JP3348089B2 - Printing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus capable of switching print density.

[0002] Printing devices such as electrophotographic printing devices, thermal transfer printing devices, and ink jet printing devices are widely used in output devices such as computers, copiers, and facsimile machines.

In such a printing apparatus, the toner, the thermal transfer ink ribbon, the ink cartridge, and the like are consumables,
Replaced by the user.

[0004] With the recent increase in the use frequency of printing devices,
There is a demand to reduce the amount of toner and the like used, thereby reducing the cost of consumables (running cost).

[0005]

2. Description of the Related Art An electrophotographic printing apparatus or the like is provided with a print density adjustment designating means so that an operator can adjust the print density by adjusting the designating means to a desired print density.

When the print density is set to be low by the print density adjustment, the toner amount is reduced as a result, and when the print density is set to be high, the toner amount is increased as a result.

The print density adjusting function is provided for performing printing at an optimum density, and is not for adjusting the amount of toner used, but as a result, the amount of toner is adjusted. Is done.

[0008]

By the way, in general, a document to be submitted is emphasized in print quality, and it is desired to always print in black, and a document for manuscript can be read even if the print is thin. Sometimes it's good.

For this reason, it is desired to perform both printing with an emphasis on print quality and printing with an emphasis on reducing the amount of printing consumables used. However, the prior art has the following problems.

The conventional print density adjusting function is essentially
This is a fine adjustment when the print quality is emphasized, and it is difficult to adjust the print density to a readable level.

Since the adjustment is performed by the operator, the individual difference of the operator is reflected in the adjustment, and the effect of reducing the printing consumables is small.

[0012] Since the operator needs to make fine adjustments one by one, it takes time and effort to make adjustments.

Therefore, according to the present invention, an optimum print density is automatically determined according to a normal mode in which printing quality is emphasized and an economy mode in which running cost is emphasized.
An object of the present invention is to provide a printing apparatus that can reduce printing consumables.

Further, the present invention provides a printing apparatus capable of automatically determining an optimum print density in accordance with a normal mode in which printing quality is emphasized and an economy mode in which running cost is emphasized, thereby reducing a toner amount. It is an object of the present invention to provide a print control device for controlling the printing.

[0015]

FIG. 1 is a diagram illustrating the principle of the present invention.

The present invention is configured as follows in order to solve the above-mentioned conventional problems.

(1): A printing mechanism 1 for performing printing in accordance with print data, and a detector for obtaining information corresponding to the toner density related to the printing density on the printing medium by the printing mechanism 1 A printing device,
It has a density change instruction switch for adjusting the print density in the normal mode, and selection instruction means capable of manually selecting and instructing the normal mode and the economy mode. When the normal mode is manually instructed, the detection is performed. The first amount of color material set in accordance with the instruction of the normal mode based on the output of the printing unit by the printing mechanism unit 1 so that the printing density on the printing medium becomes the first printing density. Is controlled so that printing is performed under the first printing condition, and when the economy mode is instructed manually, based on the output of the detector, the second mode set corresponding to the economy mode instruction is set. Printing of the color material of the amount 2 is performed under the second printing condition by the printing mechanism unit 1 so that the printing density on the printing medium becomes the second printing density which is lower than the first printing density. When the instruction is switched from the normal mode instruction to the economy mode instruction, the output of the detector indicates that the print density on the print medium is higher than the second print density. Is controlled to be performed.

(2) The printing apparatus according to (1),
When the mode is switched from the normal mode instruction to the economy mode instruction, the output of the detector is changed to the print density on the print medium.
When it is instructed that the degree becomes lower than the second print density , control is performed so that the print density becomes the second print density, and printing is performed.

[0019]

[Operation] The operation based on the above configuration will be described.

