JPH07134455A - Optical unit for printing device and developing unit for printing device - Google Patents

Abstract

PURPOSE:To cope with high speed printing and the high resolution of printing and to obtain high-quality printing in spite of the dispersion of stirring ability inherent in a developing unit. CONSTITUTION:A data conversion part 3 converting printing data information being a parallel signal from a central control part 1 to printing data information being a serial signal is provided in an optical unit 2, and a laser beam is driven based on the printing data information being the serial signal from the data conversion part 3. A toner concentration correction amount information storage part 5 storing toner concentration correction amount information inherent in the developing unit 4 and a toner concentration control part 6 controlling toner concentration based on the toner concentration correction amount information from the storage part 5 and the printing density information from the control part 1 are provided in the developing unit 4, and the toner concentration is controlled by the control part 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical unit of a printing apparatus which drives a laser beam, and a developing unit of a printing apparatus which controls toner density.

[0002]

2. Description of the Related Art Conventionally, in a printer, charging, latent image formation, development, transfer, fixing,
Each unit is provided for performing an electrophotographic process such as cleaning and charge removal. These electrophotographic processes are executed by controlling each unit by a central control board, which is commonly called a mechanical controller.
Next, regarding the latent image forming process and the developing process,
This will be described with reference to FIG.

First, in the latent image forming process, the parallel conversion is performed in the data conversion unit 31 provided in the central control board 30 of the print data information of the parallel signal from the print data information expansion section (not shown) other than the central control board 30. The print data information of the serial signal converted by the serial conversion is executed by the optical unit 32 supplied from the central control board 30. The optical unit 32 has, for example, a semiconductor laser capable of switching light, and the laser driving unit 3 that drives the semiconductor laser to perform switching based on the print data information of the serial signal.
3. A rotary mirror drive unit 34 having a rotary mirror for irradiating the surface of the photosensitive drum with a laser beam emitted from this semiconductor laser for sub-scanning and driving the rotary mirror, and further detecting the laser beam for sub-scanning. Then, a synchronization signal forming section 35 is provided for forming a synchronization signal which is a latent image formation start position in the main scanning direction. The synchronization signal formed by the synchronization signal forming unit 35 is the same as the central control board 30.
The data is supplied to the data conversion section 31 of FIG. 1 and is subjected to parallel-serial conversion based on the synchronization signal, and the print data information of the serial signal is supplied to the optical unit 32 side in a print synchronized manner. Thus, the optical unit 32 forms an electrostatic latent image corresponding to the print data information on the surface of the photosensitive drum by the laser beam based on the print data information of the serial signal.

Next, the developing process is executed by the developing unit 37 supplied from the central control board 30 with a toner replenishment command output from the toner density control section 36 provided on the central control board 30. The developing unit 37 is provided with a replenishment toner amount control unit 38 that controls the replenishment toner amount based on the toner replenishment command, a toner concentration detection unit 39 that includes a toner concentration sensor, and generates toner concentration information. Has been done. The toner concentration information generated by the toner concentration detection unit 39 is supplied to the toner concentration control unit 36 of the central control board 30,
The toner concentration control unit 36 outputs the toner replenishment command based on the toner concentration information, the print concentration information such as print page information, and the temperature and humidity information. In this way, the developing unit 37 forms the developable toner by adhering the toner to the electrostatic latent image formed on the surface of the photosensitive drum with the toner density controlled based on the toner replenishment command.

[0005]

However, the above-mentioned ones have the following problems because the main control section of the electrophotographic process is provided on the central control board. (A) Optical Unit As the performance and quality of the printing apparatus are improved, the printing apparatus is required to have higher speed and higher resolution. However, although such high speed and high resolution are accompanied by higher frequency of the print data information, there is a problem that it is difficult to serially transmit the print data information from the central control board to the optical unit as described above. is there. (B) Developing unit Even with the same toner concentration information, the actual toner concentration varies due to variations in agitating properties of individual developing units, and the variation in toner replenishment amount causes differences in follow-up to correction control. As a result, there is a subtle difference in the amount of toner attached to the surface of the photosensitive drum. For this reason, even if the toner density is controlled so as to be the same, there is a possibility that the print density may vary, which is unavoidable in improving the quality of printing. SUMMARY OF THE INVENTION The present invention has an object of solving the above problems and provides an optical unit of a printing apparatus which can cope with high speed printing and high resolution printing. Another object of the present invention is to provide a developing unit of a printing apparatus, which is capable of achieving high-quality printing regardless of inherent variations in, for example, agitating property, for the purpose of solving such a problem.

[0006]

The optical unit of the printing apparatus according to the first aspect of the present invention is shown in the block diagram showing the constitution of the inventive principle of the present invention in FIG. 1 in order to achieve the former object. As shown in FIG.
Is provided with a data converter 3 for converting the print data information of the parallel signal from the print data information of the serial signal, and driving the laser beam based on the print data information of the serial signal from the data converter 3.

Further, in order to achieve the latter object mentioned above, the developing unit of the printing apparatus according to the second aspect of the present invention, as shown in the block diagram of FIG. The unit 4 includes a toner density correction amount information storage unit 5 for storing toner density correction amount information unique to the developing unit 4, toner density correction amount information from the toner density correction amount information storage unit 5, and a central control unit 1. The toner density control section 6 controls the toner density based on the print density information from the above, and the toner density control section 6 controls the toner density.

