JP2005037478A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus for forming an image with good productivity even when modifying a conveying speed of a transfer material in the case of forming the image by alternatingly using the transfer materials of which heat capacities are large and small. <P>SOLUTION: The image forming apparatus is provided with a control means for forming the image by modifying the conveying speed of the transfer material in response to the sort of the transfer material. The control means calculates and compares a first image formation time in a first image formation mode and a second image formation time in a second image formation mode when forming the image on the basis of JOB information and JOB data, and forms the image in a shorter image formation mode in the image formation mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

（ロ）厚紙の前搬送量をＬＢとし、ＴＢを求める。
【０１１１】

（ハ）設定変更時間Ｒの合計ＴＲを求める。
【０１１２】
ＴＲ＝Ｒ×１９回＝１０ｓｅｃ×１９＝１９０ｓｅｃ
（ニ）Ｔ１＝ＴＡ＋ＴＢ＋ＴＲを求める。
【０１１３】

（２）定着温度ＴＣを２００℃とし、ＪＯＢデータ中の最低の搬送速度ＶＣを３００ｍｍ／ｓｅｃとして、普通紙及び厚紙を合計２０枚搬送した場合の全出力を完了するまでに必要な画像形成時間Ｔ２を求める。
【０１１４】
（ホ）普通紙と厚紙の全搬送距離Ｌ２を求める。

（ヘ）ＪＯＢデータ中の最低の搬送速度で搬送した場合の画像形成時間Ｔ２を求める。
【０１１５】

（３）Ｔ１とＴ２を比較する。
【０１１６】
Ｔ１＝２０６．２ｓｅｃ＞Ｔ２＝２０．３ｓｅｃ
この場合、ＪＯＢデータ中の最低の搬送速度（最低搬送速度ともいう。）で全ての出力を行った方が、全ての出力を完了するまでの画像形成時間が短くなるため、最低搬送速度で出力するようにすると生産性が向上することが解る。
【０１１７】
従って、転写材の種類に応じた搬送速度で画像形成を行う第１の画像形成モードと、ＪＯＢデータ中の最低搬送速度で画像形成を行う第２の画像形成モードとを備え、画像形成を行う際に、第１の前記画像形成モードによる第１の画像形成時間と、第２の前記画像形成モードによる第２の画像形成時間とを算出して比較し、画像形成時間が短い方の画像形成モードで画像形成を行うようにすれば、生産性の良い画像形成装置を提供できることになる。
【０１１８】
次に、転写材の搬送速度を変更した場合の画像形成に関する制御対象項目の制御値の変更について説明する。
【０１１９】
転写材の搬送速度を変更した場合は、その変更に伴い、例えば、下記に示す制御対象項目の制御値を変更しなければならない。
【０１２０】
しかしながら、転写材の搬送速度に対する制御対象項目の制御値を全て記憶手段１６０に記憶したのでは、膨大なデータとなってしまう。そこで、例えば、転写材の種類に応じた搬送速度に対して変更された搬送速度の変化分を求め、この変化分に基づく演算により、変更された搬送速度に対する制御値を求めることで、この問題を解決することができる。
【０１２１】
具体的には、本発明の実施の形態においては、例えば、使用頻度の高い普通紙の搬送速度、及び、制御値を記憶しておき、これらの値を基に、線速比を求めて、搬送速度変更後の制御値を求めるようにした。
【０１２２】
例えば、転写材Ａの搬送速度（線速ともいう。）Ａを５００ｍｍ／ｓｅｃ、変更される線速Ｂを３００ｍｍ／ｓｅｃとした場合、線速Ａに対する線速Ｂの変化分（線速比ともいう。）Ｃは、Ｃ＝Ｂ／Ａ＝３００（ｍｍ／ｓｅｃ）／５００（ｍｍ／ｓｅｃ）＝０．６となる。
【０１２３】
従って、線速Ｂの場合、下記（１）〜（７）の制御対象項目の制御値の変化は、線速Ａの場合の制御値に線速比Ｃ（０．６）を剰じた値となり以下のようになる。
＜データ＞

制御対象項目について説明する。
（１）帯電電流は、線速が変わることにより、単位時間当たりに感光体ドラムに与えるべき電荷量が変わるために線速の変化分だけ変化させる。
（２）帯電グリット電圧は、線速が変わっても感光体ドラムの帯電電位を変更しないため、線速が変わっても変更しないでよい。
（３）現像スリーブ回転速度は、感光体ドラムと現像スリーブの速度比を一定にする必要があるため、線速が変わると、線速の変化分だけ変化させる。
（４）転写電流は、線速が変わることにより、単位時間当たりに転写紙に与えるべき電荷量が変わるために、線速の変化分だけ変化させる。
（５）分離直流（ＤＣ）電流は、線速が変わることにより、単位時間当たりに転写紙に与えるべき電荷量が変わるために、線速の変化分だけ変化させる。
（６）分離交流（ＡＣ）電流は、固定値出力としているため、線速が変わっても変更しないでよい。
（７）定着目標温度は、ホットオフセット（定着抜け）や定着アンダーなどの不具合が起こらない範囲であれば、変更する必要なし。但し、紙の種類や環境などの条件によっては、変更する必要がある場合もある。
【０１２４】
すなわち、搬送速度を変更した場合は、前述のように線速比を求め、変更前の線速に基づき設定されていた制御対象項目の制御値に対して、線速比を乗ずることで、変更後の線速に対応する制御対象項目の制御値を求めることが簡単にできる。
【０１２５】
従って、搬送速度を変更する制御を行う場合に、前述のような演算を行えば良く、あらゆる搬送速度に対応する制御対象項目の制御値を記憶手段に記憶させておく必要がないので、記憶手段の記憶容量を膨大なものにする必要はない。
【０１２６】
また、制御値を求める演算も簡単な演算で良いので、演算プログラムも簡単で良く制御回路や制御動作を複雑にする必要がない。
【０１２７】
次に、図３により本発明に係る画像形成動作の手順について説明する。なお、説明にあたって、適宜、図１及び図２を参照して詳細に説明する。
【０１２８】
（ＳＴ１）
まず最初に、ＪＯＢ情報を入力するステップである。例えば、画像形成装置がプリンタの場合は、ＣＰＵ１１０の指示により、情報制御回路１２０はインターフェース（Ｉ／Ｆ）１３０を介して外部情報機器５００からＪＯＢ情報及びＪＯＢデータによりデータを入力し、記憶手段１６０に記憶される。
【０１２９】
また、画像形成装置が複写機の場合は、同様に、画像読取手段１３やインターフェース（Ｉ／Ｆ）１３０を介して外部情報機器５００から入力されたＪＯＢ情報及びＪＯＢデータ等が記憶手段１６０に記憶される。
【０１３０】
ＪＯＢ情報及びＪＯＢデータが１ＪＯＢ単位で入力され記憶手段１６０に記憶されるとＳＴ２に進む。
【０１３１】
（ＳＴ２）
転写材を変更して画像形成を行うようになっているか否かを判断するステップである。ＣＰＵ１１０の指示により、情報制御回路１２０が画像形成を実行するために１つのＪＯＢ情報を記憶手段１６０から読み出した時に、このＪＯＢ情報に含まれる個々のＪＯＢを検索して、そのＪＯＢ情報の中に転写材を変更して画像形成を行うようなＪＯＢがある場合はＳＴ３に進み、転写材を変更しないで画像形成を行うようになっている場合はＳＴ１１に飛ぶ。
【０１３２】
（ＳＴ３）
このステップを通過するのが１部目か否かを判断するステップである。画像形成を行う場合に、ＣＰＵ１１０の指示により、情報制御回路１２０が１部目であることを検出したときはＳＴ４に進み、それ以外の部数である場合はＳＴ６に飛ぶ。
【０１３３】
（ＳＴ４）
このステップを通過するのが１枚目か否かを判断するステップである。画像形成を行う場合に、ＣＰＵ１１０の指示により、情報制御回路１２０が１枚目であることを検出したときはＳＴ５に進み、それ以外の部数である場合はＳＴ６に飛ぶ。
【０１３４】
（ＳＴ５）
ＪＯＢ情報及びＪＯＢデータにより、第１の画像形成モードによる第１の画像形成時間（Ａ方式という。）と、第２の画像形成モードによる第２の画像形成時間（Ｂ方式という。）とを演算するステップである。
【０１３５】
ＣＰＵ１１０の指示により、情報制御回路１２０が記憶手段１６０から読み出したＪＯＢ情報及びＪＯＢデータにより、Ａ方式とＢ方式の画像形成時間を演算する。
【０１３６】
演算されたＡ方式とＢ方式の画像形成時間は記憶手段１６０に記憶されるようになっているので、１つのＪＯＢ情報に対しては１回、すなわち、複数部数の画像形成を行う場合においても、最初の１回のみ演算を実行すれば良い。
【０１３７】
なお、演算する場合の方式として、２つの方式がある。１つはＪＯＢ単位で演算する方式である。この場合は、全てのＪＯＢを考慮して、画像形成時間が演算できるので、演算がやや複雑になるが、画像形成時間を比較する場合に、正確な比較が行える利点がある。
【０１３８】
もう一つは、一定ページ数を単位として演算する方式であり、簡単に演算することができる利点があるが、反面、例えば、一定ページ数の設定によっては、誤差が生じやすく、特に、一定ページ数と出力部数に大きな差があるようなものの画像形成時間の比較には不向きである。
【０１３９】
つまり、画像形成時間の比較を行う際に、ＪＯＢ単位で比較するか、一定ページ数単位で比較するかを、これらの特徴を考慮した上で決定し、この決定に従って演算するように設定する必要がある。
【０１４０】
従って、どちらの方式で比較するかを、例えば、ＪＯＢ情報の部数により自動的に判断して演算するように設定すると便利である。また、コントロールパネルＣＰによりＪＯＢ単位でどちらの方式で比較するかを設定できるようにしたり、一定ページ数単位のページ数を設定できるようにしておくと更に便利である。
【０１４１】
（ＳＴ６）
Ａ方式とＢ方式の画像形成時間を比較するステップである。ＣＰＵ１１０の指示により、情報制御回路１２０がＳＴ５ステップで求められたＡ方式とＢ方式の画像形成時間を比較する。Ａ方式の画像形成時間が短い場合はＳＴ７に進み、Ｂ方式の画像形成時間が短い場合はＳＴ１０に飛ぶ。
【０１４２】
（ＳＴ７）
Ａ方式の場合の搬送速度に応じた制御項目の制御値を求め設定するステップである。搬送速度に関連する制御項目の制御値は、前述のように変更前の転写材の搬送速度に対する線速比を求め、求めた線速比を変更前の制御値に乗ずることにより求められる。ＣＰＵ１１０の指示により、情報制御回路１２０が制御値を求め、求められた制御値が駆動制御回路１５０等の関連する制御項目毎に設定されるとＳＴ８に進む。
【０１４３】
なお、求められた制御値を搬送速度に関連付けて記憶手段１６０に記憶するようにしておけば、演算を繰り返すこともなく、必要に応じて記憶手段１６０から読み出して使用することができるので便利である。
【０１４４】
また、変更前の搬送速度及び制御値の代わりに、予め設定された幾つかの転写材に応じた搬送速度及び制御値の中から選択して使用しても良く、また、多用される普通紙の搬送速度及び制御値を用いるようにしても良い。
【０１４５】
（ＳＴ８）
ＪＯＢ情報とＪＯＢデータ、及び搬送速度に関連する制御値等に基づきＡ方式での画像形成動作を行うステップである。
【０１４６】
ＣＰＵ１１０の指示により、画像処理回路１４０と駆動制御回路１５０が協働して画像形成手段１１や給排紙手段１４等を作動させ画像形成動作を行う。そして、予め設定された画像形成単位での画像形成動作が終了するとＳＴ９に進む。
【０１４７】
なお、予め設定された画像形成単位とは、例えば、転写材１枚毎、あるいは１部数毎の単位をいい、何れの単位で画像形成を行うか否かは、予めコントロールパネルＣＰにより設定できるようになっている。
【０１４８】
従って、画像形成単位として転写材１枚毎の画像形成動作が設定されていると、１枚分の画像形成動作が終了するとＳＴ９に進み、１部数毎の画像形成動作が設定されていると、１部数分の画像形成動作が終了するとＳＴ９に進む。
【０１４９】
（ＳＴ９）
全てのＪＯＢが終了したか否かを判断するステップである。出力部数は予めコントロールパネルＣＰにより設定できるようになっており、ＣＰＵ１１０の指示により、設定された出力部数と出力された部数とが一致するか否かを情報制御回路１２０が判断するようになっている。
【０１５０】
そして、設定された出力部数と出力された部数とが一致したときは、画像形成動作を終了し、一致していないときはＳＴ２に飛ぶ。
【０１５１】
（ＳＴ１０）
Ｂ方式の場合の搬送速度に応じた制御項目の制御値を求め設定するステップである。Ａ方式と同様に、ＣＰＵ１１０の指示により、情報制御回路１２０が搬送速度に関連する制御項目の制御値を求め、求められた制御値を駆動制御回路１５０等の関連する制御項目毎に設定されるとＳＴ１１に進む。
【０１５２】
なお、求められた制御値は、Ａ方式と同様に、搬送速度に関連付けて記憶手段１６０に記憶するようになっている。
【０１５３】
（ＳＴ１１）
ＪＯＢ情報とＪＯＢデータ、及び求められた制御値等に基づきＢ方式での画像形成動作を行うステップである。
【０１５４】
Ａ方式と同様に、ＣＰＵ１１０の指示により、画像処理回路１４０と駆動制御回路１５０が協働して画像形成手段１１や給排紙手段１４等を作動させ画像形成動作を行う。そして、予め設定された画像形成単位での画像形成動作が終了するとＳＴ９に進む。
【０１５５】
（ＳＴ１２）
転写材に応じた搬送速度と制御値に基づく画像形成動作を行うステップである。ＪＯＢ情報の中に転写材の変更を行うＪＯＢが無いので、ＪＯＢ情報の中に設定されている唯一の転写材について、搬送速度に応じた制御値を設定し画像形成動作を行う。そして、予め設定された画像形成単位での画像形成動作が終了するとＳＴ９に進む。
【０１５６】
なお、この場合、普通紙のように転写材が汎用の転写材として多用されるような場合には、多用される幾つかの転写材について、予め転写材の搬送速度と制御値をテーブル化して記憶手段１６０に記憶するようにしておくと、転写材の種類を設定するだけで搬送速度と制御値が設定できるようになるので便利である。
【０１５７】
以上のように、本発明に係る画像形成装置の制御手順について説明したが、本発明は、定着装置において転写材の定着を行う際に、転写材の種類に応じて設定された搬送速度が異なる場合に、転写紙の種類に応じた搬送速度、又は、ＪＯＢデータ中の最低搬送速度で画像形成を行った場合の画像形成時間を比較して、画像形成時間が短い方の画像形成モードで画像形成を行うようにしたので、画像品質を劣化させることなく、生産性を向上させることができるようになった。
【０１５８】
なお、熱容量の大きい転写材と小さい転写材の例として、インデックス用紙と普通紙が混在する場合を一例として説明してきたが、平滑度の高い転写紙と低い転写紙との組み合わせも含めて、転写紙の組み合わせはこの組み合わせに限らず、他の組み合わせにおいても画像形成時間を比較し、画像形成時間が短い方の画像形成モードで画像形成を行うようにすれば、常に、生産性を向上させることができる。
【０１５９】
また、一定ページ数単位で簡単に画像形成時間の演算を行い簡単に比較したり、１つの印刷単位である１ＪＯＢ単位の情報で画像形成時間の演算を行い正確な比較を行ったりすることができるようにしたので、ＪＯＢ情報に応じて、最適な方式で比較ができるので、生産性を向上させることができる。
【０１６０】
更に、搬送速度を変更しても、搬送速度比を求めることで各制御値を簡単に求めることができるので、搬送速度に対する制御値を全て記憶しておく必要がなく、記憶手段の記憶容量を小さなものにできるので、制御回路を安価なもので構成でき、かつ、生産性を向上させることができるようになった。
【０１６１】
【発明の効果】
本発明は、転写材の種類に応じた搬送速度で画像形成を行う場合と、ＪＯＢデータ中の最低搬送速度で画像形成を行う場合の画像形成時間を比較し、短い時間となる画像形成モードで画像形成を行うので、常に生産性の良い画像形成ができる画像形成装置を提供できる。
【０１６２】
更に、搬送速度を変更しても、搬送速度比を求めることで各制御値を簡単に求めることができ、画像形成に係る制御値が、適切な制御値で制御され定着不良が発生することがなく、生産性の良い画像形成ができる画像形成装置を提供できる。
【図面の簡単な説明】
【図１】画像形成装置の構成を示す概略図。
【図２】画像形成装置の回路構成を示すブロック図。
【図３】画像形成装置の制御手順を示すフローチャート。
【符号の説明】
１ 筐体
２ 手差し皿
３ 排紙皿
４ ローラ
５ 感光体ドラム
６ 帯電手段
７ 現像手段
８ 転写分離手段
９ クリーニング手段
１０ 定着手段
１１ 画像形成手段
１２ 給紙カセット
１３ 画像読取手段
１４ 給排紙手段
２０ 画像形成装置
３０ 自動原稿送り装置
３１ ＡＤＦ筐体
３２ 原稿載置台
３３ 排紙部
３４ 送りローラ
３５ 搬送ローラ（Ａ）
３６ 搬送ローラ（Ｂ）
３７ ローラ
３８ 読取ローラ
３９ 排紙ローラ
４０ 反転部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile.
[0002]
[Prior art]
In recent years, image forming apparatuses such as copying machines, printers, and facsimiles have been increased in speed and resolution. In order to cope with high speed and high resolution, the image forming apparatus must be capable of forming a high resolution image at high speed on various recording members used.
[0003]
In an image forming apparatus using an electrophotographic system, in order to form a high-resolution image at high speed, a toner image transferred onto these recording members (also referred to as transfer materials) is stably fixed at a high resolution. There is a need.
[0004]
As a fixing device, a thermal fixing device is widely used. The thermal fixing device is configured to press a pressure roller against a fixing roller heated by a heat source (heater), and heat and transfer a transfer material while being sandwiched and conveyed by both rollers. A heat roller type that fixes an unfixed toner image by pressure is often used. At the time of fixing, the amount of heat generated per unit time of the heater is controlled to maintain the surface temperature of the fixing roller at a predetermined fixing temperature, and the toner image on the transfer material is kept within the proper range at the nip portion of the fixing roller and the pressure roller. The amount of heat is given.
[0005]
When heat is applied to the toner image on the transfer material, if the applied heat of fixing is large, the toner particles are likely to be melted by heat so that spot-off (collapse) is likely to occur or wrinkles occur on the transfer material. Or In addition, when the amount of fixing heat is small, the toner particles are insufficiently softened and fixing defects are likely to occur.
[0006]
Therefore, the optimum heat amount control in the heat fixing apparatus is performed when the transfer material conveyance speed is high (when the image resolution is low) and the fixing target control temperature is set high, and when the transfer material conveyance speed is low (image resolution). If the fixing target control temperature is set low when the temperature is high), it is possible to achieve the most suitable amount of heat for fixing.
[0007]
However, if the fixing target control temperature (also referred to as the fixing target temperature) is finely changed according to the resolution as described above, the control itself becomes complicated, and if the fixing target temperature is raised or lowered, There is a problem that it takes time until the fixing target temperature is stabilized, and the productivity of the image forming apparatus deteriorates.
[0008]
Therefore, in an image forming apparatus equipped with a thermal fixing device, the transfer material conveyance speed can be changed to at least three types, and the fixing target control temperature of the thermal fixing device can be changed according to the transfer material conveyance speed. When the transfer material transport speed is equal to or higher than a predetermined speed, the fixing target control temperature of the heat fixing device is set to a predetermined constant temperature. When the transfer material transport speed is lower than the predetermined speed, the heat fixing device is transferred. It has been proposed to control the temperature at a fixing target control temperature corresponding to the conveying speed of the material (see, for example, Patent Document 1).
[0009]
[Patent Document 1]
JP 2001-154533 A
[0010]
[Problems to be solved by the invention]
However, in order to cope with higher resolution, the above proposal pays attention to the fact that, even if the transfer speed of the transfer material is increased beyond a certain temperature, the transfer material can be fixed without causing any problems. Although it is intended to simplify the control by limiting the temperature control range corresponding to the transport speed, the target fixing temperature is changed according to the transfer speed of the transfer material, although the range is limited. Therefore, the problem that it takes time to stabilize the fixing target temperature when the fixing target temperature is changed has not been solved.
[0011]
Therefore, in Patent Document 1, when the sheet reaches the fixing device, the point at which temperature control is started is changed so that the fixing temperature reaches the fixing target temperature, and further, the fixing temperature becomes the fixing target temperature. Instead of waiting at the paper feed cassette, it waits at the paper holding unit immediately before the photosensitive drum so that this wasted time does not appear to be wasted time. In addition, there is a problem that the control of the image forming apparatus is complicated, and as a result, the productivity of the image forming apparatus is deteriorated.
[0012]
In addition to the above problems, in the fixing device, when a thick transfer material or a material with low surface smoothness is used, the amount of fixing heat given to the transfer material increases and the fixing target temperature is raised. Although there is an upper limit on the target fixing temperature, there is a case where it is necessary to control the amount of heat applied by lowering the transfer speed of the transfer material instead of increasing the target fixing temperature. .
[0013]
Therefore, it is conceivable to control the amount of heat applied to the transfer material by changing the transport speed while keeping the fixing temperature constant in the vicinity of the upper limit for safety instead of controlling the target fixing temperature.
[0014]
However, if the transfer speed of the transfer material is simply changed to solve the problem related to fixing, for example, it becomes necessary to match the rotation speed of the photosensitive drum with the transfer speed of the transfer material, Dew A series of change setting processes for changing the rotational speed of the polygon mirror in the optical process in accordance with the rotation speed of the photosensitive drum must be performed. To perform such a change setting process, at least 10 seconds or more is required. Time is required.
[0015]
Therefore, when image formation (also referred to as output) is performed by alternately using a transfer material having a large heat capacity and a transfer material having a small heat capacity, the change setting process is repeated if the transfer speed of the transfer material is changed. Since it takes a lot of time, the control of the entire image forming process is greatly affected, and the productivity of the image forming apparatus deteriorates.
[0016]
In view of the above problems, the present invention is capable of forming an image with high productivity even when the transfer speed of the transfer material is changed when the image formation is performed by alternately using a transfer material having a large heat capacity and a transfer material having a small heat capacity. An object is to provide an apparatus.
[0017]
[Means for Solving the Problems]
The object is achieved by adopting the following configuration.
[0018]
(1) In an image forming apparatus provided with a control unit capable of changing the conveyance speed of a transfer material in accordance with the type of transfer material to cause image formation.
JOB information storage means for storing JOB information relating to image formation of a document in JOB units, and the JOB data for storing the conveyance speed according to the type of transfer material and the change setting time for changing the conveyance speed as JOB data. A data storage unit, a first image forming mode in which image formation is performed at the conveyance speed according to the type of transfer material, and a second image formation mode in which image formation is performed at the minimum conveyance speed in the JOB data. The control means, when performing image formation based on the JOB information and the JOB data, a first image formation time in the first image formation mode and a second image in the second image formation mode. An image forming apparatus comprising: calculating and comparing a forming time and performing image formation in the image forming mode having a shorter image forming time.
[0019]
(2) The image forming apparatus according to (1), wherein the control unit calculates the first and second image forming times in units of one JOB.
[0020]
(3) The image forming apparatus according to (1), wherein the control unit performs the calculation of the first and second image forming times in units of a certain number of pages.
[0021]
(4) In the case where image formation is performed at another transport speed different from the transport speed according to the type of transfer material, the control unit performs another transport speed with respect to the transport speed according to the type of transfer material. And a second control value obtained by multiplying the first control value when image formation is performed at the transport speed according to the type of transfer material by the transport speed ratio. The image forming apparatus according to (1), wherein image formation is performed.
[0022]
(5) The first and second control values are at least one control value of a charging output for image formation, a developing sleeve rotation speed, a transfer output, a separation output, and a fixing target temperature. The image forming apparatus according to (4).
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
[0024]
FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus. FIG. 2 is a block diagram illustrating a circuit configuration of the image forming apparatus. FIG. 3 is a flowchart showing a control procedure of the image forming apparatus.
[0025]
In addition, in each drawing, the thing of the same code | symbol shall show the same thing, and shall be demonstrated in detail with reference to other drawings suitably.
[0026]
The configuration of the image forming apparatus according to the present invention will be described with reference to FIG.
The image forming apparatus according to the embodiment of the present invention is an electrophotographic copying machine for the sake of simplicity. Since the electrophotographic copying machine is well known, the parts not directly related to the present invention will be described briefly.
[0027]
Reference numeral 20 denotes the entire image forming apparatus. A relatively small amount of normal transfer material (also referred to as plain paper) P such as paper or an OHP sheet is supplied to the right side surface of the housing 1 of the image forming apparatus 20. A manual feed tray 2 is provided.
[0028]
Further, a normal transfer material P on which an image has been formed and discharged, or an index transfer material (also referred to as an index sheet) IP for forming an image based on an index document, which will be described later, is discharged to the left side. A paper discharge tray 3 is provided for stacking.
[0029]
A control panel CP as a display unit and an operation input unit for operating the image forming apparatus 20 is provided in the upper part of the front surface of the housing 1.
[0030]
In the control panel CP, for example, a liquid crystal display device or a liquid crystal display device DP as a display means in which a touch panel or the like is incorporated in the display device, a keyboard KB for inputting numerical values, and a series of image forming operations such as copying And an input device including a start button (also referred to as a copy button) SK or the like.
[0031]
A plurality of rollers 4 are provided on the bottom surface of the housing 1 so that the image forming apparatus 20 can be moved.
[0032]
Inside the housing 1, a control unit EC, an image forming unit 11, an image reading unit 13, a paper supply / discharge unit 14 and the like are provided.
[0033]
The control means EC is also called a control circuit, and is a means for controlling all operations of the image forming apparatus 20, and is composed of an electric circuit including a CPU and the like which will be described later. Based on a control program or control data stored in advance in the CPU, all means constituting the image forming apparatus 20 are driven and controlled.
[0034]
The image forming unit 11 is a unit for forming an image based on image information of a document.
[0035]
For example, a photosensitive drum 5 that rotates in a predetermined image forming direction (arrow Y) by a driving source such as a motor, charging means 6 that uniformly charges the photosensitive drum 5, and image information (also referred to as image data) of a document. ) And developing means 7 for developing the electrostatic latent image formed on the photosensitive drum 5 as a toner image, and the photosensitive drum. Transfer separation means 8 for transferring the toner image formed on the transfer material P to the transfer material P, etc., for scraping off the toner and paper dust remaining on the photosensitive drum 5 after the toner image is transferred to the transfer material P, etc. The cleaning unit 9 and the fixing unit 10 for melting and fixing the transferred toner image to the transfer material P are included.
[0036]
The fixing means is a heat roller system in which a pressure roller is pressed against a fixing roller heated by a heat source (heater), and an unfixed toner image is fixed by heat and pressure while the transfer material is sandwiched and conveyed by both rollers. The heat fixing device.
[0037]
The transfer material conveyance speed set in the fixing unit is set to either a conveyance speed corresponding to the type of the transfer material or a minimum conveyance speed in the JOB data, as will be described in detail later.
[0038]
The image reading unit 13 includes a reading optical system including a light source LT, mirrors MR1, MR2, MR3, an imaging lens LZ, and the like, and a reading device ES including an electric circuit including a CCD (solid-state imaging device). Yes.
[0039]
When the image forming apparatus 20 is a copying machine, the reading device ES reads image information of a document placed on a platen glass (not shown) or an original document transported to a reading position by an automatic document feeder 30. The image data is converted into digital image data and stored in storage means 160 described later.
[0040]
When the original conveyed by the automatic document feeder (ADF) 30 is read by the image reading means 13, the original conveyed to the reading position is irradiated by the light source LT, and the original is read from the original via the mirrors MR1, MR2, and MR3. The reflected light is imaged on the CCD surface of the reader ES by the imaging lens LZ, and image information output from the CCD is stored as image data.
[0041]
The paper supply / discharge unit 14 includes a paper supply cassette 12 and a paper supply / discharge conveyance device including a motor as a drive source and a plurality of rollers.
[0042]
The paper feed cassette 12 includes, for example, an index paper cassette 12a that stores index paper IP and a plain paper cassette 12b that stores plain paper P.
[0043]
Although the details will be described later after the index paper IP or plain paper P is selected based on the original in accordance with an instruction from the control means EC, the paper supply / discharge conveyance device depends on the type of transfer material such as the index paper IP or plain paper P. The motor is rotated at the transport speed, and a plurality of rollers and the like are rotationally driven to feed and feed the index paper IP or plain paper P from the paper feed cassette 12 toward the photosensitive drum 5 at an appropriate timing. After being formed, the paper is conveyed to the paper discharge tray 3.
[0044]
An automatic document feeder (ADF) 30 is mounted on the top of the housing 1, and the document is automatically directed to the reading position of the reading device ES in conjunction with the image reading means 13 of the image forming device 20. The image information of the document can be read by the reading device ES.
[0045]
The entire ADF 30 is covered with an ADF casing 31, and the ADF 30 is provided with a document table 32 and a paper discharge unit 33 outside the ADF casing 31.
[0046]
On the document placement table 32, a plurality of documents WP with the document surface (front surface) of the first page at the top is placed. The placed document WP is conveyed to the reading position by the document conveying device, read by the reading device ES, and discharged to the paper discharge unit 33.
[0047]
For example, in the case of a document WP in which an index document is placed on the top of a plurality of document bundles composed of a plurality of pages, the document is similarly transported, read, and discharged.
[0048]
An index document describes a summary of the contents of a document bundle, and generally, a thick paper having a protruding portion called a tab is used as an index sheet.
[0049]
The document conveying device is operated in conjunction with the control means EC of the image forming apparatus 20 by a drive control circuit (not shown).
[0050]
The document conveying device swings in the direction of arrow J and feeds the document WP placed on the document placing table 32 one by one, temporarily stops the fed document WP, and sequentially conveys the document WP at appropriate timing. A conveying roller (A) 35 composed of a pair of rollers for rotation, a conveying roller (B) 36 which is provided opposite to a roller 37 which is rotated by being driven, and which is rotated while being sandwiched between the document WP and the roller 37, A document roller WP that has been conveyed is sandwiched between rollers 37 and a reading roller 38 that conveys the document WP to a reading position so that it can be read by the reading device ES, and a pair of paper that conveys the read document WP in the direction of arrow L The paper discharge roller 39, the reversing member 40 for conveying the document WP in the K direction so that the image information on the back side can be read, and the document detection sensor for detecting the conveyed document WP and outputting detection information. It is composed of S1 and the like.
[0051]
The document detection sensor S1 includes a photo sensor, a mechanical switch, and the like, and is disposed between the transport roller (A) 35 and the transport roller (B).
[0052]
The document detection sensor S1 detects the leading edge or the trailing edge of the document WP in the transport direction, detects the completion of transport of the document WP, and detects the number of transported documents (also referred to as the number of pages). Information and conveyance start information for starting conveyance of the next document WP are obtained.
[0053]
In the case of an index document, a projection called a tab is provided at the side edge of the index sheet. Therefore, the type of document for detecting the presence or absence of this tab and determining whether the document is an index document or another document Information can be obtained as needed.
[0054]
Note that the count information, the conveyance start information, the document type information, and the like detected by the document detection sensor S1 are stored in the storage unit 160 via the information control circuit 120 described later during reading, and information control is performed during image formation. The circuit 120 reads out the stored information and controls to form an image on the index sheet when, for example, the page number of the index document matches the number of pages (number of pages) for the stored image data. It is used as information to do.
[0055]
Although details are omitted, the conveyance operation includes a one-side mode in which image information on only one side of the original WP is read and a double-side mode in which image information on both front and back sides of the original WP is read. By swinging to the center, reading in a single-sided mode and a double-sided mode is possible.
[0056]
The circuit configuration of the image forming apparatus according to the present invention will be described with reference to FIG.
Reference numeral 100 denotes a configuration of various units and circuits of the entire image forming apparatus 20, and 110 is a CPU that controls the entire image forming apparatus 20, and programs and programs in various modes for controlling the image forming apparatus 20. Data necessary for execution is stored in advance.
[0057]
An information control circuit 120, an image processing circuit 140, a drive control circuit 150, a power supply circuit 400, and the like are connected to the CPU 110. These circuits constitute the control means EC shown in FIG. 1 so that the entire image forming apparatus 20 can be controlled.
[0058]
The information control circuit 120 is connected to the external information device 500 via an interface (I / F) 130 according to an instruction from the CPU 110 to set image information such as characters and images, density and magnification necessary for image formation, and the like. Information is input as JOB information in units of 1 JOB, which is one printing unit, and stored in the storage unit 160.
[0059]
The setting information stored in the storage unit 160 is output to the image processing circuit 140, the drive control circuit 150, the display unit 300, or the like.
[0060]
The information control circuit 120 is necessary for the operation of circuits and various means including the image processing circuit 140 and the drive control circuit 150 in addition to JOB information including image information and setting information input from the external information device 500. Input / output and operation input of data (also referred to as JOB data) related to the instruction information, for example, the conveyance speed according to the type of the transfer material P, the time required for the conveyance speed change setting, and the like. It has a function of smoothly and appropriately transmitting various information input by the means 200 to each circuit and various means of the image forming apparatus so as not to hinder the operation of the image forming apparatus.
[0061]
Further, in the embodiment of the present invention, the information control circuit 120 reads the number of originals detected by the original detection sensor S1 in order to read an original of a bundle of originals in which an index original and a text original are mixed to form an image. Counting information indicating that the document has been conveyed, conveyance start information indicating completion of conveyance of the previously conveyed document, and the like are input.
[0062]
For example, when reading a document, the number of documents (also referred to as the number of pages) is stored in the storage unit 160, or similarly, stored as page number information of an index document.
[0063]
When the image is formed, the information stored in the storage unit 160 is read out. When the page number of the index document matches the page number of the document, the index is based on the image data stored corresponding to the page number. An image is formed on a sheet. At this time, the information control circuit 120 also has a function as a determination unit that determines whether or not the page number of the index document matches the number of pages of the document.
[0064]
The external information device 500 is mainly a computer or an Internet server, but in some cases, it can output other image forming apparatuses on a local area network (LAN), a digital camera, or measured information. Information equipment such as a measuring device is assumed.
[0065]
The interface (I / F) 130 is information exchange means, and is configured to be connected to the above-described computer, other image forming apparatuses, and external information equipment 500 such as an Internet server via various networks.
[0066]
The operation input unit 200 is an input device provided on the control panel CP of the image forming apparatus 20. The liquid crystal display device DP, keyboard KB, start button SK, and the like provided with the touch panel described above are assumed.
[0067]
For example, by operating the keyboard KB, the number and type of transfer materials to be output (for example, index paper, thick paper, plain paper, thin paper, recycled paper, OHP sheet, etc.), enlargement / reduction magnification, output image density, etc. Setting information can be entered.
[0068]
In addition, the operation input unit 200 may be an input unit for setting various operation modes of the image forming apparatus 20 depending on circumstances.
[0069]
In particular, in the embodiment of the present invention, as will be described in detail later, the first image formation mode in which image formation is performed at a conveyance speed corresponding to the transfer material, and the image formation is performed at the lowest conveyance speed in the JOB data. This is an input device for setting and selecting the second image forming mode.
[0070]
The display means 300 is configured by the above-described liquid crystal display device, or a display device DP in which a touch panel or the like is incorporated in a liquid crystal display unit.
[0071]
The display means 300 displays an operation procedure when inputting information with the operation input means 200, a list display of various information, a display of information stored in the storage means 160, a status display during operation of the image forming apparatus, and a warning display. Etc. are displayed.
[0072]
In particular, in the embodiment of the present invention, the image forming times in the first image forming mode and the second image forming mode are calculated and compared, and the image forming mode with the shorter image forming time is selected. The image forming time calculated at that time, the selected image forming mode, and the like are displayed.
[0073]
The image processing circuit 140 digitally converts the image information of the document read by the image reading unit 13 in accordance with an instruction from the CPU 110 and stores the image information in the storage unit 160 as image data or the image data stored in the storage unit 160. This is a circuit for converting data, signals and the like suitable for the image forming method of the image forming means 11 when the image forming means 11 forms an image.
[0074]
The drive control circuit 150 operates the image forming unit 11, the image reading unit 13, the paper supply / discharge unit 14, the ADF 30, and the like according to instructions from the CPU 110 at an appropriate timing based on a preset operation mode. This is a circuit for performing the operation.
[0075]
The storage unit 160 stores JOB information and JOB data including image data necessary for forming an image and setting conditions for controlling the image forming apparatus 20, and information such as programs for various setting modes. It has become.
[0076]
Note that the JOB information and JOB data are defined as follows in the embodiment of the present invention.
[0077]
For example, when the image forming apparatus 20 is a copying machine, the JOB information is set based on the image information of the original, selects a single-sided or double-sided mode, selects a paper feed tray, selects the number of copies, and print density. Is a series of print data determined by making output settings and instructing the start of copying, such as selection of individual jobs (JOB). A print data group corresponding to the above is also called 1 JOB.
[0078]
Similarly, when the image forming apparatus is a printer, a series of print data groups transmitted from the external information device 500 is called JOB information, and a print data group corresponding to one print instruction is called 1 JOB. The handling of JOB information and JOB data for each JOB is called 1 JOB unit.
[0079]
Note that the JOB data relates to data associated with the JOB information such as, for example, a conveyance speed according to a transfer material, a change time associated with a conveyance speed change process, or a control item for executing an image forming operation. The control value data related to the conveyance speed.
[0080]
The minimum conveyance speed in the JOB data is the slowest conveyance speed set according to the type of transfer material among the transfer materials to be used. For example, three types of transfer materials and transfer are included in the JOB data. When data of three types of conveyance speeds corresponding to the type of material is stored, it means the slowest conveyance speed among the three types of conveyance speeds.
[0081]
Therefore, the storage unit 160 stores JOB information and JOB data for each JOB, that is, in units of 1 JOB (also simply referred to as JOB units).
[0082]
As shown in FIG. 1, the image forming unit 11 includes a photosensitive drum 5, a charging unit 6, a developing unit 7, a transfer separating unit 8, a cleaning unit 9, a fixing unit 10, and the like, and is operated by a drive control circuit 150. Is done.
[0083]
Based on the image data read by the image reading means 13 and stored in the storage means 160, an image is formed on the photosensitive drum 5 under the control of JOB information or JOB data, and the image is transferred to the plain paper P or the index paper IP. And record it.
[0084]
As shown in FIG. 1, the image reading unit 13 includes a reading optical system and a reading device ES. The image information of the document that is operated by the drive control circuit 150 and conveyed to the reading position is read by the reading device ES, and the read image information is converted into digital image data by the image processing circuit 140, for example, and stored. The information is stored in the means 160.
[0085]
As shown in FIG. 1, the paper supply / discharge unit 14 includes a paper supply cassette 12 that stores index paper IP and plain paper P, and a paper supply / discharge conveyance device.
[0086]
