JP2018005056A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of quickly detecting whether the change of a voltage level on an interlock switch poststage side is caused by the opening of a door or the abnormality of a power system.SOLUTION: The image forming apparatus includes an apparatus body, the door, voltage output means for outputting a first voltage and a second voltage, image forming means to which the first voltage is supplied, a switch for cutting off the first voltage supplied to the image forming means according to the opening of the door, detection means which is arranged in the door and is for detecting a recording material, and control means to which the second voltage is supplied. The control means determines that the door is opened, when a detection result by the detection means is changed in a predetermined period before and after the timing when the level of the first voltage between the switch and the image forming means becomes lower than a predetermined threshold and determines that a commercial power supply or the voltage output means is abnormal, when the detection result is not changed.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines and printers are provided with a door for replacing a cartridge or removing a jammed recording material. When the door is opened, the user can access the inside of the apparatus main body. Therefore, the supply of voltage from the power supply is often automatically cut off by the interlock switch.

  Patent Document 1 describes a power supply apparatus that outputs two systems of voltages, a drive system voltage supplied to a motor or the like and a control system voltage supplied to an engine controller or the like. An interlock switch is arranged on a line where a drive system voltage is supplied from a power supply device to a motor or the like, and the drive system voltage is cut off when the door is opened. The engine controller detects that the door has been opened by monitoring the voltage level on the rear stage side of the interlock switch.

JP2004-138893

  Here, the voltage level on the rear stage side of the interlock switch also decreases when a power supply system abnormality such as a voltage fluctuation of a commercial power supply or an instantaneous power failure occurs. The threshold for the engine controller to detect such an abnormality in the power supply system is often set low in consideration of the influence of noise and the like. On the other hand, the threshold value for detecting that the door has been opened is often set high so that the engine controller can quickly stop other motors that are not linked to the interlock switch.

  Therefore, in the configuration of Patent Document 1, when the power supply system abnormality occurs and the voltage level decreases, the door is not actually opened before the engine controller detects the power supply system abnormality. There is a possibility of false detection that the door is open. Thereafter, when the voltage level further decreases, the engine controller can detect an abnormality in the power supply system.

  Here, if the engine controller erroneously detects that the door is open, the engine controller also stops other motors and the like that are not linked to the interlock switch, so the load on the entire drive system is reduced. Therefore, there is a problem that the speed at which the level of the drive system voltage decreases is slow, and the time until the abnormality of the power supply system can be detected becomes long.

  An object of the present invention is to provide an image forming apparatus that can quickly detect whether a voltage level change on the rear stage side of an interlock switch is caused by a door open or a power supply system abnormality.

  In order to achieve the above object, an image forming apparatus according to the present invention is supplied with a voltage from an apparatus main body, a door for opening the inside of the apparatus main body, and a commercial power source. A voltage output means for outputting a second voltage lower than the voltage; an image forming means for forming an image on a recording material supplied with the first voltage from the voltage output means; and the door being opened. In response, a switch that cuts off the first voltage supplied from the voltage output means to the image forming means, a detection means that is disposed on the door and detects a recording material, and from the voltage output means Control means to which a second voltage is supplied, the control means at a timing when the level of the first voltage between the switch and the image forming means is lower than a predetermined threshold. Within a predetermined period before and after When the detection result by the detection means changes, it is determined that the door is opened, and when the detection result by the detection means does not change, it is determined that the commercial power supply or the voltage output means is abnormal. It is characterized by doing.

  According to the present invention, it is possible to provide an image forming apparatus capable of quickly detecting whether the voltage level change on the rear stage side of the interlock switch is caused by door opening or power supply system abnormality.

Cross section of image forming apparatus Control block and power system diagram Diagram of loop sensor and door opening / closing Timing chart of conventional control when voltage drop of commercial power supply Detection timing chart of Example 1 Control flow chart of embodiment 1 Example of another embodiment of Example 1 Control flowchart of embodiment 2 Detection timing chart of Example 3

[Example 1]
A cross-sectional view of the image forming apparatus is shown in FIG. In this embodiment, an example of a laser beam printer is shown as the image forming apparatus. When receiving a print instruction from an external device such as a PC, the laser beam printer 100 (hereinafter referred to as the printer 100) rotates the photosensitive drums 101a, 101b, 101c, and 101d. The photosensitive drums 101a, 101b, 101c, and 101d are uniformly charged by the charging rollers 102a, 102b, 102c, and 102d, respectively. Thereafter, electrostatic latent images are formed on the surfaces of the photosensitive drums 101a, 101b, 101c, and 101d by laser light from the laser exposure apparatus 103. The electrostatic latent images formed on the photosensitive drums 101a, 101b, 101c, and 101d are attached with toner by the developing devices 104a, 104b, 104c, and 104d, and are visualized as toner images. Yellow, magenta, cyan, and black toner images are formed on the photosensitive drums 101a, 101b, 101c, and 101d, respectively.

  The intermediate transfer belt 105 (image carrier) is suspended by suspension members (a driving roller 106, a counter roller 107, a tension roller 108, and an auxiliary roller 109), and is substantially the same as the photosensitive drums 101a, 101b, 101c, and 101d. It is rotationally driven at a peripheral speed of. The visualized toner images are transferred to the intermediate transfer belt 105 by primary transfer rollers 110a, 110b, 110c, and 110d, respectively, in the process of passing through the contact portions between the photosensitive drums 101a, 101b, 101c, and 101d and the intermediate transfer belt 105. . At this time, a primary transfer bias is applied to the primary transfer rollers 110a, 110b, 110c, and 110d, respectively. The toner remaining on the surfaces of the photosensitive drums 101a, 101b, 101c, and 101d is removed by the cleaning devices 111a, 111b, 111c, and 111d. In this way, a plurality of color toner images are superimposed on the intermediate transfer belt 105, and a full-color image corresponding to the target color image is obtained.

  The sheet S (recording material) is selected and fed one by one by supplying a driving force from a sheet feeding motor 201 described later with reference to FIG. 2 when the pickup roller 112 drives a pickup solenoid (not shown). It is sent out to the conveyance path. The sheet S passes through the registration roller 113 and reaches the registration sensor 114. The sheet S is aligned with the full-color image on the intermediate transfer belt 105 by detecting the leading edge with the registration sensor 114 and adjusting the speed, and is conveyed to the secondary transfer unit. In the secondary transfer portion, the full color image on the intermediate transfer belt 105 is transferred onto the paper S by the secondary transfer bias applied to the secondary transfer roller 115 (transfer member). The sheet S carrying an unfixed full-color image is introduced into the fixing device 117 via the loop sensor 116, and is heated and pressed by a nip portion composed of a heating roller 118 and a pressure roller 119 (fixing member). It is fixed on the paper S. The fixed sheet S is discharged out of the apparatus by a discharge roller 121 via a discharge sensor 120. The toner remaining on the surface of the intermediate transfer belt 105 is removed by the transfer belt cleaning device 122.

  The door 123 is configured to be openable and closable so that the user can access the machine when the paper S is jammed. By opening the door 123, the inside of the printer main body 150 (also referred to as an apparatus main body or a casing) is opened.

  Next, the control unit of the printer 100 will be described with reference to FIG. In the figure, solid arrows indicate signal input / output, and dotted arrows indicate power supply. The main control device 200 is composed of, for example, a combination of CPU and ASIC, and controls the image forming operation. The main control device 200 drives the paper feed motor 201, the fixing motor 202, and the drum motor 203, and rotates the registration roller 113, the pressure roller 119, and the secondary transfer roller 115, each of which is a driving source, to convey the paper S. To do. The main controller 200 controls a charging current output unit, a developing current output unit, a primary transfer current output unit, and a secondary transfer current output unit 204 (not shown) to perform toner image formation and transfer control.

  The image controller 205 is connected to an external device such as a PC, for example, and converts the print image into video data using the image processing unit 206 and notifies the main controller 200 of it. Further, the main controller 200 displays the status of the printer 100 such as door opening / closing information determined by the door opening / closing determination unit 207 on the display unit 208 (also referred to as an operation panel) to notify the user. The power supply control unit 209 controls driving or stopping of the 24V generation unit 211 of the low-voltage power supply unit 210 (voltage output unit), and switches the power state of the printer 100. Further, the 24V output detection unit 212 monitors the generated voltage of the 24V generation unit 211.

