KR20040074335A - Electro-photographic image forming device and method for detecting opening of covers thereof - Google Patents

Abstract

PURPOSE: An electrophotographic image forming apparatus and a device of sensing opening of the cover of the apparatus are provided to sense opening of the cover using a toner density sensor. CONSTITUTION: An electrophotographic image forming apparatus includes a light scanning unit(125) for scanning light to a photosensitive medium(115), a developing unit(130) for developing an electrostatic latent image formed on the photosensitive medium using a developer, and a transfer unit(140) for transferring a toner image developed using the developer onto print paper. The apparatus further includes a toner density sensor(190) for sensing the density of the toner image, a plurality of switches(160), and a controller. The switches control electricity conduction of a predetermined unit in connection with opening/closing of a developing cover(170) and a duplex cover(180). The controller compares the toner density sensed by the toner sensor with a predetermined reference value, judges that the developing cover and duplex cover to be opened when the toner density is lower than the reference value and outputs a control informing an operator that the covers are opened.

Description

Electro-photographic image forming device and method for detecting opening of covers according to the present invention

The present invention relates to an electrophotographic image forming apparatus and a cover opening detecting method thereof, and more particularly, to an electrophotographic image forming apparatus capable of detecting a cover opening of an image forming apparatus and a cover opening detecting method thereof.

In general, an electrophotographic image forming apparatus scans a charged photosensitive medium with a laser beam to form an electrostatic latent image, develops the electrostatic latent image as a visible image with a developer supplied by a developing apparatus, transfers the image to a paper, and then It uses the electrophotographic printing method to fix with heat and pressure. Such electrophotographic image forming apparatuses include laser printers, copiers, and facsimile machines.

In the electrophotographic image forming apparatus, a hinge-coupled cover is installed as a part of the main body housing to open and close as a housing. The electrophotographic image forming apparatus is provided with a developing cover installed for replacing a developer cartridge or repairing the inside of the main body, and a duplex cover installed for removing and repairing jam paper. In addition, the electrophotographic image forming apparatus is provided with a microswitch for intermittently energizing each unit required for the printing operation and a photosensor for detecting whether the cover is opened or closed.

1 is a view schematically showing a conventional electrophotographic image forming apparatus having a photosensor for detecting a cover opening.

Referring to FIG. 1, a conventional electrophotographic image forming apparatus includes a light source for scanning a paper cassette 10, a photosensitive drum 20, a developing unit 30, and a laser beam onto a photosensitive drum 20 in which printing paper is stored. The transfer unit 50, the fixing unit 60, the micro switch 70, the photosensor 80, etc., which transfer the toner image formed on the photosensitive drum 20 to the recording paper (not shown), etc. Equipped.

The printing process using the electrophotographic image forming apparatus is performed through charging process-> exposure process-> development process-> transfer process-> fixing process. As described above, the print processing using the electrophotographic method can be easily understood by those skilled in the art, and a detailed description thereof will be omitted.

The micro switch 70 controls the energization of the predetermined unit according to whether the developing cover 85 and the duplex cover 90 are opened or closed.

The micro switch 70 drives a predetermined power source (eg, + 24V) supplied from a power supply unit (not shown) according to whether the developing cover 85 and the duplex cover 90 are opened or closed, such as a motor, a solenoid, and a clutch. And a second micro switch for supplying or cutting off the first micro switch for supplying or cutting off to the optical scanning unit 40 and the transfer unit 50 to a predetermined power source (eg, + 5V) supplied from the power supply unit. Equipped.

The first micro switch is provided on the developing cover 85 and the duplex cover 90 by intermittently energizing the driving device, and is connected in series with each other. The second micro switch also includes the developing cover 85 and the duplex cover. It is provided at 90 and is connected in series. Therefore, if any one of the covers 85 and 90 is opened, both of them are implemented to be off. On the inner ends of the developing cover 85 and the duplex cover 90, switch levers 85a and 90a are provided at positions corresponding to the micro switches 70, respectively.

