JP4391331B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus equipped with a process cartridge in which two or more of various process means for performing image formation are detachably mounted on a process cartridge frame.

  In an image forming apparatus that forms an image by an electrophotographic method such as a copying machine or a printer, for example, a photosensitive member that is an image carrier, a charging unit that uniformly charges the surface of the photosensitive member, and a photosensitive member are formed on the photosensitive member. Developing means for developing the electrostatic latent image, transfer means for transferring the image on the photoreceptor developed by the developing means to the transfer medium, and developer remaining on the photoreceptor after the transfer of the image to the transfer medium Process means such as cleaning means for removing / collecting the liquid, and at least two or more of the process means are unitized to form a process cartridge, which can be attached to and detached from the apparatus main body, so that the user or maintenance can be performed. A person who performs the process can easily replace the process cartridge.

  However, in such a conventional image forming apparatus, when the process cartridge is replaced, it is necessary to perform an operation after the apparatus is turned off. Therefore, the replacement of the process cartridge has become easy, but the power supply of the apparatus is once cut off during the work. Therefore, in the image forming apparatus in which the fixing unit is heated to a high temperature by the heating element, the cut off power supply is turned off. Even if the process cartridge is replaced (ON) again after the process cartridge is replaced, the temperature of the fixing unit may be lower than the temperature necessary for fixing the image. Therefore, image formation is performed until the temperature rises again to the temperature necessary for fixing. Inconvenience that it was not possible to do.

Therefore, in order to improve this point, a conventional image forming apparatus includes, for example, a power supply unit that supplies power to the process unit and a position that faces the mounting opening of the process unit, as described in Patent Document 1. In some cases, there is provided an energization cut-off means for cutting off the energization from the power supply means to the process unit in accordance with the movement to.
Japanese Patent No. 3037743

In the image forming apparatus described in Patent Document 1, two substantially semicircular unit process units (process means) are opposed to both sides of a photosensitive belt stretched between two rollers. Each of the two process units and the photosensitive belt is arranged so as to be detachable with respect to the photosensitive belt, so that the two process units and the photosensitive belt can be integrally rotated around a rotation shaft provided at an intermediate portion of the photosensitive belt.
Then, by rotating them so that each substantially semicircular process unit is aligned with the substantially semicircular apparatus opening formed on the side surface of the apparatus, each process unit can be removed one by one. When each process unit moves to a position that coincides with the opening of the apparatus, energization from the power supply means to that process unit is cut off.

Therefore, energization from the power supply means to the process unit is interrupted only when the energization interruption condition has a rotating type process unit and the process unit moves to a position that matches the device opening for unit removal. Therefore, there has been a problem that the condition for interrupting the power supply from the power supply means is limited to the shape of the process unit (process cartridge) and the configuration with physical movement.
The present invention has been made in view of the above-described problems, and is not limited to a configuration having a shape or physical movement, and a process cartridge that can be attached to and detached from the apparatus main body is taken out from the apparatus main body. It is an object of the present invention to enable image formation to be resumed immediately after mounting even if it is mounted.

In order to achieve the above object, the present invention provides an image carrier, charging means for uniformly charging the surface of the image carrier, and developing means for developing an electrostatic latent image formed on the image carrier. When cleaning that a transfer unit that the image on the image bearing member is developed by the developing means is transferred to the transfer medium, remove and collect the developer remaining on the image bearing member after the transfer to the transfer medium of the image in the image forming apparatus provided detachably process cartridge detachably unitized to the process cartridge frame to the apparatus main body at least two or more of the process means of the means, the power supply from the power supply A process cartridge-dedicated power switch that shuts off only the process cartridge, detection means for detecting attachment / detachment of the process cartridge to / from the apparatus main body, and Signal corresponding to the attachment and detachment of the process cartridge is inputted from the knowledge unit, the process cartridge based on the signal when it detects that it has been detached from the apparatus main body, the upper Symbol fixing unit power supply to the fixing unit A power supply amount changing means for changing the temperature so as to be higher than a normal set temperature necessary for fixing the image is provided.

