JP2866776B2 - Non-impact printer and printing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-impact printer and a printing method thereof.

[0002]

2. Description of the Related Art Conventionally, in a non-impact printer such as an electrophotographic printer, an electrostatic latent image is formed on the surface of a charged photosensitive drum by irradiating the charged photosensitive drum with a light source, and toner is attached to the electrostatic latent image. Then, a toner image is formed by performing development, and the formed toner image is transferred and fixed on paper.

FIG. 2 is a block diagram of a control circuit of a conventional non-impact printer, FIG. 3 is a time chart of the conventional non-impact printer, and FIG. 4 is a block diagram of an LED head in the conventional non-impact printer. FIG.
Wherein 1 is a microprocessor, ROM, RAM,
A printing control unit including an input / output port, a timer, and the like. The printing control unit is provided in a printing unit of the non-impact printer.
The printing operation is performed by sequence-controlling the entire printing unit by, for example,. When a print instruction is received by the control signal 10, the print controller 1 first detects whether or not the fixing device 22 having the built-in heater 22a is in a usable temperature range by the fixing device temperature sensor 29. If not, the heater 22a is turned on by the signal 21, and the fixing device 22 is heated to a usable temperature. Next, the developing / transfer process motor (PM) 3 is rotated via the driver 2, and at the same time, the charging high voltage power supply 25 is turned on by the charge signal 23 to charge the developing device 27.

Then, the type of the set sheet is detected by the sheet remaining amount sensor 8 and the sheet size sensor 9, and the sheet feeding corresponding to the sheet is started. Here, the paper feed motor (PM) 5 can rotate bidirectionally via the driver 4, and rotates in the reverse direction first, and sets the paper set in advance until the paper inlet sensor 6 detects the paper. Send only the amount. Subsequently, the paper rotates forward and conveys the paper into the printing mechanism inside the non-impact printer.

When the paper reaches the printable position, the print control unit 1 transmits a timing signal 12 (including a line timing signal and a raster timing signal) to the host controller and receives the video signal 11. I do. Edited for each page in the host controller,
The video signal 11 received by the print control unit 1 is used as the head data signal 18 together with the clock signal 18a as L
The data is transferred to the ED head 19.

Referring to FIGS. 3 and 4, an LED head 19 is shown.
Is a shift register 19a for sequentially storing the head data signal 18 for one line from the print control unit 1 (FIG. 2) by a clock signal 18a, and latching the head data signal 18 for one line stored in the shift register 19a. A latch 19b temporarily held by the signal 17, an LED group 19c in which the number of LED light emitting elements corresponding to the number of dots for one line are arranged, and a head data signal 18 held in the latch 19b are output to the LED group 19c. Driver group 19d.

A shift register 19a in the LED head 19 converts the head data signal 18 into a clock signal 18a.
Are sequentially stored. When receiving the video signal 11 for one line, the print control unit 1 sends a latch signal 17 to the LED head 19. The latch 19b in the LED head 19 holds the head data signal 18 for one line stored in the shift register 19a by the latch signal 17. The held head data signal 18 is
Before receiving the video signal 11 for the next one line, it is sent to the LED group 19c by the print drive signal 13 sent from the host controller, and the corresponding LED light emitting element emits light.

The transmission and reception of the video signal 11 is performed for each print line. The head data signal 18 transferred to the LED head 19 is formed into a latent image as a dot having an increased potential on the photosensitive drum charged to a negative potential. Then, in the developing device 27, the toner for image formation charged to a negative potential is attracted to each dot by an electric attraction force to form a toner image, and the toner image is sent to the transfer device 28.

On the other hand, the transfer high voltage power supply 26 having a positive potential is turned on by the transfer signal 24, and the transfer unit 28 transfers the toner image onto a sheet passing through the gap between the photosensitive drum and the transfer unit 28. . The sheet having the transferred toner image is conveyed while being in contact with a fixing device 22 having a built-in heater 22a, and the toner image is fixed by the heat of the fixing device 22. Then, the sheet having the fixed toner image is further conveyed and discharged from the printing mechanism through the sheet discharge sensor 7 to the outside of the non-impact printer.

The print control unit 1 transfers the voltage from the transfer high-voltage power supply 26 only when the sheet is passing through the transfer unit 28 in response to the detection of the sheet size sensor 9 and the sheet inlet sensor 6. To the vessel 28. When the printing is completed and the sheet passes through the sheet outlet sensor 7, the application of the voltage to the developing device 27 by the charging high-voltage power supply 25 is terminated.
At the same time, the rotation of the developing / transfer process motor 3 is stopped.

Thereafter, the above operation is repeated.

[0012]

However, in the conventional non-impact printer, dots of the same size are printed on paper with the resolution of the LED head 19, that is, the distance between the LED light emitting elements in the raster direction. Therefore, a jagged feeling due to the resolution remains in the hatched portion of the printed image.

FIG. 5 is a diagram showing a printing state by a conventional non-impact printer, and FIG. 6 is a diagram showing another printing state by a conventional non-impact printer. 5A and 6A show 300 DPI data, FIG. 5B shows print timing and LED head drive energy, and FIG. 5C shows an actual print image. As shown in the figure, since printing is performed on each raster line, a jagged feeling remains in the hatched portion of the printed image. Therefore, in order to increase the dot density in order to improve the print quality, it is necessary to use the LED head 19 in which the interval between the LED light emitting elements is reduced. However, LE with a narrower interval between LED light emitting elements
The D head 19 has a low production yield at the portion where the LED light emitting elements are arranged, and is very expensive.

The present invention solves the problem of the conventional non-impact printer and can receive even when the resolution of the video signal received from the host controller is higher than the resolution of the printing unit (the arrangement pitch of the LED light emitting elements). And L
An inexpensive non-impact printer capable of increasing the density of dots apparently higher than the distance between the ED light emitting elements, reducing the jaggedness of the hatched portion of the printed image, improving the print quality, and reducing the cost. It is intended to provide a printing method.

[0015]

In order to achieve the object, a non-impact printer according to the present invention comprises a print head in which print elements are arranged in a predetermined direction, and a print head which receives a video signal continuously in the predetermined direction. A first converter for taking a logical product of the bit data to be generated and generating a first signal for printing on a first line along the predetermined direction; To take an exclusive OR of consecutive bit data, and to print on a second line along the predetermined direction.
And a drive energy setting means for independently setting drive energy for printing on the first line and drive energy for printing on the second line. Have. In another non-impact printer of the present invention, a line timing signal for printing on a basic raster line is generated, and an additional line timing signal for printing on an additional raster line is provided between each timing of the line timing signal. Is provided.

When the received video signal has a higher resolution than the resolution of the LED head, a logical product of bit data continuous in the raster direction of the video signal is obtained, and a data string corresponding to the resolution of the LED head is obtained. It is converted into a composed first signal. A means is provided for transferring the first signal to the LED head as a head data signal for printing on a basic raster line in correspondence with the line timing signal.

The exclusive OR of bit data continuous in the raster direction of the video signal is taken and converted into a second signal composed of another data string, and the second signal is sent to a line buffer. Output to Means are provided for transferring the second signal in the line buffer to the LED head as a head data signal for printing on an additional raster line in correspondence with the additional line timing signal.

L for printing on the basic raster line
The ED head drive energy and the LED head drive energy for printing on the additional raster line are set independently. The logical product of bit data continuous in the raster direction of the video signal can be printed on an additional raster line, and the exclusive logical sum of bit data continuous in the raster direction of the video signal can be printed on a basic raster line.

Further, the video signal of the same line is received twice, the logical product of the bit data continuous in the raster direction is first printed, and then the exclusive logical sum of the bit data continuous in the raster direction is obtained. Can also be printed. Further, LE when printing with the first signal obtained by taking the logical product is used.
The driving energy of the D head can be made larger than the driving energy of the LED head when printing with the second signal obtained by taking the exclusive OR.

In the printing method of the non-impact printer of the present invention, n dots are formed by printing elements arranged along a predetermined direction based on 2n bit data of a received video signal. Has become.
Then, if both bit data of two consecutive bit data of the received video signal along the predetermined direction have a value corresponding to a dot to be printed, the first print data is output. , When only one of two consecutive bit data of the video signal along the predetermined direction has a value corresponding to a dot to be printed,
The second print data is output, and relatively large dots are formed corresponding to the first print data, and relatively small dots are formed corresponding to the second print data.

[0021]

According to the present invention, in the non-impact printer as described above, the first converter takes the logical product of the bit data continuous along the predetermined direction of the received video signal, and A first signal for printing a first line along a direction is generated.
Further, the second converter takes an exclusive OR of bit data continuous along the predetermined direction of the received video signal, and prints on a second line along the predetermined direction. A second signal is generated.
The driving energy setting means sets the driving energy for printing on the first line and the driving energy for printing on the second line independently. In another non-impact printer of the present invention, a line timing signal for printing on a basic raster line is generated, and an additional line timing signal for printing on an additional raster line is output between each timing of the line timing signal. A generating means is provided, and printing is performed twice for each line.

When the received video signal has a higher resolution than the resolution of the LED head, a logical product of bit data continuous in the raster direction of the video signal is obtained, and a data string corresponding to the resolution of the LED head is obtained. It is converted into a composed first signal. The first signal is transferred to the LED head as a head data signal for printing on a basic raster line in accordance with the line timing signal. The LED head prints on the basic raster line for the first signal in the first printing.

On the other hand, the exclusive OR of bit data continuous in the raster direction of the video signal is taken and converted into a second signal composed of another data string, and the second signal is sent to the line buffer. Output to Then, the second signal in the line buffer is transferred to the LED head as a head data signal for printing on an additional raster line, corresponding to the additional line timing signal. The LED head prints on the additional raster line for the second signal in the second printing.

L for printing on the basic raster line
The ED head drive energy and the LED head drive energy for printing on the additional raster line are set independently. The logical product of bit data continuous in the raster direction of the video signal can be printed on an additional raster line, and the exclusive logical sum of bit data continuous in the raster direction of the video signal can be printed on a basic raster line.

