JPH05162379A - Electrophotographic recording device - Google Patents

Abstract

PURPOSE:To prevent the life of a photosensitive drum or an exposure head from becoming short when a chart containing a contour line which specifies an area to be drawn is depicted. CONSTITUTION:CAD data(plotter command) containing a contour and a figure is stored in an input buffer, and internal(intermediate) data obtained by an analysis part 2 has only a contour line extracted 17 a contour data extraction part 3. The contour line thus extracted is shifted in the linear direction of an LED head, based on the output value of a counter 11, by a contour data shift part 4. In addition, chart data developed into bit map data by a bit map development processing part 5 is stored in a frame buffer 6. The chart data is read sequentially by a controller 7 and then is supplied set by set to a shift register 9. The controller 7 allows a counter 11 to increment, if a single sheet of chart is completed, and thereby, allows contour data to shift in the linear direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording device such as an LED plotter, a liquid crystal printer and a laser printer.

[0002]

2. Description of the Related Art Conventionally, in the field of automatic drafting machines, along with pen plotters, electrophotographic recording devices such as LED plotters, liquid crystal printers, laser printers, etc., because of their high speed of drawing, low noise and easy maintenance Is used. As is well known, in this type of electrophotographic apparatus, a toner image is obtained by uniformly charging the photosensitive drum, forming an electrostatic latent image by a photosensitive process, and then developing the electrostatic latent image. Is recorded on the recording paper by transferring and fixing.

By the way, generally, in order to specify the drawing area in the drawing, a contour line is drawn on the peripheral portion by a thick solid line (0.5 mm or more). A title block is provided at the lower right of this outline. The contour line may be transmitted from the CAD system to the electrophotographic recording device together with the graphic data, or may be set inside the electrophotographic recording device according to the size of the recording paper.

[0004]

The contour line is the longest straight line in the drawing. In particular, the recording position of such an outline is uniquely determined according to the paper size. Therefore, in the electrophotographic recording apparatus, a local portion where the contour line of the photosensitive drum is recorded is exposed with an extremely high frequency as compared with other locations. For this reason, the photoreceptor is likely to deteriorate at such a local portion. Further, in particular, in an electrophotographic recording apparatus using an LED head or a liquid crystal shutter as an exposure means, when a long straight line such as a contour line is drawn in the sheet conveyance direction, a specific LED element or liquid crystal element is continuously driven, Since the operating conditions are more severe than other devices,
The life of the entire head is determined by the life of the element that draws the contour line.

As described above, in the electrophotographic recording apparatus for outputting the drawing data, there is a peculiar circumstance in which a specific portion of the photosensitive drum or the exposure head is overused to draw a contour line.
For this reason, there is a problem in that the life of the entire recording apparatus is shortened due to deterioration of a local portion of the photoconductor or a specific exposure element, although the number of printed sheets is small as a whole.

The present invention has been made in view of the above problems, and even when a drawing including a contour line is drawn, it is possible to effectively prevent the life of the photosensitive drum and the exposure unit from being extremely shortened. It is an object to provide an electrophotographic recording device.

[0007]

An electrophotographic recording apparatus according to the present invention analyzes a drawing data including a contour line that specifies a drawing area of a drawing and a graphic drawn in the contour line, and develops a bitmap. Image processing means, frame storage means for storing the drawing data expanded into bitmap data by the image processing means, and control means for sequentially reading out the drawing data stored in the frame storage means and controlling each part. The recording paper is conveyed under the control of the control means, and an electrostatic latent image is formed on the photosensitive drum based on the drawing data sequentially read from the frame storage means, and the development, transfer and fixing processes are performed. In the electrophotographic recording apparatus including the electrophotographic processing means for recording the contour line and the graphic on the recording sheet, the electrophotographic processing means is N is characterized by comprising a contour shift means for shifting only the position of the contour lines in the drawing data in the photosensitive drum for each outputting an integer of 1 or more) sheets of drawings.

The contour line in the drawing data may be supplied from an external CAD system or the like together with the figure,
It may be set in accordance with the paper size inside the electrophotographic recording device. In the former case, it is necessary to further include contour data extraction means for extracting only the contour line from the drawing data. Further, the contour shift means may shift the storage position of the contour line in the frame storage means, for example, when a bitmap is developed.

