FR2597219A1 - Apparatus for forming images and processing cartridge for this apparatus - Google Patents

Abstract

The invention relates to an apparatus for forming images and to a processing cartridge intended for this apparatus. It comprises a first fixed box 19, a second box 21 capable of pivoting on the box 19 to open and close the apparatus 1 for forming images, a photosensor provided in the first box, a source of light provided in this box and intended for lighting an original document carried by a trolley 10, and means intended for transmitting the light emitted by the source, in the first assembly, to the photosensor located in the second assembly. Field of application: photocopying machines, laser printers, etc.

Description

 The present invention relates to an image forming apparatus such as a copying apparatus and a laser beam printer, more particularly an image forming apparatus in which an amount of light intended to illuminate an original to be copied is detected, and / or wherein one or more parts to be discarded after use are assembled in a cartridge which is removably mounted in a main block of the image forming apparatus. The invention also relates to such a treatment cartridge.

 It is widely used image forming machines in which consumable or disposable elements or materials are housed in a cartridge which is replaced by a new cartridge at the end of its service life, and various arrangements have been proposed for these machines.

 For example, U.S. Patents NO 4,500,195, N "4,551,000, N" 4,470,689, N 4,598,993, N "4,540,268 and N" 4,563,694 describe a training device convenient to use image processing, wherein a processing cartridge contains a photosensitive member on which an image is formed, as well as other processing means.

 In such an apparatus, a structure is advantageously adopted in which a frame forming part of the main unit or block, which receives the treatment cartridge, is articulated on the remaining part of the frame of the main block, one of the frames can be opened relative to each other to facilitate replacement of the cartridge and removal of jammed paper.

 However, in such an apparatus, the frame containing the cartridge is relatively bulky and it is therefore difficult to open, or else the opening or closing action requires great force.

There is an increasing desire to reduce the dimensions and the weight of the frame containing the cartridge.

 In cases where the treatment cartridge contains at least one photosensitive element, an image developing device on the photosensitive element and a hopper containing a developer, the developer must be kept inside the hopper without arrive at the development device so that the developer does not spread or is damaged during the storage of an unused new cartridge. To this end, the Japanese utility model application No. 60-76360 proposes using a sealing device to form a partition between the developing device and the hopper. When the developing device is used, the sealing device or element so that the developer arrives at the development device.

 However, such a process cartridge may be placed inside the main apparatus whether the sealing member is in place or removed and, therefore, the process cartridge may be inserted by mistake in the camera while the shutter member is not removed, causing the imaging device to malfunction.

 The main object of the invention is therefore an image forming apparatus in which a frame containing a processing cartridge is of small size and of light weight so that it can be easily opened or closed relative to the other frame. The invention also relates to an image forming apparatus which is not easily influenced by parasites and which can safely receive a signal of quantity of light. Another subject of the invention is an image forming apparatus and a processing cartridge designed to reliably prevent any malfunction resulting from the placement of a processing cartridge in the main unit while the processing device development is not powered by developer.

The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which
Figure 1 is a longitudinal section of an embodiment of the image forming apparatus according to the invention;
Figure 2 is a longitudinal section of the apparatus of Figure 1, the upper frame is open
Figure 3 is a top plan view of the apparatus of Figure 2
Figure 4 is a cross section showing one end of an optical fiber and a sensor;
Figure 5 is a perspective view showing the same elements as in Figure 4
Figure 6 is a cross section showing a modification of the structure of Figure 4
FIG. 7 is a perspective view of a processing cartridge usable with the image forming apparatus according to the invention, in the case where no developer is supplied to the developing device
Figure 8 is a perspective view of an image forming apparatus in which a hermetically sealed process cartridge is mounted in a frame; and
Figure 9 is a top plan view of the image forming apparatus.

 With reference to the drawings in which the same reference numerals designate the same elements in the different figures, FIG. 1 illustrates an electrophotographic copying machine by way of example of an image forming apparatus constituting an embodiment of the invention . As described below, the copy machine can be opened. Figure 1 shows the machine in its closed state, while Figure 2 shows it in its open state.

