JPS5875175A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To clearly form a boundary of a picture forming area and a picture non-forming area, by providing a mask means which moves by synchronizing with movement following a movement of a photosensitive body of both the areas. CONSTITUTION:In case when a polarized plate is used as a mask member, mask members 10c, 10d are constituted so that the polarizing directions fall at right angles with each other. An area 19 shown by oblique lines shows a part where polarized plates 10c, 10d are superposed, and the polarized plates 10c, 10d are constituted so as to be varied independently by a control means in the direction as indicated with an arrow, by which it is possible to set continuously and optionally the area where the polarized plates 10c, 10d are superposed.

Description

[Detailed description of the invention] This is a 1 Jla electrophotographic equipment Kll.

BACKGROUND ART Conventionally, in an electrophotographic apparatus, in order to prevent the non-image forming area of a photoreceptor from becoming one area, the non-image forming area is irradiated with light to erase the electrical charge or prevent charging. The boundary between the image forming area and the non-image forming area moves in the direction of movement as the photoreceptor moves, but conventionally, the boundary between the image forming area and the non-image forming area moves in the direction of movement. Turn on the lamp at the same time or when you leave this area.

Or, by turning it off, the two areas are partitioned. However, in this method, since the rise and fall of the lamp are relatively slow, it is not possible to make the boundary sharp enough, and the light is emitted near the boundary Kt of the image forming area. There are disadvantages in that the image is erased in a complicated manner, or that the vicinity of the boundary of the non-image forming area is not provided with sufficient light and is visualized.

The main purpose of the present invention is to solve the above-mentioned disadvantages.

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

Trim-shaped photoreceptor 1 rotating in the direction of the arrow in FIG.
a. Its structure consists of a conductive layer and a photoconductive layer,
First: it is charged by the discharger 2. Next, the original image '4 on the document table 3 is illuminated from below by the illumination lamp 5, and the image is reflected on the photoreceptor 1 through the optical system of the reflecting mirrors 6 and 7 and the lens 8, resulting in the above-mentioned image. An electrostatic latent image is formed on the photoreceptor. At this time, in order to erase the electrostatic latent image on the image forming area on the photoreceptor 1, light is irradiated from the light source 9, but the light from the light source 9 is directed to the image forming area by the mask member 10m. Part K11l due to superposition of 10b
covered. The electrostatic latent image of the image forming area on the photoreceptor 1 thus formed by erasing the electrostatic latent image of the image forming area is then converted into a developed image by entering the developer 11, and then transferred by the transfer unit 12. The image is transferred onto paper 13. Thereafter, the image is transferred to the transfer paper 13 and fixed by a fixing source (not shown), and the transfer paper 13 is discharged outside the acid storage. On the other hand, the photoreceptor 1 is
The cleaning blade 14 wipes off the toner remaining after the second transfer, and the above cycle is repeated again.

FIG. 2 is a partial diagram showing a mechanism for controlling the light from the light source 9 using a mask member to control division of the image forming area and non-forming area on the photoreceptor. corresponds to In the figure, the light source 9 is either a point light source with a sufficient number to uniformly illuminate the entire width of the photoreceptor 1, or a line light source with a sufficient irradiation width to illuminate the entire photoreceptor 1 in the axial direction. It is. The light source 9 is installed in the light source frame 15 so as to be substantially parallel to the photoreceptor IK in order to make the illuminance uniform on the surface of the photoreceptor 1. Also, the light source frame 15
A slit 18 is provided so that the irradiation width of the light 16 matches the irradiation width d of the exposure light 17 of the original image.

The mask members 10m and 10b move onto the optical path of the control light 16 when necessary to mask this light to the image forming area. The mask members 10m, . . . 10b block the light 16 from reaching the photoreceptor l by overlapping them. Therefore, the image remains without being erased. However, the light 16 is transmitted where the above-mentioned members do not overlap, and the charges on the photoreceptor l are erased. As a result, unnecessary images will be deleted.

FIG. 3 is a diagram showing overlapping of mask members. In this embodiment, an example in which a polarizing plate is used as a mask member will be shown in the following description.

In FIG. 3(1), the mask members Roe and 1°d are polarizing plates configured such that their polarization directions are perpendicular to each other, and a shaded area 19 indicates a portion where the polarizing plates overlap. The polarizing plates 10C and 10d are indicated by the arrow O shown in the figure.
The direction can be changed independently by a control means (not shown) K, which allows the overlapping region 19 of the polarizing plates to be continuously set arbitrarily. .

FIG. 3(2) shows an example in which an electrostatic latent image is formed only in an arbitrary region of the photoreceptor. The figure shows a polarizing plate 10e.

This is a view of how the Rods are stacked together from above in FIG. 3(1). The light 16 has a polarizing plate of 10 cm and 1 Od overlap)
The matching portions are completely closed, or at least transmit light to the extent that the photoconductive layer on the surface of the photoreceptor is not electrically conductive, and therefore the electrical charges on the photoreceptor are not erased. On the other hand, the single polarizing plate portions (non-overlapping portions) on both sides transmit at least enough light 16 to completely erase the charges on the surface of the photoreceptor.

Therefore, as shown in the figure, an electrostatic latent image 22 (indicated by a positive charge) remains on the photoreceptor 1 in the area exposed to the light, and the latent image is erased in the area through which the light is transmitted.

Note that the configuration of the polarizing plate is such that if the light can produce K11l light to an extent that the charges on the photoreceptor are not erased by the light,
The polarization directions do not need to be orthogonal to each other.

Furthermore, the mask member is not limited to a polarizing plate, but may be any other member as long as the above-mentioned functions and effects can be achieved through the superposition K. That is, the mask member has the function of producing at least a light-transmitting effect to the extent that it does not erase the electrical charges on the photoreceptor when superimposed, and when used alone, it has the function of transmitting enough light to erase the electrical charges. Any material may be used as long as it is a member. For example, in addition to a polarizing plate, (a) depending on the spectral sensitivity of the photoreceptor, even if you superimpose a filter that divides the wavelength range so that the amount of light is the same, it will not work, and (b)
A material having a large absorption coefficient for light may be used. Furthermore, (c) even if the polarizing plate and the liquid crystal are superimposed and the orientation of the liquid crystal is changed, the effect of the above-mentioned light transmission alignment can be obtained.

FIG. 4 shows the entire area A of the original image. In the figure, the shaded nine areas (areas where abed KS has passed) represent the necessary image area B, and the other areas (white areas) represent unnecessary image areas.

The original image mA advances in the direction of the arrow and is sequentially scanned with the slit exposure width.
The width of 1 or the distance between a and 4 (between b and c) corresponds to the length.

FIG. 5 is a diagram showing an example of the operation of the polarizing plate in rounding to obtain the required image area B from the original image mA in FIG. Figure 5 (1
) to (4).
This is a cross-sectional view taken at the overlapping part of 0f (line V-v'), and the figure on the right shows how the polarizing plate controls the irradiation area of the light 16 with respect to the exposure light of the original image on the photoreceptor IK. FIG. In the diagram on the left side of FIG. 5, the solid line and dotted line along the drum-shaped photoreceptor IK are the image (2) to be formed from the assumed original image as shown in FIG. 4 on the surface of the photoreceptor 10, and the arrow It advances on the photoreceptor in synchronization with the rotation in the direction. In image I, the solid line portion corresponds to the necessary image area K (area B in FIG. 4), and the dotted line portion corresponds to the unnecessary image area K (white area in FIG. 4). Also, in the figure on the right, the area 23 surrounded by the dotted line
indicates the irradiation area of the light 16 with respect to the exposure light 17 of the original image.

As shown in FIG. 5 (1) K, the original image is scanned and the position of the tip a-b (boundary between the image forming area and non-forming area) of the required image area in the image 2 is the irradiation area 2 of the light 16.
3, the polarizing plates 10...10f are completely out of the optical path of the light 16. As a result of this K, the light irradiation area 23 on the photoreceptor 1 receives the light 16 over the entire surface, and the charges in the area are erased. Therefore, all electrostatic potential in the area from the tip of image I to position a-b is erased,
When trying to obtain a copy as shown in Fig. 4, the area corresponding to the above area will be blanked out and no image will be formed. At 9 o'clock when the light reaches the light irradiation area 23, it begins to descend in the direction of the arrow shown in FIG. 5(2). Next, the polarizing plate 10
・10f has 16 lights completely! ! It descends until it breaks and then stops. This state is maintained until the position of the rear end ed (boundary between the image forming area and non-forming area) of the necessary image area indicated by the image IK reaches the light irradiation area 23. Therefore, in the light irradiation region 23, the light 16 is prevented from being irradiated to the region corresponding to the overlapping portion 24 of the polarizing plates 10e and 10f, and the electrostatic latent remains in the region without being erased. On the other hand, in the irradiation area 23, the area corresponding to the non-overlapping portion of the polarizing plate is irradiated with the light 16, and the electromagnetic potential in the area O is erased. Therefore, when attempting to obtain a copy as shown in FIG. 4, an image is formed covering area B indicated by diagonal lines.

