Patent Application
20050191079
1. Field of the Invention
The invention relates to an electrophotographic image forming apparatus, a cartridge and a process cartridge.
The electrophotographic image forming apparatus is an apparatus for forming an image on a recording medium (such as recording paper or an OHP sheet) by the use of an electrophotographic image forming process. It includes, for example, an electrophotographic copying machine, an electrophotographic printer, etc.
The cartridge refers to a charging unit, a developing unit and a process cartridge. The charging unit has a charging member for charging an electrophotographic photosensitive member, and is detachably mountable to an electrophotographic image forming apparatus main body. Also, the developing unit has a developing member for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and is detachably mountable to the electrophotographic image forming apparatus main body. Also, the process cartridge refers to at least one of the charging member and the developing member as process means and the electrophotographic photosensitive member integrally made into a cartridge which is made detachably mountable to the electrophotographic image forming apparatus main body.
2. Related Background Art
In an electrophotographic image forming apparatus of a process cartridge type, the mounting and dismounting of the process cartridge with respect to an electrophotographic image forming apparatus main body (hereinafter referred to as the “apparatus main body”) can be effected by a user himself without resort to a serviceman. So, the operability of the image forming apparatus could be markedly improved.
In such an electrophotographic image forming apparatus, it is necessary to apply a voltage to a charging member for charging an electrophotographic photosensitive member the process cartridge has, or a developing member or the like for developing an electrostatic latent image formed on the electrophotographic photosensitive member. Also, the giving and receiving of a voltage and a detection signal (output voltage) to and from developer amount detecting means of an electrostatic capacity detecting type or the like the process cartridge has are sometimes effected.
So, when the process cartridge has been mounted to the apparatus main body, it is necessary to effect electrical connection between the process cartridge and the apparatus main body. Therefore, a cartridge electrical contact has heretofore been provided on the frame member of the process cartridge. On the other hand, in the apparatus main body, there is provided a main body electrical contact to be electrically connected to the cartridge electrical contact. Thereby, when the process cartridge has been mounted to the apparatus main body, the cartridge electrical contact and the main body electrical contact are connected together. Thereby, a voltage and a signal are given and received between the apparatus main body and the process cartridge.
Now, during the interchange of the process cartridge or when the jam of a recording medium occurs, an operator performs the operation of dismounting and mounting the process cartridge.
When the process cartridge is detached from the apparatus main body, the main body electrical contact member becomes exposed in the apparatus main body. So, the operator may inadvertently touch the contact member. Thereupon, the fat or the like of his hand may adhere to the contact member, and this has led to the possibility that the reliability of electrical connection is spoiled.
In order to protect such a contact member, there has been proposed a construction in which a protective plate provided in the apparatus main body is moved in operative association with the operation of dismounting and mounting the process cartridge to thereby open and close a contact window (Japanese Patent Application Laid-Open No. 7-77921).
The present invention is further development of the aforedescribed conventional art.
It is an object of the present invention to provide an electrophotographic image forming apparatus and a cartridge or a process cartridge improved in the reliability of electrical connection between a cartridge electrical contact and a main body electrical contact.
It is another object of the present invention to provide an electrophotographic image forming apparatus in which it is difficult for stains to adhere to a main body electrical contact.
It is still another object of the present invention to provide an electrophotographic image forming apparatus and a cartridge or a process cartridge in which an electrical contact cover member is moved relative to a main body electrical contact member in operative with the operation of mounting a cartridge to an electrophotographic image forming apparatus main body, whereby a cartridge electrical contact and the main body electrical contact are electrically connected together.
These and other objects, features and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
An electrophotographic image forming apparatus and a process cartridge according to an embodiment of the present invention will hereinafter be described in greater detail with reference to the drawings.
{1. General Constructions and Operation of the Electrophotographic Image Forming Apparatus}
Reference is first had to
Description will hereinafter be made with a laser beam printer taken as an example of the image forming apparatus 100. The image forming apparatus 100 forms an image on a recording medium (e.g. recording paper, an OHP sheet or cloth) by the use of an electrophotographic image forming process in accordance with an image information signal transmitted thereto from a personal computer (or a scanner apparatus or the like) connected to an apparatus main body A for communication therewith.
The image forming apparatus 100 has a drum-shaped electrophotographic photosensitive member (hereinafter referred to as the “photosensitive drum”) 107. Image forming will hereinafter be described. The surface of the photosensitive drum 107 being rotated is first uniformly charged by a charging roller 108 as a charging member. Then, a laser beam conforming to image information is applied from optical means 101 having a laser diode, a polygon mirror, a lens and a reflecting mirror (all being not shown) to the photosensitive drum 107. Thereby, an electrostatic latent image conforming to the image information is formed on the photosensitive drum 107. A developer is then supplied to this electrostatic latent image by a developing roller 110 as a developing member. As a result, a developer image is formed on the photosensitive drum 107.
On the other hand, in synchronism with the forming of the developer image on the photosensitive drum 107, a recording medium 102 set in a cassette 103a is conveyed by a feed roller 103b and pairs of conveying rollers 103c, 103d and 103e. The recording medium 102 is further fed to a transferring position in a conveying direction indicated by arrow Z along an upper transfer guide 103i and a lower transfer guide 103j. The upper transfer guide 103i and the lower transfer guide 103j together constitute a conveying guide for guiding the conveying direction of the recording medium 102. At the transferring position, a transfer roller 104 as transferring means is disposed in opposed relationship with the photosensitive drum 107. A voltage is applied to this transfer roller 104, whereby the developer image on the photosensitive drum 107 is transferred to the recording medium 102.
