JPH04122956A - Color image forming device - Google Patents

Abstract

PURPOSE:To thoroughly melt and mix overlapped toner and to form a color image having good saturation and with a well-balanced state in color by carrying a transfer material to a fixing device again after forming the image under an ordinary mode, and performing re-fixation. CONSTITUTION:A color image formed on the surface of an image carrier 30 is transferred on the transfer material fed from a paper feeding part D by a transfer device 40. After transfer, the transfer material is separated from the surface of a drum at a separation curve 43, and then, carried into the fixing device 45 through a carrying belt 44, and the paper is ejected after performing the fixation. And the transfer material P on which the fixation is performed once is placed lying between the notch part of a movable part 52 of a cassette 50 for performing the re-fixation and a fixing part 54. And the cassette 50 is set in a device main body by sliding a projecting part along guiding members 57 and 58 of the device main body. And furthermore, when a turning part is turned, the movable part 52 is turned, and then, the leading edge part of the transfer material P falls on a belt 44. Meanwhile, the carrying speed of the belt 44, the fixation speed of the device 45 is set to 1/n times of the speed at the time of the ordinary mode, and the fixation temperature is increased by 10 - 40 deg.C higher than the temperature in the case of the ordinary mode. And the leading edge of the transfer material P on the belt 44 is pulled out so that it may be carried to the device 45 and the re-fixation may be performed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color image forming method in which a toner image is formed on an image carrier by electrophotography and transferred onto a transfer material to obtain a color image. Regarding equipment.

In particular, the present invention relates to color image forming apparatuses such as printers, copiers, and facsimiles that can form color images with excellent color reproducibility on transfer materials such as OHP films.

[Conventional technology]

In conventional color image forming apparatuses, when forming color images on transfer materials, especially cardboard and OHP films, in order to obtain excellent color reproducibility of color toner images,
Since it is necessary to almost completely dissolve the toner to eliminate unevenness on the surface of the toner layer and to make the surface smooth, color toner images have been fixed by changing the fixing conditions.

Methods for changing the fixing conditions include changing the fixing temperature and changing the fixing speed. The former method of changing the fixing temperature takes time to reach a predetermined temperature, offset is likely to occur due to temperature changes, and color reproducibility is insufficient just by increasing the temperature. There are other problems. On the other hand, the latter method of changing the fixing speed requires the distance from the transfer means to the fixing means to be longer than the transfer material, and also requires that the rear end of the previous transfer material and the front end of the subsequent transfer material be There is a problem in that the fixing speed can only be slowed down to the extent that it does not become 1.

In any case, it is not possible to obtain a color image with excellent color reproducibility by forming an image by changing the fixing temperature or fixing speed.

Taking these problems into consideration, the applicant has proposed
No. 41767 discloses an image forming apparatus that can obtain a color image with excellent color reproducibility by transporting a transfer material once fixed by a transfer material transporting means to be fixed again. is suggesting.

[Problem that the invention seeks to solve]

However, in the image forming apparatus disclosed in the above-mentioned publication, the transfer material once fixed is conveyed to the re-fixing conveyance path by the guide claw, and then fixed again by the fixing means.
However, this method has the following drawbacks: the structure is complicated, and the device must also be larger.

The present invention has been made to solve the above-mentioned drawbacks.
SUMMARY OF THE INVENTION An object of the present invention is to provide a compact color image forming apparatus that is capable of re-fixing a transfer material once fixed using a fixing means of the main body, has a simple mechanism, and is compact. In addition, we aim to provide a color image forming apparatus equipped with a re-fixing mechanism that can improve gloss, light transmittance, and fixing performance when fixing of color images or OHP films is insufficient. be.

[Failure to solve the problem]

The above object includes a transfer means for transferring a toner image on a photoreceptor onto a transfer material, a conveyance means for conveying the transfer material to which the toner image has been transferred by the transfer means, and a transfer means for conveying the transfer material to which the toner image has been transferred by the transfer means; a fixing means for fixing the toner image on the transfer material;
The present invention further includes a removable transfer material storage means capable of storing the transfer material once fixed by the fixing means and feeding the transfer material to the fixing means in order to fix the transfer material again. This is achieved by a color image forming apparatus having the following characteristics.