When the position c-d shown in one image IK further advances and reaches the light irradiation area 23, as shown in FIG. 5(3)K,
While the polarizing plates 10e and 10f remain in an overlapping state, their upper ends begin to descend in the direction of the arrow in synchronization with the progress of the position c-d, and eventually descend to a position where they are completely out of the optical path of the light 16 and stop. . The above position is maintained until the image I completely passes through the light irradiation area 23, that is, until the scanning of the original image is completely completed. Therefore, the shadows in the area from position ed to the rear end of the image are erased, and the area of the copy corresponding to the above area includes the area from the above-mentioned tip to position a-
Similar to the bt area, no image is formed at all.

When the scanning of the original image is completed, the polarizing plate ion 10b
It rises in the direction of the arrow in Figure (4), and in Figure 5 (1) K.
It returns to the nine yuan position.

FIG. 6 is a perspective view showing an embodiment of the polarizing plate Enit, which has two polarizing plates arbitrarily overlapped and a control means for controlling the polarizing plates. The right end of the polarizing plate 24 on the front side is wound up by a spool 25 on which back tension is applied, and the back tension of the spool is provided by a spring or the like.

On the other hand, at the left end (MO position in the figure) K of the polarizing plate 24, a transparent film 26 is continuously connected. installed in a parallel position. A gear 28 is installed on the rotating shaft of the spool 27, and this gear 28
8 meshes with a gear 29 attached to the rotating shaft of the motor 30. The set position of the polarizing plate 24 is determined by the amount of rotation of the motor 30.

Similarly, another polarizing plate 31 whose polarization direction is perpendicular to that of the polarizing plate 24 is arranged parallel to or close to the polarizing plate 24 . The left end portion of the polarizing plate 31 is wound up by a spool 32 having the same configuration as the spool 25 described above. On the other hand, the right end of the polarizing plate 31 (in the figure,
At position N) K, the transparent film 33 is connected continuously in the same way as above, and another spool 34 for winding this transparent film 33 is installed in parallel at a position facing the spool 32. . A gear 35 is installed on the rotating shaft of the spool 34, and the third gear 35 is attached to the motor 37 and meshes with the ninth gear 36. With the above configuration, the setting position of the polarizing plate 31 is determined by the amount of rotation of the motor 37.

When the polarizing plate 24 is pulled out from the spool 25 to the MO position in the figure, and the polarizing plate 31 is further pulled out from the spool 32 located on the opposite side of the spool 25 to the N position in the figure, the polarizing plate 24. MN where 31 overlaps
The portions of the polarizing plate other than those described above transmit enough light to erase the charges on the photoreceptor.

Next, a mechanism (hereinafter referred to as a monitor mechanism) K for selecting a necessary image area will be explained.

FIG. 1 shows an embodiment of an electronic copying machine having a monitor mechanism. The monitoring mechanism includes an illumination lamp 38° lens 399 reflection mirrors 40, 41. Screen 42. Indicator X, ・X, ・Y
It is composed of l, y, etc. When the original table 3 on which the original image 4 is placed is positioned above the illumination lamp 38, it is illuminated and the nine images are projected onto the screen 42 through an optical system consisting of a lens 391 and reflecting mirrors 40 and 41.

From me on this screen 42, indicators X1, X, Yl
- The required image area is selected by Y. Among the above-mentioned indices, the indices X and Xt are used to select the length of the required image area (between a-4 or between b-c in FIG. 4).

The position signals selected from the indicators X and XtK are transmitted to the control means for controlling the vertical movement of the polarizing plate shown in FIG. 5 mentioned above. The index Y,・Y, is the width of the required image area (
(a-4 or de-e in FIG. 4) is selected. A position signal of the width of the region selected by the index Y1·Y is transmitted to a control means for setting the overlapping position of the polarizing plates.

Next, a positioning means having these indicators and selecting a necessary image area will be explained in detail with reference to an embodiment. In Fig. 7, the required image area of the original image 4 projected onto the screen 42 (the diagonal area shaded by S in abed) is the index button X+ that can be moved arbitrarily on the index rails 43 and 44.
' Selected by Xt, Yl, and Y. The position signal of the index data X, which selects the required image area length (a-4) on the index rail 43, is determined by the potential meter PMX from the reference line Xs on the index rail 43 as a voltage drop value or resistance. detected as a value and sent to the AD converter AD
X, is converted into a digital signal and sent to the coincidence circuit CC1.
sent to. On the other hand, the position signal of the photoconductor 45, which rotates in the direction of the arrow in synchronization with the drum-shaped photoconductor 45 and is detected from the four-wheeled plate 46 as a clock pulse by an optical or magnetic device, is also transmitted via the pulse counter PCf. and is sent to the coincidence circuit CC. This matching circuit CC3 uses the position signal of the photoreceptor 45 and the previous index button x, I.
/c is compared, and if they match, a motor control circuit MCXK signal is sent. This signal causes the motor control circuit MCX to operate, and the motor M operates to operate the polarizing plate 1.
Move 0g and 10h in the X-axis direction. Similarly, the position signal of index button X is the potential meter PMX!
, the coincidence circuit CC! via the AD converter ADL! sent to. When the above signal and the signal from the clock plate 46 match, the motor M operates during running, and the polarizing plates 10g to 10h move to predetermined positions in the X-axis direction.

Index button Y to select the width of the required image area (between a and b)
, the position signal of the potential meter.

PMY is detected as a voltage drop value or resistance value from the reference @Ys on the index rail 44, and is converted into a digital signal by an AD converter ADY. This digital signal is further transmitted to the motor control circuit MC? Sent to Y.
It is converted into a pulse and operates a pulse motor M. As a result, by the operation of this pulse motor, 10g of polarizing plate
moves to a predetermined position in the Y-axis direction. Similarly, the position signal of the index button Y is the digital meter PMY*
.

The pulse motor M is operated via the AD converter AD My-motor control path MCY, and the polarizing plate 10h is moved in the Y'-axis direction.

As described above, the original image [4 required image area a] is placed on the photoreceptor 45.
A corresponding electrostatic latent image of bcdK, l bl at dl, is formed.

Next, regarding the movement of the mask member for controlling the length direction of the image area, other embodiments other than the example shown in FIG. 5 will be described in detail.

FIG. 8 shows another example of the operation of a polarizing plate as a mask member. The configuration of each part is the same as that in Figure 5, but the polarizing plates in Figure 5 are of the simultaneous movement type in which they overlap and move up and down together, whereas in this example, each polarizing plate moves up and down together. It is characterized by being an alternating movement type that moves alternately.

First, as shown in tsB diagram (1)K, the position a- of the tip of the required image area in the image IK to be formed from one original image is
Until b reaches the irradiation area 23 of the light 16, one of the polarizing plates 10eFi is completely out of the optical path of the light 16. However, the other polarizing plate 10f is inserted into the optical path in such a way as to completely block the light 16. Next, when the position a-b advances and reaches the light irradiation area 23Vc, as shown in FIG. begins to descend. Next, polarizing plate 10
e descends until it completely overlaps the other polarizing plate 10f and the light irradiation area 23, and then stops. This state is
The position e-d of the rear end of the required image area in image (2) is maintained until it reaches the light irradiation area 23. Above position e-
When d reaches the above region 23, as shown in FIG.
The upper end of the other polarizing plate 10f begins to descend in the direction of the arrow in synchronization with the progress of ed. The polarizing plate 10f completely deviates from the optical path of the final light 16 and stops. This state is maintained until the scanning of the original image is completed, and then the polarizing plate 10
e and 10f both rise in the direction of the arrow in Figure 8 (4),
Return to the position shown in Figure 8.

From the above, it can be understood that, as in the operation example shown in FIG. 5, an image is obtained by excluding the peripheral part of the painting of Nyomon Genji in FIG. 4'. Moreover, in this example, it is not necessary to move two polarizing plates at the same time, so it is easier to synchronize the ends of the polarizing plates and the progress of the image. In addition, the polarizing plate 10e
- 10f may be operated in the reverse order of top peeling.

FIG. 9 shows still another example of the operation of the polarizing plate, and the configuration of each part is the same as that in FIGS. 5 and 8. This example is characterized by being a one-sided moving type in which one of the polarizing plates is always fixed on the optical path of the light 16 and only the other polarizing plate moves.

