JPS6216663A - Optical write head - Google Patents

Abstract

PURPOSE:To select and change optionally the number of serial input terminals for connecting a lead wire so as to match the kind of a machine for using an optional write head by connecting in series a suitable number of shift registers of a driving circuit of a light emitting element. CONSTITUTION:A driving circuit is constituted of a shift register 23 for storing a prescribed number of picture signals 9, a latching circuit 24 for receiving in parallel and latching the signal which has been stored in this shift register, and gate circuit 26 for supplying a driving pulse 27 to a light emitting element 22. The driving circuit 22 which has been constituted in this way is arranged on a substrate 21, and the respective serial input terminals 231 are connected electrically to a terminal 32 which has been provided on the right end of the substrate 21, through an input signal line 31. To the terminal 32, a flat cable which has bound many lead wires as one body, etc. are soldered directly, or connected through a connector.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention is a method of selectively emitting light from a large number of light emitting elements arranged in two rows on a substrate, etc., and irradiating the light onto the surface of a photoreceptor. The present invention relates to an optical writing head that optically writes image information.

``Prior Art'' There is a device as shown in FIG. 7, for example, which reproduces an image on a document based on an image signal obtained by reading the image on a document using an image line sensor or the like.

This is similar to what is used in so-called xerography set copiers, laser printers, etc.
This shows the main parts of a printer using the method. On the side of this photosensitive drum, a large number of light emitting elements 2 are mounted on a substrate 2.
Optical writing heads 2 with squares arranged in a row are placed facing each other.

In this optical writing head 2, for example, approximately 3000 light emitting elements 2□ are arranged in a line in the axial direction of the photosensitive drum 1. When these light emitting elements 2° selectively emit light in accordance with image signals and the photosensitive drum 1 rotates in the direction of arrow 3, an electrostatic latent image is formed on its outer peripheral surface. After the image is developed by the developer 4, it is transferred onto the recording paper 5. Such a device is described, for example, in Japanese Patent Laid-Open No. 59-184681.

An image signal is sent to this optical writing head by a circuit as shown in FIG.

In the figure, the signal processing circuit 6 transfers the image signal 61.6° for the line to be written (divided into two as described later) to two line buffers 7 at a predetermined timing.
This is a circuit that transfers data to 0.7□. This line buffer 7, . 12 contains the - line image signal 6. ．． 6. is equally divided in the longitudinal direction, and the divided segment signal 91
1 to 91hs 921 to 92n are stored in partitioned buffers 8, 1 to 81. ,．． 821-8□ I am connected.

On the other hand, light emitting elements 2° are arranged linearly on the substrate 21, and drive circuits 1211-12. ,,． 122. ~122o. For each drive circuit, one section buffer 8, 1 to 8. . , 821-8° are connected.

FIG. 9 is a detailed wiring diagram of this drive circuit, for example 1211. Since the arrangement spacing of the light emitting elements 22 is narrow, the lead wires 13 are drawn out alternately upward and downward, and are alternately connected to the drive circuits 14 about 1 m above and below, respectively. That is, for example, one unit of drive circuit 14 that can process a 32-bit image signal is connected here to the -L and bottom of the light emitting elements 2 □, 8 each, and a total of 512 light emitting elements 22 are selected. The structure is such that it emits light.

However, since each unit of drive circuit 14 is arranged separately above and below the light emitting element 22,
The upper 8 pieces are connected in series, the lower 8 pieces are connected in series,
Image signals are supplied from separate serial input terminals 151 and 152, respectively. The image signals input here are the divided image signals 9.1 and 921 in FIG. Therefore,
Each image signal is adjusted to control the light emission of every other light emitting element 2°. This adjustment is performed by the signal processing circuit shown in FIG. 8 and stored in line buffers 71 and 7□, respectively.

In this way, in the circuit of FIG.
22-82. , a predetermined image signal is distributed to each drive circuit 1211-12 . ．． ．． ．． 122,~
12. ．． ．． The storage of image signals for -lines is completed. Thereafter, when a command to output a drive pulse is issued to all drive circuits through a control line (not shown), the light emitting elements 2□ selectively emit light all at once.

"Problems to be Solved by the Invention" In such an optical writing head, an appropriate image signal transfer speed is selected in consideration of the rotational speed of the photosensitive drum 1 shown in FIG. .

However, even if optical writing heads of the same size are used, the rotational speed of the photosensitive drum may differ depending on the model.

Even in such cases, signal processing circuits, buffer connections, and optical writing heads are often shared among the models. This is aimed at reducing costs by standardizing parts, but it is particularly significant in avoiding the complexity of individually designing and manufacturing optical writing heads for each model.

