JPS63296078A - Image forming device - Google Patents

Abstract

PURPOSE:To quickly remove a transfer material without contaminating its carrying means by a toner at the time of a carrying failure of the transfer material, by providing an elevating means on a transfer material carrying means, and providing the carrying means so that it can come into contact and can be separated to and from a photosensitive body. CONSTITUTION:A carrying means 39 provided with a carrying belt 26 is supported by a roller 41 provided on a lifter frame 40, the frame 40 is supported by a cam 43, and the belt 26 is provided so that it can come into contact and can be separated to and from drums 11-13 by a rotation of a cam axis 42, by which an elevating means 44 is constituted. In a state that this elevating means 44 has descended, the carrying means 39 can be drawn out to the outside of a device by opening a prescribed door. According to this constitution, in case when a carrying failure of a transfer material 46 has been generated, the carrying means 39 is allowed to descend and drawn out to the outside of the device, therefore, transfer paper can be removed quickly without contaminating the transfer means 39 by a toner which has adhered to a drum, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus (11) by transferring an image formed at an image forming station onto a transfer material conveyed to the image forming station by a conveying means. In particular, it can be suitably applied to an electrophotographic color image forming apparatus that is equipped with a plurality of image forming stations and forms a color image, and is described in connection with such a color image forming apparatus in the Wood Specification. However, it is not limited to this.

' ° and I Conventionally, an image forming apparatus using an electrophotographic process includes an image forming station that forms a latent image using light, magnetism, electric charge, etc., and visualizes the latent image to obtain a visible image; It has a conveying means for conveying a transfer material to the image forming station in order to transfer the image of the image forming station-E, and a fixing means for fixing the image transferred on the transfer material to the transfer material. are doing.

The image forming station has, for example, an electrophotographic photoreceptor or other image forming medium having various characteristics and shapes, and is further provided with various latent image forming means, developing means, etc. corresponding to the image forming medium. configured.

Conveyance means can be roughly divided into two types: one consists of a pair of rollers that convey the transfer material by sandwiching it in a transfer material conveyance path, and the other consists of a roller pair that conveys the transfer material by sandwiching the transfer material. There is also a configuration in which the transfer material is transported from the transfer material supply port to the entrance of the fixing device.

If a roller configuration consisting of a plurality of roller pairs is used as a conveying means, the leading edge of the transfer material is pinched by the rollers many times, resulting in damage to the leading edge of the transfer material.
For this reason, it is difficult to say that it is an excellent conveyance method in terms of high conveyance speed and conveyance stability depending on the type of transfer material, and also because the length of transfer material that can be conveyed is determined by the distance between each roller. In addition, there are restrictions on the size of the transfer material used.

On the other hand, in a conveyance means configured to use a belt-like conveyance material (conveyance belt) to convey the transfer material to the transfer position of the image forming medium and further to the fixing means, the transfer material is fixed from the supply inlet. c1
! Since the transfer material is conveyed while being placed on the conveyor belt until it is transferred, it has the advantage that conveyance defects are extremely rare compared to roller configurations in which the transfer material is conveyed by roller rotation. In addition, in the roller-structured conveyance means, there are many places where various members in the image forming apparatus and the transfer material come into sliding contact, and the transfer material may become electrically charged due to friction, and if the transfer material is paper, it may generate paper dust. However, a conveying means using an m-transfer belt does not have such a problem.

Although the conveyance means consisting of a conveyor belt has many advantages as described above, it still has problems in handling methods for stains on the surface of the conveyor belt and poor conveyance of the transfer material. Contamination on the surface of the conveyor belt contaminates the back side of the image surface of the transfer material, and when an image is transferred from the surface of the image forming medium to the surface of the transfer material, it leads to a decrease in transfer efficiency and causes uneven transfer. Contamination on the conveyor belt surface is mostly due to toner adhesion, and can be broadly classified as toner scattered from the developing means installed on the conveyor belt, that is, the developing device for electrophotographic processes that contains developer. There are two types: toner that has adhered to the surface of the forming medium and toner that has been transferred and adhered to the surface of the conveyor belt.

The most serious cause of toner adhesion on the surface of the conveyor belt is the untransferred recorded image that remains on the surface of the photoreceptor after the transfer material that caused the conveyance defect is removed from the conveyor belt. is in contact with and adheres to the surface of the conveyor belt.

For the above-mentioned reasons, in a conveyance means using a conveyor belt, a conveyor belt cleaning mechanism is required to clean toner adhering to the surface of the conveyor belt. however,
If fake toner adheres to the surface of the conveyor belt, such as an image formed on the surface of an image carrier, it is difficult to clean it easily because the conveyor belt is charged by the transfer charging device. The actual situation is that the toner-attached portion must be passed through the conveyor belt cleaning mechanism many times.

When it comes to handling defects in transfer material conveyance, when removing transfer materials that have caused conveyance defects from inside the device, we use a conveyor belt mechanism, which is relatively large and heavy compared to devices that use other conveyance mechanisms, to remove the defective transfer material from the inside of the device. Since the operator's hand must be moved by the space required for the operator's hand to enter from the body, a large amount of force is required from the operator, and the device also has the disadvantage of becoming larger due to the space in which the conveyor belt mechanism moves.

Furthermore, the transfer material on the conveyor belt.

Since it is adsorbed onto the conveyor belt by static electricity, it is very difficult to peel off, and if the transfer material is forcibly peeled off mechanically, there is a risk of damaging the surface of the conveyor belt.

l-As mentioned above, the conveyance means that conveys the transfer material using a conveyor belt has an excellent ability to convey the transfer material, but once a conveyance failure occurs, it is difficult to remove the transfer material, and the conveyor belt becomes dirty. This has the disadvantage of causing image deterioration.

Furthermore, fixing means can be roughly divided into those that use heat to fuse the image to the transfer material and those that use pressure to adhere the image onto the transfer material, but heat has far superior fixing properties. Many methods are used to establish usage. Furthermore, in heat-based fixing means, the so-called heated roller fixing method, in which the transfer material is held between heated rollers and conducts heat as it passes through, is used to improve fixing performance.

It is used in many image forming apparatuses because it is excellent in terms of energy efficiency.

However, in the hot roller fixing method, when a long transfer material is used in the image forming apparatus, the vibrations that occur when the leading edge of the transfer material is held between the rollers cause the image to be transferred from the image forming medium to the transfer material. This has the disadvantage that the image is transmitted to the trailing edge of the transfer material midway, causing a deterioration in the quality of one image. Furthermore, it also has the disadvantage that fixing performance depends on the thermal capacity of the transfer material.

For this reason, in the conventional technology, in order to eliminate the defects described in A loop of the transfer material is formed, and vibrations from the fixing roller are absorbed by the loop portion of the transfer material, thereby preventing deterioration of image quality.

Also, for heat capacity problems, usually! & also sets the heat amount for the transfer material that is used a lot, and when recording on a transfer material with a larger heat capacity, the feeding speed of the fixing roller is further slowed down to reduce the heat t6 applied to the transfer material at the medium time. The aim is to increase the fixing properties.

However, when a heat roller is used as a fixing means,
As a transfer material, transfer material with large heat capacity (!j4 fat sheet,
When using postcards, cardboard, etc.), there is an extreme difference between the transfer material conveyance speed of the conveyance means and the feed speed of the fixing roller, which is decelerated, especially when long transfer materials are used. A large loop of transfer material may occur in front of the fusing roller.
There have been problems in that the unfixed recorded image comes into contact with the conveyance path, destroying the recorded image, or the stiffness of the transfer material causes the loop to return, resulting in poor conveyance. In order to solve this problem, it is necessary to widen the number of transfer materials in the fixing-first stage and to provide a large space in the conveyance path, resulting in an increase in size and a decrease in rigidity of the image forming apparatus.

As understood from the above explanation, the conveyance means.

Even when the best fixing method is used, there are many problems.

Therefore, an object of the present invention is to improve the developer (toner) of the conveying means.
It also prevents the unfixed image from coming into contact with the conveying path due to the loop of the transfer material formed between the conveyance means and the fixing means, resulting in disturbance of the recorded image and loose return of the transfer material. An object of the present invention is to provide an image forming apparatus capable of solving conveyance defects caused by defects.

Another object of the present invention is to provide an image forming apparatus that can remove defective transfer material very easily and quickly even if a transfer material failure should occur.

Another object of the present invention is to provide an image forming apparatus which eliminates the need for a transfer material loop escape space formed between a fixing means and a conveying means, and which can achieve miniaturization and high rigidity of the apparatus. It is.

Still another object of the present invention is to provide an image forming apparatus that can form high quality images using various transfer materials.

8.1 The objectives listed in 2 above are achieved by the image forming apparatus according to the present invention. In summary, the present invention provides two transport stages for transporting a transfer material to an image forming station in order to transfer an image formed at the image forming station, and a transport means separated from the image forming station. an image forming apparatus, characterized in that the image forming apparatus has an elevating means for moving the image forming station to a fixed position, and the elevating means is operated in accordance with the image forming operation state to bring the conveying means into contact with or away from the image forming station. It is. ' Next, the image forming apparatus according to the present invention will be explained in more detail with reference to the drawings. In this embodiment, the present invention is an electrophotographic laser beam color printer (hereinafter referred to as rLBP apparatus). ) is embodied in

A plurality of image forming stations are arranged side by side, and a modulated laser beam is used as a light source to form toner images in three colors, for example, magenta, cyan, and yellow, using an electrophotographic process, and each color image is sequentially transferred onto a transfer material. Since the LBP apparatus which obtains a full-color image by superimposing the color image on the image and using a subtractive color mixing method is well known to those skilled in the art, a detailed explanation thereof will be omitted.

Next, the configuration and operating mode of the LBP apparatus will be briefly explained with reference to FIG. 1. In this embodiment, the LBP apparatus 1 has three image forming stations A, II, A conveying means 39 equipped with a conveying belt 26 is disposed below the forming stations E, Il, and III for conveying the transfer material, and at the exit of the conveying means, the image on the transfer material is transferred to the transfer material. A fixing means 56 having a pair of heat rollers 56a, 56b is arranged for thermal fixing. Each image forming station E, n, m is a means for forming an image, for example, an image forming medium rotating at a constant speed, that is, in this embodiment, an electrophotographic photosensitive drum 11, 12, 13, a charger 14,
15.16, developer 17.18.19, transfer charger 20
．． 21.22. and a cleaner 23.24.25.

The image signal input to each image forming station is composed of three image signals obtained by color-separating the recorded original image into red, blue, and green components, and the image signal of each color component is continuously (
serially) to the image forming station.

More specifically, the image signals are input at regular intervals in the order of red, blue, and green components. When an LBP device angle image signal is input from an external device.

The green component image signal sent first is manually input to the laser scanner 2 of the image forming station (2).

The laser scanner 2 applies a laser beam 5 modulated and emitted from a built-in laser diode based on the image signal of the green component to a rotating polygon mirror to create a parallel scanning state, and then a folding mirror 8. Via
By operating the laser scanner 2, which projects an image onto the surface of the photoreceptor drum 1.1 rotating at a constant speed and scans it in a direction perpendicular to the rotational direction of the photoreceptor drum 11, the charger 14 generates an image. A latent image of the green component of the recorded image is formed on the uniformly charged surface of the photosensitive drum 11.

The latent image formed on the photoreceptor drum 11 is developed with magenta toner filled in the developing device 17 and visualized. The recorded image visualized by the magenta toner is placed a on the conveyor belt 26 and transferred onto the conveyed transfer material 46h by the action of the transfer band 'wn20.

After the green component image signal is completed, the red component image signal is input to the laser scanner 3, and through the same process as described above, a cyan image is formed on the photoreceptor drum 12 by the cyan toner in the developing device 18. is visualized. The cyan image is transferred to overlap L of the magenta image on the transfer material 46 that is conveyed from the direction of the photoreceptor drum 11.

