the shift circuit 82. Then, only the output terminal Q7 of the shift circuit 82 becomes low level. As a result, the output of the NAND circuit 83 becomes high level, and a drive signal is output to the head drive circuit 62. As a result, the head drive circuit 62 drives the fourth block of the thermal head 8 in a divided manner. Incidentally, timing charts for explaining the main parts of the above operation are shown in FIGS. 6(a) to 6(i).

In this way, as shown in FIG. 7(a), the pulse motor 8 rotates (moves) for one line in four stages, and with each divisional movement, as shown in FIG. 7(b), , each block of the thermal head 4 is driven in a divided manner so that one line of printing is performed. Therefore, there is no discontinuity between each printing block, and uniformity can be maintained.

In the above embodiment, the case where one line is divided into four parts is explained, but the invention is not limited to this, and for example, printing can be performed by dividing one line into four parts,
Three-part printing or a variable division method in which the number of divisions is different for each line may be used. Further, the pulse motor phase may be switched for the same number of blocks or more for each line of printing.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to prevent discontinuities or distortions from occurring on each line, and to maintain the uniformity of each line, thereby improving printing quality. It is possible to provide a printing method for an image forming apparatus that can perform the following steps.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is an external perspective view of an image forming apparatus, FIG. 2 is a sectional view showing the internal structure of FIG. 1, and FIG. 3 is a state in which the upper unit is opened. 4 is a block diagram showing the control system, FIG. 5 is a block diagram schematically showing the configuration of the motor drive section, FIG. 6 is a timing chart of main parts for explaining the operation, and FIG. FIG. 7 is a diagram for explaining the operating state of the pulse motor and changes in the printing position. 4...Pulse motor, 8...Thermal head, 16
...Thermal transfer ribbon, 60...Control unit, 61...Color conversion unit, 62...Head drive unit, 63...Motor drive unit, 81...Pulse generation circuit, 82...Shift Circuit, 83.84... NAND circuit, 85... OR circuit, 86... Phase switching circuit, 87... Drive circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 3

Claims (1)

[Claims] In an image forming apparatus that divides one line into a plurality of blocks and prints them in a time-division manner, and uses a pulse motor to feed the line, the number of phase changes for one line feed of the pulse motor is greater than or equal to the number of printing divisions for one line. A printing method for an image forming apparatus characterized by: