JPS63125962A - Copying machine - Google Patents

Abstract

PURPOSE:To blue a border, make a trimming copy, copy a part of an image with normal density and others thin by providing a light emission quantity specification control means which supplies a light emission quantity specifying signal to a light emission quantity variation driving means according to the movement timing of a photosensitive body and the position of a light emitting device. CONSTITUTION:A control part 11 carries on the illumination of an LED by a system through a resistance as to the right and left sections delta1 and delta5 of a blank lamp 5 and performs switching to driving by a driving system using a variable power source as to center sections delta2, delta3 and delta4. Then, a drive current is varied up to 0 in a specific border period as to the section delta3. Further, an intermediate drive current value between a drive current value passed through the resistance R and the drive current value in the section delta3 is employed. All LEDs are turned on at the end as shown by alpha. Thus, trimming copying operation wherein only the image of the center part of an original is taken in performed and a copy image I0 whose border is blurred is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a copying machine, and more particularly to a copying machine in which the shading of an image can be partially adjusted.

2. Description of the Related Art In a conventional copying machine, as shown in FIG. 6, it is known that a blank lamp 51 is placed opposite a photosensitive drum 50 and that the blank lamp 51 is used to trim an image.

That is, the individual LEDs 51°, 51 of the blank lamp 51
h, . . . are turned on or off by a drive circuit 52 as shown in FIG. 7, the electrostatic latent image formed on the photosensitive drum 50 is exposed to light, and the electrostatic latent image in the exposed portion is exposed. Trimming is performed by erasing.

For example, as shown in FIG. 8, at the beginning of the period when the electrostatic latent image formed on the photosensitive drum 5° passes directly under the blank lamp 51, all the LEDs 51□, 51b, .
A current 10 is applied to .
Turn on the LED in the +03 section, and switch to the center section D2.
The LEDs of LE051=, 51h, .

Then, as shown in FIG. 9, the portion of the electrostatic latent image (2) initially formed on the photosensitive drum 5° that initially passes directly under the plank clamp 51 is the LED 51. ．． 511
．． , , etc., and for the partial molecule 2 passing in the middle period, the left and right sections, D, are erased, and the electrostatic latent image ■' remains in the central section D2, The electrostatic latent image is completely erased in the part of the molecule that passes through at the final stage. Note that X is the rotational direction of the photosensitive drum 50, that is, the traveling direction of the electrostatic latent image I.

As a result, only a copy of the image in the center of the document is obtained, which means that the image has been trimmed.

“As an inverse application of this trimming, masking can also be performed.

As such a conventional copying machine, for example, Japanese Patent Application Laid-Open No. 61-20
The device described in Japanese Patent No. 065 can be mentioned.

Problems with the Prior Art The conventional copying machine described above was able to leave some of the electrostatic latent image and erase the other, but since it was only possible to choose between leaving and erasing, both The boundaries were very clear.

For this reason, even if it is desired to naturally blur the boundaries, there is a problem that this cannot be done.

In addition, there are cases where it is desired to make a faint copy of other parts rather than completely erasing them, but there is a problem in that it is not possible to deal with this.

OBJECTS OF THE INVENTION An object of the present invention is to provide a copying machine that can partially change the copy density setting, thereby making it possible to perform trimming with blurred boundaries, and This makes it possible to copy some parts darker and others lighter.

Structure of the Invention The copying machine of the present invention has a large number of light emitters arranged in a direction perpendicular to the direction of movement of the photoreceptor at a predetermined position before the photoreceptor moves and reaches the developing device, and each of the light emitters or variable light emitting drive means for driving the light emitting amount in a plurality of adjustable stages for each group of a plurality of light emitting units, and the variable light emitting drive for transmitting the light emitting amount designation signal according to the movement timing of the photoconductor and the position of the light emitter. The structure is characterized by the provision of a control means for specifying the amount of light emitted to the device.

Function: In the copying machine of the present invention, the amount of light emitted from the light emitters can be adjusted in a plurality of stages for each light emitter or for each group. Therefore, the amount of light emission can be set in at least two stages: a stage for completely erasing the electrostatic latent image and a stage for incompletely erasing the electrostatic latent image.

Therefore, if you perform a trimmed copy, the parts of the image that will be kept and the i! Since intermediate steps can be provided at the boundaries of image parts, the blurring effect can be made more complete by increasing the number of adjustable steps in the amount of light emitted by the zero emitters that produce the blurring effect.

