BR112017020829A2 - aparelho de suprimento de líquido e aparelho de consumo de líquido - Google Patents

aparelho de suprimento de líquido e aparelho de consumo de líquido

Info

Publication number
BR112017020829A2
BR112017020829A2 BR112017020829-6A BR112017020829A BR112017020829A2 BR 112017020829 A2 BR112017020829 A2 BR 112017020829A2 BR 112017020829 A BR112017020829 A BR 112017020829A BR 112017020829 A2 BR112017020829 A2 BR 112017020829A2
Authority
BR
Brazil
Prior art keywords
ink
liquid
tank
tank unit
cylinder portions
Prior art date
Application number
BR112017020829-6A
Other languages
English (en)
Japanese (ja)
Inventor
Kimura Naomi
Kanaya Munehide
Original Assignee
Seiko Epson Corporation
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 Seiko Epson Corporation filed Critical Seiko Epson Corporation
Publication of BR112017020829A2 publication Critical patent/BR112017020829A2/pt

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17503Ink cartridges
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17503Ink cartridges
    • B41J2/17506Refilling of the cartridge
    • B41J2/17509Whilst mounted in the printer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17503Ink cartridges
    • B41J2/17513Inner structure
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17503Ink cartridges
    • B41J2/1752Mounting within the printer
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17503Ink cartridges
    • B41J2/1752Mounting within the printer
    • B41J2/17523Ink connection
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17503Ink cartridges
    • B41J2/17553Outer structure
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17566Ink level or ink residue control
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J29/00Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for
    • B41J29/02Framework
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J29/00Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for
    • B41J29/12Guards, shields or dust excluders
    • B41J29/13Cases or covers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17566Ink level or ink residue control
    • B41J2002/17573Ink level or ink residue control using optical means for ink level indication
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/175Ink supply systems ; Circuit parts therefor
    • B41J2/17566Ink level or ink residue control
    • B41J2002/17579Measuring electrical impedance for ink level indication

Landscapes

  • Ink Jet (AREA)

Abstract

trata-se de uma técnica que aprimora a precisão de detecção de um líquido contido em uma unidade de tanque. a impressora 10 é dotada de uma unidade de tanque 40a. a unidade de tanque 40a inclui uma pluralidade de tanques de tinta 43a e uma pluralidade de porções de cilindro de tinta 46a. cada uma dentre a pluralidade de porções de cilindro de tinta 46a é conectada a um dos tanques de tinta 43a correspondentes por um tubo 47, tal como para induzir a tinta contida no tanque de tinta correspondente 43a a fluir na porção de cilindro de tinta 46a. cada uma das porções de cilindro de tinta 46a é dotada de um par de pinos de terminal 96a e 96b que é usado para detecção de tinta. uma área em corte horizontal da porção de cilindro de tinta 46a em uma posição de altura onde se proporciona o par de pinos de terminal 96a e 96b é menor que uma área em corte horizontal do tanque de tinta 43a em uma posição de altura correspondente.
BR112017020829-6A 2015-03-31 2016-03-30 aparelho de suprimento de líquido e aparelho de consumo de líquido BR112017020829A2 (pt)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2015-070897 2015-03-31
JP2015070897A JP6657583B2 (ja) 2015-03-31 2015-03-31 液体供給装置および液体消費装置
PCT/JP2016/001845 WO2016157901A1 (ja) 2015-03-31 2016-03-30 液体供給装置および液体消費装置

Publications (1)

Publication Number Publication Date
BR112017020829A2 true BR112017020829A2 (pt) 2018-07-03

Family

ID=57004400

Family Applications (1)

Application Number Title Priority Date Filing Date
BR112017020829-6A BR112017020829A2 (pt) 2015-03-31 2016-03-30 aparelho de suprimento de líquido e aparelho de consumo de líquido

Country Status (8)

Country Link
US (1) US10195860B2 (pt)
JP (1) JP6657583B2 (pt)
KR (1) KR20170120177A (pt)
CN (2) CN107405927A (pt)
BR (1) BR112017020829A2 (pt)
PH (1) PH12017501709A1 (pt)
TW (1) TW201637885A (pt)
WO (1) WO2016157901A1 (pt)