[0021] When the normal mode is instructed by hand on the basis of the output of the detector, the printing of the first amount of colorant that is set corresponding to the instruction of the normal mode to the printing medium by the printing mechanism portion 1 Control is performed so that the printing is performed under the first printing condition for setting the density to the first printing density. When the economy mode is manually instructed, the printing is performed based on the output of the detector. , Economy mo
The second amount of color material set in response to the
The print density on the print medium is changed by the printing mechanism 1 to the first mark.
The printing is controlled under the second printing condition so that the second printing density is lower than the printing density . When the instruction is switched from the normal mode instruction to the economy mode instruction, the output of the detector is output. Indicates that the print density on the print medium is the second mark
Even if it indicates that the printing density is higher than the printing density , the printing is controlled to be performed. For this reason, normal mode instruction
When switching to the economy mode instruction at the beginning, printing is performed at a density higher than the density specified in the economy mode instruction, but printing can be started quickly without waste of color material as toner.

Further, when the instruction is switched from the normal mode instruction to the economy mode instruction, the output of the detector becomes
When it is instructed that the print density on the print medium is lower than the second print density , control is performed so that the print density becomes the second print density, and printing is performed. Therefore, the print density can be automatically reduced to a readable level.

Further, the print density in the normal mode is changed by the density change instruction switch. Therefore, in the normal mode, the print density can be changed according to the preference of the operator.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (a) Description of Printing Apparatus FIG. 2 is a configuration diagram of a printing apparatus and shows an example of an electrophotographic printing apparatus.

In FIG. 1, a printing mechanism 1 is constituted by an electrophotographic printing mechanism, and is provided around a rotating photosensitive drum 10.
Charger 11, optical image writing unit 12, toner supply unit 1
4, a developing device 13 having a transfer device 4, a transfer device 15, an AC neutralizer (separator) 16, and a cleaning unit 17 are provided.

The optical image writing section 12 includes a light emitting source (semiconductor laser) 120, a polygon mirror (optical scanner) 121 for optically scanning the light from the light emitting source 120, and a photosensitive drum 1 for scanning light.
And a mirror 122 leading to zero.

The developing device 13 is a magnetic roller 1 for supplying a two-component developer composed of a toner and a carrier to the photosensitive drum 10.
30, a supply roller 131 for supplying a two-component developer to the magnetic roller 130, a stirring roller 132 for stirring the carrier and the toner, and a flow plate 133 for guiding the remaining developer of the magnetic roller 130 to the stirring roller 132. A toner density sensor (magnetic permeability sensor) 134 that detects the magnetic permeability of the component developer and generates a toner density detection output.

The toner supply section 14 includes a toner storage section (toner cassette) 140 storing toner, a supply roller 141 for supplying toner from the toner storage section 140 to the developing device 13, and a toner supply roller 141. It has an agitating roller 142 for feeding and a supply motor 143 for rotating the supply roller 141.

The operation of the electrophotographic printing mechanism is, as is well known, that the photosensitive drum 10 is uniformly charged by the charger 11 and the light of the light emitting source 120 driven by the video signal is optically scanned by the polygon mirror 121. 122 to the photosensitive drum 1
0 is subjected to line exposure, an electrostatic latent image is formed, the toner is developed by the developing device 13, and the transfer device 1 is transferred to the sheet fed by the transport roller 30.
5 transfers the toner image on the photosensitive drum 10 to the AC
At 6, the paper is separated from the photosensitive drum 10.

After the transfer, the photosensitive drum 10 is cleaned of residual toner by a cleaning brush and a blade of a cleaning unit 17, and the separated paper is sent to a fixing device.
The toner image is fixed.

On the other hand, the print control unit 2 includes a control unit (MPU) 20 storing the designated toner density N in the normal mode, the designated toner density E in the economy mode, the normal mode key 21a and the economy mode instruction key 21b. A / D that converts the detection voltage of the operation panel 21 including the detection unit and the toner density sensor 134 into a digital value and inputs the digital value to the control unit 20
(Analog / Digital) Converter 22 and Control Unit 20
And a motor drive circuit 23 for driving the supply motor 143 in accordance with the instruction.

The control unit 20 controls the optical image writing unit 12 and the like based on print information (including video information) from a main control unit (not shown) to control toner density.

The operation will be described. When the economy mode key 21b on the operation panel 21 is pressed, the control unit 2
0 is the designated toner density E in the economy mode (for example,
3 wt%) and control the toner concentration.

