JPH0369310B2 - - Google Patents
Info
- Publication number
- JPH0369310B2 JPH0369310B2 JP60193756A JP19375685A JPH0369310B2 JP H0369310 B2 JPH0369310 B2 JP H0369310B2 JP 60193756 A JP60193756 A JP 60193756A JP 19375685 A JP19375685 A JP 19375685A JP H0369310 B2 JPH0369310 B2 JP H0369310B2
- Authority
- JP
- Japan
- Prior art keywords
- gradation
- signal
- bit
- digital recording
- recording signal
- 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.)
- Expired - Lifetime
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
Landscapes
- Electronic Switches (AREA)
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明はプリンタ、フアクシミリなどの信号処
理装置に係わり、特に中間階調表示を伴う高品質
の画像記録に好適な熱転写プリンタに関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to signal processing devices such as printers and facsimiles, and particularly to a thermal transfer printer suitable for recording high-quality images with halftone display.
特開昭60−2385号公報には、発熱抵抗体それぞ
れの抵抗値のばらつきを補正する方法が述べられ
ている。この公知例では、発熱抵抗体のばらつき
に応じて、各発熱抵抗体に入力する電力を補正す
ることとしているが、この公知例では、二値記録
については、詳しく述べられているが、中間調表
示を伴なう画像記録の場合に必要な高精度の補正
については詳述していない。
Japanese Unexamined Patent Publication No. 60-2385 describes a method for correcting variations in resistance values of heating resistors. In this known example, the power input to each heating resistor is corrected according to variations in the heating resistors, but in this known example, binary recording is described in detail, but halftone The highly accurate correction required in the case of image recording accompanied by display is not described in detail.
本発明の目的は、熱転写プリンタの発熱回路に
おいて、各発熱抵抗体の抵抗値のばらつき、配線
の抵抗値のばらつき、駆動用トランジスタの特性
のばらつきなどを原因とする発熱回路ごとの抵抗
値のばらつきによる階調画像の濃度むらを高精度
に補正しうる実用的な中間調の熱転写プリンタを
提供することにある。
An object of the present invention is to solve the problem of variations in the resistance value of each heat generating circuit caused by variations in the resistance value of each heat generating resistor, variations in the resistance value of wiring, variations in the characteristics of driving transistors, etc. in the heat generating circuit of a thermal transfer printer. An object of the present invention is to provide a practical halftone thermal transfer printer capable of highly accurately correcting density unevenness of a gradation image.
発熱抵抗体及び配線の抵抗値、駆動用トランジ
スタの特性のばらつきによる発熱回路ごとの抵抗
値のばらつきに応じて転写情報を含す複数ビツト
のデイジタル信号たる記録信号の値を細かく補正
して、転写の際の濃度むらの発生を防止するため
に、本発明では、補正後の記録信号の階調信号で
従来無視していた小数部分をも考慮して階調制御
するとともに、補正後の記録信号を複数の部分に
分けてそれぞれについて階調制御を行なうことに
よつて、高品質・高速度の転写を可能にするもの
である。
The value of the recording signal, which is a multi-bit digital signal containing transfer information, is finely corrected according to the resistance value of each heat generating circuit due to the resistance value of the heat generating resistor and wiring, and the variation in the characteristics of the driving transistor. In order to prevent density unevenness from occurring when recording, the present invention performs gradation control in consideration of the decimal part of the gradation signal of the corrected recording signal, which was conventionally ignored. By dividing the image into a plurality of parts and controlling the gradation for each part, high-quality and high-speed transfer is possible.
第１図は本発明の実施例を示す図である。信号
変換用ROM１と係数選択用ROM２とカウンタ
３によつて信号補正回路が構成され、比較器４、
比較器５、階調カウンタ６、AND素子７、AND
素子８、NOT素子９、OR素子１０によつて階調
制御回路が構成されている。
FIG. 1 is a diagram showing an embodiment of the present invention. A signal correction circuit is composed of a signal conversion ROM 1, a coefficient selection ROM 2, and a counter 3, and a comparator 4,
Comparator 5, gradation counter 6, AND element 7, AND
The element 8, the NOT element 9, and the OR element 10 constitute a gradation control circuit.
信号補正回路へ入力されたｎビツトの記録信号
は、補正後ｐ＋ｑビツトの信号となり階調制御回
路へ入力される。 The n-bit recording signal input to the signal correction circuit becomes a p+q-bit signal after correction and is input to the gradation control circuit.