According to the process cartridge of the present invention, when the process cartridge is detached from the apparatus main body, the power is supplied to the fixing unit so that the temperature of the fixing unit becomes higher than the normal set temperature necessary for fixing the image. Therefore, it is possible to prevent the temperature of the fixing unit from being lowered when the process cartridge is replaced.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1 is a block diagram showing a power supply system of an image forming apparatus according to the present invention, FIG. 2 is a block diagram showing a power supply system of an image forming apparatus in which inconvenience occurs, and FIG. 3 shows a schematic configuration of the image forming apparatus of FIG. It is a whole block diagram.
A copying machine that is an image forming apparatus shown in FIG. 3 includes a drum-shaped photosensitive member 13 that is an image carrier, a charging device 14 that is a charging unit that uniformly charges the surface of the photosensitive member 13, An exposure device 15 that exposes a charged surface charged by the charging device 14, a developing device 16 that develops an electrostatic latent image formed on the photoreceptor 13, and a toner that is stored in the developing device 16. A toner bottle 17 to be supplied to the transfer device, a transfer device 18 that is a transfer means for transferring an image on the photosensitive member 13 developed by the developing device 16 to a transfer paper P that is a transfer medium, and an image to the transfer paper P Among the process means of the cleaning device 19 that removes and collects the developer remaining on the photoconductor 13 after the transfer and the process means of the static eliminator 20, the photoconductor 13 and one or more of the other process means ( This Is provided detachably process cartridge 10 which is capable unitized removable all processes means described above) to the process cartridge frame 11 to the apparatus main body 1 in the example.

A fixing device 12 for fixing the toner transferred onto the transfer paper P is provided downstream of the process cartridge 10 in the transfer paper transport direction.
In this image forming apparatus, the surface of the photoreceptor 13 is uniformly charged by the charging device 14. Then, the exposure device 15 forms a latent image based on the image data read by the optical reading system 22 provided in the apparatus main body 1. The latent image is developed by the developing device 16 to become a visible image (toner image).

On the other hand, the transfer paper P is fed from the paper feed cassette 27 of the paper feed device 21 provided in the lower part of the apparatus main body 1, and the transfer paper P is conveyed upward along the vertical conveyance path 23 to the transfer device 18. Therefore, the toner image on the photosensitive member 13 is transferred.
The transfer paper P onto which the toner image has been transferred is conveyed to the fixing device 12 where the toner image is fixed, and is then discharged to the external paper discharge tray 31 by the paper discharge roller pair 29. Further, at the time of double-sided image formation, the transfer paper P is conveyed from the reverse conveyance path 32 to the double-sided device 33 by a paper discharge branch claw (not shown), and once stored in the double-sided tray 34, the traveling direction is reversed and double-sided conveyance is performed. The image is formed again on the back surface by being sent from the path 35 to the image forming system having the photosensitive member 13, and is discharged onto the paper discharge tray 31 through the fixing device 12.

After the toner image is transferred onto the transfer paper P, the developer remaining on the photoreceptor 13 is removed and collected by the cleaning device 19 to prepare for the next image formation.
In FIG. 3, only one paper feed cassette 27 is shown to simplify the drawing, but a plurality of paper feed cassettes may be provided as necessary. The image forming apparatus is not limited to a copying machine, and can be applied to a facsimile, a printer, or the like without any trouble.

Each of the process means such as the photosensitive member 13 described above does not require all of them to be detachable from the process cartridge frame 11, but at least two of the process means (for example, those having a relatively short life) are used. The process cartridge frame 11 may be simply detachable.
As shown in FIG. 1, the image forming apparatus includes a process cartridge dedicated power switch (hereinafter simply referred to as a power switch) 5 that cuts off the supply of power from the power supply unit (power supply) 2 only to the process cartridge 10. 2 and the process cartridge 10.
The power supply unit 2 supplies power to the control circuit unit 3 for controlling image formation, and a main switch is provided between the power supply unit 2 and a power supply connection plug 7 for connecting an external power supply. 8 is provided.

