JP2866752B2 - Non-impact printer - 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.

[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 printer unit control circuit in a conventional non-impact printer, FIG. 3 is a time chart of the conventional non-impact printer, and FIG. 4 is a diagram showing print data during normal printing in the conventional non-impact printer. FIG. 5 is a diagram showing a print result of a conventional non-impact printer during normal printing, FIG. 6 is a diagram showing print data of a conventional non-impact printer during high-duty printing, and FIG. FIG. 9 is a diagram illustrating a printing result at the time of duty printing.

In FIG. 2, 1 is a microprocessor,
A control unit including a ROM, a RAM, an input / output port, a timer, and the like. The control unit is provided inside a printing unit of the printer. Perform printing operation. When a print instruction is received by the control signal 10, the control unit 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. For example, the heater 22a is turned on by the signal 21 to heat the fixing device 22 to a usable temperature. Next, the developing / transfer process motor (PM) 3 is rotated via the driver 2, and at the same time, the charge high voltage power supply 25
Is turned on 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 a printing mechanism inside the printer.

When the sheet reaches the printable point, the control unit 1 transmits a timing signal 12 (including a line timing signal and a raster timing signal) to the host controller and receives a video signal 11. The video signal 11 edited for each page in the host controller and received by the control unit 1 is transmitted to the print head 19 as an actual print data signal 18. And
Upon receiving the video signal 11 for one line, the control unit 1 sends a latch signal 17 to the print head 19 to hold the actual print data signal 18 in the print head 19. And before receiving the next data from the host controller,
The held actual print data signal 18 is printed by the print head 19 receiving the print drive signal 13.

The transmission and reception of the video signal 11 is performed for each print line. The information printed by the print head 19 is converted into a latent image as a dot having an increased potential on a photosensitive drum charged to a negative potential. Then, the toner for image formation charged to the negative potential is attracted to each dot by an electric attraction force, and a toner image is formed.

Thereafter, the toner image is sent to a transfer unit, and a transfer signal 24 turns on a high-voltage power supply 26 for transfer at a positive potential, and a transfer unit 28 transfers the toner image to the gap between the photosensitive drum and the transfer unit 28. Is transferred onto the paper passing through.
The sheet having the transferred image is transported in contact with the fixing device 22 having the heater 22a therein, and is fixed on the sheet by the heat of the fixing device 22. The sheet having the fixed image is further conveyed and discharged from the printer through the sheet discharge sensor 7 from the printing mechanism of the printer.

The control unit 1 controls the transfer device 28 in response to the detection of the paper size sensor 9 and the paper inlet sensor 6.
The voltage from the transfer high-voltage power supply 26 is applied to the transfer device 28 only during the passage through the transfer device. When the printing is completed and the paper passes through the paper outlet sensor 7, the application of the charging high voltage power supply 25 to the developing device 27 is completed, and the
The rotation of the transfer process motor 3 is stopped.

[0010] Here, when trying to express a gradation by a dither pattern, the number of dots printed in a unit area is increased or decreased according to the density of the image. In this case, the dots used for gradation expression and the dots constituting a part of characters, lines, and the like are set so that the driving energy at the time of printing has the same value. In addition, in the non-impact printer having the above configuration, when printing characters and the like, it is necessary to form continuous lines,
Rather than forming a single dot row, printing is performed so that adjacent dots overlap. For example,
When the print data is arranged as shown in FIG. 4, printing is performed so that adjacent dots overlap as shown in FIG.

[0011]

However, in the above-mentioned conventional non-impact printer, printing is performed for dots used for gradation expression, and printing is performed for dots constituting a part of characters, lines, and the like. Is set to the same value, if the drive energy for one print is set to the optimum value, the drive energy for the other will not be the optimum value, for example, the gradation expression will deviate greatly from the ideal one. May become darker.

Also, when performing high-duty printing, that is, when printing an image having a very large number of dots on a print screen, such as blank characters, the width of an unprinted portion becomes narrow or unprinted. An image becomes unclear due to discontinuous lines in the printing section, and the print quality is reduced. The present invention solves the above-mentioned problems of the conventional non-impact printer, performs gradation expression, and performs printing of characters, lines, and the like. An object of the present invention is to provide a non-impact printer capable of improving print quality during high-duty printing.

[0013]

For this purpose, in the non-impact printer of the present invention, an N-line buffer for storing video data signals of a plurality of N lines for each line and a reference line timing signal are generated. Means, means for generating an additional line signal between the timings of the reference line timing signal to divide the two basic raster lines into a plurality, and receiving the reference line timing signal to convert the video data signal. A selection circuit for selectively outputting to the N-line buffer.

The video data signal stored in the N-line buffer is received for a plurality of dots for each line, and the raster data in the dot area is compared with a predetermined dot pattern. In response to the above, a data signal for forming a dot on a basic raster line and a data signal for forming a dot on an additional raster line closer to the basic raster line from the center between two adjacent basic raster lines are generated. A logical operation circuit that generates and outputs each generated data signal as an actual print data signal by receiving the additional line signal, and receives the actual print data signal and the print drive signal, and is set for each line. And a print head that is driven for a predetermined driving time to perform exposure.

The driving time is determined separately for the basic raster line and the additional raster line, independently of the time for forming dots on the basic raster line and the time for forming dots on the additional raster line. Is set.

[0016]

According to the present invention, as described above, in a non-impact printer, an N-line buffer for storing video data signals of a plurality of N lines for each line, and means for generating a reference line timing signal are provided. Means for generating an additional line signal between the timings of the reference line timing signal in order to divide the two basic raster lines into a plurality, and receiving the reference line timing signal to convert the video data signal into the N And a selection circuit for selectively outputting to the line buffer. The above N
The video data signal stored in the line buffer is received for a plurality of dots for each line, and the raster data in the dot area is compared with a predefined dot pattern. A data signal for forming a dot on a line and a data signal for forming a dot on an additional raster line closer to the basic raster line from the center between two adjacent basic raster lines are generated and generated. A logic operation circuit that outputs each data signal as an actual print data signal by receiving the additional line signal, and is driven for a drive time set for each line by receiving the actual print data signal and the print drive signal. A print head for performing exposure.

The driving time is determined separately for the basic raster line and the additional raster line, independently of the time for forming dots on the basic raster line and the time for forming dots on the additional raster line. Is set.

In this case, the video data signal stored in the N-line buffer is received for a plurality of dots for each line, and the raster data in the dot area is compared with a predefined dot pattern. . Then, in accordance with the comparison result, a data signal for forming a dot on the basic raster line and a dot between the two adjacent basic raster lines are formed on an additional raster line closer to the basic raster line than the center. Are generated, and the generated data signals are output as actual print data signals.

Also, the drive time for forming dots on the basic raster line and the drive time for forming dots on the additional raster line set between two adjacent basic raster lines are independent of each other. It is set for each line and additional raster line.

[0020]

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 of the present invention, FIG. 8 is a block diagram of a print data operation logic circuit of the non-impact printer of the present invention, and FIG. 9 is an enlarged view of an N-line buffer.

In FIG. 1, 1 is a microprocessor,
A control unit including a ROM, a RAM, an input / output port, a timer, and the like. The control unit is provided inside a printing unit of the printer. Perform printing operation. When a print instruction is received by the control signal 10, the control unit 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. For example, the heater 22a is turned on by the signal 21 to heat the fixing device 22 to a usable temperature. Next, the developing / transfer process motor (PM) 3 is rotated via the driver 2, and at the same time, the charge high voltage power supply 25
Is turned on 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 a printing mechanism inside the printer.

The control unit 1 transmits a timing signal 12 (including a line timing signal and a basic raster timing signal) to the upper controller when the paper reaches the printable point, and receives the video signal 11. . The received video signal 11 is sent to the print data operation logic circuit 16 via the control unit 1. Reference numeral 20 denotes a mode switching signal, which switches the operation formula in the print data operation logic circuit 16 in accordance with each mode.

Next, the print data operation logic circuit 16 will be described with reference to FIG. When a line timing signal (ISYNC) 12 b generated for each print line is input to the timing circuit 34 by the control unit 1, the timing circuit 34 sends a selection signal to the selection circuit 33. Upon receiving the selection signal, the selection circuit 33 selects a line in the N-line buffer 31 and sequentially stores the video data signal 14 input from the control unit 1 in the selected line. The stored address is created by being counted by the counter 30 by the video clock signal 12a input from the control unit 1.

Here, the point in time when the video data signal 14 input from the control unit 1 is stored in the N-line buffer 31 will be described. As shown in FIG. 9, N line buffers 1 to N are provided in the N line buffer 31, and the line buffers 2 to N have N-addresses assigned to addresses addressed by the counter 30. The video data signal 14 up to one line before is stored.

Here, the logical operation circuit 35 receives continuous N × N dot raster data of N dots of N lines from the N line buffer 31 and is defined in the logical operation circuit 35 in advance. There is means for comparing whether or not the pattern matches the dot pattern. FIG. 10 is a diagram illustrating an example of a dot pattern defined in the logical operation circuit.