According to an instruction from the CPU 110, the paper supply / discharge transport device compares the number of pages of the original with the page number of the index original by the information control circuit 120 to select the index paper IP or the plain paper P, and then the drive control circuit. 150 through. The index paper IP or plain paper P selected from the paper feed cassette 12 is fed and conveyed toward the photosensitive drum 5 at an appropriate timing, and the index paper IP or plain paper P on which an image is formed is delivered to the paper discharge tray 3. The paper is transported.
[0087]
As shown in FIG. 1, the automatic document feeder (ADF) 30 is a device that automatically conveys documents placed on a document placing table 32 to a reading position one by one by a document conveying device. The CPU 110 operates in cooperation with the drive control circuit 150 according to the instruction of the CPU 110.
[0088]
The document detection sensor S1 provided in the ADF 30 detects the leading edge or the trailing edge of the conveyed document and acquires information related to the document conveyance.
[0089]
For example, when transporting a document, it is determined whether the count information for detecting the number of pages (number of pages) of the transported document WP, transport start information for starting transport of the next document WP, and whether it is an index document or another document. Document type information to be acquired is acquired and stored in the storage unit 160 via the information control circuit 120.
[0090]
When the image is formed, the information control circuit 120 reads out the stored information and compares the page number of the index document with the number of pages of the document. If they match, an image is formed on the index sheet IP. In addition, when they do not coincide with each other, the information is used as information for operating the image forming unit 13 and the paper supply / discharge unit 14 through the drive control circuit 150 so as to form an image on the plain paper P.
[0091]
When a power switch (not shown) is turned on by a user's operation, the power supply circuit 400 is appropriately energized from the power source to the entire image forming apparatus. When the power switch is shut off, the power supply is shut off. It has become so.
[0092]
Even when the power switch is turned on, for example, in the power saving mode in which the image forming apparatus is in a standby state, only energization necessary for storing the storage contents of the temporary memory or the like is instructed by the CPU 110. And other energization such as a heater of the fixing means is cut off.
[0093]
Next, the relationship between the transfer material and the fixing device according to the present invention will be described.
Examples of transfer materials used in image forming apparatuses include tab paper (index paper), thick paper, plain paper, thin paper, recycled paper, and OHP sheet. There are thin paper, plain paper, and cardboard.
[0094]
As a rough guide, thin paper refers to paper of less than 60 (g / square meter), for example, dictionary paper corresponds to this. Plain paper refers to paper of about 60 to 200 (g / square meter), for example, commonly used copy paper. The cardboard refers to a paper of 200 (g / square meter) or more, for example, a public postcard and a general tab paper (index paper).
[0095]
Further, the smoothness of the paper surface is also an approximate guide, but the smoothness can be classified into three levels of high, normal, and low.
[0096]
Examples of high smoothness include coated paper whose surface is coated. Examples of ordinary smoothness include commonly used copy paper. Examples of low smoothness include newspaper, book paper, and embossed paper that has been processed to be uneven.
[0097]
As described above, the thickness and smoothness are different depending on the type of transfer material, and when the thickness and smoothness are different, for example, the paper having a large thickness or the paper having a low smoothness has a small thickness or Compared to a toner having a high smoothness, it is necessary to give a larger heat capacity in order to fix the toner image with the fixing device.
[0098]
In the case where a transfer material having a large heat capacity and a small transfer material to be given in the fixing process are alternately used due to the thick paper or the low smoothness of the paper surface, in the fixing device, the transfer material is simply When the conveyance speed is changed, there is a problem that the control of the entire image forming process is greatly affected, and the productivity of the image forming apparatus is deteriorated as described above.
[0099]
Therefore, as a result of examining the relationship between the heat capacity of the transfer material and the conveyance speed in the fixing device, when a transfer material having a large heat capacity (thickness or low smoothness) is conveyed quickly, fixing under occurs, but the heat capacity is small. It has been found that even if the transfer material (thickness or high smoothness) is conveyed slowly and given a large amount of heat, no significant problem occurs. It has been found that if fixing loss or the like occurs due to an excessive amount of heat, the conveyance speed may be adjusted by slightly lowering the fixing temperature.
[0100]
That is, when a transfer material having a large heat capacity (for example, index paper IP) and a small transfer material (for example, plain paper P) are used alternately for output, the transfer speed of the transfer material having a large heat capacity has a smaller heat capacity. Since the transfer speed of the transfer material is slower than that of the transfer material, it was found that the transfer material having a large heat capacity and the transfer material having a small heat capacity can be fixed under the same fixing conditions by using the transfer speed of the transfer material having a large heat capacity.
[0101]
In other words, when information to be output by alternately using a transfer material having a large heat capacity and a transfer material having a small heat capacity is stored in one JOB information for image formation, the JOB data accompanying the JOB information includes The transfer speed for the transfer material having a large heat capacity and the transfer material having a small heat capacity are stored. For the transfer material having a large heat capacity, a transfer speed slower than the transfer speed of the transfer material having a small heat capacity is stored.
[0102]
Therefore, when calculating the image forming time, a transport speed and a minimum transport speed (also referred to as a minimum transport speed) corresponding to the type of transfer material are required. The minimum transport speed is included in one JOB information. In this case, the transfer speed of the transfer material having a large heat capacity is set in the JOB data because the lowest transfer speed is set among a plurality of transfer speeds corresponding to the type of transfer material included in the transfer data. The minimum transport speed is set.
[0103]
Therefore, by adopting such a fixing method, when image formation is performed, an image is formed by changing the conveyance speed according to the transfer material, and an image is formed at the minimum conveyance speed in the JOB data. Thus, it has been found that it is good to compare the image forming times and perform image formation by the image forming method having a shorter time, so that the image can be formed without reducing the productivity.
[0104]
Next, an image forming operation according to the present invention will be described in the case where a transfer material having a large heat capacity and a transfer material having a small heat capacity are alternately used for output.
[0105]
In the embodiment of the present invention, taking into account that image formation of a document bundle in which an index document and a text document are mixed may be performed as described above, an index sheet IP ( Plain paper P as a small transfer material.
[0106]
Further, the fixing temperature TC is set to 200 ° C., the plain paper transport speed VA is 500 mm / sec, the thick paper transport speed VB is 300 mm / sec, the transfer material transport interval (also referred to as a sheet interval) PC is 100 mm, and the transport speed is switched. The setting change time R required for 10 seconds was set to 10 seconds.
[0107]
Then, the image formation time is calculated and compared when 10 sheets of A4 (vertical 297 mm × width 210 mm) plain paper and 10 sheets of A4 thick paper are output alternately. In addition, A4 plain paper and A4 thick paper shall be conveyed in the horizontal direction.
[0108]
(1) An image forming time T1 required for completing all outputs when the conveyance speed is changed according to the transfer material is obtained.
[0109]
If TA is the image forming time for plain paper, TB is the image forming time for thick paper, and TR is the total of the setting change times R, then T1 = TA + TB + TR.
[0110]
(A) The total transport distance of plain paper is LA, and TA is obtained.