 The image formation apparatus comprises a main assembly or block 1 which comprises a first frame 19 and a second frame 21 articulated by a hinge 20 so that the second frame can rotate on the hinge 20 to open the machine.

 The second frame 21 has a slit lib allowing a photosensitive element 2 to be exposed to the light of the image coming from an original to be copied, a fluorescent lamp 11 intended to illuminate the original to be copied, a reflector 11a, a network 4 of short focal imaging elements intended to form an image of the original on the photosensitive element 2, a bundle 22 of optical fibers and a part 8a housing a processing cartridge and equipped with guides for removably receiving a treatment cartridge 8. In FIGS. 1 and 2, the copying machine is illustrated as being loaded with the treatment cartridge 8 in its housing 8a.

 The photosensitive element 2 is housed in the treatment cartridge 8 in the form of a photosensitive drum on which an latent electrostatic image is formed. The treatment cartridge 8 also contains, on the periphery of the photosensitive drum 8, a device 3 for discharging emanations intended to uniformly charge the photosensitive drum 8, a development device 5 equipped with a sleeve 51 intended to carry a developer. to develop the latent electrostatic image on the photosensitive drum 8, a hopper or magazine 52 for storing the developer to be supplied to the developing device 5 before the use of the process cartridge begins, and a processing device 7 cleaning, these elements being arranged in the order indicated, in the direction of rotation of the photosensitive drum 8. They are housed in the form of a block in the treatment cartridge 8.

 The first frame 19 and the second frame 21 can pivot about an axis 20 relative to each other to open or close the copying machine.

The first frame 19 comprises an original carriage 10 intended to carry an original to be copied and capable of causing an alternating movement to be carried out on the original which it carries, over a predetermined stroke, a paper supply tray 12 intended to support one or more transfer or transfer sheets P on which an image of the original is to be formed, a feed roller 13 intended to separate and advance one by one the transfer sheets P, a pair 14 of framing rollers intended to advance the transfer sheet P towards the photosensitive drum 8 in alignment with the developed image formed on this drum 8, a transfer discharge device 6 intended for transferring or transferring the developed image of the photosensitive drum 8 onto the sheet P of transfer, a guide 16 of transport, a pair 17 of rolls of fixing of images intended to fix by heat or by pressure the developed image transferred on the sheet
P to form a permanent image there, and a pair of unloading rollers intended to unload from the main block the transfer sheet now carrying the fixed image. A fan 33 for preventing the device from overheating, a control panel 28 carrying electrostatic devices for controlling the operation of the copying machine and a photosensor 26 for receiving light and producing an electrical signal in response to the light received is also provided, as well as other elements associated with the means mentioned above.

 A photo-switch 29 intended to detect the sheet is fixed on the control panel 28.

A detection lever 30 is pivotally mounted on a shaft 31 fixed to the second frame 21. The lever 30 rotates clockwise when its end 30a is pushed by a transfer sheet P, following whereby the opposite end 30b intersects an optical path of the photo-interrupter 29 to detect the sheet. Instead of the photo-switch 29, a microswitch can be used.

 As is clear from the above, the part intended to house the processing cartridge which contains the photosensitive element and at least one of the other processing means, and the means intended to illuminate the original to be copied, are incorporated in the second frame 21, while the fan 33 and the control panel 28 are housed in the first frame 19. Because of this distribution of the elements, the second frame 21 can be produced in small dimensions and low weight, which reduces the load required when the machine is open or closed.

 The operation of opening the machine will now be described.

 As shown in FIG. 2, the original carriage 10 is moved beyond its alternative stroke for the copy operation t, over a distance such that the top of the second frame 21 is completely exposed. If the original carriage 10 is placed in the rest position shown in FIG. 1, the top of the second frame 21 is completely covered by the carriage 10, so that the machine cannot be opened by mistake. In addition, the boundary between the first frame and the second frame is hidden, which gives a better appearance.