In FIG. 9, the polarizing plate 10f is fixed so as to completely cover the light 16. First, as shown in Figure 9 (1) k,
The tip position a-b of the required image area in the image IK to be formed from the original image is completely out of the optical path of the light 16.

Next, when the position a-b advances and reaches the light irradiation area 23, as shown in FIG. It begins to descend in the direction of the arrow. Subsequently, the polarizing plate 10e descends until it completely overlaps the other fixed polarizing plate 10f and the light irradiation area 23, and then stops. This state is maintained until the position e-d of the rear end of the required image area in the image t< reaches the light irradiation area 23. When the following position c-d reaches the light irradiation area 23, one of the ten polarizing plates descends in the direction of the arrow in synchronization with the progress of the position e-d, as shown in FIG. 9 (3). start. The polarizing plate 10 eventually leaves the optical path of the light 16 completely and stops. This state is maintained until the original scanning is completed, and then the polarizing plate 10
・ increases by 1 in the direction of the arrow in Figure 9 (4), and increases to Figure 9 (1)
Return to position.

From the above, similarly to the operation examples shown in FIGS. 5 and 8, it is possible to obtain an image of the area of the original image as shown in FIG. 4, with the peripheral portion omitted. Furthermore, in this example, only one polarizing plate moves, so the structure of the means for controlling movement is simplified. Note that, contrary to the first example, the polarizing plate 10e is fixed, and the polarizing plate 10f is fixed.
may be moved.

Next, a method for obtaining an image having a shape opposite to that shown in FIG. 4 will be explained in detail.

FIG. 10 shows an unnecessary image area C surrounded by efgh and a necessary image area indicated by diagonal lines in the original image 47. The original image 47 advances in the direction of the arrow and is scanned sequentially with the slit exposure width between e and f (
h-g) is the width K of the unnecessary image area C, and -h (f-
g) is adjusted to the length.

FIG. 11 is a diagram showing how polarizing plates are stacked to obtain the required image area as shown in FIG. 10.

FIG. 11 (1) The polarizing plates 101 and 10j are configured such that their polarization directions are perpendicular to each other, and the polarizing plate 10 has a polarizing plate 10 that is connected to the upper polarizing plates 101 and 10j, respectively, and the polarizing plates 101 and 10j. The directions are orthogonal. For example, if the diagonal lines in the figure are the polarization directions, polarizers 1oi and 10, and 10j and 10, and 1G1
and 10j have their polarization directions perpendicular to each other.

That is, the polarizing plate 10 is configured such that the polarization directions are different (orthogonal) on the left and right sides of the center 48 (dotted chain line). In the figure, the area 49 where the diagonal lines intersect
50 are polarizing plates 101 and 10k and IOJ and 1, respectively.
This is the superimposed part on 0.

FIG. 11(2) shows an example in which an electrostatic latent image is formed only in an arbitrary area on a photoreceptor according to the principle of the present invention. The figure shows the polarizing plates 10i, 10j, and their electrical connections to 10 as seen from above in Figure 11 (1). Third
Figure (2!Similar to the example of J, polarizing plate 101 and 10k or 1
The overlapped portions of G, J and 10 completely transmit the light 16 of the image area, or at least emit light of I/% KlI without erasing the charges on the surface of the photoreceptor. On the other hand, the single part of the polarizing plate 10 which has no electrical contact transmits at least enough light 16 to completely erase the above-mentioned charges, and therefore, the line light on the photoreceptor l is 1° as shown in the figure. The electrostatic latent @SS 54 (indicated by a positive charge) remains only in the tip portion, and the electrostatic latent image is erased in the portion on the sensory body through which the light 16 is transmitted.

Next, a ninth example of the operation of the polarizing plate to obtain the required image area as shown in FIG. 10 will be explained.

Among the three-ply polarizing plates as shown in FIG. 11, the polarizing plate 101
If 10j and 10j are considered as one set, it is possible to operate in the same manner as the operation example of the two-ply polarizing plate shown in FIG. 5, FIG. 8, or FIG. 9. That is, the amount of polarizing plate is 10/10j
and the polarizing plate 10 are moved up and down at an intermediate time.
Simultaneous movement type similar to the example in the figure, (i+) Alternate movement type similar to the example in Figure 8, which moves alternately, (+10 Either one is fixed on the optical path of the image area control light and the other is It is possible to perform a one-sided moving operation similar to the example shown in FIG. If the entire image is to be left, such as in the area up to the rear end, it is sufficient to block the light 16 with a light-transmitting member such as a frame of a polarizing plate.

Furthermore, if the polarizing plates 101 and 10j in FIG. 11 are made to correspond to the polarizing plates 10e and 10fK in FIG. 5, respectively,
In order to obtain an image as shown in Fig. 4, which leaves a part of the original image, polarizing plates 101 (10.) and 10j (10f
) is operated as shown in FIG. S to obtain an image as shown in FIG. (10.).multidot.10 j (10f) in the same manner as in the example shown in FIG. 5, the above-mentioned intermediate time movement Witc in the three-ply polarizing plate is obtained. In other words, depending on whether or not one is added to the polarizing plates with the same configuration, it is possible to leave a part of the original image or erase the same area, and with a simple combination of polarizing plates, the above It is possible to achieve such a wide range of control over image formation.

In addition, in FIG. 11, the polarization directions of the polarizing plates 101 and 10j are combined, and the entire polarizing plate 10 is the polarizing plate 101.1.
It may be configured so that it is perpendicular to the polarization direction of 0j,
Further, in FIG. 11(2), electrostatic latent images 53 and 54 can be obtained on the photoreceptor 1 even if the polarizing plate 101 is placed close to the polarizing plate 10k as shown in 10j.

Above, an embodiment of an image forming method for obtaining a necessary image area by erasing charges in an unnecessary image area on a photoreceptor has been described in detail. At that time, in each of the examples, an example was shown in which the photoreceptor was irradiated with light for erasing charges on the photoreceptor at the same time as the exposure light of the original image. However, it is not necessarily necessary to irradiate the above light simultaneously with the exposure light. That is, during the electrostatic latent image forming process, the light can be applied to any position on the photoreceptor, either before the exposure position or after the exposure position.

Furthermore, when using a photoreceptor with a three-layer structure as described in Japanese Patent Publication No. 42-23910 by the applicant of this patent,
The photoreceptor may be irradiated with the above light simultaneously with the exposure light of the original image.

Furthermore, the above-mentioned light can be irradiated as so-called whole-surface exposure light for producing latent image contrast after the exposure position on the three-layer photoreceptor.

FIG. 12 is a precedent example showing electrostatic latent image formation when using a five-layer photoreceptor consisting of a conductive layer, a photoconductive layer, and a surface insulating layer. In the figure, a drum-shaped three-layer photoreceptor 54 rotating in the direction of the arrow is first energized by a positive polarity corona discharger 55.
It is charged to ten. Subsequently, when reaching the exposure section 56, the light is subjected to AC charge removal by a KAC-10 discharger 58 simultaneously with the exposure light 57 of the original image. Next, full-face exposure is performed by the first full-face exposure light source 60, and an electrostatic latent image is formed on the surface of the photoreceptor 54.

This embodiment is intended to prevent the formation of an electrostatic latent image in the non-image forming area by controlling the area exposed on the entire surface during the above-mentioned overall exposure.

In the figure, the overlapping position of the polarizing plate 101/Iom is controlled as described above, and
It moves across the optical path of the light 61 like the polarizing plate in the figure. By the light blocking effect of these polarizing plates, the formation of an electrostatic latent image can be controlled in the same way as the method of erasing charges on a photoreceptor. However, the latent image formation results are different between the method of controlling full-surface exposure and the method of erasing the charged charges.

Next, electrostatic latent image formation in the method of controlling full-surface exposure will be explained in detail.

FIG. 13 shows that, according to the principle of the present invention, in which the control light of the image area is controlled by overlapping polarizing plates as described above, an electrostatic latent image is formed in an arbitrary area of the three-layer photoreceptor during full exposure. This figure shows an example of how to form the image.

