JPH04276768A - Control method for image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a situation that the actions of an image forming device are interrupted in a state where 2 recording paper is left in a fixing means at the time of detecting the abnormality of the device by a device abnormality detecting means in such an image forming device that image- forming is executed by forming the unfixed image of intended image information on a recording paper fed from a paper feeding means by an image forming means and fixing the unfixed image by the fixing means. CONSTITUTION:This device is provided with the device abnormality detecting means 55 which detects the abnormality of the image forming device and a means for detecting a paper in a fixing part 53 which detects whether or not the recording paper exists in the fixing means. When the means 55 detects the abnormality of the device, succeeding paper-feeding from the paper feeding means is stopped, and when the means 53 detects the existence of the paper, the actions of the device are continued until the recording paper existing in the fixing means is continuously carried and passes the fixing means after fixing processing. After the recording paper passes the fixing means, the actions of the device are interrupted and the occurrence of the abnormality of the device is displayed on a display means 56.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention allows an image forming means to form an unfixed image of desired image information on recording paper fed from a paper feeding means, and fixes the unfixed image using a fixing means to form an image. The present invention relates to a method of controlling an image forming apparatus that performs formation.

0002

[Prior art] For example, electrophotographic copying machines, electrostatic recording devices,
A magnetic recording device, etc. uses an appropriate image forming process means such as electrophotography, electrostatic recording, magnetic recording, etc. on recording paper (transfer material sheet, electrofax sheet, electrostatic recording sheet, etc.) fed from a paper feeding means. An unfixed image, such as a toner image, corresponding to the image information of This is what executes the formation.

Conventionally, in this type of apparatus, when an abnormality detecting means detects that an abnormality that interferes with image formation has occurred during the operation of the apparatus, all apparatus operations up to that point are immediately stopped. Interrupting the sequence and activating the display means to make the operator aware of the occurrence of an abnormality,
We will encourage you to take the necessary measures.

0004

[Problem to be Solved by the Invention] However, in the case of a system in which the device operation sequence is immediately interrupted as soon as an abnormality is detected, if the recording paper is in the middle of passing through the fixing means at the time of the interruption, the This creates a situation in which the recording paper remains stuck between the fixing portions of the fixing means.

[0005] The fixing means is a fixing device of the film heating type proposed in Japanese Patent Application Laid-Open No. 63-313182 etc., that is, the film is brought into close contact with a heating body and slidably moved, and the surface of the film opposite to the heating body is If the fixing device is a fixing device that presses the recording material into close contact with the film and moves it past the heating body position and applies thermal energy from the heating body to the recording material through the film, the film may be damaged by contact with fingers, nails, etc. Since the device is configured so that fingers cannot directly touch the film to prevent the film from being damaged, it is not possible to remove the recording paper that is caught between the fixing portions of the fixing device and is in a stopped conveyance state. If you try to remove it by force, you may damage the film.
The developing material (toner) of the unfixed image portion of the recording paper remains on the film of the fixing section, which causes offset and the like.

[0006] Even when the fixing means is a pair of heat rollers and a pressure roller, or a pair of pressure rollers, it is difficult to remove the recording paper that is caught between the pair of rollers and stopped conveying, resulting in the same problem. There is. Further, in the case of a heat fixing means having a large heat capacity, the recording paper left on the fixing means may be burnt due to residual heat.

An object of the present invention is to eliminate the above-mentioned problems by devising a control sequence for interrupting the operation of the image forming apparatus when an abnormality occurs in the image forming apparatus.

[0008]

SUMMARY OF THE INVENTION The present invention is a method for controlling an image forming apparatus, which is characterized by the following configuration.

(1) Forming an unfixed image of desired image information on recording paper fed from a paper feeding means by an image forming means;
In an image forming apparatus that performs image formation by fixing the unfixed image with a fixing means, a device abnormality detection means detects an abnormality in the image forming apparatus, and detects whether recording paper is present in the fixing means. A fixing section paper detecting means is provided, and if an abnormality in the apparatus is detected based on the above-mentioned apparatus abnormality detecting means, the subsequent paper feeding from the paper feeding means is stopped, and the paper is transferred to the fixing section based on the above-mentioned fixing section paper detecting means. When the presence of paper is detected, a signal from the fixing section paper detecting means indicates that there is no paper, and after a period of time has elapsed until the recording paper has at least passed through the fixing section, the device drive and fixing operation are stopped, and the display section is displayed. A method for controlling an image forming apparatus, characterized by displaying an occurrence of an abnormality in the apparatus.

