JPH03104663A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To decrease the maximum driving current value required for a plurality of solid-state light emitting element arrays by controlling the switching of the solid-state light emitting element arrays for every color during the exposure period of one scanning line. CONSTITUTION:A line counter 15 is initialized by a horizontal synchronizing signal HSYNC which is outputted from a controller. Thereafter, image data DATA1-DATA4 for individual colors are outputted in synchronization with transfer clock signals CLOCKs for images. In a first color LED array head 2a to a fourth color LED array head 2d, the image data DATA1-DATA4 are inputted into line memories housed in the individual LED array heads in synchronization with the transfer clocks signals CLOCKs. Meanwhile, when the transfer clock signals CLOCKs are counted for one line in the counter 15, a latch signal LATCH is outputted. The latch signal LATCH outputs the image data stored in the line memories in the LED array heads 2a-2d to the sides of LED driving and controlling circuits in the LED array heads. A light-emission control circuit 16 outputs strobe signals STB1-STB4 at the specified timing based on said latch signals LATCHs. The LED array heads 2a-2d are made to emit light at the same time for one line.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to l. ．． A color printer constructed using a solid state light emitting element array such as an ED array head. The present invention relates to an image forming apparatus such as a color facsimile system.

(Prior art) Conventionally, most color printers have adopted a thermal transfer method or an inkjet method.
(Light-emitting diode) printers and the like have lagged behind, mainly due to practical difficulties in their image forming methods.

However, recently, color laser copying machines have begun to be offered.

This conventional color laser copying machine has a pair of an optical system that outputs image data and an electrophotographic process system, and can output one page of color image data in yellow (Y), yellow (Y),
Cyan (C). Color printing is achieved by employing a so-called multi-pass method, which exposes and develops the independent colors of magenta (M) and black (B).

This multi-bus method allows for reduction of the page memory for storing color image data and miniaturization of the device, but since the image is formed using the multi-page scan method, the throughput of the printer decreases. ,and,
There is a problem in that the control mechanism and electronic circuit that control the timing of print output are extremely complex.

Furthermore, in conventional two-color laser printers, color printing is achieved using a so-called one-bath method, in which image formation is completed during one electrophotographic process using an optical system for each color and one electrophotographic process system. However, it had the same problem as above.

However, in recent years, the manufacturing cost of LED array heads has been reduced and the variation in LED light beams has been reduced.
Page printers using ED array heads have appeared. This LED array head is more compact than the optical system of a laser beam printer, and has a simpler configuration of the optical system and control circuit, so it is easier to apply to color page printers than the laser beam optical system. And it's very easy. For example, four LEDs arranged on a photosensitive belt.
) A latent image of each color is formed by an array head, and toner of each color is applied onto the photoreceptor belt to develop the latent image.
Color printing can be done in one bath.

(Problems to be Solved by the Invention) However, conventional color page printers using LED array heads have a simple structure. Although it is easy, since multiple LED elements are made to emit light at the same time (usually, each LED array block is made to emit light), the drive current required for one LED array head is large, and the same amount of drive current is required for multiple LED array heads. There was a problem to be solved in that the amount of current consumed when 1 liter of light was emitted would be extremely large, and a power source for the personnel would be required.

In view of the above-mentioned points, an eleventh object of the present invention is to provide an image forming apparatus that can reduce the maximum value required for a plurality of solid-state light emitting element f arrays such as a plurality of LED array heads. .

[Means for Solving the Problems] In order to achieve the above object, one form of the present invention has a solid state light emitting device for one scanning line, a plurality of solid state light emitting devices is defined as one block, and this In an image forming apparatus C that is composed of a plurality of solid-state light-emitting element arrays that can control the light emission of solid-state light-emitting elements on a block-by-block basis, the light emission switching control of the solid-state light-emitting element array is performed for each color during the exposure period of one scanning line. The invention is characterized in that it has a light emission switching control means for controlling the light emission.

Further, in another embodiment of the present invention, a solid-state light emitting device has solid-state light-emitting devices for one scanning line, a plurality of solid-state light-emitting devices are used as one block, and light emission control of the solid-state light-emitting devices can be performed in block units. In an image forming apparatus composed of a plurality of light emitting arrays, a light emission switching control means is provided which performs light emission switching control for each block recorded in an area common to all solid state light emitting element arrays during the next n period of one scanning line. It is characterized by having.