  The 3.3V generation unit 213 supplies power to the main controller 200, the loop sensor 116, the registration sensor 114, the paper discharge sensor 120, and the image controller 205. The 24V generation unit 211 includes driving units such as a paper feed motor 201, a fixing motor 202, and a drum motor 203, a charging current output unit, a development current output unit, a primary transfer current output unit, and a secondary transfer current output unit 204 (not shown). Is supplying power. Since the secondary transfer roller 115 is exposed when the door 123 is opened, the power supply to the secondary transfer current output unit 204 (voltage application unit) is configured to be cut off by the interlock switch 214. The fact that the power supply is cut off by the interlock switch 214 is input to the main controller 200 as, for example, 1 when the voltage level is 20 V or higher and 0 when the voltage level is lower than 20 V as the input of the interlock post-stage voltage detection unit 215. The These pieces of information are used as one of detection means necessary for the determination by the door opening / closing determination unit 207.

  Next, the operation of the door opening when the door 123 is opened and closed and the commercial voltage drops in this configuration will be described with reference to FIG. FIG. 3A shows a state near the door opening when the door 123 is closed. The loop sensor 116 includes a photo interrupter 301 and a light shielding flag 302, and the photo interrupter 301 is arranged in a form attached to the fixing device 117. The light-shielding flag 302 is disposed on the door 123 and is stationary in such a manner that it projects on the conveyance path by its own weight. FIG. 3B shows a state near the door opening during the image forming operation. When the sheet S is conveyed by the secondary transfer roller 115 and reaches the pressure roller 119, and there is a speed difference between the pressure roller 119 and the secondary transfer roller 115, a loop is formed on the sheet S. When a loop is formed on the sheet S, the light blocking flag 302 is pushed up in contact with the sheet S. Then, the photo interrupter 301 detects light shielding and detects the presence of paper (ON state). Since the on / off of the loop sensor 116 is switched according to the loop amount of the paper S, the printer 100 keeps the loop amount of the paper S between transfer and fixing constant by adjusting the speed of the fixing motor 202 according to the change of the loop sensor 116. Can be kept in.

  FIG. 3C shows a state near the door opening when the door 123 is open. Since the secondary transfer roller 115 and the light blocking flag 302 of the loop sensor 116 are arranged on the door 123, they are separated from the conveyance path in conjunction with the door opening. When the door is opened from the state of FIG. 3A, the light blocking flag 302 always passes through the photo interrupter 301, so the logic of the loop sensor 116 changes from transmission to light blocking and transmission. That is, it is turned off → on → off. Even when the paper S pushes up the light blocking flag 302 as shown in FIG. 3B, the light always changes from light blocking to transmission. That is, it turns from on to off. Accordingly, a transient state of the door open can be detected based on a change from the light shielding to the transmission of the loop sensor 116 other than the timing at which the rear end passage of the paper S is predicted.

Furthermore, FIG. 4 demonstrates the voltage change of the latter stage of an interlock at the time of a commercial voltage drop, and conventional control. In the present embodiment, a case where the commercial power source drops from 120V to 40V will be described as an example. If the voltage level of the commercial power supply drops to a certain level while the printer 100 is performing image formation, the printer 100 can supply power to the 3.3V generation unit 213 without any problem, but the load on the 24V generation unit 211. Insufficient power can be supplied. Therefore, the 24V generation unit 211 stops the power supply. When the power supply is stopped, the 24V generator 211 is in a state of consuming the electric power stored in the capacitor or the like, so that the voltage level gradually decreases. When the voltage level of 24V generator 211 falls below the threshold value V _1, the main controller 200 detects the voltage drop of the interlock-stage. When it is determined that the change in the interlock post-stage voltage detection unit 215 is that the door is open, the printer 100 stops driving and high-voltage output that are loads. The display unit 208 notifies the door opening. Further, when the voltage level of 24V generator 211 falls below the threshold value V ₂ decreases, detects an abnormality of the power supply voltage is 24V output detection unit 212 notifies the power failure by using the display unit 208. However, the printer 100 notifies the user of an erroneous message during the time period T ₀ required for the voltage level of the 24V output detection unit 212 to change from the threshold value V ₁ to the threshold value V ₂ . Operation of the printer 100 stops the detection stages a door open false, since the main load 24V generator 211 is supplying power is stopped, the interval of time T ₀ is released the remaining charge in the standby Will be maintained for a long time.

