JP3209517B2 - Printing method and printing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printing method and a printing apparatus, and more particularly to a printing method and a printing apparatus for saving toner and ink.

[0002]

2. Description of the Related Art In a printing apparatus such as a printer apparatus, a facsimile apparatus, and a digital copying apparatus, an electrophotographic system is often used. In a laser printer employing this electrophotographic method, an electrostatic latent image is formed on a photosensitive drum while laser light emitted from a semiconductor laser light emitter is scanned by a polygon mirror, and toner is attached to the electrostatic latent image. Then, the image is transferred to recording paper and printed.

In an LED printer, instead of a semiconductor laser beam, a print head having an LED irradiates a dot position corresponding to an image to be printed with light to form an electrostatic latent image on a photosensitive drum. Print on.

[0004] On the other hand, in an ink jet printing apparatus, printing is performed by ejecting ink from nozzles of a print head to adhere to recording paper in accordance with an image to be printed.

[0005] In such an electrophotographic or ink jet printing apparatus, toner and ink are usually supplied from a toner cartridge or an ink cartridge.
The consumption of toner and ink directly affects the running cost of the printing apparatus.

Therefore, conventionally, for the purpose of reducing running costs, a printing apparatus is provided with a resource saving mode function for saving the amount of toner and the like, and a thinning process for reducing black pixels in an image to be printed is performed. It saves toner and ink usage.

[0007]

However, the conventional thinning process has the following disadvantages. Since only pixels between black pixels are thinned, the resolution of characters and images is reduced. That is, when the thinning processing is applied to a printing apparatus having a low resolution, thin lines are usually formed with a width of one dot or two dots. Therefore, in a simple thinning processing, the thin lines become discontinuous or become unclear. I do. Also,
Since the image information itself is lost due to the thinning process, characters, thin lines, and images are blurred or the resolution is reduced.

In order to compensate for such a drawback, at the time of black pixel thinning processing, black pixels forming an edge portion of an image are detected by software processing, and the print data is processed so as not to be subjected to thinning. Is corrected, whereby the outline of the character or the line drawing is maintained, and the resolution of the character or the line drawing is improved.

However, in the software processing method, if the resolution is set to double for performing high-resolution printing, the amount of print data to be handled quadruples, and the amount of print data increases suddenly. I need it. Further, in high-speed printing, for example, if the printing time is set to half, software processing twice or more times is required. Therefore, a high-speed-capable CPU and an arithmetic processing unit are required, which makes the printing apparatus expensive. There were drawbacks.

[0010]

The present invention has the following arrangement to solve the above-mentioned problems. <Configuration 1> The present invention supplies the print data to the print head, a plurality of indicia
A printing method for printing by printing dots, resource saving mode
Non-thinning printing of multiple print dots per line
It is characterized in that dots are thinned out so as to be continuous .

<Structure 2> Another invention is to supply print data to a print head,
A printing method for printing using print dots,
At the time of loading, printing dots are thinned out for each line, and control is performed to increase the printing density .

<Structure 3> In the above two inventions, the print head to which the print data is supplied includes a light emitting element for exposing a photosensitive portion, and the light emitting element is adapted to cope with the deterioration of the photosensitive portion over time.
And controlling the print head to increase the exposure energy .

<Structure 4> The printing apparatus of the present invention converts print data into print dots when supplied.
A printing apparatus comprising a print head to more printing, saving
In resource mode, multiple print dots per line
It is characterized in that it includes a thinning circuit for thinning out so that thinned printing dots are continuous .

<Structure 5> Another printing apparatus according to the present invention, when print data is supplied,
Printer with a print head that prints
And thin out printing dots for each line in resource saving mode
It is characterized by including a thinning circuit and a density control circuit for controlling to increase the print density in the resource saving mode .

<Structure 6> In the apparatus of the present invention, the print head to which the print data is supplied includes a light emitting element for exposing a photosensitive portion, and a deterioration detecting means for detecting the deterioration of the photosensitive portion with time. A storage unit for storing an exposure energy set value corresponding to the deterioration of the photosensitive unit over time; and a light emitting unit for controlling a light emitting element of the print head based on the exposure energy set value.
And an element control circuit.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In this embodiment, an LED printer section is provided as a printing apparatus, a scanner section is provided as a reading apparatus, and further, transmission / reception and copying of image information of a document are performed. A multi-function device that has a facsimile device and is connected to a personal computer (PC) via a connection cable to be used as a printing device or reading device of the PC, or to be connected to a LAN and used as a terminal of the LAN. Have been.

FIG. 2 is a block diagram of a multi-function device to which the present invention is applied. This multi-function device 1 includes a CPU 2 and an SR
RAM3 composed of AM, DRAM, etc., and FLASH
A memory 4, an image processing LSI 5, a print control circuit and an I / O
A dedicated ASIC (application-specific integrated circuit) 6 incorporating an O-circuit and the like, an operation panel 7 for an operator to operate, and an NCU (communication control unit) 8 connected to a telephone line
, A modem 9 and a LAN connection I / O connected to the LAN.
An F circuit 10 and a PC connection general-purpose I / F circuit 11 for connecting to a PC (personal computer) are provided.

The multifunctional device 1 further rotates a scanner unit 13 including a mechanical unit such as an image sensor 12 and a scanner motor (not shown), and rotates an LED head 14, a drum unit (not shown), a fixing device, and a photosensitive drum. The printer unit 16 includes a print engine 15 having a motor to be driven, a paper feed unit for feeding recording paper, and the like. Incidentally, 17
Is connected to the NCU 8 by handset.

The CPU 2 has, via a common bus including a data bus, a RAM 3, a FLASH memory 4 in which programs and various data are held, an image processing LSI 5 for processing image data read from the image sensor 12,
The ASIC 6 is connected. The common bus has an operation panel 7, an NCU 8, a modem 9, and a LAN connection I / F.
A circuit 10 and a PC connection general-purpose I / F circuit 11 are connected.

In the multi-function device 1 having the above configuration, the facsimile receiving operation will be described.
The analog data is sent to the modem 9 via 8. The modem 9 converts analog data into digital data.
The received image data converted to digital data is stored in RAM
3 is temporarily stored. Since such received image data is subjected to compression coating (MH / MR coating), it is decoded via the CPU 2 and is again stored in the RAM.
The image data is developed and stored in the image data 3. ASIC6
Supplies the developed image data to the image processing LSI 5 to perform print image processing while controlling the print engine 15, and supplies the image data to the LED head 14 as print data.

In the print engine 15, the LED head 14
Drives to expose the photosensitive drum to form an electrostatic latent image. Then, toner is attached to the electrostatic latent image and transferred to a recording sheet. Printing is performed on the recording paper by thermally fixing the transferred toner on the recording paper with a fixing device.
The CPU 2 accesses the above devices while reading the program in the flash memory 4 and performs the above control.

Next, in a copying operation, the original document sucked into the scanner unit 13 is read by the image sensor 12 as analog data. This analog data is A / D
The data is converted into multi-value digital data by a converter and sent to the image processing LSI 5.

The image processing LSI 5 shapes the image data by performing shading correction, edge enhancement processing, and the like, further performs image processing such as binarization processing and error diffusion processing on the multi-valued digital data, and temporarily stores the multi-valued digital data in the RAM 3. To be stored.
The image data stored in the RAM 3 is developed by the ASIC 6 in the same manner as described above, sent to the LED head 14 as print data, and printed on the recording paper as described above.

Further, in the operation at the time of a print command from the PC,
First, from the PC 18, compression or P
The print data converted into the CL language is sent. This data is transmitted to the RA via the PC connection general-purpose I / F circuit 11.
It is temporarily stored in M3. The compressed data or PCL description data temporarily stored in the RAM 3 is decompressed or expanded into bitmap data and stored again in the RAM 3 as image data. The image data stored in the RAM 3 is stored in the ASIC as described above.
6 is supplied as control data of the print engine 15 and print data to the LED head 14, and the received image from the PC 18 is printed.

When print data is sent from the LAN,
The processing is performed in the same manner as the print data from the PC 18. That is,
Print data is sent from the LAN with an IP address specified. The print data is received via the LAN connection I / F circuit 10 and temporarily stored in the RAM 3. Hereinafter, it is the same as the print data processing from the PC 18.

In the facsimile transmission operation, when the scanner unit 13 inhales the original, the image sensor 12 reads the original, and the analog data read by the A / D converter is converted into digital data and sent to the image processing LSI 5. The image processing LSI 5 shapes the image data by performing shading correction, emphasizing processing on digital data, and the like, further performs image processing such as binarization processing and error diffusion processing, and temporarily stores the image data in the RAM 3.