In still another embodiment of the present invention, the solid-state light emitting device has a solid-state light-emitting device for one scanning line, a plurality of solid-state light-emitting devices are used as one block, and the light emission of the solid-state light-emitting device can be controlled on a block-by-block basis. An image forming apparatus including a plurality of element arrays includes a light emission switching control means for emitting light by combining both light emission switching for each solid state light emitting element array and light emission switching for each block during n light periods of one scanning line. It is characterized by

By dividing and emitting light for each solid-state light emitting element array, or by combining the light emission switching for each solid-state light emitting element array and the divided light emitting for each array block, it is possible to The maximum drive current value required for the head can be reduced.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

(Function) In the present invention, the light emission control for a plurality of solid-state light emitting element arrays during the 1-line scanning period is performed by the light emission switching control means. Common to element array C^. Basic configuration FIG. 1 shows the basic configuration of an embodiment of the present invention. In the figure, A has solid-state light-emitting elements for one scanning line, and a plurality of solid-state light-emitting elements is defined as one block, and light emission control of the solid-state light-emitting elements can be performed in units of blocks. There is a light emitting element array. Reference numeral B designates a light emission switching control means for controlling light emission switching of each solid state light emitting element array A for each color during the exposure period of one scanning line. Light emission switching control 1000 steps B
Alternatively, during the exposure period of one scanning line, light emission switching control may be performed for each block recorded in an area common to all the solid-state light emitting element arrays. Further, the thousand stages B may emit light by combining both the light emission switching for each solid-state light emitting element array and the light emission switching for each block during the exposure period of one scanning line.

l1. First Embodiment\S2 Figure shows the internal configuration of a multicolor LED printer according to an embodiment of the present invention.

In the figure, 1a. 1b, lc and ld set the surface of the photoreceptor belt 4 to a predetermined potential -? l! :Electrify 1
The secondary chargers 2a, 2b, 2c and 2d are respectively a first color (A, for example, yellow), a second color (B, for example, magenta), a third color (C, for example, cyan), and a fourth color (D. , for example, black) onto the photoreceptor belt 4, LED array heads 3a, 3b;
, 3c and 3d are the first color, 7rS2 color,
This is a developing device that stores developer 1 and toner for the third and fourth colors, and uses these toners to develop the latent image on the photoreceptor 4-11 in color. 5 is a transfer device that transfers the toner of each color developed on the photoreceptor belt 4 onto the transfer paper; 6;
7 is a cleaner that wipes off residual toner remaining on the photoreceptor belt 4 after the toner is transferred, and 7 is a cleaner that ensures uniform toner development when the next page of image data is exposed on the photoreceptor belt 4. This is a pre-exposure device that makes the potential on the surface of the photoreceptor belt 4 uniform. 8 is transferred onto the transfer paper by the transfer device 5. A fixing device fixes the copied toner by heat and pressure bonding, 9 is a paper cassette, IO is a paper feed roller that takes out paper from the paper cassette 9, l1 is a paper transport roller, l2
1 is a paper feeding bus, 13 is a paper transport bell 1-, and 14 is a paper tray.

In such an arrangement, image data of each color output from the controller (not shown) is connected to each LED.
It is output at a timing corresponding to the distance between the array heads 28 to 2d, and when first color image data is exposed onto the photoreceptor belt 1-4 by the LED array head 2a, a latent image is formed on the photoreceptor belt 4. Then, the latent images on the photoreceptor bells 1 and 4 are developed with the first color toner by the developing device 3a. Similarly, image data of the second to fourth colors are exposed to latent images on the photoreceptor 1 and developed with corresponding toners.

A sheet of paper is taken out from the paper cassettes 1 and 9 by the paper feed roller 10, which rotates in response to a print start signal from the controller. After a predetermined period of I14, the toner is conveyed at a constant speed toward the transfer device 5, and is transferred by the roller 5 onto the developed I/3-1 sheet-L on the photoreceptor belt 4. Thereafter, the paper is conveyed to the fixing device 8 by the paper conveyance belt 13, and the toner is fixed on the paper by applying pressure at a predetermined temperature by the fixing device 8, and is discharged onto the paper tray 14 as an IJ (IJ) after printing is completed.