Further, it is also possible to make a normal copy of a part of the document and to make a light copy of the other part.

Conventionally, it was not possible to change the copy density setting partially, so it was not possible to change the copy density settings for originals with dark and light parts (for example, originals with different densities pasted together, such as a photo pasted on a part of printed matter). ), there was a problem in that if the copy density was adjusted to one side, it would be inappropriate for the other, making it impossible to obtain a satisfactory copy image. Since it is possible to make a dark copy of the light portions of the original, it is also possible to correct local density differences in the original and obtain a copied image with uniform density.

EMBODIMENT OF THE INVENTION Hereinafter, the present invention will be explained in more detail based on the embodiments shown in the drawings. Here, FIG. 1 is a conceptual diagram of the main part configuration of a copying machine according to an embodiment of the present invention, FIG. 2 is a perspective view of an example of a blank lamp, and FIG. 3 is a circuit of an example of a drive means for variable light emission amount of the blank lamp. 4 is a characteristic diagram of the current flowing through the LED, and FIG. 5 is an exemplary diagram of a trimmed image with blurred boundaries.

Note that the present invention is not limited to the embodiments shown in the figures.

FIG. 1 is a conceptual diagram of a copying machine 1 according to the present invention, in which a photosensitive drum 2 is uniformly charged by a charger 3 while being rotated, and is exposed to light by an optical system 4 to form an electrostatic latent image.

Next, the toner image passes under the blank lamp 5, and a toner image is formed in the developing device 6.

The toner image is transferred by a transfer section 8 onto a copy sheet supplied from a paper feed section 7, and the copy sheet with the toner image transferred thereon heads toward a fixing section (not shown).

9 is a cleaning device.

Copying conditions for copying, etc. are set using the operation unit 10.
A control unit 11 centered on a microcomputer controls the rotation of the photosensitive drum 2, the drive of the optical system 4, and the like.

Further, the drive circuit 12 is controlled according to the copying conditions inputted from the operation unit 10, and the LED of the blank lamp 5 is driven.

The blank lamp 5 has an LED of 5m as shown in FIG.
, 5, . ．． ... are arranged so that they are lined up.

FIG. 3 shows the drive circuit 12, in which each L
EDS1.5+, . . . can be driven by being supplied with drive current via the resistor R and transistor T by the LED lighting command signal from the control unit 11, unlike the conventional drive circuit (see FIG. 7). The same is true. When the LED is turned on via the resistor R, the amount of light emitted is sufficient to completely erase the electrostatic latent image.

What should be noted here is that the variable power supply 131°13t...
A drive system for LEDs 5m, 5h, . . . is provided.

The drive system including the variable power supplies 13m, 13b, . , 13+, ,...
When a voltage command is given to LED5., the drive current based on the voltage command is applied to LED5. ．． 5&, . . .

Next, the operation of this copying machine 1 when performing trimmed copying with blurred boundaries will be described.

When data on the trimming area and an instruction to blur the boundary are given from the operation unit 10, the control unit 11 controls the photosensitive drum 2. Charger 3. An electrostatic latent image of the document is formed on the photosensitive drum 2 by controlling the optical system 4 and the like.

In the initial stage when the electrostatic latent image passes directly under the blank lamp 5, all the LEDs 5a and 5+.

, . . . are given an LED lighting command signal, and are caused to emit light by a drive system via a resistor R. The drive current has a distribution like α shown in FIG.

Next, the control unit 11 controls the left and right sections δ1. of the blank lamp 5. For δ5, LE is determined by the system via the resistor R.
D continues to be lit, and the central sections δ2, δ1. δ. For this reason, switch to a drive system using a variable power supply. Then, in the section δ3, the drive current is changed to O during a predetermined boundary period. Also, the interval δ2.
As for δ, an intermediate drive current value is set that connects the drive current value through the resistor R and the drive current value in the section δ3. β shown in FIG. 4 exemplifies the drive current distribution during this boundary period.

At the end of the predetermined boundary period and in the middle period, as shown by γ in FIG. is turned off, and the interval δ2. between them is turned off. δ,
Then, the LED is made to emit light with an intermediate drive current.

In the boundary period between the middle and late stages, contrary to the boundary period between the early and middle stages, the interval δ7. δ1. The drive current of δ1 is gradually increased.