The recording medium 102 to which the developer image has been transferred is conveyed to fixing means 105 through an ante-fixing guide 103f. The fixing means 105 is provided with a drive roller 105c and a fixing roller 105b containing a heater 105a therein. It applies heat and pressure to the passing recording medium 102 to thereby fix the developer image on the recording medium 102. Thereafter, the recording medium 102 is conveyed by pairs of rollers 103g and 103h, and is discharged onto a tray 106.
The feed roller 103b, the pairs of rollers 103c, 103d, 103e, the upper transfer guide 103i, the lower transfer guide 103j, the ante-fixing guide 103f, the pairs of rollers 103g, 103h, etc. together constitute conveying means 103 for conveying the recording medium 102.
{2. Cartridge}
Reference is now had also to
The cartridge B has the photosensitive drum 107. When as shown in
The charging roller 108 as a charging member is provided in opposed relationship with the outer peripheral surface of the photosensitive drum 107. The charging roller 108 has a voltage (charging bias) applied thereto from the apparatus main body A. The charging roller 108 then charges the photosensitive drum 107. The charging roller 108 is provided in contact with the photosensitive drum 107. The charging roller 108 is driven to rotate by the photosensitive drum 107. When the cartridge B has been mounted on the apparatus main body A, the charging roller 108 receives a voltage from the apparatus main body A through a charging output electrical contact 144a (see
Also, the cartridge B has the developing roller 110 as a developing member. The developing roller 110 supplies a developer “t” to the developing area of the photosensitive drum 107. The developing roller 110 develops the electrostatic latent image formed on the photosensitive drum 107, by the use of this developer “t”. The developing roller 110 contains a magnet roller (stationary magnet) 111 therein.
A developing blade 112 as a developer amount regulating member is provided in abutting relationship with the peripheral surface of the developing roller 110. The developing blade 112 regulates the amount of the developer “t” adhering to the peripheral surface of the developing roller 110. Further, the developing blade 112 imparts triboelectric charges to the developer “t”.
The developer “t” contained in a developer container 114 is carried into a developing chamber 113a by the rotation of agitating members 115 and 116. On the other hand, the developing roller 110 to which a voltage (developing bias) has been applied is being rotated. A layer of developer “t” to which the triboelectric charges have been imparted by the developing blade 112 is formed on the surface of the developing roller 110. The developer “t” formed on the surface of the developing roller 110 moves to the photosensitive drum 107 in conformity with the latent image. Thereby, the latent image is developed.
When the cartridge B has been mounted on the apparatus main body A, the developing roller 110 receives a voltage from the apparatus main body A through a developing output electrical contact 161a (see
The cartridge B according to the present embodiment is provided with a first detecting electrode 190 and a second detecting electrode 191 as developer amount detecting means capable of detecting the remaining amount of the developer “t” in accordance with the consumption thereof. The first detecting electrode 190 and the second detecting electrode 191 are provided at locations contacting with the developer. Further, the first detecting electrode 190 and the second detecting electrode 191 are disposed at such locations that the areas of contact thereof with the developer fluctuate as the developer “t” is decreased. According to the present embodiment, the first detecting electrode 190 and the second detecting electrode 191 are disposed along the lengthwise direction of the developing roller 110 so as to be opposed to the developing roller 110. In this state, a voltage is applied to one of the first detecting electrode 190 and the second detecting electrode 191. By doing so, capacitance is induced between the two electrodes 190 and 191. The output voltage at this time is measured by the apparatus main body A. Thereby the developer amount is detected.
The cartridge B is provided with a first cartridge remaining amount detecting contact 188a and a second cartridge remaining amount detecting contact 189a as cartridge electrical contacts.
In the present embodiment, the first cartridge remaining amount detecting contact 188a is connected to the first detecting electrode 190. Also, the second cartridge remaining amount detecting contact 189a is connected to the second detecting electrode 191.
The developer image formed on the photosensitive drum 107 is transferred to the recording medium 102 by the transfer roller 104. An elastic cleaning blade 117a as a cleaning member is disposed in opposed relationship with the outer peripheral surface of the photosensitive drum 107. The tip end of the cleaning blade 117a abuts against the photosensitive drum 107. After the developer image has been transferred to the recording medium 102, the cleaning blade 117a removes any developer “t” residual on the photosensitive drum 107. The developer “t” removed from the surface of the photosensitive drum 107 by the cleaning blade 117a is contained in a removed developer reservoir 117b.
The cartridge B is constructed by a developing unit 119 and a drum unit 120 being made integral with each other. The developing unit 119 has a developing frame member 113 which is a portion of a cartridge frame member B1. The developing unit 119 further has the developing roller 110, the developing blade 112, the developing chamber 113a, the developer container 114, the agitating members 115, 116, the first detecting electrode 190, the second detecting electrode 191, etc. Also, the drum unit 120 has a drum frame member 118 which is a portion of the cartridge frame member B1. The drum unit 120 further has the photosensitive drum 107, the cleaning blade 117a, the removed developer reservoir 117b and the charging roller 108.