That is, the controller 20 controls the toner density sensor 1
The detected voltage at 34 is periodically read through the A / D converter 22 and is compared with the designated toner density E. When the detected toner density based on the detected voltage becomes equal to or less than the designated toner density E, the motor driving unit 23 controls the supply motor 143 to a constant After a time rotation, the supply roller 141 rotates to supply a certain amount of toner.

As a result, the toner density is controlled to the designated toner density E, and the print density becomes thin enough to be read.
In document printing, toner can be saved.

On the other hand, when the normal mode key 21a of the operation panel 21 is depressed, the control unit 20 selects the designated toner concentration N (for example, 6 wt%) in the normal mode,
Control the toner density.

That is, the controller 20 controls the toner density sensor 1
The detection voltage at 34 is periodically read through the A / D converter 22 and is compared with the specified toner density N. When the detected toner density based on the detection voltage becomes equal to or less than the specified toner density N, the motor driving unit 23 controls the supply motor 143 to be constant. After a time rotation, the supply roller 141 rotates to supply a certain amount of toner.

As a result, the toner density is controlled to the designated toner density N, and the print density becomes a density at which the print quality is sufficient, which is suitable for printing a document to be submitted.

As described above, the print density is changed by changing the toner density in accordance with the normal / economy instruction. In the normal mode, printing is performed with a sufficient print quality, and in the economy mode, the print is readable. Printing is performed at a print density of the order, and toner saving is automatically executed.

Since the toner density is automatically set, it is possible to set a print density that is readable and an efficient setting of toner saving, and to achieve the maximum toner saving while maintaining the required print density. It becomes possible.

Further, since it is realized by controlling the toner density, it is possible to reduce the consumption of printing consumables relatively simply and effectively.

(B) Description of the replenishing unit FIG. 3 is a block diagram of the replenishing unit, FIG. 4 is a characteristic diagram of the toner density detector of the present invention, and FIG. 5 is a block diagram of the present invention.

3 and 5, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and 18 is a heat fixing device, which heats the toner image on the sheet onto which the toner image has been transferred. A belt for fixing and discharging, 31 is a conveyor belt,
A toner density sensor 135 for promoting the separation of the paper separated by the static eliminator 16 and sending the paper to the heat fixing device 18,
It is composed of a D (optical density) sensor, has a light emitting section and a light receiving section, and optically detects a toner mark on the photosensitive drum 10 to detect the toner density.

As described above, the toner density sensors 134 and 13
The reason for providing 5 is that, as shown in FIG. 4 (A), the OD sensor 135 saturates the toner density versus sensor output when the toner density exceeds about 5 wt%, and the linear characteristic range is as follows. 1 to 5 wt%, and the magnetic permeability sensor 134 described above.
As shown in FIG. 4B, when the toner concentration becomes about 3 wt% or less, the output is saturated and the linear characteristic range is 3 to 8 wt%.

Therefore, when the toner density is 6 in the normal mode,
In order to control the toner concentration in a wide range, such as 3 wt% in the economy mode and the toner concentration in the economy mode, the toner sensor in the economy mode cannot be satisfactorily controlled only by the magnetic permeability sensor 134, and the reverse control is performed only by the OD sensor 135. Therefore, the toner control in the normal mode cannot be properly performed.

For this reason, as shown in FIG. 5, two toner density sensors 134 and 135 having different linear characteristics are set to A / A.
It is connected to the D converter 22 and one of the detection outputs is selected by the sensor selection signal of the control unit 20 to realize a wide range of toner density control.

Further, in this embodiment, the normal mode key 21a and the economy mode key 21
In addition to b, a density change instruction switch 21c for adjusting and changing the print density in the normal mode according to the operator's preference and a bar display type LED display unit 21d for displaying the indicated density value are provided. ing.

FIG. 6 is a processing flowchart of the present invention, and FIG. 7 is an explanatory diagram of the operation of the present invention.

The operation will be described. When the economy mode key 21b of the operation panel 21 is pressed, the control unit 2
0 sets the economy mode flag, and the operation panel 21
When the normal mode key 21a is pressed, the control unit 2
0 resets the economy mode flag.

In the toner concentration control routine shown in FIG.
The control unit 20 determines the economy mode based on the flag.

In the economy mode, the controller 20 controls the designated toner density E (for example, 3 wt%) in the economy mode.
Is selected, and the A / D converter 2
2 is instructed to select the output of the OD sensor 135, the detected voltage of the OD sensor 135 is read via the A / D converter 22, and compared with the slice value E of the designated toner density. Then return to the steps.

Conversely, if the control unit 20 determines that the detected voltage is lower than the slice value E of the specified toner density, it determines that the detected voltage is lower than the specified toner density, and the mode driving unit 23 rotates the supply motor 143 for a predetermined time. Supply roller 141
With the rotation of, a certain amount of toner is supplied, and the process returns to the step.

As a result, the toner density is controlled to the designated toner density E, and the print density becomes thin enough to be read.
In document printing, toner can be saved.

On the other hand, in the normal mode, the control unit 20
Is the designated toner density N in the normal mode (for example, 6w
(slice value corresponding to t%), instructs the A / D converter 22 to select the output of the magnetic permeability sensor 134, reads the detection voltage of the magnetic permeability sensor 135 via the A / D converter 22, and reads the specified toner density. Compare with slice value N,
If the detected voltage is equal to or less than the slice value N of the designated toner density, the process returns to the step.

Conversely, if the control unit 20 determines that the detected voltage is higher than the slice value N of the designated toner density, it determines that the detected toner density is lower than the designated toner density, and causes the motor driving unit 23 to rotate the supply motor 143 for a predetermined time. Supply roller 141
With the rotation of, a certain amount of toner is supplied, and the process returns to the step.

As a result, the toner density is controlled to the designated toner density N, the print density is increased, the print quality is sufficient, and it is suitable for printing a submission document.

As described above, as shown in FIG. 7, the print density is changed by changing the toner density in accordance with the normal / economy instruction. In the normal mode, the print density is set to a sufficient print density. In the economy mode, printing is performed at a print density that can be read, and toner saving is automatically performed.

At this time, when the mode is changed from the economy mode to the normal mode, the toner density in the developing unit 13 is reduced to 6% by weight in the normal mode by supplying toner.
Do not print until.

On the other hand, when the mode is switched from the normal mode to the economy mode, the toner concentration in the developing unit 13 needs to be reduced from 6 wt% to 3 wt%.

In this method, even if the mode is replaced with the economy mode, printing is continued at the same toner density and the toner density is reduced to 3 wt% by printing, or charging, exposure, development, and cleaning are performed, and the toner adheres to the photosensitive drum 10. The toner is collected by cleaning, the toner is discarded, and when the toner density reaches the economy mode designated density,
There is a way to start printing.

The former method has no waste of toner. However, even in the economy mode, printing is initially performed at a density higher than the designated density in the economy mode. Can be printed with the specified density.

The OD sensor 135 and the magnetic permeability sensor 13
By using together with No. 4, such a wide range of toner density control can be satisfactorily realized.

FIG. 7B shows that the photosensitive drum 10 is composed of amorphous silicon, the carrier of the two-component developer is a magnetite carrier, and the toner is a polyester toner. The peripheral speed of the photosensitive drum 10 is 264 mm. / Se
c, the diameter of the magnetic roller 130 of the developing device 13 is 50 mm,
Circumferential speed 250 rpm, gap of doctor blade 1.
2 mm, the developing gap is 1.0 mm, the developing section charging potential of the photosensitive drum 10 is 430 V, and the developing bias voltage is 2
The result of an experiment at 40 V is shown.

At this time, when the designated toner density in the normal mode is 6 wt%, the solid density is 1.25 or more, the line drawing density is 1.30 or more, and the toner consumption is 1
The weight was 340 g per 10,000 pages.

On the other hand, when the designated toner density in the economy mode is set to 3 wt%, the solid density becomes 1.0 to 1.1.
0, the line drawing density was 1.20 or more, and the decoding of characters was sufficient.

The amount of toner consumption is 2 per 10,000 pages.
It was 40 g.

As a result, in the economy mode, about 30
% Of toner can be saved, and running cost can be reduced.

(C) Description of Switching Laser Emission Intensity FIG. 8 is a block diagram showing a case where the laser emission intensity is switched according to the present invention, and FIG. 9 is an operation explanatory diagram showing a case where the laser emission intensity is switched according to the present invention.