[0009]

[Function] According to JIS (machine drawing), the left and right margins of the outline of the drawing are 20 mm or more in the large drawing (A0, A1),
In the small and medium-sized drawings (A2 to A3), the width is specified to be 10 mm or more, and 25 mm or more when the left side is used as the binding margin, but in practice, a width of about ± 2 mm is allowed. According to the present invention, the position of the drawing data on the photosensitive drum is shifted each time N sheets are printed, for example, within this width range. Therefore, every time N sheets are printed, the position of drawing the contour line on the photosensitive drum and the position of the element of the exposure head to be used also shift.

As described above, according to the present invention, the position where the contour line is drawn on the photosensitive drum and the element of the exposure head which is required to draw the contour line can be changed every N sheets of the drawing, so that it is possible to change it compared with the conventional case. The use time of the position corresponding to the outline of the photosensitive drum or the exposure head can be shortened to several tenths to several tenths.
Therefore, the life of the photosensitive drum and the exposure head can be significantly extended as compared with the conventional case. Further, according to the present invention, since only the contour line is shifted, the amount of data used for the shift processing is small, and the shift processing does not spend much time.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a functional block diagram showing the configuration of the LED plotter according to the first embodiment of the present invention. Drawing data including contour lines and figures are, for example, ASCII.
It is transmitted from a CAD system (not shown) in the form of CAD data (plotter command) including a coat. This CAD data (plotter command) is stored in the input buffer 1. The CAD data (plotter command) stored in the input buffer 1 is analyzed by the analysis unit 2 and converted into internal (intermediate) data composed of vector data. Of the internal (intermediate) data obtained by the analysis unit 2, only the contour line is extracted by the contour data extraction unit 3. The contour data shift unit 4 determines the arrangement position of the extracted contour line, and the bitmap expansion processing unit 5 determines the DDA (Digital differenti
al analyzer) is processed and developed into bitmap data. The obtained bitmap data is stored in the frame buffer 6.

The bitmap data stored in the frame buffer 6 is sequentially read by the controller 7. The controller 7 controls an electrophotographic processing unit 8 which will be described later to control the conveyance of recording paper, sequentially supplies the drawing data read from the frame buffer 6 to the shift register 9, and further electrostatic latent images on the photosensitive drum. Control electrophotographic processes such as image formation, development, transfer and fixing. The shift register 9 sends the supplied drawing data to the LED head 10, which is the exposure head of the electrophotographic processing section 8. The LED head 10 is driven by the drawing data.

On the other hand, the controller 7 recognizes from the amount of data transferred to the shift register 9 that the supply of the drawing data for one sheet has been completed, and causes the counter 11 to count up. The output of the counter 11 is supplied to the contour data shift unit 4 as data that specifies a reference point when the bitmap is developed.

FIG. 2 is a schematic diagram showing a schematic configuration of the electrophotographic processing section 8. That is, the photosensitive drum 21 that rotates in the direction of the arrow in the drawing at the time of recording is provided inside the plotter body. Around the photosensitive drum 21, the following elements necessary for the electrophotographic process are arranged.

First, the photosensitive drum 21 is, for example, 800 to 1000 on the most upstream side in the rotation direction of the photosensitive drum 21.
A main charger 22 that uniformly charges V is arranged. At a position downstream of the main charger 22, the photosensitive drum 21 charged by the main charger 22 is selectively exposed according to drawing data to form an electrostatic latent image L.
An LED head 10 composed of an ED (light emitting diode) element array and a SELFOC lens 23 for focusing light from the LED head 10 on a photosensitive drum 21 are arranged. A developing unit 24 that supplies toner to the photosensitive drum 21 to visualize the electrostatic latent image as a toner image is arranged at a position downstream of the LED head 10. A transfer device 25 that supplies electric charges for transferring the toner image formed by the developing device 24 onto a recording sheet is disposed at a position downstream of the developing device 24. At the downstream position of the transfer device 25, a peeling device 26 that supplies electric charges for peeling the recording paper from the photosensitive drum 21 is arranged. Stripper 26
A cleaning device 2 for removing the toner adhering to the photosensitive drum 21 and cleaning the surface of the photosensitive drum 21 at a position further downstream thereof.
7 are arranged. Further, at a position downstream of the cleaning device 27, that is, at a position immediately upstream of the main charger 22, a charge eliminating lamp 28 for removing residual charges on the photosensitive drum 21 is arranged.