Also, the developing unit 119 and the drum unit 120 are pivotally coupled together by a pin (not shown). The developing roller 110 is pressed against the photosensitive drum 107 by a resilient member (not shown) provided between the two units 119 and 120.
{3. Mounting and Dismounting of the Cartridge}
Description will now be made of the mounting and dismounting of the cartridge B with respect to the apparatus main body A.
As shown in
As shown in
As shown in
In the present embodiment, the first right main body guide 130R1, the second right main body guide 130R2, the first left main body guide 130L1 and the second left main body guide 130L2 are formed on an inner side plate (frame member) 132 of a predetermined thickness. The inner side plate 132 is fixed to the inner side of the side plate 145 of the apparatus main body A. The inner side plate 132 is cut away into a predetermined shape. An upper end surface forming a level difference relative to the side plate 145 provides the first right main body guide 130R1, the second right main body guide 130R2, the first left main body guide 130L1 and the second left main body guide 130L2. A groove 131L as a main body guide for guiding the cartridge B into the apparatus main body A is formed between the first left main body guide 130L1 and the lower end surface 132a of the inner side plate 132 opposed substantially parallel thereto. This groove 131L plays the role as the main body guide for guiding the cartridge B into the apparatus main body A. Likewise, a groove 130R is formed between the first right main body guide 130R1 and the lower end surface 132a of the inner side plate B opposed substantially parallel thereto. This groove 130R also plays the role as the main body guide.
The first right cartridge guide 140R1 then fits to the positioning portion 130R1a of the first right main body guide 130R1. Further, the second right cartridge guide 140R2 abuts against the positioning portion 130R2a of the second right main body guide 130R2. Also, the first left cartridge guide 140L1 fits to the first positioning portion 130L1a of the first left main body guide 130L1. Further, the second left cartridge guide 140L2 abuts against the positioning portion 130L2a of the second left main body guide 130L2. Thus, the cartridge B is positioned on the apparatus main body A. As described above, the cartridge B is detachably mounted on the cartridge mounting portion 130a by the mounting means 130. The cartridge B becomes capable of performing an image forming operation by being mounted on the cartridge mounting portion 130.
The cartridge mounting portion 130a is a space occupied by the cartridge B positioned relative to the apparatus main body A by the cartridge mounting means 130. Also, the route along which the space occupied by the cartridge B moves to the cartridge mounting portion 130a during the mounting of the cartridge B is the entry route of the cartridge B.
Here, a coupling 134 as a driving force transmitting portion for transmitting drive to the cartridge B is provided in the apparatus main body A. When the cartridge B is to be mounted, the coupling 134 provided in the apparatus main body A is retracted. Accordingly, the coupling 134 does not hinder the mounting of the cartridge B. Also, the coupling 107a (
{4. Electrical Contacts of the Apparatus Main Body and the Cartridge}
As shown in
In the present embodiment, each of the charging input electrical contact member 141 and the developing input electrical contact member 160 is comprised of a thin metal plate. On the other hand, each of the first cartridge remaining detecting contact member 188 and the second cartridge remaining amount detecting contact member 189 is comprised of a metal bar.
Further, the charging input electrical contact member 141 is provided on the left end portion 120L of the drum unit 120. Also, the charging input electrical contact member 141 is provided so as to be exposed from below and the side of the drum frame member 118 with the cartridge B mounted on the apparatus main body A. The exposed side portion which is apportion of this charging input electrical contact member 141 is a charging input contact 141a as a cartridge electrical contact. The charging input contact 141a is provided more inside the cartridge B than a drum frame member side 118a.
Also, the developing input electrical contact member 160, the first cartridge remaining amount detecting contact member 188 and the second cartridge remaining amount detecting contact member 189 are provided on the left end portion 190L of a developing unit 190. Further, the developing input electrical contact member 160, the first cartridge remaining amount detecting contact member 188 and the second cartridge remaining amount detecting contact member 189 are provided so as to be exposed from below the developing frame member 113 with the cartridge B mounted on the apparatus main body A.
The developing input electrical contact member 160 is worked by bending a thin metal plate at an acute angle. A developing input electrical contact 160a as a cartridge electrical contact is constructed on the outer tip end of the bent portion thereof. Also, a first cartridge remaining amount detecting contact 188a and a second cartridge remaining amount detecting contact 189a are exposed below as respective portions of the first cartridge remaining amount detecting contact member 188 and the second cartridge remaining amount detecting contact member 189. The first cartridge remaining amount detecting contact 188a and the second cartridge remaining amount detecting contact 189a are provided along the lengthwise direction of the cartridge B (the axial direction of the photosensitive drum 107). The developing input electrical contact 160a, the first cartridge remaining amount detecting contact 188a and the second cartridge remaining amount detecting contact 189a are provided more inside the cartridge B than a developing unit side 119a.
The charging input electrical contact 141a, the developing input electrical contact 160a, the first cartridge remaining amount detecting contact 188a and the second cartridge remaining amount detecting contact 189a are provided in the named order from downstream to upstream with respect to the direction X in which the cartridge B is mounted. Also, the first cartridge remaining amount detecting contact 188a, the second cartridge reaming amount detecting contact 189a and the developing input electrical contact 160a are provided in the named order from the developing unit side 119a to the inside of the cartridge B.