In this case, the value of N in the N line buffer 31 is "5", and continuous raster data of 5.times.5 dots is shown. (A) shows eight stages of fatning, (b) shows five stages of Bayer, and (c) shows six stages of Bayer. The logical operation circuit 35 determines whether or not to convert a dot corresponding to the center of an area of N × N continuous raster data. That is, the raster data is compared with the defined dot pattern, and if they do not match, it is determined that the raster data of N × N dots does not form a part of the gradation expression, and the video data transferred from the control unit 1 is determined. The data signal 14 is transferred as it is to the print head 19 as the actual print data signal 37.

If they match, it is determined that the raster data of N × N dots constitutes a part of the gradation expression, and the video data signal 14 input from the control unit 1 is converted. Is transferred to the print head 19 as the actual print data signal 37. In this case, the video data signal 14 before conversion has a structure indicating whether or not dots are formed on a basic raster line set corresponding to the resolution of the apparatus, whereas the data after conversion has the basic data. A structure indicating whether dots on a raster line are deleted and dots are formed on x additional raster lines added between two adjacent basic raster lines. When printing dots on x additional raster lines, the drive energy (drive time) is set in advance to a value that optimizes the gradation expression by the dots placed on the additional raster lines.

FIG. 11 is a comparison diagram of the LED light emission energy intensity between the normal driving and the gradation expression optimizing driving. In the figure, the solid line indicates the LED emission energy intensity during normal driving, and the broken line indicates the LED emission energy intensity during gradation expression optimization driving. These LED emission energy intensities are printed on dots on each additional raster line. The driving time is adjusted by setting the driving time corresponding to the distance between adjacent dots. If the driving time is set to be long, the surface of the photosensitive drum is exposed for a long time, and the amount of charge that escapes from the surface of the photosensitive drum increases in accordance with the exposure amount. Then, the amount of toner adhering thereto increases and the diameter of the dot increases.

When the LED emission energy intensity is set so as to optimize the gradation expression as indicated by the broken line, the overlap area of adjacent dots is reduced, and the print density of the portion where dots are concentrated is reduced. Can be suppressed. FIG. 12 is a data conversion state diagram in the logical operation circuit,
FIG. 13 is another data conversion state diagram in the logical operation circuit.
Reference numeral 4 denotes an operation time chart of the printer control circuit.

In the case of FIG. 12, since the raster data of N × N dots coincides with one of the dot patterns defined in the logical operation circuit 35, the dot C on the basic raster line located at the center is an additional raster line. It is converted to the dot C ₁ and dot C ₂ on the line (the number of additional raster lines are as "2".). In the case of FIG.
Since the raster data of N × N dots does not match the defined dot pattern, the dot D on the basic raster line located at the center is transferred to the print head 19 without conversion, and the additional raster line is added. No dots are formed on top.

In FIG. 14, the control unit 1 is provided for each line.
Is transmitted one line at a time in the same manner as in a conventional non-impact printer. On the other hand, the actual print data signal 37 transferred to the print head 19 includes data on the basic raster line and the added x additional raster lines, and is latched, driven, and printed on paper. The driving energy (driving time) is set independently when driving data on the basic raster line and when driving data on the added x raster lines, and the control unit 1 has a circuit for that. .
If the drive time is set to be long, the surface of the photosensitive drum is exposed for a long time, and the amount of charge that escapes from the surface of the photosensitive drum increases in accordance with the exposure amount. Then, the amount of toner adhering thereto increases and the diameter of the dot increases.

Next, a description will be given of an operation in a case where high-duty printing in which the number of dots in a print screen is very large, such as when printing a blank character, is performed. In this case, the logical operation circuit 35 receives N × N dots of continuous raster data for N dots of N lines from the N line buffer 31 and matches the dot pattern defined in the logical operation circuit 35 in advance. It has means for comparing whether or not. Then, data located at the center of the area is created by a logical operation. While the video data signal 14 input from the control unit 1 has a structure indicating whether or not to form dots on a basic raster line determined according to the resolution of the device, the video data signal 14 is generated by the logical operation circuit 35. Data has a structure of whether or not to form dots on the basic raster line and whether or not to form dots on x additional raster lines added between the basic raster lines. . The data created by such an operation is sent to the print head 19 as an actual print data signal 37.

FIG. 15 is a data conversion state diagram in the logic operation circuit during high duty printing, FIG. 16 is another data conversion state diagram in the logic operation circuit during high duty printing, and FIG. 17 is a logic diagram during high duty printing. FIG. 11 is a diagram illustrating still another data conversion state in the arithmetic circuit. In the figure, N
The value of N of the line buffer 31 is set to "5". Each dot pattern illustrates a dot pattern at the time of high duty printing, such as a dot pattern having an independent unprinted portion, a dot pattern having a blank line, a dot pattern having a blank character, and the like. The dot pattern at the time of printing is defined in the logical operation circuit 35 in advance.