In FIG. 8, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and 24 is a laser drive circuit, which is a laser light source 120 according to a video signal with a current corresponding to a designated intensity. Is a high voltage power supply for applying a developing bias voltage VB to the magnetic roller 130 of the developing unit 13.

The operation will be described with reference to FIG. 9. When the normal mode is designated by the normal mode key 21a, the control unit 20 switches the drive current of the laser drive circuit 24 to a large current.

As a result, the laser light source 120 emits light in accordance with the video signal with a large current, and the light emission intensity becomes large.
As shown in (A), the potential of the exposed portion becomes as low as VL1, and the difference from the developing bias voltage VB (VB-VL1).
Is great.

The toner proportional to the difference voltage is supplied to the developing device 1
3, the print density becomes high, the print quality becomes sufficient, and the print document is suitable for printing.

At this time, the current value given to the laser light source 120 is changed according to the density instruction information specified by the density instruction switch (FIG. 5).

Accordingly, the print density is changed within a range suitable for printing a document to be submitted.

Further, the charging voltage may be changed according to the density instruction information.

Conversely, when the economy mode is designated by the economy mode key 21b, the control unit 20 switches the drive current of the laser drive circuit 24 to a small current.

As a result, the laser light source 120 emits light according to the video signal with a small current, and the light emission intensity becomes small.
As shown in (B), the potential of the exposed portion becomes higher like VL2, and the difference from the developing bias voltage VB (VB-VL1).
Is small.

The toner in proportion to the difference voltage is supplied to the developing device 1
3, the print density is reduced, and toner can be saved in the printing of an original.

As described above, by changing the difference between the developing bias voltage VB and the exposure portion potential VL in the printing process mechanism for controlling the printing density by the emission intensity, the developing density can be controlled to be high or low, and the toner consumption can be controlled. We can save quantity.

In this example, a two-component developer is shown, but the invention can also be applied to a one-component developer.

(D) Description of Switching of Developing Bias Voltage FIG. 10 is a configuration diagram of switching the developing bias voltage of the present invention, and FIG. 11 is an explanatory diagram of an operation of switching the developing bias voltage of the present invention.

In FIG. 10, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and 24 is a laser driving circuit, which is a laser light source 120 according to a video signal with a current corresponding to a designated intensity. And 25, a high-voltage power supply for applying the specified developing bias voltages VB1 and VB2 to the magnetic roller 130 of the developing device 13.

The operation will be described with reference to FIG. 11. When the normal mode is designated by the normal mode key 21a, the control unit 20 sets the developing bias voltage of the high voltage power supply 25 to a large V.
Switch to B1.

As a result, the developing unit 13 develops with the large developing bias voltage VB1, and as shown in FIG.
The difference (VB1−VL) between the potential VL of the exposed portion and the developing bias voltage VB1 is large.

The toner proportional to the difference voltage is supplied to the developing device 1
3, the print density becomes high, the print quality becomes sufficient, and the print document is suitable for printing.

Conversely, when the economy mode is designated by the economy mode key 21b, the control unit 20 switches the developing bias voltage of the high voltage power supply 25 to a small VB2.

As a result, the developing device 13 develops with the small developing bias voltage VB2, and as shown in FIG.
The difference (VB2−VL) between the potential VL of the exposed portion and the developing bias voltage VB2 becomes small.

The toner proportional to the difference voltage is supplied to the developing device 1
3, the print density is reduced, and toner can be saved in the printing of an original.

As described above, in the printing process mechanism for controlling the print density by the developing bias voltage, the developing bias voltage VB
And the difference between the exposure portion potential VL and the exposure portion potential VL, the development density can be controlled to be high and low, and the toner consumption can be reduced.

In this example, a two-component developer is shown, but the invention can also be applied to a one-component developer.

(E) Description of Switching between Laser Emission Intensity and Developing Bias Voltage FIG. 12 is a block diagram showing the case of switching between laser emission intensity and developing bias voltage according to the present invention, and FIG. 13 is a diagram showing laser emission intensity and developing bias according to the present invention. FIG. 9 is an explanatory diagram of an operation when switching voltages.

