JPS5995551A - Image forming device - Google Patents

Abstract

PURPOSE:To enable image formation in any cases of exposing to light from a lens system or to laser beams without any change from a sole apparatus by combining the first exposure device having the lens system with the second exposure device using laser beams and arranging them around a photosensitive body of two-layer structure consisting of the first and the second photoconductive layers different in photosensitive spectral wavelength. CONSTITUTION:Negative electrostatic charging is carried out with a primary electrostatic charger 18 and a positive latent image corresponding to an original is formed by imagewise exposure with the first exposure device 5 and development is executed to make a copy from an ordinary original. In the case of copying using an image signal supplied from the second exposure device 6, that is, the writing device of a laser or the like, long wavelength light is irradiated while negative electrostatic charging is executed with a primary electrostatic charger 18 and then positively charged with a secondary electrostatic charger 19 to render the surface potential of a photosensitive body 3 to near zero. Then, negative potential is produced only on the irradiated parts with laser beams to write image information and it is developed. As a result, a copy can be made by using the same apparatus and somewhat changing an electrostatic charging system alone for each purpose, without performing reversal development or the like.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention provides an analog image using a lens system, a laser, an L
The present invention aims to provide an image forming apparatus that can copy digital images produced by ED or the like using the same apparatus.

[Technical background of the invention and its problems]

Analog image by lens system and LED
Copying digital images such as those made using the same device is an indispensable technology for creating multi-functional image forming devices, such as copying machines with printer functions and ink-printing machines with editing functions. It is. However, there is a problem in combining the Carlson process used in conventional copying machines with the Grosses, which has a writing type optical system such as a laser or LED. The former creates a positive latent image, whereas the latter converts the image signal into light and irradiates it, so the light becomes a latent image and requires a separate development process. In order to solve this problem, it is possible to create a positive latent image by irradiating the area where there is no image signal with light, but this method causes fogging unless the potential of the area that should be white is completely erased. There is a major problem in that it is not possible to obtain high-quality images.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its purpose is to provide a relatively simple method for copying analog images using a lens system and copying digital images using lasers, LEDs, etc. using the same developing device. Although the composition is
The purpose is to provide an image forming apparatus that has both functions the same as a single device 6 and also has a function of freely overlapping two copies.

[Summary of the invention]

In order to achieve such an object, the present invention provides a first photoconductive layer on an image carrier having first and second photoconductive layers having different spectral wavelengths.
After applying a charge of polarity, image exposure is performed, and then the first
a first image forming means for developing with a developer having a second polarity opposite to the polarity of the charge; and a first photoconductive layer of the image carrier that transmits light that makes only the first photoconductive layer conductive to the image carrier. A charge of a first polarity is applied to the image carrier while irradiating the image carrier with a primary charge, and a charge of a second polarity opposite to the first polarity is then applied to the image carrier. By performing secondary charging, the absolute value of the surface potential of the image carrier is reduced, and then, the first photoconductive layer, which has been made conductive during the secondary charging, is irradiated with light of a wavelength to which it is exposed. By performing convolution with the signal, a potential of the first polarity is generated only in the image signal portion,
A second image forming means for subsequent development is provided.

EXAMPLES The present invention will now be described with reference to examples shown in the drawings. FIG. 1 shows an electronic copying machine used to carry out the present invention. In the figure, 1 is a main body, on which a document table 2 is provided.

Further, a drum-shaped photoreceptor 3 as an image carrier that rotates in a predetermined direction in synchronization with exposure scanning of the original on the original platen 2 is provided approximately in the center of the main body 1. Around the body 3 are a charging device 4, an imaging section 5a of a first exposure device 5, a beam light irradiation section 6a of a second exposure device (writing device) 6, a developing device 7, a transfer device 8, and a stripping device. 9. The cleaning devices 10 are sequentially arranged along the rotation direction of the photoreceptor 3.

Inside the main body 1, there is a paper feed path 13 that guides the transfer material P selectively supplied from the cassette of the paper feed device f4.11.12 between the photoreceptor 3 and the transfer device 8, and a peeling path 13. Device 9
A paper discharge path 16 that guides the transfer material P onto which the peeled developer has been transferred to the tray 15 via a pair of paper discharge rollers 14 and 14.
is formed.

A fixing device 17 for fixing the developer image on the transfer material P is provided in the middle of the paper discharge path 16.