In the figure, light 61 is blocked by a part of the overlapping polarizing plates 10n*10°, and is transmitted by a single polarizing plate. In the electrostatic latent formation technique on a three-layer photoreceptor, A
If the photoreceptor is not irradiated with light after the simultaneous exposure and C charge removal, no electrostatic contrast will occur and no electrostatic latent image will be formed. Therefore, as shown in the figure, the light-shielded portion KFi on the three-layer photoreceptor 54 is not formed with a latent latent image, and only the nine portions irradiated with the light 61 have a latent latent image @64 and 65 (+ charged charges). ) is formed. Further, an electrostatic latent image 68 is formed in a shape opposite to the latent images 64 and 65 in FIG. 13 only on the portion of the photoreceptor 54 irradiated with the fourteenth light 61. Moreover, this first
3 and FIG. 3 (2), and FIG. 14 and FIG. 11 (2), it is clear that the method for controlling the entire surface exposure (
Figures 13 and 14) and methods for erasing charged charges (Figure 3)
In FIG. 2 and FIG. 11 (powder), the pattern of formation of the electrostatic latent image is completely opposite even though polarizing plates having the same configuration are used. We have shown examples of how to do this depending on whether you want to leave a part of the original image first, erase the exact same area as the slippage, and whether or not to add a polarizing plate. This shows that similar results can be obtained using a combination of methods.

FIG. 15 shows an example of a method for leaving or erasing a selected image area by changing the light irradiation position of the image area on the three-layer photoreceptor.

When trying to obtain an image such as area B in FIG.
The photoreceptor 54 is irradiated with 70 m of 0rK-controlled light at the same time as the exposure light 71 of the original drawing bond, thereby erasing the electrical charges in unnecessary areas on the photoreceptor.

Furthermore, when trying to obtain an image such as the area shown in FIG.
The light distribution is 70bt-! It), photoreceptor 5
What is necessary is to prevent the formation of an electrostatic latent image on 4. This makes it possible to select an image area without changing the configuration of the polarizing plate.

In addition, in FIG. 15, the polarizing plates 10q and 10r of the above example
Instead of the polarizing plate 1G-・10o・in FIG.
A three-ply polarizing plate such as a 10p polarizer may be used, and in this case, the same result as in the above example can be obtained, except that the image formation depending on the irradiation direction of the dimming light is reversed.

As described above, according to the present invention, since the mask means moves in synchronization with the movement of the boundary between the image forming area and the non-image forming area, the boundary between the two areas can be clearly formed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a copying machine used in an embodiment of the present invention. Second
The figure is an explanatory diagram of the control process for the image forming area range, and Fig. 3 (1)
) is an explanatory diagram showing the stacking of polarizing plates. Figure 3 (The powder is
FIG. 4 is an explanatory diagram of latent image formation when the above polarizing plate is used. FIG. 4 is an explanatory diagram of the required image area. FIG. 5(1) to FIG. 5(4) are explanatory views of the movement of the polarizing plate. Figure 6- is a perspective view showing an example of the polarizing plate ss and knit, Figure 7 is an explanatory diagram of the positioning means of the monitor mechanism, Figures 8 (1) to 8 (4) and Figure 9 (
1) to FIG. 9(4) are further explanatory views of the movement of the polarizing plate. The sio diagram is an explanatory diagram of the required image area in the opposite form to that of Figure 4.
FIG. 11 (1) and FIG. 11 (hereinafter referred to as explanatory diagrams showing an example of overlapping three-ply polarizing plates and their latent image formation explanatory diagrams. 1st
FIG. 2 is an explanatory diagram of the control process of the image forming area range when a three-layer photoreceptor is used. Fig. 13 is an explanatory diagram of latent image formation when a two-layer polarizing plate is used during full-surface exposure.*IE Fig. 14 is an explanatory diagram of latent image formation when a three-layer polarizing plate is used during full-surface exposure. Figure 15 shows that when the light irradiation position is changed, 1
FIG. 1 is an explanatory diagram illustrating selection of a region that is likely to be m-shaped. In the figure, l is a photoreceptor, 3 is a document table, 4ti original image,
9 is a light source for controlling the range of the image forming area, 010 with the subscript is a polarizing plate, 42#i screen, 54 is a three-layer photoreceptor, 60 is a light source for controlling the range of the image forming area, 1
6.61 shows the control light in the image forming area range〇Applicant Canon Co., Ltd. Figure 3 Figure 4 [2] Figure/UE Figure 1θ Figure 11

Claims (1)

[Claims] In an electrophotographic apparatus that exposes an image to a moving electrophotographic photoreceptor while moving it, a light source that illuminates the photoreceptor in order to stop the non-image forming area of the photoreceptor from becoming visible, and a photoreceptor. a mask means for blocking light from the light source to an image forming area or a non-image forming area of the body, the mask unit moving in synchronization with the movement of the image forming area and the non-image forming area as the photoreceptor moves; An electrophotographic device comprising: a mask means.