Also, the video signal of the same line is received twice, and the logical product of the bit data continuous in the raster direction is printed first, and then the exclusive logical sum of the bit data continuous in the raster direction is obtained. Can also be printed. Further, LE when printing with the first signal obtained by taking the logical product is used.
The driving energy of the D head can be made larger than the driving energy of the LED head when printing with the second signal obtained by taking the exclusive OR.

According to the printing method of the non-impact printer of the present invention, n dots are formed by printing elements arranged along a predetermined direction based on 2n bit data of a received video signal. Has become.

[0027] If both bit data of two consecutive bit data of the received video signal along the predetermined direction have a value corresponding to a dot to be printed, the first print data And outputting only the second print data when only one of two consecutive bit data of the video signal along the predetermined direction has a value corresponding to a dot to be printed, Forming relatively large dots corresponding to the first print data;
A relatively small dot is formed corresponding to the second print data.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of a control circuit of a non-impact printer according to a first embodiment of the present invention,
FIG. 7 is a block diagram of a print data receiving circuit of a non-impact printer according to a first embodiment of the present invention, FIG. 8 is a time chart of the print data receiving circuit in the first embodiment of the present invention, and FIG. FIG. 10 is an enlarged view of a time chart of the print data receiving circuit in the first embodiment of the present invention, FIG. 10 is a diagram showing bit data based on a received video signal in the first embodiment of the present invention, and FIG. FIG. 12 is a diagram showing bit data according to a head data signal in the embodiment, FIG. 12 is a diagram showing a printing state by a non-impact printer according to the first embodiment of the present invention, and FIG.
FIG. 14 is a diagram illustrating another printing state by the non-impact printer in the example of FIG. (A) of FIGS.
0DPI data, (b) shows print timing and LED head drive energy, and (c) shows an actual print image.

In the figure, 1 is a microprocessor, R
A print control unit configured by an OM, a RAM, an input / output port, a timer, or the like, or a logic circuit having an equivalent function. The print control unit is provided in a print unit of a non-impact printer. Control signal 1 from the controller)
0, the printing unit of the printer is sequence-controlled by the video signal 11 and the like, and the printing operation is performed. When a print instruction is received by the control signal 10, the print controller 1 first detects whether or not the fixing device 22 having the built-in heater 22a is in a usable temperature range by the fixing device temperature sensor 29. If not, the heater 22a is turned on by the signal 21, and the fixing device 22 is heated to a usable temperature. Next, the developing / transfer process motor (PM) 3 is rotated via the driver 2, and at the same time, the charging high voltage power supply 25 is turned on by the charge signal 23 to charge the developing device 27.

Then, the type of the set sheet is detected by the sheet remaining amount sensor 8 and the sheet size sensor 9, and the sheet feeding corresponding to the sheet is started. Here, the paper feed motor (PM) 5 can rotate bidirectionally via the driver 4, and rotates in the reverse direction first, and sets the paper set in advance until the paper inlet sensor 6 detects the paper. Send only the amount. Subsequently, the paper rotates forward and conveys the paper into the printing mechanism inside the non-impact printer.

Here, the resolution (array pitch of the LED light emitting elements as the printing elements) of the LED head 19 as the print head in the printing section of the non-impact printer in the raster direction (raster scanning line direction) is 300 DPI, and the video signal to be received. 11 is 600 DPI, the resolution of the actual print image is 300 DPI in the raster direction, and 1200 DPI (pseudo 600 DP) in the print direction (paper transport direction).
The case of printing in I) will be described.

When the paper reaches the printable position, the print control unit 1 sends a timing signal 12 to the host controller.
(Including the line timing signal 12a and the raster timing signal) and the video signal 11 is received. In the upper controller, the vertical and horizontal 6 edited for each page
As shown in FIGS. 7 to 9, the 00DPI video signal 11 is supplied to flip-flops 51 and 52 of the resolution conversion block.
The signal is converted into a first signal a by a first converter including an AND (AND) circuit 53, and is output as a head data signal 18 via a selector 57 as a head data signal 18 for printing on a basic raster line as a first raster line. The data is transferred to the head 19. At the same time, the second signal b converted by the exclusive OR (exclusive OR) circuit 54 as a second converter is added to an additional raster as a second raster line formed between basic raster lines. It is stored in a line buffer 56 via a selector 55 for printing on a line.

Here, 58 is a clock signal generation circuit, and 6
0 is a delay circuit, 62 is a line timing signal generation circuit,
Numeral 61 denotes a frequency multiplier that doubles the frequency of the line timing signal 12a generated by the line timing signal generating circuit 62, and numeral 63 denotes an AND circuit. The multiplier 61 generates an additional line timing signal 12c for printing on an additional raster line during each timing of the line timing signal 12a. For the video signal transfer clock signal 12b output from the printing unit to the host controller, the clock signal 18a is obtained by frequency-dividing the clock generated by the clock signal generation circuit 58 by two by the flip-flop 59.
0 to the LED head 19.