[! l! Example]

Next, the present invention will be described based on an embodiment shown in the accompanying drawings.

FIG. 1 shows the main structure of a color copying machine which is a color image recording device. This color copying machine is composed of an image reading system A, a laser writing system B, and an image forming section C1 and a paper feeding section, and a color image is formed by the following process.

In the reading system A, the 12N documents placed on the document table 1 are illuminated by a halogen lamp J3 attached to a carriage 12 that slides in the horizontal direction. Mirrors 16 and 17 are attached to the movable mirror unit 15, which also slide in the horizontal direction, and in combination with the mirror 14 attached to the carriage J2, transmit the optical image of the document to the lens reading section 20. Derive.

The carriage J2 and the movable mirror unit 15 are driven via wires (both not shown) connected to a stepping motor, and are slid in the same direction at speeds of V and 172V, respectively.

The lens reading unit 20 includes a lens 21, a CCD 23 at an imaging position behind the lens 21, and a filter 22 in front of the lens 21 that is controlled by the CPU and moves in a direction perpendicular to the plane of the drawing. The filter 22 is used to separate colors when reading the original on the developing table 11, and includes a self-filter that passes red, green, and blue light, and a neutral filter that passes all three color lights. be. When developing with cyan (C) toner, a red filter is used.
The CPU issues a command so that the green filter is used for development with magenta (M) toner, or the blue filter is used for development with yellow (Y) toner, and the filter selection circuit sets the filter. Furthermore, a neutral filter is used for development with black (BK) toner.

The t two-color signal, which has been color-corrected according to the color of the toner, is input to the laser writing system unit B, which is an exposure means.

In the laser writing system unit B, a semiconductor laser (
The laser beam generated by the drive unit 31 (not shown)
The rotation operation is performed by the polygon mirror 32 rotated by the fθ lens 33 . The optical path is bent by a mirror 34 through a cylindrical lens 33', and the image carrier 30 is scanned over the circumferential surface of the image carrier 30, which has been uniformly charged to a predetermined charge by a charger 35, which is a charging means.

On the other hand, in the sub-scanning direction, an index provided at a specific position on the image carrier 30 is detected by a photosensor (none of which is shown), a print command signal is received, and an image signal is generated based on this detection or the command signal. modulation of the semiconductor laser is started, and the main scanning direction is determined. When scanning is started, the laser beam is detected by an index sensor (not shown) in the main scanning direction, and modulation of the semiconductor laser by the image signal of the first color is started based on the detected signal, The modulated laser beam scans the circumferential surface of the image carrier 30. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the image carrier 30 by main scanning by the laser beam and sub-scanning by the rotation of the image carrier 30. In this embodiment, this latent image is developed by, for example, a developing device 36Y loaded with yellow (Y) toner (developing medium) among a plurality of developing devices provided in parallel.
A toner image is formed on the drum surface. The obtained toner image, while being held on the drum surface, passes under a cleaning device 39, which is a cleaning means, which is spaced apart from the circumferential surface of the image carrier 30, and enters the next copy cycle.

That is, the image carrier 30 on which the yellow toner image is formed
is charged again by the charger 35, and then the second color signal output from the signal processing section is input to the laser writing system B, and is written on the drum surface in the same manner as the first color signal described above. is performed to form a latent image. The latent image is developed by a developer 36M loaded with a second color, for example, magenta (M) toner. This magenta (M) toner image is replaced by the already formed yellow (Y) toner image.
) formed in the presence of a toner image.

Similarly, the latent image formed by the third color image signal output from the signal processing section is developed by the developing device 36C containing cyan (C) toner, and a cyan (C) toner image is formed. The latent image formed by the image signal of the fourth color is developed in a developing device 368 containing blank (BK) toner, and the black (BK) toner image is superimposed on the drum surface to form a color toner image. It is formed on the surface of the image carrier 30.

These developing devices 36Y, 36M, 36C, 36
A direct current or even alternating current bias is applied to the BK developing sleeve, and reversal development (jumping development) is performed in a non-contact manner on the image carrier 30 whose base is grounded. Note that although either a one-component developer or a two-component developer can be used for this non-contact development, the development method using a two-component developer is superior in terms of development stability. Therefore, it is preferable in terms of color reproduction.