In FIG. 12, the same components as those shown in FIG. 2 are denoted by the same symbols, and a laser driving circuit 24 is a laser light source 120 according to a video signal with a current corresponding to a designated intensity. And 25, a high-voltage power supply for applying the specified developing bias voltages VB1 and VB2 to the magnetic roller 130 of the developing device 13.

The operation will be described with reference to FIG. 13. When the normal mode is designated by the normal mode key 21a, the control unit 20 switches the drive current of the laser drive circuit 24 to a large current and changes the developing bias voltage of the high voltage power supply 25. Great VB
Switch to 1.

As a result, the laser light source 120 emits light according to the video signal with a large current, and the light emission intensity increases.
As shown in FIG. 3 (A), the potential of the exposed portion becomes low as VL1, and the developing device 13 applies a large developing bias voltage VB1.
And a developing bias voltage V
The difference (VB1-VL1) from B1 is large.

The toner proportional to the difference voltage is supplied to the developing device 1
3, the print density becomes high, the print quality becomes sufficient, and the print document is suitable for printing.

Conversely, when the economy mode is designated by the economy mode key 21b, the control unit 20 switches the drive current of the laser drive circuit 24 to a small current, and
5 is switched to a small VB2.

As a result, the laser light source 120 emits light with a small current according to the video signal, and the light emission intensity becomes small.
As shown in FIG. 3 (B), the potential of the exposed portion becomes high like VL2, and the developing device 13 applies a small developing bias voltage VB2.
And a developing bias voltage V
The difference (B2−VL2) from B2 is small.

The toner in proportion to the difference voltage is supplied to the developing device 1
3, the print density is reduced, and toner can be saved in the printing of an original.

As described above, the first printing process mechanism for controlling the printing density by the light emission intensity and the second printing process mechanism for controlling the printing density by the developing bias voltage have the developing bias voltage VB and the exposure section potential. By changing the difference from VL, the development density can be controlled to be high and low, and the toner consumption can be reduced.

In this example, a two-component developer is shown, but the invention can also be applied to a one-component developer.

Further, since the control is performed by both the exposure intensity and the developing bias voltage, the setting of the designated print density becomes easy.

(F) Description of Other Embodiments In addition to the above-described embodiments, the present invention can be modified as follows.

Although the printing apparatus has been described as an electrophotographic printing apparatus, in a thermal transfer printing apparatus, it is possible to save thermal transfer ink on a thermal transfer ribbon by changing a heating current.
In the ink jet printing apparatus, ink can be saved by controlling the ink jetting amount, and in the impact printing apparatus, the life of the ink ribbon can be extended.

Although the printer has been described, the present invention can be applied to a printing apparatus such as a copying machine and a facsimile.

Various combinations such as a combination of toner density control and exposure intensity control, a combination of toner density control and development bias voltage control, and the like may be applied.

Although the normal / economy instruction is given from the operation panel, it may be given from a host computer or the like.

As described in the embodiments of the present invention, the print density of the printing mechanism is divided into a sufficient print quality and a readable print quality according to the normal / economy instruction. In addition to reducing the consumption of printing consumables and contributing to the reduction of running costs, the consumption of toner and ink containing harmful substances is small, and the environmental pollution when discarded can be reduced. Further, in the economy instruction, since the print density is controlled to an appropriate level that can be read, the adjustment by the operator is not required, and the labor is not required. Furthermore, various modifications are possible within the scope of the present invention, and these are not excluded from the scope of the present invention.

[0108]

As described above, according to the present invention,
The following effects are obtained.

[0109]: When the normal mode is designated manually on the basis of the output of the detector, the printing of the first amount of colorant that is set corresponding to the instruction of the normal mode to the printing medium by the printing mechanism portion Control is performed so that the printing is performed under the first printing condition for setting the density to the first printing density. When the economy mode is manually instructed, the printing is performed based on the output of the detector. , Economymo
The second amount of color material set in response to the
The print density on the print medium is changed by the printing mechanism to the first mark.
The printing is controlled under the second printing condition so that the second printing density is lower than the printing density . When the instruction is switched from the normal mode instruction to the economy mode instruction, the output of the detector is output. Indicates that the print density on the print medium is the second mark
Because even shows that the darker than printing density becomes controlled to perform printing, eco from the instruction in the normal mode
At the initial stage of switching to the economy mode instruction, printing is performed at a density higher than the density specified in the economy mode instruction, but printing can be started quickly without waste of color material as toner.