The third row shows the main circuit configuration of the first embodiment of the present invention.

In the figure, line counter l5 is initialized by horizontal synchronization {2 -X; IIsYNc output from controller 1/roller side, and then image transfer clock 3''-
5- Image data of each color D^D A in synchronization with CLOCH
When I~D^1A4 is output, each LED array head 28~2d transfers the image data DATAI~DATA4 to each L in synchronization with the transfer clock signal (:LOCK).
The data is manually input to the line memory (not shown) built into the ED array head.

On the other hand, the line counter 15 is the transfer clock f38CLOC.
When K is counted for one line, LED array head 2
A latch signal L A T for outputting the image data stored in the line memory in 8 to 2 d to the LED drive control {[11 path (tt shown in the figure) side] in the LED array head.
Exit C I+. This latch signal - bow LATC1
], the light emission control circuit 16 outputs the probe signal −qS.
Tn+ to ST[l4 are output at predetermined timing, and each [. ED array head 20~2d! Lights up the lines at the same time.

FIG. 4 shows the timing of the image data [lATA1 to [)AT^4 which are inputted from the controller side in FIG. 3. As shown in FIG. 4, the first color image data [lATAl is output after a predetermined time T1 from the leading edge of the rising edge of the vertical synchronizing signal VSYNC output from the printer side. Similarly, the timing at which the second, third, and fourth color "1" image data DATA2, DATA3, and DA4 is output is also set for a predetermined period of time T2, T3, and D4 from the leading edge of the rising edge of the VSYNC signal. Later.

Figure 5 shows the timing of each signal shown in Figure 3.6 In Figure 5, horizontal synchronization from the controller side
After the word II S Y N C is output, one line of image data is transferred for each color, ie, DATAI to DATAI, in synchronization with the image transfer clock CLOCK.
ATA4 is output, and the line counter 15 selects 1.
When the latch signal LATCH is output after counting the line transfer clock signal (:LOCK), the light emission control circuit 16 outputs 1.
It outputs strobe signals ΣSTB1 to STB4 for emitting light for a certain period of time T, . Note that the strobe signals STIII to STB4 are divided into equal intervals TL so as to end before the latch signal LATCH of the next line is output.

The light emission control circuit 16 of this embodiment controls the light emission of one of the plurality of LED array heads 2a to 2d using one strobe.

C. Second embodiment FIG. 6 shows the circuit configuration of the 7JS2 embodiment of the present invention.

The light emission control circuit 17 of the tree embodiment causes the respective common blocks of the LED array heads 2a to 2d, which are composed of N 1 and ED blocks, to emit light at once during one line scanning bright interval. Performs light emission control.

Strobe signal ST[l that causes each LED block to emit light
1 to STBN are output from the light emission control circuit l7 after the latch signal L ATC11 from the line counter l5. However, N is a positive integer of 2 or more.

FIG. 7 shows the timing of each signal in the circuit of FIG.

D. Third Embodiment FIG. 8 shows a circuit configuration of a third embodiment of the present invention. In this embodiment, the light emitting strobe signal STB for each LED block is applied to each of the ED array heads 28 to 2d.
Light emission switching circuits 18a, 18b, which generate I-STBN.
+8c and 18d. The latch signal LATCH from the line counter 15 causes the light emission switching circuit 18a to output the strobe signal STBI - STB2.
→・・・-+STBN is output and ED array head 2
Make a emit light. Thereafter, the light emission switching circuit 18a outputs a light emission start signal 51 to the next stage light emission switching circuit 18b, and the light emission switching circuit 18b causes the ED array head 2b to emit light in the same manner as described above.

The LED array heads 2C and 2d also emit light in the same operating order as above.

FIG. 9 is a timing diagram showing the above operation in the circuit of FIG. 8.

E. Fourth Embodiment FIG. 10 shows a circuit configuration of a fourth embodiment of the present invention. In this embodiment, l. Light emitting strobe for each ED block ST
a light emission switching circuit 20a that generates l'll-STIIN;
20b. 20c and 20d. Also, in synchronization with the latch signal LATCI1 from the line counter l5, the select signal SELI is sent from the timer selector 19.
- SEL4 is output, and each of the light emission switching circuits 2Qa to 20d is independently driven by this select 1 signal.

