JPH0444875A - Printer - Google Patents

Abstract

PURPOSE:To enhance the noise frequency of a printing head and allow it to be conducted through a wall to increase an attenuation rate in a high noise level area by providing a constitution where noise from space at the printing head side with a platen acting as a border is allowed to be conducted to an area outside an enclosure and each printing wire is driven in a varying timing manner within a single pitch. CONSTITUTION:If the time when a printing head 1 moves by a single pitch is T, the number of times of printing by pins of each line at a delayed timing by time T/12 is 12. Therefore, no more than two pins are driven simultaneously, even if the maximum number of the pins are used in this invention, while the maximum 24 pins are driven simultaneously in a conventional printing wire system. Thus a printing noise is significantly reduced. If the relationship of frequency between the printing head 1 and a noise pressure is analyzed in terms of 1/3 octave, the noise pressure value when printing is performed is low in the range of 16KHz or lower and high in the range of 16KHz or higher, resulting in a high noise frequency of the printing head 1. The noise of increased frequency due to scattered printing is conducted to an area outside the printer through a wall, so that an efficient noise shielding effect and subsequent significant noise reduction are ensured.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an impact printer.

Conventional technology A conventional printer will be explained below.

FIG. 16 is a cross-sectional view of a conventional printer when using a continuous sheet, and FIG. 17 is a cross-sectional view of the same printer when using a single sheet.
FIG. 18 is a transparent perspective view of the same printer.

In FIGS. 16 to 18, 101 is the upper casing 101.
c and a lower housing 101d; a housing in which an opening 101e is formed in a part of the upper housing; 102 is a carriage 11;
As shown in FIG. 19, the print head mounted on the print head 2 is attached in a so-called staggered arrangement in which the print wires are arranged in two rows and the print wires are alternately arranged. 10
3 is a cylindrical platen; 104 is a tractor feeder that conveys continuous paper to platen 1o3; and 104 is a paper stand that is used horizontally when using Sid continuous paper and vertically when using single sheets. The upper opening 101e of the body 101 is divided into a paper feed port 101a for continuous sheets and a transport port 101b for feeding and discharging single sheets and discharging continuous sheets. 106 is a paper separator located above the platen 102 and divided into a path for insertion into the platen 102 from the transport port 101 and a path for ejection from the platen 102; This is the front cover attached above.

Furthermore, a paper guide 108, a paper press plate 109, a paper holder 110, and a paper press roller 111 are arranged at the rotation of the platen 102 in order to convey the paper smoothly.

The printing operation of the printer configured as described above will be explained below.

First, using FIG. 11, the use of continuous paper will be explained. After the paper is conveyed from the paper conveyance port 101a to the platen 103 by the tractor feeder 104, the paper is conveyed to the printable position by the paper guide 108 and the paper pressing plate 109 in such a manner that it is wrapped around the shear platen 103. From this state, by driving the print wire of the print head 102, an impact force is applied to the paper via an ink ribbon (not shown) to perform printing. Thereafter, while printing is being carried out, the paper is transferred from the paper transport port 101b to the paper separator 10.
It passes above 6 and is discharged.

Next, when using a cut sheet, use it with the paper stand 105 erected as shown in FIG. 12. At this time, the paper is inserted into the paper transport port 101a while being aligned with the upper surface of the paper stand 105. At this time, the inserted paper is inserted into the lower part of the sifting platen 103 by the paper separator 106. After that, when the platen 103 is automatically or manually rotated in the direction indicated by the arrow, the paper follows, but at this time, the paper guide 108 and the paper holding plate 1
09 and is conveyed to the printable position in a manner that it is wrapped around the shim platen 103, and the paper is stamped and discharged in the same manner as when using a continuous sheet.

In addition, the printing wire drive frequency of the above printer is 1157
) (shows a graph showing the relationship between frequency and noise in % octave analysis when z is used. In the figure, e is the measurement result when the front cover 107 is opened, and f in the figure is the measurement result when the front cover 107 is attached. These are the measurement results.

The overall value in these cases was 6.7 dBA when the front cover 107 was open, and 64 dBA when it was attached.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, the printing sound and noise when driving the print head were large.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the present invention has a structure in which the sound from the space on the print head side with the platen as a boundary is transmitted to the outside of the casing through the wall, and each printing wire is placed within one pitch. The structure is such that the motors are driven at different timings.

Function: Due to the above-described configuration of the present invention, the noise frequency of the print head is high υ, and the attenuation rate in the high frequency range is increased due to the noise being transmitted through the wall.

Embodiment FIG. 1 is a cross-sectional view of a continuous paper used in a printer according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the same printer when a single sheet is used, and FIG. 3 is a perspective view of the same printer.

In Figures 1 to 3, 2 is a platen, 3 is a tractor feeder, 4 is a front cover, 5 is a paper guide,
6 is a paper holder, 7 is a paper press plate, 8 is a carriage, 9 is a metal chassis base on which side plates 9a and 9b are formed, 10 is a housing consisting of an upper housing 10a and a lower housing 10b, and 11 is a paper Since the stand has a different power than the conventional technology, the explanation will be omitted. Both ends 12a and 12b of the paper separator 12 extend downward so as to block a cylindrical space created between the small diameter parts 2a and 2b at both ends of the platen 2 and the side plates 9a and 9b. Further, the paper pressing roller 13 is formed so as to be in contact with the entire width of the platen 2. 14 is a roller cover that covers the upper part of the paper pressing roller 13 and whose upper part is pressed against the front cover; 16 is a metal member that blocks the connection between the upper housing 10a and the lower housing 10b and the print head 1; shielding plate, 16
17 is a metal shielding plate attached to the lower surface of the front cover 4; 17 is a soundproof cover having side plates that contact the left and right sides of the paper contacting portion of the paper stand 11; and 18 is a soundproof cover provided on the left and right sides of the paper contacting portion of the paper stand. Lips 19 are lips provided on the left and right sides of the bottom surface of the paper stand. 20
is a cylindrical anti-vibration rubber, and the chassis benuha anti-vibration comb 20
It is attached to the lower housing 1ob via. The print wires 18 to 1x of the print head 1 are arranged in a staggered manner diagonally with respect to the printing direction, as shown in FIG.

The interval between each printing wire is Pxn(n
: natural number), and within the column, each pin is shifted by P/12 with respect to the printing direction. Also, print wires in the same order in each column (for example, print wires 1a and 1m
) are driven at the same timing.

In the printer configured as described above, the shielding plates 9a and 9
b. Separate the space on the printing side and the space behind it with the shim platen 2 as a boundary, and install the paper pressing roller 1o and the roller cover 1.
1, the space between the upper part of the front cover 4 and the front cover 4 is closed off, and the space between the contact area between the upper housing 10a and the lower housing 10b and the print head 1 is closed off using the sound insulation plate 12. Because of this, the airtightness of the space on the print head 1 side is higher than in the past. Therefore, compared to the past, printing sound is less likely to leak outside and noise is reduced.

Consider the difference in soundproofing effect depending on the soundproofing frequency when the airtightness of the print head 1 is increased in this way.

When the airtightness is increased, most of the printing sound is from the housing 10.
Since the print sound is transmitted through some kind of obstacle, such as, the print sound is attenuated by the obstacle.

As shown in FIG. 6, when this is expressed as a transmission loss TL when sound passes through an obstacle with a thickness t, the following formula is obtained.

・TL = L1-L0 = TL2-101oq (0.23 x TL2)...
...(1) o TL 2=20 log(f
) -42L1: Sound pressure before passing the obstacle Lo: Sound pressure after passing the obstacle m: Areal density [K2/Go] f: Frequency [ratio] ρ: Obstacle density (Kp/m) t: Obstacle Thickness [m] As shown in equation (1), the higher the density ρ of obstacles, the larger the transmission loss TL. Also, the density of obstacles ρ is 1.2
8 X 10 [K9/rI? ), frequency 20~2
The change in transmission loss up to oooo()k) is measured when the obstacle thickness t is 1X10. 3X10. 6X10-8 [m]
The graph of frequency f and transmission loss TL in each case is shown in FIG. As shown in FIG. 6, it can be seen that the transmission loss increases as the frequency increases, regardless of the thickness of the obstacle.

Next, driving of the print wires 18 to 11 of the print head 1 will be explained using an example of so-called black solid printing in which all the print wires are driven for each pitch.

If the time it takes for the print head 1 to move one pitch is T, then
By performing printing 12 times with the pins on each side shifting the timing by a time of T/12, the same printing results as in the prior art are obtained. For this reason, whereas conventionally a maximum of 24 pins of the printing wire are driven at the same time, in this embodiment, at most two or more pins are not driven at the same time, so the printing noise is significantly reduced.

Here, if the vibration frequency of the conventional print head during black peta printing is f(-1/T), then in the case of this embodiment, the driving frequency of each pin is f, but during one pitch 12
Since the print head 21 is driven twice, the vibration frequency of the print head 21 is f×
12, the vibration frequency is higher than before. In this embodiment, the printing wire is driven a plurality of times for each pitch, not just for black petals, so the vibration frequency of the print head becomes high throughout printing. Graphs of the results of % octave analysis of the relationship between sound pressure and frequency between the conventional print head and the print head of this embodiment are shown in C and d of FIG. 7, respectively. The conditions for this analysis are as follows.

O pin arrangement condition Character pitch: P = 1/120" Number of bins in one row: m = 12 Number of pitches between rows: n = 3 (n = 1.2.3) Pitch between rows: P L = P * n = 1 /40" Pitch between pins: P p = 1 /m = 1 /1440"・
Pin drive condition frequency: f = 1157 (±) Period: T = 1 / f = 864 Cμs] O printing pattern Numbers, alphabets mixed characters As shown in this analysis, the sound pressure value during printing in this example is Compared to the past, the frequency below 16 KHz is smaller, and 16 KHz
The above is getting bigger. That is, by configuring the print head 1 as in this embodiment, the noise frequency of the print head increases.

In summary, with the configuration of this embodiment, the noise whose frequency has increased due to distributed printing is transmitted to the outside through the wall, so it is efficiently shielded and the noise can be significantly reduced.

FIG. 8 shows a graph of the % octave analysis results of the present embodiment when the front cover 4 is opened and when the front cover 4 is attached. Even when compared with the conventional printer shown in FIG. 20, it can be seen that the soundproofing effect has been improved by covering the circumference υ of the carriage shaft with a metal plate. The soundproofing effect is especially great in the high-frequency range, and the dispersed printing effectively blocks the printing sound, which has shifted to a higher frequency than before. Also, the overall noise value is e 2 dBA when the front cover is open.

It can be seen that the soundproofing effect is 4sdBA when installed and 45dBA when installed, which is much higher than before.

Incidentally, FIG. 9 shows an example of a print head control device for operating the print head shown in this embodiment as shown in this embodiment.

In FIG. 9, 51 is a central processing unit (hereinafter abbreviated as CPU), 62 is an input/output unit (hereinafter abbreviated as T10 unit) having an ink face between each device, and 53 is a character font reading unit. Dedicated memory (hereinafter referred to as character phono) R
It is abbreviated as OM. ).

64 is an oscillator, and 66 is an address counter, which is driven by the basic clock C generated from the oscillator 4. 66 is a magnitude comparator and print mode data f for switching the character quality from CPU 1 and 7 drain counter 6
6 and outputs a counterload signal q to the address counter 66. 67 is a distributed timing read-only memory (hereinafter abbreviated as distributed timing ROM) in which distributed timing is written, and the output e of the address counter 65 and print mode data h for switching character quality from the CPU 51 are used as addresses and distributed. The timing is read out. 8 is a latch unit that latches the output 51 of the distributed timing ROM 57 which is composed of flip-flops, 69 is an address power, and output el of the counter 66.
, e2 to output a latch clock J to the latch unit 58, and constitutes a distributed timing generation unit 60 that generates timing for distributing print data from these.

61, 62, and 63 are data m1 and data m1, respectively, which are obtained by delaying the print data m○ from the CPU 1 by one data period corresponding to one dot row by the output e3 of the address counter 65.
Data m2 is delayed by one data period, and data m2 is delayed by one data period.
A launch section 64 is comprised of a flip-flop that outputs data m1 delayed by a data period.
A data selector 65 selects data m2 and m3 in response to a select signal n from the CPU 51.

and a latch section consisting of a flip-flop that uses the output 0 of the data selector 64 as input data and the output ■ of the distributed timing generation section as a latch clock, and 66 is the output 1 of the distributed timing generation section 60 and the output p of the latch section 66. The FIFO unit 67 is constituted by an AND circuit that performs an AND operation with the head drive signal q and outputs the head drive signal q.