階調制御回路の出力は、第５図に示すように、
熱ヘツド５１上のシフトレジスタ５２に記録信号
入力として入力される。シフトレジスタで直並列
変換され、ラツチレジスタ５３を通して、発熱抵
抗体５５、駆動用トランジスタ５４、それらを接
続する配線、及びそれらと電流とを接続する配線
からなる発熱回路５６に入力され、熱転写が実行
される。 The output of the gradation control circuit is as shown in FIG.
The signal is input to a shift register 52 on a thermal head 51 as a recording signal input. It is converted into serial to parallel by a shift register, and is input through a latch register 53 to a heating circuit 56 consisting of a heating resistor 55, a driving transistor 54, wiring connecting them, and wiring connecting them to a current, and thermal transfer is performed. be done.
信号変換用ROM１には、ｎビツトの記録信号
に補正係数をかけた結果を書いておく。ｎビツト
の記録信号の値は０から2n−１まで2n個の値を取
り得る。これに補正係数をかけて補正すると、補
正後の値は一般に小数を含む数になる。従来、小
数部分については無視していたが、ここで、補正
後の値の整数部分の値をｐビツトで、小数点以下
の値をｑビツトであらわすこととすると、
ｎ＝ｐ ｎ＜ｐ＋ｑ
となる。ここで、ｎ＝ｐ＝６，ｑ＝２の場合を考
えると、64階調の画像を表現でき、かつ、最小で
２−q、すなわち0.25階調の巾で階調の補正が可
能である。 In the signal conversion ROM 1, the result of multiplying the n-bit recording signal by a correction coefficient is written. The value of the n-bit recording signal can take on 2 n values from 0 to 2 n -1. If this is corrected by multiplying it by a correction coefficient, the corrected value will generally be a number that includes a decimal. Conventionally, the decimal part was ignored, but if we now express the integer part of the corrected value in p bits and the value below the decimal point in q bits, then n=p n<p+q. . Now, if we consider the case where n = p = 6 and q = 2, it is possible to express an image with 64 gradations, and it is possible to correct the gradation with a minimum width of 2- q , that is, 0.25 gradations. .
記録信号が信号補正回路に入力されると、カウ
ンタ３によつて、記録信号と同期したクロツク信
号をカウントすることにより、入力された記録信
号が、熱ヘツドの複数個の発熱回路のどの発熱回
路に対応するかを係数選択用ROM２に教える。
係数選択用ROM２では、発熱回路に対応した信
号補正係数を信号変換用ROM１に教える。信号
変換用ROM１には６ビツトの記録信号に補正係
数をかけた結果がかかれており、補正後の値が整
数部６ビツト＋小数部２ビツトの形で出力され
る。 When the recording signal is input to the signal correction circuit, the counter 3 counts the clock signal synchronized with the recording signal to determine which of the plurality of heat generating circuits of the thermal head the input recording signal is. It tells the coefficient selection ROM 2 whether it corresponds to .
The coefficient selection ROM 2 teaches the signal correction coefficient corresponding to the heat generating circuit to the signal conversion ROM 1. The signal conversion ROM 1 stores the result of multiplying the 6-bit recording signal by a correction coefficient, and outputs the corrected value in the form of 6 bits for the integer part and 2 bits for the decimal part.
階調制御回路での処理について説明する。信号
変換用ROM１で補正されｐビツト、ｑビツトの
２部分に分れた記録信号は、切換信号がハイレベ
ルのときに、ｑビツトと階調カウンタ６の値と
が、比較器５で比較され、その結果がAND素子
８に送られる。切換信号がローレベルのときに、
ｐビツトと階調カウンタ６の内容とが比較器４で
比較され、その結果がAND素子７に送られる。
比較の結果と切換信号の論理積がハイレベルのと
きOR素子１０を通して、ハイレベルの信号が、
熱ヘツドに送られる。ここで、ｐ＝６，ｑ＝２と
して、比較器で行なわれる比較について説明す
る。階調カウンタとしては、３，２，１，１，
２，…63とカウントできるアツプダウンカウンタ
を使用する。最初、切換信号がハイレベルのと
き、比較器５においてｑビツトの取りうる値（ｑ
＝２ゆえ０，１，２，３の22通り。）とカウンタ
の内容（３，２，１と下降順にカウントされる。）
とを比較して、ｑビツトの値がカウンタの値以上
の大きさであれば、比較器５の出力をハイレベル
とする。ｑビツト部分の比較が終わると、切換信
号はローレベルになり、比較器４において、ｐビ
ツトの取りうる値（ｐ＝６ゆえ、０，１，２，…
…，62，63の26通り。）とカウンタの内容（１，
２，…62，63と上昇順にカウントされる。）とを
比較し、ｐビツトの値がカウンタの値以上の大き
さであれば、比較器４の出力をハイレベルとす
る。 The processing in the gradation control circuit will be explained. The recorded signal corrected by the signal conversion ROM 1 and divided into two parts, p bit and q bit, is compared with the value of the gradation counter 6 by the comparator 5 when the switching signal is at high level. , the result is sent to the AND element 8. When the switching signal is low level,
The p bit and the contents of the gradation counter 6 are compared by a comparator 4, and the result is sent to an AND element 7.