In this case, each select] ~ signal SELI ~ I of SEL4
B timing can be set so that one LED array head can also emit light while the other ED array head is emitting light. That is, two or more light emission switching circuits 20a to 20d operate at the same time, making it possible to emit the strobe signal.

F. i5 Embodiment FIG. 11 shows the circuit configuration of a fifth embodiment of the present invention. The light emission control circuit 2l of this embodiment generates light emission strobe signals STBI-STBN for each LED block of the L}i D array heads 28 to 2d, and also controls the gates 22a, 22b . The output signals Gl, G2, G3 and G4 control the opening and closing of 22c and 22d. Then, the light emission of each LED array head 28-2d is controlled by the light emission strobe signals STIII-STUN via the gates 22a-22d. Further, this light emission control circuit 2l is initialized by the latch ``;3tATco'' output from the line counter l5,
After that, the light emitting strobe signal 'j'isru + information STFI
1.1 of N and gate control signals 61 to G4 are applied. In this case, there is an advantage that the output order of the light emission strobe signals STBI to STBN and the gate output signals 61 to 64 is not limited.

(Effects of the Invention) As explained above, according to the present invention, the color 1 having a plurality of solid-state light emitting element arrays (LED array heads)
, In an image forming apparatus such as an ED printer, the light emission of each solid-state light emitting element array is
Alternatively, a common sliding array in each solid-state light emitting element array may be used.
Since the light emission for each block or each array head is performed in combination with the separate light emission for each array block, it is possible to reduce the power consumption required during one line scanning as much as possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of an embodiment of the present invention. FIG. 2 is a sectional view showing the internal structure of a multicolor LED printer according to an embodiment of the present invention. FIG. 3 is a circuit diagram of a first embodiment of the present invention. A block diagram showing the configuration; FIG. 4 is a timing diagram showing the output timing of the image data signal Σ of the circuit in FIG. 3; FIG. 5 is a timing diagram showing the output timing of each signal 3 of the circuit in FIG. 3; 6 is a block diagram showing the circuit configuration of the second embodiment of the present invention, FIG. 7 is a timing diagram showing the output timing of each signal 9 in the circuit of FIG. 6, and FIG. 8 is a block diagram showing the circuit configuration of the second embodiment of the present invention. The ninth factor is a timing diagram showing the output timing of each signal i to J in FIG. 8, and FIG. Block diagram showing the circuit configuration, Part I! FIG. 3 is a block diagram showing a circuit configuration of a fifth embodiment of the invention; FIG. Ia~ld-1st order'! jF Electric, 2a~2d...! ．． ED array head, 3a-3d
... Development gain, 4... Photoreceptor bell], l5... Line counter, I6, 17.21... Light emission control circuit, 18a to 18
d, 20a to 20d-light emission switching circuit, 1g... timer selector, 22a 22d-game 1-. Figure 10 Figure I1

Claims (1)

[Scope of Claims] 1) A solid-state light-emitting element array having solid-state light-emitting elements for one scanning line, where a plurality of the solid-state light-emitting elements constitute one block, and the light emission of the solid-state light-emitting elements can be controlled in units of blocks. What is claimed is: 1. An image forming apparatus comprising a plurality of light emitting devices, comprising: a light emission switching control means for controlling light emission switching of the solid state light emitting element array for each color during an exposure period of one scanning line. 2) A solid-state light-emitting element array is composed of a plurality of solid-state light-emitting elements having solid-state light-emitting elements for one scanning line, a plurality of the solid-state light-emitting elements being one block, and capable of controlling light emission of the solid-state light-emitting elements in units of blocks. An image forming apparatus comprising: a light emission switching control means for controlling light emission switching for each block recorded in a common area of all the solid-state light emitting element arrays during the exposure period of one scanning line. Device. 3) A solid-state light-emitting element array is composed of a plurality of solid-state light-emitting elements having solid-state light-emitting elements for one scanning line, a plurality of solid-state light-emitting elements being one block, and capable of controlling light emission of the solid-state light-emitting elements in units of blocks. An image forming apparatus comprising: a light emission switching control means for emitting light by combining both the light emission switching for each solid-state light emitting element array and the light emission switching for each block during the exposure period of one scanning line. Device.