Next, a signal obtained by the print data receiving circuit will be described. Since the first signal a is the logical product of the outputs of the flip-flops 51 and 52, the first bit data is 6 bits as shown in FIG.
The logical product of the first and second bit data of the 00 DPI video signal 11 is the logical product of the second and third bit data, and so on. This first signal a is transferred to the LED head 19 via the selector 57 as the head data signal 18, but the clock signal 18a
Is output in synchronism with the odd-numbered bit data of the head data signal 18 by the flip-flop 59 and the delay circuit 60.
The bit data sequentially stored in a (see FIG. 4) is only the odd-numbered bit data of the head data signal 18. Therefore, what is printed on the basic raster line is the logical product of the first and second bit data of the video signal 11, the logical product of the third and fourth bit data,.
+ 1st and 2n + 2th (n = 0, 1, 2,..., 255
The logical product of the bit data of 9) is obtained.

The second signal b is supplied to the flip-flop 5
1 and the exclusive OR of the flip-flop 52,
As shown in FIG. 9, the first bit data is 600 DPI.
, And the second bit data is the exclusive OR of the second and third bit data,.... The second signal b is stored in the line buffer 56 via the selector 55, read out as the signal c via the selector 55 when printing on the additional raster line, and is output as the head data signal 18 via the selector 57 as the LED head. Transferred to 19. Also in this case, the clock signal 18a is sent to the LED head 19 in synchronization with the odd-numbered bit data of the head data signal 18 as in the case of printing on the basic raster line.
Are sequentially stored in the head data signal 1
Only the odd-numbered bit data of 8 becomes. Therefore,
One of the video signals 11 is printed on the additional raster line.
Exclusive OR of the 3rd and 4th bit data,..., 2n + 1st and 2n + 2nd (n = 0, 1, 2,..., 2559) bit data Exclusive OR of ...

Then, for example, as shown in FIG.
In the video signal 11 received at 0 DPI, as shown in FIG. 11, bit data of the logical product of the odd-numbered bit data and the even-numbered bit data of the video signal 11 is printed on the basic raster line, and Prints the bit data of the exclusive OR of the odd-numbered bit data and the even-numbered bit data. That is, S in FIG.
_1-bit data is converted into bit data of S ₂ in FIG. 11.

When the print control unit 1 transfers the head data signal 18 for one line to the LED head 19,
The latch signal 17 is transmitted to the head 19, and the odd-numbered bit data of the converted head data signal 18 is held in the LED head 19. The LED head 19 has a large number of LED light emitting elements arranged in a raster direction. When the print drive signal 13 is received, the LED head 19 is driven with the LED head drive energy E1 by the held bit data,
An electrostatic latent image is formed on the photosensitive drum.

Next, the sheet is moved in the sheet conveying direction to 1/1200.
When the print control unit 1 reaches a position separated by inches, the print control unit 1 extracts the bit data (signal c) stored in the line buffer 56 by switching the selectors 55 and 57, and sends the head data signal 18 to the LED head 19 by the clock signal 18a. Transfer as At this time, the line timing signal 12a to the host controller is not generated, and the above operation is performed only by the printing unit.

Then, the print control unit 1 transmits a latch signal 17 to the LED head 19 and causes the LED head 19 to hold the bit data. When receiving the print drive signal 13, the LED head 19 is driven by the LED head drive energy E2 by the odd-numbered bit data of the held head data signal 18, and forms an electrostatic latent image on the photosensitive drum.

Then, in the developing unit 27, the toner for image formation charged to a negative potential is attracted to each dot by an electric attraction force, a toner image is formed, and the toner image is sent to the transfer unit 28. On the other hand, the transfer high voltage power supply 26 having a positive potential is turned on by the transfer signal 24, and the transfer unit 28 transfers the toner image onto a sheet passing through the gap between the photosensitive drum and the transfer unit 28.

The paper having the transferred toner image is conveyed while being in contact with a fixing device 22 having a built-in heater 22a, and the toner image is fixed by the heat of the fixing device 22. Then, the sheet having the fixed toner image is further conveyed and discharged from the printing mechanism through the sheet discharge sensor 7 to the outside of the non-impact printer. The print control unit 1 includes a paper size sensor 9, a paper inlet sensor 6,
, The voltage from the transfer high-voltage power supply 26 is applied to the transfer unit 28 only while the sheet is passing through the transfer unit 28. When the printing is completed and the paper passes through the paper outlet sensor 7, the application of the voltage to the developing device 27 by the charging high-voltage power supply 25 is terminated, and at the same time, the rotation of the developing / transfer process motor 3 is stopped.

Thereafter, the above operation is repeated. Here, the drive energy setting means (not shown) of the print control unit 1
As shown in FIGS. 12 and 13, the drive energy for each line, that is, the LED head drive energy E1 and E2 is equivalent to the dot image formed in the printing at the pseudo 600 DPI as in the printing at the basic 300 DPI. Set to be.

Then, as shown in FIG.
Line L 300 inches away₁, L _TwoBasic rasterizer on
Printing with the LED head drive energy E1
LED head drive energy E2 for added raster line
Printing is performed. The actual print image at this time is
Printing section such as A-A or C-C
BB in minutes and in additional raster lines
It is formed by a printed portion as shown by.

In this embodiment, since the conversion is performed so that the data at the position 1200 DPI apart increases, E1> E2 is set, and the necessary LED head driving energies E1, E
2 differs depending on the characteristics of the developing device 27, the lens, and the toner, but with respect to the LED head driving energy E at the standard of 300 DPI, E1 = (0.4 to 0.6) × E E2 = (0.15 to 0. 25) It is set to be xE.

Next, a method for printing at a resolution higher than the resolution of the LED head 19 will be described with reference to FIGS. FIG. 14 is a diagram showing print dots on a raster line and light emission intensity according to the first method.
FIG. 4 is a diagram showing print dots on a raster line and light emission intensity according to a second method.

In FIG. 14, the light emission intensity at the light emitting point of each LED light emitting element of the LED head 19 (FIG. 1) is:
Print dots are formed at each light emitting point position, sufficiently exceeding the sensitivity of the photosensitive drum. At this time, the light emission intensity at an intermediate portion of the light emitting point increases due to the light emission at the adjacent light emitting point, and exceeds the sensitivity intensity of the photosensitive drum necessary for forming an image. Is performed, adjacent dots are connected by a dot in an intermediate portion.

In FIG. 15, since the light emission intensity of each light emitting point alone does not exceed the sensitivity intensity of the photosensitive drum required for forming an image, no print dot is formed. On the other hand, when adjacent light-emitting points emit light at the same time, the combined light-emitting intensity exceeds the sensitivity of the photosensitive drum at the intermediate portion. Therefore, it is possible to form print dots in the intermediate portion. That is, printing can be performed with a resolution twice as high as the resolution of the printing unit.

FIG. 16 is a diagram showing the light emission intensity in the actual print image of FIG. (A) of the figure shows the print portion AA
, The emission intensity in the printed portion BB, and the emission intensity in the printed portion CC are shown in FIG. (A) of the figure shows an LED in the basic raster line.
It shows the light emission intensity when printing is performed with the head drive energy E1 (FIG. 12). A printed portion AA in the actual print image of FIG. 12 is formed in a portion exceeding the sensitivity intensity of the photosensitive drum.

FIG. 9B shows the state of L in the additional raster line.
It shows the light emission intensity when printing is performed using the ED head drive energy E2. The print portion BB in the actual print image of FIG.
Is formed. In this case, since the light emission intensity is maximized on the line L _1, L ₂ of the middle of the line L _3, it means that also form the printing dots on the line L ₃ (pseudo 60
0 DPI).

FIG. 7C shows L in the basic raster line.
It shows the light emission intensity when printing is performed using the ED head drive energy E1. The printed portion C-C in the actual print image of FIG.
Is formed. In the above-described embodiment, the logical product of the continuous bit data is taken by the print data receiving circuit, and the logical product is printed on the basic raster line, and the exclusive logical sum of the continuous bit data is taken, and the logical product is added to the additional raster line. In the print data receiving circuit, the logical product of the continuous bit data is taken, and it is printed on an additional raster line, and the exclusive OR of the continuous bit data is taken. It can also be printed on the line.

Next, a second embodiment of the present invention will be described. In the second embodiment, a line buffer for storing bit data for printing on an additional raster line is not provided. When printing on an additional raster line, a line timing signal 12a is transmitted to the host controller, and the same 600 DPI data as the basic raster line is received as a video signal 11 and converted into a head data signal 18.

FIG. 17 is a block diagram of a print data receiving circuit in a non-impact printer according to a second embodiment of the present invention, and FIG. 18 is an enlarged time chart of the print data receiving circuit according to the second embodiment of the present invention. FIG. In the figure, reference numerals 51, 52, and 59 denote flip-flops, 53 denotes an AND circuit, 54 denotes an exclusive OR circuit, 57 denotes a selector,
8 is a clock signal generation circuit, 60 is a delay circuit, 61 is a multiplier, and 62 is a line timing signal generation circuit.

When printing on a basic raster line, a line timing signal 12a that matches the timing signal 12 is transmitted to an upper controller (not shown), and bit data of the m-th line of 600 DPI data is transmitted as a video signal 11. The outputs from the flip-flops 51 and 52 are ANDed by the AND circuit 53 and output to the selector 57. At this time, the selector 57 selects the first signal a, which is the output from the AND circuit 53, and transfers it as the head data signal 18 to the LED head 19 (FIG. 1). The clock signal 18a is obtained by dividing the clock generated by the clock signal generation circuit 58 into two by the flip-flop 59, as in the first embodiment.
0 to the LED head 19. The clock signal 18a is synchronized with the odd-numbered bit data of the first signal a. Therefore, the same bit data as in the first embodiment is sent to the shift register 19a (see FIG. 4) of the LED head 19 and printed.

When printing on an additional raster line, a line timing signal 12 a is sent to the upper controller. At this time, the same m-th bit data as the data of the basic raster line is transmitted as the video signal 11 from the upper controller. The outputs from the flip-flops 51 and 52 are exclusive-ORed by an exclusive-OR circuit 54 and output to a selector 57. At this time, the selector 57
Selects the second signal b output from the exclusive OR circuit 54 and transfers it to the LED head 19 as a head data signal 18. Since the clock signal 18a is sent in the same manner as in the case of the basic raster line, printing is performed in the same manner as in the first embodiment.

As described above, even if the line buffer 56 (FIG. 7) is not provided in the print control unit 1, the same m-th line data is transmitted twice from the higher-level controller to achieve the same operation as in the first embodiment. Printing results can be obtained. In the above-described embodiment, the logical product of the continuous bit data is taken by the print data receiving circuit, and the logical product is printed on the basic raster line, and the exclusive logical sum of the continuous bit data is taken, and the logical product is added to the additional raster line. In the print data receiving circuit, the logical product of the continuous bit data is taken, and it is printed on an additional raster line, and the exclusive OR of the continuous bit data is taken. It can also be printed on the line.

By the way, in the above-described embodiment, the adjacent light emitting points are made to emit light at the same time, and the light emitting intensities are combined so that printing is performed in the middle of the light emitting points. become. Therefore, light having a broad emission intensity distribution must be used. However, if light having a wide spread of the light emission intensity is used, the print density varies greatly with respect to the light intensity.

That is, the broadened emission intensity distribution can be expressed by the following equation (1).

[0058]

(Equation 1)

Here, the equation (1) is generally known as an equation representing the emission intensity distribution of the laser beam, where P (x, y) is the emission intensity at coordinates (x, y), and A is the emission intensity P
Parameters related to (x, y), r is a parameter representing the spread of the emission intensity distribution, and these parameters A,
As r increases, the emission intensity P (x, y) increases and the spread also increases. _Assuming that printing is performed on a portion where the light emission intensity P (x, y) is _{equal to} or greater than the sensitivity intensity _{Eth of the} photosensitive drum, the printing area S is represented by Expression (2).

[0060] To examine the rate of change of the print area S with respect to a change in ^{S = πr 2/2 · (} logA-logE th) ... (2) parameters A, when partial differentiation with parameters A, .differential.S / ∂A = ( πr ^2/2) · to become (1 / a) ... (3 ). From the equation (3), the change in the print area S increases as the parameter r increases with respect to the change in the parameter A, that is, as the spread of the emission intensity distribution increases. As described above, the variation in the print density becomes large with respect to the variation in the light emission intensity P (x, y).

Thus, an embodiment will be described in which variations in print density can be reduced with respect to variations in light emission intensity P (x, y). FIG. 19 is a graph showing a relationship between a change in light emission intensity and a change in print density when the spread of the light emission intensity distribution is large.
FIG. 20 is a graph showing a relationship between a change in light emission intensity and a change in print density when the spread of the light emission intensity distribution is small.

In the drawing, only the emission intensity in the raster direction is shown, _Eth is the sensitivity intensity of the photosensitive drum, the solid line is the standard emission intensity, and the broken line is the emission intensity when it is larger than the standard. Also, w ₁ and w ₂ are the standard print width,
W ₁ and W ₂ are printing widths when the emission intensity is large. For example, if the light emission intensity varies and becomes larger than the standard, the print density when the spread of the light emission intensity is large is W
₁ / w ₁ only changed, also, the print density when the spread of the light emission intensity distribution is small changes by W ₂ / w _2.

Here, since W ₁ / w ₁ > W ₂ / w ₂ , it can be seen that when the spread of the emission intensity distribution is small, the variation in print density is small even if the emission intensity varies. FIG. 21 is a diagram showing the light emission intensity in the third embodiment of the present invention. (A) of the figure shows the luminous intensity when printing is performed at the middle part of the luminescent point, and (b) shows the luminous intensity when printing is performed at the luminescent point.

In the figure, P and Q are light emitting points on a raster line, E _th is the sensitivity of the photosensitive drum, and H is the distance between light emitting points. The solid line indicates the light emission intensity at each of the light emitting points P and Q, and the broken line indicates the combined light emission intensity. In this case, when compared with the luminous intensity distribution shown in FIG. 16, the light emitting points P, spreading of the emission intensity distribution of Q is set small and the maximum value of the emission intensity is set larger than the sensitive intensity E _th of the photosensitive drum ing. Then, the light emitting points P and Q in the composite light emission intensity distribution
Of it forms a trough in the middle part, the combined emission intensity of the intermediate portion can be made significantly print than sensitive intensity E _th of the photosensitive drum. Further, the light emitting point P, even if sensitive intensity E _th is smaller than the combined emission intensity photosensitive drum in the middle portion of the Q, if enough narrow width of the small portion is invisible is not on the print quality problem.

In order to reduce the spread of the light emission intensity distribution, the light emission points P and Q are sufficiently small with respect to the distance H between the light emission points, and the intermediate portion of the light emission points P and Q in the composite light emission intensity distribution, that is, the printing is performed. LED with valley formed in the center
Light emitting elements are used. Then, an optical system with a high resolution that can sufficiently resolve two adjacent light emitting points P and Q is used. However, when the light emitting points P and Q are extremely small, or when the resolution of the optical system is extremely high,
At the time of printing, the print dots are not connected, and the print quality is reduced.