At the final stage, all LEDs are turned on again, as shown by α in Figure 4.
lights up.

In this way, as shown in FIG. 5, a copy image I is obtained in which a trimming copy is made to copy only the image in the center of the original, and the boundary thereof is blurred. is obtained.

As can be understood from the figure, the electrostatic latent image has been erased in the area τ1 corresponding to the initial stage and the area τ5 corresponding to the final stage, so that the copied image has been erased. In addition, areas δ7 corresponding to the left and right sides. The copy image of the portion δ5 is also erased. On the other hand, the copy image ■
. is formed, and a boundary region, namely τ2. τ1. δ2. δ
In the area surrounded by -, the electrostatic latent image is erased in stages, resulting in a blurring effect.

Now, in the above-mentioned trimming copying, the peripheral portion is completely erased, but it is also possible to easily copy this portion in a lighter manner. That is, in the above example, the area τ weight, τ5. In the area surrounded by δ ward and δ5, LF! , D, exposure was performed with a light emission amount sufficient for complete erasure, but instead of this, exposure may be performed with a light emission amount for incomplete erasure. In this case, the drive current is not supplied via the resistor R, All variable power supplies 13a, 136, ・
... supplies drive current to LEDs 5m, 5t, and so on. And area τ3. τ5. The drive current corresponding to the portion surrounded by δh δ may be made smaller than the drive current through the resistor R.

In this case, if the document is dark in the center and light in other parts, the difference in density that exists in the electrostatic latent image caused by the exposure by the optical system 4 will be due to the exposure by the blank lamp 5. The given density difference is canceled out, and as a result, a copied image with uniform density is obtained. Therefore, it will be understood that it is possible to obtain a copy image with uniform density differences from an original document with partial density differences.

Another example is one in which one variable power source is associated with a plurality of LEDs, instead of each individual LED being associated with a variable power source. In this case, the number of variable power supplies can be reduced and the configuration can be made into an IVTM.

Another example is one in which the LED is controlled to turn on at an intermediate stage of full lighting 5 and completely turned off using a variable power source, and the resistor R and transistor Tr are omitted.

Effects of the Invention According to the present invention, a large number of light emitters are arranged in a direction perpendicular to the moving direction of the photoreceptor at a predetermined position before the photoreceptor moves and reaches the developing device, and the light emitters are arranged individually or in plural numbers. a variable light emission drive means for adjusting the light emission quantity in a plurality of stages for each group of light emitting units; and a light emission quantity specifying signal is applied to the light emission quantity variable drive means according to the movement timing of the photoreceptor and the position of the light emitter. A copying machine is provided which is characterized by being provided with a light emitting amount designation control means, which makes it possible to partially change the copy density, so that it is possible to perform trimming copying with blurred boundaries,
It becomes possible to copy part of an image with normal density and the other part with light color. Furthermore, it is also possible to form a copy image with uniform density from a document having partially different densities.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of the main parts of a copying machine according to an embodiment of the present invention;
Fig. 2 is a perspective view of an example of a blank lamp, Fig. 3 is a circuit diagram of an example of a drive means for variable light emission amount of a blank lamp, Fig. 4 is a characteristic diagram of the current flowing through the LED, and Fig. 5 is a diagram with blurred boundaries. FIG. 6 is a plan view showing the correspondence between the photosensitive drum and the blank lamp, FIG. 7 is a drive circuit diagram of a conventional blank lamp, and FIG. 8 is a characteristic of the drive current during conventional trimming copying. FIG. 9 is a plan view of an example of a cropped and copied image. (Explanation of symbols) Machine... Copy machine 2... Photosensitive drum 5...
・Blank lamp 5m, 5I, ... LED 6... Current@, instrument 11... Control section 12...
- Drive circuits 13a, 13b, ~...variable power supply.

Claims (1)

[Claims] 1. A large number of light emitters are arranged in a direction perpendicular to the moving direction of the photoreceptor at a predetermined position before the photoreceptor moves and reaches the developing device, and the light emitters emit light individually or in groups of a plurality of light emitters. A light emitting amount variable drive means for driving the amount of light to be adjusted in a plurality of stages, and a light emitting amount designating control means for supplying a light emitting amount designation signal to the light emitting amount variable drive means in accordance with the movement timing of the photoreceptor and the position of the light emitter. A copying machine characterized by: