JPH04197671A - Printer - Google Patents

Abstract

PURPOSE:To easily change a printing density by controlling a printing head on a unit in accordance with a printing density detected by a detection means. CONSTITUTION:A printer body 10 is provided with a power source connector 4 connected to a power source connector 32, a control signal connector 5 connected to a control signal connector 33, and a photointerrupter 6. The photointerrupter 6 for detecting a printing density of a printing head 31 is interrupted by a light interrupting member 343 on a unit case 34 when a unit 3 is disposed in position in the body 10. Namely, the light interrupting member 343 on the unit case 34 interrupts the body side of the photointerrupter 6 when the unit 3 is set in position in the printer body 10, whereby a printing density of the unit 3 is detected. In this manner, even on the user side, a printing density can be easily changed by replacing a printing head, and a high-cost printer can be effectively used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a printer using a solid-state scanning print head using an LED array, liquid crystal, PLZT, EL array, or the like.

[Prior Art] In a printer using a solid-state scanning printhead, such as an LED printhead, the printhead is generally attached to the printer body and connected to a power source via a power supply connector. , are connected to the head control unit via a control signal controller and are controlled by the control unit.

The print head has the advantage that it has no moving parts and has a long lifespan compared to a laser diode print head.

[Problem to be solved by the invention]

However, in printers using such solid-state scanning printheads, when the printing density of the printhead differs, the head size, control signal, power supply, control signal connector, etc. differ, and it is difficult to change the printing density as easily as in a laser printer. Can not.

In other words, in conventional printers of this type, the print heads of 300 dpi and 400 dpi, for example, have different lengths and are not compatible, and furthermore, they are not compatible in terms of different hend widths, different connectors, etc. Therefore, it was extremely difficult to change the printing density.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a printer using a solid-state scanning print head in which the user can easily change the print density by replacing the print head with a print head having a different print density.

(Means for Solving the Problems) As a result of repeated research to solve the above problems, the present inventors have found that:
Each of a plurality of print heads with different printing densities is made into a unit, and each of the units and the printer body is mechanically attached to the printer body and electrically connected to the printer body. The present invention was completed by focusing on the fact that it is sufficient to control the head according to the print density of the attached and connected head.

That is, in the present invention, one of a plurality of predetermined types of fixed scanning print head units each having different printing densities is mechanically attached to the printer main body so as to be replaceable with another print head unit, and is electrically connected. and means for detecting the print density of the print head unit attached and connected, and the print head on the unist is controlled in accordance with the print density detected by the detection means. A printer using a solid-state scanning printhead is provided.

[Function] According to the printer of the present invention, when it is desired to change the print density, the print head unit currently in use can be replaced with a previously prepared print head unit with a different print density that can be installed and connected to the printer main body, making it easy to change the print density. You can change the printing density.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of the entire embodiment.

This printer includes a photoreceptor drum 11 in the center, around which are a charger 12, a print head unit 3, a developer 13, a transfer/separation charger 14,
A cleaner 15 and an eraser 16 are arranged in sequence.

On the upstream side of the charger 14 (on the left side in the figure), there is a paper feed section 17,
An intermediate conveyance roller 18 and a timing roller 19 are arranged, and a transfer paper conveyance heald 20, a fixing device 21, a paper discharge roller 22, and a paper discharge tray 23 are arranged downstream of the charger 14 (on the right side in the figure).

The print head unit 3 has a printing density of 300 dpi and has an external appearance as shown in FIG. 2, and its head has a cross-sectional structure as shown in FIG.

That is, it includes a print head 31 extending in the direction of the rotational axis of the photoreceptor drum 11, a power connector 32 wired to the head, and a control signal connector 33 wired to the head, which are supported by a unit case 34. has been done.

The head 31 includes an LED array 311, a convergent light transmitting array (referred to as a selfoc lens array) 312 below the array, and a shift register 35, a latch register 36, and an LED driver 37 shown in FIG. I'm here.

The case 34 of the print head unit has a handle 341 on its lower side and a groove 342 on its side. This case 34 is placed on a support frame (not shown) of the printer main body 10, and the groove 34 on the side fits into a guide rail (not shown) of the printer main body, so that the handle 34
1, it can be attached to and removed from a predetermined position within the printer body.

The printer main body 10 has a power connector 4 connected to the power connector 32 and a control signal connector 5 connected to the control signal connector 33, as shown by the two-dot chain line in FIG.
And a photo ink club Taro is provided.

The photo ink label is for detecting the print density of the print head 31, and is shielded from light by a light shielding member 343 on the unit case 34 when the unit 3 is housed in a predetermined position within the main body.

That is, the fact that the printing density of the unit 3 is 300 dp1 is detected by the light shielding member 343 of the unit case 34 shielding the photointerrupter 6 on the main body side when the unit 3 is installed in a predetermined position of the printer main body 10. Ru.

On the other hand, this print head unit 3 has a different printing density,
For example, when you want to replace the print head unit with a 400 dpi print head unit, do not provide a light shielding member on the unit case so that the photo interrupter 6 on the main body side is not blocked from light even when the unit is installed in the printer main body. , 400 dpi print head unit is installed.

Further, the power connector 4 and control signal connector 5 on the main body side are configured to be connectable to a power connector and a control signal connector (not shown) of a 400 dpi print head unit, respectively;
The power connector and control signal connector of the i-print printer unit may also be configured to be connectable to the power connector 4 and control signal connector 5 on the main body side.

The printer main body 10 is provided with a print head control section 7 for controlling a print head 31 and a bitmap type data processing device 8 connected thereto.

A data processing device 9 other than the printer (various types of general purpose and non-general purpose devices can be considered) is connected to this data processing device 8 via a file buffer 91 . In addition,
In order to improve throughput, data from the data processing device 9 is temporarily stored in a file buffer 91 and then output to a printer.

As shown in FIG.
A program counter/timer 72 and a selector 73 are connected to the microcomputer 71, and the selector 73 has a clock generator 74 for a print density of 300 dpi and a clock generator for a print density of 400 dpi. device 75 is connected.

The dpi detection signal from the photointerrupter 6 is configured to be input to a microcomputer 71, and the computer 71 outputs this signal to the data processing device 8 via the lotus B1 and processes the data as necessary according to this signal. The selector 73 is switched and the set value of the program counter/timer 72 is changed.

The program counter/timer 72 outputs the clock signal from the selected clock generator 74 or 75 as a shift clock signal to the shift register 35 of the print head unit 3, and also outputs a latch signal and a strobe signal at the timing shown in FIG. It outputs to the latch register 36 and the LED driver 37 of the unit 3, respectively. Further, a line periodic signal (main scanning synchronization signal) is outputted to the device 8 via path B2 as a start signal.

On the other hand, the bitmap type data processing device 8 has a well-known configuration and a detailed explanation thereof will be omitted. It is output in synchronization with the periodic signal and input to the shift register of the print head 31 via the head control section 7.

In the print head 31, one line of image data is transferred to a shift register 35 in synchronization with a shift clock that is output using a line periodic signal (main scanning synchronization signal) as a start signal.
After the input of one line of image data is completed, a latch signal is input and the image data is latched into the latch register 36. Thereafter, a strobe signal is input using the next line synchronization signal as a start signal, and based on the image data latched in the latch register 36, the LED driver 37 lights up the LEDs of the LED array 311 according to the data, and the photoreceptor 11 to expose.

According to the printer described above, the photosensitive drum 11 is rotationally driven in the counterclockwise direction in the drawing by a driving means (not shown), and its surface is uniformly charged by the charging charger 12. Image data is exposed from the print head unit 3 to the charged area.

This image data is based on the print density of unit 3 of 300 dpi.

When the electrostatic latent image is thus formed on the photoreceptor drum 11, this latent image is developed by the developing device 13 and becomes a toner image. This toner image is transferred from the paper feed section 17 to the intermediate conveyance roller 1.
8 and a timing roller 19 to a transfer section, the transfer paper is transferred by a charging member 14, and the transfer paper is separated from the photoreceptor drum 11. The separated transfer paper is conveyed by a conveyance belt 20 to a fixing device 21, where the toner image is fixed, and then discharged onto a paper discharge tray 23 by a paper discharge roller 22.

After the toner image is transferred, the toner remaining on the drum 11 is removed by a cleaner 15, and the residual charge is erased by an eraser 16.

Next, details of image exposure by the print head unit 3 and the 400 dpi unit will be explained with reference to FIG.

In FIG. 5, the clock signal and shift clock signal are shown with one line drawn every 300 pulses to make it easier to understand the clock intervals and the like.

As can be seen from this figure, the shift clock signal is generated at the same timing as the clock signal. For example, when the transfer paper size is A4 and the print density is 300 dpi, the shift clock signal is from the rise of the pulse of the signal indicating the line period (the time required to write one line in the main scanning direction) until the rise of the next pulse. 8.4 inches x 300dp during the time (TA)
Occurs i-2520 times. When using a print head unit with a print density of 400 dpi, the time (TB)
During this period, 8.4 inches x 400 dpi = 3360 pulses are generated.

In this example, it is assumed that the system speed such as the rotational speed of the photoreceptor remains constant even if the print head unit is changed.

The time TA and Tel are determined by the system speed of the printer, and if 4 sheets of A4 size paper are printed per minute, at 300 dpi, T s = 60 se
c/11.8 inch x 4 sheets x 300 dpi = 4.
2m5ec (Actually, in order to convey two or more sheets of print paper in sequence, a certain amount of space is required between the sheets, so the value is smaller.)

In this example, the clock frequency is determined so that data can be transferred to the print head 31 at this time per line in the main scanning direction.

The pulse interval of the line periodic signal at each pixel density, T
A/T m will be 4/3. The reason why the pulse interval of the line periodic signal is increased by 4/3 is that the LED print head unit can move from 300 dpi to 400 dpi in the main scanning direction.
Since the pixel density is changed to i, the pixel density is naturally increased by 473 times, and the purpose is to adjust the magnification in the sub-scanning direction to this.

A latch signal and a strobe signal are also determined according to this line periodic signal.

Next, the operation of the microcomputer 71 will be explained with reference to the flowcharts of FIGS. 6 and 7.

FIG. 6 shows the main routine for control by the microcomputer 71. According to this routine, when the microcomputer 71 is reset and the program starts, step S
Use l to initialize the microcomputer, such as clearing the RAM and setting registers, and initializing the printer to its initial state.

Subsequently, subroutines are sequentially called in steps S2 and S3, and then it is determined in step S4 whether or not there is a print request, and if there is, the subroutines are successively called in step S5,
A subroutine is called in S6 and the process returns to step S3.

If there is no print request in step S4, step S4
6 is performed, and the process returns to step S3.

Step S2 is a dpi switching processing routine that switches the printing density dpi as necessary, step S3 is a print data reception routine in the bitmap type data processing device 8, and step S5 is a routine for developing the received data into a bitmap. and a print processing routine for printing the developed data, and step S6 is an error processing routine.

In the dpi switching routine of step S2, as shown in FIG. 7, first, in step 321, a dp1 detection signal is received from the photointerrupter 6, and it is determined which printing density the LED print head is attached, and in step 322, a dpi detection signal is received from the photointerrupter 6. A dpi signal corresponding to the signal input is output to the data processing device 8.

Next, in step 323, it is determined whether the installed LED print head is of 300 dpi, and the 300 dp
When i, the clock generator 74 is selected in step S24, and in step S25, values such as 3000 for line period signal generation and 2520 for shift clock signal generation are set in the program counter/timer 72, and the main routine is started. Return to. On the other hand, when it is determined in step S23 that the dpi is 400 dpi, the clock generator 75 is selected in step S26, and a value such as 4500, 3360, etc. is set in step S27 as in step S25.

8 and 9 show another embodiment, in which FIG. 8 is a block circuit diagram of the print head control section 70, and FIG. 9 is a timing chart similar to FIG. 5.

In this embodiment, there is only one clock generator 75 that generates a high frequency pulse for 400 dpl.
When the pixel density is changed from 400 dpi to 300 dpi, as shown in FIG.
00dp Data is sent to print head 3 at the same speed as i.
1, and the line period signal is transferred to the program counter/
The number of clock counts input to the timer 72 is 400.
At 300 dpi, it occurs once every 6,000 times, whereas it was every 4,500 times at dpi.

Note that the present invention is not limited to the above embodiments,
Other embodiments are also possible.

