JPH023991B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electrophotographic apparatus that uses the so-called Carlson process for copying an image of a document surface onto plain paper, and more particularly, to an electrophotographic apparatus that copies a document surface image onto plain paper, and more specifically, an electrophotographic apparatus that copies a document surface image onto plain paper. The present invention relates to an electrophotographic apparatus that can be used for copying at a copy density of .

Structure of a conventional example and its problems FIG. 1 is a front view of a main part showing the structure of a conventional electrophotographic apparatus using the Carlson process. When copying an original, the photoreceptor 10 is rotated in the direction of the arrow 12, and first, a uniform charge is applied to the photoreceptor 10 by the charger 14 by corona discharge.
In the meantime, the original 16 is moving to the left, and the original surface 18 of the original 16 is illuminated by a fluorescent lamp 20 serving as an original surface irradiation means, and an imaging optical system such as an optical fiber 22 having a lens effect is used to form an image. A reflected image of the document surface 18 is formed on the photoconductor 10 by the system, and the document 16 moves to the right in synchronization with the rotation of the photoconductor 10, sequentially from the right end to the left end of the document surface 18.
The image is formed on the photoreceptor 10, and an electrostatic latent image is formed on the photoreceptor 10.

In the developing device 24, toner adheres to the electrostatic latent image on the photoreceptor 10 according to the charge distribution state, and a developed image is formed on the photoreceptor 10. The amount of toner attached depends on the magnitude of the bias voltage applied by the bias voltage applicator 26. This developed image is the transfer device 2
8 onto the plain paper 30 and the plain paper 30
A copy image of the original surface 18 is created.

However, in the above configuration,
When copying a document in which the density of the high-density areas where characters or pictures are drawn is almost uniform, and the density of the low-density areas where nothing is drawn is also almost uniform, it is necessary to It is easy to obtain a high-density copy image, but for example, if a newspaper cutout has a high-density background with high-density text or pictures, and another with a thin pencil on a blank sheet of paper. If you want to copy a sheet of manuscript paper that has a low-density background and parts with low-density text or pictures, such as a drawn manuscript, then If the image is copied at a higher copy density, that is, at a lower overall density, there is a risk that characters drawn with a pencil will not appear in the copied image. Furthermore, if the copying density corresponds to the density of the pencil characters, that is, the overall density is high, there is a risk that the printed newspaper image will have a large amount of fog. Conventional electrophotographic apparatuses have had the above-mentioned problems.

OBJECT OF THE INVENTION An object of the present invention is to eliminate such problems with conventional electrophotographic apparatuses, and by inputting arbitrary positional coordinates of a document using a coordinate input means, the developing device is operated according to the positional coordinates. An object of the present invention is to provide an electrophotographic apparatus that can form a copy image with a desired density by controlling a bias voltage.

Structure of the Invention The electrophotographic apparatus of the present invention provides a copying device including a developing device having a coordinate input device capable of reading arbitrary position coordinates of a document and a bias voltage application device applying a bias voltage to control copy density. and,
A bias voltage control means for controlling a bias voltage of a developing device is provided, and a bias voltage corresponding to a specified copy density is applied according to a predetermined area of the document based on the position coordinates input by the coordinate input means. , so that a desired portion can be copied at a desired density.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a perspective view of essential parts showing the structure of an embodiment of the electrophotographic apparatus of the present invention.
In FIG. 2, when copying, the photoreceptor 1
0 is rotating in the direction of an arrow 12, and around this photoreceptor 10, a charger 14 and a document surface 1 of a document 16 are placed.
a fluorescent lamp 20 as a light irradiation means for irradiating light on 8;
Document surface 18 of document 16 illuminated by fluorescent lamp 20
A reflected image of the image is formed on the photoreceptor 10,
an obtacle fiber 22 having a lens effect as an imaging optical system that exposes the image, a developer 24 that attaches toner to the photoreceptor 10 according to the charge distribution on the photoreceptor 10 to form a developed image, and a copy density A bias voltage applicator 26 that applies a bias voltage to control the photoreceptor 10, and a transfer device 28 that transfers the developed image on the photoreceptor 10 onto plain paper are arranged.

