JPH0550651A - Printer - Google Patents

Abstract

PURPOSE:To enable an inverted image to be obtained by simple circuitry without inverting an image data signal to be supplied respectively to each EL element. CONSTITUTION:For image data signals D1-Dn to be supplied respectively to each EL element of a line head 31 composed by arranging continuously a plurality of EL elements r1-1n, an exclusive-OR circuit 32 which operates an exclusive-OR with a phase control signal PC controlling voltage to be impressed to one side electrode (q) of each EL element is provided and besides, an inverting circuit 34 which inverts the phase control signal to be inputted to the exclusive-OR circuit is provided to select signal reacting operation with this inverting circuit by action of a switch 36 varying by input with a key.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer in which a plurality of electroluminescence elements (hereinafter referred to as EL elements) are continuously arranged to form a line head.

[0002]

2. Description of the Related Art In a conventional printer of this type, when a grayscale inversion image is to be obtained with a black-and-white inversion image or an image which can express gradation, image data supplied to a large number of EL elements forming a line head, respectively. I had to invert all the signals.

[0003]

As described above, conventionally, in order to obtain a reversed image, a large number of Es forming a line head are used.
All the image data signals supplied to the L elements must be inverted, and circuits for inverting each image data signal are required for the number of EL elements, which increases costs and scales with an increase in the number of parts. There were problems such as upsizing.

Therefore, the present invention is intended to provide a printer capable of obtaining an inverted image with a simple circuit configuration without inverting the image data signal supplied to each EL element.

[0005]

The present invention is directed to a plurality of ELs which emit light when a voltage higher than a threshold voltage is applied between both electrodes.
In a printer in which elements are continuously arranged to form a line head, a phase control signal for controlling a voltage applied to one electrode of each EL element with respect to an image data signal supplied to each EL element An exclusive OR circuit that respectively calculates an exclusive OR, an inverting circuit that inverts the phase control signal that is input to the exclusive OR circuit, and a selection unit that selects a signal inverting operation by the inverting circuit. Be prepared.

[0006]

According to the present invention having such a configuration, when the signal inverting operation by the inverting circuit is selected by the selecting means, each EL
The phase control signal input to the exclusive OR circuit that calculates the exclusive OR of the phase control signal that controls the voltage applied to one electrode of the element and the image data signal that is supplied to each EL element. Is reversed, and a grayscale inversion image is obtained in a black-and-white inversion image or a grayscale inversion image.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a non-impact printer for printing black and white images will be described below with reference to the drawings.

FIG. 1 is a view showing the arrangement of a non-impact printer, in which a photosensitive drum 2 is arranged at a substantially central portion of a casing 1 which is axially supported at one end and is vertically separable at the other end. The photoconductor drum 2 is rotationally driven in one direction by a drive motor 3, that is, in the clockwise direction in the figure, and the periphery of the photoconductor drum 2 is charged on the surface of the photoconductor drum 2 according to an electrophotographic process. The charging charger 4, an exposure device 5 that irradiates the photosensitive drum 2 charged by the charging charger 4 with light to expose and record image data, and a developer on the photosensitive drum 2 exposed by the exposure device 5. A developing device 6 for adhering a certain toner, a transfer charger 7 for transferring the toner image on the photoconductor drum 2 to a conveyed sheet, a cleaning device 8 for removing the toner from the photoconductor drum 2, and a charge erasing charger 9 for destaticizing the photoconductor drum 2. Are arranged in order.

The transfer charger 7 is located below the photosensitive drum 2, and a pickup roller 11 operates from a paper feed cassette 10 provided on one side of the housing 1 toward the transfer charger 7. The sheets are conveyed one by one at a predetermined timing.

After the toner image on the photosensitive drum 2 is transferred by the transfer charger 7 to the conveyed paper, the fixing device 1 is provided.
It is supposed to be fixed at 2. Then, the fixed paper is ejected to the outside of the housing by the paper ejection roller 13. Here, the drive motor 3 which is the drive source of the photosensitive drum 2 is also used as the drive source of the paper transport mechanism.