Further, the electrophotographic processing section 8 is detachably provided with a paper feed cassette 32 for holding the recording paper 31. The recording paper 31 held in the paper feed cassette 32 is supplied to the paper conveyance path by the paper feed roller 33. The recording paper 31 supplied to the paper conveyance path is supplied to the above-mentioned transfer device 25 and peeling device 26 via the feed roller 34. Further, a fixing device 35 is arranged at a position downstream of the peeling device 26 in the paper conveyance path. A feed roller 36 is arranged downstream of the fixing device 35, and a stacker 37 for holding recorded recording paper is arranged further downstream thereof.

Next, the operation of the LED plotter according to this embodiment having the above structure will be described. FIG. 3 is a flowchart showing the operation of the plotter. When the CAD data (plotter command) is stored in the input buffer 1 and analyzed by the analysis unit 2 and converted into internal (intermediate) data, the flow of FIG. 3 is activated. First, the contour data extraction unit 3 extracts contour data (S1). Whether or not it is a contour line can be determined by, for example, whether or not it is the outermost frame line from the coordinate values at both ends.
Further, all the line segment data connected to the line segment data extracted as the contour lines are also extracted as the contour lines. As a result, it is possible to shift the title block, the center mark, the area display of the drawing, and the like.

Next, in the contour data shift section 4, the counter 1
The position where the contour line is to be arranged is determined with a count value of 1 (this is C1) as a reference point. That is, the offset value based on the count value C1 is added to the X (line direction) coordinate of each vector forming the contour line (S2). At this time, if not only the X coordinate but also the Y coordinate is shifted, the contour line is also shifted in the paper transport direction. Next, the electrophotographic processing unit 8 is activated to execute the print processing for one sheet (S3), and when this processing is completed, the counter 11 is counted up under the control of the controller 7 (S4).
If the counter value C1 exceeds the maximum shift amount CL,
C1 is reset to 0 (S5, S6). The maximum shift amount CL is determined by the allowable width (± 2 mm) of the deviation of the contour line, the arrangement pitch of the LED elements of the LED head 10, the one-time shift pitch, and the like. The above processing is continued until printing is completed (S7).

FIG. 4 is a diagram for explaining the operation of the present LED plotter. In the first drawing, as shown in FIG. 4A, the LED elements P1 and P2 of the LED head 10 are continuously used and the vertical line of the contour line 41 is drawn. In the drawing of the eye, as shown in FIG. 4B, only the contour line 41 is displaced to the left by one pitch Δx of the LED elements, and therefore the LED for drawing the line in the vertical direction of the contour line 41 is drawn. The LED elements of the head 10 are changed to P3 and P4 to prevent continuous use of P1 and P2. It should be noted that the graphic 42 does not have the problem of contour line drawing, and is therefore drawn at the same position.

When the LED elements are arranged at a pitch of 16 dots / mm and the contour line is 0.5 mm, the contour line is 8
It is drawn by the LED elements for the dots. If the shift operation is carried out dot by dot, and if the allowable width is set to 2 mm, the process goes round once for 32 shift operations. In this case, even the LED element used for the longest time is
It will be shortened to 4 energization time.

FIG. 5 shows an LED according to the second embodiment of the present invention.
It is a functional block diagram which shows the structure of a plotter. In FIG. 5, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description of the overlapping parts will be omitted. In this embodiment, the contour data is CAD data (plotter command) from the CAD system.
The present invention is applied to the case where the above is not transferred.

That is, the LED plotter is provided with a paper size input device 51, and this paper size input device 51 is provided.
A contour line is generated by the contour data setting unit 52 according to the input status of, and the contour line is supplied to the contour data shift unit 4. The processing after the shift of the contour data supplied to the contour data shift unit 4 is the same as that in the first embodiment. According to this embodiment, since the contour line is given from the contour data setting unit 52, the operation of extracting only the contour line from the drawing data becomes unnecessary, and the process can be simplified accordingly.

FIG. 6 is a functional block diagram showing the structure of an electrophotographic recording apparatus according to the third embodiment of the present invention. In addition,
6, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description of the overlapping parts will be omitted. In this embodiment, the contour line is shifted every time N (a number that can be set arbitrarily) is printed.