(B) The previous transport amount of cardboard is LB, and TB is obtained.
[0111]

(C) The total TR of setting change times R is obtained.
[0112]
TR = R × 19 times = 10 sec × 19 = 190 sec
(D) Obtain T1 = TA + TB + TR.
[0113]

(2) The image forming time required to complete all outputs when the fixing temperature TC is 200 ° C., the minimum transport speed VC in the JOB data is 300 mm / sec, and a total of 20 sheets of plain paper and cardboard are transported. Find T2.
[0114]
(E) The total transport distance L2 between plain paper and cardboard is obtained.

(F) An image forming time T2 when the image is conveyed at the lowest conveyance speed in the JOB data is obtained.
[0115]

(3) Compare T1 and T2.
[0116]
T1 = 206.2 sec> T2 = 20.3 sec
In this case, when all the outputs are performed at the lowest conveyance speed (also referred to as the minimum conveyance speed) in the JOB data, the image formation time until completion of all the output is shortened. It can be seen that productivity improves.
[0117]
Accordingly, the first image forming mode in which image formation is performed at a conveyance speed corresponding to the type of transfer material and the second image formation mode in which image formation is performed at the minimum conveyance speed in the JOB data are performed to perform image formation. At this time, the first image formation time in the first image formation mode and the second image formation time in the second image formation mode are calculated and compared, and image formation with the shorter image formation time is performed. If image formation is performed in the mode, an image forming apparatus with high productivity can be provided.
[0118]
Next, the change of the control value of the control target item related to image formation when the transfer material conveyance speed is changed will be described.
[0119]
When the conveyance speed of the transfer material is changed, for example, the control value of the control target item shown below must be changed along with the change.
[0120]
However, if all the control values of the control target items for the transfer speed of the transfer material are stored in the storage unit 160, a huge amount of data is obtained. Therefore, for example, this problem is obtained by obtaining a change in the changed conveyance speed with respect to the conveyance speed corresponding to the type of transfer material, and obtaining a control value for the changed conveyance speed by calculation based on the change. Can be solved.
[0121]
Specifically, in the embodiment of the present invention, for example, the conveyance speed of the frequently used plain paper and the control value are stored, and the linear speed ratio is obtained based on these values, The control value after changing the conveyance speed was obtained.
[0122]
For example, when the transfer speed (also referred to as linear speed) A of the transfer material A is 500 mm / sec and the changed linear speed B is 300 mm / sec, the change in the linear speed B relative to the linear speed A (also referred to as the linear speed ratio). C) C = B / A = 300 (mm / sec) / 500 (mm / sec) = 0.6.
[0123]
Therefore, in the case of the linear velocity B, the change in the control value of the control target item (1) to (7) below is a value obtained by adding the linear velocity ratio C (0.6) to the control value in the case of the linear velocity A. It becomes as follows.
<Data>