In addition to the above, a fan 14 for radiating internal heat to the outside, a power supply device 15, and a cover switch 16 for detecting when the housing 1 is vertically separated and turning off the power. Etc. are provided.

As shown in FIG. 2, a liquid crystal display 21 for displaying the number of printed sheets, messages, etc., an LED (light emitting diode) 22 for displaying the on / off state of the power source, Print start key 2 for instructing to start printing
3. An operation panel 20 provided with an inversion key 24 for instructing printing of a black and white inverted image is provided.

FIG. 4 is a circuit diagram showing the structure of the exposure apparatus 5. That is, the exposure apparatus 5 includes a pair of electrodes p,
A plurality of EL elements r1, r2, r3, ..., Rn having q
Of the EL elements r1 to rn.
An exclusive OR circuit for calculating an exclusive OR of each of the image data signals D1 to Dn supplied to each of the EL elements r1 to rn and a phase control signal PC for controlling a voltage applied to one electrode q of each of the EL elements r1 to rn. 32 and output signals s for the EL elements r1 to rn of the exclusive OR circuit 32.
1 to sn are converted into signals of a predetermined voltage level and applied to one electrode q of each of the EL elements r1 to rn, and a phase control signal PC input to the exclusive OR circuit 32 is inverted. And an inverting circuit 34.

The inverting circuit 34 has the phase control signal P.
A two-input exclusive OR gate 35 having C as one input is provided. A switch 36 that opens the other input of the exclusive OR gate 35 when the inversion key 23 is ON is set to "0" (phase control). The signal S is not inverted) and "1" (the phase control signal S is inverted).
Here, the inversion key 23 constitutes selection means for selecting the inversion operation of the phase control signal PC by the inversion circuit 34.

In the EL element, when an AC power supply pulse is applied between the electrodes p and q as shown in FIG. 3A, the voltage E between the electrodes is a positive side threshold voltage + A (V) or a negative side threshold voltage. The principle is that light is emitted toward the end face during a period exceeding the voltage −A (V). That is, in FIG. 3B, the period T
Light is emitted during 1 and the period T2, and is not emitted during the periods T3 and T4.

Therefore, in this embodiment, the other electrode p of the EL elements r1 to rn constituting the line head 31 is used.
As shown in FIG. 5A, a positive pulse less than the positive side threshold voltage + A and a negative pulse less than the negative side threshold voltage −A are alternately applied at a constant period.

Further, as shown in FIG. 5 (b), a phase control signal PC which repeats high level (+ 5V) and low level (0V) in a constant cycle, and the phase control signal PC shown in FIG. 5 (c). The conversion circuit 33 to which the exclusive OR output signals s1 to sn with the image data signals D1 to Dn that change to the high level or the low level in synchronization with the PC are input is shown in FIG.
When the exclusive OR output is “1” as shown in (d) +
The signal is converted into a signal of B (V), and when it is "0", it is converted into a signal of -C (V).

In such a structure, the reverse key 2 is now used.
When 3 is in the OFF state, the switch 36 of the inverting circuit 34 is closed and the other input of the exclusive OR gate 35 is "0", so that the phase control signal PC shown in FIG. It is given to the logical sum circuit 32.

At this time, for example, when the image data signal D1 shown in FIG. 5C is applied to the EL element r1, the conversion circuit 3 supplied to one electrode q of the EL element r1.
The output of 3 changes as shown in FIG. 5 (d), and the voltage signal shown in FIG. 5 (a) is supplied to the other electrode p of the EL element r1. Figure 5 shows the potential difference
It changes as shown in (e). As a result, in the period t3, the potential difference between the electrodes p and q is the negative threshold voltage −A.
Since the voltage exceeds (V), the EL element r1 emits light. In the period t5, the potential difference between the electrodes p and q exceeds the positive side threshold voltage + A (V), so that the EL element r1 also emits light.