In this image forming apparatus, the main switch 8 is closed (ON state) at the time of use. At this time, the process cartridge power switch 5 is closed (ON state). Formation control is performed.
Here, when it becomes necessary to replace the process cartridge 10, the power switch 5 is mechanically or softly opened by the operator. Then, even if the main switch 8 of the image forming apparatus is not cut (opened), the power supply to the process cartridge 10 is surely cut off. Therefore, as shown in FIG. Can be taken out in a safe state.

  Even in this state, since the power switch 5 is a switch that electrically cuts only the process cartridge 10, power supply to the other control circuit unit 3 and the fixing device 12 is maintained. Therefore, while the process cartridge 10 is being taken out from the apparatus main body, power is continuously supplied to each part including the fixing device 12 other than the process cartridge 10, so that the process cartridge 10 is being taken out from the apparatus main body. In addition, the temperature of the fixing device 12 is unlikely to decrease.

Therefore, for example, when the toner runs out and the operation of only replacing the toner bottle 17 shown in FIG. 3 is performed, the toner bottle 17 in the process cartridge 10 taken out from the apparatus main body is replaced with a new one after the toner bottle 17 is replaced with a new one. Even when it is mounted on the main body, the temperature of the fixing device 12 is kept, so that reheating does not take time. Therefore, an unnecessary waiting time for reheating the fixing device 12 can be eliminated.
On the other hand, as shown in FIG. 2, if the process cartridge 10 is not provided with the power switch 5 dedicated to the process cartridge 10 to cut off the supply of power from the power supply unit 2 only, the apparatus main body can be replaced by replacing the process cartridge 10 or the like. When the printer is removed from the printer, the main switch 8 must be disconnected (off state) for safety. However, the power supply to all the image forming apparatuses is stopped.

Accordingly, in this case, the supply of power to the fixing device 12 is also stopped. Therefore, even if the image forming operation is restarted by turning on the main switch 8 after the process cartridge 10 is mounted on the apparatus main body, the fixing is performed. Since the heating of the apparatus 12 is stopped while the main switch 8 is in the OFF state, the image forming operation is performed until the fixing apparatus 12 whose temperature has been lowered is reheated and the temperature is raised to the fixing temperature of the image. Can not resume. Therefore, an unnecessary waiting time occurs.
In contrast, the image forming apparatus according to this embodiment maintains the power supply to the fixing device 12 and maintains the temperature of the fixing device 12 even when the process cartridge 10 is detached from the apparatus main body 1. Therefore, the unnecessary waiting time described above does not occur (reduction of downtime).

FIG. 5 is a front view showing an embodiment of the image forming apparatus in which a dedicated openable / closable cover for taking out the process cartridge from the apparatus main body is provided on the apparatus main body, and parts corresponding to those in FIG. It is.
The image forming apparatus according to this embodiment is provided with a door-shaped cover 37 that can be opened and closed in the direction of arrow A for removing the process cartridge 10 from the apparatus body 1 on the front surface of the apparatus body 1. Different from the image forming apparatus. Further, this image forming apparatus is not directly related to the present invention, but is different from the image forming apparatus of FIG. 3 in that a plurality of (four) sheet feeding devices 21 are provided.

  In this image forming apparatus, the size of the cover 37 that can be opened and closed is set to a minimum size that allows only the process cartridge 10 to be taken out, so that the fixing device 12 is not exposed to the front when the cover 37 is opened. Therefore, since the opening 39 formed in the apparatus main body 1 for providing the cover 37 can be minimized, the heated air near the fixing device 12 escapes to the outside of the apparatus main body 1 when the cover 37 is opened. Can be minimized. Therefore, it helps to maintain the temperature of the fixing device 12.

Further, by making the cover 37 dedicated to the process cartridge 10 in this way, the size of the cover 37 can be reduced to a minimum size that allows the process cartridge 10 to be attached and detached. The open space in front of the apparatus when doing so is small. Therefore, the installation space for the image forming apparatus can be saved.
Further, since the fixing device 12 is not exposed to the front even if the cover 37 is opened, it is possible to prevent the operator from accidentally touching the fixing device 12 heated to a high temperature when the process cartridge 10 is attached or detached. can do.

On the other hand, as shown in FIG. 6 as a conventional image forming apparatus as a comparative example, not only the process cartridge 10 but also the fixing device 12 is opened when the cover 37 ′ is opened because the number of parts is reduced and the overall configuration of the apparatus is easy. If it is exposed at the same time, the heated air in the vicinity of the fixing device 12 also escapes to the outside of the apparatus main body 1. Therefore, even if the image forming operation is restarted after the process cartridge 10 is mounted, the fixing device 12 does not have a predetermined value. The image forming operation cannot be performed until the temperature is raised to a temperature necessary for fixing.
Further, since the cover 37 'becomes large, an open space in front of the apparatus when the cover 37' is opened becomes large, and there is a disadvantage that a large installation space for the image forming apparatus is required.
Further, since the fixing device 12 is exposed when the cover 37 'is opened, there is a possibility that an operator accidentally touches the fixing device 12 heated to the high temperature and is burned.

FIG. 7 is a front view showing an embodiment of the image forming apparatus in which a dedicated openable / closable cover for removing the process cartridge from the apparatus main body is provided on the large cover so as to be openable / closable. The code | symbol is attached | subjected.
In the image forming apparatus according to this embodiment, a dedicated door-shaped cover 37 for taking out the process cartridge 10 from the apparatus main body 1 can be opened and closed in the direction of arrow A on a large cover 38 that can be opened and closed with respect to the apparatus main body 1. Provided.
Even in this case, the same effect as the image forming apparatus described in FIG. 5 can be obtained.

FIG. 8 is a front view similar to FIG. 5 showing an embodiment of the image forming apparatus in which power supply to the process cartridge is cut off when the cover is opened. Are given the same reference numerals.
In this image forming apparatus, the power switch 5 is disposed in the vicinity of the hinge portion of the cover 37, and the power switch 5 is operated so as to cut off the supply of power to the process cartridge 10 when the cover 37 is opened (power). In the supply cutoff state), the power supply to the fixing device 12 is maintained, and the temperature of the fixing device 12 is maintained.

  Accordingly, when the cover 37 is opened, the supply of power to the process cartridge 10 is automatically cut off in conjunction with the opening, so that the process cartridge 10 remains in a state where the main switch of the image forming apparatus is turned on (on state). Even if the cartridge is taken out from the apparatus main body 1 by replacement or the like, the process cartridge 10 in the unpowered state is not taken out. As a result, the operator can easily and safely maintain the process cartridge 10.

FIG. 9 is a block diagram similar to FIG. 1 showing an embodiment of the image forming apparatus in which the power supply to the fixing unit is changed when the process cartridge is detached from the apparatus main body, and corresponds to FIG. The parts are given the same reference numerals.
In this image forming apparatus, when the process cartridge 10 is detached from the apparatus main body, the power supply to the fixing device 12 is changed so that the fixing device 12 has a set temperature higher than the normal set temperature. A power supply amount changing unit 4 that functions as an amount changing means is provided. In addition, a sensor (for example, a reflective photosensor) 6 that detects attachment / detachment of the process cartridge 10 to / from the apparatus main body is provided.

The power supply amount changing unit 4 receives a sensor signal corresponding to the attachment / detachment of the process cartridge 10 from the sensor 6, and when it is detected from the sensor signal that the process cartridge 10 has been removed from the apparatus main body, the fixing device 12. The fixing device 12 is controlled to have a set temperature higher than a normal set temperature by increasing the amount of power supplied to the printer.
The power supply amount changing unit 4 determines whether or not to change the set temperature of the fixing device 12 according to the sensor signal from the sensor 6, and the fixing device according to a command from the microcomputer. 12 includes a fixing device driving circuit for heating 12.

Incidentally, the fixing device 12, as shown in FIG. 10, on and at the same time heating of the main switch of the image forming apparatus is overheated, the temperature rises as shown in the time domain T _1. Then, as shown in the time domain T ₁ time domain T ₂ After a predetermined time has elapsed, the image settings usually required for fixing the temperature T (hereinafter, simply referred to as the set temperature T) is controlled to be maintained Is done.
In the image forming apparatus of this embodiment as well, the power supply to the fixing device 12 is maintained when the process cartridge 10 is detached from the apparatus main body, as in the image forming apparatus described above. Even when the process cartridge 10 is detached from the apparatus main body, the power supply to the fixing device 12 is continued.

However, in order to remove the process cartridge 10 from the apparatus main body by replacement or the like, it is necessary to open an openable / closable cover (the image forming apparatus is also provided with the cover 37 described with reference to FIG. 5). air heated within the apparatus main body by escaping to the outside of the apparatus, the temperature of the fixing device 12 as shown in the time domain T ₃ in FIG. 10 is reduced to.
In this case, the control system of the fixing device 12 performs control for maintaining the fixing unit temperature at the set temperature T. Thereby, temporarily fixing unit temperature in the portion of the time domain T ₃ drops below the set temperature T, but even if the process cartridge 10 is detached from the apparatus main body when it is time domain T _4, the fixing unit temperature It returns to the set temperature T.

However, when a new process cartridge 10 for replacement is attached to the main body of the apparatus, heating of the fixing device 12 is controlled at the same temperature as the normal set temperature (fixing temperature) T at that time. as shown in the time domain T ₅ in FIG. 10, a fixing unit temperature falls below the set temperature T again.
This is because the new process cartridge 10 has a lower temperature than the temperature of the heated air in the apparatus main body, so that the process cartridge 10 itself takes the temperature in the apparatus main body and the temperature of the fixing device 12. It is to become. Therefore, immediately after the new process cartridge 10 is attached to the apparatus main body, the fixing unit temperature may be lowered (below the temperature necessary for fixing the image), so the image forming operation may not be resumed immediately. .

  However, in the image forming apparatus of this embodiment, as described with reference to FIG. 9, the power supply amount changing unit 4 is provided, and a sensor signal corresponding to the attachment / detachment of the process cartridge 10 is input from the sensor 6. When it is detected that 10 has been removed from the apparatus main body, the amount of power supplied to the fixing device 12 is increased, and the fixing device 12 is controlled to have a set temperature T ′ higher than the normal set temperature T. Therefore, it is possible to prevent a temperature drop when the process cartridge is attached.

That is, when the process cartridge 10 is removed from the apparatus main body, the amount of power supplied to the fixing device 12 is increased, and the fixing device 12 is controlled to have a set temperature T ′ higher than the normal set temperature T. it can continue maintaining the fixing unit temperature in the time domain T ₅ by the higher temperature the time domain T ₄ in FIG. 11 to the normal set temperature T. Thereby, the image forming operation can be resumed immediately after the process cartridge 10 is replaced. Therefore, the downtime of the entire apparatus can be reduced.

FIG. 12 is a front view similar to FIG. 8 showing an embodiment of the image forming apparatus in which the power supply to the fixing unit is changed when the process cartridge removal cover is in the open state. Portions corresponding to 9 are given the same reference numerals.
This image forming apparatus is different only in that the sensor 6 described in the embodiment of FIG. 9 is used as a sensor for detecting the opening / closing of the cover 37 of the image forming apparatus described in FIG.
Therefore, the image forming apparatus according to this embodiment also supplies power to the fixing device 12 when the cover 37 is opened, and the fixing device 12 has a set temperature higher than the normal set temperature T described in FIG. There is provided a power supply amount changing unit 4 which is a power supply amount changing means for changing to T ′.

  According to this image forming apparatus, when the cover 37 is opened when the process cartridge 10 is removed from the apparatus main body 1, the set temperature of the fixing device 12 or the normal set temperature T is immediately changed to a higher set temperature T ′. Therefore, it is possible to prevent the fixing unit temperature from lowering than the normal set temperature T. Thereby, the image forming operation can be resumed immediately after the process cartridge 10 is replaced. Accordingly, the downtime of the entire apparatus can be reduced also in this image forming apparatus.