The charging input electrical contact 141a, the developing input electrical contact 160a, the first cartridge remaining amount detecting contact 188a and the second cartridge remaining amount detecting contact 189a are electrically connected to the charging roller 108, the developing roller 110, the first detecting electrode 190 and the second detecting electrode 191, respectively, in the interior of the cartridge B.
On the other hand, as shown in
When the cartridge B is mounted, the first main body remaining amount detecting contact member 163 and the second main body remaining amount detecting contact member 164 contact with and are electrically connected to the cartridge remaining amount detecting contacts 188a and 189a, respectively. Thereby, the apparatus main body A can apply a voltage to one of the first detecting electrode 190 and the second detecting electrode 191. Also, the apparatus main body A can receive a developer amount detection voltage from the other of the first detecting electrode 190 and the second detecting electrode 191.
A charging output electrical contact 144a, a developing output electrical contact 161a, a first main body remaining amount detecting contact 163a and a second main body remaining amount detecting contact 164a as main body electrical contacts are provided as respective portions of the main body electrical contact members 144, 161, 163 and 164. These main body electrical contacts 144a, 161a, 163a and 164a are provided in the named order from downstream to upstream with respect to the direction X in which the cartridge B is mounted. Also, the first main body remaining amount detecting contact 163a, the second main body remaining amount detecting contact 164a and the developing output electrical contact 161a are provided in the named order from the inner side plate 132 to the inside of the cartridge mounting portion 130a.
When the cartridge B is inserted in the direction of arrow X along the aforedescribed cartridge mounting means 130 and is mounted on the apparatus main body A, the main body electrical contacts 144a, 161a, 163a and 164a are electrically connected to the cartridge electrical contacts 141a, 160a, 188a and 189a, respectively. Thereby, a charging bias is applied through the charging output electrical contact 144a and the charging input electrical contact 141a. Also, a developing bias is applied through the developing output electrical contact 161a and the developing input electrical contact 160a. Also, developer remaining amount detection can be effected through the first main body remaining amount detecting contact 163a, the second main body remaining amount detecting contact 164a, the first cartridge remaining amount detecting contact 188a and the second cartridge remaining amount detecting contact 189a. Then, the process cartridge becomes capable of operating.
In the present embodiment, the developing output electrical contact 161, the first main body remaining amount detecting contact 163 and the second main body remaining amount detecting contact 164 are disposed in the cartridge mounting portion 130a while being covered with electrical contact cover members 151, 153 and 154, respectively.
In the present embodiment, description will be made of a case where the electrical contact cover members 151, 153 and 154 are provided for the developing output contact 161, the first main body remaining amount detecting contact 163 and the second main body remaining amount detecting contact 164, respectively. In the construction of the present embodiment, the developing output electrical contact 161a, the first main body remaining amount detecting contact 163a and the second main body remaining amount detecting contact 164a are on the upstream side with respect to the mounting direction of the cartridge B. On the other hand, the charging output electrical contact 144a is on the downstream side with respect to the aforementioned mounting direction. Accordingly, during jam treatment (taking out a jammed recording medium from the apparatus main body when the recording medium is jammed in the apparatus main body) or the like, the operator's hand is liable to have access to the developing output electrical contact 161a, the first main body remaining amount detecting contact 163a and the second main body remaining amount detecting contact 164a. So, the electrical contact cover members 151, 153 and 154 are provided for the developing output contact 161, the first main body remaining amount detecting contact 163 and the second main body remaining amount detecting contact 164, respectively. Of course, a similar construction can also be applied to the charging output electrical contact member 144.
Description will further be made with reference to
The cartridge B is inserted in the direction of arrow X along the aforedescribed cartridge mounting means 130 and is mounted on the apparatus main body A. Then, the cartridge electrical contact members 166, 188 and 189 contact with the main body electrical contact members 161, 163 and 164, respectively, with moderate spring pressure.
{5. Construction of the Electrical Contact Cover Members}
Reference is now had to
In the present embodiment, the developing output electrical contact member 161, the first main body remaining amount detecting contact member 163 and the second main body remaining amount detecting contact member 164 are of the same construction. Also, the contact covers 151, 153 and 154 attached to these respective electrical contacts are substantially of the same construction. Accordingly, description will hereinafter be made of the developing output electrical contact member (hereinafter, in the present embodiment, simply referred to as the “main body contact member”) 161 as a representative example, and the contact cover 151 attached thereto.
In the present embodiment, the main body contact member 161 is formed by a torsion coil spring which is a resilient member. The main body contact member 161 is mounted on a shaft 132b provided in the inner side plate (frame member) 132 of the apparatus main body A. One arm portion of the main body contact member 161 forms a U-shaped portion 161A bent into a substantially U-shape. The other arm portion (base) 161b of the main body contact member (torsion coil spring) 161 is connected to an electric circuit (not shown) in the interior of the apparatus main body A.
The developing output electrical contact (hereinafter, in the present embodiment, simply referred to as the “main body contact”) 161a as a main body electrical contact is provided on the straight portion 161B of the base 161b side of the U-shaped portion 161A. By the above-described construction, the main body contact 161a as a main body electrical contact is made movable relative to the apparatus main body A.