On the other hand, when the inversion key 23 is in the ON state, the switch 36 of the inversion circuit 34 is open and the other input of the exclusive OR gate 35 is "1".
The level of the phase control signal PC shown in FIG.
It is given to the exclusive OR circuit 32 as a signal shown in (c).

At this time, the EL element r1 shown in FIG.
When the image data signal D1 shown in FIG. 6C similar to FIG. 6C is given, the output of the conversion circuit 33 supplied to one electrode q of the EL element r1 is as shown in FIG. 6D. 6 (a) on the other electrode p of the EL element r1.
Since the voltage signal shown in FIG. 6 is supplied, the potential difference between the electrodes p and q changes as shown in FIG. As a result, in the period t1, the potential difference between the electrodes p and q exceeds the positive side threshold voltage + A (V), so that the EL element r1 emits light. In the period t7, the potential difference between the electrodes p and q exceeds the negative side threshold voltage −A (V), so that the EL element r1 also emits light. The above operation is performed by another EL element r
The same applies to 2 to rn.

Therefore, as can be seen by comparing FIGS. 5 (e) and 6 (e), by turning on the reversing key 23, the light emitting operation of each of the EL elements r1 to rn is reversed, and the image data signal D1 is obtained. A black-and-white inverted image with respect to Dn is obtained.

As described above, according to the present embodiment, the inverting circuit 34 for inverting the phase control signal PC for controlling the voltage applied to one electrode q of each of the EL elements r1 to rn, and the signal inverting of the inverting circuit 34. A black-and-white inverted image can be obtained with a simple configuration in which an inversion key 23 for selecting an operation is added, and it is possible to improve the function while suppressing an increase in cost and an increase in scale due to an increase in the number of parts. ..

The present invention is not limited to the above-mentioned embodiment, and for example, in the case of gradation expression, by applying the present invention, a grayscale inversion image can be obtained with a simple structure.

Further, although the inversion key 23 is shown as the selection means for selecting the signal inversion operation by the inversion circuit 34, it goes without saying that means other than the key can be used. Further, the switch 36 may be automatically controlled to be opened / closed in response to a reverse image output command from the host device. Of course, various modifications can be made without departing from the scope of the present invention.

[0026]

As described in detail above, according to the present invention, an inverted image can be obtained with a simple circuit configuration without inverting the image data signal supplied to each EL element, which is low in cost and small in size. In addition, a high-performance printer can be provided.

[Brief description of drawings]

FIG. 1 is a structural diagram of a non-impact printer that is an embodiment of the present invention.

FIG. 2 is a diagram showing an operation panel in the embodiment.

FIG. 3 is a diagram used for explaining a light emitting principle of an EL element.

FIG. 4 is a circuit configuration diagram of an exposure apparatus in the embodiment.

FIG. 5 is a timing chart of main signals when a normal image is output in the embodiment.

FIG. 6 is a timing chart of main signals when a reverse image is output in the embodiment.

[Explanation of symbols]

23 ... Inversion key, 31 ... Line head, 32 ... Exclusive OR circuit, 33 ... Conversion circuit, 34 ... Inversion circuit.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G09F 9/30 365 D 7926-5G

Claims (1)

[Claims] 1. A printer in which a line head is formed by continuously arranging a plurality of electroluminescent elements that emit light when a voltage higher than a threshold voltage is applied between both electrodes, wherein each electroluminescent element is a line head. An exclusive OR circuit for calculating an exclusive OR of each of the image data signals supplied to each of the electroluminescent elements and the phase control signal for controlling the voltage applied to one electrode of each electroluminescence element, and the exclusive OR circuit. A printer comprising: an inverting circuit that inverts the phase control signal input to the summing circuit; and a selection unit that selects a signal inverting operation by the inverting circuit.