JP2000010457A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which prevents, even at the time of the detachment of a process cartridge from a main body to which it has been attached, the device from being rendered unusable due to a static- charge release phenomenon or an image from deteriorating and which is provided with a simple, convenient mechanism for detecting the attachment/ detachment of the process cartridge. SOLUTION: When the process cartridge 26 is detached from the main body to which it has been attached, a power-feed terminal 82 is grounded by a frame ground 86, therefore even in the case an operator charged with static electricity touches the power-feed terminal 82, the static electricity of the operator does not exert effect on the image forming device. Also, because a circuit on the side of the process cartridge 26 is short-circuited by the application of a voltage to the power-feed terminal 82, the detachment of the process cartridge 26 can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with an image forming cartridge detachably mountable to an apparatus main body.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus provided with a cartridge for image formation which is detachably mountable to an apparatus main body, when the cartridge is removed from the apparatus main body, a cartridge provided in the apparatus main body is provided. A power supply terminal for supplying high-voltage power to the battery is exposed.

A cartridge for forming an image includes a process cartridge having a photosensitive drum, a developing cartridge having a developing device for supplying toner to the photosensitive drum, and a method for fixing a toner image on a sheet onto which a toner image has been transferred. For example, there is a fixing cartridge including a fixing device for performing the fixing.

[0004] Here, as one of the international standards for noise immunity required for information processing equipment, "static test requirements:
IEC801-2 ".

[0005] This "static test requirement: IEC801-
In the test of 2), the charge energy stored in the capacitor inside the tester is applied from the discharger to the EUT through a specified resistor, and the malfunction of the EUT is confirmed.

It is another object of the present standard to prevent an accident due to an electromagnetic environment disturbance represented by static electricity discharge from a charged human body.

According to this standard, focusing on the location where static electricity is applied to the EUT, there is "the surface of equipment that can be touched by an operator during normal use (including the maintenance range by the operator)".

Here, when this standard is applied to the above-described image forming apparatus, not only the metal part on the outer surface of the apparatus but also the power supply terminal of the apparatus main body for supplying high voltage power to the cartridge. Be eligible for the test. This is because the power supply terminal on the main unit is usually exposed, and its surface is maintained by the operator (paper jam removal, cartridge replacement, etc.).
When the static electricity is applied to the power supply terminal and the voltage of several kilovolts required in this test is applied, the high-voltage power supply circuit and the central processing unit cannot be used. Further, when the cartridge is a process cartridge, the image signal to the photosensitive drum to be charged and exposed is also hindered, and the image may be deteriorated.

For this reason, a method has been devised by a method disclosed in Japanese Patent Application Laid-Open No. 7-77921 so that the power supply terminal is not touched by an operator's hand. Specifically, in the image forming apparatus 200 as shown in FIG. 9, when the process cartridge 202 is mounted on the cartridge mounting portion 204 of the apparatus main body 203 as shown in FIG.
06 is pushed by the mounting guide member 208, and the power supply terminal 212 is exposed from the window 210. On the other hand, when the process cartridge 202 is removed from the apparatus main body 203 as shown in FIG. 11, the power supply terminal 212 is covered with the insulating protection plate 206 so that the worker does not contact the power supply terminal 212.

When a printing operation is performed in a state where the process cartridge 202 is detached from the apparatus main body 203, the fed paper remains in the image forming apparatus 200 without being printed. Therefore, the process cartridge 202
A mechanism for detecting attachment / detachment is required.

In this apparatus, the process cartridge 202
Is attached to the apparatus main body 203, the grounded terminal 214 on the insulating protection plate 206 comes into contact with the terminal 216 to which a voltage of 3V is applied.
become. Thus, the attachment / detachment of the process cartridge 202 can be detected.

[0012]

However, in the conventional structure, a dedicated terminal for detecting whether or not the cartridge is mounted on the image forming apparatus main body is operated by a dedicated mechanism, so that the detection mechanism is complicated. It also increases costs.

An object of the present invention is to provide a mechanism for simply detecting the attachment / detachment of a cartridge to / from an image forming apparatus main body in consideration of the above fact.

[0014]

According to a first aspect of the present invention, there is provided a cartridge which is configured to be detachable from an apparatus main body and which is supplied with high-voltage power for image formation, and which is provided in the apparatus main body. A power supply unit for supplying high-voltage power for image formation when the cartridge is mounted, and a power supply terminal for removing the cartridge from the apparatus main body. And grounding means for grounding the power supply terminal to the frame ground, and detecting means for detecting a grounding state of the power supply terminal to the frame ground.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the power supply terminal is grounded to the frame ground by the urging force of the urging means, and the mounting of the cartridge is performed by the urging means. The power supply terminal is displaced against the biasing force of (1), and the grounding to the frame ground is released.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the detection unit applies a voltage to the power supply terminal, and a circuit of the power supply unit. And determination means for determining whether or not is short-circuited.

According to the first to third aspects of the present invention, if the grounding state of the power supply terminal to the frame ground is detected, the presence or absence of the mounting of the cartridge can be detected.
There is no need to provide a dedicated terminal for detection, and a mechanism for detecting the attachment / detachment of the cartridge can be easily provided.

[0018]

FIG. 1 shows a schematic overall configuration diagram of a laser beam printer 10 as an image forming apparatus according to an embodiment of the present invention.

The laser beam printer 10 is connected to an image information output device such as a computer to create recording paper.

As shown in FIG. 1, a laser beam printer 1
0, the image processing apparatus 14 that receives image information from a computer or the like and outputs image writing information, a control device 16 that controls the operation of each device of the laser beam printer 10, a high-voltage power supply 18, And low voltage power supply 2
0 is provided.

On the front side of the apparatus main body 12, a front cover 24 which can be opened and closed with respect to the apparatus main body 12 through a hinge 22, and a process for forming an image which is detachable from the apparatus main body 12 are provided. A cartridge 26 is provided.

Here, the process cartridge 26 includes:
The photosensitive drum 28, the developing device 30, a charge roll 32 that uniformly charges the photosensitive drum 28 by discharging, and a toner that is supplied to the photosensitive drum 28 to be visible on the photosensitive drum 28 Developing device 3 for forming an image
A cleaning device 36 that cleans the toner remaining on the developing roller 34 and the photosensitive drum 28 in the area 0 is provided. Then, inside the front cover 24, the photosensitive drum 28
A transformer roll 38 for transferring a toner image to a sheet by discharging is provided on the opposite side of the printer, and in the apparatus main body 12 and near the process cartridge 26,
An eraser lamp 40 for irradiating the photosensitive drum 28 with light to remove the remaining charge is provided.

The apparatus main body 12 is provided with a laser scanning device 44 for irradiating image writing information from the image information processing device 14 to the image writing section 42 of the photosensitive drum 28 with a laser. . Here, a laser light output device (not shown), a polygon mirror 46, an fθ lens 48, a mirror 50,
52 are provided.

Further, a fixing device 54 for fixing the toner image transferred from the photosensitive drum 28 to a sheet is disposed at the upper front of the apparatus main body 12, and a heating roller 56 for melting the toner is provided in the fixing device 54. And a pressure roller 58 for pressing the melted toner against the sheet.

At the lower part of the apparatus main body 12, a cassette tray 60 for supplying paper and a paper feeding section 62 for mounting the cassette tray 60 are arranged.
The paper feed roller 64 is disposed in the paper feed section of the printer.
Further, a transport roller device 66 for transporting the sheet sent from the cassette tray 60 toward the photosensitive drum 28 and a registration roller device 68 are provided. Further, a discharge roller device 72 for discharging the sheet passing through the fixing device 54 to the discharge tray 70 is provided.

Here, the registration roller device 68, the trans-roll 38, and the fixing device 54
The paper conveyance path to the discharge roller 72 through the paper feed member is constituted by a paper guide member disposed on a frame on the front side of the mounting body 12 and a member inside the front cover 24 which can be opened and closed via the hinge 22. Is done. Therefore, when a paper jam occurs in the paper transport path, the paper in the paper transport path can be easily taken out by opening the front cover 24.

Further, the process cartridge 26 is provided in the middle of the sheet transport path, and maintenance and replacement of the process cartridge 26 can be performed by opening the front cover 24.

Also, as shown in FIG.
A cartridge mounting portion 74 for mounting the process cartridge 26 is provided, and a cartridge receiving portion 75 is provided on both sides of the cartridge mounting portion 74. And
The cartridge receiving portion 75 includes the process cartridge 26.
A groove-shaped guide portion 76 is provided for positioning. On the other hand, the side plate 78 of the process cartridge 26 includes
A mounting guide member 80 having a shape corresponding to the groove-shaped guide portion 76 of the cartridge mounting portion 74 is provided.

Then, the mounting guide member 80 of the process cartridge 26 is moved to the groove-shaped guide portion 7 of the cartridge receiving portion 75.
6 and the process cartridge 26 is
By pushing in the direction, the process cartridge 26 can be mounted on the apparatus main body 12.

The cartridge receiving portion 75 has a movable power supply terminal 82 for supplying high-voltage power to the process cartridge 26, and a groove-shaped power supply terminal 82 provided in parallel with the groove-shaped guide portion 76 for guiding the movement of the power supply terminal 82. Guide 84 for power supply terminal
Are arranged. Here, the power supply terminal 82 is fitted in a groove-shaped power supply terminal guide 84, and the power supply terminal 82 can move along the power supply terminal guide 84.

Further, inside the cartridge receiving portion 75, a frame ground 86 for grounding the power supply terminal 82,
And a tension coil spring 88 attached to the power supply terminal 82
Are arranged. The tension coil spring 88 is urged in the direction of the frame ground 86, and when the process cartridge 26 is not mounted, the power supply terminal 8
2 is in contact with the frame ground 86.

On the other hand, the process cartridge 26 is provided with a power receiving terminal 90 at a position corresponding to the power supply terminal 82. When the process cartridge 26 is mounted on the apparatus main body 12, the power receiving terminal 90 is connected to the power supply terminal 82. The power receiving terminal 90 can receive high-voltage power from the power supply terminal 82.

FIG. 3 is a block diagram for detecting whether or not the process cartridge 26 is mounted on the apparatus main body 12.

As shown in FIG. 3, the control device 16 includes the CPU 1
1, a RAM 13, a ROM 15, and an I / O port 17, which are interconnected by a bus.

The I / O port 17 of the control device 16
Is connected to a high-voltage power supply 18 that supplies power to the power supply terminal 82, and a current detection circuit 92 that detects a current flowing from the high-voltage power supply 18 is provided between the power supply terminal 82 and the high-voltage power supply 18. I have. Note that the current detection circuit 92 also
/ O port 17.

Further, a control panel 94 provided in the apparatus main body 12 is connected to the I / O port 17. Here, the control panel 94 displays not only a display for operating the laser beam printer 10 but also a display that the process cartridge 26 is not mounted on the apparatus main body 12.

The operation of attaching and detaching the process cartridge 26 to and from the apparatus main body 12 will be described below with reference to FIGS.

As shown in FIG. 4, the process cartridge 26
When the power supply terminal 82 is detached from the apparatus main body 12, the power supply terminal 82 of the cartridge receiving portion 75 is connected to the frame ground 86 by the urging force of the extension coil spring 88, and the power supply terminal 82 is grounded.

Therefore, even if the worker comes into contact with the power supply terminal 82, the charged static electricity is released to the worker,
The high-voltage power supply circuit and the CPU 11 do not become unusable. Further, the image signal to the photosensitive drum 28 to be charged and exposed is not hindered, and the image is not deteriorated.

As described above, according to this embodiment, one of the international standards for noise immunity required for information processing equipment is described.
The two requirements of "Electrostatic test requirement: IEC801-2" can be satisfied.

On the other hand, as shown in FIG. 5, the mounting guide member 80 of the process cartridge 26 is
When the process cartridge 26 is mounted on the apparatus main body 12 along the groove-shaped guide portion 76, the power receiving terminal 90 of the process cartridge 26 presses the power supply terminal 82 of the cartridge receiving portion 75, thereby urging the tension coil spring 88. The power supply terminal 82 moves along the power supply terminal guide 84 against the pressure. Then, the power supply terminal 82 is not connected to the frame ground 86.

Therefore, the power receiving terminal 90 of the process cartridge 26 can receive high-voltage power from the power supply terminal 82.

When the process cartridge 26 is detached from the apparatus main body 12, the power supply terminal 82 moves along the power supply terminal guide 84 according to the urging force of the extension coil spring 88, and the process cartridge 26 is detached from the apparatus main body 12. At this time, the power supply terminal 82 is connected to the frame ground 86 as shown in FIG.

The operation of detecting whether or not the process cartridge 26 is mounted will be described below with reference to FIG.

The detection of whether or not the process cartridge 26 is mounted is always performed as a pre-print job before the laser beam printer 10 starts printing.

When the power of the laser beam printer 10 is turned on, a pre-print job starts in step 100 of FIG.
From 8, a high voltage is applied to the power supply terminal 82 of the mounting body 12. Then, in step 104, when the short circuit of the high voltage power supply circuit is detected by the current detection circuit 92, the process cartridge 26 of the high voltage power supply circuit is supplied through the power supply terminal 82.
Since the side is short-circuited with the frame ground 86, the CPU 11 determines in step 106 that the process cartridge 26 is not mounted. In step 108, an error message is output from the I / O port 17, and the control panel 94 indicates that the process cartridge 26 is not mounted.

On the other hand, if the short circuit of the high voltage power supply circuit is not detected by the current detection circuit 92 in step 104, the power supply terminal 82 of the apparatus main body 12 is in the state of being connected to the power reception terminal 90 of the process cartridge 26. In step, the CPU 11 determines that the process cartridge 26 is mounted, and enters a print standby state in step 112.

