JPS6310173A - Electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To delicately execute positioning of a part which is brought to limited copying, by providing an optical eraser moving mechanism for moving and fixing an optical eraser for annihilating a charge of a non-recorded part on a photosensitive body, in the direction orthogonal to a scanning direction. CONSTITUTION:In an eraser moving mechanism (EM), wires 21, 22 are fixed to both ends of sub-erasers 17, 18, and each of them is wound and fitted to driving shafts of stepping motors 23, 24. A position of sliders 20a, 20b which have been provided side by side in the direction B orthogonal to the scanning direction is detected by a position detecting means 26. Based on its detected information, a control device 25 determines which LED is to be lighted, outputs an LED lighting control signal and a driving pulse signal to the sub-erasers 17, 18 and the stepping motors 23, 24, respectively, and moves the sub-erasers 17, 18 in the direction B orthogonal to the scanning direction. In this way, positioning of the end edge of a charge annihilation area on a photosensitive body to the B direction is executed with high accuracy, and desired limited copying can be executed easily.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention includes a scanning device and an imaging device for forming an electrostatic latent image of a document on a photoconductor, and includes a scanning device and an image forming device that extend from a charging device to a developing device. By providing an optical eraser along the way that selectively activates a plurality of light irradiation units arranged in a direction perpendicular to the scanning direction of the scanning device to erase the electric charge on the non-recording portion of the photoreceptor, the desired image of the original can be achieved. This invention relates to an electrophotographic copying machine that is capable of limited copying of only a portion.

[Conventional technology]

In the above-mentioned electrophotographic copying machine, the optical eraser composed of a plurality of light irradiation units is generally composed of an LED (light emitting diode) array or a combination of one light source and a light shutter array. , which was fixed in position in a direction perpendicular to the scanning direction by the above-described scanning device.

Then, appropriately selected LEDs from those LED arrays are
By turning on D or by operating a suitably selected optical shutter of the optical shutter array, the charges on a predetermined portion of the photoreceptor in a direction perpendicular to the scanning direction by the scanning device are extinguished, and the other It was constructed so that only the electrostatic latent image formed in the area was visualized by a developing device and recorded on the recording paper (for example, Japanese Patent Laid-Open No. 58-116556, 60-4962).

[Problem that the invention seeks to solve]

However, in the case of the above-mentioned conventional configuration, the charge extinction area on the photoreceptor is determined only by whether or not each light irradiation section is activated. The minimum amount of movement in the direction corresponds to the distance between the light irradiators, and it has been impossible to position the portion to be copied in a direction perpendicular to the scanning direction of the scanning device more finely than the distance between the light irradiators.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to enable more precise positioning of a portion to be copied in a limited manner.

[Means for solving problems]

A characteristic configuration of the electrophotographic copying machine according to the present invention is that a plurality of light irradiation units, which are provided on the way from the charging device to the developing device and are arranged in a direction perpendicular to the scanning direction by the scanning device, are actuated selectively. An optical eraser moving mechanism is provided that moves and fixes an optical eraser for erasing charges in the upper non-recorded portion in a direction perpendicular to the scanning direction.

[For production]

In other words, if the optical eraser is moved by the optical eraser moving mechanism, the charge extinction area on the photoreceptor, which is determined by selectively operating the plurality of light irradiation parts that make up the optical eraser, can be It can be moved continuously in a direction perpendicular to the scanning direction.

Therefore, it is now possible to accurately determine the position of the portion to be copied in a direction perpendicular to the scanning direction, regardless of the spacing between the light irradiation parts constituting the optical eraser.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 2 is a sectional view schematically showing an electrophotographic copying machine.

A manuscript (M
) is irradiated by an exposure lamp (2), and the reflected light from the irradiated portion of the document (M) is reflected by an imaging device (
3), a photoreceptor drum (4) which is an example of a photoreceptor.
It is configured to be projected onto the top.

The exposure lamp (2), first mirror (3b), etc. that constitute the scanning device (S) are moved to the right in the figure by the drive of the main motor (D) via a clutch (not shown) to scan the original (
M). Moreover, the second mirror (3c) and the third mirror (3d) have an image formation value! (3)
In order to maintain a constant imaging optical path length by the scanning device (
The same main motor (D) at half the speed of movement of S)
It is configured to move to the right in the figure when driven by .

When the original (M) is scanned by this scanning device (S), the reflected light with an intensity corresponding to the density of the original & (M) is rotated clockwise in the figure by the drive of the main motor (D). Images are sequentially formed on the uniformly charged photoreceptor drum (4), and the surface potential of the photoreceptor drum (4) is attenuated according to the intensity of the images. As a result, an electrostatic latent image is formed on the photoreceptor drum (4).

Around the photoreceptor drum (4), there is a charging device (5) that uniformly charges the surface of the drum, and an imaging device (3) that attaches toner to an electrostatic latent image formed by projection and imaging. A developing device (6) that converts the developed image to a recording paper (P) and a transfer separation device (7) that separates the recording paper (P) from the photosensitive drum (4), which transferred the developed image. A cleaning device (8) removes excess toner adhering to the surface of the photoreceptor drum (4) after transfer, and a cleaning device (8) that removes excess toner adhering to the surface of the photoreceptor drum (4) after transfer.
) is provided with a main motor (9) etc. for extinguishing the electric charge on the main motor (9).

In the developing device (6) of this electrophotographic copying machine, the charge did not completely disappear in the area on the photoreceptor drum (4) where the charge was present, that is, the amount of reflected light reaching was small or zero. , the electrostatic latent image is developed by a so-called regular development method in which toner is attached to a portion corresponding to the image area of the document (M).

On the other hand, two types of recording paper (P) of different sizes are stored in separate paper feeding capacity centers (10a) and (10b). Then, when there is a print request command, the recording paper (P) of the specified size is taken out one by one by the pickup roller (lla or 11b), and the electrostatic latent image is formed on the photoreceptor drum (4). The sheet is configured to be fed into a transfer separation device (7) by a conveyance device (12) in synchronization with the formation. With this, the manuscript (M)
The developed image is transferred onto the recording paper (P).

After that, the recording paper (P) is separated from the photoreceptor drum (4).
) is transferred to the heating fixing device (14) by the conveying device (13).
After the unfixed image carried on the surface is fixed, a pair of ejection rollers (15a) and (15b)
) so that it is discharged onto a tray (16) outside the copying machine.

In addition, in this electrophotographic copying machine, a developing device (6)
A pair of sub-erasers (17) and (1B), which are examples of the optical eraser (E) according to the present invention, are provided in front of the. The pair of sub-erasers (17) and (18) are provided to perform limited copying of only a desired portion of the original (M). In other words, it is possible to obtain a copy of only the part where necessary information exists from a manuscript (M) such as a newspaper, which contains various types of information.

As shown in FIG. 2, these pair of sub-erases (17) and (18) are arranged in the direction (B direction in the figure) perpendicular to the scanning direction (A direction in the figure) by the scanning device (S). Multiple light emitting diodes lined up (hereinafter abbreviated as LED)
(17a) and (18a), and has a length approximately equal to the length of the photoreceptor drum (4). And those plural L E D (17a), (
By lighting appropriately selected LEDs 18a), the charges on the surface of the photoreceptor drum (4) in the portions irradiated by those LEDs (17a) and (18a) are extinguished, and the other LEDs are turned on. It is configured so that only the electrostatic latent image formed on the portion is visualized by the subsequent developing device (6).

In addition, these pair of sub-erasers (17) and (18
) is configured to be moved and fixed in a direction perpendicular to the scanning direction (direction B in the figure) by each optical eraser moving mechanism (EM) described later. In other words, the area where charges are eliminated on the photoreceptor drum (4) by operating the sub-erasers (17) and (18) is as follows:
This sub eraser (17
), (18) are fixed, they L E
D The distance between (17a) and (18a) (in this example, it is [5fi]) or less, the edge of the charge extinguishing area of the photoreceptor drum (4) in the direction perpendicular to the scanning direction is Difficult to position.

Therefore, by moving these sub-erasers (17) and (18) in a direction perpendicular to the scanning direction, the edge of the charge annihilation area can be accurately positioned in this direction, and desired limited copying can be easily performed. It is composed.