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6961946B2 (ja) * 2017-01-31 2021-11-05 ブラザー工業株式会社 供給装置
US10493765B2 (en) 2017-03-27 2019-12-03 Brother Kogyo Kabushiki Kaisha Liquid cartridge capable of reducing leakage of liquid from liquid storage chamber
JP6825445B2 (ja) * 2017-03-27 2021-02-03 セイコーエプソン株式会社 収容ユニットおよび収容ユニットの液体量管理方法
JP6942988B2 (ja) 2017-03-27 2021-09-29 ブラザー工業株式会社 液体カートリッジ及びシステム
JP6950228B2 (ja) 2017-03-27 2021-10-13 ブラザー工業株式会社 液体カートリッジ及びシステム
JP2018161874A (ja) 2017-03-27 2018-10-18 ブラザー工業株式会社 液体カートリッジ
JP7031132B2 (ja) 2017-03-27 2022-03-08 ブラザー工業株式会社 液体カートリッジ及びシステム
WO2019012786A1 (ja) * 2017-07-12 2019-01-17 セイコーエプソン株式会社 液体収容容器
EP3437877B1 (en) * 2017-07-31 2021-03-17 Brother Kogyo Kabushiki Kaisha Liquid cartridge and system therefor
JP7077612B2 (ja) * 2017-12-27 2022-05-31 ブラザー工業株式会社 液体排出装置
JP7035647B2 (ja) * 2018-03-12 2022-03-15 ブラザー工業株式会社 システム
JP7063065B2 (ja) * 2018-03-30 2022-05-09 ブラザー工業株式会社 システム
JP7164455B2 (ja) * 2019-01-31 2022-11-01 理想科学工業株式会社 容器
JP7236280B2 (ja) * 2019-01-31 2023-03-09 理想科学工業株式会社 タンク
JP7247624B2 (ja) * 2019-02-12 2023-03-29 セイコーエプソン株式会社 印刷装置
JP7305973B2 (ja) * 2019-02-12 2023-07-11 セイコーエプソン株式会社 印刷装置
JP7298173B2 (ja) * 2019-02-12 2023-06-27 セイコーエプソン株式会社 印刷装置
JP7363333B2 (ja) 2019-10-10 2023-10-18 セイコーエプソン株式会社 液体収容容器、及び液体噴射装置
JP2022179914A (ja) * 2021-05-24 2022-12-06 セイコーエプソン株式会社 記録装置、および液体収容体
JP2023083127A (ja) * 2021-12-03 2023-06-15 ブラザー工業株式会社 タンクユニット、ヘッドシステム、インク供給システム、印刷システム、及び印刷方法

Family Cites Families (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5924676A (ja) * 1982-07-31 1984-02-08 Sharp Corp インクジェットプリンタの気泡除去装置
DE3428434C2 (de) * 1983-08-02 1995-09-14 Canon Kk Druckvorrichtung
JPH07106637B2 (ja) * 1983-08-02 1995-11-15 キヤノン株式会社 記録装置
JPS61195848A (ja) * 1985-02-25 1986-08-30 Ricoh Co Ltd インクジエツト記録装置
JPS62156963A (ja) * 1985-12-28 1987-07-11 Canon Inc 記録装置
JPH05340791A (ja) * 1992-06-11 1993-12-21 Canon Inc 液面検知手段およびインクジェット記録装置
JPH08281966A (ja) * 1995-04-13 1996-10-29 Matsushita Electric Ind Co Ltd インクジェット記録装置及びそのインク残量検知方法
JPH09145451A (ja) 1995-11-16 1997-06-06 Brother Ind Ltd 残量検出装置
JPH10230623A (ja) * 1997-02-21 1998-09-02 Hitachi Koki Co Ltd 加熱溶融形インクを用いたインクジェットプリンタの気泡除去装置およびその方法
JPH11192720A (ja) * 1998-01-05 1999-07-21 Seiko Epson Corp インクジェット式記録装置、インク充填方法、及びインク補給方法
US6293662B1 (en) * 1998-01-19 2001-09-25 Canon Kabushiki Kaisha Ink tank coupling method, ink jet recording apparatus, and ink tank
DE29915256U1 (de) * 1999-08-31 2000-03-09 Sailer Johann Vorrichtung zum Messen des Flüssigkeitsstandes
US6431672B1 (en) * 2001-03-01 2002-08-13 Hewlett-Packard Company Ink container having dual capillary members with differing capillary pressures for precise ink level sensing
JP2004090432A (ja) * 2002-08-30 2004-03-25 Seiko Epson Corp 液体噴射装置、液体噴射装置の液体排出用タンク及び液体噴射装置の液体排出方法
JP2005161637A (ja) * 2003-12-02 2005-06-23 Canon Inc インクジェット記録装置のインク供給機構およびヘッドカートリッジ
US7210771B2 (en) * 2004-01-08 2007-05-01 Eastman Kodak Company Ink delivery system with print cartridge, container and reservoir apparatus and method
JP4384067B2 (ja) * 2004-03-23 2009-12-16 キヤノン株式会社 液体吐出装置および液体処理方法
JP2007160850A (ja) * 2005-12-16 2007-06-28 Sony Corp 液体供給装置
JP2007237552A (ja) * 2006-03-08 2007-09-20 Fuji Xerox Co Ltd 液滴吐出ユニット、及び液滴吐出装置
JP5014006B2 (ja) * 2006-07-19 2012-08-29 キヤノン株式会社 インクカートリッジ
CN101559674A (zh) * 2008-04-18 2009-10-21 株式会社御牧工程 墨供给器及搭载有该墨供给器的喷墨打印机
CN201317161Y (zh) 2008-12-04 2009-09-30 珠海纳思达电子科技有限公司 一种用于喷墨打印机的墨盒
JP5352902B2 (ja) 2009-09-09 2013-11-27 株式会社ミマキエンジニアリング インク残量監視方法
CN202368067U (zh) * 2011-11-14 2012-08-08 常州纳捷机电科技有限公司 便捷墨盒
JP2013151100A (ja) * 2012-01-25 2013-08-08 Seiko Epson Corp 液体供給システムおよび液体噴射装置
JP5834951B2 (ja) * 2012-01-25 2015-12-24 セイコーエプソン株式会社 液体収容容器、および液体消費装置
JP6115029B2 (ja) 2012-05-31 2017-04-19 セイコーエプソン株式会社 液体収容容器の製造方法
JP2014058087A (ja) * 2012-09-14 2014-04-03 Seiko Epson Corp 液体収容体、液体収容体ユニット、液体消費装置、及び液体収容体の製造方法
JP6075097B2 (ja) * 2013-02-07 2017-02-08 セイコーエプソン株式会社 液体容器、液体供給システム
JP6102596B2 (ja) * 2013-07-19 2017-03-29 セイコーエプソン株式会社 インクタンクユニット、インクジェットプリンター、インクタンク
JP2014184594A (ja) * 2013-03-22 2014-10-02 Seiko Epson Corp インク供給システム
JP2014195974A (ja) * 2013-03-29 2014-10-16 ブラザー工業株式会社 液体貯留装置
JP2015044379A (ja) * 2013-08-29 2015-03-12 キヤノン株式会社 液体吐出装置とその制御方法
JP6260212B2 (ja) * 2013-11-12 2018-01-17 セイコーエプソン株式会社 記録装置

