Masahito SAEKI

Person

Nagoya-shi, JP

People

Patents Grantslast 30 patents

Information Patent Grant
Drum cartridge in which first storage medium of toner cartridge and...
- Patent number 11,789,405
- Issue date Oct 17, 2023
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus
- Patent number 11,556,089
- Issue date Jan 17, 2023
- Brother Kogyo Kabushiki Kaisha
- Hiroshi Nakano
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus with plural moving mechanisms for developin...
- Patent number 11,429,062
- Issue date Aug 30, 2022
- Brother Kogyo Kabushiki Kaisha
- Kotaro Haruta
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus including cam having compact structure capa...
- Patent number 11,372,362
- Issue date Jun 28, 2022
- Brother Kogyo Kabushiki Kaisha
- Yusuke Ikegami
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus configured to stop conveyance of sheet for...
- Patent number 11,353,806
- Issue date Jun 7, 2022
- Brother Kogyo Kabushiki Kaisha
- Shintaro Sakaguchi
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus including common drive source for driving d...
- Patent number 11,334,022
- Issue date May 17, 2022
- Brother Kogyo Kabushiki Kaisha
- Yusuke Ikegami
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus including multiple photosensitive drums and...
- Patent number 11,237,497
- Issue date Feb 1, 2022
- Brother Kogyo Kabushiki Kaisha
- Shintaro Sakaguchi
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Drum cartridge in which first storage medium of toner cartridge and...
- Patent number 11,221,585
- Issue date Jan 11, 2022
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus having cartridge and exposure device
- Patent number 11,209,744
- Issue date Dec 28, 2021
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus moving developing rollers toward and away f...
- Patent number 11,181,857
- Issue date Nov 23, 2021
- Brother Kogyo Kabushiki Kaisha
- Yusuke Ikegami
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus having moving mechanisms to move developing...
- Patent number 11,144,001
- Issue date Oct 12, 2021
- Brother Kogyo Kabushiki Kaisha
- Shintaro Sakaguchi
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus including first and second cams whose rotat...
- Patent number 11,143,985
- Issue date Oct 12, 2021
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image-forming apparatus capable of moving developing roller between...
- Patent number 11,137,718
- Issue date Oct 5, 2021
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image-forming apparatus with reduced number of motors for moving de...
- Patent number 11,106,155
- Issue date Aug 31, 2021
- Brother Kogyo Kabushiki Kaisha
- Shintaro Sakaguchi
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus including common drive source for driving d...
- Patent number 11,079,714
- Issue date Aug 3, 2021
- Brother Kogyo Kabushiki Kaisha
- Yusuke Ikegami
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus with rotation-controllable photosensitive d...
- Patent number 11,061,357
- Issue date Jul 13, 2021
- Brother Kogyo Kabushiki Kaisha
- Kazuaki Ooka
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image-forming apparatus including cam and cam follower for moving d...
- Patent number 11,009,806
- Issue date May 18, 2021
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image-forming apparatus capable of controlling separation/contact t...
- Patent number 10,990,032
- Issue date Apr 27, 2021
- Brother Kogyo Kabushiki Kaisha
- Shintaro Sakaguchi
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus and method for ensuring adequate torque of...
- Patent number 10,969,737
- Issue date Apr 6, 2021
- Brother Kogyo Kabushiki Kaisha
- Kotaro Haruta
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus
- Patent number 10,955,790
- Issue date Mar 23, 2021
- Brother Kogyo Kabushiki Kaisha
- Shintaro Sakaguchi
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus
- Patent number 10,955,791
- Issue date Mar 23, 2021
- Brother Kogyo Kabushiki Kaisha
- Hiroshi Nakano
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus with roller-drivable mechanism, roller-mova...
- Patent number 10,921,748
- Issue date Feb 16, 2021
- Brother Kogyo Kabushiki Kaisha
- Kotaro Haruta
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus with developing cartridges having increased...
- Patent number 10,859,940
- Issue date Dec 8, 2020
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Drum cartridge in which first storage medium of toner catridge and...
- Patent number 10,712,711
- Issue date Jul 14, 2020
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus
- Patent number 10,656,591
- Issue date May 19, 2020
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus operable with a cartridge having a memory a...
- Patent number 10,429,795
- Issue date Oct 1, 2019
- Brother Kogyo Kabushiki Kaisha
- Masahito Saeki
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus with a light shielding part serving as a gu...
- Patent number 10,281,871
- Issue date May 7, 2019
- Brother Kogyo Kabushiki Kaisha
- Hideaki Yoshimune
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Grant
Image forming apparatus
- Patent number 10,274,888
- Issue date Apr 30, 2019
- Borther Kogyo Kabushiki Kaisha
- Shougo Sato
- B65 - CONVEYING PACKING STORING HANDLING THIN OR FILAMENTARY MATERIAL
Information Patent Grant
Image forming apparatus
- Patent number 10,126,698
- Issue date Nov 13, 2018
- Brother Kogyo Kabushiki Kaisha
- Shougo Sato
- B65 - CONVEYING PACKING STORING HANDLING THIN OR FILAMENTARY MATERIAL
Information Patent Grant
Image forming apparatus
- Patent number 10,095,158
- Issue date Oct 9, 2018
- Brother Kogyo Kabushiki Kaisha
- Tomoya Yamamoto
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY

Patents Applicationslast 30 patents

Information Patent Application
DRUM CARTRIDGE IN WHICH FIRST STORAGE MEDIUM OF TONER CARTRIDGE AND...
- Publication number 20230418220
- Publication date Dec 28, 2023
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
DRUM CARTRIDGE IN WHICH FIRST STORAGE MEDIUM OF TONER CARTRIDGE AND...
- Publication number 20220128946
- Publication date Apr 28, 2022
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS INCLUDING COMMON DRIVE SOURCE FOR DRIVING D...
- Publication number 20210278798
- Publication date Sep 9, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Yusuke IKEGAMI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS INCLUDING CAM HAVING COMPACT STRUCTURE CAPA...
- Publication number 20210200135
- Publication date Jul 1, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Yusuke IKEGAMI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
Image Forming Apparatus
- Publication number 20210165362
- Publication date Jun 3, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Hiroshi Nakano
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20210165365
- Publication date Jun 3, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Kotaro HARUTA
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS MOVING DEVELOPING ROLLERS TOWARD AND AWAY F...
- Publication number 20210141327
- Publication date May 13, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Yusuke IKEGAMI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
Image Forming Apparatus
- Publication number 20210116835
- Publication date Apr 22, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Shintaro SAKAGUCHI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20210080857
- Publication date Mar 18, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS INCLUDING COMMON DRIVE SOURCE FOR DRIVING D...
- Publication number 20210011423
- Publication date Jan 14, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Yusuke IKEGAMI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE-FORMING APPARATUS CAPABLE OF MOVING DEVELOPING ROLLER BETWEEN...
- Publication number 20210011427
- Publication date Jan 14, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS HAVING MOVING MECHANISMS TO MOVE DEVELOPING...
- Publication number 20210011416
- Publication date Jan 14, 2021
- BROTHER KOGYO KABUSHIKI KAISHA
- Shintaro SAKAGUCHI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS INCLUDING FIRST AND SECOND CAMS WHOSE ROTAT...
- Publication number 20200409290
- Publication date Dec 31, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE-FORMING APPARATUS WITH REDUCED NUMBER OF MOTORS FOR MOVING DE...
- Publication number 20200387081
- Publication date Dec 10, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Shintaro SAKAGUCHI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS CONFIGURED TO STOP CONVEYANCE OF SHEET FOR...
- Publication number 20200356023
- Publication date Nov 12, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Shintaro SAKAGUCHI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE-FORMING APPARATUS CAPABLE OF CONTROLLING SEPARATION/CONTACT T...
- Publication number 20200333727
- Publication date Oct 22, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Shintaro SAKAGUCHI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20200310281
- Publication date Oct 1, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Kotaro HARUTA
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE-FORMING APPARATUS INCLUDING CAM AND CAM FOLLOWER FOR MOVING D...
- Publication number 20200301335
- Publication date Sep 24, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20200301350
- Publication date Sep 24, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Shintaro SAKAGUCHI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20200301351
- Publication date Sep 24, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Kazuaki OOKA
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
Image Forming Apparatus and Method for Ensuring Adequate Torque of...
- Publication number 20200301358
- Publication date Sep 24, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Kotaro HARUTA
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20200292959
- Publication date Sep 17, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
DRUM CARTRIDGE IN WHICH FIRST STORAGE MEDIUM OF TONER CARTRIDGE AND...
- Publication number 20200292987
- Publication date Sep 17, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
Image Forming Apparatus
- Publication number 20200004198
- Publication date Jan 2, 2020
- BROTHER KOGYO KABUSHIKI KAISHA
- Hiroshi Nakano
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20190302676
- Publication date Oct 3, 2019
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
DRUM CARTRIDGE AND IMAGE FORMING APPARATUS
- Publication number 20190278221
- Publication date Sep 12, 2019
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
Image Forming Apparatus
- Publication number 20190041788
- Publication date Feb 7, 2019
- BROTHER KOGYO KABUSHIKI KAISHA
- Shougo Sato
- B65 - CONVEYING PACKING STORING HANDLING THIN OR FILAMENTARY MATERIAL
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20180335752
- Publication date Nov 22, 2018
- BROTHER KOGYO KABUSHIKI KAISHA
- Masahito SAEKI
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
IMAGE FORMING APPARATUS
- Publication number 20180335750
- Publication date Nov 22, 2018
- BROTHER KOGYO KABUSHIKI KAISHA
- Hideaki YOSHIMUNE
- G03 - PHOTOGRAPHY CINEMATOGRAPHY ELECTROGRAPHY HOLOGRAPHY
Information Patent Application
Image Forming Apparatus
- Publication number 20180004145
- Publication date Jan 4, 2018
- BROTHER KOGYO KABUSHIKI KAISHA
- Shougo Sato
- B65 - CONVEYING PACKING STORING HANDLING THIN OR FILAMENTARY MATERIAL