The main body contact 161a contacts with and is electrically connected to the developing input electrical contact (hereinafter, in the present embodiment, simply referred to as the “cartridge contact”) 160a provided in the cartridge B, with the cartridge B mounted on the apparatus main body A. The cartridge contact 160a is the contact of the developing input electrical contact member (hereinafter, in the present embodiment, simply referred to as the “cartridge contact member”) 160.
The contact cover 151 is attached to the main body contact member 161 to cover the U-shaped portion 161A of the main body contact member 161. In the present embodiment, the contact cover 151 covers substantially the whole of the U-shaped portion 161A.
That is, as shown in
In the present embodiment, a movable portion 161C is constructed on the end 161g side of the U-shaped portion 161A of the main body contact 161. On the movable portion 161C, there is constructed an inclined portion 161d widely spaced apart from the straight portion 161B toward the end 161g. That portion of this inclined portion 161d which is most widely spaced apart from the straight portion 161B is a top 161e. A restraining portion 161f is provided from the top 161e toward the straight portion 161B. The restraining portion 161f is substantially perpendicular from the top 161e to the straight portion 161B. The end 161g is substantially parallel to the straight portion 161B further from this restraining portion 161f.
On the other hand, as shown in
A bumping portion 151g for bumping against the tip end 161h of the main body contact member 161 is provided inside the contact cover 151. Here, in the direction S of attachment to the main body contact member 161, the width W1 from the bumping portion 151g to the edge portion 151f of the opening portion 151c is greater than the width W2 from the tip end 161h to the restraining portion 161f in the same direction. Accordingly, with the contact cover 151 attached to the main body contact member 161f, the contact cover 151 is movable relative to the main body contact member 161. Also, in this state, the restraining portion 161f abuts against the edge portion 151f. Therefore, it never happens that the contact cover 151 inadvertently slip out from the main body contact member 161.
Also, a regulating portion 151d is provided inside the contact cover 151. The regulating portion 151d regulates the position of the straight portion 161B of the U-shaped portion 161A. This regulating portion 151d makes the straight portion 161B parallel to the inner side of the contact cover 151. Then, a portion of the straight portion 161B is exposed to the cut-away portion 151a. When the contact cover 151 is to be attached to the main body contact member, the tip end 161h of the U-shaped portion 161A clears this regulating portion 151d.
Further, a side stop 151e is provided so that the contact cover 151 may not break away sideways. The side stop 151e is provided substantially in parallelism to a plane formed by the U-shaped portion 161A of the main body contact member 161. This side stop 151e holds the main body contact member 161 relative to the inner side of the contact cover 151.
In the present embodiment, the contact cover 151 is provided with a cut-away portion (opening portion) 151a. The lower end portion of this cut-away portion 151a which communicates with the interior of the contact cover 151 is an exposed portion 151a1. This exposed portion 151a1 exposes the main body contact 161a to the outside of the contact cover 151. Thereby, the exposed portion 151a1 permits the connection between the cartridge contact 160a and the main body contact 161a. The cut-away portion 151a is formed to a size at which the cartridge contact 160a and the main body contact 161a can contact with each other. That is, the cut-away portion 151a corresponds to the size of the cartridge contact member 160. When the cartridge B is mounted on the apparatus main body A, at least a portion of the cartridge contact member 160 enters this cut-away portion 151a. Then, in the exposed portion 151a1, the cartridge contact 160a contacts with the contact portion (main body contact) 161a of the main body contact member 161.
Also, the contact cover 151 is provided with a first guide portion 151b1 and a second guide portion 151b2 as receiving portions abutting against an abutting portion (in the present embodiment, the cartridge contact member 160) the cartridge B has. In the present embodiment, the first guide portion 151b1 and the second guide portion 151b2 are provided on the inner side wall of the cut-away portion 151a. In other words, the first guide portion 151b1 and the second guide portion 151b2 are provided on the end portion of the exposed portion 151a1. In operative association with the mounting operation of mounting the cartridge B on the apparatus main body A, the abutting portion of the cartridge B first abuts against the first guide portion 151b1 and the second guide portion 151b2. Next, the first guide portion 151b1 and the second guide portion 151b2 are pushed by the abutting portion of the cartridge B, whereby the contact cover 151 is moved relative to the main body contact member 161. Accordingly, the exposed portion 151a1 is also moved relative to the main body contact member 161. Then, in the exposed portion 151a1, the cartridge contact 160a and the main body contact 161a are electrically connected together. That is, in operative association with the connection of the cartridge B to the apparatus main body A, the cartridge contact 160a and the main body contact 161a are electrically connected together.
Further describing, with cartridge B mounted on the apparatus main body A, the cut-away portion 151a is provided so as to face in a direction in which the cartridge B comes in during the mounting of the cartridge B. Further, the cut-away portion 151a is provided so that in the exposed portion 151a1, the straight portion 161B of the main body contact member 161 may be exposed. The cut-away portion 151a is preferably smaller than the tip end of a finger. Further, the cut-away portion 151a is of a shape larger than that portion of the cartridge contact member 160 which comes thereinto.