The portion to be limitedly copied is arbitrarily set by the user. There are various configurations as the setting means, but for example, as shown in FIG. 4, a pair of horizontal and vertical rails (19) and (20) along the edge of the document table (1), Two sliders (19a) and (1) slidably fit into both rails (19) and (20).
9b), (20a), and (20b) are provided, and each of these sliders (19a), (19b), and (2
By appropriately moving 0a), (20b), the vertical and horizontal coordinate values (x+), (xt), corresponding to the four sides of the limited copy area in the plane coordinates corresponding to the document table (1) are obtained.
This is done by setting (y+) and (Vz). Note that (27) in the figure is an operation panel.

In addition, for example, when using an automatic document feeder that inverts a document (M) with the recording side facing up and feeds it onto the document table (1), a document tray that holds the document (M) with the recording side facing upward may be used. It is possible to provide the aforementioned rails and sliders.

In addition, as shown in FIG. 1, an optical eraser moving mechanism (EM) that moves and fixes the sub-erasers (17) and (18) separately in a direction orthogonal to the scanning direction includes both sub-erasers (17), Wires (21) and (22) fixed at both ends of (18), and their respective separate wires (
21) and (22) are wrapped around the drive shaft.
It consists of two-pin motors (23), (24), a control device (25) that controls the driving of these stepping motors (23), (24), and the like.

The positions of the two sliders (20a) and (20b) arranged in a direction perpendicular to the scanning direction are detected by a position detection means (26) such as a potentiometer or a linear encoder, and the detected information is sent to the control device (25). ) is entered. The control device (25) determines which LEDs (17a), (18a) to turn on based on the detection information, and turns on the sub-erasers (17), (18).
) is configured to output an LED lighting control signal to the motors (23) and (24), and drive pulse signals to the stepping motors (23) and (24).

The pair of sub-erasers (17) and (18) described above are normally in the initial position shown in FIG. 5(A). In this state, for example, the two sliders (20a) mentioned earlier,
(20b), the two coordinate values (
Consider the case where y+) and (yz) are set.

The sub-eraser (17) on the upper side in FIG. 1 moves to the right side in the figure by driving the stepping motor (23).

The amount of movement at this time is 11 as shown in FIG. 5(a). Further, the sub-eraser (18) on the lower side in the figure moves to the left side in the figure by driving the stepping motor (24). The amount of movement at this time is [12] shown in FIG. 5(a).

In this state, two sub-erasers (17) and (18
) is located at the position shown in FIG. 5(0).

Then, by the LED lighting control signal from the control device (25) mentioned above, the LED shown by hatching in the figure is activated.
(17a) and (18a) are lit.

As a result, the charge on the surface of the photoreceptor drum (4) in the area irradiated by them disappears, and recording is not performed in this area.

The movement range of the two sub-erasers (17) and (18) is at least as large as each L E D (17a) and (1
8a) Only the spacing between them is sufficient. That is, for example, in FIG. 5(A), when the coordinate value (y3) shown by the two-dot chain line is set, the sub eraser (17) on the upper side in FIG.
is moved to the right by [A'3], and as shown in Fig. 5 (
L E D (17a) displayed with bars/tings on (b)
, (18a) plus the upper sub-eraser (17)
This is because it is sufficient to turn on two more LEDs (17a). Also, a pair of sub-erasers (17),
(18) can move, so L E D (17a)
, (18a) itself is somewhat larger, the same accuracy can be obtained.

On the other hand, regarding the scanning direction, L E D (17a) and (18a), which are not displayed with hunting in FIG.
) is the floor plan of the timing corresponding to two coordinate values (Xυ, (x=) set in the horizontal direction of the document table (1) when scanning the document (M) with the scanning device (S). By outputting the LED lighting control signal so as to turn on the external light, the charge on the surface of the photosensitive drum (4) in the corresponding portion is eliminated.

Then, the sub-eraser (17
) and (18), a copy of only the hatched portion in FIG. 4 can be obtained.