(2) The fixing means heat-fixes the image using a fixedly supported heating body and a pressure member that presses against the heating body and brings the recording paper into close contact with the heating body through a film. The method for controlling an image forming apparatus according to (1), characterized in that:

[0011]

[Operation] That is, the control means is controlled so that when an abnormality in the apparatus is detected, it is determined whether there is recording paper in the fixing means or not, and it is immediately determined whether or not to stop the apparatus drive and fixing operation. It is something. Even when the device abnormality detection means detects a device abnormality, if the fixing unit paper detection means detects that recording paper is present in the fixing means, the recording paper continues to undergo the fixing process. The operation of the apparatus is not interrupted until the paper has been conveyed and has passed through the fixing means, and if the operation of the apparatus is interrupted after the paper has passed, a situation may arise where the operation of the apparatus is interrupted while the recording paper remains in the fixing means. This eliminates the above-mentioned conventional problems caused by such a situation.

0012

Embodiments (1) Example of an image forming apparatus (FIG. 1) FIG. 1 shows a schematic configuration of an example of an image forming apparatus to which the control method of the present invention is applied. The image forming apparatus of this example is an electrophotographic copying apparatus of a reciprocating document table type, a rotating drum type, and a transfer type.

Reference numeral 100 denotes a device housing, and 1 denotes a reciprocating document mounting table made of a transparent plate member such as a glass plate disposed on the top plate 100a of the device housing.
The upper part is driven to reciprocate at a predetermined speed in the right direction a and the left direction a' in the drawing, respectively.

G is a document, which is placed on the top surface of the document table 1 according to a predetermined placement standard with the image side to be copied facing downward, and is pressed by placing the document pressure bonding plate 1a over it. Set.

Reference numeral 100b denotes a slit opening, which serves as a document illumination section, and is opened on the surface of the top plate 100a of the machine casing, with its length extending in a direction perpendicular to the direction of reciprocating movement of the document table 1 (direction perpendicular to the plane of the paper). The downward image surface of the document G set on the document platform 1 passes through the position of the slit opening 100b sequentially from the right side to the left side during the forward movement of the document platform 1 to the right side a. In the process of passing, the light L from the lamp 3 is received through the slit opening 100b and the transparent original table 1, and the document is illuminated and scanned. The light reflected from the document surface of the illumination scanning light is image-formed and exposed on the surface of the photosensitive drum 4 by the short focus and small diameter imaging element array 2.

The photosensitive drum 4 is coated with a photosensitive layer such as, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer.
It is driven to rotate in the clockwise direction of arrow b at a predetermined circumferential speed around a, and in the rotation process is uniformly charged with positive or negative polarity by the charger 5, and the uniformly charged surface is charged with the above-mentioned material. By receiving image-forming exposure (slit exposure) of the original image, electrostatic latent images corresponding to the image-forming exposed original image are successively formed on the surface of the photosensitive drum 4.

This electrostatic latent image is sequentially visualized by a developing device 6 using toner made of a resin or the like that softens and melts when heated.
The developed toner image moves to a location where a transfer discharger 9 is provided as a transfer section.

Reference numeral S denotes a cassette in which transfer material sheets P as recording paper are stacked and stored, and the sheets in the cassette are fed one by one by the rotation of the feed roller 7, and then transferred to the drum 4 by the registration roller 8. When the leading edge of the upper toner image forming section reaches the transfer discharger 9, the leading edge of the transfer material sheet P also reaches the position between the transfer discharger 9 and the photosensitive drum 4, and the timing is correct so that they coincide. and fed synchronously. Then, the toner image on the photosensitive drum 4 side is sequentially transferred onto the surface of the fed sheet by the transfer discharger 9.

The sheet to which the toner image has been transferred in the transfer section is sequentially separated from the four surfaces of the photosensitive drum by a separating means (not shown), and guided by a conveying device 10 to a fixing device 11, which will be explained next, where it is carried as an unfixed sheet. The toner image Ta is subjected to heat fixing processing and is discharged as an image-formed product (copy) onto a paper discharge tray 37 outside the machine through a guide 25 and a discharge roller 36.

On the other hand, the surface of the photosensitive drum 4 after the toner image has been transferred is subjected to removal of adhered contaminants such as residual toner by a cleaning device 20, and is used repeatedly for image formation. (2) Fixing device 11 (FIGS. 2 and 3) FIG. 2 shows the fixing device 11 used in the image forming apparatus shown in FIG.
The schematic configuration of the system is shown. This fixing device 11 is a film heating type fixing device.

Reference numeral 16 denotes an endless belt-shaped fixing film, which serves as a heating element fixedly supported below a driving roller 17 on the left side in the drawing, a driven roller 18 on the right side, and both rollers 17 and 18. Low heat capacity linear heating element 1
2, and a guide roller 1 disposed below the drive roller 17.
7a, the four members 17, 18, 12, 1 parallel to each other
It is suspended between 7a and 7a.

The driven roller 18 also serves as a tension roller for the endless belt-shaped fixing film 16.
The fixing film 16 is rotated clockwise at a predetermined circumferential speed as the drive roller 17 rotates clockwise, that is, the unfixed toner image Ta that is conveyed from the image forming section (transfer section 9 in FIG. 1) is supported on the upper surface. The transfer material sheet P is rotated at the same peripheral speed as the conveyance speed of the transfer material sheet P without wrinkling, meandering, or speed delay.

Reference numeral 19 denotes a pressure roller having a rubber elastic layer with good mold releasability, such as silicone rubber, as a pressure member;
The downward film portion of the endless belt-shaped fixing film 16 is sandwiched and pressed against the lower surface of the heating member 12 with a total contact pressure of, for example, 4 to 7 kg by means of an urging means, and the transfer material sheet It rotates forward and counterclockwise in the transport direction of P.

The rotatably driven endless belt-shaped fixing film 16 is repeatedly used to heat and fix toner images, so it has excellent heat resistance, releasability, and durability, and generally has a total thickness of 100 μm or less. Preferably, one with a thin wall of 40 μm or less is used.

For example, polyimide, polyetherimide,
A single-layer film of a heat-resistant resin such as PES/PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin), or a composite layer film, such as a 20 μm thick heat-resistant film, is coated with PTFE (40 μm) at least on the image contact side.
For example, a releasable coating layer made of a fluororesin such as fluorinated ethylene resin (fluorinated ethylene resin) or PAF with a conductive material added thereto is applied to a thickness of 10 μm.

The heating element 12 is a horizontally elongated member whose length is in the transverse direction of the fixing film (perpendicular to the running direction of the fixing film 16), and is held by a heater support 24 having high heat resistance, heat insulation, and insulation properties. The support body 24 is fixedly attached to a stay 23 as a stationary member of the fixing device 11 with the heating body holding side facing downward.

The heater support 24 holds the heating element 12 insulated and is made of highly heat-resistant material such as PPS (polyphenylene sulfide), PAI (polyamideimide), PI (polyimide), PEEK (polyetheretherketone), liquid crystal polymer, etc. It can be made of synthetic resins or composite materials of these resins and ceramics, metals, glass, etc.

The heating element 12 in this example has a heat-resistant, insulating, and low heat capacity heater substrate 13, a heating element 14 provided on the side of the substrate 13 facing the film 16, and a heating element 14 provided on the opposite side. It is a member having a low heat capacity as a whole, consisting of a temperature measuring element 15 and a surface protective layer 22 made of a glass material or the like which is provided to entirely cover the surface of the heater substrate on the side where the heating element 14 is provided.

The heater substrate 13 has a thickness of 1 mm, for example.
It is an alumina substrate with a width of 10 mm and a length of 240 mm. The heating element 14 is, for example, in the form of a line or band formed by coating (by screen printing, etc.) an electrically resistive material such as Ta2N, silver palladium, etc. to a width of 1 mm along the length of the lower surface of the substrate 13 approximately in the center. It is a current-carrying heating element with low heat capacity. The temperature measuring element 15 is, for example, a low heat capacity temperature measuring resistor such as a Pt film or a thermistor provided by coating (by screen printing or the like) along the length of the upper surface of the substrate 13 approximately at the center thereof.

In the case of this example, electricity is applied to the linear or band-shaped heating element 14 of the heating element 12 from both longitudinal ends thereof, causing the heating element 14 to generate heat over its entire length. In this example, the energization is a pulse-like waveform of DC 100V with a period of 20 msec, and the energization control circuit is configured to give a pulse according to the desired temperature and energy release amount controlled by the temperature detection element 15 by changing the pulse width. be. The pulse width is approximately 0.5 to 5 msec.

The image forming apparatus performs image forming operation in response to the image forming start signal, and the transfer material sheet P carrying the unfixed toner image Ta on its upper surface is conveyed from the transfer section (9) side to the fixing device 11 on the guide 21. The unfixed toner image surface enters between the fixing film 16 and the pressure roller 19 at the pressure contact portion N (fixing nip portion) between the heating body 12 and the pressure roller 19, and the unfixed toner image surface reaches the conveyance speed of the sheet P. The fixing nip between the heating body 12 and the pressure roller 19 is in close contact with the lower surface of the fixing film 16, which is moving in the same direction at the same speed as the fixing film 16, and is overlapped with the fixing film 16 without causing surface misalignment or wrinkles. It passes through part N while being subjected to a clamping force.

The toner image bearing surface of the sheet P receives heat from the heating element 14 via the fixing film 16 while passing through the fixing nip N while being in close contact with the fixing film surface.
The toner image melts at high temperature and becomes soft and adhesive Tb on the sheet P surface.
do.

In the case of the apparatus of this embodiment, the sheet P and the fixing film 16 are separated from each other when the sheet P passes through the fixing nip N and comes out. While the sheet P separated from the fixing film 16 is guided by a guide 25 and reaches the paper discharge section, the temperature of the toner Tb, which is higher than the glass transition point, naturally decreases (
(natural cooling) until the temperature reaches below the glass transition point and solidifies T.
At step c, the sheet P on which the image has been fixed is output.

The fixing film 16 is not limited to the shape of an endless belt, but as shown in the example shown in FIG. It may be configured such that it passes under the guide roller 17a and is locked to the take-up shaft 41, so that it travels from the feed-out shaft 40 side to the take-up shaft 41 side at the same speed as the conveyance speed of the transfer material sheet P.

(3) Apparatus operation interruption control FIG. 4 is a block diagram of the apparatus operation interruption control system when the abnormality detection means detects that some abnormality has occurred in the image forming apparatus, and FIG. 5 is a block diagram of the apparatus operation interruption control system. This is a general flowchart.

In FIG. 4, reference numeral 50 denotes a control means, which is composed of, for example, a microprocessor and peripheral I/O.

The temperature measurement signal from the temperature measurement element 15 of the heating body 12 of the fixing device 11 described above is input to this control means 50,
Based on the input signal, the temperature control means 51 operates, and the electricity supply to the heating element 14 is controlled to control the temperature of the heating element to a predetermined fixing temperature.

Reference numeral 52 denotes a paper conveying means controlled by the control means 50, which is a driving means typified by a motor or the like.

Reference numeral 53 denotes a fixing unit paper detection means, which is provided at the inlet of the transfer material sheet P of the fixing device 11 as shown in FIGS. 2 and 3, and detects the presence or absence of paper (sheet) P in the fixing unit. and transmits the signal to the control means 50. The paper detecting means 53 can use various known sensors such as a reflective or transmissive photo sensor, or a mechanical sensor such as a microswitch.

Reference numeral 54 denotes at least one paper detection means provided at a location other than the above-mentioned fixing section paper detection means on the paper conveyance path (sheet path) of the apparatus, and this example detects the presence or absence of paper in the paper feed section. It is a paper feed detection means for detecting, and transmits a paper presence/absence signal to the control means 50.

Reference numeral 55 denotes an abnormality detection means of the main body of the image forming apparatus, and an example of the detection target is paper feed jam.
(can be used in combination with 0). An abnormality detection signal from the means 55 is input to the control means 50.

Reference numeral 56 denotes a display means controlled by the control means 50, and is a display means composed of, for example, an LCD or a 7-segment LED.