When the logical product of the comparison result and the switching signal is high level, the high level signal passes through the OR element 10,
Sent to heat head. Here, a comparison performed by a comparator will be described assuming p=6 and q=2. As a gradation counter, 3, 2, 1, 1,
Use an up-down counter that can count 2,...63. Initially, when the switching signal is at high level, the comparator 5 calculates the possible value of q bits (q
= 2, so 0, 1, 2, 3 2 2 ways. ) and the contents of the counter (counted in descending order of 3, 2, 1).
If the value of the q bit is greater than the value of the counter, the output of the comparator 5 is set to high level. When the comparison of the q bit portion is completed, the switching signal becomes low level, and the comparator 4 selects the possible values of the p bit (since p=6, 0, 1, 2, . . .
..., 62, 63, 2 6 ways. ) and the contents of the counter (1,
2,...62, 63 are counted in ascending order. ), and if the p-bit value is greater than the counter value, the output of the comparator 4 is set to high level.
第２図は、熱ヘツドの発熱回路ｉ，ｊについて
通電波形を示す。発熱回路ｉでは、7.75階調に対
応した通電時間であり、発熱回路ｊでは、3.25階
調に対応した通電時間である。０〜T1の間には
ｑビツト部分（本実施例では小数部分）に相当す
る通電が行なわれ、発熱回路ｉでは0.25階調分が
３回、発熱回路ｊでは0.25階調分が１回の通電が
行なわれる。次にT1〜T2の時間では、ｐビツト
部分（本実施例では整数部分）に相当する通電が
行なわれ、発熱回路ｉでは１階調分が７回、発熱
回路ｊでは１階調分が３回通電される。Ｏ〜T1
までの期間は、各発熱回路に対応する比較器５の
出力がハイレベルとなつた順番に順次通電され、
T1〜T2の期間では、各発熱回路に対応する比較
器４の出力がローレベルとなつた順番に順次、通
電を終了する。このようにすると、ｐビツト部分
とｑビツト部分とを連続して通電できるために、
ｐビツト部分とｑビツト部分が不連続な場合より
もより正確な発熱量を発生できる。 FIG. 2 shows the energization waveforms for the heating circuits i and j of the thermal head. In the heat generating circuit i, the energization time corresponds to 7.75 gradations, and in the heat generating circuit j, the energization time corresponds to 3.25 gradations. Between 0 and T1 , energization corresponding to q bit part (decimal part in this embodiment) is carried out, and in heating circuit i, electricity is applied three times for 0.25 gradation, and in heating circuit j, electricity is applied once for 0.25 gradation. energization is performed. Next, during the period from T 1 to T 2 , electricity corresponding to the p bit part (integer part in this example) is energized, and the heating circuit i is energized seven times for one gradation, and the heating circuit j is energized for one gradation. is energized three times. O~T 1
During this period, power is sequentially applied in the order in which the output of the comparator 5 corresponding to each heating circuit becomes high level.
During the period from T 1 to T 2 , energization is terminated in the order in which the output of the comparator 4 corresponding to each heating circuit becomes low level. In this way, the p-bit part and the q-bit part can be energized continuously, so that
A more accurate amount of heat can be generated than when the p bit part and the q bit part are discontinuous.
ここで、ｐビツトとｑビツトに分けて制御する
利点を説明する。例としてｎ＝６，ｐ＝６，ｑ＝
２をとると、記録信号の階調数は2n＝64となり、
階調カウンタ６は、ｑビツトの比較用に３回とｐ
ビツトの比較用に63回、計66回カウントすること
になる。一方、ｐビツトとｑビツトに分けずにｐ
＋ｑビツトとして、比較器を使用するには、階調
カウンタは、ｐ＝８，ｑ＝０の場合と同じで、28
−１＝255回カウントする必要がある。ライン型
の熱ヘツドを使う場合、記録信号は、直列に、各
階調ごとにどの発熱回路に通電すべきかの情報を
送る必要があるため、転送時間の関係で、電流の
パルス幅をあまり小さくすることが出来ない。こ
のため、ｐビツトとｑビツトとを分離すると、１
カウント当たりの電流パルスが同じ幅とすると、
255対66の時間比となることからわかるように、
より短い時間で熱転写が完了する。 Here, the advantage of controlling p bits and q bits separately will be explained. For example, n=6, p=6, q=
If we take 2, the number of gradations of the recording signal will be 2 n = 64,
The gradation counter 6 is used three times and p for comparison of q bits.