As described above, the color image formed on the surface of the image carrier 30 is fed from a paper feed section by a paper feed belt 41 to a transfer device 40 provided as a transfer means, and is synchronized with the color image by a timing roller 42. The image is transferred to the matching transfer material. The transfer device 40 performs transfer by applying a high-voltage power source having a polarity opposite to that of the toner. The transfer material on which the color image has been transferred is thus separated from the drum surface by the separation pole 43, conveyed to the fixing device 45 via the conveyor belt 44, where the image is fixed, and then discharged.

On the other hand, the blade 39A of the cleaning device 39 contacts the image carrier 30 from which the transfer material has been separated from the drum circumferential surface to remove the remaining toner. Introducing new color image formation processes.

Note that in the color copying machine configured as described above, the paper feed belt 41. Timing roller 42° image carrier 30. The transport speed of the transfer material by the transport belt 44 and the fixing speed of the fixing device 45 are both 120 mm/sec, and the fixing temperature of the fixing device 42 is 160°C.

Also, above the conveyor belt 44 of the above-mentioned color copying machine, a re-fixing case 50 is removably provided as transfer material storage means. As shown in FIG. 2, the re-fixing cassette 50 has a movable part 52 rotatably provided on a frame body 51, and has a movable part 52 integrally attached to both ends of the movable part 52 protruding from the frame body 51. A rotating member 53 that rotates in this manner is provided. Furthermore, a fixing portion 54 is fixed to the frame 51.

On the other hand, in order to attach and detach the re-fixing cassette 50, the re-fixing cassette 50 is provided with recesses 55 and 56 of different shapes, and the main body of the apparatus is provided with a guide having a protrusion corresponding to the recesses 55 and 56. Members 57, 58 are provided.

Next, using the color copying machine mentioned above, OHP film,
A case where a color image is formed on a transfer material such as cardboard will be explained.

First, an image is formed on a transfer material in the above-described normal mode, and the paper is ejected from the apparatus.

Then, the once-fixed transfer material P is transferred to the re-fixing cassette 5.
The rack is placed across the notch 52A provided in the movable part 52 of 0 and the fixed part 54. Then, the re-fixing cassette 50 is set in the apparatus main body, for example, from the front of the apparatus main body, with the recesses 55 and 56 aligned with guide members 57 and 58 provided on the apparatus main body. Furthermore, when the rotary portion 53 is rotated, the movable portion 52 rotates to convey and press the leading end of the transfer material P placed on the notch portion 52A (see FIG. 3).

By this pressing operation, as shown in FIG. 4, the OHP mode is input to the control means, drive motor speed control and fixing temperature control are output, and the conveying speed of the conveying belt 44 and the fixing speed of the fixing device 45 are set to the normal mode. At the same time, the fixing temperature of the fixing device 45 is increased by lO to 40°C compared to the normal mode, for example, from 160°C to 180°C. The temperature is controlled to increase.

Then, when the fixing temperature of the fixing device 45 rises to 180° C., the OHP fixed lid sequence causes the drive motor to rotate at the above-mentioned conveying speed to drive the conveying belt 44 and the fixing device 45. The transfer material P falling above
The transfer material P is conveyed to the fixing device 45 and re-fixed.

In addition, in the OHP mode, the conveyor belt 44 and the fixing device 4
The image reading system A, laser writing system B, image forming section C, paper feeding section, etc. other than 5 are not driven.

That is, at the time of re-fixing, since image formation is not performed, the means necessary for image formation are inactive, and only the conveyance belt 44 and the fixing device 45 necessary for re-fixing are operated.

The toner used in the color copying machine of this embodiment is made by dispersing dyes and pigments in polyester resin and pulverizing it to a weight average particle size of 3 to 12 μm. C. was used.

Further, as the fixing device 45, the heat roller is made of an aluminum core coated with fluorine resin and has a diameter of about 30 mm, the pressure roller is made of an iron core coated with silicone rubber and has a diameter of about 30 mm, and a heating lamp is used. The total pressure by the 600 W halogen lamp and the roller pair of the fixing device 45 is 17 kg at 30 mm. However, it goes without saying that the present invention is not limited to these.