Masahito SAEKI

Person

Patents Grantslast 30 patents

Drum cartridge in which first storage medium of toner cartridge and...

Image forming apparatus

Image forming apparatus with plural moving mechanisms for developin...

Image forming apparatus including cam having compact structure capa...

Image forming apparatus configured to stop conveyance of sheet for...

Image forming apparatus including common drive source for driving d...

Image forming apparatus including multiple photosensitive drums and...

Drum cartridge in which first storage medium of toner cartridge and...

Image forming apparatus having cartridge and exposure device

Image forming apparatus moving developing rollers toward and away f...

Image forming apparatus having moving mechanisms to move developing...

Image forming apparatus including first and second cams whose rotat...

Image-forming apparatus capable of moving developing roller between...

Image-forming apparatus with reduced number of motors for moving de...

Image forming apparatus including common drive source for driving d...

Image forming apparatus with rotation-controllable photosensitive d...

Image-forming apparatus including cam and cam follower for moving d...

Image-forming apparatus capable of controlling separation/contact t...

Image forming apparatus and method for ensuring adequate torque of...

Image forming apparatus

Image forming apparatus

Image forming apparatus with roller-drivable mechanism, roller-mova...

Image forming apparatus with developing cartridges having increased...

Drum cartridge in which first storage medium of toner catridge and...

Image forming apparatus

Image forming apparatus operable with a cartridge having a memory a...

Image forming apparatus with a light shielding part serving as a gu...

Image forming apparatus

Image forming apparatus

Image forming apparatus

Patents Applicationslast 30 patents

DRUM CARTRIDGE IN WHICH FIRST STORAGE MEDIUM OF TONER CARTRIDGE AND...

DRUM CARTRIDGE IN WHICH FIRST STORAGE MEDIUM OF TONER CARTRIDGE AND...

IMAGE FORMING APPARATUS INCLUDING COMMON DRIVE SOURCE FOR DRIVING D...

IMAGE FORMING APPARATUS INCLUDING CAM HAVING COMPACT STRUCTURE CAPA...

Image Forming Apparatus

IMAGE FORMING APPARATUS

IMAGE FORMING APPARATUS MOVING DEVELOPING ROLLERS TOWARD AND AWAY F...

Image Forming Apparatus

IMAGE FORMING APPARATUS

IMAGE FORMING APPARATUS INCLUDING COMMON DRIVE SOURCE FOR DRIVING D...

IMAGE-FORMING APPARATUS CAPABLE OF MOVING DEVELOPING ROLLER BETWEEN...

IMAGE FORMING APPARATUS HAVING MOVING MECHANISMS TO MOVE DEVELOPING...

IMAGE FORMING APPARATUS INCLUDING FIRST AND SECOND CAMS WHOSE ROTAT...

IMAGE-FORMING APPARATUS WITH REDUCED NUMBER OF MOTORS FOR MOVING DE...

IMAGE FORMING APPARATUS CONFIGURED TO STOP CONVEYANCE OF SHEET FOR...

IMAGE-FORMING APPARATUS CAPABLE OF CONTROLLING SEPARATION/CONTACT T...

IMAGE FORMING APPARATUS

IMAGE-FORMING APPARATUS INCLUDING CAM AND CAM FOLLOWER FOR MOVING D...

IMAGE FORMING APPARATUS

IMAGE FORMING APPARATUS

Image Forming Apparatus and Method for Ensuring Adequate Torque of...

IMAGE FORMING APPARATUS

DRUM CARTRIDGE IN WHICH FIRST STORAGE MEDIUM OF TONER CARTRIDGE AND...

Image Forming Apparatus

IMAGE FORMING APPARATUS

DRUM CARTRIDGE AND IMAGE FORMING APPARATUS

Image Forming Apparatus

IMAGE FORMING APPARATUS

IMAGE FORMING APPARATUS

Image Forming Apparatus