JPH01297667A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent trouble, damage and fire due to abnormal heating by stopping the drive of a fixing device and/or various devices required for performing the sequence for image formation in case a device main body is tilted. CONSTITUTION:The title device is provided with a tilting state detecting means, that is, an inclination sensor 15, outputting a prescribed detecting signal in case the device main body 100 is tilted. When the sequence for image formation is executed with the device main body 100 tilted, a fixing device control circuit 26 outputs a drive stopping instruction signal to a fixing device driving circuit 27 according to a signal at a logical level 'L' outputted from the sensor 15. As a result, power supply to a fixing heater 12c is stopped. Therefore, the damage or fire, which is caused by the propagation of heat from the fixing device 12 to the image forming device or other parts that are not insulating, can be prevented.

Description

[Detailed description of the invention] LLIαlL circle! The present invention relates generally to image forming apparatuses, and more particularly to image forming apparatuses such as electrophotographic copying machines and laser beam printers.

As is well known, this type of image forming apparatus is internally equipped with an image forming section, a transfer material conveyance system, a fixing device, etc., and the visible image formed by the image forming section is The 0 image forming section is configured to transfer images onto a transfer material conveyed by a transfer material conveyance system, and to fix the transferred visible image on the transfer material in a fixing unit 911.
It performs the steps of charging, image exposure, development, and transfer.
In addition to the rotatably supported photoreceptor drum as an image carrier, primary charging means, image exposure means, development means, transfer charging means, which are arranged so as to surround the outer peripheral surface of the photoreceptor drum, Equipped with cleaning means etc. The transfer material conveyance system supplies the transfer material contained in the paper feed tray one by one from a paper feed tray configured to be detachably attached to the main body of the image forming apparatus to the image forming section. It is designed to convey the transfer material that has passed through to the fixing device, and is equipped with a paper feed roller, a transfer material guide, a registration roller, a transfer material guide, etc. from the upstream side to the downstream side in the transfer material conveyance direction. are doing. When the fixing device receives a transfer material onto which a visible image corresponding to the original image information has been transferred through the steps of charging, image exposure, development, and transfer executed in an image forming section, the transfer material conveyance system conveys the transfer material. This transfer material is received by a roller pair consisting of a fixing roller and a pressure roller, and is heated and pressed to fix the image. In addition to the above-mentioned fixing roller and pressure roller, the fixing device also includes a fixing heater installed on a rotating shaft that rotatably supports the fixing roller, and a thermistor that detects the temperature of the outer circumferential surface of the fixing roller and pressure roller. , a drive power source that supplies power to the fixing heater, and a drive power source that reads a detection signal output from a thermistor and drives the fixing heater in order to adjust the temperature of the outer peripheral surface to the temperature necessary for image fixing at all times during the image forming sequence. It has a control system etc. to control it.

By the way, in the fixing device configured as described above,
The temperature of the outer peripheral surface of the fixing roller and pressure roller is normally 200℃.
Since it is heated by a fixing heater or the like to a fairly high temperature of approximately .degree. C., the ambient temperature near the fixing device also becomes quite high. Therefore, in conventional image forming apparatuses, a shielding mechanism made of a heat insulating material or the like is installed in the fixing device as a protection measure for heat-sensitive equipment such as various circuit components and optical components disposed around the fixing device. A heat exhaust fan or the like may be provided between the image forming apparatus and the equipment to prevent heat from the fixing device from being conducted to the equipment, or to prevent an increase in ambient temperature within the image forming apparatus. , a method has been adopted in which the atmosphere around the fixing device is cooled by generating convection above the fixing device using the heat exhaust fan or the like.

However, if the installation location of the image forming apparatus is extremely tilted, or if a service person operates the image forming apparatus with the main body lying on its side during maintenance, this may cause the image forming apparatus's heat dissipation design to change. Alternatively, there is a risk that parts of the image forming apparatus that are not designed for heat dissipation or heat insulation may be heated, and the heated parts may be damaged. There was a possibility that this problem would occur. Furthermore, some image forming apparatus models are set to a mode that forcibly stops only the drive of the fixing device and operates the image forming unit and other equipment only during maintenance. However, if a service person does not cancel the mode setting while performing maintenance on such an image forming apparatus with the apparatus body lying on its side, the image forming apparatus may There was also the problem that the forming device did not operate normally.