In addition, the photosensor 80 is installed adjacent to the micro switch 70 for controlling the energization of the predetermined unit in accordance with the opening and closing of the developing cover 85 and the duplex cover 90 is the cover (85, 90) Detects the opening of the

The signal detected by the photosensor 80 is transmitted to an engine controller (not shown) that controls the printing operation of the electrophotographic image forming apparatus. When the cover open detection signal is received from the photosensor 80, the engine controller displays the cover open through a display unit (not shown) and simultaneously processes the printing operation of the chemical conversion apparatus. On the other hand, when the cover closing detection signal is received from the photosensor 80, the engine control unit determines that the normal operation state and performs the printing operation.

As described above, the conventional electrophotographic image forming apparatus determines the opening or closing of the developing cover 85 and the duplex cover 90 according to the detection result signal of the photosensor 80 to limit the operation of the image forming apparatus. do.

However, the conventional electrophotographic image forming apparatus has a problem that the unit cost of the image forming apparatus is increased by using a separate photo sensor 80 to detect whether the covers 85 and 95 are opened or closed.

On the other hand, it is possible to detect the opening or closing of the cover using the micro switch 70 without using a separate photosensor 80. For example, a cover is detected by using a micro switch that is energized to a predetermined unit by applying a + 24V power supply, and a cover is used by a micro switch that is energized by a + 5V power supply to regulate a power supply of a predetermined unit. The closing of the can be detected. However, since two input ports for receiving the detection signal of each micro switch 70 should be provided, the PCB pattern design is complicated and the ASIC PIN increases, resulting in a problem that the unit price of the product increases due to the increase in the package. do.

In addition, when the first micro switch receiving + 24V power is turned ON while the contact of the micro switch is ON, and the second micro switch receiving + 5V power is turned OFF, the first micro switch is driven by + 5V power. There is a problem in that the optical scanning unit 40, the transfer unit 50, etc. are not driven to output an error message.

In order to solve the above technical problem, the electrophotographic image forming apparatus according to the present invention is an electrophotograph that can detect the opening of a cover by using a toner concentration detection sensor for detecting the density of the toner image formed on the photosensitive medium. An image forming apparatus and a cover opening detection method thereof are provided.

1 schematically shows a conventional electrophotographic image forming apparatus having a photosensor for detecting a cover opening;

2 is a view schematically showing an electrophotographic image forming apparatus according to a preferred embodiment of the present invention;

3 is a view illustrating a toner concentration detection method using the toner concentration detection sensor of FIG. 2;

4 is a flowchart illustrating a cover open detection method of the electrophotographic image forming apparatus illustrated in FIG. 2.

Explanation of symbols on the main parts of the drawings

100: electrophotographic image forming apparatus 110: paper feed unit

115: photosensitive drum 120: charging unit

125: optical fiber unit 130: developing unit

140: transfer unit 145: fixing unit

150: discharge unit 160: micro switch

170: developing cover 180: duplex cover

190: toner concentration detection sensor

In order to solve the above technical problem, the electrophotographic image forming apparatus according to the present invention comprises a photonic scanning unit for scanning light onto a photosensitive medium, and an electrostatic latent image formed on the photosensitive medium by the optical scanning unit as a developer. A developing unit for developing, a transfer unit for transferring a toner image developed on the photosensitive medium with the developer onto printing paper, a toner concentration detection sensor for detecting the concentration of the toner image formed on the photosensitive medium, and a developer cartridge replacement The toner concentration value detected by the toner concentration detection sensor and a plurality of switching units for intermittent energization of a predetermined unit in conjunction with opening and closing the development cover and the duplex cover installed for removing jam paper are compared with a preset reference value. And the developing cover and the duplex cover are opened when the detected toner concentration value is less than or equal to the reference value. And a control unit for outputting a signal indicating that the cover is opened.

Here, the image density detection sensor is a photosensor, a light emitting unit for emitting a predetermined optical signal to the photosensitive medium to detect the density of the toner image formed on the photosensitive medium and the optical signal incident on the photosensitive medium And a light receiving unit for receiving and outputting the reflected optical signal.

On the other hand, if it is determined that the detected toner concentration value is greater than or equal to the reference value, the controller determines that the developing cover and the duplex cover are closed.

In addition, if it is determined that the developing cover and the duplex cover are closed, the control unit controls to redetect the toner concentration in a state where the light emitting unit is turned off, and covers the detected toner concentration when the redetected toner concentration value is less than or equal to a predetermined value. It is judged to be closed and an error message is output when the redetected toner concentration value is equal to or larger than the predetermined value.

On the other hand, to solve the above technical problem, a developing unit for developing the electrostatic latent image formed by the light scanning unit on the photosensitive medium according to the present invention with a developer, and a toner image developed with the developer on the photosensitive medium for printing paper And a transfer unit for transferring a predetermined amount of the transfer unit, a toner concentration detection sensor for detecting the concentration of the toner image formed on the photosensitive medium, and a plurality of switching units for controlling energization of a predetermined unit in conjunction with opening and closing the development cover and duplex cover. A cover open detection method of an electrophotographic image forming apparatus includes detecting a density of the toner image formed on the photosensitive medium, and comparing the detected toner concentration detection value detected in the toner concentration detection step with a preset reference value. And if it is determined in the comparing step that the toner concentration detection value is equal to or less than the reference value, It is determined that the server and the duplex cover open and pohan the step of controlling to output the signal indicating the cover open.

If the toner concentration detection value is determined to be equal to or greater than the reference value in the comparing step, the control step is performed to redetect the toner concentration with the light emitting unit of the toner concentration detection sensor turned off, and the redetected toner concentration value is If it is less than the predetermined value, it is determined that the cover is closed, and if the re-detected toner concentration value is more than the predetermined value, an error message is output.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Referring to FIG. 2, the electrophotographic image forming apparatus 100 according to the present invention includes a paper feeding unit 110, a photosensitive drum 115, a charging unit 120, a light scanning unit 125, in which printing paper is stored. The developing unit 130, the transfer unit 140, the fixing unit 145, the discharge unit 150, the micro switch 160, the developing cover 170, the duplex cover 180, and the toner concentration detection sensor 190 are removed. Equipped.

The charging unit 120 charges the photosensitive drum 115 applied to the photosensitive medium to a predetermined potential.

The optical scanning unit 125 is controlled by an engine controller (not shown), and scans the light corresponding to the image data transmitted from the image processing unit (not shown) to the photosensitive drum 115. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 115.

The developing unit 130 attaches to the electrostatic latent image formed on the photosensitive drum 115 four color toners of yellow (Yellow, Y), cyan (Cyan, C), magenta (Mgenta, M) and black (Black). A toner image is formed.

The transfer unit 140 transfers the intermediate transfer belt (ITB) 142, which is a moving medium of the toner image formed on the photosensitive drum 115, and the toner image formed on the photosensitive drum 115, to the ITB 142. A first transfer roller 144 for transferring and a second transfer roller 146 for transferring the toner image of the ITB 142 to a printing paper (not shown) are provided.

The transfer unit 140 transfers toner images of Y, C, M, and K colors formed on the ITB 142 onto the recording paper supplied from the paper feeding unit 110.

The fixing unit 145 fixes the image transferred to the recording paper by the transfer unit 140 on the recording paper. The fixing unit 145 is discharged to the outside through the image discharge unit 150 fixed to the recording paper.

The developing cover 170 is installed to open and close the main body of the electrophotographic image forming apparatus 100 for the purpose of replacing the developing cartridge and repairing the inside of the developing cartridge.

The duplex cover 180 is installed to open and close to the main body of the electrophotographic image forming apparatus 100 for the purpose of removing or repairing a recording paper jammed in the discharge unit 150 or the fixing unit 145. . Therefore, when the recording paper is jammed in the delivery unit 150 or the fixing unit 145, the user can open the duplex cover 180 to remove the jammed paper.

Meanwhile, switch levers 172 and 182 are provided at positions corresponding to the micro switches 160, which will be described later, on the inner ends of the developing cover 170 and the duplex cover 180, respectively.

The micro switch 160 controls the energization of a predetermined unit in association with opening and closing of the developing cover 170 and the duplex cover 180. When the developing cover 170 and the duplex cover 180 are closed, the switch levers 172 and 182 provided on the developing cover 170 and the duplex cover 180 are in contact with the micro switch 160 and the micro switch 160. At the same time as to turn on the cover 170, 180 is fixed so as not to open.

More specifically, the micro switch 160 is connected to the opening and closing of the covers 170 and 180 to supply or cut off a power supply of + 24V applied from a power supply unit (not shown) to a predetermined unit 170. A first micro switch (not shown) respectively installed at the 180) and a second micro switch respectively installed at the covers 170 and 180 to supply or cut off a + 5V power applied from a power supply to a predetermined unit. (Not shown). At this time, the + 24V power applied from the power supply unit at the first micro switch turn-on is used as a power supply for driving a driving device such as a motor, a solenoid and a clutch. On the other hand, the + 5V power applied when the second micro switch is turned on is used as a power source for driving the optical scanning unit 125, the transfer unit 140 and the toner concentration detection sensor 190.

The first micro switch installed in the developing cover 170 and the duplex cover 180 is connected in series to automatically turn off when any one of the developing cover 170 and the duplex cover 180 is opened. Like the first micro switch, the second micro switch is also connected in series. On the other hand, the first micro switch and the second micro switch are connected to be driven simultaneously depending on whether the developing cover 170 and the duplex cover 180 is opened or closed. That is, the first micro switch and the second micro switch are connected to be simultaneously turned on or off depending on whether the covers 170 and 180 are opened or closed.

The toner concentration detection sensor 190 detects the density of the toner image formed on the photosensitive drum 115.

FIG. 3 is a block diagram illustrating a toner concentration detection method using the toner concentration detection sensor 190 shown in FIG. 2.

Referring to FIG. 3, the toner concentration detection sensor 190 is installed in the ITB 142. In general, the toner concentration detecting sensor 190 is a CTD light emitting unit which is a light emitting diode that emits a predetermined optical signal to the photosensitive drum 115 in order to detect the density of the toner image formed on the photosensitive drum 115 by a photosensor. 192 and a CTD light receiving unit 194 that receives and outputs a part of the optical signals reflected from the optical signals incident on the photosensitive drum 115.

In addition, the toner concentration detection sensor 190 detects whether the developing cover 170 and the duplex cover 180 are opened or closed, and is applied by the micro switch 160 which performs a switching operation under the control of the engine controller 210. Is driven to the voltage.

The CTD light emitting unit 192 receives an optical signal of the photosensitive drum 115 having the toner image formed thereon to emit a predetermined optical signal to the toner to detect the density of the toner image formed on the photosensitive drum 115. The CTD light receiver 194 may detect the reflection concentration from the photosensitive drum 115.

The signal corresponding to the toner concentration value detected by the CTD light receiver 194 is output to the amplifier 200. The amplifier 200 amplifies a signal corresponding to the toner concentration value output from the toner concentration detection sensor 190. The signal output from the amplifier 200 is input to the A / D converter 205. The A / D converter 205 converts an analog signal corresponding to the toner concentration value amplified by the amplifier 200 into a digital signal. The digital signal converted by the A / D converter 205 is output to the engine controller 210.

Meanwhile, in the present invention, the toner concentration detection sensor 190 detects the toner image formed on the photosensitive drum 115, but the toner image transferred to the ITB 142 or the toner image transferred to the recording paper. Of course, the concentration of can also be detected.

The engine controller 210 controls the charging unit 120, the optical scanning unit 125, the developing unit 130, and the transfer unit 140 under the control of the main controller (not shown) of the electrophotographic image forming apparatus 100. Control the overall operation of the electrophotographic image forming apparatus printing engine unit such as the fixing unit 145, the discharge unit 150, and the micro switch 160.

The engine controller 210 compares the toner concentration value output from the A / D converter 205 with a preset reference value. When it is determined that the toner concentration value is less than or equal to a preset reference value (eg, + 3V), the engine controller 210 recognizes that the developing cover 170 and the duplex cover 180 are open, and signals a cover opening. Output At the same time, the engine controller 210 controls the micro switch 160 to process a predetermined unit driven by receiving a voltage applied from the micro switch 160.