The first guide portion 151b1 and the second guide portion 151b2 are the inner sides of the cut-away portion 151a. Also, the first guide portion 151b1 and the second guide portion 151b2 are opposed to each other along the direction S of movement of the contact cover 151. Also, the spacing between the first guide portion 151b1 and the second guide portion 151b2 in the direction S of movement becomes narrower toward the exposed portion 151a1. That is, in the present embodiment, the first guide portion 151b1 and the second guide portion 151b2, when seen from the mounting direction X of the cartridge B, are constituted by the inner sides of an opening portion continuous to the exposed portion 151a1 (i.e., the straight portion 161B of the main body contact member 161 in the interior of the contact cover 151). Therefore, the cartridge contact 160a is smoothly directed to the main body contact 161a. Further, the width of the opening portion becomes narrower toward the exposed portion 151a1 (i.e., the straight portion 161B of the main body contact member 161 in the interior of the contact cover 151). In the present embodiment, the direction of movement of the contact cover 151 (the direction of movement of the contact cover 151 relative to the apparatus main body A) is substantially the same direction as the mounting direction X of the cartridge B.
Although not restricted to this, the width of the upper end of the cut-away portion 151a in the direction T of movement of the contact cover 151 relative to the main body electrical contact member 161 (the maximum spacing W3 between the first guide portion 151b1 and the second guide portion 151b2) is 4 to 8 mm. Also, the width of the lower end portion of the cut-away portion in the same direction (the width W4 of the exposed portion 151a1) is 2 to 4 mm. Further, the height H1 from the upper end to the lower end portion of the cut-away portion 151a (the exposed portion 151a1) is 2 to 3 mm.
In the present embodiment, as shown in
Accordingly, even when the operator had access to each contact member of the apparatus main body A during jam treatment or the mounting and dismounting of the cartridge, it is difficult for the operator's fingers to touch the main body contact 161a of the main body contact member 161. Further, the size of the cut-away portion 151a is smaller than the tip ends of the fingers and larger than the cartridge contact 160a. Therefore, it becomes substantially impossible for the operator's fingers to touch the contact portion (main body contact) 161a of the cartridge contact member 160.
Thus, it is difficult for a foreign substance (for example, the developer or grease adhering to the operator's hand, or man's sweat or fat) to adhere to the electrical contacts of the apparatus main body A. Therefore, it is difficult for the faulty electrical conduction of the electrical contacts to occur. As a result, it is possible to improve the reliability of the electrical connection between the electrical contacts of the cartridge B and the electrical contacts of the apparatus main body A. For example, it is possible to make it difficult for the injury of the electrical contacts caused by the operator's hand touching them to occur.
Reference is now had also to FIGS. 12 to 14 to further describe the movement of the contact cover 151 during the mounting of the cartridge B onto the apparatus main body A.
During the mounting of the cartridge B onto the apparatus main body A, the cartridge B is moved in the direction of arrow X along the aforedescribed cartridge mounting means 130 by the operator's mounting operation (
As indicated by dots-and-dash line in
Then, the cartridge B is further inserted. Thereby, as indicated by dot-and-dash line in
By the cartridge B being further inserted, the mounting guide members 140R1, 140R2, 140L1 and 140L2 of the cartridge B are positioned relative to the cartridge mounting means 130. During the time until the positioning, the cartridge contact member 160 further moves the contact cover 151 as indicated by arrow T2. As indicated by solid line in
Also, in the present embodiment, the main body contact member 161 is formed by a torsion coil spring. In the present embodiment, this torsion coil spring is designed to flex in the mounting direction X of the cartridge B. Therefore, in a state in which the cartridge B is mounted on the apparatus main body A, the spring is brought down in the direction of arrow U (
Also, when the cartridge B is to be taken out of the apparatus main body A, an operation opposite to what has been described above is performed.
In the foregoing, when the cartridge B is to be mounted on the apparatus main body A, the cartridge contact member 160 abuts against the first guide portion 151b1. It has been described that at that time, the contact cover 151 moves in the forward direction (T1, T2) with respect to the mounting direction X of the cartridge B. However, this is not restrictive. In some cases, conversely the cartridge contact member 160 abuts against the second guide portion 151b2 in conformity with the position or the like of the contact cover 151 relative to the main body contact member 161 when the cartridge B is mounted. Further, there is also a case where the contact cover 151 moves in a direction opposite to the mounting direction X of the cartridge B. In the present embodiment, in a state in which the cartridge B is not mounted on the apparatus main body A, the contact cover 151 is lowered downwardly by gravity. Further, the tip end 151h of the contact member abuts against the bumping portion 151g. When the cartridge B is then mounted on the apparatus main body A, the contact cover 151 is moved in the forward direction with respect to the mounting direction X of the cartridge B. Also, as previously described, the contact cover 151 is movable in the direction of arrow T relative to the main body contact member 161. Further, the main body contact 161a is movable in the direction of arrow V relative to the apparatus main body A. The direction of arrow V is substantially perpendicular to the direction of arrow T. Therefore, the exposed portion 151a1 is movable in the direction of arrow V and the direction of arrow T perpendicular thereto. Accordingly, the degree of freedom of the movement of the exposed portion 151a1 can be secured by an inexpensive construction. Consequently, the reliability of the electrical connection between the main body contact 161a and the cartridge contact 160a can be improved.
With regard also to the other main body electrical contacts, i.e., the first main body remaining amount detecting contact member 163 and the second main body remaining amount detecting contact member 164, the constructions and operations of the contact covers 153, 154 and the main body contact members 163, 164 are similar to those of the developing output contact member 151 and the contact cover 151 thereof.