 When the light source and the control panel are housed in different frames, there is another advantage, in addition to the advantages described above, due to the fact that it is possible to minimize the harmful effect, on the control panel, heat produced by the light source. However, there is correspondingly a drawback.

it is known to detect an amount of light coming from the lighting source, and that this amount depends on the density of the image of the original. If the light source and the control panel are placed in different racks, the length of the connection wire going from a photosensor intended to detect the amount of light to the control panel necessarily becomes greater with, as a result, a stronger influence of electrical noise on detection, so that the detection signal does not correctly represent the amount of light received by the photosensor. In addition, when the machine is open and closed, the connection wire can be unintentionally pinched or pinched and therefore deteriorated.

When assembling the machine, the wiring is awkward. To avoid wiring between the first and second frames 19 and 21, it would be possible to provide connectors or relay cards in the immediate vicinity of the border or limit between the frames.

However, the contacts of the connectors or relay cards could then deteriorate during repeated openings and closings of the device with, as a result, an insufficiency of the electrical contacts and therefore the capture of numerous electrical parasites.

 The embodiment illustrated in Figures 1 and 2 provides the solution to these problems.

The bundle 22 of optical fibers has one end 22a placed in the immediate vicinity of the fluorescent tube 11 from which it is spaced by a distance a, and its other end 22b is fixed to an optical fiber support element 23 disposed on an opposite side of the second frame 21. The support element 23 is pivotally mounted on the second frame 21 by means of a first lever 24 and a second lever 25. The photosensor 26 has the effect of detecting the amount of light that it receives fluorescent tube 11 in order to regulate the amount of light. The photosensor 26 is fixed on the control panel 28 and on the first frame 19 by means of a mount 27.

 Figure 3 is a top plan view of the second frame 21. It is advantageous that the end 22a of the fiber is adjacent to the center of the length of the fluorescent tube li when considering the variation in the amount of light at extreme parts of the tube 11. In particular, when the transfer sheet P is advanced so that its center is aligned with the center of the apparatus, the measurement of the quantity of light adjacent to the center is satisfactory even in the case of a small size transfer sheet, because the part of exposure to the image can be measured directly. Measurement in the center is therefore preferable.

 As described, in this embodiment of the invention, the signal is guided optically to the first frame by means of the bundle of light-transmitting optical fibers, so that the transmission of the signal is not influenced by electrical noise. Therefore, the correct signal representing the amount of light can be produced stably. In addition, there is no need to take special care of the wires connecting the first and second frames. The contact to close or open the light transmission path is optical and is therefore less sensitive to noise.

 In addition, since the photosensor is mounted on the control panel, possible noise between the photosensor and the control panel can be avoided.

 With reference to FIG. 4, the description will now relate to the connection between one end 22b of the optical fibers and the photosensor 26. FIG. 5 is a perspective view of this part.

 The element 23 for supporting the optical fibers is supported so as to be able to move substantially vertically on a guide 24a of a first pivoting lever 24. The element. 23 is returned downwards by a leaf spring.

 The first lever 24 is mounted so as to be able to rotate on an axis 25a mounted on a second pivoting lever 25.-An elastic element 24b is produced in one piece with the first pivoting lever 24 and has the effect of retaining this first lever 24 in an intermediate position. Consequently, when the second frame is closed, the end 22b of the fibers is retained in the central position. Similarly, the second pivoting lever 25 is mounted so that it can rotate on the axis of the second frame 21 and is retained in the center by an elastic element 25b.

 The sensor 26 is received by a mount or a sensor support 27 when the second frame 21 is closed relative to the first frame 19. The mount 27 has a guide portion 27a in the form of a funnel having a decreasing cross section towards the sensor 26 in order to guide the optical fiber support element 23 when the second frame 21 is closed on the first frame 19, a part 27b of engagement with the fiber support element 23, intended to position the optical fiber 22b and the photosensor 26, and a stop surface 27c against which an end surface of the optical fiber support member 23 is applied by the force exerted by the leaf spring 32 so that a predetermined gap is established between the optical fiber 22 and the sensor 26.

 In this structure, when the image forming machine is closed, a predetermined interval can be established and maintained between the end surface 22c of the optical fibers 22 and the photosensor 26.

 it is advantageous that the mount 27 of the sensor 26 is equipped with a shutter 34 as shown in FIG. 6 in order to prevent foreign bodies from falling into the guide part 27a and also in order to prevent dust from getting there. accumulate. The shutter 34 is mounted so as to rotate on an axis 35 itself mounted in a vertical wall of the frame 27, and it is normally returned clockwise by return means not shown.

When the copying machine is closed, an end portion 34a of the shutter 34 is pushed down by the element fixed to the second frame 21 so that the shutter 34 is rotated and that it takes a position in which it is shown in solid lines in Figure 6. In this position, the shutter 34 does not oppose the engagement between the frame 27 and the element 23 for supporting the optical fibers. When the copying machine is opened by moving the second frame 21 upwards, the shutter 34 rotates clockwise under the action of the return means in order to assume the position in which it is shown in dashed line in Figure 6, so as to cover the frame 27 from above.

Thus, the upper opening of the mount 27 is covered, so that the light quantity signal can be established stably for a long time.

 Another embodiment of the invention will now be described.

 Referring to Figure 7, there is shown a processing cartridge which can be used with the image forming apparatus described above. The treatment cartridge includes a development device which is not loaded with a developer in FIG. 7. The internal structure of the treatment cartridge is substantially the same as that shown in FIGS. 1 and 2.

 The treatment cartridge comprises a hopper 52, and a closure element 53 is mounted to form a partition between the hopper 52 and the development device 5. By removing the shutter member 53 from the treatment cartridge, the developer contained in the hopper 52 is allowed to pass into the developing device 5, and the developer thus supplied is brought to the sleeve 51 of the developing device 5.

 A resin handle 81 is attached to the shutter 53 so that when the handle 81 is pulled in the direction of arrow A, the shutter member 53 is detached and removed from the process cartridge. The handle 81 protrudes a great distance from a side surface 82 of the process cartridge.

 Figure 8 is a perspective view illustrating the process cartridge mounted in the image forming apparatus. In this figure, the treatment cartridge is placed in the second frame 21 without the closure element 53 being removed. If the user attempts to close the second frame 21 towards the first frame 19, the handle 81 abuts against an upper surface 191 of the first frame 19, because the handle 81 protrudes sufficiently from the lateral surface 82 of the treatment cartridge, as well as it can be seen in FIG. 9, to prevent the second frame 21 from closing completely on the first frame 19. Consequently, in the case of the treatment cartridge whose development device 5 is not yet powered by developer, the copy machine cannot be closed.

We are therefore absolutely opposed to a copy operation by mistake.

 The treatment cartridge, after having been freed from the shutter element 53 and put in place in the second frame, no longer has any part which can be applied to the upper surface of the first frame 19, so that the second frame 21 can be closed on the first frame 19 and that the copying operation can be carried out without error.

 As will be understood from the above, it is possible to prevent any possibility of erroneous printing operations which could otherwise result from the installation in the apparatus of a treatment cartridge whose developing device n is not powered by a developer.

 It goes without saying that many modifications can be made to the device described and shown without departing from the scope of the invention.

Claims (24)

