JPS597381A - Image forming device - Google Patents

Abstract

PURPOSE:To enable the arbitrary setting of the magnetification between the 1st and the 2nd latent images by changing the relative speeds of forming bodies for the 1st and the 2nd latent images. CONSTITUTION:An insulation drum 1 is so arranged as to be driven at the revolving speed varied according to the magnification for copying by a motor 16 and a control circuit 19 for the motor. An electrostatic charger 3 or 8 is controlled according to the revolving speed of the the drum 1 in the stage of forming the secondary latent image on said drum. More specifically, control circuits 20, 21 for high voltage and the circuit 19 are directly connected to the lever 25' of a setter 25 for variable magnification provided in a display part 17. If the relative speeds of the forming bodies for the 1st and the 2nd latent images are changed in the above-mentioned way, the magnification between the 1st and the 2nd latent images are set as desired.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus that visualizes a latent image formed in correspondence with an original image, and particularly to an image forming apparatus that visualizes a latent image formed in correspondence with an original image. The copying magnification between the latent image and the latent image can be set as desired using a simple structure.

In the conventional image forming device t6 of this type, in order to achieve the variable magnification function of changing the magnification of the latent image with respect to the incident light image, the positions of the lenses and mirrors constituting the optical system are made to be different from those at the same magnification C1. The moving speed of the document illumination lamp was changed. Therefore, the number of lenses and mirrors is 1.
? The movement (b) is performed by driving a motor via a clutch, and the clutch also needs to be used for changing the moving speed of the document illumination lamp and mirror (2). Moreover, immediately after the start of such movement, it is moved due to the ifit nature! Since the degree of Ii/i is not constant, variable scale poems have
In order to change the run-up distance, where the movement speed is not constant, according to the magnification, it was necessary to keep the home position at the start of movement constant.

Furthermore, as the interlocking speed of the latent image forming body, such as the rotational speed of the photosensitive drum, is changed, it becomes necessary to change the operating conditions of auxiliary means, such as the voltage applied to the charger and the static eliminator.
Because a photoreceptor is used in the photoreceptor drum, there are related conditions for the charger and static eliminator. It was not possible to simply change the value in proportion to the value, but it was necessary to control it using a complicated configuration.

In addition, when reducing a latent image on a latent image forming body such as a photoreceptor with respect to an incident light image, for example, a light image of B4Z size is reduced to AI/, a latent image of size L, 2 is reduced to B When developing images on transfer paper of size B4Z to A
&Size part is subtracted from ars s +′, which will be described later.
The remaining portions, such as portions E and F of yJ(B), are completely blackened during development because the photoreceptor is not exposed. Therefore, when reducing, original 4 (゛Jth!)
A blank exposure lamp is installed separately from the opening lamp.
It is necessary to expose the remaining portion, and if the reduction ratio is different, it is necessary to accurately change the timing of irradiation by the blank exposure lamp.

Therefore, the conventional image forming apparatus of this type has a serious drawback in that it is necessary to perform extremely complicated control when changing the magnification.

An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional art and to provide an image formation r! which allows the image forming magnification to be set to any desired value by the control of simple configuration 1 without the need for complicated control.
iJ% position.

The present invention will be described in detail below with reference to the drawings.

First, an example of the overall configuration of the FIFi made by image forming according to the present invention is shown in FIG. 1, an example of the d) detailed configuration of the swamp image forming part is shown in FIG. 2, and an example of the drawing of the control circuit is shown in FIG. 3. The arrangement of the display section is shown in FIG.

In the configuration shown in the first diagram, / is an insulating drum which has an insulating surface layer and performs transfer of an electrostatic latent image, visualization by development, and transfer of a single image, which will be described later, and - is a photosensitive surface layer. The photosensitive drum 3 that forms an electrostatic latent image using an incident light image is an insulating drum/
'f't' which makes the insulating surface layer uniformly 1 [shift 1]
j m device, g is tGiJ, the wholesale lamp that exposes the margin residual j■;; A charger 7 uniformly covers the photosensitive surface layer of the photosensitive drum; A charger is used to transfer the electrostatic latent image onto the insulating surface layer of the insulating drum /. A charger for transferring the toner image on the insulating surface layer of / onto the transfer paper, // a belt for conveying the transfer paper, and 7.2 an insulating drum for transferring the developed image on the insulating surface layer of /. A cleaner removes the subsequent toner, /3 is a roller that guides the transfer paper, and /g is a roller that feeds the transfer paper.

