JP2003295700A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide an image forming apparatus in which a plurality of different fixing speeds are set in accordance with the type of recording material, when an image is continuously formed on two different types of recording material. Provided is an image forming apparatus capable of shortening an image forming time. SOLUTION: When image formation is continuously performed on different types of paper and an OHT, of the paper and the OHT, a paper corresponding to a high fixing speed is set to a preceding recording material, and an OHT corresponding to a slow fixing speed is set to a subsequent recording material. As a recording material, the transfer device 5 includes paper and OH
After the T is carried on the transfer drum 5a, the paper is separated from the transfer drum 5a prior to the OHT, and a transfer process for the OHT is performed before the fixing of the paper by the fixing unit 9 is completed.
The fixing device 9 performs a fixing process in the order of the paper and the OHT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine of an electrophotographic type or an electrostatic recording type, a laser beam printer, a facsimile or the like.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine such as an electrophotographic system or an electrostatic recording system, a laser beam printer or a facsimile, a latent image carrier for carrying a latent image and the latent image carrier. Developing means for applying a developer to the body to convert the latent image into a developer image, transfer means for transferring the developer image from the latent image carrier to a recording material as an unfixed image, and the unfixed image An image forming apparatus is known in which a fixing means for fixing the recording material to the recording material by heating the recording material is set, and the fixing means has a plurality of different fixing speeds set according to the type of the recording material.

In such an image forming apparatus, for example, the feeding of the recording material is started by the generation of the image forming start signal, and the latent image carrier is formed on the latent image carrier based on the image signal from the personal computer and the image information such as the original. A series of operations in which a latent image is formed, a developing process is performed by the developing unit, a transfer process is performed by the transfer unit, and a fixing process is performed by the fixing unit, and the recording material after the fixing process is discharged outside the image forming apparatus. (Hereinafter referred to as a job) is executed.

Further, in such an image forming apparatus, two recording materials of different types, for example, paper or a transparency sheet for an overhead projector (hereinafter referred to as OH) are used.
(T) is used.

When an image is formed on paper, the fixing means is adapted to perform the fixing process at a fixing speed of, for example, 200 mm / sec.

On the other hand, when an image is formed on the OHT, the fixing means is used at a lower speed than the case of forming an image on paper, for example, 7 in order to improve the transparency of the image.
The fixing is performed at a fixing speed of 5 mm / sec. As a result, the toner is transparent, and the overhead projection device (hereinafter referred to as OHP) OH
When projecting an image on T, the light emission improves.

The fixing speed of the fixing means is generally the same as the conveying speed of the recording material before fixing. This is to prevent the recording material from forming a loop between the transfer means and the fixing means even in the case where the distance between the transfer means and the fixing means is short due to downsizing of the apparatus in recent years.

[0008]

In recent years, when forming an image on an OHT, the same image information (original in the case of a copying machine, image signal from a personal computer in the case of a printer) is used.
There is a demand for continuous image formation (hereinafter, also referred to as center insertion) in one job on both OHT and paper.

Therefore, conventionally, when one job is started, an image is first formed on a sheet as a preceding recording material, the sheet is fixed and discharged to the outside of the apparatus, and then a succeeding recording material is formed. An image was formed by feeding the OHT. This makes it possible to automatically and continuously form images on a plurality of recording materials having different fixing speeds in one job.

However, in the prior art, as described above, although it is possible to automatically and continuously form images on a plurality of recording materials having different fixing speeds in one job, it takes a long time to form an image. It had the drawback that it would end up.

Therefore, according to the present invention, in the image forming apparatus in which a plurality of fixing speeds different from each other are set in correspondence with the kinds of recording materials, when the images are continuously formed on the two different kinds of recording materials. An object of the present invention is to provide an image forming apparatus capable of shortening the image forming time.

[0012]

According to the present application, the above object is to provide a latent image bearing member carrying a latent image, and to apply the developer to the latent image bearing member to form the latent image with the developer image. Developing means, a transfer means for transferring the developer image from the latent image carrier to the recording material as an unfixed image, and a fixing means for heating the unfixed image to fix it on the recording material. ,
In the image forming apparatus in which a plurality of different fixing speeds are set according to the type of recording material, the fixing means is used when the image formation is continuously performed on two recording materials of different types. Of the two recording materials, the recording material corresponding to the faster fixing speed is the preceding recording material, and the recording material corresponding to the lower fixing speed is the trailing recording material, and the transfer means is the trailing material before the fixing of the preceding recording material by the fixing means is completed. This is accomplished by the second invention in which the transfer process is started on the recording material, and the fixing means performs the fixing process on the preceding recording material and the following recording material in this order.

According to the present application, in the first aspect of the present invention, the transfer means has a recording material carrier capable of carrying a plurality of recording materials, and the recording material carrier is of a type. When images are continuously formed on two different recording materials, the preceding recording material is carried before the succeeding recording material after carrying the preceding recording material and the following recording material. It is also achieved by the second invention of being separated from.

Further, according to the present application, in the second aspect of the present invention, the transfer means can switch from the fixing speed for the preceding recording material to the fixing speed for the following recording material by the fixing means. It is also achieved by the third invention in which the succeeding recording material is separated from the recording material carrier after being performed.

According to the present application, in the first aspect of the present invention, the transfer means has a developer image carrier capable of carrying a developer image corresponding to each of a plurality of recording materials. In the case of continuously forming images on two recording materials of different types, the developer image bearing member carries a developer image for the preceding recording material and a developer image for the following recording material. The present invention is also achieved by the fourth invention in which the preceding recording material receives the transfer of the developer image prior to the succeeding recording material.

Further, according to the present application, in the above-mentioned object, in any of the first to fourth inventions, the latent image carrier, the developing means and the transfer means form a color image on a recording material. It is also achieved by the fifth invention that is configured as described above.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described.

FIG. 1 is a sectional view showing the schematic arrangement of a color image forming apparatus as an example of the image forming apparatus according to this embodiment.

The color image forming apparatus shown in FIG. 1 is provided with a digital color image reader unit (hereinafter referred to as a reader unit) I on its upper portion and a digital color image printer unit (hereinafter referred to as a printer unit) at its lower portion. II is provided.

In the reader unit I, when a copy button (not shown) is pressed to generate an image formation start signal, the original 30 placed on the original glass 31 is exposed and scanned by the exposure lamp 32. The reflected light image obtained thereby is condensed by the lens 33 on the full color sensor 34, and a color separated image signal is obtained. The color-separated image signal is amplified by an amplifier circuit (not shown), subjected to predetermined processing by a video processing unit (not shown), and sent to the printer unit II.

In the printer section II, the photosensitive drum 1 serving as a latent image carrier is a large-diameter photosensitive drum having a diameter of 18 mm in this example, and is rotatably supported in the direction of arrow A in FIG. Around the photosensitive drum 1, a pre-exposure lamp 11 for initializing the charging of the surface of the photosensitive drum 1, a charger 2 (corona charger in this example) for uniformly charging the surface of the photosensitive drum 1, An image exposure unit 3 that forms an electrostatic latent image on the body drum 1 by an exposure process according to image information, a potential sensor 12 that detects the potential of the surface of the photoconductor drum 1, and an electrostatic charge formed on the photoconductor drum 1. Developing devices 4M, 4C, 4 as developing means for forming a latent image into a toner image by toner as a developer
Y, 4K, a photodetector 13 for detecting the amount of toner on the photoconductor drum 1, a transfer device 5 including a transfer drum 5a as a recording material carrier for transferring the toner image onto the recording material, and a photoconductor drum. A cleaner 6 and the like for removing the toner remaining on the sheet 1 are provided respectively.

In this example, the image exposure means 3 is composed of a polygon mirror 3a, a lens 3b, a mirror 3c, etc., and a laser output section (in accordance with the color-separated color image signal from the reader section I). The laser light E modulated and output by the not-shown) is reflected by the polygon mirror 3a, projected onto the surface of the photoconductor drum 1 by the lens 3b and the mirror 3c, and an electrostatic latent image corresponding to a color image signal of each color. To form.

At the time of image formation in the printer section II, the photosensitive drum 1 is rotated in the direction A in FIG. 1 at a peripheral speed of 200 mm / s, and the surface of the photosensitive drum 1 is first neutralized by the pre-exposure lamp 11. It is initialized. Next, the surface of the photosensitive drum 1 is uniformly charged by the charger 2, and the laser light E corresponding to the color-separated image signals of the respective colors is sequentially irradiated by the image exposure means 3 to electrostatically discharge in a predetermined color order. A latent image is formed.

Next, the developing units 4M, 4C, 4Y and 4K are
A predetermined development order for each color of magenta (M), cyan (C), yellow (Y), and black (K) (in this example, M, C,
The latent image on the photoconductor drum 1 is developed by operating in the order of Y and K), and a toner image based on resin is sequentially formed on the photoconductor drum 1. Here, the developing devices 4M, 4C, 4Y, 4
K is set so that the developing devices for the colors corresponding to the latent images on the photoconductor drum 1 can alternatively approach the photoconductor drum 1 to perform the developing operation by the operation of the eccentric cams 24M, 24C, 24Y, and 24K. Has become.

On the other hand, recording material cassettes 7a, 7b, 7c,
Alternatively, the recording material P fed from a manual tray (not shown) by a transport system including a pickup roller, a paper feed guide, a paper feed roller (none of which are shown), etc. is synchronized with a predetermined timing. It is conveyed to the transfer device 5.

In this example, the transfer device 5 includes a transfer drum 5a having a diameter of 180 mm as a recording material carrier, a transfer charger 5b for transferring the toner image on the photosensitive drum 1 to the recording material, and a recording material. The transfer drum 5a has a suction corona charger 5c, a suction roller 5g, an inner corona charger 5d, and an outer corona charger 5e. The transfer drum 5a is rotatably supported, and a recording material carrying sheet 5f made of a dielectric material is integrally stretched in a cylindrical shape to form a recording material carrying surface.

In the transfer device 5, two sheets are used for a recording material of A4 size or the like, and one sheet is used for a recording material of A3 size or the like.
A sheet of recording material is carried on the transfer drum 5a. As described above, when two recording materials are carried on the transfer drum 5a to form an image, the photosensitive drum 1 is continuously irradiated with the laser beam E in accordance with the same image signal and is developed, Continuously transfer color toner images from the photosensitive drum 1 to the transfer drum 5
It is performed by transferring the recording material on a. A dielectric sheet such as a polyester film is used as the recording material carrying sheet 5f.

Further, as shown in FIG. 2, the transfer device 5 has a connecting plate 5k for connecting the ring portions at both ends in the axial direction of the transfer drum 5a, and the recording material is substantially symmetrical with respect to the connecting plate 5k. Can be carried on the peripheral surface of the transfer drum 5a.
That is, when two recording materials such as A4 size are carried on the recording material carrying sheet 5f, as shown in FIG. 3, the two recording materials PA and PB sandwich the connecting plate 5k to sandwich the recording material carrying sheet. It is carried substantially uniformly on 5f. This recording material is sent from the recording material cassettes 7b and 7c as described above, and is carried on PB, PA and the recording material carrying sheet 5f in order.
In addition, hereinafter, regarding the surface on the recording material carrying sheet 5f, PB
The side is also referred to as the B surface, and the PA side is also referred to as the A surface.

The transfer drum 5a is rotated in the direction of the arrow in FIG. 1 in synchronization with the rotation of the photosensitive drum 1. The magenta toner image developed by the magenta developing device 4M is transferred onto the recording material carried on the recording material carrying sheet 5f by the transfer charging device 5b at the transfer portion between the transfer drum 5a and the photosensitive drum 1. Transcribed. After that, the transfer drum 5a is continuously rotated and is ready for transfer of an image of the next color (for example, cyan in this embodiment).

After the transfer of the toner image onto the recording material, the photoconductor drum 1 is cleaned by the cleaner 6 to remove adhering substances such as residual toner on the photoconductor drum 1.
Then, the photoconductor drum 1 is uniformly charged again by the charger 2, and is subjected to the same image exposure as described above by the laser light modulated according to the next cyan image signal.

The latent image corresponding to cyan is developed by the cyan developing device 4C and visualized as a cyan toner image. This cyan toner image is transferred onto the recording material carried on the recording material carrying sheet 5f by the transfer charger 5b at the above-mentioned transfer portion so as to be superimposed on the above-mentioned magenta toner image. After that, the transfer drum 5a is continuously rotated and is ready for transfer of an image of the next color (for example, yellow in this embodiment).

Subsequently, when the yellow and black images are formed and transferred by the same process as described above and the superimposing transfer of the toner images of four colors is completed, the recording material is charged with a separating charger 5h by AC corona discharge. Is discharged by. Next, the recording material is separated and pushed up by the roller 8b and the separation claw 8a.
The PB and PA are sequentially separated from the transfer drum 5a by the above action, are conveyed to a fixing device (heat roller fixing device in this example) 9 as a fixing means, undergo a fixing process, and are discharged onto a tray 10.

Incidentally, in the present embodiment, when the recording material is separated from the transfer drum 5a, as shown in FIG. 4, a conventionally known AC charge removal is applied by a separation charger 5h to scatter toner. It is intended to prevent peeling electrification and the like.

Further, in the present embodiment, in order to prevent the scattering of powder on the recording material carrying sheet 5f of the transfer drum 5a and the adhesion of oil on the recording material, the recording material carrying sheet 5f is used.
The recording material carrying sheet 5f is cleaned by the action of the fur brush 14 facing the backup brush 15 via the oil removing roller 16 facing the backup brush 17 via the recording material carrying sheet 5f. There is. Such cleaning is performed before or after image formation, and at any time when a jam (paper jam) occurs.

As shown in FIG. 5, the fixing device 9 includes a fixing roller 51 that is rotatably disposed, a pressure roller 52 that rotates while being in pressure contact with the fixing roller 51, and a release agent applying device 53. And a roller cleaning device 54.

Inside the fixing roller 51 and the pressure roller 52, heaters 56 and 57 (600 W in this example) such as halogen lamps are provided. Further, thermistors 58 and 59 are arranged in contact with the surfaces of the fixing roller 51 and the pressure roller 52, respectively. In this embodiment, the surface temperature of the fixing roller 51 and the pressure roller 52 is controlled by controlling the voltage to the heaters 56 and 57 by a temperature control circuit (not shown) based on the detection signals from the thermistors 58 and 59. It is designed to be maintained at 170 ° C.

The fixing roller 51 is, for example, an HTV (high temperature vulcanization) type silicone rubber 123 as a lower layer, a fluorine rubber 125 having a thickness of 45 μm as an intermediate layer, and an upper layer as an upper layer on a core metal 122 made of aluminum having a thickness of 6 mm. Thickness 200
An elastic layer composed of three layers of highly releasable silicone rubber 124 having a thickness of μm is formed.

Like the fixing roller 51, the pressure roller 52 has an elastic layer composed of three layers of a lower layer 128, an intermediate layer 129, and an upper layer 127 formed on a core metal 126 made of aluminum having a thickness of 6 mm, for example. There is. In the present embodiment, the total thickness of this elastic layer is 1.8 mm.

A roller cleaning device 54 and a release agent applying device 53 are provided around the fixing roller 51, and the roller cleaning device 54 cleans the toner t or the like offset on the fixing roller 51. At the same time, the release agent applying device 53 applies a release agent, such as silicone oil, to the fixing roller 51 to facilitate separation of the recording material P from the fixing roller 51 and prevent toner offset. ing.

The roller cleaning device 54 includes a cleaning web 54a made of a band-shaped heat-resistant nonwoven fabric, a pressing roller 54b for pressing the cleaning web 54a against the fixing roller 51, and a new cleaning web 54a.
It is configured to have an unwinding roller 54c that unwinds the surface, and a winding roller 54d that gradually winds up the surface of the cleaning web 54a whose cleaning ability has deteriorated due to the adhesion of toner or the like. This roller cleaning device 54
In order to prevent detection failure of the thermistor 58 due to adhesion of offset toner to the thermistor 58,
On the other hand, it is provided on the upstream side in the rotation direction of the fixing roller 51.

The mold release agent applying device 53 includes an oil tank 53a containing a mold release agent such as silicone oil, pumping rollers 53b and 53c for pumping oil as a mold release agent from the oil tank 53a, and pumping rollers 53b and 53c. Applying roller 53d for applying the oil from the fixing roller 51 to the fixing roller 51
And a blade 53e that regulates the amount of oil applied on the applying roller 53d to a predetermined amount. The release agent applying device 53 is arranged downstream of the thermistor 58 in the rotational direction of the fixing roller 51, in order to apply the oil uniformly to the fixing roller 51. still,
The application roller 53d is a rotatable roller in which the surface of sponge rubber is coated with silicon rubber, and contacts the fixing roller 51 as necessary to apply oil to the fixing roller 51.

When the recording material P is conveyed to the above-mentioned fixing device 9, the fixing roller 51 and the pressure roller 52 rotate at a constant speed, and in the case of general paper, the recording material P in the main body of the image forming apparatus. It is rotated at a peripheral speed of 200 mm / s which is the same as the transport speed. At this time, silicone oil is applied to the surface of the fixing roller 51.

When the recording material P passes between the fixing roller 51 and the pressure roller 52, the recording material P is pressed and heated at a substantially constant pressure and temperature from both front and back surfaces, and is not yet fixed on the recording material P. The toner image is melted and fixed, and a full-color image is formed on the recording material P.

The recording material P on which the image has been fixed is separated from the pressure roller 52 by the lower separating claw 68 and is discharged to the outside of the image forming apparatus.

Regarding the toner in this embodiment, as described above, in this type of image forming apparatus, the color toner image is formed on the recording material P by the multi-color toner t in two to four superposed layers. Therefore, the toner to be used is required to have good meltability and color mixing property when heat is applied, and a sharp melt toner having a low softening point and a low melt viscosity is used.

In the image forming apparatus as described above, in the present embodiment, the recording material is paper, especially general paper (hereinafter,
The fixing of plain paper (for example, 105 g / cm ² or less) is performed at 200 mm / sec, which is almost the same as the peripheral speed of the transfer drum 5a. This is because the transfer drum 5 a
In a device in which the distance between the recording material separating position and the nip formed by the pressure contact of the fixing roller 51 and the pressure roller 52 is short, the peripheral speed of the fixing roller 51 and the peripheral speed of the transfer drum 5a are matched to each other. This is to prevent the recording material from forming a loop between the above.