With respect to this temporarily stored data,
MH-MR compression (coding) for FAX
And temporarily stored in the RAM 3 again. Then, the CPU 2 makes a call to the telephone line via the NCU 8, and when the line is connected, converts the transmission data coated via the modem 9 into analog data and sends it to the telephone line.

FIG. 1 shows a data thinning circuit according to a first embodiment of the present invention. The data thinning circuit 20 includes a data mask circuit 21 and a toner save set register (CPU
An I / F circuit 22 is provided in the ASIC 6.

As shown in FIG. 1, the data mask circuit 21 has a flip-flop 217, and OR gates 215 and 216 having one input connected to the Q output and the inverted Q output of the flip-flop 217. An inverter 218 is connected to the other inputs of the OR gates 215 and 216. One input of AND gates 214 and 212 and one input of AND gates 213 and 211 are connected to outputs of the OR gates 215 and 216, respectively. These AND gates 211, 212, 213, 21
4 are connected to data lines 30a, 30b, 30
c and 30d are respectively connected.

The inverter 218 and the reset terminal of the flip-flop 217 are connected to the toner save set register 22.

FIG. 3 shows a driving circuit inside the LED head 14. The drive circuit 40 is connected to the AND gate 21
Shift register 4 connected to the outputs 1-21-2
1, 42, 43, and 44, and a latch circuit 45 connected to the output side of these shift registers.
A large number of AND gates 46 are connected to the output side of the latch circuit 45, and an LED 47 as a light emitting element is connected to the output side of these AND gates 46. Each AND gate 46 is divided into four groups corresponding to the respective shift registers 41 to 44, and the strobe signals 1 to 4 are input to the other inputs.

The image data stored in the RAM 3 is sent to the ASIC 6 for printing, and
The data is stored in a line buffer (not shown) in C6 in units of one line. The stored one-line data is read from the line buffer after the one-line synchronization signal is generated, and a margin for the left and right margins is added. Alternatively, white data is obtained by masking the data. The data to which the left and right margins have been added is converted into 4-bit data to match the data line width of the LED head 14, and distributed to the data lines 30a to 30d in FIG. That is, RAM
3 is subjected to print image processing via the image processing LSI 5, and then to the data lines 30a to 30a.
This is print data for every four pixels sent to d. The print data is thinned out by the data thinning circuit 20 of this specific example as described later.

The output signal b from the toner save set register 22 is an initialization signal at the start of the operation of the data mask circuit 21, and switches from "L" to "H". When the toner save set register 22 is set so that the signal a is set to “H”, the data thinning circuit 20 becomes operable. The LSYNC signal input to the flip-flop 217 is a one-line synchronization signal, and is a pulse signal generated each time the line advances in the sub-scanning direction.

FIG. 4 is an operation timing chart of the data thinning circuit 20. Toner save set register (C
The signal a of the PUI / F circuit is set to “H”. In this state, when the LSYNC signal of the first line enters the flip-flop 217, the Q output of the flip-flop 217 becomes “H” and the inverted Q output becomes “L”. On the other hand, when the signal a is “H”, the output of the inverter 218 becomes “L”, so that one input of the OR gates 215 and 216 is “L”.
Becomes Therefore, the output c of the OR gate 215 is Q inverted.
The output "L" appears, and the Q output "H" appears at the output d of the OR gate 216.

As described above, in the first line, the output of the OR gate 216 is “H”, and the AND gates 211 and 213
Becomes "H", the AND gate 21
The values of the print data DATA1 and DATA3 appear as they are in the outputs 1 and 213.

In the first line, the OR gate 21
5 is "L", the AND gates 212, 21
4 becomes "L", so that the AND gate 21
2, 214 output is fixed to "L" output, and print data
DATA2 and DATA4 are not output. That is, since the print data DATA2 and DATA4 of the even dots are masked and supplied to the LED head 14, the even dots are not printed.

Therefore, since the toner for even-numbered dots is not used for printing, the toner is saved (saved) by that much.

When the next line (the second line in FIG. 4) is reached and the LSYNC signal is input, the output of the flip-flop 217 is inverted. That is, since the output c of the OR gate 215 becomes “H” and the inputs of the AND gates 212 and 214 become “H”, the print data DATA2 and DATA4 are output from the AND gates 212 and 214. On the other hand, since the output d of the OR gate 216 is “L”, the AND gate 2
Outputs 11 and 213 are fixed at "L" output, and print data DATA1 and DATA3 are not output. That is, since the odd dot print data DATA1 and DATA3 are masked and supplied to the LED head 14, the odd dots are not printed.

FIG. 5 is a timing chart of data transfer to the LED head 14. HDDATA1 to HDDATA4 are print data after mask processing on the LED head. HDCLK is L
This is a clock signal for transferring data to the ED head 14. The falling edge of this clock signal causes the shift register 4
Print data HDDATA1 to HDDATA4 after mask processing
Are sequentially transferred.

When the transfer of the print data for one line is completed, the ASIC 6 generates an HDLD signal, and the ASIC 6 stores the shift register 41 in the latch circuit 45 corresponding to one LED line.
To 44 to load the sequentially transferred print data. ST
RB1 to RB4 are strobe signals for causing the LED 47 to emit light, and the LED 47 corresponding to the value of the latch circuit 45 of 1 ("H") emits light. Hi of these strobe signals
The light emission time (emission energy) of each LED 47 is set in a time width of gh.

The print data HDDATA1 is sequentially packed into the shift register 41 from the head as shown in FIG. The other print data HDDATA2, 3 and 4 are similarly sequentially packed into the shift registers 42, 43 and 44. When the transfer of one line of print data is completed, an HDLD signal is generated, and the data in the shift register is latched by the latch circuit 45.
To load. Strobe signal when load value is "H"
When the STRBs 1, 2, 3, and 4 are supplied, the LED 47 emits light, an electrostatic latent image is formed on a photosensitive drum (not shown), and the image is printed by the print engine 15. In this specific example, the strobe signal for causing the LED 47 to emit light is such that the LED 47 is divided into four blocks and emits light at different times.

As described above, by dividing the number of data lines into four lines and masking the plurality of data lines by dividing them into odd lines and even lines, it is very easy to thin out print data in the main scanning direction. Can be done. Also, in the sub-scanning direction, the data lines are switched such that the LSYNC signal indicating the period in the sub-scanning direction is detected and the odd lines and the even lines are switched to alternately mask each line. The print data thinning process can be easily realized by a circuit having a very simple configuration, and printing with less toner can be performed.

Further, according to the first embodiment, since there is no intervention of thinning-out processing by software, there is no burden on the CPU 2 and the hardware is simple. By using four data lines, there is an effect that print data can be quadrupled at the current clock speed. In addition, there is an effect that the resolution can be increased four times as long as the one-line cycle is the same.

<Specific Example 2> The circuit configuration of specific example 1 is LE
This is a great effect when the resolution of the D head and the resolution of the image drum have been improved and the reproducibility of isolated dots without adjacent dots has been sufficiently obtained.
There is a great effect on a printing apparatus of about i. By the way, LE
When the resolution of the D head is increased to 1200 dpi or 2400 dpi, the irradiation area per dot becomes smaller in accordance with the resolution, and the exposure energy also becomes smaller, so that a sufficiently high resolution reproduction as an ID (image drum) is reproduced. What is required is. However, the high resolution of the LED head is advanced, and the high resolution reproducibility of the ID is often developed later.

On the other hand, when printing a normal document, if the resolution is sufficiently high, even if the reproducibility of one dot is low, an oblique line or a rounded curve can be drawn smoothly because of the high resolution. And high quality images can be obtained.

However, when printing is performed in a staggered pattern as in Example 1 in order to suppress toner consumption, each dot has little connection with other dots, and it can be considered that most of the dots are isolated dots. If the reproducibility of the image is deteriorated or varies, there is a possibility that a thin line, an omission or blurring of an image may occur at the time of toner saving. Example 2 solves this problem.

This specific example is characterized in that a density control circuit 50 is further provided in the ASIC 6 as shown in FIG. In FIG. 6, reference numeral 51 denotes a register for storing a strobe value in a normal mode (not toner save).
A register 52 stores a strobe value in the toner save mode. Reference numeral 53 denotes a selector circuit, which selects and switches either the strobe value in the normal mode or the strobe value in the toner save mode according to the value of the toner save ON / OFF signal, and supplies the selected strobe value to the LED strobe generation circuit 54.

The strobe value of the toner save mode is set to a value larger than the strobe value of the normal mode (a value that increases the amount of light). By giving a value that increases the light amount, the exposure energy is increased, and the toner is stably attached to the photosensitive drum. Also, by setting the exposure energy to a value larger than the normal setting,
It is possible to form a stable electrostatic latent image by absorbing variations in the exposure amount of the photosensitive drum.