When the red component image signal is completed, the subsequently input blue component image signal is input to the laser scanner 4 and undergoes the same process as described above to form a yellow image on the surface of the photoreceptor drum 13. The yellow image is transferred to be superimposed on the cyan image on the transfer material 46 that is conveyed on the conveyor belt 26 from the direction of the photoreceptor drum 12 .

As a result of the above-mentioned operation, recorded images made of magenta, cyan, and yellow color toners are transferred onto the transfer material in a layered state, and then the transfer material 46 is sent to the fixing means 56 by the conveyor belt 26.

The toners of each color on the transfer material 46 pass between heated rollers 56a and 56b in the fixing means 56, where heat and pressure are applied to them, and the toners are fused together to perform subtractive color mixing to form a full-color recorded image. fixed on the surface.

Here, the image at each image forming station is always transferred to the transfer material 4.
If the images are not transferred to the same position on each photoreceptor drum 11, the color of the image will shift and the image quality will deteriorate significantly.
．． The rotation circumferential speed of 12.13 and the conveyance speed of the conveyor belt 26 are controlled to match with extremely high precision, and for this purpose, the rotation shafts of each photoreceptor drum 11, 12.13 and the conveyor belt 26 are driven. An encoder is provided on the rotation shaft of the drive roller 35, and the rotation speed and wow and flutter of each member can be detected.

Next, LB! The transfer material conveying means 39 of ``121'' will be explained in more detail.

The transfer material 46 cut into a standard size is loaded into the cassette 45. When the cassette 45 is installed in the LPB equipment 211, the cassette 45 presses the cassette detection switch 47 and sends a cassette installation signal to the microcomputer in the LPB equipment.

When the cassette 25 is loaded into the LBP device l.

The transfer material 46 is pressed against the feed roller 48 . When the feed roller 48 rotates, the feed roller 48 and the transfer material 4
Due to the difference between the frictional force between 6 and the frictional force between each transfer material 46,
The transfer material 46 pulled out from the inside of the cassette 45 is conveyed while being held by the registration rollers 49, and the leading edge of the transfer material enters the optical path between a lamp 50 and a photosensor 51 provided for detecting the leading edge of the transfer material. The light that is being irradiated is sent out until it is blocked. When the leading edge of the transfer material blocks the optical path from the lamp 50 to the photosensor 51, the registration rollers 49 stop rotating while holding the transfer material 46 between them.

When a latent image begins to be formed on the surface of the photoreceptor drum 11 due to the operation of the laser scanner 2, the registration roller 49 rotates again at the timing so that the magenta color toner image can be transferred. The transferred transfer material 46 is sent onto the conveyor belt 26.

The conveyor belt 26 is made of a transparent or semi-transparent resin material such as polyurethane, and during operation, the surface is charged using an adsorption charger 33 so that the transfer material 46 can be stably conveyed. The material 46 is electrostatically attracted. Furthermore, the transfer material 46 sent out from the registration rollers 49 is transferred to the conveyor belt 26.
- The conveyor belt 26 and the transfer material 46 are pressed by the driven roller 34 and the presser roller 52 so that the transfer material 46 is electrostatically attracted well without wavering.

Lamps 27, 29, and 31 are provided at the bottoms of the developing devices 17, 18, and 19 containing toner of each color, respectively, and are capable of projecting approximately parallel light onto the surface of the conveyor belt 26. on the other hand,
Inside the conveyor belt 26 illuminated by the lamps 27, 29, 31, there are photodiodes 28, 30, respectively.
．． 32 is provided, and the lamp 2 transmitted through the conveyor belt 12
It is possible to detect the amount of light projected from 7, 29, and 31.

The transfer material 46, onto which the recorded images of each color toner are transferred one after another from each photoreceptor drum 11, 12, 13, is attached to the separation claw 36.
By the action of , it is peeled off from the surface of the conveyor belt 26,
It passes through the conveyance path 53, enters the fixing means 56, where one image is fixed, and then is discharged to the tray 6o.

On the other hand, the conveyor belt 26 from which the transfer material 46 has been separated is cleaned of toner and paper powder adhering to the surface thereof by a conductive blade 37, and electricity is removed.

Transfer charger described above 20.21.22. Photodiode 28, 31.321. Conveyor belt 26, adsorption charger 33, driven roller 34. Drive roller 351 separation claw 36
．． Each member of the conductive blade 37 is assembled on a frame 38 to constitute a conveying means 39.

The conveying means 39 is supported by rollers 41 provided on the lifter frame 40. The lifter frame 40 is supported by a cam 43, and by rotating the cam shaft 42, the cam 43 can be rotated to change its height as shown in FIGS. 1, 2, and 3. The camshaft 42 is connected to a position sensor, and the position of the lifter frame 40 can be detected based on the signal output state from the position sensor. Further, the camshaft 42 is connected to a drive source via a clutch mechanism controlled by a microcomputer within the LBP device 1.

The above lifter frame 40. Coro 41. Cam 42: Cam 4
3 and the like constitute an elevating means 44 that changes the height position of the conveying means 39. The elevating means 44 and the conveying means 39 are
When the conveying means 39 is held at the highest position by the lifting means 44, the conveying belt 26 and each photoreceptor drum 11.12.1
It is set so that three surfaces can be contacted.

Next, as shown in FIG. 2, by slightly lowering the position of the transport unit 39, the transport belt 26 and each of the photosensitive drums 11, 12, 13 are brought into a non-contact state. In addition, in such a state, the transfer material 46 is transferred to each photoreceptor drum 11, 12.
．． 13 (see FIG. 4).

In this embodiment, the position of the conveying means 39 shown in FIG. 2 is referred to as an "intermediate position."

The conveyance distance A from the nip portion of the rollers 56a, 56b (7) of the fixing means 56 to the drive roller 35 is the same as that of the image forming apparatus 1.
is determined by the shortest usable transfer material length.

Furthermore, in this embodiment, the transfer material is electrostatically attracted onto the conveyor belt 26 in order to ensure the conveyance of the transfer material. With this configuration, the transfer material is attracted and conveyed to near the turning point of the conveyor belt of the drive roller 35. Therefore, the actual space used for the transfer material to form a loop is shorter than the above-mentioned transport distance A, as shown by the transport distance A'.

Further, as shown in FIG. 3, when the conveyance belt 26 is driven with the conveyance means 39 lowered and positioned at the "lowest position" to convey the transfer material 46, the transfer material 46 is separated from the conveyor belt by the separation claw 36. 26 and is configured to be sent out to a discharge path 62. The transfer material 46 sent out to the discharge path 62 in this way does not pass through the fixing device 56, as shown in FIG. 5, and the discharge cover 63 is opened.
It is possible to take out the LBP device 2fl. At this time, as shown in FIG. 6, when the conveying means 39 is lowered to the lowest position as shown in FIG.
When the front exterior j7i64.65 is opened and the conveying means 39 is pulled toward the user, the conveying unit 39 can be pulled out of the apparatus while being supported by the rollers 43.

When the conveying means 39 is pulled out, the pin of the position switch 69 that was pressed by the conveying means 39 returns to its original position due to the force of the built-in spring, and the current flowing through the position switch 69 is cut off. By detecting the voltage Vt value state of the position switch 69, the microcomputer in the LBP device determines whether the conveying means 39 is placed in the correct position in the device.

Next, an explanation will be given of an image forming operation when forming an image on a transfer material having a large heat capacity in the LBP apparatus having the above configuration.

In this embodiment, the timing of the image forming operation sea fence is set based on the signal from the photodiode 51. First, a method of setting the activation timing based on the signal from the photodiode 51 will be explained.

In FIG. i1, when the transfer material 46 is fed into the recording apparatus l by the registration rollers 49, the illumination light of the lamp 50 that was irradiated to the photodiode 51 is shut off while the transfer material 46 passes. When the rear end of the transfer material 46 passes between the lamp 50 and the photodiode 51, the photodiode 51 is again irradiated with illumination light, and the signal output value from the photodiode 51 changes.

From the photodiode 51 to each photosensitive drum 11.12.
13 and the nip between the conveyor belt 26 and the conveyance speed of the transfer material are fixed. .13 and the conveyor belt 26. In other words, the photosensitive drum 11
The time required for the rear end of the transfer material 46 to pass through the nip is calculated by dividing the transport distance B from the nip of the photosensitive drum 11 to the photodiode 51 by the transfer material transport speed in FIG. It can be calculated by

The thus obtained time for the trailing edge of the transfer material to pass through the nip portion of the photosensitive drum is recorded, and an image forming operation is performed based on the signal from the photodiode 51.

In FIG. 1, when a transfer material with a large heat capacity, such as a resin sheet, is placed in the cassette 45, the recording apparatus l
Except for reducing the conveyance speed of the fixing device 56, the normal image forming operation is performed until the rear end of the resin sheet passes through the nip portion of the photoreceptor drum 13, and three-color recorded images are superimposed on the resin sheet. Transcribe.

When a set time elapses after the rear end of the transfer material resin sheet passes through the photodiode 51 and passes through the nip portion of the photoreceptor drum 13, the lifting means 44 is activated and the conveying means 39 is moved to the position shown in FIG. At the same time, the conveying speed of the conveying means 39 is lowered to the intermediate position shown in FIG.
The conveying speed of the conveying means 39 is reduced until it becomes approximately equal to the conveying speed of. As a result, the difference in conveying speed between the fixing means 56 and the conveying means 39 becomes extremely small, and loop formation of the resin sheet is no longer performed. Therefore, even when an image is formed on a long resin sheet, the transfer material does not form a loop after passing the nip portion of the photoreceptor drum 13.

When the resin sheet is conveyed into the fixing means 56 and the rear end of the sheet passes the photodiode 55.

The conveying speed of the conveying belt 26 is increased again, and is returned to the same speed as the rotating circumferential speed of each photoreceptor drum.

The elevating means 44 operates at the same time as the transporting speed of the transporting means 39 returns to the original state, raises the transporting means 39, and fixes the transporting means 39 at a position where image formation is possible.

By manipulating the image forming operation sea fence mentioned above,
Image formation is performed on the large transfer material on the heating table I11. Furthermore, when forming an image in only one arbitrary color rather than in full color with this apparatus, when the rear end of the resin sheet passes through the nip of the photosensitive drum where the image forming operation was performed, the lifting means 44 is activated. By lowering the conveyance means 39, it is possible to perform good fixing without increasing the loop amount of the transfer material.

In the present invention, depending on whether the heat platform of the transfer material is large or not,
Although the image forming operation sea fence is different, methods for detecting the difference in heat capacity of the transfer material include a method in which the operator manually inputs information on the heat capacity of the transfer material into the device using a variable switch, or a method by inserting a special cassette. Known detection methods can be used, such as an information input method and an information input method based on a combination of different types of sensors using an optical sensor and a contact sensor used when recording on a transparent resin sheet.

Next, a method for detecting transport failure of the transfer material 46 in the LBP apparatus 1 will be described. Basically, when the signal output value from the photodiode installed on the downstream side in the conveyance direction does not change even after a set time has passed after one operation, that is, when the lamp that illuminates the photodiode If the transfer material passes through the optical path between the photodiodes and does not block the light emitted from the lamp, it is determined that a transfer material failure has occurred in the transportation path leading to the photodiodes. However, a conventionally known method for detecting defective transfer material conveyance is used.

1-The placement setting time is the time required for the transfer material to be conveyed to the location where each conveyance failure detection means is provided during normal operation of the LBP apparatus 1.

Examples of the setting time and setting conditions used in this embodiment are as follows.

Setting time a: After outputting the rotation command signal of feed roller 48, TI ± 1 second b = After outputting the rotation command signal of feed roller 4, TZ ± 1 second // Q: After changing the photodiode 28.30 signal output value T3 ± 1 Seconds d: T4±1 second after photodiode 32 signal output value change // 9: 15 seconds after photodiode 55 signal output value change f: T6±1 second after photodiode 55 signal output value change” g: L B Time required from when the transfer material 46 is conveyed into the P device l until it is discharged h: Time required for the fixing device 56 to convey two sheets of the transfer material 46 and perform the fixing operation // i: Conveyance belt 26 The times T1 to T6 used within the set time a-f required to move the circumferential length of the repair are arbitrary set times.

Using the above-mentioned set time, the operation sea fence when a transfer material conveyance failure occurs in the LBP device 1 will be explained.

According to the research conducted by the present inventors, the main locations where transport defects occur in the LBP device are (1) the cassette 45, (
2) Conveyor belt 26. (3) II2 feed path 53. (4) It was found that the problem occurred at four locations in the fixing device 2t56.

LBP according to the invention? T! In step 11, if a conveyance failure occurs at the above four locations, a transfer material removal operation sea fence that is different from the place where the conveyance failure occurs is started.
The operating sea fence when a transfer material failure occurs at the above four locations will be explained with reference to FIGS. 8 to 11.

(1) Defective transport of cassette 45 A transport failure of cassette 45 means that the transfer material 46 is not transported from inside the cassette 45 into the LBP apparatus l. As a detection method, the signal output value from the photodiode 51 changes to a certain value or more even after a set time a has passed since the feed roller 48 rotates according to a command from a microcomputer installed in the LBP device l. If not,
That is, if the tip of the transfer material 46 does not block the optical path from the lamp 50 to the photodiode 51, the microcomputer will determine that there is a conveyance failure and will proceed to step 1 in FIG.
02), conveyance failure, operate the removal sea fence l (Fig. 9).

Conveyance failure, removal sea fence l (FIG. 9) indicates that the transfer material that caused the conveyance failure in step 112 is removed after the recording operation starts.
Different operations are performed depending on whether it is the first object to be conveyed or the number of sheets during continuous recording. First, the transfer material that has caused a conveyance failure is the first to be conveyed after recording starts. If the transfer material has been transferred (Yes in step 112), there is no transfer material on the downstream side in the transport direction from the location where the transport failure occurred in the transport path.

Therefore, the microcomputer stops the recording operation of the LBF device 1, and lights up the transport failure warning 86 on the operation panel E shown in FIG. 7 (step 113).

The operator pulls out the cassette 45 from the LBP apparatus 1 (step 114), removes the transfer material that has been conveyed poorly, and then inserts the cassette 45 again. When the cassette 45 is inserted, the cassette detection switch 47 is pressed, and the cassette detection switch 47 becomes conductive again (step 115).
The above microcomputer has a cassette detection switch 4
In step 116), the conveyance failure warning 86 is canceled by the signal from 7, and the conveyance failure removal sea fence 1 is terminated.
The operation of the BP device 1 is restarted.

If a conveyance failure occurs in the cassette 45 during continuous recording (No in step 112), the microcomputer first stops the operation of the feed roller 48 and the registration roller 49, and stops the conveyance by the conveyor belt 26. An image forming operation is then performed on the transferred transfer material (step 117).

In the image forming operation after a conveyance defect is detected, toner is applied one after another from the upstream side in the conveyance direction in accordance with the conveyance of the transfer material that was conveyed into the LBP device one sheet ahead of the transfer material that caused the conveyance defect. The microcomputer controls each unit 1@ to stop image formation. This control prevents toner images from adhering to the surface of the conveyor belt 26.

To explain further, when a toner image is transferred to the transfer material sent out from the cassette 45 one sheet before the transfer material that caused the conveyance failure, the developing device is removed from the surface of the photoreceptor drum where the transfer was performed, or The next image formation is made impossible by stopping the emission of the laser light irradiated onto the photoreceptor drum. This operation is repeated, and when the final yellow toner image has been transferred to the transfer material, the image forming operation on each photoreceptor drum is stopped.

After the set time g has elapsed after the detection of a conveyance failure, the microcomputer stops the image forming operation of the LBP device 22i, displays a conveyance failure warning 86 on the operation panel (step tta), and then performs the process shown in FIG. Returning to step 114, the sea fencing is carried out in the same way as when the conveyance of the transfer material failed for the first time after the start of the image forming operation.

Note that after the conveyance failure is detected, before the set time g has elapsed, the transfer material that was conveyed one sheet before the transfer material that caused the conveyance failure is subjected to an image forming operation and is discharged from the fixing means 56.

(2) Conveyance defects on the conveyor belt 26 Conveyance defects on the conveyor belt 26 can be roughly divided into two types. One is that the transfer material conveyed by the registration roller 49 gets jammed at the presser roller 52, and the conveyor belt 26
Another reason is that the electrostatic adsorption force on the surface of the photoreceptor drum 11, 12, and 13 is stronger than the electrostatic adsorption force on the surface of the conveyor belt 81 while the transfer material is being conveyed. ,
The cause is that the transfer material is attracted to the surface of the photoreceptor drum 11, 12, 13, is carried to the cleaner 23, 24, 25, and becomes clogged there.

The conveyance failure at the presser roller 52 occurs when the transfer material 46, which is held between the registration rollers 49 with the optical path between the lamp 50 and the photodiode 51 completely blocked by the tip, is rotated by the registration rollers 49. If the light does not pass through the optical path from the lamp 27 to the photodiode 28 within the set time a, that is, if the signal output value from the photodiode 28 does not change beyond a certain value, it is detected by the microcomputer. Ru. Transfer material clogging in the cleaner 23 occurs when the signal output value from the photodiode 30 does not change to a certain value or more within the above-mentioned set time after the signal output value of the photodiode 28 changes, as in the L-described detection method. is detected. The remaining 24.25 parts of the cleaner was also clogged with transfer material.

Using photodiodes 30, 32, and 55, detection is performed based on the set times c and c in the same manner as in the above method.

Here, using FIG. 8 and FIG. 1O, conveyance failure in the conveyor belt 26 portion and removal sea fence will be explained.