Note that the optical eraser (E) is not only composed of a plurality of LEDs (17a) and (18a) like the pair of sub-erasers (17) and (18) described in the previous embodiment, but also one It may be composed of a tubular halogen lamp and a plurality of optical shutters arranged in a direction perpendicular to the scanning direction, and each of these L E D
(17a), (18a), or a combination of one optical shutter and a corresponding halogen lamp part is called a light irradiation part (IP).

In the previous embodiment, the optical eraser (E) includes a pair of sub-erasers (17) and (18) having approximately the same length as the photoreceptor drum (4). Instead, a pair of sub-erasers each having a length approximately half the length of the photoreceptor drum (4) are arranged so as to overlap each other by a predetermined length approximately at the center of the photoreceptor drum (4). It's okay. Further, as the optical eraser (E), only one sub-eraser may be provided, or three or more sub-erasers may be arranged in parallel in a direction perpendicular to the scanning direction, and the specific configuration can be changed as appropriate. .

Furthermore, in addition to the optical eraser (E) according to the present invention, a pair of erasers whose positions are fixed in a direction perpendicular to the scanning direction are provided at portions corresponding to both ends of the photoreceptor drum (4) in the longitudinal direction. The eraser may also be configured to serve as the optical eraser according to the present invention.

Furthermore, the specific configuration of the optical eraser moving mechanism (EM) can also be changed as appropriate. For example, instead of the wires (21) and (22) described in the previous embodiment, the sub-erasers (17) and (1
8) and the stepping motors (23) and (24) may be linked. Further, the optical eraser moving mechanism (E?I) may be configured to be connected to a manual operating tool to manually move the optical eraser (E).

Regarding the position where the optical eraser (E) is applied, even after the electrostatic latent image is formed on the photoreceptor drum (4),
Alternatively, it may be in a state before the electrostatic latent image is formed, and in short, at any position on the way from the charging device (5) to the developing device (6), the electrostatic latent image may be acted on. You may let them.

Further, instead of the photoreceptor drum (4), a belt-shaped photoreceptor stretched between a pair of rollers may be used, and these will be referred to as photoreceptors (4). As for the scanning device (S), instead of the type in which the exposure lamp (2) and the first mirror (3b) move as in the previous embodiment, each mirror (3b) to (
3e) may each rotate around different axes, or the exposure lamp (2) may be fixed and the document table (1) may be moved.

〔Effect of the invention〕

As described above, in the electrophotographic copying machine according to the present invention, by moving the charge erasing area on the photoconductor by the optical eraser in a direction perpendicular to the scanning direction, the positioning of the limited copy portion in this direction can be performed with precision. (Since it can be done, even if the distance between the light irradiation parts is large,
It is now possible to accurately edit and copy a desired portion of a manuscript.

In particular, when a pair of left and right optical erasers is provided along the direction orthogonal to the scanning direction, and a separate optical eraser moving mechanism is provided for each pair of optical erasers, the positioning of both sides of the portion to be limitedly copied is performed separately. This can be performed with high precision, and the above-mentioned effects can be further enhanced.

[Brief explanation of the drawing]

The drawings show an embodiment of an electrophotographic copying machine according to the present invention, in which FIG. 1 is a schematic diagram of the optical eraser moving mechanism, FIG. 2 is a schematic diagram of the electrophotographic copying machine, and FIG. 3 is a perspective view of the optical eraser. Figure 4 is a plan view of the document table, Figures 5 (a) and (b) are schematic plan views of the optical eraser, and Figure 5 (a) is the initial position.
FIG. 5 (r+) shows the position after movement. (4)...Photoreceptor, (5)...Charging device, (6)...Developing device, (S)...
Scanning device, (M)... Original, (E)...
・Optical eraser, (IP)...Light irradiation part, (EM
)...Optical eraser movement mechanism.

Claims (1)

[Claims] A scanning device and an imaging device are provided for forming an electrostatic latent image of a document on a photoreceptor, and a plurality of images are arranged in a direction perpendicular to the scanning direction by the scanning device on the way from the charging device to the developing device. In an electrophotographic copying machine equipped with an optical eraser that selectively operates a light irradiation section to erase electric charge on a non-recorded portion on a photoconductor, the optical eraser is moved and fixed in a direction perpendicular to the scanning direction. An electrophotographic copying machine equipped with an eraser moving mechanism.