Reference numeral 68 denotes a head driver which drives a driver 69 based on the output of the latch section and the output q of the AND circuit.

FIG. 10a is a circuit diagram for one bin of the head driver 68,
FIG. 10 is a timing chart of signals for driving the head driver 68. In FIG. 10a, transistors 71 and 72 and a diode T3 are connected to both ends of the head coil 70.
6 collector. The emitter of transistor 72 is grounded.

The operation of the print head control device configured as above will be described below. Note that the pattern of the print head 1 is as described above, so a description thereof will be omitted.

In order to facilitate control of the 12 pins in the same row of printing wires, the lower 8 pins are designated as an L block, and the upper 4 pins are designated as an H block.

FIG. 11a is a timing chart showing the timing for 24 pins of the output signal of the distributed timing generator 6Q;
FIG. 4 shows the output signal l of the distributed timing generator eo.
It is a timing chart showing the timing for 4 pins. T1 is the basic cycle for printing one dot, T2 is the ON time of this transistor 21 in Fig. 3, and T3 is the period a in Fig. 3.
is the ON time of the transistor 22. A total of 24 types of basic cycle signals corresponding to each of these pins and transistors are written in advance in the distributed timing ROM 57, and are read out at the address generated by the address counter 65.

FIG. 12 is an address map of the distributed timing ROM 57. The printer's character font is draft and N L
There are two types of Q (Nea, r Letter Quality), and the number of letters in inches is 10.12.15.1
4 types of 7 cpi, print direction of head is forward direction (hereinafter referred to as
It is abbreviated as Go. ) and reverse direction (hereinafter abbreviated as RETURN).

Distributed timing data is written in hexadecimal numbers every 1000 addresses, up to a total of FFFF addresses.

These print mode selections are made by mode data signals. Although the length of T1 in FIG. 11 is i for each print mode, the magnitude comparator 56 loads the address counter 56 to all zeros after T1 time according to each print mode.

T1 is set to a maximum of 1024 μ'S.

FIG. 13 is a timing chart showing the output latch timing of the distributed timing ROM 57. address e
The switching time T4 is T4-250 n S te, 1
Distributed timing ROM by address e in a period of μs
Data of the lower 8 bits of the signal that turns on transistor 72 from 5γ (hereinafter abbreviated as CL data), data of the lower 8 bits of the signal that turns on transistor 1 (hereinafter abbreviated as PL data), transistor The data of the upper 4 bits of the signal that turns on transistor 72 (hereinafter abbreviated as PL data), the data of the upper 4 bits of the signal that turns on transistor stuff 1 (hereinafter abbreviated as PL data), are sequentially 8 Powered. T5 is the Hatake delay time of the distributed timing ROM67, which is about 160 nS, so CL, PL
, CH, PH data is latched timing T6 is T5
(T6 = 200 nS so that T6 (T4).

These latch clocks f1 p j2. T3. j4 is el output from the address counter 55 in the shift register 2, 59.

It is created from θ2. In the latch section 68, the distributed timing R
CL data, PL data, CH data, and PH data of output i of OM5 are latched clock j1゜j2+ i3+
By latching them by j4 and further latching them at the rising edge of 01, 1 is generated in each 12-bit distributed timing signal. These outputs are accurate to 1 μs.

FIG. 14 is a timing chart of the FIFO section. Character printing modes are draft/NLQ, 10, 12
, 15, and 1γcpi. Among these types, for example, as shown in FIG.
There is one that is 7432 inches.

By the way, since the dot pattern spacing of the head is 1/120 inch, the dispersion timing for dividing 1/120 inch into 12 is such that the print dot spacing from the CPU 51 is 1/432.
It spans four data of inch print data mo. In order to support these printing modes, first the data
1 data each such as ml, m2゜m3,
The data delayed by 2 data and 3 data periods is input to the data selector 64, and the select signal n from the CPU 51 is inputted to the data selector 64.
Data selected by. Try to get the following.

In the case of FIG. 14, pins 1 to 8. Pins 9-14. pin 16
~20. Each print data of pins 21 to 24 is mo
, ml, m2, and m3.

