JPH01100565A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent an exposing means from flickering and having voltage variation by connecting a resistance to a power supply and turning a fixing means when the exposing means is in operation. CONSTITUTION:A controller 30 functions as the power supply which supplies electric power to a fixing lamp 21 and an exposure light source and a semiconductor switch 39 which is connected to the exposure light source 4 through a resistance 35, an exposure switch (including resistances R1-R3) 36 is connected to a fixing lamp driving circuit SSR 34. When an original platen moves by specific size, an original platen position detection switch 33 is turned on sand then while the exposure light source 4 illuminates at the same time, the controller 30 inhibits the fixing lamp 21 from being supplied with the electricity. Consequently, variation in source voltage due to the fixing lamp 21 is precluded and the supply voltage to the exposure light source 4 is stabilized.

Description

[Detailed description of the invention] U) Industrial application field The present invention relates to an image forming apparatus such as an electronic copying machine.

(B) Conventional technology Exposure means for irradiating a photoreceptor with a reflected light image of a document include a Helog 7 lamp system using AC phase control and a fluorescent lamp system using an inverter or the like.

In the former method, from the waveform of the commercial power supply, the phase angle required as the exposure voltage is determined from among all phases by a semiconductor switch (such as a special amplifier), and the output voltage is determined. Since feedback is provided and correction is made at the same time when the commercial power supply fluctuates, the amount of light reflected from the original onto the photoreceptor is always constant, and the amount of light can be changed steplessly.

Further, in the latter fluorescent lighting method, since a secondary power source is used, noise is low and the heat generation of the light source is also low.

(c) Problems to be solved by the invention However, in the above-mentioned halogen lamp method, since the power supply waveform is continuously turned ON and OFF, it is very easy to generate noise, which requires expensive countermeasures. do not have. Furthermore, t-lap and the like when the light is turned on at a small phase angle also poses a problem.

In addition, with the above-mentioned fluorescent lamp method, the lamp itself becomes larger, its life deteriorates, and preheating is required.
There are many problems such as the need for a feedback circuit for the amount of light to be obtained, and it is inevitable that the device will become larger and more expensive.

The present invention has been made in view of the above problems, and has low noise and
It is an object of the present invention to provide an image forming apparatus equipped with a small-sized and low-cost exposure means.

1) Non-invention of means to solve problems. An image forming apparatus comprising: an exposure means for irradiating a reflected light image of a document onto a photoreceptor; and a fixing means for fixing a recording paper onto which a toner image has been transferred;
The image forming apparatus is characterized in that the exposure means is connected to a power supply via a resistor, and is further provided with a control device that makes the fixing means inoperative while the exposure means is in operation.

(E) Function The exposure means is connected to the power supply via a resistor, and is provided with a control device that disables the fixing means while the exposure means is in operation, so that the current flowing to the resistor exposure means is provided. The rush current is suppressed, and the non-operation of the fixing means eliminates the influence of the rush current flowing through the fixing means on the exposure means.

(f) Example A case in which the invention is applied to an electronic copying machine will be described below.

In Figures M1 and 83, (1) is a photoconductor drum rotatably mounted in an apparatus main body (not shown), and a photoconductive material such as amorphous silicon is coated on the circumferential surface of a metal cylindrical body. The cylindrical body is grounded.

Above the photoreceptor drum (1) is a transparent glass platen (2) that scans back and forth from side to side with an original placed thereon.
A short focus lens array (for projecting and forming a document image onto the photoreceptor drum (1) is installed between the document table (2) and the top of the photoreceptor drum (1). 3) is provided.

An exposure light source (exposure means) (4) for exposing the entire surface of the document is provided to the right of the short focus lens row (3). This exposure light source (4) is provided with a through hole (6J) at the lower part of the reflecting mirror (5) in order to also expose the downstream side of the I\iJ short focus lens array (3).

A charging corotron (7) for uniformly charging the photoreceptor drum tIJ is provided below the exposure light source (4). In this charging corotron (7), a discharge wire (9) is stretched inside a shield case (3), and a mesh metal grid (IG) is stretched over the opening surface of this shield case (8). The ground is grounded via a varistor 1111t.

