JPH02310574A - Copying and printing device - Google Patents

Abstract

PURPOSE:To simultaneously perform copying and printing at high resolution by forming an electrostatic latent images at exposure intensity which is changed in response to original copying, original print and print for a copied matter and impressing a developing bias voltage which is changed in response to the exposure intensity. CONSTITUTION:On a photosensitive body 1, either copying exposure by an analogue optical system or printing exposure by a digital optical system using a liquid crystal shutter array 8 is performed. After the exposure, another exposure is performed on the photosensitive body 1. Then each maximum exposure intensity of both optical systems on the photosensitive body 1 is set lower than the maximum exposure intensity capable of being exposed on the photosensitive body 1 and the sum of both types of exposure intensity is set as the maximum exposure intensity capable of being exposed on the photosensitive body 1. Besides, in response to the copying exposure intensity, the printing exposure intensity and synthesized exposure intensity, the bias voltage of a developing device 9 is changed and developing is performed. Thus copying and printing is simultaneously performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus having both copying and printing functions.

[Conventional technology and its issues]

Copying machines currently in use include a photoconductor, a charger that charges the surface of the photoconductor to a certain polarity, and a charged photoconductor drum. an optical section that directly projects an electrostatic latent image, a developer that applies developer to the electrostatic latent image on the photosensitive drum, and a developer that applies the developer on the photosensitive drum to the paper conveyed from the paper feed mechanism. This is a dry electrophotographic copying machine equipped with a transfer device that transfers the agent and a fixing device that fixes the transferred image onto paper.

In addition, in recent years, many printer devices have been commercialized that use a digital exposure system in which image information is given as an electrical signal to the exposure system of this dry type electrophotographic copying machine, and this is converted into an optical signal to expose the photoreceptor to create an image. has been done.

Recently, systems that integrate a copying apparatus and a printer have been commercialized because the above-mentioned copying apparatus and printer have a common image creation process other than the exposure system.

Copy printer devices currently on the market expose and scan the original image, break it down into pixel units, photoelectrically convert it into density information, combine this with print information, convert it back to optical information, and print it onto the photosensitive surface. This is a device that forms an image. However, image processing and printing of photoelectrically converted digital information requires complex processing and is expensive, and the accuracy of the reading system affects the image, resulting in lower resolution than copying devices using analog optical systems. Poor gradation.

On the other hand, a method has been proposed in which an optical image formed by an analog optical system and an optical image formed by a digital optical system are simultaneously formed on a photoreceptor using a mirror (Japanese Unexamined Patent Publication No. 57-1
00453).

However, when operating two functions simultaneously, for example when printing on the white part of a copy of an original, the first
As shown in Figure 5, the image area 42 of the copying section has an initial charging potential of approximately 40, and in the white area of the copying section, that is, the non-image area 46, the charged photoreceptor's potential decreases to approximately the ground potential 41 due to exposure, and this area Since image information is printed, it is not possible to create a latent image having the same potential level as a copy. In other words, it is not possible to copy and print at the same time.An object of the present invention is to solve the above-mentioned problems and provide an apparatus that can copy and print at the same time.

[Means to solve the problem]

In order to achieve the above object, the present invention has devised the exposure and development of the photoreceptor in a system having an electrophotographic copying function and a printing function. This is how it was done.

That is, in a copy printer device equipped with an analog optical system that exposes an original onto a photoreceptor, a digital optical system that exposes print data onto the photoreceptor, and a developer that develops the photoreceptor, the analog optical system exposes the photoreceptor to a copy. Or, in addition to configuring an apparatus that can expose one print using a digital optical system and then expose the other, the photoreceptor can be exposed to the maximum exposure intensity of both optical systems on the photoreceptor. The sum of the two is the maximum exposure intensity that can be used to expose the photoreceptor, and the bias voltage of the developing device is changed depending on the exposure intensity for copying, printing, and the combination of both. It is characterized by being configured to do the following.

Another feature of the above-mentioned system is that it is an apparatus in which part of the analog optical system and the digital optical system are shared.

Another feature of the digital optical system is that it uses a liquid crystal shutter array as a means for converting print data into an optical signal that can be used to expose a photoreceptor.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic sectional view illustrating a copy printer device using the present invention for dry electrophotography, and FIGS. 2a and 2b are diagrams each illustrating the potential of an electrostatic latent image formed by this device.

In FIG. 1, 1 is a photosensitive drum, 2 is a charger that charges the surface of the photosensitive drum to a certain polarity, 6 is a lamp, 4 is a mirror, 5 is a transparent document transfer table, 6 is a document, and 7 is a photoconductor. A SELFOC lens that forms an optical image on the surface; 8 is a liquid crystal shutter array; 9 is a developer sleeve; 10 is a toner;
11 is paper, 12 is a transfer device, and 13 is a fixing device.