81) Regarding the control system shown in Figure 3, 73 TJ photosensitive drum 2
A motor that drives the insulated drum, a motor that drives the insulated drum, and a motor that drives the insulated drum.
The displayed display ffdl, 1g, /9 is motor /3. /
The motor control circuit that controls each of B, θ, 2/ is '
If'I is a high-voltage control circuit that applies high voltage to each electric appliance 3J, and the display section /7 shows a hotel meter 2 that adjusts the motor control circuit /9 with a tap 22, and a high-voltage control circuit θ, 2/ is a potentiometer knife which is adjusted by tap n' and 2g', respectively, and 2g is the step.

The process of copying with the above-mentioned configuration will be explained with reference to the latent image forming section shown in the second figure.
, 2d is sprayed with CdS, and an insulator is sprayed on top of it, forming a three-layer structure. A band of 10 g is applied between the surface of the photosensitive drum 2 and the conductive substrate. A high voltage of 5 KV is applied and corona discharge is performed to uniformly charge the surface of the photosensitive drum with a positive charge. In order to maintain the surface potential of the photosensitive drum 2, add it once: t'l 'Ffl
In addition, the injection efficiency of negative charge is increased by irradiation with the lamp 7, and positive charging is performed again. Then, the incident light image is applied to the surface of the photosensitive drum 2 at the same time as negative corona discharge by the charger j. Light M = J.

Incidentally, the incident light image is projected onto the surface of the photosensitive drum 2 by irradiating the document /j with the illumination lamp /g and sequentially passing through the mirror 7''/shi 9/7b, the lens /, and the mirror /70.

At this time, in bright areas, that is, white areas of the original, Cd
The resistance value of the S layer decreases, and the captured negative charges become more mobile.Furthermore, as the positive charges on the surface of the photosensitive drum disappear due to the application of negative corona discharge, the negative charges of the CdS layer are released from their restraints. and is emitted to the conductive substrate.

On the other hand, in dark areas, that is, image areas of the original, Cd5
Since the resistance value of N is high, the negative charge in the CdS layer remains unchanged. However, although the positive charge on the insulated wire is removed to some extent by the application of negative corona discharge, the removed charge is secondly raised on the conductive substrate to maintain electrical balance. At this stage, the surface potential of the photosensitive drum 2 is zero in both bright and dark areas.
No potential contrast is formed. That is, II
Although charges exist in the H portion, no potential appears.

Next, when the surface of the luminescent drum 2 is uniformly irradiated with a fuse lamp l, in the bright area, the Cd
No change occurs because the charges on both the S layer are removed '11-5, but in the 11)5 part, the negative charge, which is not bound by the positive charge on the CclS layer, moves easily. This results in binding to the positive charges in the conductive substrate and neutralizing them. However, is there still a residual positive charge on the insulating layer? I? , the load appears on the outside as a 1113 optical drum surface layer, and immediately becomes a static T17 image.

Next, a bias voltage of -3° OKV is applied to the photosensitive drum J itself, and a negative corona discharge is applied from the inside of the photosensitive drum λ by ``:ik Tj'6'' to form a negative corona discharge on the surface of the photosensitive drum. The primary latent image is transferred onto the surface of an insulating drum separated by about 2 mm.
Insulated drum/
The top is negatively charged to form a secondary latent image. The insulating drum / is uniformly positively charged by the charger 3, and in the dark area where a positive charge is generated on the surface of the photosensitive drum, the electric field shown by the thin line in Figure 2 is in the direction in which negative ions are accelerated. The negative ions from the latent image transfer charger are attracted by this applied electric field, pass through the holes in the mesh, and reach the surface layer/a of the insulating drum. As a result, in a certain part of the image, the surface layer /a of the insulating drum / becomes negatively charged.

On the other hand, in bright areas where there is no positive charge on the surface of the insulating drum, the electric field is weaker than in dark areas, and the amount of negative ions absorbed by the conductive substrate of the mesh is greater than the amount of negative ions circulating through the holes in the mesh. . Therefore, the influence of corona discharge hardly appears on the surface of the insulating drum.