The rotating member 53 of the re-fixing cassette 50 may be rotated by the operator himself, but by inserting the re-fixing cassette 50 into the apparatus main body, the rotating member 53 engages with a gear provided on the apparatus main body. The rotating member 53 may be automatically rotated to cause the transfer material to fall onto the conveyor belt.

Further, the re-fixing cassette 50 which stores only one transfer material to be re-fixed as in this embodiment may be used, but it may also be a re-fixing cassette 60 which can store a plurality of transfer materials as shown in FIG. The re-fixing cassette 60 has a movable part 62 slidably provided on a frame body 61, and protrudes from the frame body 61. A member 63 is provided. Further, the frame body 61 includes a fixing portion 64.
is permanently installed. On the other hand, a guide member 57.5 provided in the main body of the apparatus for attaching and detaching the re-fixing cassette 60
Recesses 65 and 66 corresponding to 8 are provided in the re-fixing cassette 60.

This re-fixing cassette 60 is inserted into the main body of the apparatus in the same way as the re-fixing cassette 50, the sliding member 63 is slid, and the movable part 62 is slid. Then, the transfer materials supported by the movable part 62 and the fixed part 64 are supplied to the conveyor belt one by one.

Furthermore, in this embodiment, pressing the OHP button 47 on the operation panel 46 switches the OHP mode to J2. A means may be provided and the detection signal may be used to automatically set the ○HP mode. Note that as this detection means, existing detection means such as a 7-oto coupler or a microswitch can be used.

FIG. 6 shows a transfer drum type image recording apparatus as another embodiment to which the present invention is applied.

The transfer drum type image forming apparatus has a transfer drum 70 in contact with the transfer portion of the image carrier 30, and the transfer drum 50 rotates counterclockwise in synchronization with the image carrier 30. A transfer material is wrapped around the outer periphery of the transfer drum 70, and the image carrier 3 is placed on the wrapped transfer material.
After the toner images of each color formed on the transfer material are transferred, and the toner images of each color are superimposed on the transfer material, they are separated from the transfer drum 70 and discharged to the upper part of the apparatus main body after being rated.

A charger 71 is provided at the peripheral edge of the transfer drum 70 to electrostatically attract the transfer material. Transfer material to transfer drum 70
A winding member 72 is provided for mechanically winding the transfer material, and the winding member 72 has a roller at its tip and comes into contact only when the transfer material is first wound around the transfer drum 70. Furthermore, a gripper 73 is provided on the circumferential surface of the transfer drum 70, and acts to hold the leading end of the transfer material that is synchronously conveyed. The transfer device 40 electrostatically transfers the toner image on the image carrier 30 onto a transfer material. The separation claw 74 separates the transfer material after transfer from the transfer drum 70.

The transfer material fed from the paper feed cassette 75 is synchronized by the timing roller 42 and enters the transfer drum 70 charged by the charger 71, so that the leading edge of the transfer material reaches the gripper 7.
3, the winding is wrapped around the member 72, and rotated to the transfer section, where the yellow (Y) toner image formed on the image carrier 30 by the transfer device 40 is transferred onto the transfer material. . Transfer drum 70 that has finished the first transfer
continues to rotate and transfer the next toner image. That is,
The second rotation is a magenta (M) toner image, the third rotation is a neutral (C) toner image, and the fourth rotation is a black (B) toner image.
K) The toner images are transferred one after another in a superimposed manner.

When the transfer of the four-color toner image is completed, the transfer material is separated by releasing the holding of the leading edge of the transfer material with a separating claw and transferred to the fixing device 3.
5, and the toner image on the transfer material is fixed. Thereafter, the transfer material is discharged outside the image forming apparatus. The above is the image formation in the normal mode.

Next, using the above-described transfer drum type image forming apparatus, I;
This section explains re-fixation in cases where:

First, an image is formed on the transfer material in the above-mentioned normal mode, and the transfer material, which has been fixed once and is ejected from the apparatus, is placed in the re-fixing cassette 50 (see FIG. 2 or FIG. 5).
60).