Next, the operation of the density control circuit 50 will be described. At the time of toner save off (normal mode), the toner save ON / OFF signal is OFF.
The normal mode strobe value of 1 is selected by the selector circuit 53 and supplied to the LED strobe generation circuit 54. In the LED strobe generating circuit 54, the strobe signals STRB1 to STRB4 are generated with a normal strobe width, and the LED 47 emits light, similarly to the timing chart of FIG. When the toner save is on, the CPU 2 turns on the toner save ON / OFF signal, so that the toner save mode strobe value of the register 52 is selected by the selector circuit 53 and supplied to the LED strobe generation circuit 54.

In the LED strobe generating circuit 54, FIG.
As shown in (5), the strobe signals STRB1 to STRB4 having a longer strobe width are sequentially generated to increase the light emission amount of the LED 47. As described above, by increasing the light amount of the LED 47 and increasing the exposure energy to be larger than the normal setting, a variation in the exposure amount of the photosensitive drum with respect to a single dot is absorbed to form a stable electrostatic latent image. It is possible to Further, as the amount of light increases, the exposure energy increases, so that the toner stably adheres to the photosensitive drum, so that the reproducibility of individual dots during toner saving increases, and thin lines are not lost or blurred. Thus, high-quality images can be printed while toner is saved. In other words, when printing in the toner save mode, the density of black solid areas is lower than that of normal printing, but fine lines can be printed with print quality comparable to that of normal printing because of sufficient reproducibility. It is.

As described in detail above, the reproducibility of one dot can be improved by increasing the light emission amount of the LED in the toner save mode. Therefore, even in the toner save mode in which isolated dots are likely to be generated, it is possible to prevent the toner attached to the isolated dots from becoming unstable, and it is possible to prevent the print from being blurred and the image from being deteriorated. . Furthermore, even in the toner save mode, the black solid portion is slightly lighter than the normal image, but the reproducibility of fine lines and the like can be printed at almost the same high quality as the normal printing.

<Specific Example 3> The surface of the photoreceptor has been subjected to a photosensitive coating process for exposing light, and the layer pressure is as thin as about 10 microns. This coating surface is normally in contact with a charge roller, an LED head, a developing roller, a transfer roller, and a cleaning roller.

Therefore, the photosensitive portion gradually wears with the number of printed sheets. When the photosensitive portion is worn, the energy variation for exposing the photosensitive portion increases, or the amount of light required for exposure increases. For this reason, since the reproducibility of one dot is reduced, the adhesion of the toner corresponding to a thin line or a single dot at the time of toner saving becomes unstable, and there is a problem that the image is easily blurred. The third embodiment solves the problem that the reproducibility of one dot is reduced due to a change over time.

In the third embodiment, the density control circuit shown in FIG. 6 is improved, and a drum rotation detector 63 shown in FIG. 9 is provided. FIG. 8 shows an improved density control circuit 60,
A register 51 stores a strobe value in the normal mode, and a register 52 stores a strobe value in the toner save mode. Reference numeral 53 denotes a selector circuit which switches between a strobe value in the normal mode and a strobe value in the toner save mode according to the value of the toner save ON / OFF signal, and an LED strobe generation circuit 54.
Supply to

In the third embodiment, a toner save strobe setting register 61 is added so that the CPU 2 (see FIG. 2) can freely set the toner save strobe setting value in accordance with the rotational life of the drum. The register 61 is set so that the strobe value in the toner save mode gradually increases (a value at which the light amount increases) in accordance with the life of the drum. Reference numeral 62 denotes a normal strobe setting register for setting a normal mode strobe setting value.

As shown in FIG. 9, the drum rotation detecting section 63 has a drum motor pulse counting section 64, a drum rotation counting section 65, and a drum rotation number register 66. The drum motor pulse counting section 64 counts the number of pulses for rotating the drum motor. When counting the number of motor pulses corresponding to one rotation of the drum, the drum rotation counting section 65 increments the count value of the drum rotation number register 66 by one.

FIG. 10 is a flowchart for explaining the operation of the third embodiment. First, a print start command (step S
Upon receiving 1), the CPU 2 determines whether or not the mode is the toner save mode (step S2). That is, a flag setting unit for indicating the toner save mode is provided, and if the mode is not the toner save mode, the strobe value in the normal mode is selected, and normal printing after step S3 is performed (step S3).
9). If it is the toner save mode, the process proceeds to step S4, where the CPU 2 reads the drum rotation count number of the register 66, and if the count value is less than 5,000, it has not reached １ ／ of the life and the photoconductor has deteriorated so much. It is determined that there is no strobe setting value, and the strobe setting value in the toner save mode (a value increased in light quantity from the normal mode: 2 ranks up in this embodiment) (step S5) And start printing.

FIG. 11 shows a strobe value setting table. For example, if the LED head of the head rank 10 in the normal mode is set in the apparatus, 002Fh is set so that the strobe width of the head rank 10 becomes 37.6 μs in the rank increase of 2 in the toner save mode.
Also, 0029h is set in the normal strobe setting register 62 so as to obtain a strobe value width of 32.8 μs indicated by the head rank 10 in the normal state.

Next, if the drum rotation count is 5,000 or more, the process proceeds to step S6, and if it is less than 10,000,
The +4 rank-up strobe value is read from the value in the strobe value setting table in FIG.
1 and 52 (step S7), and printing is started. In this specific example, the life of the drum is set to 15,000 revolutions.

Further, if the drum rotation count is 10,000 or more, a strobe value of +6 ranks is read from the strobe value setting table, and the register 61,
52 (step S8) and printing is started. still,
If the drum rotation count is 15,000 or more, a message indicating that the drum life is reached is displayed on the operation panel, and the toner strobe value is set to a strobe value of +6 ranks as in the case of 10,000 or more, and printing is started. .

As described above, the life of the photosensitive drum is
By setting the strobe value in the toner save mode to gradually increase in accordance with the life of the photosensitive drum in three stages of a middle stage and a late stage, it is possible to correct the image quality deterioration due to the temporal change of the photosensitive drum. In this specific example, the life of the photosensitive drum is divided into three stages, but it is possible to make the life finer. For example, if the light amount value is gradually changed in units of 1,000 rotations, it is possible to respond more finely to deterioration over time.

Further, in this specific example, the number of rotations of the photosensitive drum is counted to cope with the aging of the photosensitive drum. However, there is no problem even if the number of prints of the recording paper is substituted. Further, although the drum rotation counting function is implemented with a hardware configuration, the same effect can be obtained even if counting is performed by software.

As described above in detail, the number of rotations of the photosensitive drum is counted, and the light emission amount of the LED in the toner save mode is increased in accordance with the counted number. The image quality can be maintained even if there is a target deterioration. Further, when the deterioration with time is corrected, the reproducibility of each isolated dot with respect to the change with time can be improved. That is, even in a print image in the toner save mode using isolated dots that are susceptible to deterioration over time, it is possible to perform constant high-quality printing without fading the print without being affected by deterioration over time.

<Embodiment 4> In Embodiment 4, the data thinning circuit is improved so that the print data thinning position can be arbitrarily selected. This makes it possible to thin out in a zigzag manner for each dot as in the first embodiment, and it is also possible to thin out data continuously.

FIG. 12 is a configuration diagram of a data thinning circuit 70 according to the fourth embodiment. This data thinning circuit 70
It is provided in the SIC 6. Data thinning circuit 70
Are a CPU I / F circuit 71 and a line switching circuit 72
, Save dot setting circuit 73, data mask circuit 7
4

The CPU I / F circuit 71 has a toner save set register 71a, a terminal for outputting an enable signal, and a terminal for outputting a reset signal. The line switching circuit 72 has a flip-flop 441, and the inverted Q output is fed back. The save dot setting circuit 73 includes an exclusive (EX) OR gate 451,
452, 453, 454, and the output Q of the flip-flop 441 is connected to one input of each EX OR gate. The other input of these EX OR gates is connected to a toner save set register 71a.

The data mask circuit 74 includes the OR gate 43
5, 436, 437, and 438, and each output side of each EX OR gate 451 to 454 is connected to one input of each OR gate. To the other input of each of the OR gates 435 to 438, an enable terminal of the CPU I / F circuit 71 is commonly connected via an inverter 411. The data mask circuit 74 includes AND gates 431 and 4
32, 433, 434, and each AND gate 431-
The output side of each OR gate 435-438 is connected to one input of 434. And each AND gate 431
The data lines 1 to 4 are connected to the other inputs of the data lines 434 to 434, respectively.

The print data DATA1 to DATA4 are stored in the RAM 3 (FIG. 2).
Image data developed in the image processing LSI
5 is data for each pixel that is sent out after image processing, and is the same as that in the first embodiment. By writing "H" to the enable register of the CPU I / F circuit 71, the output signal i from the enable terminal becomes "H", and the OR gates 435 to 438 of the data mask circuit 74 become valid. The output signal e of the reset terminal is an initialization signal at the start of masking, and is normally set to “H” for use. L
The SYNC signal is a one-line synchronization signal, and is one in the sub-scanning direction.
This pulse signal is generated when the processing of the print data for the line is completed.

FIGS. 13 and 14 are operation timing charts of the data thinning circuit according to the fourth embodiment. CPU I / F
In the toner save set register 71a of the circuit 71, "11
When "00" is written, the u, f, g, and h outputs of the circuit 71 become "H", "H", "L", and "L", respectively. C
The i signal of the enable terminal of the PUI / F circuit 71 is set to “H”
Then, when the LSYNC signal of the first line enters the flip-flop 441 of the line switching circuit 72, the output Q of the flip-flop 441 becomes "H" at the rising edge of the waveform, and the inverted Q output becomes "L". Become. Therefore, the EX OR gate 45 of the save dot setting circuit 73
4,453,452,451 output signals p, o, n, m
Are "L", "L", "H", and "H".

On the other hand, since the output signal i of the enable terminal of the CPU I / F circuit 71 is "H", the inverter 411 is inverted to "L". Therefore, the OR gates 438, 43
7,436,435 becomes "L".
The values “L”, “L”, “H”, and “H” of the signals p, o, n, and m appear in the values of the output signals t, s, r, and q. That is, since the signals r and q become “H”, the AND gates 432 and 431 output the print data DATA1 and DATA2 of the data lines 1 and 2 as they are. On the other hand, since t, s, become “L”, the AND gate 43
The outputs of 4,433 are each held at "L". Therefore, the print data DATA3 and DATA4 of the data lines 2 and 3 are
Masked. That is, 3 + 4n and 4 + 4n dots are not printed, and 1 + 4n and 2 + 4n dots are printed normally (n is a positive number).

To process the print data of the next line,
When the LSYNC signal is input to the flip-flop 441, the Q output becomes “L”, so that the data lines 3 and 4 are selected and 3 + 4n and 4+ corresponding to the print data DATA3 and 4 are selected.
4n dots are normally printed, and the print data DATA1, DATA2
1 + 4n and 2 + 4n dots corresponding to are not printed.

FIG. 15 shows the LED head 14 (see FIG. 2).
6 is a timing chart of a signal sent to the control unit. On the Nth line, the print data DATA4 and DATA3 are thinned out.
On the other hand, in the (N + 1) th line, the print data DATA
2, DATA1 is similarly thinned out.

In the fourth embodiment, the thinning-out position is changed for each line in the sub-scanning direction. However, by setting the value of the toner save set register from the CPU 2 in units of two lines and three lines, it is possible to perform the thinning processing of two lines and three lines at the same position. In this case, when the output signal e of the reset terminal is fixed at “L”,
The Q output of the flip-flop becomes “L”. Therefore,
Output signals u, f, g, and h are set to “H”,
"H", "L", "L", and the second line
When set to “H”, “L”, “L”, the output signals n, m
And r and q become "L", and the print data DATA1, DATA2
Is drawn for two lines. The output signals u, f, g, and h are set to “L”,
If “L”, “H” and “H” are set, the print data DATA
3, DATA4 is drawn for two lines. Therefore, 2 × 2
Dot thinning can be realized. In this manner, it is possible to thin out the same position continuously in the sub-scanning direction.

As described above, when the CPU 2 performs control on a line-by-line basis, the degree of freedom in thinning out in the sub-scanning direction is increased. Also,
In this specific example, the case where the number of data lines is four has been described.
Even if the number of data lines is increased to eight lines, eight lines, and sixteen lines, the invention can be applied in exactly the same manner. Further, in the fourth embodiment, by combining with the configurations of the second and third embodiments, it is possible to control the density and to cope with aging of the photoconductor.