 1. Imaging apparatus, characterized in that it comprises a first assembly (19), a second assembly (21) movable relative to the first assembly for opening and closing the imaging apparatus, a photosensor (26) provided in the first set, lighting means (11) provided in the second set and intended to illuminate an original to be copied, and light transmission means (22) intended to transmit the light emitted by the means in the first set to the photosensor in the second set.  2. Apparatus according to claim 1, characterized in that the light transmission means comprise optical fibers (22) mounted in the second set.  3. Apparatus according to claim 1, characterized in that the second assembly comprises a part (8a) intended to removably house a treatment cartridge (8) which contains a photosensitive element and at least one other treatment means.  4. Apparatus according to claim 3, characterized in that the -premier together comprises an original carriage (10) reciprocating, intended to carry the original.  5. Apparatus according to claim 1, characterized in that the first assembly comprises a table (28) carrying electrostatic elements for controlling the image forming apparatus, the photosensor being mounted on this table.  6. Imaging apparatus, characterized in that it comprises a first assembly (19), a second assembly (21) movable relative to the first assembly for opening and closing the imaging apparatus, a photosensor (26) provided in the first set, lighting means (11) provided in the second set in order to illuminate an original to be copied, a transparent element intended to transmit the light emitted by the lighting means in the first set to the photosensor located in the second set, and a connection part (27) intended to establish a light transmission path from the transparent element to the photosensor when the device is closed, this light transmission path being broken when the device is opened.  7. Apparatus according to claim 6, characterized in that the connection part is arranged in the second set and engages with one end of the light transmitting element and emerges from this end at the same time as the device is closed and it is open, under the effect of the relative movement between the first and second assemblies consisting of frames.  8. Apparatus according to claim 7, characterized in that said end of the light transmitting element is held by a support element (23).  9. Apparatus according to claim 7, characterized in that said end of the light transmitting element can pivot relative to the first assembly.  10. Apparatus according to claim 9, characterized in that the connection part has an opening (27a) whose cross section decreases progressively towards the photosensor.  11. Apparatus according to claim 7, characterized in that the light emitted by the transparent element is received directly by the photosensor.  12. Apparatus according to claim 6, characterized in that it further comprises an element (34) intended to protect the part of the light transmission path which is open when the apparatus is opened under the effect of relative movement between the first and second frames.  13. Apparatus according to claim 12, characterized in that the protective element can move in association with the opening and closing of the apparatus under the effect of the relative movement between the first and second frames.  14. Apparatus according to claim 6, characterized in that the second assembly comprises a part (8a) intended to removably house a treatment cartridge (8) which contains a photosensitive element and at least one other treatment means.  15. Apparatus according to claim 6, characterized in that the first assembly comprises an original carriage (10) å reciprocating movement for carrying the original.  16. Apparatus according to claim 6, characterized in that the first assembly comprises a table (28) carrying electrostatic elements for controlling the image forming apparatus, the photosensor being mounted on this table.  17. An image forming apparatus, characterized in that it comprises a first assembly (19), a second assembly (21) movable relative to the first assembly for opening and closing the apparatus, the second assembly comprising a part ( 8a) housing intended to house a cartridge (8) for processing which comprises at least one development element (5) and a chamber (52) for storing a developer to be supplied to the development device, means (81) being intended to prevent the device from being closed when the developer is not supplied to the developing device in the treatment cartridge housed in said housing part of the second set.  18. Apparatus according to claim 17, characterized in that the treatment cartridge comprises a partition element (53) intended to form a partition between the developing device and the storage chamber, the apparatus being able to close only when the the partition element is removed.  19. Apparatus according to claim 17, characterized in that the treatment cartridge comprises a partition element (53) intended to form a partition between the developing device and the storage chamber, and a handle (81) connected to the partition element in order to facilitate the removal of this element, the handle being able to bear against the first assembly in order to prevent the apparatus from being closed by the relative movement between the first and second frames.  20. Apparatus according to claim 19, characterized in that the handle projects strongly outward from a surface (82) of the process cartridge and can bear against an upper surface of the first set in order to prevent the apparatus to be closed under the effect of the relative movement between the first and second frames.  21. Apparatus according to claim 19, characterized in that it can be closed after the handle has been removed from the treatment cartridge.  22. Treatment cartridge, characterized in that it comprises an element (8) intended to carry an electrostatic latent image, a device (5) intended to develop the electrostatic latent image formed on the image support element, a chamber (52) for storing a developer to supply the developing device, a partitioning element (53) for forming a partition between the developing device and the storage chamber, and a handle (81) projecting from an external boftier of the treatment cartridge in order to facilitate the removal of the partitioning element, the handle projecting strongly outwards from a surface of the housing.  23. Cartridge according to claim 20, characterized in that it further comprises means (3) intended to electrically charge the image support element, and cleaning means (7) intended to remove the developer remaining on the image support member.  24. Cartridge according to claim 22, characterized in that the developer is supplied to the developing means when the partitioning element has been removed from the treatment cartridge by means of said handle.