JPS63194961A - Driving device for printing head heat generating element - Google Patents

Driving device for printing head heat generating element

Info

Publication number
JPS63194961A
JPS63194961A JP2917087A JP2917087A JPS63194961A JP S63194961 A JPS63194961 A JP S63194961A JP 2917087 A JP2917087 A JP 2917087A JP 2917087 A JP2917087 A JP 2917087A JP S63194961 A JPS63194961 A JP S63194961A
Authority
JP
Japan
Prior art keywords
reference signal
constant current
setting means
output
level setting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2917087A
Other languages
Japanese (ja)
Inventor
Kiyoaki Nishikawa
西川　潔明
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP2917087A priority Critical patent/JPS63194961A/en
Publication of JPS63194961A publication Critical patent/JPS63194961A/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
    • B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
    • B41J2/35—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads providing current or voltage to the thermal head
    • B41J2/355—Control circuits for heating-element selection
    • B41J2/36—Print density control
    • B41J2/365—Print density control by compensation for variation in temperature

Abstract

PURPOSE:To sufficiently compensate for variations of thermal temperature generated in response to a difference in the resistance value of a heat generating element by providing a reference signal level setting means capable of arbitrarily setting an output level of a reference signal which is output by the reference signal output circuit along with the reference signal output circuit. CONSTITUTION:A reference signal level setting means 6 forms a voltage dividing a circuit to zener diode 54B with a resistor 55. For this reason, a constant voltage output by the zener diode 54B is divided by both resistor 55 and reference signal level setting means 6. Then a mid-point of the voltage dividing circuit, i.e. a potential applied to the reference signal level setting means 6 is entered to a positive terminal of an operating amplifier 53. A constant current value running through an output transistor 52 is varied by varying a variable resistor of the reference signal level setting means 6. This variation of a constant current causes a variation of potential drop in a resistor 42 to which the constant current is applied (variation of the potential Vs). As a result, the value of the constant current applied to a plurality of heat generating elements 1A is controlled so that it may easily rise or come down.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、印字ヘッド発熱体駆動装置に係り、とくにイ
ンクリボンを珀いた熱転写型プリンタにおける印字ヘッ
ド発熱体駆動装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a print head heating element driving device, and more particularly to a print head heating element driving device in a thermal transfer printer that includes an ink ribbon.

〔従来の技術〕[Conventional technology]

第２図に従来例を示す。この第２図の従来例では、印字
ヘッド（図示せず）に装備されている複数の発熱体素子
ＩＡψ各々に対し、同一に形成された発熱体駆動回路９
０が各別に併設されている。FIG. 2 shows a conventional example. In the conventional example shown in FIG. 2, a heating element driving circuit 9 is formed identically for each of a plurality of heating element elements IAψ installed in a print head (not shown).
0 are provided separately for each.

この発熱体駆動回路９０は、発熱体素子ＩＡを必要に応
じて電源回路９１に４通せしめるスイッチングトランジ
スタ９２と、このスイッチングトランジスタ９２のベー
ス端子とアースとの間に設けられた作動スイッチ部９３
と、ベース端子に一定レベルの所定の定電流を印加する
抵抗９４とにより構成されている。そして、作動スイッ
チ部９３のオン（ＯＮ）、オフ（ＯＦＦ）により、各発
熱体素子ＩＡがスイッチングトランジスタ９２を介して
定電流駆動されるようになっている。This heating element drive circuit 90 includes a switching transistor 92 that allows four heating element elements IA to pass through a power supply circuit 91 as necessary, and an operation switch section 93 provided between the base terminal of this switching transistor 92 and the ground.
and a resistor 94 that applies a predetermined constant current at a constant level to the base terminal. Each heating element IA is driven with a constant current via the switching transistor 92 by turning the operation switch section 93 on and off.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

しかしながら、上記従来例においては、電源電圧の変動
によって発熱体素子ＩＡに通電される電流値が変化する
という不都合が生じている。また、各発熱体素子ＩＡの
電気抵抗がすべて同一とは限らないことから僅かな抵抗
値の差が発熱温度のバラツキとなって表われ、これがた
め、例えば周囲温度が低い場合等においては、鮮明な熱
転写を行うことができないという不都合が生じていた。However, in the conventional example described above, a problem arises in that the value of the current applied to the heating element IA changes due to fluctuations in the power supply voltage. In addition, since the electrical resistance of each heating element IA is not necessarily the same, a slight difference in resistance value will appear as a dispersion in the heat generation temperature. Therefore, for example, when the ambient temperature is low, This has caused the inconvenience that thermal transfer cannot be performed.