That is, when the controller 7 transfers one sheet of drawing data to the shift register 9, it causes the counter 61 to count up. On the other hand, the operator uses the input device 62
It is possible to arbitrarily set N (integer of 1 or more) via. The comparator 63 compares the set value N set by the input device 62 with the counter value C2 of the counter 61. The coincidence output of the comparator 63 serves as a clock signal for counting up the counter 11. Counter value C of the counter 11
1 is supplied to the contour data shift unit 4.

FIG. 7 is a flow chart showing the operation of this embodiment. The operation of this apparatus is based on the operation shown in FIG. 3, but in this embodiment, printing processing for one sheet (S
When 13) ends, the count value C2 is incremented (S14), and the count value C1 is incremented every time the count value C2 exceeds N (S15, S16). According to this embodiment, since the shift timing can be set arbitrarily, when outputting N different drawings, the contour lines are output at the same position for the N identical drawings. It becomes possible to perform operations such as doing.

In the above embodiments, the LED plotter is taken as an example, but it goes without saying that the present invention can be applied to other electrophotographic recording devices such as liquid crystal printers and laser printers.

[0027]

As described above, according to the present invention, the position of the contour line drawn on the photosensitive drum is changed for every N sheets of drawing, so that the contour line of the photosensitive drum is drawn. It is possible to reduce the use time of the element for drawing the contour line of the exposure head and the exposure head to several tenths to several tenths of the conventional time. As a result, it is possible to prevent overuse of specific parts of the photosensitive drum and the exposure head, and it is possible to significantly improve the life of the photosensitive drum and the exposure head. Further, according to the present invention, since only the contour line is shifted, the amount of data used for the shift processing can be minimized, and the processing time can be shortened.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration of an LED plotter according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of an electrophotographic processing unit in the plotter.

FIG. 3 is a flowchart showing an operation of the plotter.

FIG. 4 is a diagram for explaining a drawing form by the plotter.

FIG. 5 is a functional block diagram showing a configuration of an LED plotter according to a second embodiment of the present invention.

FIG. 6 is a functional block diagram showing a configuration of an LED plotter according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing an operation of the plotter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Input buffer, 2 ... Analysis part, 3 ... Contour data extraction part, 4 ... Contour data shift part, 5 ... Bitmap expansion processing part, 6 ... Frame buffer, 7 ... Controller, 8 ...
Electrophotographic processing unit, 9 ... Shift register, 10 ... LED head, 11, 61 ... Counter, 21 ... Photosensitive drum, 22
… Main charger, 23… Selfoc lens, 24
... developing device, 25 ... transfer device, 26 ... peeling device, 27 ... cleaning device, 28 ... static elimination lamp, 31 ... recording paper, 32 ... paper feeding cassette, 33 ... paper feeding roller, 34, 36 ... feeding roller,
35 ... Fixing device, 37 ... Stacker, 41 ... Contour line, 42 ...
Figure, 51 ... Paper size input device, 52 ... Contour data setting section, 62 ... Input device, 63 ... Comparator.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B41J 29/26 A 8804-2C B43L 13/00 J 7318-2C G03G 15/00 301 21/00 118 G06F 3 / 12 B 8323-5B

Claims (4)

[Claims] 1. An image processing unit for analyzing a drawing data including a contour line for specifying a drawing area of a drawing and a figure drawn in the contour line and developing a bitmap, and bitmap data by the image processing unit. A frame storage means for storing the drawing data developed in the above, a control means for sequentially reading out the drawing data stored in the frame storage means and controlling each part, and a recording sheet conveyed under the control of the control means. At the same time, an electronic device that forms an electrostatic latent image on a photosensitive drum based on the drawing data sequentially read from the frame storage means, and records the contour line and the figure on the recording sheet through a developing, transferring, and fixing process. In an electrophotographic recording apparatus including a photographic processing means, the electrophotographic processing means outputs the N (where N is an integer of 1 or more) sheets of drawings. Electrophotographic recording apparatus characterized by comprising a contour shift means for shifting only the position of the contour lines in the drawing data in an optical drum. 2. The contour line in the drawing data is supplied from the outside together with the figure, and further comprises contour data extracting means for extracting only the contour line from the drawing data. The electrophotographic recording apparatus according to claim 1. 3. A paper size input means for inputting the size of the recording paper, and a contour setting means for setting a contour line in the drawing data based on the size of the recording paper input by the paper size input means. The electrophotographic recording apparatus according to claim 1, further comprising: 4. The contour shift means shifts a storage position of the contour line in the frame storage means.
The electrophotographic recording device according to the item.