Meanwhile, when it is determined that the toner concentration value detected by the toner concentration detection sensor 190 is greater than or equal to the reference value, the engine controller 210 recognizes that the developing cover 170 and the duplex cover 180 are closed. In this case, the engine controller 210 may control the density of the toner image formed on the photosensitive drum 115 by controlling the developing unit 130 using the toner concentration value detected by the toner concentration detection sensor 190. . As described above, when the toner concentration value detected by the toner concentration detection sensor 190 is greater than or equal to the reference value, the toner concentration formed on the photosensitive drum 115 is controlled by using the detected toner concentration value. Since the same as the control method, a detailed description thereof will be omitted.

In addition, when it is determined that the toner concentration value detected by the toner concentration detection sensor 190 is equal to or greater than a reference value and the covers 170 and 180 are closed, the engine controller 210 controls the micro switch 160 to control the micro switch 160. The CTD light emitting unit 192 of the toner concentration detection sensor 190 is turned off. Then, the engine control unit 210 processes to redetect the toner concentration of the toner image formed on the photosensitive drum 115 while the CTD light emitting unit 192 is turned off.

As a result, when the toner concentration value is redetected by the toner concentration detection sensor 190, the engine controller 210 determines that the toner concentration value redetected by the toner concentration detection sensor 190 is equal to or greater than a predetermined value (for example, 0 V). Determine whether or not. If it is determined that the redetected toner concentration value is OV, the engine controller 210 recognizes that the developing cover 170 and the duplex cover 180 are closed. On the contrary, if it is determined that the redetected toner concentration value is 0 V or more, it is determined that the toner concentration detection sensor 190 is malfunctioning and outputs an error message.

Hereinafter, a method of detecting a cover opening of an electrophotographic image forming apparatus according to an exemplary embodiment of the present invention will be described with reference to FIG. 4.

Referring to FIG. 4, when light is scanned by the optical scanning unit 125 on the photosensitive drum 115 charged by the charging unit 120, the photosensitive drum 115 may be electrostatic latent image by the optical scanning unit 125. Is formed. The toner image developed by the developing unit 130 is formed in the electrostatic latent image forming portion of the photosensitive drum 115.

When the toner image formed on the photosensitive drum 115 arrives at the output position of the CTD light emitting unit 192, the CTD light emitting unit 192 emits a predetermined optical signal to the photosensitive drum 115. The CTD light receiver 194 receives an optical signal reflected from the photosensitive drum 115. As a result, the toner concentration detection sensor 190 detects the density of the toner image formed on the photosensitive drum 115 (S300).

When the toner concentration value of the toner image formed on the photosensitive drum 115 is detected by the toner concentration detection sensor 190, the engine control unit 210 presets the toner concentration value detected by the toner concentration detection sensor 190. It is determined whether the reference value (for example, + 3V) or more (S310). In operation S310, when it is determined that the detected toner concentration value is less than or equal to the preset reference value, the engine controller 210 outputs a message indicating that the cover is opened (S320).

Meanwhile, when it is determined in step S310 that the toner concentration value detected by the toner concentration detection sensor 190 is greater than or equal to the set reference value, the engine controller 210 controls the micro switch 160 to control the CTD of the toner concentration detection sensor 190. The light emitting unit 192 is turned off (S330). Then, the engine control unit 210 processes to redetect the toner concentration while the CTD light emitting unit 192 is turned off (S340).

In addition, the engine controller 210 determines whether the toner concentration value redetected by the toner concentration detection sensor 190 is a predetermined value (for example, 0V) (S350). In operation S350, when it is determined that the redetected toner concentration value is greater than or equal to a predetermined value, the engine controller 210 determines that the toner concentration detection sensor 190 is malfunctioning and outputs an error message (S360).

On the other hand, if it is determined in step S350 that the toner concentration value is less than or equal to a predetermined value, the engine controller 210 recognizes that the developing cover 170 and the duplex cover 180 are closed (S370). If it is determined that the developing cover 170 and the duplex cover 180 are closed, the engine controller 210 determines that the normal operation state is performed and processes the printing operation to be continuously performed (S380).