This results in a total of 66 counts, 63 times for comparison of bits. On the other hand, without dividing into p bits and q bits, p
To use the comparator as +q bits, the gray scale counter is the same as for p=8, q=0, 2 8
It is necessary to count -1 = 255 times. When using a line-type thermal head, it is necessary to send the recording signal in series, indicating which heating circuit should be energized for each gradation, so the current pulse width should not be made too small due to transfer time. I can't do that. Therefore, if p bits and q bits are separated, 1
Assuming the current pulses per count are the same width,
As can be seen from the time ratio of 255 to 66,
Thermal transfer is completed in a shorter time.
第２図においては、小数部分の階調を表示する
ため発熱回路に加える電流パルス幅は、１階調表
示のための電流パルス幅に比べて、狭い。しか
し、電流のパルス幅は最小限は、記録信号の伝送
時間により制限される。そこで、小数部の階調を
表示するための電流パルス幅を、整数部の階調を
表示するための電流パルス幅と同じとしたもの
が、第３図である。表示される階調は、発熱回路
に入力される電力に対応するので、本実施例で
は、発熱回路に入力する電力が一階調の２−q＝
0.25となるように、小数部分については、電圧を
低くしてある。このようにすると、電流パルスの
幅をあまり狭くしなくてもよいため、回路の作製
が容易であり、また、記録信号の転送時間に余裕
ができる。 In FIG. 2, the current pulse width applied to the heating circuit for displaying decimal gray scales is narrower than the current pulse width for displaying one gray scale. However, the pulse width of the current is limited to a minimum by the transmission time of the recording signal. Therefore, FIG. 3 shows a case in which the current pulse width for displaying the gradation of the decimal part is the same as the current pulse width for displaying the gradation of the integer part. The displayed gradation corresponds to the power input to the heating circuit, so in this example, the power input to the heating circuit is one gradation, 2- q =
The voltage is lowered for the decimal part so that it is 0.25. In this way, the width of the current pulse does not have to be made very narrow, so the circuit can be easily manufactured, and there is also a margin in the transfer time of the recording signal.
第４図は、本発明の他の実施例で、ROMとし
てヒユーズ式のROMを使い信号補正回路と階調
制御回路との回路全体を熱ヘツド搭載用回路１３
として、熱ヘツドの基板又は、熱ヘツドのフレキ
シブル絶縁板に装着し、回路を含めた熱ヘツドの
差し替えができるようにしてある。このように構
成すると熱ヘツドの製作時に発熱回路の抵抗値を
測定し、補正用の値を信号変換用ROM１、係数
選択用ROM２に書き込んでおけば、熱ヘツド交
換などの際には、新たな熱ヘツドの補正値を含む
ROMも同時に交換されるから、同時に発熱回路
の抵抗値の補正も達成できる。 FIG. 4 shows another embodiment of the present invention, in which a fuse-type ROM is used as the ROM, and the entire circuit including the signal correction circuit and the gradation control circuit is mounted on a thermal head mounting circuit 13.
It is attached to the thermal head's board or the thermal head's flexible insulating plate, so that the thermal head including the circuit can be replaced. With this configuration, if the resistance value of the heating circuit is measured when the thermal head is manufactured and the correction value is written to the signal conversion ROM1 and coefficient selection ROM2, it is possible to use a new thermal head when replacing the thermal head. Includes thermal head correction value
Since the ROM is also replaced at the same time, the resistance value of the heating circuit can be corrected at the same time.
本発明によれば、高精度の階調制御が出来、熱
ヘツドの発熱回路の発熱に関するばらつきを精度
良く補正できるので、濃度むらを充分小さくで
き、画質の向上が図れ、かつ、実用的な中間調の
熱転写プリンタを得ることが出来る。
According to the present invention, it is possible to perform high-precision gradation control and to accurately correct variations in heat generation in the heating circuit of the thermal head, thereby making it possible to sufficiently reduce density unevenness, improve image quality, and provide a practical intermediate It is possible to obtain a thermal transfer printer with a similar tone.