The charging device 4 includes a primary charger 18 and a secondary charger 19 provided on the downstream side of the primary charger 18, that is, on the side in the rotational direction of the photoreceptor 3. - Wide charger 1
Reference numeral 8 has a structure including a tungsten lamp 18a and a long wavelength transmission filter 18b, and a secondary charger 19 has a structure having a scorotron structure.

The first exposure device 5 is composed of a lens optical system having an exposure lamp 2O whose back is surrounded by a reflector, a mirror 21, a mirror 22, a lens 23, and a mirror 24. The mirror 21 moves at a speed equal to the circumferential speed of the photoreceptor 3, and the mirror 22 moves at the same speed as the mirror 21, thereby scanning an original (not shown) on the original platen 2 and placing it on the photoreceptor 3. Slit exposure is performed to double the size.

Further, the second exposure device 6 includes a laser optical system,
Exposure is performed by irradiating a laser beam in accordance with an image signal.

In addition, in the figure, 25 is a cooling fan, and 26 is a main motor.

Further, as shown in FIG. 2, the photoreceptor 3 as an image carrier is made of selenium/tellurium light having a thickness of 40 μm, which is sensitive to long wavelengths, on a conductive substrate 27 such as AA, as shown in FIG. A conductive layer 28 and a zinc oxide photoreceptor layer 29 having a thickness of 25 μm and sensitized with rose bengal, which is not sensitive to long wavelengths, were successively layered as shown in FIG. 4. Next, a latent image forming process is performed by a first exposure device 5 consisting of a lens optical system, and a second exposure device 6 consisting of a laser optical system.
The latent image formation process using digital signals was explained by uA.
do.

First, a latent image forming process using the first exposure device 5 consisting of a lens optical system will be explained. FIGS. 5 and 6 show the movement of charge and the change in surface potential, respectively. In the figure, (A-1) is a charging portion. In this embodiment, negative charging is performed at 0.2 μq/cm with respect to 0 potential. Correspondingly, a positive charge is induced in the conductive substrate 27, resulting in 450
A negative potential of v is generated. (A-2) is the exposed part,
The dark part remains at negative potential, and the light part remains at the light guide II layer 2.
Both layers of 8 become conductive and the surface potential becomes close to zero. Therefore, by developing a positive latent image with a positively charged toner, a positive image can be obtained.

Next, the process of forming a latent image using a digital signal such as a laser signal will be explained. FIGS. 7 and 8 show the movement of charge and the change in surface potential, respectively. In the figure (B-
1) is the −th charged part and passes it through a sharp cut glass filter (using Toshiba R67) so”T: 10,
000 Lux of light from the tungsten lamp 18a, negative charging is performed at about 0.5 μq/cyn with respect to 0 potential.

In addition, since the lower photoconductive layer 28 is conductive, a negative charge is multiplied on the surface of the photoreceptor 3, and a positive charge is induced on the upper part of the lower photoconductive layer 28, resulting in a 1ooov higher negative charge. A potential is generated. Next, as shown in (B-2), positive secondary charging is performed at approximately 0.2 μq- with respect to the o potential to erase a part of the negative charge on the surface of the photoreceptor layer 29, and as a result, the surface potential becomes zero. Make it close. Next, as shown in (B-3), G
An aAsAt semiconductor laser with a wavelength of 785 nm is used to irradiate an image signal such as a character as a light spot. As a result, only the lower photoconductive layer 28 is electrically charged, and positive charges that compensate for the negative charges remaining on the surface remain on the lower photoconductive layer 28. As a result, only the irradiated area has a sufficient voltage of 400V. becomes a high negative potential. Therefore, by performing regular development using the same positively charged toner as in the lens system process, it is possible to convert image signals such as characters into toner images. Furthermore, in the conventional process, a photoreceptor layer 29 with no long wavelength sensitivity was laminated on a photoconductive layer 28 with long wavelength sensitivity.
A similar process can be achieved even if the number of laminated layers is changed. FIG. 9 shows the charge distribution of the process. In Figure 7 (
(C-1) corresponds to B-1). In this case, since the upper photoreceptor layer 29 is made conductive by the long wavelength light, negative charges are transferred onto the lower photoconductive layer 28. Corresponding positive charges are induced in the conductive substrate 27. Next (C-2)
By positively charging the surface of the photoreceptor layer 29, the surface potential of the photoreceptor layer 29 is made close to zero, as shown in FIG. Next, as shown in (C-3), by irradiating the laser, only the irradiated part of the upper photoreceptor layer 29 becomes conductive, and as a result, a part of the negative charge on the upper part of the lower photoconductive layer 28 is erased. , positive charges corresponding to the remaining negative charges are induced to the conductive substrate 27, and as a result, a sufficient negative potential is generated in the irradiated area. Therefore, although the structure of the photoreceptor is different and the charge distribution is different as shown in FIGS. 7 and 9, the potential changes are exactly the same as shown in FIG. 8.