Therefore, for example, in the case of the LED head 19 (FIG. 1) having a resolution of 300 DPI, each light emitting point P,
The size of Q is set to 48 × 48 [μm], and a rod lens array SLA20B manufactured by Nippon Sheet Glass Co., Ltd. having a high resolution MTF is used as an optical system for focusing light emitted from the LED light emitting element on the photosensitive drum. Good to use. In this case, the light emitting points P, because the spread of the emission intensity distribution of Q is small, it is necessary to increase the emission intensity, and the printing width w ₃ by the combined emission intensity as shown in (a) of FIG. (B) The print width w based on the light emission intensity of the light emitting point Q as shown in FIG.
It is easy to make ₄ equal.

It should be noted that the present invention is not limited to the above-described embodiments, but can be variously modified based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0068]

As described above in detail, according to the present invention, in the non-impact printer, the first converter converts the logical product of bit data continuous in a predetermined direction of a received video signal. A first signal is generated for printing on a first line along the predetermined direction. Also, the second converter takes an exclusive OR of bit data continuous along a predetermined direction of the received video signal, and prints a second line along the predetermined direction on a second line. Two signals are generated. Then, the driving energy setting means includes:
The driving energy for printing on the first line and the driving energy for printing on the second line are set independently. In this case, even if the resolution of the received video signal is higher than the resolution of the printing unit, printing can be performed on the second line based on the video signal. Therefore,
It is possible to reduce the jaggedness of the hatched portion of the formed image. In another non-impact printer of the present invention, when the resolution of the received video signal is higher than the resolution of the LED head, the logical product of bit data continuous in the raster direction of the video signal is taken and the first signal is used. The converted first signal is transferred to the LED head as a head data signal for printing on a basic raster line in correspondence with the line timing signal.

The exclusive OR of bit data continuous in the raster direction of the video signal is converted to a second signal and output to a line buffer. Then, the second signal in the line buffer is transferred to the LED head as a head data signal for printing on an additional raster line, corresponding to the additional line timing signal. Also, an LE for printing on the basic raster line is provided.
The D head drive energy and the LED head drive energy for printing on the additional raster line are set independently.

Therefore, even when the resolution of the received video signal is higher than the resolution of the printing unit, it is possible to print on the additional raster line based on the video signal, so that the jagged feeling of the hatched portion of the image can be reduced. .

In the printing method of the non-impact printer of the present invention, n dots are formed by printing elements arranged along a predetermined direction based on 2n bit data of a received video signal. Has become.
Then, if both bit data of two consecutive bit data of the received video signal along the predetermined direction have a value corresponding to a dot to be printed, the first print data is output. , When only one of two consecutive bit data of the video signal along the predetermined direction has a value corresponding to a dot to be printed,
The second print data is output, and relatively large dots are formed corresponding to the first print data, and relatively small dots are formed corresponding to the second print data. In this case, even if the resolution of the received video signal is higher than the resolution of the printing unit, printing can be performed on the second line based on the video signal. Therefore, it is possible to reduce the jaggedness of the hatched portion of the formed image.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control circuit of a non-impact printer according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a control circuit of a conventional non-impact printer.

FIG. 3 is a time chart of a conventional non-impact printer.

FIG. 4 shows an LED in a conventional non-impact printer
It is a block diagram of a head.

FIG. 5 is a diagram illustrating a printing state by a conventional non-impact printer.

FIG. 6 is a diagram showing another printing state by a conventional non-impact printer.

FIG. 7 is a block diagram of a print data receiving circuit of the non-impact printer according to the first embodiment of the present invention.

FIG. 8 is a time chart of the print data receiving circuit according to the first embodiment of the present invention.

FIG. 9 is an enlarged view of a time chart of the print data receiving circuit according to the first embodiment of the present invention.

FIG. 10 is a diagram showing bit data based on a received video signal in the first embodiment of the present invention.

FIG. 11 is a diagram illustrating bit data based on a head data signal according to the first embodiment of the present invention.

FIG. 12 is a diagram illustrating a printing state by the non-impact printer according to the first embodiment of the present invention.

FIG. 13 is a diagram illustrating another printing state by the non-impact printer according to the first embodiment of the present invention.

FIG. 14 is a diagram illustrating print dots on a raster line and light emission intensity according to the first method.

FIG. 15 is a diagram illustrating print dots on a raster line and light emission intensity according to a second method.

16 is a diagram showing the light emission intensity in the actual print image of FIG.

FIG. 17 is a block diagram of a print data receiving circuit in a non-impact printer according to a second embodiment of the present invention.

FIG. 18 is an enlarged view of a time chart of a print data receiving circuit according to a second embodiment of the present invention.

FIG. 19 is a graph showing a relationship between a change in emission intensity and a change in printing density when the spread of emission intensity distribution is large.