  In this embodiment, by combining the loop sensor 116 and the interlock post-stage voltage detection unit 215, whether the voltage change detected by the interlock post-stage voltage detection unit 215 is due to a door open, the voltage of the commercial power supply or the 24V generation unit is abnormal. Judge quickly. The method will be described below.

FIG. 5A shows the relationship between the interlock post-stage voltage detection unit 215 and the loop sensor 116 when the door is opened. The 24V generator 211 has no voltage change. When the door 123 is physically opened, the light blocking flag 302 of the loop sensor 116 passes through the photo interrupter 301 during the period before and after the interlock post-stage voltage detection unit 215 is turned off. Therefore, the detection result of the loop sensor 116 is once turned on and immediately turned off. Main controller 200 determines the door opening at the timing when the change of loop sensor 116 from on to off is detected, and notifies the user of a door open message using display unit 208. Predetermined period of time T ₁ is the light shielding flag 302 on the door, allowed to store the value set in consideration of variations in the operating time required for the mechanical arrangement and the door opening of the body side of the photo-interrupter 301 in advance in the main control device 200 .

FIG. 5B shows the relationship between the interlock post-stage voltage detection unit 215 and the loop sensor 116 when the door is opened in a state where the paper S pushes up the light shielding flag 302 of the loop sensor 116 as shown in FIG. Is shown. Since the light shielding flag 302 is pushed up, the loop sensor 116 is kept on, but the sensor logic is turned off because the light shielding flag 302 is separated from the conveyance path by opening the door. Accordingly, the door open can be displayed on the display unit 208 by the same operation as in FIG. FIG. 5C shows a case where the change of the loop sensor 116 occurs before the voltage level drop of the interlock post-stage voltage detection unit 215 is detected. Main controller 200 stores the change time of loop sensor 116 from on to off in advance. When the post-interlock voltage detector 215 detects a decrease in the voltage level, if the last change from the ON state to the OFF state of the loop sensor 116 is within the period T ₁ , the door is opened on the display unit 208 at that time. Is notified.

FIG. 5D shows the relationship between the interlock post-stage voltage detection unit 215 and the loop sensor 116 when the commercial voltage drops. Since there is no physical operation of the door 123, there is no change in the input of the loop sensor 116. After a period T ₁ before and after the interlock post-stage voltage detection unit 215 is turned off from on, the display unit 208 changes the change of the interlock post-stage voltage detection unit 215 from on to off. It is determined that there is an abnormality and a power supply abnormality is notified.

  Next, a control flow for door opening / closing detection will be described with reference to FIG. Control based on the flowchart of FIG. 6 is executed by main controller 200 based on a program stored in a ROM or the like.

First, main controller 200 monitors a change in the logic of loop sensor 116 from on to off (step 601), and stores the last time (step 602). Thereafter, when a change in voltage level is detected by interlock post-stage voltage detection unit 215 (step 603), main controller 200 calculates start time T ₂ and end time T ₃ according to period T ₁ from the change point (step 603). Step 604). It is confirmed whether the change time from on to off of the loop sensor 116 which has been stored is the start time T ₂ later (step 605), the door opening and closing determination unit 207 at the time when the subsequent door opening Is determined (step 606). Later, the door opening and closing determination section 207 when detecting from ON to OFF of the loop sensor 116 until reaching the end time T ₃ to confirm the door open. When it reaches the end time _{T 3} without detecting the off-loop sensor 116 (step 607), the main control unit 200 notifies the power failure (step 608).

  In this way, it is possible to determine whether the door is open, the commercial power supply, or the 24V generator 211 is abnormal, based on the change in the interlock post-stage voltage detection unit 215 and the change in the loop sensor 116. As a result, it is possible to prevent erroneous notification of door opening and to promptly display a message on the display unit 208 even when an abnormality occurs in the commercial power supply or the 24V generation unit 211 to notify the user. Further, since a dedicated sensor specialized for detecting opening / closing of the door 123 is not provided, there is no cost increase.