In addition to the copying means described above, a tablet 32 as a position coordinate detection member capable of reading arbitrary position coordinates on the document surface 18 of the document 16 and a copy density designation switch 3 as a density input means are provided.
Position coordinate input unit 36 including 4a to 34e
A cursor 38 is provided as a position coordinate input means for inputting position coordinates. tablet 3
2 has the X axis and Y axis with the coordinate origin 40 as the origin.
A shaft is provided. Further, the original table 44 of the original table 42 is provided with an X' axis and a Y' axis with the coordinate origin 46 as the origin.

Next, the procedure and operation for copying will be explained. First, with the original surface 18 of the original 16 facing upward, the two intersecting sides of the original 16 are aligned with the X-axis and Y-axis of the tablet 32, respectively.
One vertex of the document 16 is made to coincide with the coordinate origin 40 of the tablet 32. Original 1 on tablet 32
6 is completed, specify the desired position coordinates using the cursor 38. Details at this time will be explained using FIG. 3.

FIG. 3 is a plan view showing the document 16 placed on the tablet 32. If you want to copy only a certain part of the original surface 18 of the original 16 with a density different from other parts, for example, as shown in FIG.
(X ₁ , Y ₁ ), B (X ₂ , Y ₁ ), C (X ₂ , Y ₂ ), D (X ₁ ,
If you want to copy a rectangular area specified by the four points _Y2 ) with a darker density than other parts, first copy the area A,
The copy density designation switch 34b corresponding to the desired copy density of portions other than B, C, and D is pressed. Next, input four points A, B, C, and D using the cursor 38, and press the copy density designation switch 34d corresponding to the desired copy density of the areas A, B, C, and D. Here, copy density designation switches 34a to 34
e is used to sequentially designate higher densities from the copy density designation switch 34a to the copy density designation switch 34e.

After inputting the position coordinates and copy density is completed, the original 16 is transferred from the tablet 32 to the original mounting table 44 of the original table 42. On the document mounting table 44,
An X' axis and a Y' axis are provided with the coordinate origin 46 as the origin, and when transferring the original 16 to the original placing table 44, with the original surface 18 of the original 16 facing downward, the tablet 32 can move the The sides along the axis are respectively the X' axis and
The coordinate origin 40 of the tablet 32 is along the Y' axis.
One vertex of the document 16 that has been matched with the coordinate origin 46 of the document mounting table 44 is made to match.

By performing such an operation, as shown in FIG.
Areas A, B, C, and D on the original surface 18 of the original 16 are copied at the same positions as the original surface 18 of the original 16 even on plain paper after copying, and the image positions on the original surface 18 of the original 16 and the plain paper are Consistency with the position of the copied image is maintained.

When the copy start switch 48 is pressed after the original 16 has been placed on the original placing table 44, the original is transferred onto the photoreceptor 10 by the developing device 24 through the charging and exposure process in the same way as in conventional electrophotographic devices. A visible image is formed.

However, the electrophotographic apparatus of the present invention operates differently from conventional electrophotographic apparatuses at the time of forming this developed image. The details will be explained using FIGS. 3 and 4. FIG. 4 is a block diagram showing the signal flow of the electrophotographic apparatus of the present invention.

As explained above, first, the copy density signal inputted from the copy density designation switch 34b corresponding to the desired copy density of areas other than areas A, B, C, and D in FIG. 3 is input to the position coordinate input unit 36. A built-in memory 50 as a copy storage member stores the information. Next, position coordinates A (X ₁ , Y ₁ ), B (X ₂ ,
Y ₁ ), C (X ₂ , Y ₂ ), D (X ₁ , Y ₂ ), and a copy density designation switch corresponding to the desired copy density of areas A, B, C, and D surrounded by these four points. A memory 50 stores the copy density signal input from the copy density signal 34d, and a copy processing circuit 52 built in the position coordinate input unit 36 calls out the two copy density signals and position coordinates stored in the memory 50. The copy processing circuit 52 includes a bias voltage control circuit 54 that controls the bias voltage to be applied in accordance with the copy density signal, and a timing control circuit 54 that controls the application timing and application time of the bias voltage to be applied in accordance with the position coordinates. A control circuit 56 is provided.

As shown in FIG. 3, when it is desired to copy areas A, B, C, and D with a higher density than other areas, the magnitude of the bias voltage of the developing device 24 is first inputted from the copy density designation switch 34b. The bias voltage control circuit 54 calculates the copied signal, and the bias voltage applicator 26 controls the developing unit 2 according to the calculation result.
It has become the value applied to 4.

Next, when the copy start switch 48 is pressed,
The timing control circuit 56 is activated, and the areas A, B, C, and D in FIG. 3 formed on the photoreceptor 10 are
The time required for the sides B and C of the photoreceptor 10 to rotate in the direction of the arrow 12 and reach the predetermined position, and the time required to change the bias voltage from the sides B and C to the sides A and D. calculate. A bias voltage is applied to the developing unit 24 by the bias voltage applicator 26 in accordance with the result of the calculation and the result of the bias voltage control circuit calculating the copy signal inputted from the copy density designating switch 34d. Due to this applied bias voltage, the area A on the photoreceptor 10,
More toner adheres to the latent image portions corresponding to B, C, and D than other portions, and a visible image is formed.

After the developed images of areas A, B, C, and D are formed, the bias voltage applied by the bias voltage applicator 26 to the developing device 24 is controlled by the copy density designation switch according to the signal output from the timing control circuit 56. 34
It is lowered to the value according to b.

As described above, by changing the bias voltage, more toner adheres to areas A, B, C, and D than to other areas.

Thereafter, by the transfer device 28 in FIG.
The developed image on the photoreceptor 10 is transferred to plain paper, and a copied image is completed in which only areas A, B, C, and D are darker than other areas.

Next, other embodiments of the present invention will be described with reference to the drawings.

FIG. 5 is a plan view showing a state in which a document 16 is placed on a tablet 32 in another embodiment of the present invention. The document surface 18 of the document 16 is divided into three areas as shown in FIG. A case in which it is desired to copy areas of the image with different densities will be described with reference to FIGS. 2, 4, and 5.

First, the copy density designation switch 34b corresponding to the desired copy density of areas G, H, I, and J is pressed. The copy density signal from the copy density designation switch 34b is stored in the memory 50.

Next, input four points F, G, J, and K using the cursor 38, and press the copy density designation switch 34e corresponding to the desired copy density of the areas F, G, J, and K. After that, use the cursor 38 to select 4 of E, F, K, and L.
A point is input, and the copy density designation switch 34a corresponding to the desired copy density of areas E, F, K, and L is pressed. Through the above operations, the position coordinates and copy density signals of each area are stored in the memory 50.

After inputting the position coordinates and copy density is completed, the original 16 is transferred from the tablet 32 to the original mounting table 44 of the original table 42, and the copy start switch 48 is pressed.

When the copy start switch 48 is pressed, the photoreceptor 1 is transferred to the photoreceptor 1 by the developing device 24 through charging and exposure processes.
A visible image is formed on 0. At this time, memory 5
The copy processing circuit 52 calls out the position coordinates and copy density signal stored in 0, and the bias voltage applicator 26 operates the developing unit 2 according to the calculation result of the copy processing circuit 52.
Apply a bias voltage to 4. As a result, areas E, F, K, L, areas F, G, J, K, areas G,
The amount of toner adhesion is controlled in accordance with the copying density of each of the H, I, and J areas.

Thereafter, the developed image on the photoreceptor 10 is transferred onto plain paper by the transfer device 28, and each area becomes a copy image with a different density.

As described above, according to this embodiment, there is provided a cursor capable of inputting arbitrary positional coordinates of a document, a tablet capable of detecting arbitrary positional coordinates of the document inputted by the cursor, and a To add to a conventional electrophotographic apparatus a copy density designation switch that can specify copy density, a memory that stores position coordinates and copy density, and a copy processing circuit that can perform copy processing according to position coordinates and copy density. This achieves the effect that only a desired portion of the same document can be made into a dark copy image or a light copy image.

Furthermore, since the positional coordinate input unit is removable from the copying means, the positional coordinates and copy density of the original to be copied can be entered at any position, regardless of the position of the copying means. This effect can also be obtained. Of course, it is also possible to use the position coordinate input unit by attaching it to the copying means.

Effects of the Invention As is clear from the invention described above, the present invention provides a coordinate input means that can read arbitrary position coordinates of a document, a bias voltage control means that can control the application of bias voltage, and a Carlson process. Since the copying means is constructed using a copying means using a copying method, an excellent effect can be obtained in that an arbitrary position of a document can be copied with a desired copy density. As a result, even if the same document is divided into multiple parts with different densities, a copy image with the desired density can be easily obtained by inputting the position coordinates and copy density corresponding to each part. can get.

[Brief explanation of drawings]

FIG. 1 is a front view of main parts showing the configuration of a conventional electrophotographic apparatus, FIG. 2 is a perspective view of main parts showing the structure of an electrophotographic apparatus according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a block diagram showing the signal flow of the electrophotographic apparatus of the present invention; FIG.
The figure is a plan view showing the positional coordinates of the document surface and the area specified by the positional coordinates in another embodiment of the present invention. 10...Photoconductor, 12...Arrow indicating the rotation direction of the photoconductor during copying, 14...Charger, 16...Original, 18...Document surface, 20...Fluorescent lamp, 22...
Optical fiber, 24...Developer, 26
...Bias voltage applicator, 28...Transfer device, 30
... Plain paper, 32 ... Tablet, 34a-34
e...Copy density designation switch, 36...Position coordinate input unit, 38...Cursor, 40...Coordinate origin of tablet, 42...Original table, 44...Document placement table, 46...Coordinates of document placement table Origin, 48
...Copy start switch, 50...Memory, 52
... copy processing circuit, 54 ... bias voltage control circuit, 56 ... timing control circuit.

Claims (1)

[Scope of Claims] 1. Copying means including a developing device having coordinate input means capable of reading arbitrary positional coordinates of a document, and bias voltage applying means for applying a bias voltage for controlling copy density; The apparatus further comprises a bias voltage control means for controlling the bias voltage of the device, and the bias voltage is changed according to a predetermined area of the document based on the position coordinates input by the coordinate input means. Electrophotographic equipment. 2. The bias voltage control means is characterized by comprising a density input means for inputting a desired copy density signal, and a bias voltage control circuit capable of changing the bias voltage to be applied in accordance with the copy density signal. An electrophotographic apparatus according to claim 1. 3. A patent claim characterized in that at least the concentration input means of the coordinate input means and the bias voltage control means are integrated, and the coordinate input means and at least the concentration input means of the bias voltage control means are made detachable from the copying means. The electrophotographic apparatus according to item 1 or 2. 4. The coordinate input means includes a position coordinate specifying member for specifying position coordinates, a position coordinate detecting member for detecting the position coordinates specified by the position coordinate specifying member,
a copy storage member that stores the position coordinates detected by the position coordinate detection member and a copy density signal inputted by the density input means; and a copy storage member that reads the position coordinates and the copy density signal from the copy storage member to make a desired copy. 3. An electrophotographic apparatus according to claim 1, further comprising a copy processing circuit that outputs a corresponding copy signal.