FIG. 20 is a graph showing a relationship between a change in light emission intensity and a change in print density when the spread of the light emission intensity distribution is small.

FIG. 21 is a diagram showing emission intensity in the third example of the present invention.

[Explanation of symbols]

11 video signal 12a line timing signal 12c additional line timing signal 18 the head data signals 19 LED head 56 line buffer a first signal b second signal P, Q emission point E _th sensitive strength E, E _1, E ₂ LED heads Drive energy

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/44 B41J 2/45 B41J 2/455

Claims (7)

(57) [Claims] 1. A print head in which printing elements are arranged along a predetermined direction, and (b) a logic of bit data of the received video signal which is continuous along the predetermined direction. Take the product in the direction
Along generating a first signal for printing the first line
A first converter that Ru is, along the predetermined direction of the video signal received (c)
Taking the exclusive OR of the bit data continuous Te, the plants
A second converter Ru generating a second signal for printing the second line along a constant direction, and drive energy for printing in (d) of the first line, the second non-impact printer, characterized in that it comprises a drive energy setting means is independently set by a drive energy for printing on the second line. Wherein (a) means for Ru generates a line timing signals for printing on basic raster lines, (b) during each timing of the line timing signal, additional lines for printing additional raster line take means for Ru generates a timing signal, a logical product of the bit data continuous in the raster direction of the video signal received (c), means for converting the first signal, (d) is the first signal, Means for transferring to the LED head as a head data signal for printing on a basic raster line in correspondence with the line timing signal; and (e) taking an exclusive OR of bit data continuous in the raster direction of the video signal. and means for outputting to the second transformation to the line buffer signal, a second signal in said line buffer (f), the additional Raintaimi Means for transferring to the LED head as a head data signal for printing on the additional raster line in accordance with the additional raster line; (g) LED head driving energy for printing on the basic raster line; Means for independently setting the driving energy of the LED head for printing. 3. (a) means for Ru generates a line timing signals for printing on basic raster lines, (b) during each timing of the line timing signal, additional lines for printing additional raster line take means for Ru generates a timing signal, a logical product of the bit data continuous in the raster direction of the video signal received (c), means for converting the first signal, (d) is the first signal, Means for transferring to the LED head as a head data signal for printing on an additional raster line in correspondence with the additional line timing signal; and (e) performing an exclusive OR operation on bit data continuous in the raster direction of the video signal. taken, and outputting to the second line buffer is converted to a signal, a second signal in said line buffer (f), the Raintaimi Means for transferring to the LED head as a head data signal for printing on the basic raster line in correspondence with the basic raster line; (g) LED head driving energy for printing on the basic raster line; Means for independently setting the driving energy of the LED head for printing. 4. (a) means for Ru generates a line timing signals for printing on basic raster lines, (b) during each timing of the line timing signal, additional lines for printing additional raster line means for Ru to generate a timing signal, receives the (c) a video signal, the raster direction of the video signal
ANDed bit data continuous to a means for converting the first signal, (d) said first signal, corresponding to the line timing signal, the head data for printing on the basic raster line means for transferring the LED head as a signal, received at different timings and the video signal of the (e) said video signal in the same line, the raster direction of the video signal
Taking the exclusive OR of the bit data continuous to a means for converting the second signal, (f) said second signal so as to correspond to the additional line timing signals, for printing additional raster line Means for transferring to the LED head as a head data signal; and (g) independently setting the LED head drive energy for printing on the basic raster line and the LED head drive energy for printing on the additional raster line. And a non-impact printer. 5. A (a) means for Ru generates a line timing signals for printing on basic raster lines during each timing (b) the line timing signal, additional lines for printing additional raster line means for Ru to generate a timing signal, receives the (c) a video signal, the raster direction of the video signal
ANDed bit data continuous to a means for converting the first signal, (d) said first signal, corresponding to the additional line timing signal, the head for printing additional raster line means for transferring a data signal to the LED head, received at different timings and the video signal of the (e) said video signal in the same line, the raster direction of the video signal
Taking the exclusive OR of the bit data continuous to a means for converting the second signal, (f) said second signal so as to correspond to line timing signal, the head for printing on the basic raster line Means for transferring to the LED head as a data signal; and (g) means for independently setting the LED head drive energy for printing on the basic raster line and the LED head drive energy for printing on the additional raster line. And a non-impact printer. 6. The LED head driving energy when printing with the first signal obtained by taking the logical product is made larger than the LED head driving energy when printing with the second signal taking the exclusive logical sum. The non-impact printer according to claim 2. 7. Based on the 2n-bit data received video signal, the printing element which are arranged along a predetermined direction
A non-impact printer printing method in which n dots are formed by a child, comprising: (a) both bits of two bit data of a received video signal that are continuous along the predetermined direction; data
But if it has a value corresponding to a dot to be printed, first
The outputs print data, (b) the only one of the two-bit data continuous predetermined along the direction of the video signal, if it has a value corresponding to a dot to be printed, the second Print data
Outputs, and characterized by forming the (c) the first print data in association to form a relatively large dot, (d) said second relatively small dots in correspondence with print data Non-impact printer printing method.