Therefore, the present invention has been devised to solve the above-mentioned problems, and its purpose is to prevent the fixing device and/or image forming device from moving when the main body of the image forming apparatus is placed in an inclined state. By stopping the drive of each device necessary to execute the sequence, parts of the various devices that make up the image forming apparatus that are not designed for heat dissipation or insulation are abnormally unheated. An object of the present invention is to provide an image forming apparatus that does not cause malfunctions such as failure, damage, or fire.

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides a driving means for driving each device necessary to execute a process of forming a visible image corresponding to image information, and a transfer material to which a visible image formed through the process is transferred. and a fixing device that fixes the visible image on the transfer material in a tilted state in which the image forming apparatus outputs a predetermined detection signal when the main body of the image forming apparatus is placed in a tilted state. The image forming apparatus is characterized in that it includes a detection means and a control means for stopping the drive of the drive means and/or the fixing device when a predetermined detection signal is output from the tilt state detection means.

Branch l Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of an image forming apparatus according to a first embodiment of the present invention.The outline of the image forming apparatus according to a first embodiment of the present invention is as described below. It is. That is, in FIG. 1, the main body of the image forming apparatus (
(hereinafter simply referred to as the "device main body") Zoo's 1st v! At the bottom of the right side of J.

A paper feed tray 1 is removably attached to the apparatus main body 100, and a transfer material discharge port 16 is formed approximately in the center of the left end of the apparatus main body 100 in FIG. In a region near the transfer material discharge port 16 in the apparatus main body 100, a space is set that is partitioned from other regions by a shielding member 17 made of a heat insulating material or the like and formed to have an abbreviated cross-section. ing. In this space, a fixing member 111112, a pair of paper discharge rollers 13, and a paper discharge sensor 14 are provided. A transfer material transport system 18 is provided below the area from the downstream end of the paper feed tray 1 in the transfer material transport direction to the entrance of the fixing device 12 in the apparatus main body 100 . An image forming section 19 is provided in the space. The above configuration will be further explained as follows. That is, the fixing device 12 includes a fixing roller 12a.
, a pressure roller 12b provided in contact with the outer circumferential surface of the fixing roller 12a, a fixing heater 12C provided in a shaft rotatably supporting the fixing roller 12a, and a visible image formed in the image forming unit 19. a transfer material guide member 12d that receives the transferred transfer material and guides it to a portion where the outer peripheral surface of the fixing roller 12a and the outer peripheral surface of the pressure roller 12b are in contact;
It consists of a thermistor (not shown), etc. that detects the temperature of the outer peripheral surfaces of the fixing roller 12a and the pressure roller 12b.

The fixing roller 12a and the pressure roller 12b are configured to receive the transfer material onto which the visible image has been transferred in the image forming section 19, and fix the visible image by heating and pressurizing the transfer material. The paper ejection roller pair 13 is a fixing roller 12a.
The transfer material on which the image has been fixed is received by the pressure roller 12b and is discharged to the outside of the apparatus main body 100 via the transfer material discharge port 16. The paper discharge sensor 14 detects whether or not the transfer material is properly discharged to the outside of the apparatus main body 100 by the paper discharge roller pair 13 and outputs a predetermined electrical signal. Details of the configuration of the paper discharge sensor 14 will be described later. The transfer material conveyance system 18 includes a paper feed roller 2 disposed close to the downstream end of the paper feed tray 1 in the transfer material conveyance direction.

A transfer material guide 20 that receives and guides the transfer material supplied by the paper feed roller 2, a pair of registration rollers 3 that receives the transfer material guided by the transfer material guide 20 and sends it out at a predetermined timing, and a pair of registration rollers. a transfer material guide 21 that receives the transfer material sent out by the transfer material 3 and guides it to the image forming section 19;

A transfer material feed roller 22 that sends out the transfer material on which the visible image has been transferred in the image forming section 19, and a transfer material guide 23 that guides the transfer material sent out from the transfer material feed roller 22 to the fixing VC station 12. The image forming section 19 includes an optical unit 24 provided in an area from the upper left to the center of the apparatus main body 100, and
a photoreceptor drum 8 provided near the center of the interior, a pre-exposure lamp 7 provided along the outer peripheral surface of the photoreceptor drum 8 around the photoreceptor drum 8; Developing device 9, transfer charging device ll, and cleaning device 2
5. The photosensitive drum 8 is rotatably supported clockwise in FIG. The pre-exposure lamp 7 exposes the outer peripheral surface of the photoreceptor drum 8 to zero the electric charge remaining on the outer peripheral surface of the photoreceptor drum 8.

The charger 10 is configured to charge the outer peripheral surface of the photosensitive drum 8, which has been neutralized by the pre-exposure lamp 7, approximately uniformly. The optical unit 24 includes a semiconductor laser 5. It consists of a polygon mirror 4, a folding mirror 6, etc.
By scanning the outer peripheral surface of the photosensitive drum 8 from a gap defined by the primary charger 10 and the developing device 9 with a laser beam modulated in accordance with document image information, the drum 8 is
An electrostatic latent image is formed on the outer peripheral surface of the. The developing device 9 is disposed on the downstream side in the rotational direction of the photoreceptor drum 8 with respect to the primary charger IO via the above-mentioned gap. The developing device 9 has a developing roller 9a, and when a developing bias is supplied to the developing roller 9a from a developing bias power source (not shown), the developer stored in the developing device 9 is exposed to the photosensitive material. The electrostatic latent image formed on the body drum 8 is made into a visible image. Transfer charger 1
1 is disposed on the downstream side in the rotational direction of the photoreceptor drum 8 with respect to the developing device 9, and is used to transfer a visible image formed on the outer peripheral surface of the photoreceptor drum 8 via a transfer material guide 21. The image is configured to be transferred to a material. The cleaning device 25 is disposed upstream of the pre-exposure lamp 7 in the rotational direction of the photoreceptor drum 8, and scrapes and collects residual toner on the outer peripheral surface of the photoreceptor drum 8. In addition,
The image forming sequence executed by the image forming apparatus having the above-mentioned configuration is already well known, so a description thereof will be omitted.

Furthermore, according to the first embodiment of the present invention, in the upper right side of the apparatus main body 100 in FIG. That is, the tilt sensor 15 according to the first embodiment of the present invention, in which the tilt sensor 15 is provided, has one end rotatably supported by the device main body 100 at a fulcrum A, as shown in FIG. There is also a conductive shaft 15a to which a weight 15c is attached to the other end, and a device body 10 which is attached around the conductive shaft 15a.
The conductive ring 15b is set so that the conductive shirt 15a is located approximately at the center point when the conductive ring 15a is placed in a substantially horizontal state. As is clear from FIG. 3, the conductive shaft 15a is connected to the power supply Vcc via a resistor 28.
On the other hand, the conductive ring 15b is grounded. The tilt sensor 15 performs a so-called pendulum operation depending on the installation state of the device main body 100.

FIG. 3 shows a fixing device control system included in an image forming apparatus according to a first embodiment of the present invention. A fixing device control system according to this embodiment is illustrated in FIG. The image forming apparatus is comprised of a tilt sensor 15, control means, that is, a fixing device control circuit 26, a fixing device drive circuit 27, and a fixing heater 12c. The fixing device control circuit 26 is connected to the device main body lO.
When the conductive shirt 15a and the conductive ring 15b are kept in a non-contact state due to the fact that the conductive ring 15a is placed in a substantially horizontal state, the resistor 28 is connected to the power supply voltage Vcc output from the tilt sensor 15. A voltage signal (that is, logic level "H") from which the voltage drop caused by the voltage drop is subtracted is input. The fixing device control circuit 26 detects the output from the tilt sensor 15 when the conductive shirt 15a and the conductive ring 15b are in contact with each other because the device main body 100 is placed in a tilted state. voltage signal (Ov,
That is, the logic level "H") is input. The fixing device control circuit 26 receives the logic level " from the tilt sensor 15.
When a signal of "H" is output, it is recognized that the main body 100 of the apparatus is placed in a substantially horizontal state, and a drive command signal is output to the fixing device drive circuit 27, and a logic level "L" is output from the tilt sensor 15. When the signal is output, it is configured to recognize that the apparatus main body 100 is placed in a tilted state and output a drive stop command signal for the fixing device 2 to the drive circuit 27.Fixing device drive circuit 27 In accordance with a command signal output from the fixing device control circuit 26, the power supply to the fixing heater 12c from a fixing heater drive power source (not shown) is cut off/maintained.

In the above-described configuration, even if an attempt is made to execute the image forming sequence while the main body 100 is tilted, the fixing device control circuit 26 is activated by the logic level "L" signal output from the tilt sensor 15. outputs a drive stop command signal to the fixing device drive circuit 27, so power supply to the fixing heater 12c is cut off. Therefore, the fixing device 12 is not placed in a driving state, and the heat from the fixing device 12 is transmitted to parts of the image forming apparatus that are not designed for heat dissipation or heat insulation, which may cause damage to the parts or a fire. It is now possible to prevent such problems from occurring. In this embodiment, when the tilt sensor 15 detects that the apparatus main body 100 is placed in a tilted state, the driving of the fixing device 12 is stopped. 19 etc. may be stopped.

As is clear from the content explained above, in the first embodiment according to the present invention, the tilt sensor 15 is newly added as a means for detecting the tilt state of the device main body 100, but the number of parts is small. In order to reduce the cost of the image forming apparatus by reducing the tilt sensor 15,
A configuration may be considered in which the inclination state of the apparatus main body lOO is detected using the paper discharge sensor 14 shown in FIG.

FIG. 4 shows a more detailed structure of the paper discharge sensor 14 shown in FIG. 1. The paper discharge sensor 14 included in the image forming apparatus according to the present invention is rotatable. A weight 14c supported by the weight 14c, a substantially U-shaped photosensor 14a disposed near the weight 14c, and a weight 14c.
A flag 14b is attached to the weight 14C and is configured to rotate according to the rotation of the weight 14c so as to be able to appear and disappear into the space defined by the photosensor 14a. The weight 14c is caused by the transfer material discharged in the direction of the arrow in Fig. 4.
The bar 14d is configured to rotate the bar 14d.

The photosensor 14a includes a light emitting element such as I, ED, and a light receiving element such as a phototransistor, which are arranged facing each other at a predetermined distance.

The flag 14b is moved out of the space defined by the photosensor 14a by the transfer material discharged via the paper discharge roller pair 13 as shown in FIG. When the light reaches the light receiving element, a signal of logic level "H" is output.

The photosensor 14a has a logic level "L" when the flag 14b remains in the space and blocks the light emitted from the light emitting element from reaching the light receiving element.
” is configured to output a signal.

The paper ejection sensor 14 having the above-mentioned configuration is configured so that the transfer material passes through the paper ejection roller pair 13 to the main body 1 of the apparatus while the image forming apparatus is performing an image forming sequence in which images are continuously copied.
00, a logic level "H" signal with a time width t1 is output at predetermined intervals as shown in the north part of FIG. That is, when image copying is performed continuously, the transfer material discharged via the paper discharge roller pair 13 comes into contact with the bar 14d at predetermined time intervals, so that the transfer material is only in contact with the bar 14d while the transfer material is in contact with the bar 14d. Since the light emitted from the light emitting element reaches the light receiving element, the output signal from the paper discharge sensor 14 repeats on/off at predetermined time intervals. on the other hand.

If the transfer material to be ejected via the paper ejection roller pair 13 is not ejected out of the apparatus main body 100 for some reason and a jam occurs, the transfer material remains in contact with the bar 14d. Therefore, the paper discharge sensor 14 comes to continuously output a signal of logic level "H" as shown in the lower part of FIG. When a signal as shown in the lower part of FIG. 6 is output from the paper ejection sensor 14, the controller (not shown) that controls the driving of the entire image forming apparatus determines that a jam has occurred. Image forming section 1
The driving of the driver yt (not shown) that drives the fixing heater 12c and the fixing heater 12c are stopped.