On the other hand, when an image is formed on a transparency sheet for an overhead projector (hereinafter referred to as OHT), fixing is performed at a low speed, for example, 75 mm / sec in order to improve the image transparency as its application. ing. As a result, the toner is transparent and the overhead projection device (hereinafter referred to as OH
When the image is projected on the OHT at (P), the light emission is improved.

Further, in the case of image formation on the OHT, since fixing is performed at a low speed as described above, after the transfer of the toner images of M, C, Y and K from the transfer drum 5a to the OHT, the OHT is performed.
Is not immediately separated from the transfer drum 5a, is switched to a low speed while being carried on the transfer drum 5a, and is separated from the transfer drum 5a after the transfer drum 5a is rotated once. As a result, the fixing speed of the fixing device at a low speed matches the peripheral speed of the transfer drum 5a, and the OHT is prevented from forming a loop between transfer and fixing.

Here, the operation of the image forming apparatus of this embodiment at the time of continuous image formation on a plurality of recording materials of different types will be described. In this embodiment, a case will be described in which continuous image formation (hereinafter referred to as OHT insertion) is performed on one sheet of paper (A4 size) and OHT (A4 size) based on the same image information.

In the present embodiment, in the case of OHT insertion, when the image formation start signal is generated, the paper is used as the preceding recording material and the OHT is used as the following recording material.
The toner images are simultaneously carried on the transfer drum 5 a and receive the toner image transferred from the photosensitive drum 1. That is, with respect to the transfer drum 5a, first, the paper is carried on the B side, then the OHT is carried on the A side, and then the paper and the OHT are carried on the transfer drum 5a from the photosensitive drum 1. And the OHT, respectively, to transfer the toner image. At this time, the transfer charger 5b switches the transfer conditions suitable for the paper and the OHT to transfer the toner image.

First, the paper on which the toner image has been transferred is separated from the surface B of the transfer drum 5a and subjected to a fixing process by the fixing device 9. At this time, since the fixing speed of the fixing device 9 on the paper is 200 mm / sec, which is the same as the peripheral speed of the transfer drum 5a, the paper is smoothly heat-fixed and discharged to the outside of the machine.

Then, subsequently, the OHT to which the toner image has been transferred is separated from the surface A of the transfer drum 5a and subjected to a fixing process by the fixing device 9. At this time, when the fixing process of the preceding paper is completed, the fixing speed of the fixing device 9 (the peripheral speed of the fixing roller 51) and the peripheral speed of the transfer drum 5a are reduced to 75 mm / sec for the low speed OHT. As a result, the OHT is fixed to the OHT at a fixing speed suitable for the OHT and does not form a loop between the transfer drum 5a and the fixing device 9.

Therefore, as described above, in the present embodiment, the image formation is performed on the paper and the OHT in separate jobs in the related art, whereas the image formation is performed on the paper and the OHT in the same job. Therefore, it is possible to reduce the overall image formation time from 50 seconds (total of 20 seconds required for image formation on paper and 30 seconds required for OHT image formation) to 3 seconds.
It became possible to shorten to 0 seconds.

Further, of the paper and the OHT, the paper corresponding to the high fixing speed is subjected to the image forming processing first, so that the subsequent OH
It became possible to satisfactorily perform the image formation of the OHT insertion in a short time without T catching the paper and disturbing the image.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The same components as those of the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, in the case of the OHT insertion, the steps up to carrying the paper on the B side and the OHT on the A side of the transfer drum 5a are the same as those in the first embodiment described above.
The timing for separating T from the transfer drum 5a is different from that in the first embodiment.

That is, when separating the paper and the OHT from the transfer drum 5a, first, the paper is separated from the B side of the transfer drum 5a, and the paper is fixed at a fixing speed of 2 by the fixing device 9.
After fixing at 00 mm / sec, the OHT is rotated without being separated from the transfer drum 5a immediately while being carried on the transfer drum 5a (hereinafter referred to as dummy rotation).

During the dummy rotation of the OHT, the OHT
After the trailing end of the rotation direction of No. 2 passes the separation point by the separation claw 8a, the fixing speed is set to a low fixing speed 7 corresponding to OHT.
Switch to 5 mm / sec to slow down. After that, the OHT is separated from the transfer drum 5a after the transfer drum 5a makes one round while carrying the OHT.
It is fixed by.

Thus, in the present embodiment, in the first embodiment described above, the fixing speed and the transfer drum 5 during the separation of the OHT from the transfer drum 5a and the transfer of the toner image to the OHT are performed.
The peripheral speed of a is from 200 mm / sec to 75 mm / sec
Although it was difficult to set each operating condition, it became possible to form an OHT image in a more suitable manner and in a shorter time than before.