Also, in the present invention, description has been made of a case where the contact covers 151, 153 and 154 are provided particularly for the developing output contact 161, the first main body remaining amount detecting contact 163 and the second main body remaining amount detecting contact 164, respectively. Of course, however, a similar construction can also be applied to the charging output electrical contact member 144 in conformity with the mode of disposition or the like of the charging output electrical contact member 144, whereby the reliability of the electrical connection between the electrical contacts of the apparatus main body A and the electrical contacts of the cartridge B can be further improved.
{6. Circuit Board EC (Electric Circuit E)}
Here, a charging bias circuit E1 generates a negative DC voltage and an AC voltage. A voltage comprising the above-mentioned voltages superimposed one upon the other is then applied to the charging roller 108. The charging roller 108 receives this voltage and charges the photosensitive drum 107. The charging bias circuit E1 applies a negative DC voltage also to the fixing roller 105b through the drive roller 105c.
Also, a developing bias circuit E2 generates a negative DC voltage and an AC voltage. A voltage comprising the aforementioned voltages superimposed one upon the other is then applied to the developing roller 110 and the second detecting electrode 191. The developing roller 110 receives this voltage and develops the electrostatic latent image by a developer.
Also, a transferring bias circuit E3 generates a positive or negative DC voltage. Then, it applies the positive or negative DC voltage to the transfer roller 104.
Further, the first detecting electrode 190 is connected to the detecting circuit of a developer remaining amount detecting circuit E4, and an output voltage (developer amount detection voltage) when a voltage has been applied to the second detecting electrode 191 and the developing roller 110 is inputted thereto. Also, a reference voltage generating circuit generates a reference voltage in detecting the remaining amount of the developer, by the use of a current applied from the developing bias circuit E2. Then, the detecting circuit outputs the difference between the reference voltage and the developer amount detection voltage as the detected value of the remaining amount of the developer to a CPU. The information of the thus detected remaining amount of the developer is reported to the use by a display portion (not shown) or the like provided on the image forming apparatus main body A.
As described above, a voltage from a voltage source S is supplied to the charging roller 108 through the charging bias circuit E1. Also, the voltage from the voltage source S is supplied to the fixing roller 105b and the drive roller 105c through the charging bias circuit E1. Further, the voltage from the voltage source S is supplied to the developing roller 110 and the second detecting electrode 191 through the developing bias circuit E2. Also, the voltage from the voltage source S is supplied to the transfer roller 104 through the transfer charging bias circuit E3.
These circuits E1, E2 and E3 have their ON and OFF controlled by instructions from a CPC 200 provided on a circuit board EC. The circuit board EC mounted on the apparatus main body A will now be described with reference to
Also, the voltage source S is connected to the circuit board EC, i.e., the electric circuit E. The electric circuit E is comprised of the charging bias circuit E1, the developing bias circuit E2, the transfer charging bias circuit E3 and the developer remaining amount detecting circuit E4.
The charging bias circuit E1 generates a negative DC voltage and an AC voltage. It applies to the charging roller 108 a voltage comprising the aforementioned voltages superimposed one upon the other. The charging roller 108 receives this voltage and charges the photosensitive drum 107. The charging bias circuit E1 also applies the negative DC voltage to the fixing roller 105b through the drive roller 105c.
Also, the developing bias circuit E2 generates a negative DC voltage and an AC voltage. It applies to the developing roller 110 and the second detecting electrode a voltage comprising the aforementioned voltages superimposed one upon the other. The developing roller 110 receives this voltage and develops the electrostatic latent image by the developer.
Also, the transferring bias circuit E3 generates a positive or negative DC voltage. It appears the positive or negative DC voltage to the transfer roller 104. Further, the first detecting electrode 190 is connected to the detecting circuit of the developer remaining amount detecting circuit E4, and an output voltage (developer amount detection voltage) when a voltage has been applied to the second detecting electrode 191 and the developing roller 110 is inputted. Also, the reference voltage generating circuit generates a reference voltage in detecting the remaining amount of the developer, by the use of a current applied from the developing bias circuit E2. Then, the detecting circuit outputs the difference between the reference voltage and the developer amount detection voltage as the detected value of the remaining amount of the developer to the CPU. The thus detected information of the remaining amount of the developer is reported to the use by a display portion (not shown) or the like provided in the image forming apparatus main body A.
As described above, the voltage from the voltage source S is supplied to the charging roller 108 through the charging bias circuit E1. Also, the voltage from the voltage source S is supplied to the fixing roller 105b and the drive roller 105c through the charging bias circuit E1. Further, the voltage from the voltage source S is supplied to the developing roller 110 and the second detecting electrode 191 through the developing bias circuit E2. Also, the voltage from the voltage source S is supplied to the transfer roller 104 through the transfer charging bias circuit E3.
These circuits have their ON and OFF controlled by the instructions from the CPU 200 provided on the circuit board EC.
Thus, in the present embodiment, the following effects can be achieved.
(1) The contact covers 151, 153 and 154 are mounted for movement relative to the main body contact members 161, 163 and 164 provided with the main body contacts 161a, 163a and 164a electrically connected to the cartridge contacts 160a, 188a and 189a the cartridge has, and these contact covers 151, 153 and 154 are designed to move in operative association with the mounting operation of the cartridge B.