As described above, the print data thinning position can be arbitrarily selected. Therefore, for a print resolution of 1200 dpi or more, for example, a thinning corresponding to two dots is set, and a thinning suitable for the resolution is set. The position can be set. That is, the printing resolution is 2400 dp.
If it is set to i or the like, the exposure area of the photoconductor in dot units becomes small, and only a few toners can adhere to one dot. Therefore, the reproducibility of one dot alone becomes extremely unstable. However, in Example 4, since the dot positions to be printed can be set continuously, the exposure area can be increased, the toner can be stably attached, and the reproducibility of the image can be improved.

In each of the above examples, the LED using toner is used.
Although the head method has been described, the present invention is similarly applicable to an ink jet printing method. That is, during the ink save mode of the ink-jet system, by increasing the density and the amount of ink of the dots that are not thinned out, it is possible to suppress omission and blurring of the image while maintaining the reproducibility of the image.
It is equally possible. For example, in the case of a piezo-type ink jet printer, setting of the density and deterioration over time can be handled by controlling the voltage level applied to the piezo element, the voltage application time, and the like.

In the laser beam method, the laser beam is printed by modulating the laser beam with serial data. However, the present invention can be applied to, for example, parallel data read from a memory before being converted into the serial data. It is possible. Further, the present invention is applicable to serial data transfer by converting print data sent in parallel to serial data.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a data thinning circuit according to a specific example 1 of the present invention.

FIG. 2 is a block diagram of a multifunction device to which the present invention is applied.

FIG. 3 is a drive circuit diagram of the LED head.

FIG. 4 is an operation timing chart of the data thinning circuit of the specific example 1.

FIG. 5 is a timing chart of data transfer to the LED head according to the first embodiment.

FIG. 6 is a density control circuit diagram of a specific example 2.

FIG. 7 is a data transfer timing chart of a specific example 2.

FIG. 8 is a diagram illustrating a density control circuit according to a third embodiment.

FIG. 9 is an explanatory diagram of a drum rotation detection unit according to a third embodiment.

FIG. 10 is a flowchart illustrating an operation of a specific example 3.

FIG. 11 is an explanatory diagram of a strobe value setting table.

FIG. 12 is a configuration diagram of a data thinning circuit according to a specific example 4.

FIG. 13 is an operation timing chart (part 1) of the data thinning circuit according to the fourth embodiment.

FIG. 14 is an operation timing chart (part 2) of the data thinning circuit according to the fourth embodiment.

FIG. 15 is a timing chart of data transfer to an LED head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Multi-function device 2 CPU 3 RAM 4 FLASH memory 5 Image processing LSI 6 ASIC (application. Specific. Integrated circuit) 14 LED head 20 Data thinning circuit 21 Data mask circuit 22 Toner save set register (CPU I / F circuit) 30a -30d Data line 211-214 AND gate 215,216 OR gate 217 Flip-flop 218 Inverter

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 2/44 B41J 2/45 B41J 2/455 B41J 5/30

Claims (6)

(57) [Claims] 1. A supplying print data to the print head, a plurality
A printing method for printing with the print dots of the above. In the resource saving mode, a plurality of print dots for each line are
A printing method characterized in that thinning-out printing dots are thinned out to be continuous . 2. A method for supplying print data to a print head, comprising:
This is a printing method in which printing is performed using the printing dots of a single line.
Mark <br/> printing how to and controlling so as to increase the print density to. 3. The print head to which the print data is supplied includes a light emitting element for exposing a photosensitive section, and the light emitting element is adapted to cope with deterioration of the photosensitive section over time .
3. The printing method according to claim 1, wherein the print head is controlled to increase the exposure energy . 4. When print data is supplied , the print dots are formed.
A printing device having a print head for performing more printing, wherein a plurality of print dots for each line are
A printing apparatus, comprising: a thinning circuit for thinning out continuous thinned printing dots . 5. When print data is supplied, a print dot is formed.
A printing apparatus having a print head for performing more printing , wherein the printing dots are thinned out for each line in the resource saving mode.
And the circuit comes to the resource saving mode, printing device you; and a concentration control circuit for controlling so as to increase the print density. 6. The print head to which the print data is supplied, the print head includes a light emitting element for exposing a photosensitive portion, and a deterioration detecting means for detecting the deterioration of the photosensitive portion over time; The storage unit according to claim 4, further comprising: a storage unit configured to store an exposure energy set value corresponding to the deterioration; and a light emitting element control circuit that controls a light emitting element of the print head based on the exposure energy set value. Printing device.