The control target items will be described.
(1) The charging current is changed by the change in the linear speed because the amount of charge to be applied to the photosensitive drum per unit time changes as the linear speed changes.
(2) The charging grid voltage does not change even if the linear velocity changes because the charging potential of the photosensitive drum does not change even if the linear velocity changes.
(3) Since the developing sleeve rotation speed needs to make the speed ratio between the photosensitive drum and the developing sleeve constant, if the linear speed changes, it changes by the change in the linear speed.
(4) The transfer current is changed by the change in the linear speed because the amount of charge to be applied to the transfer paper per unit time changes as the linear speed changes.
(5) The separation direct current (DC) current is changed by the change in the linear velocity because the amount of charge to be applied to the transfer paper per unit time changes as the linear velocity changes.
(6) Since the separated alternating current (AC) current is a fixed value output, it may not be changed even if the linear velocity changes.
(7) The target fixing temperature does not need to be changed if it does not cause problems such as hot offset (fixing omission) or fixing under. However, it may be necessary to change depending on conditions such as paper type and environment.
[0124]
In other words, when the transport speed is changed, the linear speed ratio is obtained as described above, and the control value of the control target item set based on the linear speed before the change is multiplied by the linear speed ratio. The control value of the control target item corresponding to the subsequent linear velocity can be easily obtained.
[0125]
Therefore, when performing control to change the transport speed, the above-described calculation may be performed, and it is not necessary to store the control values of the control target items corresponding to all transport speeds in the storage means. There is no need to increase the storage capacity of the.
[0126]
Further, since the calculation for obtaining the control value may be a simple calculation, the calculation program is simple and the control circuit and the control operation need not be complicated.
[0127]
Next, the procedure of the image forming operation according to the present invention will be described with reference to FIG. In the description, it will be described in detail with reference to FIGS. 1 and 2 as appropriate.
[0128]
(ST1)
The first step is to input JOB information. For example, when the image forming apparatus is a printer, the information control circuit 120 inputs data as JOB information and JOB data from the external information device 500 via the interface (I / F) 130 according to an instruction from the CPU 110, and the storage unit 160. Is remembered.
[0129]
Similarly, when the image forming apparatus is a copying machine, JOB information and JOB data input from the external information device 500 via the image reading unit 13 or the interface (I / F) 130 are stored in the storage unit 160. Is done.
[0130]
When JOB information and JOB data are input in units of 1 JOB and stored in the storage means 160, the process proceeds to ST2.
[0131]
(ST2)
In this step, it is determined whether or not an image is formed by changing the transfer material. In response to an instruction from the CPU 110, when the information control circuit 120 reads out one JOB information from the storage means 160 to execute image formation, each JOB included in the JOB information is searched, and the JOB information is included in the JOB information. If there is a job for changing the transfer material to perform image formation, the process proceeds to ST3, and if the image formation is performed without changing the transfer material, the process jumps to ST11.
[0132]
(ST3)
In this step, it is determined whether the first copy passes through this step. When performing image formation, if the CPU 110 detects that the information control circuit 120 is the first copy according to an instruction from the CPU 110, the process proceeds to ST4, and if it is any other copy, the process jumps to ST6.
[0133]
(ST4)
In this step, it is determined whether or not the first sheet passes through this step. When performing image formation, if it is detected by the instruction of the CPU 110 that the information control circuit 120 is the first sheet, the process proceeds to ST5, and if it is any other number, the process jumps to ST6.
[0134]
(ST5)
Based on the JOB information and the JOB data, a first image formation time (referred to as A method) in the first image formation mode and a second image formation time (referred to as B method) in the second image formation mode are calculated. It is a step to do.
[0135]
In accordance with an instruction from the CPU 110, the information control circuit 120 calculates the image forming times of the A method and the B method based on the JOB information and JOB data read from the storage unit 160.
[0136]
Since the calculated image forming times of the A method and the B method are stored in the storage unit 160, even when one piece of JOB information is formed, that is, when a plurality of copies are formed. The calculation only needs to be executed once.
[0137]
There are two methods for the calculation. One is a method of calculating in units of JOB. In this case, since the image formation time can be calculated in consideration of all JOBs, the calculation is somewhat complicated, but there is an advantage that an accurate comparison can be made when comparing the image formation times.
[0138]
The other is a method of calculating in units of a fixed number of pages, which has the advantage that it can be easily calculated. However, on the other hand, depending on the setting of a fixed number of pages, for example, errors are likely to occur. Although there is a large difference between the number and the number of output copies, it is not suitable for comparison of image forming times.
[0139]
In other words, when comparing the image forming times, it is necessary to determine whether to compare in units of JOB or in units of a certain number of pages in consideration of these characteristics, and to perform calculation according to this determination. There is.
[0140]
Therefore, it is convenient to set which method is to be compared, for example, to automatically determine and calculate based on the number of copies of JOB information. Further, it is more convenient to be able to set which method is to be compared in JOB units by the control panel CP, or to set the number of pages in a certain number of pages.
[0141]
(ST6)
This is a step of comparing the image forming times of the A method and the B method. In response to an instruction from the CPU 110, the information control circuit 120 compares the image formation times of the A method and the B method obtained in step ST5. If the A method image formation time is short, the process proceeds to ST7, and if the B method image formation time is short, the process jumps to ST10.
[0142]
(ST7)
This is a step for obtaining and setting the control value of the control item according to the transport speed in the case of the A method. As described above, the control value of the control item related to the conveyance speed is obtained by obtaining the linear speed ratio with respect to the conveyance speed of the transfer material before the change and multiplying the obtained linear speed ratio by the control value before the change. When the information control circuit 120 obtains a control value according to an instruction from the CPU 110, and the obtained control value is set for each related control item such as the drive control circuit 150, the process proceeds to ST8.
[0143]
If the obtained control value is stored in the storage unit 160 in association with the conveyance speed, it is convenient because it can be read out from the storage unit 160 and used as needed without repeating the calculation. is there.
[0144]
Further, instead of the conveyance speed and control value before the change, the conveyance speed and control value corresponding to some preset transfer materials may be selected and used, or frequently used plain paper The conveyance speed and the control value may be used.
[0145]
(ST8)
This is a step of performing an image forming operation by the A method based on JOB information, JOB data, a control value related to the conveyance speed, and the like.
[0146]
In response to an instruction from the CPU 110, the image processing circuit 140 and the drive control circuit 150 cooperate to operate the image forming unit 11, the paper supply / discharge unit 14, and the like to perform an image forming operation. When the image forming operation in the preset image forming unit is completed, the process proceeds to ST9.
[0147]
The preset image forming unit means, for example, a unit for each transfer material or one copy, and it can be set in advance by the control panel CP whether or not to perform image formation. It has become.
[0148]
Accordingly, if the image forming operation for each transfer material is set as an image forming unit, the process proceeds to ST9 when the image forming operation for one sheet is completed, and if the image forming operation for each copy is set, When the image forming operation for one copy is completed, the process proceeds to ST9.
[0149]
(ST9)
This is a step for determining whether or not all JOBs have been completed. The number of output copies can be set in advance by the control panel CP, and the information control circuit 120 determines whether or not the set number of output copies matches the number of output copies according to an instruction from the CPU 110. Yes.
[0150]
When the set number of output copies matches the number of output copies, the image forming operation is terminated, and when they do not match, the process jumps to ST2.
[0151]
(ST10)
This is a step for obtaining and setting a control value of a control item according to the conveyance speed in the case of the B method. Similar to the A method, the information control circuit 120 obtains a control value of a control item related to the conveyance speed in accordance with an instruction from the CPU 110, and the obtained control value is set for each related control item such as the drive control circuit 150. And proceed to ST11.
[0152]
The obtained control value is stored in the storage unit 160 in association with the transport speed, as in the A method.
[0153]
(ST11)
This is a step of performing an image forming operation by the B method based on the JOB information and JOB data, the obtained control value, and the like.
[0154]
Similar to the A method, according to an instruction from the CPU 110, the image processing circuit 140 and the drive control circuit 150 cooperate to operate the image forming unit 11, the paper supply / discharge unit 14, and the like to perform an image forming operation. When the image forming operation in the preset image forming unit is completed, the process proceeds to ST9.
[0155]
(ST12)
This is a step of performing an image forming operation based on a conveyance speed and a control value corresponding to the transfer material. Since there is no JOB for changing the transfer material in the JOB information, an image forming operation is performed by setting a control value corresponding to the conveyance speed for the only transfer material set in the JOB information. When the image forming operation in the preset image forming unit is completed, the process proceeds to ST9.
[0156]
In this case, if the transfer material is frequently used as a general-purpose transfer material, such as plain paper, the transfer speed and control value of the transfer material are tabulated in advance for several frequently used transfer materials. If stored in the storage means 160, the conveyance speed and control value can be set simply by setting the type of transfer material.
[0157]
As described above, the control procedure of the image forming apparatus according to the present invention has been described. However, according to the present invention, when the transfer material is fixed in the fixing device, the conveyance speed set according to the type of the transfer material is different. In this case, the image formation time when the image formation is performed at the conveyance speed corresponding to the type of transfer paper or the lowest conveyance speed in the JOB data is compared. Since the formation is performed, the productivity can be improved without deteriorating the image quality.
[0158]
As an example of a transfer material with a large heat capacity and a transfer material with a small heat capacity, the case where index paper and plain paper are mixed has been described as an example, but transfer including a combination of transfer paper with high smoothness and transfer paper with low smoothness is also described. The combination of papers is not limited to this combination, and it is always possible to improve productivity by comparing the image formation times in other combinations, and performing image formation in the image formation mode with the shorter image formation time. Can do.
[0159]
In addition, it is possible to easily perform an image formation time calculation in a unit of a certain number of pages and perform a simple comparison, or to perform an accurate comparison by calculating an image formation time with information of one JOB unit which is one printing unit. Since it did in this way, according to JOB information, since it can compare by an optimal system, productivity can be improved.
[0160]
Furthermore, even if the conveyance speed is changed, each control value can be easily obtained by obtaining the conveyance speed ratio, so it is not necessary to store all the control values for the conveyance speed, and the storage capacity of the storage means is reduced. Since it can be made small, the control circuit can be configured with an inexpensive one, and the productivity can be improved.
[0161]
【The invention's effect】
The present invention compares the image formation times when image formation is performed at a conveyance speed corresponding to the type of transfer material and image formation is performed at the minimum conveyance speed in the JOB data. Since image formation is performed, an image forming apparatus capable of always forming an image with high productivity can be provided.
[0162]
Furthermore, even if the conveyance speed is changed, each control value can be easily obtained by obtaining the conveyance speed ratio, and the control value related to image formation is controlled with an appropriate control value, and fixing failure may occur. And an image forming apparatus capable of forming an image with high productivity.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus.
FIG. 2 is a block diagram illustrating a circuit configuration of the image forming apparatus.
FIG. 3 is a flowchart illustrating a control procedure of the image forming apparatus.
[Explanation of symbols]
1 housing
2 Bypass tray
3 Output tray
4 Laura
5 Photosensitive drum
6 Charging means
7 Development means
8 Transfer separation means
9 Cleaning means
10 Fixing means
11 Image forming means
12 Paper cassette
13 Image reading means
14 Feeding and discharging means
20 Image forming apparatus
30 Automatic document feeder
31 ADF housing
32 Document placement table
33 Output section
34 Feed roller
35 Conveying roller (A)
36 Conveying roller (B)
37 Laura
38 Reading roller
39 Paper discharge roller
40 Reversing member

Claims (5)

In an image forming apparatus provided with a control unit capable of changing the transfer speed of a transfer material according to the type of transfer material to cause image formation,
JOB information storage means for storing JOB information relating to image formation of a document in JOB units, and the JOB data for storing the conveyance speed according to the type of transfer material and the change setting time for changing the conveyance speed as JOB data. A data storage unit, a first image forming mode in which image formation is performed at the conveyance speed according to the type of transfer material, and a second image formation mode in which image formation is performed at the minimum conveyance speed in the JOB data. The control means, when performing image formation based on the JOB information and the JOB data, a first image formation time in the first image formation mode and a second image in the second image formation mode. An image forming apparatus comprising: calculating and comparing a forming time and performing image formation in the image forming mode having a shorter image forming time. The image forming apparatus according to claim 1, wherein the control unit calculates the first and second image forming times in units of one JOB. The image forming apparatus according to claim 1, wherein the control unit calculates the first and second image forming times in a unit of a certain number of pages. When image formation is performed at another transport speed different from the transport speed according to the type of transfer material, the control unit transports the transport speed at another transport speed with respect to the transport speed according to the type of transfer material. A speed ratio is obtained, and image formation is performed with a second control value obtained by multiplying the first control value when the image formation is performed at the transport speed according to the type of transfer material by the transport speed ratio. The image forming apparatus according to claim 1, wherein the image forming apparatus is performed. 5. The control device according to claim 4, wherein the first and second control values are at least one control value of a charging output for image formation, a developing sleeve rotation speed, a transfer output, a separation output, and a fixing target temperature. The image forming apparatus described.

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