By the way, the weight 14c forming the paper ejection sensor 14 having the above-described structure is used not only to eject the transfer material but also to eject the apparatus main body 1.
00 is also rotated when placed in a tilted state, and thereby the blocking of light emitted from the light emitting element toward the light receiving element by the flag 14b is released (see Fig. 5 (b)).
Therefore, in the image forming apparatus according to the second embodiment of the present invention, the inclination sensor 15 is not provided, and when one image forming apparatus is not performing an image forming sequence, the paper ejection sensor 14 is activated. When a level “H” signal is continuously output as shown in the lower part of Figure 6,
The controller drives the image forming section 19 and the like when the apparatus main body 100 is in a tilted state, and the fixing device 12
It was decided that the drive of the engine would be stopped.

Next, the control operation of the image forming apparatus according to the second embodiment of the present invention will be explained mainly with reference to the flowchart shown in FIG.

The controller determines whether or not the image forming apparatus is performing an image forming sequence, and when determining that the image forming sequence is not being performed (step 301), the process proceeds to step 303. If it is recognized in step 303 that the signal shown in the lower part of FIG. 6 is not output from the paper discharge sensor 14, the process returns to step 303. When it is recognized in step 303 that a signal as shown in the lower part of FIG. 6 has been output from the paper ejection sensor 14, a stop command signal is immediately output to the first stage of the driver that drives the image forming section 19, etc. and the fixing device 12, Until the output of the above-mentioned signal from the paper ejection sensor 14 is interrupted, the driving of each of the means and the fixing device 12, etc. is maintained in the stopped state (step 305). In step 301,
If it is determined that the image formation sequence is being executed,
Move to step 307, and step 307 to step 3
The normal jam detection operation up to step 09 is executed.

As is clear from the above explanation, in this embodiment, it is possible to detect the tilted state of the apparatus main body lOO using only the existing configuration without adding the tilt sensor 15 shown in the first embodiment. Ta.

In each embodiment according to the present invention, it is also possible to display on the display section of the image forming apparatus whether or not the apparatus main body 100 is tilted.

As explained above, according to the present invention, when the main body of the image forming apparatus is placed in a tilted state, the fixing device and/or various devices necessary for carrying out the image forming sequence are fixed. By stopping the drive, parts of the various devices that make up the image forming apparatus that are not designed for heat dissipation or insulation may become abnormally heated, resulting in malfunction, damage, or fire. Accordingly, it is possible to provide an image forming apparatus that does not cause such problems.

[Brief explanation of the drawing]

11th! ! ! + is an overall vertical cross-sectional view showing an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a tilt sensor included in the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a block diagram showing a fixing device control system included in the image forming apparatus according to the first embodiment of the present invention. FIG. 4 is a perspective view showing a paper ejection sensor provided in a fixing device included in an image forming apparatus according to the present invention. 5(a) and 5(b) are explanatory views of the mechanical operation of the paper discharge sensor shown in FIG. 4. FIG. FIG. 6 is a timing chart showing the transfer material detection operation of the paper discharge sensor illustrated in FIGS. 4, 5 (a), and (b). FIG. 7 shows a control system of an image forming apparatus in which the paper ejection sensor shown in FIGS. 4 to 5 (b) according to the second embodiment of the present invention also serves as a tilt state detection means. It is a flow chart showing control operation. 12: Fixing device 12c: Fixing heater 14: Paper discharge sensor 15: Tilt sensor 18: Transfer material conveyance system 19: Image forming section 26: Fixing device control circuit 27: Fixing device drive circuit %L/ ('J NT Figure 4 Figure 5 (a) Figure 5 (b) Figure 7

Claims (1)

[Claims] 1) A driving means for driving each device necessary to execute the process of forming a visible image corresponding to the image information, and a drive unit for receiving the transfer material onto which the visible image formed through the above process has been transferred, and the visible image is transferred to the transfer material. In the image forming apparatus, the image forming apparatus includes a fixing device for fixing an image on the transfer material, further comprising a tilt state detection means for outputting a predetermined detection signal when the main body of the image forming apparatus is placed in a tilted state. An image forming apparatus comprising: a control means for stopping driving of the drive means and/or the fixing device when a predetermined detection signal is output from the tilt state detection means.