第１図は本発明の一実施例を示す回路ブロツク
図、第２図及び第３図は、通電々流の波形図、第
４図は本発明の別の実施例を示す図、第５図は発
熱回路を示す図である。
１……信号変換用ROM、２……係数選択用
ROM、３……カウンタ、４……比較器、５……
比較器、６……階調カウンタ、１３……熱ヘツド
搭載用回路、５１……熱ヘツド、５２……シフト
レジスタ、５３……ラツチレジスタ、５４……駆
動用トランジスタ、５５……発熱抵抗体。
FIG. 1 is a circuit block diagram showing one embodiment of the present invention, FIGS. 2 and 3 are waveform diagrams of energizing current, FIG. 4 is a diagram showing another embodiment of the present invention, and FIG. 5 is a diagram showing a heat generating circuit. 1...ROM for signal conversion, 2...For coefficient selection
ROM, 3... Counter, 4... Comparator, 5...
Comparator, 6... Gradation counter, 13... Thermal head mounting circuit, 51... Thermal head, 52... Shift register, 53... Latch register, 54... Drive transistor, 55... Heat generating resistor .
Claims (1)
する複数の発熱回路を有する発熱ヘツドと、 ｎビツト（ｎ≧２）の整数階調のデイジタル記
録信号に、前記発熱回路毎の発熱に関するばらつ
きに対応して補正係数をかけて、ｐビツト（ｐ≧
２）の整数階調のデイジタル記録信号とｑビツト
（ｑ≧１）の小数階調のデイジタル記録信号とを
出力する信号補正回路と、 前記ｐビツトの整数階調のデイジタル記録信号
とカウンタの値とに基づき生成され、前記ｐビツ
トの整数階調のデイジタル記録信号に対応する通
電時間の電力信号と、 前記ｐビツトの整数階調の１階調のデイジタル
記録信号に対応する前記電力信号の通電時間より
短い通電時間、または前記ｐビツトの整数階調の
デイジタル記録信号に対応する前記電力信号の電
圧より低い電圧を有し、前記ｑビツトの小数階調
のデイジタル記録信号とカウンタの値とに基づき
生成され、前記ｑビツトの小数階調のデイジタル
記録信号に対応する通電時間の電力信号と を連続して前記発熱回路に供給する階調制御回路
と を備えることを特徴とする熱転写プリンタ。 ２ 特許請求の範囲第１項記載の熱転写プリンタ
において、 前記発熱回路と、前記信号補正回路と、前記階
調制御回路とを同一基板上に設けることを特徴と
する熱転写プリンタ。[Scope of Claims] 1. A heat generating head having a plurality of heat generating circuits that each generate heat by being supplied with electric power, and a digital recording signal of an n-bit (n≧2) integer gradation, each of the heat generating circuits By multiplying by a correction coefficient corresponding to the dispersion in heat generation, p bits (p≧
2) a signal correction circuit that outputs the integer gradation digital recording signal and the q-bit (q≧1) decimal gradation digital recording signal; and the p-bit integer gradation digital recording signal and the counter value. a power signal with an energization time corresponding to the p-bit integer gradation digital recording signal; and a power signal corresponding to the p-bit integer gradation one-gradation digital recording signal. or a voltage lower than the voltage of the power signal corresponding to the p-bit integer gradation digital recording signal, and the q-bit decimal gradation digital recording signal and the counter value. a gradation control circuit that continuously supplies to the heating circuit a power signal generated based on the q-bit decimal gradation digital recording signal and a power signal corresponding to the energization time. 2. The thermal transfer printer according to claim 1, wherein the heating circuit, the signal correction circuit, and the gradation control circuit are provided on the same substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19375685A JPS6255169A (en) | 1985-09-04 | 1985-09-04 | Thermal transfer printer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19375685A JPS6255169A (en) | 1985-09-04 | 1985-09-04 | Thermal transfer printer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6255169A JPS6255169A (en) | 1987-03-10 |
| JPH0369310B2 true JPH0369310B2 (en) | 1991-10-31 |
Family
ID=16313288
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19375685A Granted JPS6255169A (en) | 1985-09-04 | 1985-09-04 | Thermal transfer printer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6255169A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0832455B2 (en) * | 1988-03-08 | 1996-03-29 | 松下電送株式会社 | Recording pulse width control device for thermal recording device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6071270A (en) * | 1983-09-29 | 1985-04-23 | Fuji Xerox Co Ltd | Thermal head |
-
1985
- 1985-09-04 JP JP19375685A patent/JPS6255169A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6255169A (en) | 1987-03-10 |
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