The electrostatic latent image formed on the insulating drum as described above is developed into a toner image by the developing device 9, and is transferred onto paper fed in the direction B in the figure by the charger θ. The transfer paper conveyed by roller /3 is separated from the insulating drum / by separation roller /g, and is moved to C shown in the figure by conveyor belt //.
The powder image is fixed by a fixing device (not shown).

Next, when changing the copy magnification, a case of reduction will be described as an example.

In the control system shown in FIG. 3, the photosensitive drum 2 is
And the motor control circuit /g rotates at the same speed both in the case of full size copying and in the case of variable size copying. Note that the motor /j also drives an optical system (not shown) that guides the incident light image in conjunction with the photosensitive drum 2. Also, a photosensitive drum! - The process of forming the first latent image on H is as described above. On the other hand, the insulating drum / is driven by a motor /6 and a motor control circuit /W while changing its rotational speed according to the copying magnification. Therefore, the motor 6 is constituted by a type of motor such as a DC motor whose rotational speed can be changed continuously.

Then, when forming the second m-image on the insulated drum/, the rotational speed of the insulated drum l\/ is, for example, when the copying reduction rate is set to 1, the insulated drum/
Times such that the circumferential speed of is the same as when copying at the same size! In this case, it is necessary to control the charger 3 or g according to the rotation speed of the insulating drum. Therefore, high voltage control circuit〃, 2/ and motor control circuit /9
are adjusted respectively using the potentiometer n, nog and 〃 provided on the display section/7.

These potentiometers n to nog are interlocked with each other and are directly connected to the lever Δ' of the variable magnification setting device r provided on the display section 7 shown in FIG.

11th. In the illustrated display section 7, 2O is a copy number setting key, a sword is a copy button, and 2g is a copy number display, all of which are the same as those in a general copying machine. In the illustrated example, the variable magnification setting device Δ is capable of setting the copying magnification from L to G, and can be set to any magnification in between using the lever blade'. Each tap n' to 2'l' directly connected to this lever Δ' moves, and each control circuit 22
~2g is adjusted according to the set magnification. Note that the insulating drum/ is not equipped with a photoreceptor, therefore, each charger 3.
1 need only be controlled in accordance with the rotational speed of the insulating drum 1, and there is no need to establish a relationship between them.

Furthermore, as mentioned above, when a reduced latent image is formed on the photosensitive drum 2 as described above, it is necessary to perform blank exposure to prevent blackening of the margin in the image frame of the same size as the original image. In the above example, if the electric field applied to the charging device for latent image transfer is applied only when corresponding to the latent image portion on the photosensitive drum λ, the non-image portion of the image forming drum is uniformly charged. Therefore, no matter how large the transfer paper is compared to the size of the copied image, the margins will not turn black.

In addition, in the case of enlarged copying, the rotational speed of the insulating drum is increased compared to the case of full-size copying.

As is clear from the above description, according to the present invention, a latent image of an input image formed on a photosensitive drum is transferred.

In an image forming apparatus such as a copying machine that visualizes images, the copying magnification of an output image can be set to any desired value with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a side view schematically showing an example of the overall configuration of the image forming apparatus of the present invention, FIG. 2 is a side view schematically showing an example of the detailed configuration of the latent image forming section, and FIG. 3 is a control circuit thereof. FIG. 1 is a block diagram showing an example of the configuration, and FIG. 9 is a top view showing an example of the configuration of the display section. /...Insulating drum, /a...Surface insulating layer,
/b...conductive substrate, c...photosensitive drum, 2
aN, 2d...Metshu, 3,! ;, la,, 6b, I, /θ... Charger, ri,
7...Exposure lamp, 9...Developer, l/...
Conveyor belt, /2...Cleaner, /3. /ri...roller, /S, /Otsu...motor, /7...
Display section, 7g, /q...Motor control circuit, 〃, 2/...High voltage control circuit, 22-211...
Potentiometer, n'~2'...tap,
Δ...Magnification ratio setting device, B'...Lever, 26...Copy number setting key, Katana...Copy button, I...Copy number display, ψ...Variable voltage source , G/...voltage source.

Claims (1)

[Claims] A second latent image formed by transferring the /th latent image formed on the photoconductive layer provided on the /th latent image forming member to an insulating layer provided on the second latent image forming member is visualized. The image forming apparatus is characterized in that the magnification between the first and second latent images can be arbitrarily set by changing the relative speed of the first and second latent image forming bodies. Image forming device.