First, when copying an original, the light from a lamp is focused by a mirror 4 and is applied to an original 6 placed on an original moving table 5. The light reflected by the original is imaged on the photosensitive drum by the self-occurring lens 7, and an electrostatic a image proportional to the density of the original is formed on the photosensitive drum 1, which is uniformly charged by the charger 2. In this embodiment, as shown in FIG. 2a, the charged potential of the photoreceptor is not sufficiently lowered to near the ground potential 22 even at a time when the white portion of the document, that is, the maximum reflected light energy is present, and more specifically, approximately 1/2 of the initial charged potential 20. shall be. At this time, since the image area 26 is hardly exposed to light, the potential is close to the initial charging potential 20. Therefore, an electrostatic latent image is formed between a potential of 1/2 of this initial charging potential and the initial charging potential 2o. When developing in such a state, prevent the toner 10 from adhering to the non-image area 5.
In order to prevent background fog from occurring, as shown in FIG. Apply. The formed electrostatic latent image is made visible by applying toner 10, and then the toner 10 on the drum is transferred to the paper 11 conveyed from the paper feeding mechanism by a transfer device 1.
Transfer in step 2. Finally, this transferred toner image is fixed by a fixing device 13 to form a copy.

Next, when using a printer, the light from the lamp O is opened and closed by a liquid crystal shutter array 8 separated by cells with a certain pitch.
Optical information matching the image information is sent, and an image is formed on the drum surface by the cell 7 oxygen lens 7 to form an electrostatic latent image matching the image information. At this time, an electrostatic latent image is formed between 1/2 of the initial charge and an initial charge potential of 200, as in the case of original copying, and the developing bias potential 21 is also set higher than the charge potential of the non-image area 24. When printing on a copy of the original, for example, when printing on a white area, the photoreceptor is re-exposed by opening and closing the liquid crystal shutter 8 on the electrostatic latent image produced by the copy.
As shown in Figure 2, the potential of the non-image area 26 is lowered to a state close to the ground potential 22 where the photoreceptor is almost uncharged, and the print area 27 is not exposed to light but has an initial electrostatic latent image potential due to copying. The charging potential is approximately 1/2 of the charging potential 20.

At this time, the potential of the original copy latent image 29 becomes the potential of the latent image 28, which is approximately the same potential as that of the printing section 27.

Further, during development, in order to prevent the toner 10 from adhering to the non-image area 26, a developing bias voltage 25 having a potential slightly higher than the potential of the non-image area 26 is applied.

In this way, by changing the exposure intensity to form an electrostatic latent image potential for original copying, printing, and printing on copies, and applying different developing bias voltages 25 accordingly,
This can be achieved with a single mechanism that combines the three functions described above.

Figure 3 shows another embodiment of the present invention, in which a liquid crystal shutter array is used as a means for converting electrical signals into optical signals in a digital optical system, and a part of each of the analog and digital optical systems is shared. In the embodiment, a half mirror 14 is used so that the lamp 6, mirror 4, and selfoc lens 7 are shared. This allows the device to be made smaller and lower in price.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain an apparatus that can perform both copying and printing functions with high resolution using a simple optical system, and can also perform copying and printing at the same time.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view illustrating the configuration of a copy printer according to the present invention, FIGS. 2a) and (b) are explanatory diagrams showing the charging potential of the photoreceptor of the copy printer according to the present invention, and FIG. 4 is a schematic sectional view for explaining another embodiment of the present invention, and FIG. 4 is an explanatory diagram showing the charging potential of a photoreceptor in a conventional copy printer device. 1...Photosensitive drum, 2...Charger, 6...Lamp, 4...
Mirror, 5... Original moving table, 6...
Original, 7...Selfoc lens, 8...LCD shutter array, 9...
Developer sleeve, 10... Toner, 11 Old paper, 1
2...Transfer device, 13...10. Fixing device, 14...Half mirror-0 Fig. 1 2nd cause (Q) 24, Non-direct Yi Kodu (Dew XJ evil) 22.7 bend? Niden I F Fig. 2 (b) 20, ``1711A band t1 (standing 22, t12 electric

Claims (3)

[Claims] (1) Convert print data into optical signals using an analog optical system that forms an optical image of the document to be copied onto a photoreceptor and exposes it to light, and a means that converts an electrical signal into an optical signal, and converts the optical signal onto the photoreceptor. In a copy printer device comprising a digital optical system that images and exposes it to light, and a developer that attaches a developer to an electrostatic latent image formed on a photoreceptor by exposure, the analog optical system or digital It is possible to perform exposure using one of the optical systems and then perform exposure using the other, and the maximum exposure intensity on the photoreceptor by each optical system is lower than the maximum exposure intensity that can expose the photoreceptor, and the sum of both is This is the maximum exposure intensity that can be used to expose the photoreceptor, and the bias voltage of the developing device is changed according to the exposure intensity that the photoreceptor is exposed to, and the operation is one of copying and printing, or a combination of both. A copy printer device characterized by being capable of. (2) The copy printer apparatus according to claim 1, wherein a part of the analog optical system and the digital optical system are shared. (3) The copy printer apparatus according to claim 1 or 2, characterized in that a liquid crystal shutter array is used as means for converting electrical signals into optical signals.