  As described above, according to the present embodiment, it is possible to provide an image forming apparatus capable of quickly detecting whether the voltage level change on the rear stage side of the interlock switch is caused by door opening or power supply system abnormality.

[Example 2]
In the present embodiment, a door structure that is more suitable for performing the control of the first embodiment will be described. The basic configuration of the door 123 is the same as that shown in FIG. At this time, the position of the sensor is set so that the timing at which the detection result of the loop sensor 116 changes from on to off due to the door opening is always after the timing at which the detection result of the interlock post-stage voltage detection unit 215 changes from on to off. decide. The description of the main part is the same as that of the first embodiment, and only the parts different from the first embodiment will be described here.

  The control flow in the case of the said structure is demonstrated using FIG. The control based on the flowchart of FIG. 7 is executed by the main control device 200 based on a program stored in a ROM or the like.

First, when the interlock subsequent voltage detection unit 215 is changed from on to off (step 501), the main controller 200 calculates the end time _{T 3} (step 502), monitoring the change from ON to OFF of the loop sensor 116 Is started (step 503). When the change is detected, main controller 200 determines that the door is open, and notifies door open using display unit 208 (step 504). When it reaches the end time T ₃ without detecting a change in the loop sensor 116 (step 505), the main control unit 200 notifies the power failure by using the display unit 208 determines that the power failure (step 506).

By determining the positional relationship of the sensors in this way, the loop sensor 116 changes from ON to OFF before the interlock post-stage voltage detection unit 215 changes from ON to OFF due to the door opening as shown in FIG. 5C. Disappears. Therefore, since the start time T ₂ are a timing at which the interlock subsequent voltage detection unit 215 is changed from on to off, it is possible to perform the detection similar to simpler in Example 1.

[Example 3]
In the present embodiment, means for further improving the detection accuracy in performing the control of the first embodiment will be described with reference to FIG. As described above, the loop sensor 116 is turned on when the sheet S is conveyed by the pressure roller 119 and the secondary transfer roller 115 and the loop amount increases. Here, for example, when the pressure roller 119 expands and the passage becomes larger and the peripheral speed becomes faster, the loop sensor 116 is turned off.

When a voltage drop of the commercial power supply occurs, a change from ON to OFF of the interlock post-stage voltage detection unit 215 is detected before the loads of the fixing motor 202 and the drum motor 203 cannot be maintained, and the main control device 200 Instruct to stop. At this time, the motor is stopped so that the stop distance S ₁ on the pressure roller 119 of the fixing motor 202 is shorter than the stop distance S ₂ on the secondary transfer roller 115 of the drum motor 203.

In this way, control is performed so that the rear end side of the sheet S is pushed in and the logic of the loop sensor 116 is held in the ON state. This prevents the paper S from being pulled and the light-shielding flag 302 returns to the conveyance path side, preventing the loop sensor 116 from detecting the off state, and the accuracy of determining whether the door is open, the commercial power supply or the 24V generator 211 is abnormal. Can be increased. In order to make the stop distance S ₁ of the fixing motor 202 shorter than the stop distance S _{2 of the} drum motor 203, for example, a mechanical configuration in which the load applied to the driving unit of the fixing motor 202 becomes heavier than the torque applied to the driving of the drum motor 203. You may take. Further, for example, the fixing motor 202 may be stopped suddenly using a deceleration signal, and the drum motor 203 may be controlled to stop gently without outputting a deceleration signal or an acceleration signal.

  In the above embodiment, the laser beam printer 100 having the color inline configuration has been described as an example. However, as long as the loop sensor 116 is provided, a color 4-pass printer or a monochrome printer may be used. Furthermore, a printer of another printing method such as an ink jet printer or a copying machine may be used.

  In the above embodiment, the loop sensor 116 has been described as an example, but the present invention is not limited to this. For example, as shown in FIG. 9, an optical sensor 400 that detects the sheet S on the conveyance path may be used. The optical sensor 400 includes a light receiving unit 401, an irradiation unit 402, and a reflecting member 403.

  First, a state where the door 123 is closed will be described with reference to FIG. When the paper S is conveyed to the detection area of the optical sensor 400, the light emitted from the irradiation unit 402 is reflected by the surface of the paper S and received by the light receiving unit 401. This state is referred to as an on state. When the sheet S is not conveyed to the detection area, the light emitted from the irradiation unit 402 is not received by the light receiving unit 401. This state is referred to as an off state.

  Next, a state where the door 123 is opened will be described with reference to FIG. The light receiving unit 401 and the irradiation unit 402 are attached to the door 123, and the reflecting member 403 is attached to the fixing device 117. When the door 123 is opened, the retracted reflecting member 403 moves as shown in FIG. 9B and reflects the light emitted from the irradiation unit 402 toward the light receiving unit 401. Thereby, the detection result of the optical sensor 400 is turned on. When the door 123 is further opened, the light irradiated from the irradiation unit 402 does not hit the reflecting member 403, and the detection result of the optical sensor 400 is turned off.

  With the above configuration, the door opening / closing transient state can be detected not only by the loop sensor 116 but also by the optical sensor 400.

DESCRIPTION OF SYMBOLS 100 Laser beam printer 115 Secondary transfer roller 116 Loop sensor 123 Door 150 Printer main body 200 Main controller 204 Secondary transfer current output part 207 Door opening / closing judgment part 210 Low voltage power supply part 214 Interlock switch 215 Interlock post-stage voltage detection part 215

Claims (9)

The device body;
A door for opening the inside of the apparatus body;
Voltage output means for supplying a voltage from a commercial power source and outputting a first voltage and a second voltage lower than the first voltage;
The first voltage is supplied from the voltage output means, and an image forming means for forming an image on a recording material;
A switch for cutting off the first voltage supplied from the voltage output means to the image forming means in response to the opening of the door;
A detecting means disposed on the door for detecting the recording material;
Control means to which the second voltage is supplied from the voltage output means,
The control means changes the detection result by the detection means within a predetermined period before and after the timing when the level of the first voltage between the switch and the image forming means becomes lower than a predetermined threshold. In this case, it is determined that the door is opened, and if the detection result by the detection unit does not change, it is determined that the commercial power supply or the voltage output unit is abnormal. The image forming means includes a transfer member that transfers a toner image formed on an image carrier to a recording material, and a voltage application unit that applies a voltage to the transfer member.
The image forming apparatus according to claim 1, wherein the switch cuts off the first voltage supplied to the voltage application unit in response to the opening of the door. A fixing member for fixing the toner image transferred to the recording material to the recording material;
The detection means is a flag that moves in contact with the recording material conveyed by the transfer member and the fixing member, and is a flag of a loop sensor for detecting a loop amount of the recording material. The image forming apparatus according to claim 2. The loop sensor includes the flag and a photo interrupter that outputs a signal according to the position of the flag,
The image forming apparatus according to claim 3, wherein the flag is attached to the door, and the photo interrupter is attached to the fixing member.   When the loop amount of the recording material in contact with the flag is small, or the flag is not in contact with the recording material, the photo interrupter outputs a first signal, and the recording material in contact with the flag The image forming apparatus according to claim 4, wherein when the loop amount is large, the photo interrupter outputs a second signal different from the first signal.   6. The image according to claim 5, wherein when the door is opened, a signal output from the photo interrupter changes from the second signal to the first signal within the predetermined period. Forming equipment.   7. The predetermined period is set in advance according to a variation in a position where the loop sensor is attached and a time required for opening the door. 2. The image forming apparatus according to item 1. A first drive for rotating the transfer member;
A second drive unit for rotating the fixing member,
The switch does not cut off the first voltage supplied to the first drive unit and the second drive unit in response to the door being opened, and the level of the first voltage is 8. The control unit according to claim 3, wherein the control unit stops the first drive unit and the second drive unit at a timing lower than the predetermined threshold value. 9. Image forming apparatus. In the control unit, the distance that the recording material is conveyed by the transfer member is longer than the distance that the recording material is conveyed by the fixing member before the transfer member and the fixing member stop rotating. The image forming apparatus according to claim 8, wherein the first drive unit and the second drive unit are stopped as described above.

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