Then, the re-fixing cassette 50 is set in the apparatus main body with the recesses 55 and 56 aligned with guide members 57 and 58 provided on the apparatus main body. Further, when the rotating part 53 of the re-fixing cassette 50 is rotated, the movable part 52 rotates, and the leading edge of the transfer material P placed on the notch 52A is moved onto the conveyor belt 4.
4. Drop it on top.

Then, the OHP button 47 on the operation panel 46 is pressed (see FIG. 3). By this pressing operation, as shown in FIG. 4, the OHP mode is input to the control means, drive motor speed control and fixing temperature control are output, and the conveying speed of the conveying belt 44 and the fixing speed of the fixing device 45 are set to the normal mode. In addition, the fixing temperature of the fixing device 45 is increased by 10 to 4 compared to the normal mode.
The temperature is controlled to increase by 0°C.

Then, when the fixing temperature of the fixing device 45 rises to a predetermined temperature, the OHP fixing sequence causes the drive motor to rotate at the above-mentioned conveyance speed, drive the conveyor belt 44 and the fixing device 45, and drop the film onto the conveyor belt 44. The leading edge of the transfer material P is pulled, and the transfer material P is conveyed to the fixing device 45 for re-fixing.

〔Effect of the invention〕

As described in detail above, the present invention involves forming an image on a transfer material such as an HP film in a normal mode, storing the once-fixed transfer material in a re-fixing cassette, and transferring the transfer material to a fixing device again. This is a color image forming apparatus that transports images.

As a result, the color image forming apparatus of the present invention performs re-fixing even when the color image is not sufficiently fixed, and furthermore, when re-fixing, the conveyance speed of the transfer material is slowed and the fixing temperature is increased, thereby reducing the image quality. Black (B)
K) component image area yellow (Y) toner, magenta (M
) toner and /an (C) toner are overlapped and are sufficiently melted and mixed with each other, making it possible not only to form a color image with good saturation and good color balance, but also to have excellent gloss and light transmittance. ; Color images can be obtained. In addition, in the re-fixing mode, the image forming section is not driven, and the once-fixed transfer material is directly supplied to the fixing device, so the transfer material to be re-fixed does not touch the image carrier, i.e. , re-fixing can be performed without damaging the image carrier. Furthermore, by using a re-fixing cassette even in a small device, it is possible to provide an image forming device that can re-fix images with a simple mechanism without providing a special transport path. .

[Brief explanation of the drawing]

FIG. 1 is a main sectional view of a color copying machine to which the present invention is applied. Figure 2 shows a re-fixing cassette that can accommodate one sheet of transfer material. FIG. 3 is a diagram showing the operation panel. FIG. 4 is a diagram showing control means in re-fixing mode. Figure 5 shows a re-fixing cassette that can accommodate multiple sheets. FIG. 6 is a main sectional view of a transfer drum type image forming apparatus to which the present invention is applied. 30... Image carrier 35... Charger 36Y
, 36M, 36C, 368K...Developer 40...
Transfer device 39...Cleaning device 44...
・Transport belt 45...Fixing device 46...Operation panel 47...○HP button 50, 60...Re-fixing cassette 70...Transfer drum

Claims (4)

[Claims] (1) A transfer means for transferring the toner image on the photoconductor onto a transfer material, a conveyance means for conveying the transfer material onto which the toner image has been transferred by the transfer means, and the transfer conveyed by the conveyance means. A fixing means for fixing the toner image on the material; and a removable device capable of storing the transfer material once fixed by the fixing means and feeding paper to the fixing means for fixing the transfer material again. A color image forming apparatus comprising: a transfer material storage means capable of storing a transfer material; (2) The color image forming apparatus according to claim 1, wherein the transfer material storage means is removably provided above the conveyance path of the transfer material by the conveyance means. 3. The color image forming apparatus according to claim 1, further comprising a control means for setting fixing conditions different from previous fixing conditions when fixing the transfer material that has been fixed once again. (4) The color image forming apparatus according to claim 1, wherein the storage means is capable of storing a plurality of transfer materials.