However, in the present embodiment, since the OHT is dummy-rotated on the transfer drum 5a, the total time required for image formation of the OHT insertion is longer than that in the first embodiment described above and is about 35. Will end up. However, it is useful in that an OHT insertion image can be formed in a shorter time than in the conventional case, and further, the above-mentioned respective operating conditions can be easily set.

(Third Embodiment) Next, a third embodiment of the present invention will be described. The same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The present embodiment is an example in which the present invention is applied to a 4-drum type image forming apparatus as shown in FIG.

The image forming apparatus shown in FIG. 6 includes a photosensitive drum 1 serving as a latent image carrier, a charging device 2, a developing device 4 serving as developing means, a transfer device 5 ′ serving as transfer means, and a fixing device serving as fixing means. 9 and 9.

In such an image forming apparatus, the charger 2
A latent image is formed for each color by the laser light E on the surface of the photosensitive drum 1 that is uniformly charged by the laser beam E. Each latent image is
Each developing device of the developing device 4 applies toner, which is a developer, to the photosensitive drum 1 to visualize the toner image.

The toner image of each color is transferred from the photosensitive drum 1 to the transfer device 5'by the transfer charger 5b of the transfer device 5 '.
Are sequentially transferred as an unfixed image onto the recording material P on the transfer belt 5T.

The recording material P carrying the unfixed image formed by superposing the toner images of the respective colors is separated from the transfer belt 5T,
The unfixed image is heated by the fixing device 9 to be fixed on the recording material P. Here, the fixing device 9
A plurality of different fixing speeds are set according to the type of recording material. In the present embodiment, similar to the above-described first embodiment, when the recording material is paper, 200 mm / sec, OHT,
In this case, the fixing speed is set to 75 mm / sec.

Conventionally, in the above-mentioned image forming apparatus, when the image formation of the OHT insertion is performed, since the feeding of the OHT is started after the fixing processing of the paper, it takes a long time as the entire image forming time. Was.

In view of this, in the present embodiment, when the image formation of the OHT insert is performed, the paper is first carried on the transfer belt 5T, and then the OHT is carried, and then the paper and the O
With the HT carried on the transfer belt 5T, the toner images are transferred from the photosensitive drum 1 to the paper and the OHT, respectively. As a result, it becomes possible to form an image with the OHT insertion in a shorter time than in the conventional case where the OHT is fed after the paper is fixed and carried on the transfer belt 5T to perform the OHT insertion. It is possible to obtain the same effect as that of the second embodiment.

That is, in the present embodiment, after the paper is completely separated from the transfer belt 5T, the peripheral speed of the transfer belt 5T is reduced to 75 mm / sec, and the OH is maintained at that speed.
Since T is conveyed to the fixing device 9, it is possible to form a suitable image in a short time without the OHT forming a loop between the transfer belt 5T and the fixing device 9 or the OHT catching up with the preceding paper. became.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. The same components as those in the first embodiment or the third embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The present embodiment is an example in which the present invention is applied to an image forming apparatus using an intermediate transfer member as shown in FIG.

In the image forming apparatus shown in FIG. 7, a latent image is formed for each color by the laser beam E on the surface of the photosensitive drum 1 uniformly charged by the charger 2. Each latent image is visualized as a toner image by each developing device of the developing device 4 applying toner as a developer to the photosensitive drum 1.

The toner images of the respective colors are transferred from the photosensitive drum 1 onto the intermediate transfer member 5T 'of the transfer device 5''serving as the transfer means, and once carried on the intermediate transfer member 5T', and then transferred to the transfer device 5. The transfer charger 5b for the intermediate transfer body 5T
′ ′ Is collectively transferred to the recording material P as an unfixed image. At this time, for example, two sheets of A4 size images can be formed on the intermediate transfer member 5T 'on the other hand.

The recording material P carrying the unfixed image formed by superposing the toner images of the respective colors is fixed on the recording material P by heating the unfixed image by the fixing device 9.
Here, in the fixing device 9, a plurality of different fixing speeds are set according to the type of recording material. In the present embodiment, similar to the above-described first embodiment, when the recording material is paper, 20
The fixing speed is set to 0 mm / sec and 75 mm / sec for OHT.

Conventionally, in the image forming apparatus as described above, when the image formation of the OHT insertion is performed, since the feeding of the OHT is started after the fixing processing of the paper, it takes a long time as the entire image forming time. Was.

In view of this, in the present embodiment, when an image is formed by OHT insertion, a toner image for paper is first carried on one half of the intermediate transfer member 5T ', and then the other surface is used for OHT. After the toner image is carried, the toner images are collectively transferred from the intermediate transfer body 5T 'to the paper and the OHT.