〔発明の目的〕[Purpose of the invention]

本発明は、かかる従来例の有する不都合を改善し、とく
に、発熱体素子に印加する定電流のレベルを必要に応じ
て任意に変えることができ、これによって発熱体素子の
抵抗値の差に伴う発熱温度の変化を充分に補償すること
のできる印字へラド発熱体駆動装置を提供することを、
その目的とする。The present invention improves the disadvantages of the conventional example, and in particular, it is possible to arbitrarily change the level of the constant current applied to the heating element as necessary, and thereby It is an object of the present invention to provide a heating element driving device for printing that can sufficiently compensate for changes in heating temperature.
That purpose.

〔問題点を解決するための手段〕[Means for solving problems]

本発明では、発熱体素子に定電流を印加する定電流出力
回路と、この定電流出力回路の出力電流値を一定値に制
御する定電流制御手段と、この定電流制御手段用の基準
信号を出力する基準信号出力回路とを備えている。さら
に、基準信号出力回路が出力する基準信号の出力レベル
を必要に応じて任意に設定し得る基準信号レベル設定手
段を、基準信号出力回路に併設するという構成を採って
いる。これによって前記目的を達成しようとするもので
ある。The present invention includes a constant current output circuit that applies a constant current to a heating element, a constant current control means that controls the output current value of the constant current output circuit to a constant value, and a reference signal for the constant current control means. and a reference signal output circuit for outputting the reference signal. Further, the reference signal output circuit is provided with a reference signal level setting means that can arbitrarily set the output level of the reference signal output by the reference signal output circuit as necessary. This aims to achieve the above objective.

〔発明の実施例〕[Embodiments of the invention]

以下、本発明の一実施例を第１図に基づいて説明する。 An embodiment of the present invention will be described below with reference to FIG.

ここで、前述した従来例と同一の構成部材については同
一の符号を用いるものとする。Here, the same reference numerals are used for the same constituent members as in the conventional example described above.

第１図において、複数の発熱体素子ＩＡ、ＩＡ。In FIG. 1, a plurality of heating element elements IA, IA.

・・・は、熱転写型プリンタの印字ヘッド（図示せず）
に装備されている。各発熱体素子ＩＡには、定電流出力
回路２と、この定電流出力回路２をオン（ＯＮ）又はオ
フ（ＯＦＦ）せしめるスイッチ手段３とが併設されてい
る。各定電流出力回路２には、この定電流出力回路２の
出力電流値を一定値に制御する定電流制御手段４と、こ
の定電流制御手段４における演算用の基準信号を出力す
る基準信号出力回路５とが併設されている。そして、基
準信号出力回路５には、その出力である基準信号の出力
レベルを必要に応じて外部から任意に設定することので
きる基準信号レベル設定手段６が併設されている。... is the print head of a thermal transfer printer (not shown)
is equipped with. Each heating element IA is provided with a constant current output circuit 2 and a switch means 3 for turning the constant current output circuit 2 on or off. Each constant current output circuit 2 includes a constant current control means 4 that controls the output current value of this constant current output circuit 2 to a constant value, and a reference signal output that outputs a reference signal for calculation in this constant current control means 4. A circuit 5 is also provided. The reference signal output circuit 5 is also provided with a reference signal level setting means 6 that can arbitrarily set the output level of the reference signal outputted from the reference signal output circuit 5 from the outside as required.

定電流出力回路２は、第１図に示す如く発熱体素子ＩＡ
に直列接続された抵抗２１及びスイッチングトランジス
タ２２の直列回路と、スイッチングトランジスタ２２の
ベース側に接続されたダイオード２３とにより構成され
ている。スイッチングトランジスタ２２は、エミッタ端
子が抵抗２１を介してＶ　（Ｖ）の電源回路９１に接続
され、コレクタ端子が発熱体素子ＩＡを介してアースさ
れている。The constant current output circuit 2 includes a heating element IA as shown in FIG.
The circuit includes a resistor 21 and a switching transistor 22 connected in series, and a diode 23 connected to the base side of the switching transistor 22. The switching transistor 22 has an emitter terminal connected to a V 2 (V) power supply circuit 91 via a resistor 21, and a collector terminal grounded via a heating element IA.

スイッチ手段３は、抵抗３１とスイッチ素子３２とによ
り構成され、スイッチングトランジスタ２２のベース端
子とアースとの間に接続されている。スイッチ素子３２
は、図示しない印字制御手段に制御されて作動するよう
になっている。The switch means 3 includes a resistor 31 and a switch element 32, and is connected between the base terminal of the switching transistor 22 and ground. Switch element 32
is operated under the control of a printing control means (not shown).

定電流制御手段４は、演算増幅器４１と、この演算増幅
器４１のプラス端子と電源回路９１との間に接続された
抵抗４２とを備えている。The constant current control means 4 includes an operational amplifier 41 and a resistor 42 connected between the positive terminal of the operational amplifier 41 and the power supply circuit 91.

演算増幅器４１の′マイナス端子には、当該演算増幅器
４１の出力信号が入力されるようになっている。この演
算増幅器４１は、そのプラス端子に入力される端子電圧
■、を基準信号電圧とするバッファ機能を備えている。The output signal of the operational amplifier 41 is input to the negative terminal of the operational amplifier 41. This operational amplifier 41 has a buffer function that uses the terminal voltage (2) inputted to its positive terminal as a reference signal voltage.

発熱体素子ＩＡに印加される定電流値は、スイッチング
トランジスタ２２のベース・エミッタ間の電圧降下とダ
イオード２３の電圧降下とを同一とすると、前述した演
算増幅器４１のプラス端子に入力される端子電圧Ｖ３を
定電流出力回路２の抵抗２１の抵抗値で除算した値とな
る。このため、この端子電圧Ｖ、は、各発熱体素子ＩＡ
に印加される定電流値を決定する作用を成す。The constant current value applied to the heating element IA is equal to the terminal voltage input to the positive terminal of the operational amplifier 41 mentioned above, assuming that the voltage drop between the base and emitter of the switching transistor 22 and the voltage drop of the diode 23 are the same. The value is obtained by dividing V3 by the resistance value of the resistor 21 of the constant current output circuit 2. Therefore, this terminal voltage V, for each heating element IA
The function is to determine the constant current value applied to the

基準信号出力回路５は、第１図に示す如く抵抗５１を介
してエミッタ接地された出力トランジスタ５２と、この
出力トランジスタ５２のベース端子に所定レベルの作動
信号を出力する演算増幅器５３と、この演算増幅器５３
のプラス端子の入力レベルを特定する定電圧回路５４と
を備えている。The reference signal output circuit 5 includes an output transistor 52 whose emitter is grounded via a resistor 51 as shown in FIG. Amplifier 53
and a constant voltage circuit 54 that specifies the input level of the positive terminal of.

この内、定電圧回路５４は、図に示す如く電源回路９１
側に接続された抵抗５４Ａと、アース側に接続され定電
圧出力を維持するツェナーダイオード５４Ｂとの直列回
路により構成されている。Among them, the constant voltage circuit 54 is connected to the power supply circuit 91 as shown in the figure.
It is constituted by a series circuit of a resistor 54A connected to the side and a Zener diode 54B connected to the ground side to maintain a constant voltage output.

そして、その中点の電位Ｖ０が抵抗５５を介して演算増
幅器５３のプラス端子に入力されるようになっている。Then, the potential V0 at the midpoint is inputted to the positive terminal of the operational amplifier 53 via the resistor 55.

この演算増幅器５３のマイナス端子には、この演算増幅
器５３の出力側に装備された出力トランジスタ５２のエ
ミンタ端子の電位が入力されるようになっている。また
出力トランジスタ５２のコレクタ端子は、前述した定電
流制御手段４における演算増幅器４１のプラス端子（電
位ＶＳ）に接続されている。The potential of the emitter terminal of the output transistor 52 provided on the output side of the operational amplifier 53 is input to the negative terminal of the operational amplifier 53. Further, the collector terminal of the output transistor 52 is connected to the plus terminal (potential VS) of the operational amplifier 41 in the constant current control means 4 described above.

基準信号レベル設定手段６としては、第１図に示す如く
外部操作可能な可変抵抗が用いられている。この基準信
号レベル設定手段６は、演算増幅器５３のプラス端子と
アースとの間に装備されている。この基準信号レベル設
定手段６は、抵抗５５とともに前述したツェナーダイオ
ード５４Ｂに対して分圧回路を形成している。このため
、ツェナーダイオード５４Ｂによる定電圧出力は、抵抗
５５と基準信号レベル設定手段６とによって分圧される
。そして、この分圧回路の中点すなわち基準信号レベル
設定手段６に印加される電位が演算増幅器５３のプラス
端子に入力されるようになっている。As the reference signal level setting means 6, an externally operable variable resistor is used as shown in FIG. This reference signal level setting means 6 is provided between the positive terminal of the operational amplifier 53 and the ground. This reference signal level setting means 6 forms a voltage dividing circuit with the resistor 55 for the Zener diode 54B described above. Therefore, the constant voltage output from the Zener diode 54B is divided by the resistor 55 and the reference signal level setting means 6. The midpoint of this voltage dividing circuit, that is, the potential applied to the reference signal level setting means 6 is input to the positive terminal of the operational amplifier 53.

このため、この基準信号レベル設定手段６の可変抵抗を
可変することにより、出力トランジスタ５２に流れる定
電流値が可変される。この定電流の変化は、この定電流
が通電する抵抗４２の電位降下の変化（従って第１図に
おける電位■、の変　　７化）をきたす。この結果、複
数の発熱体素子ＩＡに通電される定電流の値が極く容易
に上昇若しくは下降制御される。Therefore, by varying the variable resistance of the reference signal level setting means 6, the value of the constant current flowing through the output transistor 52 is varied. A change in this constant current causes a change in the potential drop of the resistor 42 through which this constant current is applied (therefore, a change in the potential (2) in FIG. 1). As a result, the value of the constant current applied to the plurality of heating elements IA can be controlled to increase or decrease very easily.

〔発明の効果〕〔Effect of the invention〕

本発明は以上のように構成され機能するので、これによ
ると、発熱体素子の抵抗値のバラツキや電源電圧の変動
、或いは周囲温度の変化等があっても、基準信号レベル
設定手段を適当に調整することにより、定電流値を幾分
高く設定することができ、これがため各発熱体素子の発
熱温度をほぼ同時に所定のインクリボンのインク溶融温
度以上に上昇せしめることができ、従って周囲の悪条件
下においても鮮明な熱転写を行うことができるという従
来にない優れた印字ヘッド発熱体駆動装置を提供するこ
とができる。Since the present invention is configured and functions as described above, the reference signal level setting means can be adjusted appropriately even if there are variations in the resistance value of the heating element, fluctuations in the power supply voltage, changes in the ambient temperature, etc. By adjusting the constant current value, it is possible to set the constant current value somewhat higher, which allows the heat generation temperature of each heating element to be raised almost simultaneously to the ink melting temperature of a predetermined ink ribbon. It is possible to provide an unprecedented and excellent print head heating element driving device that can perform clear thermal transfer even under various conditions.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の一実施例を示す回路図、第２図は従来
例を示す回路図である。 ＩＡ・・・・・・発熱体素子、２・・・・・・定電流出
力回路、４・・・・・・定電流制御回路、５・・・・・
・基準信号出力回路、６・・・・・・基準信号レベル設
定手段。FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional example. IA... Heating element, 2... Constant current output circuit, 4... Constant current control circuit, 5...
- Reference signal output circuit, 6...Reference signal level setting means.

Claims (1)

【特許請求の範囲】[Claims] （１）、発熱体素子に定電流を印加する定電流出力回路
と、この定電流出力回路の出力電流値を一定値に制御す
る定電流制御手段と、この定電流制御手段用の基準信号
を出力する基準信号出力回路とを備えた印字ヘッド発熱
体駆動装置において、前記基準信号出力回路が出力する
基準信号の出力レベルを必要に応じて任意に設定し得る
基準信号レベル設定手段を、前記基準信号出力回路に併
設したことを特徴とする印字ヘッド発熱体駆動装置。(1) A constant current output circuit that applies a constant current to the heating element, a constant current control means that controls the output current value of this constant current output circuit to a constant value, and a reference signal for this constant current control means. and a reference signal output circuit for outputting a reference signal, a reference signal level setting means capable of arbitrarily setting the output level of the reference signal output from the reference signal output circuit as required; A print head heating element drive device characterized by being attached to a signal output circuit.
JP2917087A 1987-02-09 1987-02-09 Driving device for printing head heat generating element Pending JPS63194961A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2917087A JPS63194961A (en) 1987-02-09 1987-02-09 Driving device for printing head heat generating element

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2917087A JPS63194961A (en) 1987-02-09 1987-02-09 Driving device for printing head heat generating element

Publications (1)

Publication Number Publication Date
JPS63194961A true JPS63194961A (en) 1988-08-12

Family

ID=12268765

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2917087A Pending JPS63194961A (en) 1987-02-09 1987-02-09 Driving device for printing head heat generating element

Country Status (1)

Country Link
JP (1) JPS63194961A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0562433A2 (en) * 1992-03-27 1993-09-29 Rohm Co., Ltd. Divisional-type thermal printhead

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0562433A2 (en) * 1992-03-27 1993-09-29 Rohm Co., Ltd. Divisional-type thermal printhead
EP0562433A3 (en) * 1992-03-27 1994-05-18 Rohm Co Ltd Divisional-type thermal printhead

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