In the case of FIG. 15, in the raster data of N × N dots, since the unprinted portion is located adjacent to the dot E located at the center, the dot E on the basic raster line is deleted and the additional raster line is deleted. to add a dot E ₁ above.
The same processing is performed for the dots F to H, the dots F to H on the basic raster line are deleted, and the dots F _{1 to} H ₁ are added on the additional raster lines.

In the case of FIG. 16, an unprinted portion is detected by the N-line buffer 31 as a straight line. The dots E to N on the basic raster line are deleted as in the case of FIG.
Dot E ₁ ~N ₁ is added to on an additional raster line.
In the case of FIG. 17, the dot E on the basic raster line is similarly
To M are deleted and dots E _{1 to} M are added on the additional raster line.
₁ is added.

Here, the driving energy for printing the dots on the additional raster line can be set independently of the driving energy for printing the dots on the basic raster line as described above. FIG. 18 is a comparison diagram of LED light emission energy intensity during normal driving and white spot printing optimization driving.

In the drawing, the solid line indicates the LED light emission energy intensity during normal driving, and the broken line indicates L during the blank printing optimization driving.
The ED emission energy intensity is shown. As shown in the figure,
The driving energy is set in advance so that the gap between the unprinted portions is equal to the grid length of the basic raster line (the resolution pitch of the device). By performing such processing, the remaining amount of the unprinted portion during high-duty printing becomes equal to the resolution pitch and becomes clear.

In the above embodiment, the case where only the dots adjacent to the unprinted portion are converted is described. However, the conversion is also performed for the dots in the printed portion, and the driving time of the dots on the basic raster line and the conversion on the additional raster line are changed. May be controlled so as to obtain a print dot shape during normal driving. FIG. 19 is a data conversion state diagram when the drive time of the dots on the basic raster line is changed at the time of high duty printing. FIG. 20 is another diagram when the drive time of the dots on the basic raster line is changed at the time of high duty printing. FIG. 21 is still another data conversion state diagram when the drive time of the dots on the basic raster line is changed during high duty printing.

As shown in the figure, in this embodiment, the calculation is performed not only on the dots adjacent to the unprinted portion but also on the dots in the printed portion. That is, for the dots adjacent to the unprinted portion, the dots on the basic raster line are deleted and the converted dots are added on the additional raster lines, and for the dots on the printed portion, the converted dots are added on the additional raster lines. In addition to adding a dot, the converted dot is left on the basic raster line.

The actual print data signal 37 having the above configuration is sent to the print head 19, and is emitted from the exposure device to irradiate the photosensitive drum charged to a negative potential to increase the potential on the surface of the photosensitive drum. The image is formed as a latent image. Then, the toner for image formation charged to the negative potential is attracted to each dot by an electric attraction force to form a toner image.

Thereafter, the toner image is sent to a transfer section, and a transfer signal 24 turns on a high-voltage power supply for transfer 26 having a positive potential, so that a transfer unit 28 transfers the toner image to a gap between the photosensitive drum and the transfer unit 28. Is transferred onto the paper passing through.
The sheet having the transferred image is transported in contact with the fixing device 22 having the heater 22a therein, and is fixed on the sheet by the heat of the fixing device 22. The sheet having the fixed image is further conveyed and discharged from the printer through the sheet discharge sensor 7 from the printing mechanism of the printer.

The control unit 1 controls the transfer unit 28 in response to the detection of the sheet size sensor 9 and the sheet inlet sensor 6.
The voltage from the transfer high-voltage power supply 26 is applied to the transfer device 28 only during the passage through the transfer device. When the printing is completed and the paper passes through the paper outlet sensor 7, the application of the charging high voltage power supply 25 to the developing device 27 is completed, and the
The rotation of the transfer process motor 3 is stopped.

The present invention is not limited to the above embodiment, but can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the present invention.

[0045]

As described above in detail, according to the present invention, in a non-impact printer, N video data signals of a plurality of N lines are stored for each line.
A line buffer, means for generating a reference line timing signal, means for generating an additional line signal between the timings of the reference line timing signal to divide the two basic raster lines into a plurality, and And a selection circuit for selectively outputting a video data signal to the N-line buffer in response to the line timing signal. Further, the video data signal stored in the N-line buffer is received for a plurality of dots for each line, and the raster data of the dot area is compared with a predefined dot pattern, and the result is made to correspond to the comparison result. A data signal for forming dots on the basic raster line and a data signal for forming dots on an additional raster line closer to the basic raster line from the center between two adjacent basic raster lines. A logical operation circuit that outputs each of the generated data signals as an actual print data signal by receiving the additional line signal, and a drive time set for each line by receiving the actual print data signal and the print drive signal And a print head that is driven only to perform exposure.