On the downstream side (left side) of the short focus lens row (3), a static elimination lamp tta is provided for eliminating unnecessary i-electric potential on the photoreceptor drum (13). On the downstream side, a developing device σ is used to develop an electrostatic latent image formed on the photosensitive drum (1) by a charging corotron (7), a short focus lens array (3), etc. using toner. Seven are deployed.

A transfer corotron r1G is provided at the bottom of the photosensitive drum (υ) for transferring the toner image σ3t-U onto the recording paper σω on the photosensitive drum (1).

(17) is a cleaning blade that removes untransferred toner remaining on the photoreceptor drum (1) without being completely transferred to the eQ paper a9.

The key is a document table position detection switch t for detecting the position of the document table.

This is the fixing device (fixing means), the delay lamp +217
It is composed of a heating roller with a built-in 7α field and a pressure roller (4) that is pressed against the heating roller σ mark.

FIG. 2 is a block diagram showing an example of the previous control system. This electronic copying machine is controlled by a control device (G) including a CPU.
Copy start SW3υ, heating roller temperature detection circuit c1
3. The document table position detection switch [present] is connected.

In addition, when the control device is installed, it has a function as a power source that supplies power to the light source (4).
Between the control device is a fixing lamp drive circuit (SSR) for driving the slender JJ, an exposure switch (including resistors (R1) (Fi2) (Ha)), and an exposure light source (4 ) is connected to the semiconductor switch (zero cross). 87) (to) is fuse.

Next, the operation of the wood butt case will be explained according to FIGS. 83 and 4.

When the power supply switch f (not shown) is turned on, the heating roller temperature detection circuit port is activated, and the fixing lamp 2 lamp 0 is turned on by the control device via the fixing lamp drive circuit aa'.

Thereafter, the light is turned on and turned off repeatedly within a certain temperature range.

When Copy Star) SW (II) is operated, the original platen y
The turn clap (not shown) operates and the document table (2)
moves to the right and the static elimination rung 4 lights up. When the document table (2) moves by a predetermined distance, the document table position detection switch is turned ON, and at the same time, the exposure light source (4) is turned on and the control liquid is turned on to the fixing lamp V. This prevents fluctuations in the power supply voltage due to the fixing lamp 1211 and stabilizes the supply voltage to the exposure light source (4). A part of the light beam emitted from this exposure light source (4) is transmitted through the through hole (6) of the reflecting mirror (5) (Fig. 1!1) t-
As the document platen (2) moves further to the right, the charging corotron (force and The transfer corotron σG operates, and at the same time a developing bias is applied to the developing device σ4, and the upstream sides of points B and D of the photoreceptor drum (11) are charged by the respective corotrons (7). )).

At this time, an electrostatic latent image has not yet been formed on the portion of the photoreceptor drum (1,) facing the developing device σ, so even if a developing bias is applied, the toner (13) is not attached to the photoreceptor drum. (Adding a layer to υ is a word.

The document platen (2) temporarily stops at the rightmost position, the document platen feed clutch (not shown) operates, and the document platen (2) starts to move to the left, and the photoconductor drum ( 1) A silent latent image corresponding to the original image is formed on the upstream side of point C (third
cause G/9).

When the latent image passes through the shadow formed on the upstream side of point C of the photoreceptor drum (1) in front of the developing device α bump, the darkness 'I! The LfM image is developed with toner (13), but the downstream side of the C point is neutralized by the static elimination lamp α3, so toner does not adhere to this Q region (N3 and 9).

Thereafter, at the same time that the point C of the photosensitive drum (1), that is, the downstream negative end of the toner image plane, reaches the position facing the transfer corotron 4, the recording paper α4 is supplied, and the toner image αJ is )). When the document table (2) moves and scans to the left and the entire surface of the document table (2) is exposed, the document table field clutch becomes inactive, and at the same time, the document table jitter/clutch is activated. Move the manuscript table (2) to the right again! Start I (in Figure 3)). Note that the area where the electrostatic latent image is formed is up to point E on the photoreceptor drum (1).