Next, an embodiment of an image forming apparatus capable of executing these processes will be described with reference to FIG. 1 again.

First, the photoreceptor 3 is charged according to a predetermined procedure using a primary charger 18 having a tungsten lamp 18a and a long wavelength transmission filter 18b, and a secondary charger 19 having a scorotron structure. A document (not shown) on the document table 2 is illuminated by the exposure lamp 20, and the lens 2
A latent image is formed by forming an image on the photoreceptor 3 through a photoreceptor 3 or by irradiating the image signal with a second exposure device 6 consisting of a laser optical system. Next, the developer device 7 develops the toner image, the transfer device 8 transfers the toner image onto the transfer material P conveyed from the cassette of the paper feed device 11 and 12, the peeling device 9 peels it off, and the fixing device 17 The image is fixed and the paper is ejected to the tray 15.

The remaining toner on the photoreceptor 3 is cleaned by a cleaning device. Although not shown here, it is of course possible to provide a static eliminator for improving cleaning efficiency, a lamp for erasing the memory, etc., without any problem.

Next, the image forming method using the first exposure device 5 consisting of a lens optical system and the second exposure device (writing device) 6 consisting of a laser optical system is the same as shown in FIGS. 5 to 8. , and the necessary operations of each unit up to the formation of the final latent image are shown in FIGS. 10 and 11. When the operation panel (not shown) selects a process using a lens system, ie, copying from a normal original or copying a CRT screen, the operation shown in FIG. 10 is performed. In other words, the primary charger 18 in FIG.
Only the charger operates to perform negative charging, image exposure is performed by the first exposure device 5 consisting of a lens optical system, and a positive latent image corresponding to the original is created and the process proceeds to development. Next, when copying the image signal from the second exposure device 6, that is, a writing device such as a laser, is selected, as shown in FIG. Next, the surface potential of the photoconductor 3 is made close to zero by positively charging it with a secondary charger 19, and then a negative potential is generated only in the irradiated area by writing image information with a laser or the like, and then development is performed. . As described above, the same device can be used to make positive copies of originals using the second exposure device (writing device) 6, using the developing device 63 under exactly the same conditions, with only slightly different charging methods and no reversal development, such as characters, etc. An image obtained by irradiating the image signal as a light spot can also be copied.

The primary charging in the long-wavelength light described above is intended to make the photoconductive layer 28, which has long-wavelength sensitivity, conductive. The same thing will happen if the battery is initially charged while the battery is being charged. Furthermore, the polarities of the charging and developing methods described so far were only selected because they are suitable for the photoconductive layer 28 of this embodiment. Of course it will get better.

Furthermore, although the description has been made so far as to execute only one of the processes, it is also easy to execute these processes at the same time. In other words, after executing one process, the same process or another process is executed overlappingly without transferring or cleaning, and by repeating as necessary, a superimposed toner image is created and transferred in one go. is good.

It is easy to perform a small transfer without performing transfer or cleaning, and the transfer only requires stopping the conveyance of the transfer material P and the output of the transfer corona, and the cleaning device 7 only needs to be separated. Also, it is natural that the developing device used at this time should be one that does not disturb the previous image during superimposition; for example, a non-contact imager as shown in FIG. 12 is suitable. 3 in the figure is the photoreceptor, and a layer of toner is placed on the developing roller 30 with a rubber blade 3, and the power source 32 is AC 400 Hz, 600 V, DC-10.
A bias synthesized from 0V is added.

Furthermore, so far, we have only described the process of using the lens optical system in the case of making a positive copy from a positive original, but the process of making a positive original from a negative original can easily be added.

This can be done by simply performing a charging process using a copy of an image signal from a writing device such as a laser, and then performing image exposure. Furthermore, the photoconductive layer 28 in the embodiments so far has been a combination of one with long wavelength sensitivity and one without.
It is not limited to this. What is necessary is to combine a photoreceptor layer with sensitivity in a certain wavelength range and a photoreceptor layer without sensitivity. In the distribution, both photoquaternary layers can be made conductive, and in the distribution of an image to be copied such as black, at least one of the photovoltaic layers must not be made quadrielectric.

〔Effect of the invention〕

As explained above, according to the present invention, copying of an analog image using a lens system and copying of a digital image using a laser, LED, etc. can be performed with a relatively simple configuration using the same developing device. It is possible to provide an image forming apparatus which is not much different from a stand-alone apparatus, and which also has the function of superimposing two copies on top of each other.

[Brief explanation of drawings]

1 to 11 show an embodiment of the present invention, in which FIG. 1 is a schematic longitudinal sectional front view, FIG. 2 is an explanatory diagram showing the layer structure of the photoreceptor, and FIG. 3 is an illustration of the photoreceptor. FIG. 4 is an explanatory diagram showing the spectral sensitivity of the photoconductive layer; FIG. 5 is an explanatory diagram showing the state of charge distribution when an electrostatic latent image is formed by the lens optical system; FIG. 6 is an explanatory diagram showing the state of surface potential change when an electrostatic latent image is formed by the lens optical system, FIG. 7 is an explanatory diagram showing the state of charge distribution when an electrostatic latent image is formed by the laser optical system, and FIG. Figure 8 is an explanatory diagram showing the state of surface potential change when forming an electrostatic latent image using a laser optical system, and Figure 9 shows the state of charge distribution when forming an electrostatic latent image using a photoreceptor with a different layer structure. Explanatory diagram,
Fig. 10 is a timing chart showing the operating state of each device up to latent image formation by the lens optical system, Fig. 11 is a timing chart showing the operating state of each device up to latent image formation by the laser optical system, and Fig. 12 is a timing chart showing the operating state of each device up to latent image formation by the laser optical system. 1 is a diagram showing a non-contact type developing device that can be applied to the present invention. 3... Image carrier (photoreceptor), 4... Charging device, 5...
...First exposure device, 6...Second exposure device, 7...
-Developing device, 8...Transfer device, 18...-wide charger, 19...Secondary charger. Applicant's representative Patent attorney Takehiko Suzue 3 Figure 2 3 Figure 3 j Skin length (nm) Figure 4 400 500 600
7005 Skin length (nm) Figure 5

Claims (1)

[Scope of Claims] (After applying a charge of a first polarity to an image carrier having first and second photoconductive layers having different spectral wavelengths, imagewise exposure is performed, and then the first polarity is A first image forming means for developing with a developer having a second polarity opposite to the polar charge, and a first photoconductive layer of the image carrier that applies light that makes only the first photoconductive layer conductive to the image carrier. While irradiating the image bearing member, a charge of a first polarity is applied to the image carrier to perform primary charging, and then a charge of a second polarity opposite to the first polarity is applied to the image carrier. By performing secondary charging, the absolute value of the surface potential of the image bearing member is reduced, and then the first photoconductive layer, which has been made conductive during the secondary charging, is irradiated with light of a wavelength to which it is exposed. An image forming apparatus characterized in that it is equipped with a second image forming means that performs writing by a signal and develops after generating a potential of the first polarity. (2) Second image forming Among the means, the conductivity is increased by irradiating only the first photoconductive layer with light that makes the first photoconductive layer conductive at the timing of applying the second polarity charge in order to reduce the absolute value of the surface potential of the image bearing member. The image forming apparatus according to claim 1, characterized in that the image forming apparatus is configured to perform the image forming process while the image forming apparatus continues to operate. , the second photoconductive layer has no sensitivity in the predetermined band.
The image forming apparatus described in . (4) The image forming apparatus according to item 1, wherein the image formed on the image carrier by the first image forming means and the second image forming means is transferred at one time. (5) The image forming apparatus according to claim 1, wherein the development is performed by magnetic or non-magnetic non-contact development. (6) It is characterized by having an image forming process of creating a positive image from a cinema original by performing image exposure of the first image forming means instead of performing writing using an optical signal by the second image forming means. An image forming apparatus according to claim 1.