Thus, even when a foreign substance has come into the apparatus main body A such as when with the cartridge B taken out of the apparatus main body A, the operator inserts his hand to perform the mounting of the cartridge B, maintenance or jam treatment or the like, the apparatus main body contact members 161, 163 and 164 are protected by the contact covers and therefore, the operator cannot easily touch the main body contact members 161, 163 and 164 are protected by the contact covers and therefore, the operator cannot easily touch the main body contacts 161a, 163a and 164a. Therefore, it can be suppressed for a foreign substance (such as the developer or grease adhering to the operator's hand, or man's sweat or fat) to adhere to the electrical contacts of the apparatus main body A to thereby cause faulty conduction.
When the cartridge B is to be mounted on the apparatus main body A, the contact covers 151, 153 and 154 move in operative association with the mounting operation of the cartridge B. Thereby, the main body contacts 161a, 163a, 164a and the cartridge contacts 160a, 188a, 189a are electrically connected together. Consequently, the operator can very simply connect the main body contacts 161a, 163a, 164a and the cartridge contacts 160a, 188a, 189a together without performing any special operation.
Accordingly, the reliability of the electrical connection between the electrical contacts provided in the apparatus main body A and the electrical contacts provided in the cartridge B can be improved.
(2) The contact covers 151, 153 and 154 are proved with the cut-away portion 151a capable of effecting the condition of the contacts. Therefore, as compared with a shape in which the contact portion 151a is completely covered, the amounts of movement of the contact covers 151, 153 and 154 can be made small. Accordingly, the space occupied by the contact covers 151, 153 and 154 can be minimized. As the result, the image forming apparatus 100 can be made compact.
(3) Also, the cartridge contact members 160, 188 and 189 are made to abut against the guide portions 151b1 and 151b2 of the contact cover 151 as cartridge abutting portions. Thereby, the contact cover 151 is moved. Accordingly, it is possible to move the contact covers 151, 153 and 153 without adding any special part for the movement of the contact covers 151, 153 and 154. Also, the cartridge contact members 160, 188 and 189 fit into the cut-away portion 151a to thereby effect the positioning of the contact covers 151, 153 and 154. Thereby, it is possible to align the contact covers with the contacts of the cartridge B highly accurately without adding any special part for the positioning of the contact covers 151, 153 and 154. Accordingly, a contact protecting mechanism of high quality can be realized at a low cost.
Further, the inner side of the cut-away portion 151a (an opening portion continuous to the exposed portion 151a) provided on the contact covers 151, 153 and 154 are made into guide portions 151b1 and 151b2 (receiving portions). Thereby, in the operation of mounting the cartridge B on the apparatus main body A, the movement of the electrical contact cover members 151, 153 and 154, the connection of the electrical contacts and the positioning of the contact covers 151, 153 and 154 are effected in a series. Therefore, the mechanism is simple and high in reliability.
(4) The direction of movement (directions T1 and T2) of the contact cover relative to the apparatus main body A is substantially the same direction as the mounting direction (X direction) of the cartridge B. Therefore, it is possible to cope with even a case where the positions of the cartridge contact members 160, 188 and 189 fluctuate due to the unevenness of the parts of the cartridge B or the backlash thereof during the mounting. It is possible to align the contact covers 151, 153 and 154 with the electrical contacts of the cartridge B highly accurately. Accordingly, a contact protecting mechanism of high quality can be realized.
(5) In a case where the apparatus main body A has a plurality of contact members, by adopting a construction in which contact covers are individually disposed, it is possible to downsize the contact covers 151, 153 and 154 themselves, as compared with a case where a plurality of contact members are covered with a single contact cover. At the same time, the downsizing of the image forming apparatus 100 also becomes possible. Also, by adopting such a construction, the degree of freedom of the disposition of each contact member is high and it is possible to individually cope with the positional deviation of the contact members. Accordingly, the downsizing of the image forming apparatus is possible and a contact protecting mechanism of high quality can be realized.
(6) In the present embodiment, the respective electric power supplied members (the charging member, the developing member and the developer amount detecting member) are electrically connected to the respective cartridge electrical contacts (160a, 188a and 189a) in the interior of the process cartridge B as a cartridge.
(7) In the present embodiment, description has been made by the use of a process cartridge having an electrophotographic photosensitive member and process means integrally with each other. The present invention, however, is also applicable to a charging unit having a charging member for charging an electrophotographic photosensitive member, and having no electrophotographic photosensitive member. Likewise, the present invention is also applicable to a developing unit having a developing member for developing an electrostatic latent image formed on an electrophotographic photosensitive member, and having no electrophotographic photosensitive member. Here, the electrophotographic photosensitive member mountable to the apparatus main body. Or it is mounted on the apparatus main body.
According to the present invention, the reliability of the electrical connection between the electrical contacts the process cartridge has and the electrical contacts provided in the electrophotographic image forming apparatus main body can be improved.
Also, according to the present invention, it is difficult for stains to adhere to the main body electrical contacts.
Also, according to the present invention, there can be provided an electrophotographic image forming apparatus and a cartridge or a process cartridge in which in operative association with the operation of mounting the cartridge on the electrophotographic image forming apparatus main body, electrical contact cover members are moved relative to main body electrical contact members, whereby cartridge electrical contacts and main body electrical contacts are electrically connected together.
While the invention has been described with reference to the structure disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-055461 (PAT. | Feb 2004 | JP | national |
| 2004-166155 (PAT. | Jun 2004 | JP | national |