Here, if the print data interval is fixed at 1/120 inch, this data selector 64 and the flip-flop group 61
, 62.63 are not necessary. mo and the output of the data selector 64, the print data of each of the 64 pins input to the latch section 65 is latched by the distributed timing signal shown in FIG. Furthermore, the 24-bit latched data p of each pin and the distributed timing signal 1 are ANDed.
By using an AND circuit 66, a signal drive signal q is obtained.

In addition, in the head driver 68 by the drive signal q, as shown in FIG. 10, first, when both q are set high, the transistors 71 and 72 are turned on, and the current I flows through the terminal coil 70 and rises according to the time constant. Next, when k is set to low, 71 is turned off and current flows from the diode 73 to the head coil 7°. Then lower q
The current gradually decreases to zero. Wire dot printers that are driven by electromagnetic force have a two-stage drive that switches both ends of the head coil in order to drive the wire at high speed and with low power consumption. Driven.

In this embodiment, the printing wires are arranged in two parallel rows, but they may be arranged in a diamond shape as shown in FIG. 16.

Effects of the Invention The present invention has a structure in which sound from the space on the print head side with the platen as a boundary is transmitted to the outside of the casing through the wall, and a driving means for driving each print wire of the print head at different timings within one pitch printing. Since the printing wire is driven by the driving means, the printing sound becomes high-pitched, and the airtight means increases the soundproofing effect in the higher range, so it is possible to effectively block the printing sound and reduce the noise. I can do things.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the present invention when continuous paper is used, Fig. 2 is a cross-sectional view of the same printer when a single sheet is used, Fig. 3 is a perspective view of the same printer, and Fig. 4 is a diagram of the printing wire of the same printer. Arrangement diagram, Figure 6 is an explanatory diagram of the relationship between obstacles and sound transmission, Figure 6 is a graph showing the relationship between transmission loss and frequency, and Figure 7 is a diagram of the print head of the same printer and a conventional printer. A graph of % octave analysis of the print sound. Figure 8 is a graph of the % octave when the front cover 107 of the same printer is removed and installed. Figure 9 is a graph of the print wire drive control section of the same printer. 10 is a circuit diagram for one bin of the head driver of the same control means, FIG. 11 is a timing chart showing the timing of the output signal from the distributed timing generation section 6o of the same control means, and FIG. 12 is the same. FIG. 13 is a time chart showing the output latch timing of the distributed timing ROM 57 of the control means, FIG. 14 is a timing chart of the FIFO section of the control means, and FIG. 15 is an address map diagram of the distributed timing ROM 67 of the control means. FIG. 16 is a cross-sectional view of the printer according to the prior art when the printer is used for continuous sheets, FIG. 17 is a cross-sectional view of the same printer when it is used for single sheets, and FIG. 18 is the same FIG. 19 is a perspective view of the printer, FIG. 19 is an arrangement diagram of the print wires of the print head of the same printer, and FIG. 20 is a percentage octave analysis result club of the same printer when the front cover is opened and when it is installed. 1... Print head, 2... Platen,
4...Front cover 6...Paper guide, End...Paper holding plate, 9...
Chassis vane, 10... Housing, 11...
... Paper stand, 12 ... Paper separator, 13 ... Paper holding roller, 14 ...
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°'' ---Fig. 12 Fig. 13 k (tz 1t) f! uzbIt) T=====Go== T=Two===■=D Fig. 14/7 IB bin 19.2θ bin 1'-1-f r1 Goshi Bunbai pitch P2'/rz. Castle Figure 19

Claims (1)

[Claims] It has a carriage that is reciprocably supported by a carriage shaft, a print head that is attached to the carriage and performs printing by driving a plurality of printing wires and applying an impact force to the paper, and a shaft that protrudes from both ends. , a platen that supports the paper from the back side of the print head, a base member that has a pair of side plates that support protrusions of shafts at both ends of the platen and supports the carriage shaft, and an end that is in contact with the base member. an upper cover that covers the carriage shaft, the carriage, the print head, and the platen; a paper transport port formed in a part of the upper cover; and a paper feed side of the platen located above the platen. a paper separator that separates the print head from the print head of the platen, a paper press plate that contacts the entire width below the print head of the platen, and a paper press roller that is pressed above the print head of the platen, and A printer having a structure in which sound from a space on the print head side is transmitted to the outside of the housing through a wall, and each print wire of the print head is driven at different timings within one pitch printing.