When the instruction is switched from the normal mode instruction to the economy mode instruction, the output of the detector is printed.
If the print density on the medium is instructed to be lower than the second print density , control is performed so that the print density becomes the second print density, and printing is performed.
Can be performed automatically.

Since the print density in the normal mode is changed by the density change instruction switch, the print density can be changed according to the preference of the operator in the normal mode.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a configuration diagram of a printing apparatus according to the present invention.

FIG. 3 is a configuration diagram of a replenishing unit of the present invention.

FIG. 4 is a characteristic diagram of the toner concentration detector of the present invention.

FIG. 5 is a block diagram of the present invention.

FIG. 6 is a processing flowchart of the present invention.

FIG. 7 is a diagram illustrating the operation of the present invention.

FIG. 8 is a configuration diagram when switching the laser emission intensity according to the present invention.

FIG. 9 is an explanatory diagram of an operation when the laser emission intensity is switched according to the present invention.

FIG. 10 is a configuration diagram when the developing bias voltage of the present invention is switched.

FIG. 11 is an explanatory diagram of an operation when the developing bias voltage of the present invention is switched.

FIG. 12 is a configuration diagram when switching between the laser emission intensity and the developing bias voltage according to the present invention.

FIG. 13 is a diagram illustrating the operation of the present invention when switching between the laser emission intensity and the developing bias voltage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printing mechanism part (electrophotographic printing mechanism) 2 Printing control part 10 Photosensitive drum (image carrier) 11 Charger 12 Optical image writing part 13 Developing device 14 Toner replenishing part 20 Control part 21 Operation panel 24 Laser drive circuit 25 High voltage power supply 134, 135 Toner density sensor

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoji Hoki 4-1-1, Kamidadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Tomokazu Akutada 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Inside Fujitsu Limited (72) Inventor Akihiro Komuro 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-1-133075 (JP, A) JP-A-1-269951 (JP, A) JP-A-4-221197 (JP, A) JP-A-2-144574 (JP, A) JP-A-2-54282 (JP, A) JP-A-62-164063 (JP) JP-A-55-106470 (JP, A) JP-A-3-184066 (JP, A) JP-A-5-66629 (JP, A) JP-A-5-88494 (JP, A) Patent 327633 ( JP, B2) (58) Survey (Int.Cl. ^7, DB name) G03G 15/00 G03G 15/08 G03G 21/00 - 21/04 G03G 21/14 B41J 2/44 - 2/46 B41J 2/52 - 2/525

Claims (2)

(57) [Claims] 1. A printing apparatus comprising: a printing mechanism for performing printing in accordance with print data; and a detector for obtaining information corresponding to a toner density related to a printing density on a print medium by the printing mechanism. Te has a density changing instruction switch for adjusting the print density in normal mode, alternatively the selection instruction can be selected instruction means manually normal mode and economy mode manually, the normal mode is instructed by manually In this case, based on the output of the detector, the printing amount of the first amount of the color material set in accordance with the instruction of the normal mode on the printing medium by the printing mechanism unit becomes the first printing density. Is controlled so that printing is performed under the first printing condition, and when the economy mode is instructed manually,
Based on the output of the detector, the second amount of the color material set in accordance with the instruction of the economy mode is changed by the printing mechanism unit so that the printing density on the printing medium is lower than the first printing density. 2 so that printing is performed under the second printing condition so that the printing density becomes 2. When the instruction is switched from the normal mode instruction to the economy mode instruction, the output of the detector is output to the print medium. Even if the print density indicates that it is darker than the second print density,
A printing apparatus, which is controlled to perform printing. 2. The printing apparatus according to claim 1, wherein when the instruction from the normal mode is switched to the instruction in the economy mode, the output of the detector is such that the print density on the print medium is the second print density. A printing apparatus characterized in that when it is instructed to make the print density lighter, the printing is controlled so that the print density becomes the second print density.