As described above, since the presence or absence of the process cartridge 26 can be detected before the start of printing, the printing operation is started in a state where the process cartridge 26 is not mounted, and the paper is fed to the laser beam printer 10. The paper is not printed and the laser beam printer 1
It does not remain inside 0.

Further, in this embodiment, a dedicated terminal for detecting the presence / absence of the mounting of the process cartridge is not operated by a special mechanism unlike the conventional apparatus. A detection mechanism can be easily provided.

In the present embodiment, a combination of the photosensitive drum 28, the developing device 30, the charge roll 32, and the cleaning device 36 is used for the process cartridge 26, but an arbitrary device is combined as the process cartridge. A thing may be used.

Further, in the present embodiment, the process cartridge 26 having the photosensitive drum 28 and the like is structured so as to be detachable from the apparatus main body 12. However, a developing cartridge comprising a developing device for supplying toner to the photosensitive drum is provided. A fixing cartridge or the like including a fixing device for fixing a toner image on a sheet onto which a toner image has been transferred is configured to be detachable from the apparatus main body 12, and the apparatus main body 1 has the same structure as that of the present embodiment.
2 may be attached.

In this embodiment, as shown in FIG.
Although the tension coil spring 88 urged in the direction of the frame ground 86 to move the power supply terminal 82 is used to extend the tension coil spring 88 when the process cartridge 26 is mounted as shown in FIG. Coil spring 8
8, instead of the frame ground 86 as shown in FIG.
Using a compression coil spring 96 biased in the direction shown in FIG.
As described above, the compression coil spring 96 may be compressed when the process cartridge 26 is mounted.

Further, in the present embodiment, the apparatus body 12
Although the power supply terminal 82 can be moved, the power supply terminal may be fixed, and the frame ground may be moved by the urging force of the urging means.

[0054]

According to the first to third aspects of the present invention, the presence or absence of the cartridge can be detected by detecting the grounding state of the power supply terminal to the frame ground. There is no need to provide a terminal, and a mechanism for detecting the attachment / detachment of the cartridge can be easily provided.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of a laser beam printer according to the present embodiment.

FIG. 2 is a configuration diagram of a main body of a laser beam printer and a process cartridge.

FIG. 3 is a configuration diagram of a process cartridge.

FIG. 4 is a configuration diagram when a process cartridge is detached from a main body of the laser beam printer (when a tension coil spring is used).

FIG. 5 is a configuration diagram when a process cartridge is mounted on the main body of the laser beam printer (when a tension coil spring is used).

FIG. 6 is a flowchart for detecting whether a process cartridge is mounted.

FIG. 7 is a configuration diagram when a process cartridge is detached from a main body of the laser beam printer (when a compression coil spring is used).

FIG. 8 is a configuration diagram when a process cartridge is mounted on the main body of the laser beam printer (when a compression coil spring is used).

FIG. 9 is a schematic diagram of a conventional image forming apparatus.

FIG. 10 is an explanatory diagram when a process cartridge is mounted in a conventional image forming apparatus.

FIG. 11 is an explanatory diagram of a conventional image forming apparatus when a process cartridge is attached and detached.

FIG. 12 is a circuit diagram for detecting attachment / detachment of a process cartridge in a conventional image forming apparatus.

[Explanation of symbols]

 Reference Signs List 10 laser beam printer (image forming apparatus) 18 high voltage power supply (voltage applying means) 26 process cartridge 82 power supply terminal 86 frame ground (grounding means) 88 tension coil spring (biasing means) 92 current detection circuit (discriminating means)

Claims (3)

[Claims] 1. An image forming apparatus, comprising:
A cartridge to which high-voltage power is supplied for image formation; and a power supply terminal provided in the apparatus main body and connected to the cartridge-side terminal when the cartridge is mounted, and supplies high-voltage power for image formation. Power supply means, a grounding means for grounding the power supply terminal to a frame ground as the cartridge is removed from the apparatus main body, and a detection means for detecting a grounding state of the power supply terminal to the frame ground. Image forming device. 2. The power supply terminal is grounded to the frame ground by the urging force of an urging means, and the mounting of the cartridge shifts the power supply terminal against the urging force of the urging means, and The image forming apparatus according to claim 1, wherein the grounding is released. 3. The power supply device according to claim 1, wherein the detection unit includes: a voltage application unit configured to apply a voltage to the power supply terminal; and a determination unit configured to determine whether a circuit of the power supply unit is short-circuited. Or the image forming apparatus according to claim 2.