JPS6249369A - Multicolor recording device - Google Patents

Abstract

PURPOSE:To attain high resolution by providing a heating means for applying heat for temporarily fixing each toner image to the surface of a latent image carrier. CONSTITUTION:A laser beam is irradiated from the 1st semiconductor laser element 3a to the surface of a photosensitive drum 1, a latent image corresponding to the 1st color is formed, and when the 1st latent image reaches the 1st developing unit 4a part, the 1st latent image is developed by the 1st color toner. When the 1st toner image reaches near the part corresponding to an oven fuzer 20, the toner layer starts to melt and is temporarily fixed on the surface of the photosensitive drum 1. When a laser beam radiated from the 2nd semiconductor laser element 3b is irradiated to the surface of the drum 1, a latent image corresponding to the 2nd color is formed and developed by the 2nd color toner in the 2nd developing unit 4b. Since the 1st toner image temporarily fixed on the surface of the drum 1 is developed by the 2nd developing unit 4b, the hue of the toner image is not lost by the 2nd developing unit 4b.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a multicolor recording device such as an electrophotographic recording device or an electrostatic recording device that is capable of recording recorded images in multiple colors. This invention relates to an improvement in a multicolor recording bag d that allows a multicolor recorded image to be obtained by simply rotating an image carrier once.

[Prior Art] As a conventional multicolor recording device of this type, for example, Japanese Patent Application Laid-Open No. 1986-
There is one published in Publication No. 163961. This device records, for example, a three-color image, and as shown in FIG. 7, has a photosensitive drum 1 as a latent image carrier that rotates in a predetermined direction. is provided with a pre-charger 2 that charges the surface of the photosensitive drum 1 to a predetermined potential in advance, and around the photosensitive drum 1 are three semiconductor laser elements 3 (specifically, 3a, 3b, 3
C), and developing units 4 (specifically, 4a, 4b, 4c) corresponding to different color components (for example, cyan, yellow, magenta) are arranged at the rear of each semiconductor laser element 3.
) are respectively disposed, and furthermore, a transfer device 6 is disposed behind the final stage developing device 4C to transfer each toner image formed on the photosensitive drum 1 onto a transfer paper 5 as a transfer medium. It is what it is. In FIG. 7, reference numeral 7 denotes a cleaner for removing residual charge and residual toner on the surface of the photosensitive drum 1 after the transfer process.

In such a multicolor recording device, a first semiconductor is applied to a photosensitive drum 1 which has been charged to a predetermined potential, and a -11 probe 3 is applied.
A latent image corresponding to the first color is formed in step a, and the first latent image is developed with toner in the first developing device 4a. A latent image corresponding to the color is formed, and the second developing device 4b develops the second latent image with toner, and then the final stage semiconductor laser element 3c on the photosensitive drum 1 is used to develop the third color. A latent image is formed, and the third latent image is developed with toner in the final stage developing device 4C. Next, each toner image is transferred to the transfer paper 5 via the transfer device 6, and a fixing step (not shown) is performed. The transferred image is fixed on the transfer paper 5 through the following steps. Therefore, in such a multicolor recording apparatus, a plurality of images, three colors in this example, are simultaneously transferred onto the transfer paper 5 during one rotation of the photosensitive drum 1.

[Problems to be Solved by the Invention] However, in such a conventional multicolor recording device, there are various problems! Although the single layer of toner developed by the toner developing unit 4 is held on the photosensitive drum 1 with a certain degree of adhesion, the holding force is not sufficient, and the latent image is transferred to the toner by the subsequent developing unit 4b or 4c. During development, there is a risk that part of the toner layer developed by the preceding developing device 4a or 4b may peel off. For this reason, the toner image is disturbed, or the peeled toner gets mixed into the subsequent developing device 4b or 4c, and the toner of each color is mixed with each other in the subsequent developing device. A situation may arise in which the color tone of the toner image is impaired and the quality of the transferred image is degraded accordingly.

In order to deal with this situation, conventionally, as shown in FIGS. 8 and 9, in order to clearly divide the latent image developing area for each color, the photosensitive drums of each developing device 4 are 1
A slit plate 9 having a large number of slits 9a provided at predetermined intervals is provided in each opening portion 8 facing the slit plate 9, and the positions of the slits 9a of each slit plate 9 are set so as not to overlap with each other. There is. According to this type, only the area corresponding to the position of each slit 9a of each slit plate 9 is regulated as a latent image development area, so that a part of the first layer of toner developed earlier gets mixed into the later developing device. This situation can be effectively avoided. However, in this type,
Since the pitch p between the slits 9a limits the resolution of the toner image and, ultimately, the transferred image, a problem arises in that obtaining a high-resolution transferred image requires passing.

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned problems, and effectively prevents toner from being mixed into the developing means and disturbs the toner image on the latent image carrier. To provide a multicolor recording device that can obtain high-resolution transferred images at high speed while suppressing the amount of image transfer.

That is, the present invention provides a rotating latent image carrier, a plurality of latent image forming means for forming latent images on the latent image carrier, and toners of different colors provided corresponding to the respective latent image forming means. Assuming that the multicolor recording apparatus is equipped with a plurality of developing means for developing each latent image, and a transfer means for transferring the multicolor toner image developed by each developing means onto a transfer medium, The body is provided with heating means for applying heat to the extent that each of the toner images is temporarily attached to the surface of the latent image carrier.

In such technical means, the design of the latent image carrier may be appropriately changed as long as it can carry the latent image formed by the latent image forming means, and the latent image carrier may be a photosensitive drum, a photosensitive belt, etc. A body or a conductive substrate whose surface is coated with a dielectric material is used. Furthermore, various types of latent image forming means may be used, such as one that forms a latent image using light such as a laser, or one that forms a latent image using an ion stream. Historically, various developing methods can be used as the developing means, and the number, arrangement, toner color, etc. of the developing means may be appropriately selected. Furthermore, as for the transfer means, various types such as a thermal transfer method or an electrostatic transfer method may be adopted, but since one layer of toner on the latent image carrier is temporarily attached by the heating means, this toner layer Since a relatively large amount of energy is required to peel off and transfer the image, a thermal transfer method is preferable.

Further, the above-mentioned heating means has at least a latent and image bearing member portion corresponding to the subsequent developing means excluding the initial developing means as a heating area, and furthermore, the heating means may be heated as appropriate depending on the physical properties of the developing means and the toner. It is necessary that the temperature is given. In this case, the heating means may be provided at one or more locations outside the latent image carrier, or may be provided inside the latent image carrier. The heating temperature of the heating means is assumed to be between the glass transition point and the melting point of the toner, and to the extent that the first layer of toner developed does not peel off when passing through the subsequent developing means. Setting 1 to provide strong wearing power
It is necessary to

[Function] According to the above-mentioned technical means, the heating means heats the surface of the latent image carrier corresponding to the developing means to an appropriate temperature, so that the latent image formed by the latent image forming means When the latent image is developed with toner by the developing means, each layer of toner constituting the toner image is not only held by electrostatic force, but also temporarily adhered to the latent image carrier beyond the glass transition point. . Therefore, even if the toner image on the latent image carrier passes through the subsequent phenomenon means part, a part of each toner layer constituting the toner image does not easily peel off, and the toner image on the latent image carrier Situations in which the image is disturbed or toners of other colors are mixed into the developing means are effectively avoided. In addition, since the toner particles from the developing means are transferred to the latent image side without groove shoulders, the toner density of the toner image formed is extremely dense, which makes it possible to improve the toner image, and ultimately the transferred image, with high resolution. It becomes possible to make it into something.

[Embodiments] Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

◎Example 1 The multicolor recording device shown in Fig. 1 records two-color images, and its basic configuration includes a photosensitive drum 1 whose surface is coated with a photosensitive film such as amorphous silicon. , a plurality of semiconductor laser elements 3 (specifically, 3a, 3b) used as a latent image forming means and emitting a laser beam of, for example, a wavelength of 780 nl, and a plurality of semiconductor laser elements 3 (specifically, 3a, 3b) arranged in a direction tangential to each semiconductor laser element 3 and having a different color. A developing device 4 (specifically, 4a, 4b) that transfers toner, a transfer roll 16 that transfers each toner image onto transfer paper 5, and an oven fuser that is a heating means that heats the surface of the photosensitive drum 1. It is equipped with 20. In FIG. 1, reference numeral 2 denotes a pre-charger such as a scorotron, and 7 denotes a cleaner for removing residual toner and residual charge on the photosensitive drum 1.

In this embodiment, the developing device 4 adopts a two-component magnetic brush developing system, and this magnetic brush (not shown) is arranged so as to be movable forward and backward with respect to the photosensitive drum 1, and when not developing, the developing device 4 adopts a two-component magnetic brush developing system. While being spaced apart from the surface of the drum 1,
J'3 is arranged in contact with the surface of the photosensitive drum 1 during development.

Further, in this embodiment, the toner used has a glass transition point of 70° C. and a melting point of 160° C., and an epoxy resin is used as the toner binder.

Further, the oven fuser 20 includes a first developing device 4a.
and the second semiconductor laser element 3b, and when the circumferential speed of the photosensitive drum 1 is 160 m/Sec, the temperature near the surface of the photosensitive drum 1 corresponding to the second developing device 4b is reduced to 10 m/sec.
It is designed to be set at 0 to 120'C.

Therefore, according to the multicolor recording apparatus according to this embodiment, assuming that the surface of the photosensitive drum 1 is charged in advance to a predetermined potential by the pre-charger 2, first, the first semiconductor laser element 3
agaranoshi ~ the beam is irradiated onto the surface of the photosensitive drum 1,
A latent image corresponding to the first color is formed on the surface of the photosensitive drum 1. Thereafter, when this first latent image reaches the first developing device 4a, the magnetic brush of the developing device 4a comes into contact with the surface of the photosensitive drum 1, and the first latent image is formed by the first color toner. Toner is developed. When the first toner image reaches the vicinity of the area corresponding to the oven fuser 20, a layer of toner constituting the toner image exceeds the glass transition point and begins to melt, and is temporarily attached to the surface of the photosensitive drum 1. . Next, when the surface of the photosensitive drum 1 is irradiated with the laser beam from the second semiconductor laser element 3b, the photosensitive drum 1
A latent image corresponding to the second color is formed on the surface, and this latent image is toner-developed with the second color toner in a second development tgIi%i4b. At this time, the first toner image passes through the second developer (GL device 4b), but since this first toner image is temporarily attached to the surface of the photosensitive drum 1, this toner image There is no possibility that a part of the toner layer is peeled off and mixed into the second developing device 4b.This prevents the 1-toner image on the photosensitive drum 1 from being disturbed in the developing process. Second developing device 4b
The color tone of the toner image will not be impaired by. Furthermore, in each developing process, the toner from each developing device 4 transfers seamlessly to the latent image, so that the toner density of each toner image is set to a dense state. When the toner images of the respective colors reach the transfer roll 16, each toner image is thermally transferred onto the transfer paper 5 by the transfer roll 16, and this transferred image 17 is reliably transferred onto the transfer paper 5 through a fixing step (not shown). The image is fixed, and one image recording process is completed.

Since such an image recording process is performed during one rotation of the photosensitive drum 1, the recording speed can be increased compared to a type in which the photosensitive drum 1 is rotated multiple times, and not only can the image recording process described above Regarding the recorded images,
It has been experimentally confirmed that the desired color tone can be maintained, and the toner image can have a fine toner density, resulting in a high resolution, which supports the operation of the multicolor recording device according to this example. It turns out.

◎Example 2 In FIG. 2, unlike in Example 1, the multicolor recording apparatus according to this example includes a heater 30 as a heating means inside the photosensitive drum 1, and a non-magnetic component as the developer 4. It uses a non-contact development method. To be more specific, the developing device 4, as shown in FIG.
Consisting of a metal roll 42 and a pressing blade 41 made of an elastic body, an AC bias is applied between the metal roll 42 and the photosensitive drum 1 to appropriately move the toner particles back and forth between the latent image and the metal roll 42. It is designed to move
Polystyrene is mainly used as the toner binder for the toner used in this embodiment.

The heater 30 is arranged so that the circumferential speed of the photosensitive drum 1 is IG.
At O#/sec, the temperature of the surface of the photosensitive drum 1 corresponding to the second developing device 4b is designed to be set at 80 to 90°C.

In this example, it has been confirmed that the same effects as in Example 1 are achieved. In this case, since the heating temperature of the heater 30 is set lower than in Example 1, the degree of temporary toner adhesion is smaller than in Example 1; Since the peeling force acting on the toner is smaller than that in Example 1J, no 1-toner contamination occurs in the developing device 4.

Furthermore, in this embodiment, since the entire surface of the photosensitive drum 1 is heated by the heater 30, even if the surrounding environment is highly humid, the moisture on the surface of the photosensitive drum 1 is effectively removed by the heat of the heater 30. Therefore, the situation in which the quality of the recorded image is impaired by moisture can be more effectively avoided than in the first embodiment.