However, it is preferable to simplify the signal processing circuit and the like if there is sufficient transfer speed, and it is preferable that the number of lead wires connected to the optical writing head be as small as possible. For example, in an optical writing head in which about 7,000 light emitting elements are stacked in layers, the number of lead wires is several tens of meters long, and reducing this number is extremely advantageous for improving reliability and manufacturing workability. .

The present invention has been made with attention to the above points, and an object of the present invention is to provide an optical recording head that can arbitrarily select and change the number of serial input terminals to which lead wires for inputting signals are connected. The purpose is to

"Means for Solving the Problems" The optical writing head of the present invention includes a large number of light emitting elements arranged in rows on a substrate, and each of these light emitting elements is divided into a predetermined number of sections. Each section has a drive circuit that selectively supplies drive pulses to all the light emitting elements that make up the section, and this drive circuit is serially input with image signals corresponding to the number of light emitting elements to be driven. A device characterized by being provided with a shift register that receives the image signal from the terminal, a driver that supplies a driving pulse to the light emitting element according to the image signal, and a serial output terminal that outputs the image signal input to the shift register. It is.

Here, it is preferable that pins for attaching a bridge connector for electrically connecting the drive circuits are implanted in one serial output terminal and the other serial output terminal of the mutually adjacent drive circuits.

Further, it is preferable that the same number of adjacent drive circuits are connected in series to each other via their serial input terminals and serial output terminals, and the image signal is supplied from the open serial input terminals.

"Function" As described above, in the present invention, a large number of drive circuits each driving a predetermined number of light emitting elements to emit light are provided on the substrate 2, and the soft register of each drive circuit is provided with a serial input terminal and a serial output terminal.

Then, if necessary, an appropriate number of shift registers of adjacent drive circuits are connected in series. In order to facilitate this connection work, each terminal is provided with a pin for electrical connection, and the two are connected by, for example, attaching a bridge connector.

In this way, the wiring connections are changed so that the number of lead wires is as small as possible, depending on the model that uses the optical writing head. The above configuration makes it extremely easy to change the wiring, and since the production of the optical writing head itself satisfies the requirement for common parts, it is possible to simplify the circuitry of devices that use it. This greatly contributes to improving reliability.

Embodiment FIG. 1 shows a plan view of an optical writing head of the present invention, and FIG. 2 shows a side view of the main parts thereof.

This board 2. On the top, light emitting elements 22 are arranged in a row at the center. In the vertical direction, n drive circuits 22 are arranged vertically symmetrically.

FIG. 3 shows an internal block diagram of this drive circuit 22. As shown in FIG.

This is a shift register 2 that stores a predetermined number of image signals 9.
3, a latch circuit 24 that receives and latches the signals stored in this shift register in parallel, and a light emitting element 2.
2 and a gate circuit 25 that supplies a drive pulse 27 to the drive pulse 27. This gate circuit 25 incorporates the same number of driver Nant gates 25□ as the number of image signals 9. This driver gate 251 receives an image signal from the latch circuit 24 from one end, and supplies the light emitting element 22 from a power source (not shown) by an enable signal 26 inputted to the other end.
It operates to supply a drive pulse 27 to. The anode of each light emitting element 2□ is connected to this driver
25+ output terminals are connected one by one, and the cathodes of all the light emitting elements 22 are connected to one ground line 28. For example, when the image signal "1" is input to one terminal of the driver Nant gate 251 at the far left in this figure, and the enable signal 26 becomes high level, the light emitting element 22
The drive pulse 27 flows toward the ground line 28 through the ground line 28 . This causes the light emitting element 22 to emit light for a certain period of time. When the image signal is O'', the driver gate 25 is not turned on, so no driving pulse flows. For example, when a 32-bit shift register 23 is used, 32 ``0'' or ``1'' image signals are serially input from the serial input terminal 23 of the shift register 23 in synchronization with the clock signal 18.

Since this is supplied in parallel to the driver gate 25 through the latch circuit 24, the 32 light emitting elements 2
2 is selectively emitted.

Such drive circuits 22 are arranged on the board 2 □ as shown in FIG. It is connected. The signal input line 31 is formed of a conductive film provided on the back surface of the substrate 21, that is, a printed circuit. A flat cable or the like having a large number of lead wires bound together is directly soldered to the terminal 32 or connected via a connector.

FIG. 3 is a side view of the main parts, and the serial input terminal 23 and serial output terminal 23o of each drive circuit 22 are connected to the board 2. It is electrically connected by soldering or the like to a printed circuit 34 formed on the back surface of the . Then, each substrate 2. This printed circuit 34 is attached to the pin 35 implanted in the
Electrical connection is made through.

A bridge connector 36 as shown in FIG. 4 is fitted into this pin 35. This is a plastic frame 361 with a copper plate 3 bent into a C-shape.
62 or the like, and when this is inserted into the two pins 35 arranged side by side, the pins are electrically connected to each other.

The optical writing head as described above is used as shown in FIG. 4 or 5.

That is, the segmented image signals 91, to 9, explained in FIG.

, 921 to 92h each correspond to the signal amount stored in two drive circuits, for example, as shown in FIG.
Two drive circuits 221 and 222 are connected by a bridge connector 36, and an image signal 9□ is continuously sent from one serial input terminal 23. Other drive circuit 22
3.224...22, the image signals 92 to 9. ．． Send 7□. In another model, the number of connected drive circuits is increased to four as shown in FIG. 5, and the image signal 9. In either case, as shown in FIG. 2, each drive circuit 22 synchronizes with the clock signal 18 and sequentially transfers the image signal so that the line buffer shown in FIG. 7,
．． 7□ Category C Sofa 8 Tsuta Tsuta ~ 8 +11%82
The capacity of 1 to 82 h may be selected and operated accordingly.

By doing this, the substrate 21 shown in FIG.
The signal input line 31 formed above is selectively used, and the number of leads connected to the terminal 32 can be reduced accordingly.

The signal processing circuit and the like can be simplified by reducing the number of partitioned buffers accordingly.

Therefore, if the rotational speed of the photosensitive drum is taken into account, and it is sufficient even if the signal transfer speed is slow, reliability can be improved by increasing the number of drive circuit connections as shown in Figure 6 or even more to reduce the number of lead wires. It is possible to improve the

Conversely, if high-speed signal transfer is required depending on the model, the number of lead wires can be increased. Although the optical writing head used for copying large-scale drawings has a significantly large number of light emitting elements and a large number of drive circuits, the present invention makes it possible to select various usage methods with a certain standard.

"Modifications" The optical writing head of the present invention is not limited to the following two embodiments.

It is not always necessary to use connectors as shown in the drawings to connect drive circuits to each other.

For example, when manufacturing optical writing heads, all drive circuits are connected in series using jumper wires that are easy to cut.
This jumper wire may be cut and used as necessary.

Furthermore, the capacity and configuration of one drive circuit may be replaced as appropriate with one that performs similar operations.

Furthermore, this optical writing head can be used not only for writing on a photosensitive drum, but also for writing image signals on various photosensitive bodies.

[Effects of the Invention] In the optical writing head of the present invention as described above, it is possible to easily connect or disconnect an appropriate number of shift registers in the drive circuit in series just by paying attention to the bridge connector or the like. Therefore, the number of lead wires can be reduced as much as possible within the allowable range. Further, there is no need to separate heads for each model, and parts can be made common.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of the uninvented optical writing head, Fig. 2 is a block diagram of its drive circuit, Fig. 3 is a side view of the main parts of its board, and Fig. 4 is a bridge connector and a block diagram of its drive circuit. FIGS. 5 and 6 are perspective views showing the relationship between the pins, FIGS. 5 and 6 are plan views of the main parts of the substrate, respectively, illustrating how to use the optical writing head of the invention, and FIG. 7 is a diagram showing the implementation of the optical writing head of the invention. FIG. 8 is a block diagram of a conventional printer from a signal processing circuit to an optical writing head, and FIG. 9 is a block diagram of the main parts thereof. 2... Optical writing head, 2□... Substrate, 2□... Light emitting element, 22... Drive circuit, 23... Shift Register, 231...Serial input terminal, 23o...
...Serial output terminal, 35...Pin, 36...Bridge connector. Applicant Fuji Xerox Co., Ltd.

Claims (1)

[Scope of Claims] 1. A large number of light emitting elements arranged in rows on a substrate, dividing these light emitting elements into a predetermined number of sections, and all the light emitting elements constituting each section. The drive circuit includes a shift register that receives image signals corresponding to the number of light emitting elements to be driven from a serial input terminal, and a drive circuit that selectively supplies driving pulses to the elements. What is claimed is: 1. An optical writing head comprising: a driver for supplying driving pulses to a light emitting element in accordance with the output voltage; and a serial output terminal for outputting an image signal input to a shift register. 2. A pin for attaching a bridge connector that electrically connects the two is embedded in one serial output terminal and the other serial output terminal of the drive circuits adjacent to each other. The optical writing head according to item 1. 3. A patent characterized in that the same number of adjacent drive circuits are connected in series to each other via their serial input terminals and serial output terminals, and the image signal is supplied from one of the open serial input terminals. An optical writing head according to claim 1 or 2.