The driving time is determined separately for the basic raster line and the additional raster line, independently of the time for forming dots on the basic raster line and the time for forming dots on the additional raster line. Is set. In this case, between the basic raster line and two adjacent basic raster lines, dots are formed on an additional raster line closer to the basic raster line from the center, so that gradation expression is performed, printing of characters, lines, etc. Or the like, an optimal driving energy can be set. Then, the print head is driven for a drive time set for each of the basic raster line and the additional raster line.
Therefore, print quality can be improved.

Further, the portion where the unprinted portion and the printed portion contact each other during high-duty printing can be sharpened, so that the print quality can be improved. Then, in the normal print mode and the high duty print mode, the print result can be optimized. Further, since a data signal is generated on the printer side for printing,
The host controller is not affected.

[Brief description of the drawings]

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

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

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

FIG. 4 is a diagram illustrating print data during normal printing in a conventional non-impact printer.

FIG. 5 is a diagram illustrating a printing result at the time of normal printing in a conventional non-impact printer.

FIG. 6 is a diagram illustrating print data during high-duty printing in a conventional non-impact printer.

FIG. 7 is a diagram illustrating a printing result at the time of high duty printing in a conventional non-impact printer.

FIG. 8 is a block diagram of a print data operation logic circuit of the non-impact printer of the present invention.

FIG. 9 is an enlarged view of an N-line buffer.

FIG. 10 is a diagram illustrating an example of a dot pattern defined in a logical operation circuit.

FIG. 11 shows an LED at the time of normal driving and at the time of driving for gradation expression optimization
It is a luminescence energy intensity comparison figure.

FIG. 12 is a data conversion state diagram in a logical operation circuit.

FIG. 13 is another data conversion state diagram in the logical operation circuit.

FIG. 14 is an operation time chart of the printer unit control circuit.

FIG. 15 is a diagram illustrating a data conversion state in a logical operation circuit during high duty printing.

FIG. 16 is another data conversion state diagram in the logical operation circuit at the time of high duty printing.

FIG. 17 is still another data conversion state diagram in the logic operation circuit at the time of high duty printing.

FIG. 18 shows LE during normal driving and white spot printing optimized driving.
It is a D light emission energy intensity comparison figure.

FIG. 19 is a data conversion state diagram when changing the drive time of dots on a basic raster line during high duty printing.

FIG. 20 is another data conversion state diagram when changing the drive time of dots on a basic raster line during high duty printing.

FIG. 21 is a diagram illustrating still another data conversion state when the drive time of the dots on the basic raster line is changed during high duty printing.

[Explanation of symbols]

 Reference Signs List 1 control unit 12a video clock signal 12b line timing signal 13 print drive signal 14 video data signal 16 print data operation logic circuit 19 print head 31 N line buffer 33 selection circuit 35 logic operation circuit 37 actual print data signal

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Okada 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Inventor Kazuhiko Nagaoka 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Inventor Shinichi Katakura 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References JP-A-60-165864 (JP, A) 60-146061 (JP, A) JP-A-2-59362 (JP, A) JP-A-2-60768 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2 / 52 B41J 2/44 B41J 2/45 B41J 2/455

Claims (1)

(57) [Claims] 1. An N-line buffer for storing video data signals of a plurality of N lines for each line; (b) means for generating a reference line timing signal; and (c) two basic rasters. To divide between lines into multiple
, The means for generating the additional line signal between the timing of the line timing signals of the reference, (d) receiving the line timing signal of the reference, selection circuit for selectively outputting the video data signal to said N-line buffer And (e) receiving the video data signal stored in the N-line buffer for a plurality of dots for each line, comparing the raster data in the dot area with a predefined dot pattern, and comparing the result. in correspondence with the data signal for forming a dot on the basic Rasutarai down, and adjacent Oite between two basic raster line, the center
Each data signal of data signals generated respectively, that are generated for forming dots on the additional Rasutarai down close to the basic raster line, Rukoto receiving the additional line signal
A logical operation circuit for outputting the actual print data signal by the, and (f) printing head receiving the actual printing data signal and the print drive signal is driven by the set driving time for each line performs the exposure and having, (g) the operating time, and for forming a dot on the basic raster line, and so are independent for forming dots on the additional raster line, the basic raster lines and additional raster line by line Non-impact printer characterized by being set to.