For example, a dpi detection signal from the photo interrupter 6 is transmitted to the bitmap processing device 8 via the microcomputer 71 and the lotus B1. An image may be created that corresponds to the pixel density of the print head unit being used. Since this process can be performed by using a well-known scaling process for digital images, a detailed explanation will be omitted here.

In addition to the photo ink printer, as a dpi detection means, for example, an empty bottle insertion terminal is provided in the control signal connector 5 of the printer main body, and this terminal is connected to the control signal connector 33 of the 300 dpi print head unit. An empty bottle to be short-circuited is provided, and such an empty pin is not provided for a 400 dpi print head, and the printing density of the print head unit can be detected by shorting or opening the empty pin insertion terminal of the connector 5. Conceivable.

Furthermore, an intermediate connector may be used to connect the print head unit and the power connector and control signal connector of the printer main body, if necessary.

Furthermore, when forming a print head unit, a unit to which the present invention is applicable may be assembled by attaching an appropriate attachment to an existing print head or print head unit.

Note that the embodiments described above all utilize an LED print head, but the present invention uses a liquid crystal, PLZT
, an EL array, or the like.

〔Effect of the invention〕

As explained above, according to the present invention, in a printer using a solid-state scanning print head, the print density can be easily changed by changing the print head unit on the user side according to the font, printing purpose, etc. It has the advantage that it can be used effectively.

Further, according to the present invention, there are the following advantages.

■ If the reading density of image data read with an image scanner and the printing density are different, in the case of raster data,
However, according to the present invention, the density of the output system can be changed according to the density of the reading system.

■ When using printers with different print densities in emulation mode, you can select the print density that is most suitable for emulation.

■ If the printer is equipped with a controller that supports Post Script (Post 5script), data written in the Post Script language can be printed regardless of the print density of the printer, and the size does not depend on the density. The print quality differs depending on the print density of the printer, and the time required for printing (the time required to develop bit data into a bitmap) also differs. However, even in such a case, according to the present invention, if page buffer memory is secured, DP from the print head unit can be
The i information makes it easy to output data according to the printing density.

Therefore, the user can select the printing density and printing speed depending on the application.

For example, a manuscript in the editing stage can be printed at high speed at 300 dpi, and a final draft can be printed finely at 400 dpi. Simply put, the amount of memory is about 1.8 times different, so the speed is also about 1.8.
It will be twice as different. This difference cannot be ignored in practical terms.

■ Solid-state scanning printheads such as LED printheads become more expensive as the printing density improves, and at the same time the amount of memory required also increases at a square rate. After that, you can upgrade to a higher-end model with higher print density relatively easily depending on your budget.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the overall configuration of an embodiment of the present invention, Fig. 2 is a schematic perspective view of a print head unit, Fig. 3 is a sectional view of the print head, and Fig. 4 is a block diagram of the control circuit of the printer. , FIG. 5 is a timing chart showing the timing of generation of various signals from the print head control unit, FIG. 6 is a flowchart showing the main routine of the operation of the microcomputer in the control circuit, and FIG. 7 is a dpi luminance switching in the main routine. FIG. 8 is a block diagram of a control circuit in another embodiment, and FIG. 9 is a timing chart similar to FIG. 5 in the other embodiment. 10... Printer body 3... Print head unit 31... Print head 32.4... Power connector 33.5... Control signal connector 6... Photo interrupter 34... Case 343... - Light shielding member 7.70...Print head control section 8...
Bitmap type data processing device 9...General-purpose data processing device 91...File buffer 71...Microcomputer 72...Program counter and timer 74.75
... Clock generator 35 ... Shift register 36 ... Latch register 37 ... LED driver 10 ... Printer main body Figure 2 32.4 ... Power supply connector 33.5 ... Control signal connector 6... Interrupter 4... Case 343... Light shielding member Figure 5 data □ At 400dp1 1 450o times
. Strobe Figure 6 Figure 7 Figure 8 Factor 70...Print head control section Figure 9 Strobe Boo-j-11111111! strobe

Claims (1)

[Claims] (1) One of the predetermined types of fixed scanning print head units with different print densities is mechanically attached to the printer body so that it can be replaced with other print head units, and is electrically connected. , a solid state characterized in that means is provided for detecting the print density of the print head unit mounted and connected thereto, and the print head on the unit is controlled in accordance with the print density detected by the detection means. A printer that uses a scanning printhead.