When it is determined that the developing cover 170 and the duplex cover 180 are closed in the step S310, the developing cover 170 and the duplex cover 180 are actually closed. This is a process performed to determine whether or not the malfunction of the), it does not need to be performed according to the user's selection.

As described above, the electrophotographic image forming apparatus according to the present invention can detect whether the developing cover 170 and the duplex cover 180 are opened or closed by using the toner concentration detection sensor 190. That is, even if the cover 170, 180 is not conventionally provided with a separate photosensor to detect the opening or closing of the development cover 170 and the duplex cover 180 with the toner concentration detection sensor 190 It can be detected.

Although the present invention has been described in detail with reference to exemplary embodiments above, those skilled in the art to which the present invention pertains can make various modifications to the above-described embodiments without departing from the scope of the present invention. I will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

As described so far, according to the electrophotographic image forming apparatus and the cover opening detecting method according to the present invention, it is possible to detect whether the cover installed in the transfer photo image forming apparatus is opened or closed by using a toner concentration detection sensor. It is not necessary to have a cover open detection sensor. As a result, the material cost is reduced, and the cost of the product can be reduced by reducing the material cost.

Claims (6)

A light scanning unit for scanning light onto the photosensitive medium; A developing unit for developing an electrostatic latent image formed on the photosensitive medium by the optical scanning unit with a developer; A transfer unit for transferring a toner image developed on the photosensitive medium with the developer onto a printing paper; A toner concentration detection sensor for detecting a density of the toner image formed on the photosensitive medium; A plurality of switching unit for intermittently energizing the predetermined unit in conjunction with opening and closing the developing cover and the duplex cover installed to remove the jam paper for replacing the developer cartridge; And The toner concentration value detected by the toner concentration detection sensor is compared with a preset reference value, and when the detected toner concentration value is less than or equal to the reference value, it is determined that the developer cover and the duplex cover are open and output a signal indicating a cover opening. An electrophotographic image forming apparatus comprising a control unit. The method of claim 1, The image density detection sensor is a photosensor, A light emitting unit for emitting a predetermined optical signal to the photosensitive medium to detect the density of the toner image formed on the photosensitive medium; And And a light receiving unit for receiving and outputting an optical signal reflected from the optical signal incident on the photosensitive medium. The method of claim 2, And the control unit determines that the developing cover and the duplex cover are closed when it is determined that the detected toner concentration value is greater than or equal to the reference value. The method of claim 3, wherein If it is determined that the developing cover and the duplex cover are closed, the control unit controls to redetect the toner concentration in a state where the light emitting unit is turned off, and closes the cover when the detected toner concentration is less than or equal to a predetermined value. And determine, and output an error message if the redetected toner concentration value is equal to or greater than the predetermined value. A developing unit for developing the electrostatic latent image formed by the light scanning unit on the photosensitive medium with a developer, a transfer unit for transferring a toner image developed with the developer onto the photosensitive medium onto a printing paper, and the toner image formed on the photosensitive medium. A cover open detection method of an electrophotographic image forming apparatus, comprising: a toner concentration detection sensor for detecting a concentration of a; and a plurality of switching units for intermittently energizing a predetermined unit in conjunction with opening and closing of a developing cover and a duplex cover, Detecting a density of the toner image formed on the photosensitive medium; Comparing the toner concentration detection value detected in the toner concentration detection step with a preset reference value; And And determining that the developing cover and the duplex cover are open, and outputting a signal informing that the cover is opened, when it is determined that the toner concentration detection value is less than or equal to the reference value in the comparing step. Cover open detection method of the anti-corrosive image forming apparatus. The method of claim 5, If the toner concentration detection value is determined to be equal to or greater than the reference value in the comparing step, the control step is performed to redetect the toner concentration with the light emitting unit of the toner concentration detection sensor turned off, and the redetected toner concentration value is The cover open detection method of the electrophotographic image forming apparatus, characterized in that it is determined that the cover is closed when it is less than the predetermined value, and that an error message is output when the redetected toner concentration value is more than the predetermined value.