That is, in the present embodiment, from the state in which the toner image for paper and the toner image for OHT are carried on the intermediate transfer member 5T ', first, the above-mentioned toner image for paper is placed on the paper. Are collectively transferred from the intermediate transfer member 5T ′ and are fixed by the fixing device 9, and then the above O is continuously transferred to the OHT.
The toner image for HT is collectively transferred from the intermediate transfer body 5T '. At this time, the fixing speed of the fixing device 9 and the peripheral speed of the intermediate transfer member 5T ′ are switched to a low speed of 75 mm / sec at the timing when the preceding fixing process of the paper by the fixing device 9 is completed.

As a result, also in this embodiment, the same effect as that of the above-described third embodiment can be obtained.

Although the embodiments of the present invention have been described above, as described above, the present invention is completely new in that recording materials of different materials such as paper and OHT can be image-formed simultaneously (in one job). It was made under the idea. That is, when two recording materials made of resin such as OHT, which has a low fixing speed in the past, are carried on the transfer drum,
It is known that the number of recording materials supported on the transfer drum is limited to one because the following recording material catches up with the preceding recording material in the conveying path in the image forming apparatus. It is very different from this.

In the first to fourth embodiments described above, the fixing speed on paper is set to 200 mm / se.
The fixing speed for c and OHT is set to 75 mm / sec, but the present invention is not limited to this, and can be appropriately set depending on the characteristics of the toner, the device configuration, and the like.

Further, in the first to fourth embodiments, an example of forming an image according to the image information of the original on the original table has been described, but the present invention is not limited to this, and a personal computer It is also applicable to an apparatus that forms an image in accordance with image information from the above.

Further, in the first to fourth embodiments, the paper is placed downward in the case of the image formation of the OHT insert.
The OHTs are stacked on the discharge tray in the order of upper side and discharged, but if you want to stack the OHT on the lower side and the paper on the upper side,
After the paper is discharged, the upper and lower sides may be replaced by a conventionally known buffer path or the like.

Further, in the first to fourth embodiments, the total image forming time in the case of the image formation of the OHT insertion is 30 seconds, 35 seconds, etc., but this depends on the configuration of the apparatus. However, the rate of reduction and the like in comparison with the conventional one is not limited to this.

[0085]

As described above, according to the first invention of the present application, when images are continuously formed on two recording materials of different types, one of the two recording materials The recording material corresponding to the fast fixing speed is the preceding recording material, and the recording material corresponding to the slow fixing speed is the trailing recording material, and the transfer unit transfers the trailing recording material before the fixing of the preceding recording material by the fixing unit. Since the fixing means performs the fixing process in the order of the preceding recording material and the following recording material, a plurality of different fixing speeds are set according to the type of recording material. In the image forming apparatus, it is possible to shorten the image forming time when continuously forming images on two recording materials of different types.

According to the second invention of the present application,
When images are continuously formed on two recording materials of different types, the recording material corresponding to the faster fixing speed is the preceding recording material and the recording material corresponding to the lower fixing speed is the latter of the two recording materials. As a line recording material, the transfer means, after the recording material carrier carries the preceding recording material and the succeeding recording material, the preceding recording material is separated from the recording material carrier prior to the succeeding recording material, Before the fixing of the preceding recording material by the fixing means, the transfer processing to the succeeding recording material is started, and the fixing means performs the fixing processing in the order of the preceding recording material and the succeeding recording material. In an image forming apparatus in which a plurality of different fixing speeds are set according to the type of recording material, it is possible to shorten the image forming time when continuously forming images on two recording materials of different types. You can

Further, according to the third invention of the present application, in the case where images are continuously formed on two recording materials of different types, the high fixing speed of the two recording materials is supported. The recording material is the preceding recording material, the recording material corresponding to the slow fixing speed is the following recording material, and the transfer means is such that after the preceding recording material and the following recording material are carried by the recording material carrier, The trailing recording material is separated from the recording material carrier before the trailing recording material, and is switched from the fixing speed for the leading recording material to the fixing speed for the trailing recording material by the fixing means. Is separated from the recording material carrier, and the transfer processing to the succeeding recording material is started before the fixing of the preceding recording material by the fixing means is completed, and the fixing means fixes the preceding recording material and the succeeding recording material in this order. The recording material seed In the image forming apparatus in which a plurality of fixing speed is set different corresponding to, it is possible to shorten the image forming time for continuous image formation with respect to different types of two recording materials.