At steps 105, 106, and 107 in FIG. If it is the first thing transported during recording or after the start of continuous recording (step 11)
9.120) Immediately stop the image forming operation and display a conveyance failure warning 86 on the operation panel of the LBP device 1 (step 121).During continuous recording, one sheet in the middle of conveyance has a conveyance failure. If so (No in step 120), the sea fence in step 123 is activated.

In other words, immediately after detecting a conveyance failure, LBP! All image forming operations except the fixing means 56 in Itll are stopped.

After the conveyance failure is detected, the fixing device 56 is set to 1111 at the time of setting.
After the three-color toner image has been transferred, the fixing operation is performed only on the transfer material that has been sent out from the conveyor belt 26, and the transfer material is discharged onto the tray 60 (step 123).
When the set time period has elapsed, the LBP device t stops the entire image forming operation and displays a conveyance failure warning 86 on the operation panel -1- (step 121).

In FIG. 1, when the operator opens the right front door 64 and the left front door 65 to remove the transfer material that has caused a transport failure, the pins and electrical contacts of the door switches 66 and 67 that were pressed by each front door are , it returns to its original position by the force of an internal spring, cutting off the signal line to the microcomputer.

When the signals from the door switches 66 and 67 are cut off (step 122), the transport defect/removal sea fence 3 shown in FIG. 10 is activated.

When the door switches 68, 67 are turned off, the microcomputer operates the lifting means 44 to lower the conveying means 39 (step 125), and at the same time
The elevating means operation warning 88 is displayed on the operating panel of the BP device 1, and the buzzer 93 is sounded (step 124).
When the lifting means 44 stops operating and the conveying means 39 finishes descending, the lifting means operation warning 88 is canceled and the buzzer 93 stops sounding (step 126).

By the above operation, a space is created between each photoreceptor drum 11, 12, 13 and the conveyor belt 26, and the conveyor means 44 is pulled out from inside the LBP lafil as shown in FIG. Removal becomes possible. or,
The conveyance failure warning 86 is canceled by pressing the reset switch 68 (steps 127 and 128). When the operator pulls out the conveyance means 39 toward the front in order to remove the transfer material that has caused the conveyance failure, the position switch 6
9 is cut off, and a transport means attachment failure warning 69 is displayed on the operation panel of the LBP device 211 (step 14).
1).

When the removal of the transfer material is completed, the conveyance means 39 is re-installed into the LBP mounting l, and the front door is closed, the conveyance means installation failure warning 69 on the operation panel is canceled and the weight 5, which means preparation for operation, is canceled instead. Display 87 is displayed (step 130,
131, 142, 143).

While displaying the weight display 87, the microcomputer confirms whether the image forming operation in which the conveyance failure occurred was an image forming operation on only one transfer material, or a continuous image forming operation in which multiple image forming operations were performed. (Step 1
32) In step 132, if a conveyance failure occurs during the continuous image forming operation, the recorded image is transferred from the surface of each photoreceptor drum 11.12°13 onto the conveyance belt 26, excluding the transfer material that caused the conveyance failure. The transfer material on the way is attracted at regular intervals.

Therefore, when the conditions of step 132 are satisfied, the conveying means 38 is operated for i seconds to move at least the circumferential length of the conveying belt 26, and the transfer material adsorbed on the conveying belt 26 is peeled off by the separation claw 36. After the transfer material is sent to the discharge path 62, the surface of the conveyor belt 26 is cleaned and neutralized by a conductive blade 36. In addition, when using a conveyor belt cleaning mechanism that requires electric power, such as a single-rotation type brush or electrostatic adsorption, unlike the conductive blade 16, it is set to operate for i seconds in synchronization with the operation of the conveyance means 39. .

After the operation of the conveying means 38 for i seconds, the lamp 27.
29, 31, and 50 are turned on, and the presence or absence of the transfer material on the conveyor belt 26 is determined based on the signal output value from each photodiode 28, 30, 32, and 51 (step 134). 1 out of .30.32.51
If the signal output value is different from the reference value at any time, i.e.
The transfer material that was not sent into the discharge path 62 caused the lamp 2 to
If the illumination light from 7.29.31.50 is blocked, a conveyance failure warning 86 is displayed on the operation panel (step 144), the process returns to step 127 of the flowchart, and the transfer material on the conveyance belt 26 is removed. When the signal output values from each photodiode 28, 30, 32, and 51 are all normal (Y
s), first, each photoreceptor drum 11, 12.13 is rotated at least once, and the surface of each photoreceptor drum 11, 12.13 is cleaned using each cleaner 23, 24, 25 (step 146). Each photoreceptor drum 11.12.13
After the cleaning operation is completed, the lifting means 44 is operated, and the cam 43
By the rotation of the conveying means 39, the conveying means 39 is raised again to a position where image formation can be performed (step 136).
In conjunction with the operation of step 4, a lifting/lowering f stage operation warning 88 is displayed on the operating device of the LBP'IIc device 1, and a warning sound is emitted by the buzzer 93 (step 136).

The operation of the elevating means 44 is stopped while the conveying means 39 is raised and supported to the position where the image forming operation is possible. or,
The operation of the buzzer 93 and the elevating means operation warning 88, as well as the operation of the weight display 87, are stopped in conjunction with each other, and the LBP device 1 enters a recording operation standby state, and the conveyance failure/removal sea fence 2 shown in FIG. 10 is terminated ( Steps 139.140
).

Next, step 132 of transport failure and removal sea fence 2
A case will be described in which a conveyance failure occurs when the number of sheets desired for image formation loaded onto the LBP apparatus is one.

If a conveyance failure occurs under the above conditions, only the transfer material that has suffered a conveyance failure will be present in the transfer material conveyance path of the LBP device l. For this reason, the above steps 119 to 13
If the operator removes the transfer material that has caused a conveyance failure within the sea fence No. 2, no transfer material will be left in the transfer material conveyance path.

In step 132 of the flowchart, when the operation proceeds to step 145 depending on the conditions, each lamp 27, 29, 31.50 is turned on similarly to step 134, and the signal output value from each photodiode 28, 30, 32.51 is turned on. The presence or absence of a transfer material on the conveyor belt 26 is then determined.

In step 145, each photodiode 28.3
0.32.51, if there is a photodiode that outputs a value i different from the setting f1 in the microcomputer, a conveyance failure warning 86 will be displayed on the operation panel (step 147), and the sea fence in step 127 In step 145, each photodiode 28, 30, 32.5 is
If all of the output signal values from 1 are normal, the Sea Fence proceeds to step 146. In step 146, each photoreceptor drum 11, 12, 13 and the conveyor belt 26 are cleaned. Specifically, each photoreceptor drum 11, 12.13 rotates at least once, and each photoreceptor drum 11, 12.
12. Each photoreceptor drum 11, which performs the surface cleaning of 13,
At the same time as the cleaning operation in step 12.13, the conveying means 39 also operates for one second to move at least the repairing circumference of the conveying belt 26.

The conductive blade 16 cleans dirt such as toner of each color adhering to the surface of the conveyor belt 26, and the conveyor belt 26
Remove static electricity from the surface.

Further, when using a conveyor belt cleaning mechanism that requires electric power, such as a single-rotation brush or electrostatic adsorption, unlike the conductive blade 16, the cleaning mechanism is set to operate for i seconds in synchronization with the operation of the conveyance means 39.

When the h"rM operation of each photoreceptor drum 11, 12, 13 and the conveyor belt 26 in step 146 is completed, the sea fence operation proceeds to step 136, and the conveyance failure during the continuous image forming operation in step 132 described above is performed. , the same operation as in the removal method is continued until step 140, and the transport failure and removal sea fence 2 are completed.

(3) Poor conveyance between the conveyor belt 26 and the fixing means 56 Most of the conveyance defects between the conveyor belt 26 and the fixing means 56 are caused by the separating claw 36 provided on the conveyor stage 39.
Occurs in B. To explain in detail, the transfer material electrostatically attracted to the surface of the conveyor belt 26 is not peeled off from the surface of the conveyor belt 26 by the separation claw 36, and the transfer material is separated from the conveyor belt 2 by the separation claw 36.
The cause is that it gets stuck between 6 and 6. Another example of a conveyance failure is that the transfer material stops in the conveyance path 53 for some reason and is not conveyed into the fixing means 56.

Detection of conveyance failure at separation claw 36 is performed using photodiode 3.
This is done because the signal output value of the photodiode 55 does not change even after d seconds have passed after the signal output value has changed from the photodiode 55. In addition, a conveyance failure in the conveyance path 53 may occur even after 0 seconds have passed since the signal output value of the photodiode 55 changed.
This is detected when the signal output value of the photodiode 55 does not return to its original value.

When the microcomputer detects a conveyance defect, it executes the "conveyance defect removal sea fence 2" shown in FIG.
Activate. That is.

If the condition is not satisfied in step 108 or 109 of FIG. 8, the operation seafence proceeds to step 119 and determines whether there was a continuous imaging operation or not, as well as i!
! If the image forming operation for the subsequent image is performed, the image forming operation of the LBP device 1 is performed in step 120 by performing different sea fence operations depending on conditions such as whether or not the transfer material that caused the conveyance failure is the first sheet in the image forming operation. (Step 12)
1).

After the image forming operation is stopped, the right front door 64. When the left front door 65 is opened (step 122), the microcomputer activates the transportation defect/removal sea fence 2 shown in FIG.

(4) Conveyance failure in the fixing means 56 section The conveyance failure in the fixing means 56 section is caused by a transfer material jam when the transfer material is discharged. Such a conveyance defect is detected when the signal output value from the photodiode 58 does not change even after f seconds have passed after the signal output value of the photodiode 55 has changed (step l10 in FIG. 8).
, when the conveyance defect detection is performed in step 110, the microcomputer operates the "conveyance defect sea fence 3" shown in FIG. 11, and LBP*! 11 is stopped, and a conveyance failure warning 86 is displayed on the operation panel (step 147). When the operator opens the fixing cover 61 to remove the transfer material that has caused the conveyance failure, the fixing cover switch is activated. 59 is OFF! The current applied to the island is cut off (step 148), the transfer material that has caused a conveyance failure is removed from the fixing means 56, and the fixing cover 61 is removed again.
When the fuser cover switch 57 is closed, the fixing cover switch 57 returns to its original ON state (step 149). When the fixing cover switch 57 is turned ON, the microcomputer determines whether the signal output value from the photodiode 58 is a normal value. (step 150), and if the signal output value from the photodiode 58 is normal in step 150,
The operating sea fence proceeds to step 151, and instead of erasing the transport failure warning 86 on the operation panel, the weight display 8
7 is displayed (step 151).

After the wait is displayed, the temperature adjustment circuit of the fixing means 56 is operated until the temperature of the heat roller in the fixing means 56 rises to a temperature at which the fixing operation can be performed (step 152). When the fixing means 56 is ready for operation, the microcomputer , each photoreceptor drum 11.12.13. Conveying means 39, fixing means, 5
6 for i seconds to fix the recorded image in the middle of recording onto the transfer material adsorbed on the conveyor belt 26, and transfer the recorded image to the tray 60.
At this time, the surfaces of each photoreceptor drum 11, 12, 13 and the conveyor belt 26 are cleaned by the cleaner 23, 24, 25 and the conductive blade 37. After 1 second of operation, each photodiode 2
The microcomputer checks whether the signal output values from 8.30, 32.51.55 are normal (step 15).
4), each photodiode 28.30.32.51.5
If the signal output value from 5 is normal, the microcomputer erases the weight display 87 on the operation panel in step 155, and ends the conveyance failure sea fence shown in FIG. In addition, if at least one of the photodiodes 28.30°32.51.55 shows an abnormal output value in step 154, the conveyance failure sea fence is detected in step 154 or in the conveyance shown in Fig. 1θ. The process advances to step 124 of defective sequence 2, and the sea fencing described above is performed.

In addition to the method using light, known methods such as microswitches and sensors using capacitance can be used as the conveyance defect detection means explained in the above embodiments. In addition to the method using a blade as a conveyor belt cleaning device, there are many other methods such as applying a brush, using electrostatic attraction, using air flow, and using adhesive force. can.

In addition to using the cam mechanism as in the above embodiment for the elevating means for elevating the transport unit, parallel link mechanisms such as pantographs, gear mechanisms using racks and pinion gears, winding mechanism rings using wires and pulleys, Many drive transmission mechanisms may be used, and any configuration of such lifting means may be employed in the present invention.

Furthermore, even in a configuration in which the m-transporting means can be retracted from the photosensitive drum, in addition to the method of moving the transporting means in parallel upward and downward directions as in this embodiment, as shown in FIGS. 12 and 13, A part of the conveying means is set as a rotating shaft, and the conveying means is a rotating part.

It is also possible to use an elevating mechanism that moves the photoreceptor drum away from the surface of the photoreceptor drum.

To explain more specifically, in FIG. 12, the center of rotation of the conveyance means during the evacuation movement is the conveyance roller 2 on the paper feeding side.
04, and the conveyance roller 20 is located on the fixing roller side.
5 descends, the conveyor belt 206 moves toward the photoreceptor 20.
It becomes possible to save from 0. Further, in FIG. 13, the center of rotation of the conveying means during the evacuation movement is the conveying roller 214.
215 , and by lowering the front side of the conveying means 211 , the conveying belt 216 can be retracted from the photoreceptor 210 .

In the above embodiment, the conveying means is automatically retracted using the seven cutter units, but the retractor is also capable of retracting the transport means by the force of the operator. At this time, use a solenoid or the like to prevent the surface of the photoreceptor from being moved during the photoreceptor surface cleaning operation and causing contact between the photoreceptor surface and the conveyor belt surface by accidentally moving the conveyance means. A fixed holding mechanism is required to prevent the conveying means from moving from the retracted position.

Further, in this embodiment, an LBP apparatus using a plurality of image forming stations has been described, but the present invention has a first embodiment.
As shown in FIGS. 2 and 13, there are image forming apparatuses having one image forming station, that is, using one image forming medium, and furthermore, image forming apparatuses using different methods of forming a latent image on the surface of the image forming medium. It can also be embodied in a forming device.

11 vertical difference j The image forming apparatus according to the present invention is provided with an elevating means that allows a transfer material conveying means for conveying a transfer material to an image forming station equipped with an image forming medium to be retracted from the surface of the image forming medium, The structure is such that the operation of the elevating means is controlled in accordance with the forming operation state, and the conveying means is brought into contact with or separated from the surface of the image forming medium.

(1) When a transfer material failure occurs, it is possible to quickly remove the defective transfer material without contaminating the conveyance means with toner.

(2) It is possible to extremely reduce toner contamination of the conveyance means, a simple cleaning mechanism for the conveyance means is sufficient, and the conveyance path can be downsized.

As a result, the image forming apparatus can be made smaller and more rigid.

(3) A space formed between the conveyance means and the fixing means for the loop escape of the transfer material is not required, and the image forming bag can be made smaller and more rigid.

(4) Good quality of the recorded image can be maintained even if the fixing means and the conveying means are brought close to each other, and also transfer materials of various lengths and materials can be used.

It has various features.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a full-color LBP device, which is an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a sectional view of the structure of the apparatus shown in FIG. 1 when the conveying means is fixed at an intermediate position. FIG. 3 is a sectional view of the structure of the apparatus shown in FIG. 1 when the conveyance means is fixed at the lowest position. FIG. 4 is a cross-sectional view of the structure of the apparatus shown in FIG. 1, showing the conveying path when the transfer material is conveyed in the state shown in FIG. 2. FIG. FIG. 5 is a cross-sectional view of the structure of the apparatus shown in FIG. 1, showing the conveyance path when the transfer material is conveyed in the state shown in FIG. FIG. 6 is a plan view showing a state in which the conveying means is pulled out from the LBP device of FIG. 1. FIG. 7 is a plan view showing the operation panel of the device shown in FIG. 1. 8 to 11 are operational sea fence diagrams of the LBP device of FIG. 1. FIG. 12 and FIG. 1: LBP device 2.3.4: Laser scanner 11.12.13: Photosensitive drum 17.18.19: Developing device 20.21.22: Transfer charger 23.24.25: Cleaner 26: Conveyance belt 39: Transport means 44: Lifting means 56: Fixing means Agent Patent attorney Akira Kurahashi □Figure 7Figure 9

Claims (1)

[Scope of Claims] 1) A conveying means for conveying a transfer material to the image forming station in order to transfer the image formed at the image forming station, and the conveying means is spaced apart from the image forming station. 1. An image forming apparatus, comprising: an elevating means for moving the image forming station to a certain position, and the elevating means is operated in accordance with an image forming operation state to bring the conveying means into contact with or away from an image forming station. 2) When bringing the conveying means into contact with the image forming station from a state in which the conveying means is retracted to a position apart from the image forming station, the image forming station is first cleaned, and after the cleaning operation is completed, the conveying means is moved up and down. Device according to claim 1, characterized in that the actuation of the means is carried out. 3) The apparatus according to claim 1, wherein the operation of the elevating means is performed based on a transfer material conveyance failure signal. 4) The device according to claim 1, wherein the lifting means is operated based on an opening/closing signal of an exterior door of the device. 5) The device according to claim 1, wherein the operation of the elevating means is stopped by an opening signal of an exterior door of the device. 6) The apparatus according to claim 1, wherein a plurality of positions of the conveying means are set apart from the image forming station. 7) The apparatus according to claim 1, wherein the elevating means is operated during the image forming operation based on an information signal indicating the type of transfer material, and the conveying speed of the conveying means is changed. 8) The apparatus according to any one of claims 1 to 7, wherein a plurality of image forming stations are provided.