◎Example 3 In Fig. 4, the multicolor recording device according to this example is different from each of the above-mentioned examples, and is designed to record three-color images, and has three types of recording devices for forming latent images corresponding to each color. Semiconductor laser elements 3 (specifically, 3a, 3b, 3c) are disposed, and three developing devices 4 (specifically, 4a, 4b, 4c) are disposed for developing each latent image with toner of a different color. Furthermore, an oven fan 20 (specifically 20a, 2
0b). It has been confirmed that with this multicolor recording apparatus, a three-color recorded image can be obtained with the desired color tone and high resolution, as in each of the above embodiments.

◎Example 4 In Fig. 5, the multicolor recording device according to this example records two-color images, and unlike Example 1 above, the periphery of the conductive substrate (for example, an aluminum drum) is made of polyethylene. A dielectric drum 11 coated with a dielectric material such as terephthalate is used as a latent image carrier, and a tII type contact head 13 (on the ion flow side) is used as a latent image forming means.
Specifically, 13a and 13b) are used. As shown in FIG. 6, the write head 13 includes a discharge wire 52 to which a bias from a DC power supply 51 is applied, and a shield 53 that surrounds the discharge wire 52 and is partially grounded. Dielectric drum 1 of the shield 53
1, a large number of control electrodes 54 are provided with an insulating layer 55 interposed therebetween, and each control electrode 54 and the corresponding shield 53 wall, and the insulating layer 55 are provided with ion ejection channels 56.
By opening the control electrode 54 and applying appropriate positive and negative pulse signals to the control electrode 54, the ion flow generated around the discharge wire 52 is controlled at the ion ejection path 56 portion.

Therefore, according to the multicolor recording apparatus according to this embodiment, in addition to achieving substantially the same effects as those of the above-mentioned embodiments, it is possible to form an ion latent image overlapping F of the toner image that has already been formed. Therefore, it is possible to provide a wider range of color reproducibility than in each of the embodiments.

[Effects of the Invention] As explained above, according to the multicolor recording device according to the present invention, the toner image on the latent image carrier is temporarily attached by the heat of the heating means, so that the above-mentioned problem can be achieved. This makes it possible to prevent a part of the toner image from peeling off when the toner image developed by the developing means passes through the developing means at the subsequent stage. It is possible to prevent the toner from being mixed in, and the color tone of the recorded image can be kept good accordingly.In addition, the toner from the developing means can be distributed to the latent image without any gaps, so the toner in the toner image can be The density can be made finer, thereby increasing the resolution of the recorded image. Furthermore, according to the multicolor recording device of the present invention, it is only necessary to rotate the latent image carrier once to obtain a multicolor recorded image, so there is no risk of impairing the high recording speed. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing Embodiment 1 of the multicolor recording device according to the present invention, FIG. 2 is an explanatory diagram showing Embodiment 2 of the multicolor recording device according to the invention, and FIG. FIG. 4 is an explanatory diagram showing the details of the developing device, FIG. 4 is an explanatory diagram showing Embodiment 3 of the multicolor recording apparatus according to the present invention, FIG. 5 is an explanatory diagram showing Embodiment 4 according to the present invention, and FIG. FIG. 7 is an explanatory diagram showing an example of a conventional multicolor recording device; FIG. 8 is an explanatory diagram showing an example of the structure around a developing device in the conventional system; FIG. The figure is an explanatory diagram showing details of the slit plate in FIG. 8. [Description of No. n] (1)...Photosensitive drum (latent image carrier) (3)...Semiconductor laser element (latent image forming means) (4)...Developer (
Developing means) (11)...Dielectric drum (latent image carrier) (13)
...Writing head (latent image forming means) (16) ...Transfer roll (transfer means) (20) ...Oven fuser (
Heating means) (30)...Heater (heating means) Patent applicant Fuji Xerox Co., Ltd. Agent
Patent attorney Tomohiro Nakamura (2 others)

Claims (1)

[Claims] A rotating latent image carrier, a plurality of latent image forming means for forming latent images on the latent image carrier, and developing each latent image with toner of a different color and provided corresponding to each latent image forming means. In the multicolor recording device, the multicolor recording device is equipped with a plurality of developing means, and a transfer means for transferring the multicolor toner images developed by the respective developing means onto a transfer medium. A multicolor recording apparatus characterized in that each of the toner images described above is temporarily attached to the surface of a latent image carrier by heat from a heating means.