Also Published As

Publication number Publication date
WO2016157901A1 (ja) 2016-10-06
PH12017501709A1 (en) 2018-03-19
TW201637885A (zh) 2016-11-01
CN107405927A (zh) 2017-11-28
KR20170120177A (ko) 2017-10-30
US20180111377A1 (en) 2018-04-26
CN111546777B (zh) 2021-12-14
JP6657583B2 (ja) 2020-03-04
US10195860B2 (en) 2019-02-05
CN111546777A (zh) 2020-08-18
JP2016190354A (ja) 2016-11-10

Similar Documents

Publication Publication Date Title
BR112017020829A2 (pt) aparelho de suprimento de líquido e aparelho de consumo de líquido
BR112015027390A2 (pt) Dispositivo de lavagem de ponta de pipeta e método de lavagem de produtos de consumo em laboratório
BR112017009856A2 (pt) dispositivos portáteis para exercício
BR112016025402A2 (pt) recipiente de fluido
CL2018001509A1 (es) Sistema de conexión de viga a columna y soporte resistente al momento que incluye tal sistema.
CO7051014A2 (es) Sistema de enseñanza de idiomas que facilita la implicación del mentor
BR112017009554A2 (pt) dispositivo de inspeção para utilização em um contentor de fluido e dispositivo de inspeção para utilização dentro de um fluido
BR112018007723A2 (pt) bandeja rebaixadora de múltiplas passagens, coluna de transferência de massa, e, método para contato de líquido-vapor
BR102016009088A2 (pt) sistemas desinfetantes
BR112015029801A2 (pt) método e aparelho para a administração de fornecimento de fluido em um sistema de controle de processo
BR112015032667A8 (pt) arranjo multi-acumulador para mecanismo de percussão hidráulica
BR112015032864A2 (pt) método , sistema de computação , e meio de armazenamento legível por computador não transitório armazenando as instruções que mediante a execução causam um sistema
BR112018009099A2 (pt) sistema de tanque para um agente redutor
PL3040101T3 (pl) Urządzenie zasilające do wytwarzania impulsowego strumienia płynu, system aplikacyjny z urządzeniem zasilającym i pamięć czytelna dla komputera
CL2014002632A1 (es) Sistema para entrenamiento de un operador, que incluye una unidad de procesamiento y un medio legible por ordenador con simulador, en que la aplicación de simulador está configurada para generar un ambiente de trabajo simulado, recibir una primera serie de comandos de operación, calcular un camino óptimo, generar un indicador que representa al menos una parte del camino óptimo, mostrar el indicador, recibir segunda serie de comandos, modificar automáticamente el indicador; método; medio legible
BR102015024913B8 (pt) Artigo absorvente
BR112015007711A2 (pt) dispositivo e método para dispersar óleo em água
FR3036624B1 (fr) Dispositif de gonflage de multiples enveloppes
HK1247603A1 (zh) 具備環流式氣泡產生噴嘴的液體供給裝置
CO2017001477A2 (es) Prueba grafotécnica con obstáculo para visar firmas a simple vista
FR3011281B1 (fr) Dispositif de pressurisation autogene d'un reservoir
BR112016027657A2 (pt) Kit de frascos
CO2018003513A2 (es) Un modulo de sensor de alcohol, un alcoholímetro y un sensor
BR112017022641A2 (pt) arranjo de bomba de combustível de aeronave, sistema de abastecimento de aeronave, aeronave e tampa de entrada de inspeção para uma aeronave
BR102015024890B8 (pt) Artigo absorvente

Legal Events

Date Code Title Description
B06U Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]
B11B Dismissal acc. art. 36, par 1 of ipl - no reply within 90 days to fullfil the necessary requirements