Immediately after the upstream end of the electrostatic latent image, that is, the point E of the photoreceptor drum (1), passes completely in front of the static eliminating lamp U, the static eliminating lamp (
1 and 4 are lit, and the Ejtl1 of the photoreceptor drum (1)
The upstream side of the point is exposed, and the static electricity is removed (Figure 3 (E)).
).

While the document table (2) is moving to the right again, the document table position detection switch is turned ON, and the exposure light source (4) is turned OFF.
Then, the fixing lamp Q11 is enabled to be energized. After this, the power supply to the fixing lamp 121I is controlled by the heating roller temperature detection circuit (3). Therefore, the exposure light source (4)
goes out (see Figure 3), the upstream side of point C of the photosensitive drum (υ) is not neutralized by the exposure lamp (4), but is charged by the transfer corotron 11. , are superimposedly charged by the synthetic corotron (7) (
Figure 3 (G).

Then, after all the toner image α3 on the photosensitive drum (1) is transferred to the recording paper 15i and after NFC, the charging roller/(
7) When the transfer roller rlG stops, the developing bias to the developing device α is also released (Fig. N3 (G)).
).

After the copying operation fP- is completed, in order to neutralize the remaining portion on the photoconductor drum (1), the static neutralization force is applied until the point F of the photoconductor drum (1) passes the static neutralization force α'Jft again. After the lamp continues to be lit and the entire area of the photoreceptor drum (1) is neutralized, the static elimination lamp α2 is turned off and the drive motor is also stopped.

By the way, the resistor (c) in the N2 diagram is for suppressing the current when the exposure lamp is turned on, and can suppress the rush current, which normally flows several tens of amperes, to less than half, and can significantly reduce noise. .

The fixing lamp (due to the rush current of 2 IJ) can be avoided by forcibly turning off the fixing lamp while the exposure light source is on.

FIG. 5 is a waveform diagram of the exposure light source and power supply of the Kihide example, and as is clear from the figure, no noise is generated.

In addition, the resistor (R1) (R1) is connected to the exposure switch (to).
(R3) can be selected. Therefore, three-stage switching is possible by setting the resistances (Fil) (R1) (R1)i to slightly different values. Furthermore, by increasing the number of poles of the exposure switch (to), it is possible to increase the number of lenses to 40. Therefore, it is possible to correct the difference in power supply voltage depending on each region (by using a two-volt switch).

(g) Effects of the Invention As is clear from the above description, the exposure means is connected to the power supply through a resistor, and is provided with a control device that disables the fixing means while the power supply is in operation. This makes it possible to prevent flickering and voltage fluctuations in the exposure means, as well as to prevent noise.In addition, there is no need for an enlarged exposure light source, no deterioration of its life, no need for preheating, and there is no need for a feedback circuit. Therefore, it is possible to aim at downsizing and lowering the cost of the device.

[Brief explanation of the drawing]

1 to 5 each show an embodiment of the present invention,
Figure 1 is a block diagram showing the outline of the electronic copying machine, N2@J is a block diagram of the control system, Figure 3 is a time chart showing the operating costs of each part), Figure 84 shows the main parts at each point in Figure 3. Corresponding action state l! ! FIG. 5 is a diagram showing the power supply waveform of the exposure light source. (1)...photoreceptor, (4)...exposure light source (1m light means), rice cake...heating roller, [Co., Ltd.]...pressure roller,
(2-ton fixing lamp, ■... foot layer device (fixing means),
Sir...control device, can...resistance, (g)...exposure switch t0

Claims (1)

[Scope of Claims] 1. An image forming apparatus comprising: an exposure means for irradiating a photoreceptor with a reflected light image of a document; and a fixing means for fixing a recording paper onto which a toner image has been transferred. . An image forming apparatus, characterized in that the exposure means is connected to a power supply through a resistor, and further includes a control device that deactivates the fixing means while the exposure means is in operation. 2. An image forming apparatus characterized in that an exposure switch is provided between the exposure means and the power supply for adjusting the amount of light from the exposure light source.