In the flowchart of FIG. 5, SEQ is a subroutine, and is called and executed as an internal process of the control means 50 every time there is a request from the main routine. Therefore, ■. When the occurrence of an abnormality in the image forming apparatus is detected based on the abnormality detection means 55 during operation of the image forming apparatus (Ye in step S1).
s), subsequent paper feeding from the paper feeding means 7 (FIG. 1) is stopped (step S2); ■. The control means 50 checks whether there is paper in the fixing section of the fixing device 11 based on the signal from the fixing section paper detecting section 53 (step S3). When there is no paper (No in step S3), the control means 50 immediately or after a predetermined period of time stops the paper conveyance means 52, stops all means, interrupts the operation of the apparatus, and displays an error mode on the display means 56. Prompts the operator to take action to deal with the abnormality by displaying a message according to the situation (Steps S7 and S8) ■. When there is paper (Yes in step S3), the control means 50 determines whether the presence of paper is due to a paper jam in the fixing unit (step S4), and if it is due to a jam, the control means 50 executes step Steps S7 and S8 are executed to prompt removal of the jammed paper.

[0044]■. When there is no jam, the paper conveying means 52
By continuing the operation and the temperature control of the heating body 12 of the fixing device 11, the conveyance and fixing of the paper P with the unfixed image portion existing in the fixing device 11 is continued without interruption, and the conveyed paper P is continued without interruption. When the trailing edge of P passes the fixing unit paper detection means 53 and the signal from the fixing unit paper detection unit 53 becomes paper out, and the predetermined time t required for the paper to pass through the fixing unit has elapsed, the paper is removed. The conveying means 52 and the temperature control are stopped to interrupt the operation of the device, and the display means 56 is activated to prompt for troubleshooting (step S5).
・S6).

[0045] During the above paper conveyance, a jam (
It also detects the occurrence of jams (e.g. jams wrapped around paper ejection rollers) and handles the jams.

[0046]

As described above, according to the present invention, the interruption of the operation of the image forming apparatus when an abnormality occurs can be detected by the presence of recording paper in the fixing unit by the fixing section paper detection means. If the recording paper is being fixed, the operation of the apparatus will not be interrupted until the recording paper has been conveyed and passed through the fixing means, and the operation of the apparatus will be interrupted after the recording paper has passed through the fixing means. There is no possibility that the operation of the apparatus is interrupted due to the toner remaining in the fixing means, and the above-mentioned conventional problems caused by such a situation are solved.

[Brief explanation of the drawing]

FIG. 1 A schematic diagram of an example of an image forming apparatus to which the control method of the present invention is applied.

[Figure 2] Schematic diagram of the fixing device used in the image forming apparatus

[Figure 3] Schematic diagram of another example of the fixing device

[Figure 4] Block diagram of control system

[Figure 5] General flowchart of control

[Explanation of symbols]

4 Photosensitive drum 9 Transfer discharge device 11 Fixing device 12 Heating body 16 Fixing film 19 Pressure roller P Recording paper (transfer material sheet) 50 Control means 51 Temperature control means 52 Paper conveyance means 53 Fixing unit paper detection means 54 Paper feed detection means 55 Equipment abnormality detection means 56 Display means

Claims (2)

[Claims] 1. Image formation in which an unfixed image of target image information is formed by an image forming unit on recording paper fed from a paper feeding unit, and the unfixed image is fixed by a fixing unit to form an image. The apparatus is provided with an apparatus abnormality detection means for detecting an abnormality in the image forming apparatus, and a fixing unit paper detection means for detecting whether or not recording paper is present in the fixing means, If an abnormality is detected, the subsequent feeding of paper from the paper feeding means is stopped, and when the presence of paper in the fixing means is detected based on the fixing section paper detection means, a signal from the fixing section paper detection means is A method for controlling an image forming apparatus, comprising: stopping the apparatus drive and fixing operation after the paper runs out and the recording paper has passed through at least a fixing section; and displaying on a display means the occurrence of an apparatus abnormality. . 2. The fixing means heat-fixes the image using a fixedly supported heating body and a pressure member that presses against the heating body and brings the recording paper into close contact with the heating body through a film. 2. The method of controlling an image forming apparatus according to claim 1, further comprising the following steps.