Although the embodiments of the image forming apparatus according to the present invention have been described above, for example, in the image forming apparatus of the embodiment described with reference to FIG. 1, the power supply from the power supply unit 2 to the process cartridge 10 is cut off by the power switch 5. It is also effective if the control circuit unit 3 functions as means for continuing power supply to each unit that performs pre-processing related to image formation.
In this way, when the process cartridge 10 is replaced, not only the above-described control for maintaining the fixing unit temperature but also a normal control circuit that performs preprocessing for image formation can continue normal operation. Processing other than the processing related to formation can be continued.
For example, in the case of a copying machine, a document taking operation or the like is continued without interruption. In the case of a printer, print data is transferred from the host. Thereby, the image forming operation can be resumed immediately after the process cartridge 10 is mounted. Therefore, the downtime of the entire apparatus can be greatly reduced.

  The present invention can be widely applied to image forming apparatuses such as copiers and printers equipped with a process cartridge in which two or more of various process means for performing image formation are detachably unitized with respect to a process cartridge frame. it can.

1 is a block diagram showing a power supply system of an image forming apparatus according to the present invention. FIG. 3 is a block diagram illustrating a power supply system of an image forming apparatus in which inconvenience occurs. FIG. 2 is an overall configuration diagram illustrating a schematic configuration of the image forming apparatus in FIG. 1. FIG. 2 is a schematic view showing a state where a process cartridge is removed from the image forming apparatus. FIG. 2 is a front view showing an embodiment of an image forming apparatus in which a dedicated openable / closable cover for taking out a process cartridge from the apparatus main body is provided in the apparatus main body. It is a front view similar to FIG. 5 for demonstrating the inconvenience which arises when a cover is large.

FIG. 3 is a front view showing an embodiment of an image forming apparatus in which a dedicated openable / closable cover for taking out a process cartridge from the apparatus main body is provided on a large cover so as to be opened and closed. FIG. 6 is a front view similar to FIG. 5 showing an embodiment of an image forming apparatus in which power supply to a process cartridge is cut off when a cover is opened. FIG. 2 is a block diagram similar to FIG. 1 showing an embodiment of an image forming apparatus in which the power supply to the fixing unit is changed when the process cartridge is detached from the apparatus main body. It is a diagram for explaining a temperature transition of the fixing device. FIG. 10 is a diagram showing a temperature transition in the fixing device of the image forming apparatus shown in FIG. 9. FIG. 9 is a front view similar to FIG. 8 showing an embodiment of the image forming apparatus in which the power supply to the fixing unit is changed when the process cartridge removal cover is in an open state.

Explanation of symbols

1: mounted main body 2: power supply unit (power supply) 3: control circuit unit 4: power supply amount changing unit (power supply amount changing means) 5: process cartridge dedicated power switch 10: process cartridge 11: process cartridge frame 12: fixing Device (fixing unit) 13: Photoconductor (image carrier) 14: Charging device 15: Exposure device 18: Transfer device 19: Cleaning device 37, 37 ′: Cover

Claims (1)

An image carrier, a charging unit for uniformly charging the surface of the image carrier, a developing unit for developing an electrostatic latent image formed on the image carrier, and the image developed by the developing unit. At least one of the process means of a transfer means for transferring an image on the carrier to a transfer medium, and a cleaning means for removing and collecting the developer remaining on the image carrier after the transfer of the image to the transfer medium. In an image forming apparatus in which two or more process cartridges that are detachably attached to a process cartridge frame are provided to be detachable from an apparatus main body.
A process cartridge dedicated power switch that cuts off the supply of power from the power source only to the process cartridge;
Detecting means for detecting attachment / detachment of the process cartridge to / from the apparatus main body;
Wherein the signal corresponding to the detachment of the process cartridge from the sensing means input, when the process cartridge on the basis of the signal is detected to be removed from the apparatus main body, the front Symbol fixing unit power supply to the fixing unit Power supply amount changing means for changing the temperature so that the temperature becomes higher than the normal set temperature required for fixing the image ;
An image forming apparatus comprising:

Images