According to the fourth invention of the present application,
When images are continuously formed on two recording materials of different types, the recording material corresponding to the faster fixing speed is the preceding recording material and the recording material corresponding to the lower fixing speed is the latter of the two recording materials. In the transfer means, the developer image bearing member carries a developer image for the preceding recording material and a developer image for the following recording material, and the preceding recording material is the following recording material. Before the fixing of the preceding recording material by the fixing means is completed, the transfer processing for the succeeding recording material is started before the fixing image of the preceding recording material and the following recording material is transferred. Since the fixing process is performed in order, in an image forming apparatus in which a plurality of different fixing speeds are set according to the type of recording material, image formation is continuously performed on two recording materials of different types. It is possible to shorten the image forming time when performing

Further, according to the fifth invention of the present application, when a color image is continuously formed on two recording materials of different types, it corresponds to the faster fixing speed of the two recording materials. The recording material to be used is the preceding recording material, and the recording material corresponding to the slow fixing speed is the succeeding recording material, and the transfer means starts the transfer processing to the succeeding recording material before the fixing of the preceding recording material by the fixing means is completed. Since the fixing unit is configured to perform the fixing process in the order of the preceding recording material and the following recording material, in the image forming apparatus in which a plurality of different fixing speeds are set according to the type of recording material, In the case of forming a color image with a long image forming time, it is possible to reduce the image forming time when continuously forming images on two recording materials of different types, and it is possible to reduce the image forming time. It is especially remarkable.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a recording material carrier provided in the image forming apparatus of FIG.

FIG. 3 is a diagram for explaining a relationship between a recording material carrier and a recording material provided in the image forming apparatus of FIG.

FIG. 4 is a diagram for explaining separation of the recording material from the recording material carrier according to the first embodiment of the present invention.

5 is a sectional view showing a schematic configuration of a fixing unit provided in the image forming apparatus of FIG.

FIG. 6 is a sectional view showing a schematic configuration of an image forming apparatus according to a third embodiment of the present invention.

FIG. 7 is a sectional view showing a schematic configuration of an image forming apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 Photoconductor drum (latent image carrier) 4 Developing device (developing means) 4M, 4C, 4Y, 4K developing device (developing means) 5 Transfer device (transfer means) 5'transfer device (transfer means) 5 ″ Transfer device (transfer means) 5a Transfer drum (recording material carrier) 5T transfer belt (recording material carrier) 5T 'Intermediate transfer body (recording material carrier) 9 Fixing device (fixing means) P recording material PA, PB recording material (subsequent recording material, preceding recording material) t Toner (developer)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H027 DC02 ED17 ED25 EE03 FA28                       FA30                 2H033 AA11 AA20 AA45 BA59 CA09                       CA20 CA36 CA37                 2H300 EB02 EB04 EB08 EB12 EC02                       EC04 ED05 ED12 EF02 EF03                       EF05 EF09 EF13 EF20 EG03                       EH15 EH16 EJ09 EJ15 EK03                       EK06 EK07 EK09 EK10 EL05                       FF12 GG01 GG02 GG03 GG07                       GG11 GG31 GG47 HH16 HH18                       HH19 QQ12 QQ19 QQ22 QQ32

Claims (5)

[Claims] 1. A latent image bearing member carrying a latent image, developing means for applying a developer to the latent image bearing member to convert the latent image into a developer image, and the latent image carrying the latent image. The recording medium is provided with a transfer unit that transfers an unfixed image from the carrier to the recording material, and a fixing unit that fixes the unfixed image on the recording material by heating, and the fixing unit corresponds to the type of the recording material. In an image forming apparatus in which a plurality of different fixing speeds are set, when images are continuously formed on two different kinds of recording materials, the recording material corresponding to the higher fixing speed among the two recording materials. Is a preceding recording material, and a recording material corresponding to a slow fixing speed is a succeeding recording material, and the transfer means starts the transfer process to the succeeding recording material before the fixing means finishes fixing the preceding recording material. Then, the preceding recording material and the following recording material are fixed in this order. An image forming apparatus, which is adapted to perform processing. 2. The transfer means has a recording material carrier capable of carrying a plurality of recording materials, and the recording material carrier is capable of continuously forming images on two recording materials of different types. In this case, after the preceding recording material and the succeeding recording material are carried, the preceding recording material is separated from the recording material carrier prior to the succeeding recording material. The image forming apparatus described. 3. The transfer means separates the trailing recording material from the recording material carrier after the fixing means switches the fixing speed for the preceding recording material to the fixing speed for the trailing recording material. Claim 2 which is adapted to be carried out.
The image forming apparatus according to item 1. 4. The transfer means has a developer image carrier capable of respectively carrying a developer image corresponding to a plurality of recording materials, and the developer image carrier is provided for two different kinds of recording materials. In the case of continuously forming images, after the developer image for the preceding recording material and the developer image for the following recording material are carried, the preceding recording material precedes the following recording material by the developer. The image forming apparatus according to claim 1, wherein the image forming apparatus is adapted to receive an image transfer. 5. The image according to claim 1, wherein the latent image carrier, the developing means and the transfer means are configured to form a color image on a recording material. Forming equipment.