[0008]

In the first aspect of the invention, by providing the data conversion section 3 on the optical unit 2 side, the print data information is parallel-serial converted in the optical unit 2 and the print data information is processed in parallel up to the optical unit 2. Therefore, it is possible to cope with high speed printing and high resolution accompanying the high frequency of the print data information. Second invention: By providing the toner concentration control unit 6 on the developing unit 4 side and providing the toner concentration correction amount information storage unit 5 for storing the toner concentration correction amount information peculiar to the developing unit 4, it is peculiar to the developing unit 4. For example, the toner density can be controlled according to the characteristics of the stirring property and toner lot, and high-quality printing can be performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment in which the optical unit of the printing apparatus and the developing unit of the printing apparatus according to the present invention are applied to an electrophotographic apparatus will be described with reference to the drawings. In FIG. 2, print data information of a parallel signal from a print data information expansion unit, which is formed of a bitmap (not shown) outside the central control board 10, is supplied to the optical unit 11 via the central control board 10. In the optical unit 11, the print data information of the parallel signal is subjected to parallel-serial conversion in the data conversion unit 12 and given to the laser drive unit 13 as the print data information of the serial signal. The laser drive unit 13 is composed of a semiconductor laser capable of switching light, and drives the semiconductor laser for switching based on print data information of a serial signal. Thus, the laser beam emitted from the semiconductor laser that is modulated by this switching drive is
In the rotary mirror driving unit 14 composed of a polygon mirror, the polygon mirror is driven to rotate corresponding to the printing operation, reflected on the surface of the photosensitive drum, and sub-scanned.
The surface of the photosensitive drum is exposed to form an electrostatic latent image. The laser beam that is sub-scanned on the surface of the photosensitive drum is a synchronization signal forming unit 1 including a BD photo sensor.
5, the sync signal, which is detected by the BD photosensor, amplified to a desired level, and compared with the reference pulse, becomes the sync signal forming section 15 at which the electrostatic latent image formation start position is formed in the main scanning direction. It is formed. This synchronization signal is given to the above-mentioned data conversion unit 12 and used in parallel-serial conversion of the print data information of the parallel signal into the print data information of the serial signal in the data conversion unit 12, and is used for print synchronization. In this way, the latent image forming process of the electrophotographic process is executed in the optical unit 11.

On the other hand, from the central control board 10, print density information, for example, print page information such as light and shade of data to be printed, color, photograph or newspaper is supplied to the developing unit 16. In the developing unit 16, print density information, temperature / humidity information related to the development process operating environment such as temperature / humidity from a temperature / humidity sensor (not shown), and a toner density sensor are used to detect the toner density in the developing unit and detect the toner density. A toner replenishment command is output when necessary from the toner concentration control unit 18 based on the toner concentration information from the toner concentration detection unit 17 that generates the concentration information. Based on the output toner replenishment command, the replenishment toner amount control unit 19
Controls the amount of toner to be replenished to a developing device (not shown) that contains the developer from the mixture of the toner that is the colorant and the carrier that conveys the toner to the surface of the photosensitive drum.

Incidentally, in the developing unit 16, for example, a digital switch, a rotary switch, an encoder switch, and the like are provided with toner density correction amount information relating to, for example, variations in agitating property in the developing device and variations in toner replenishment amount due to the peculiarities of the developing unit 16. A toner density correction amount information storage unit 20 configured by and configured to be manually stored is provided. Toner concentration correction amount information is read from the toner concentration correction amount information storage unit 20 according to an instruction from an operator or the central control board 10 when the apparatus is in operation.
The read toner concentration correction amount information is given to the toner concentration control unit 18, and a toner replenishment command is output so as to correct the concentration information from the toner concentration control unit 18 to stabilize the print quality.

In the present embodiment, the toner density correction amount information storage unit 20 is composed of a digital switch or the like, but it may be composed of a writable memory to write the toner density correction amount. The optical unit 11 and the developing unit 16 are arranged in the space occupied by the units by arranging the data conversion unit 12 or the toner concentration control unit 18 in consideration of the arrangement space of the elements constituting the optical unit 11 and the developing unit 16. The central control board 10 does not have a large influence, and the constituent elements of the central control board 10 are reduced, so that the overall size of the apparatus can be reduced.

The central control unit 1 in the present invention is the central control board 10 in the embodiment, the optical unit 2 is the optical unit 11, the data conversion unit 3 is the data conversion unit 12, the developing unit 4 is the developing unit 16, and the toner is the toner. The density correction amount information storage unit 5 corresponds to the toner density correction amount information storage unit 20, and the toner concentration control unit 6 corresponds to the toner concentration control unit 18.

[0014]

As described above, according to the first aspect of the present invention, by providing the data conversion portion on the optical unit side, it is possible to cope with the speeding up of printing and the resolution increase accompanied by the high frequency of the print data information. be able to. In addition, even if the length of the transmission path between the central control board and the optical unit is extended due to restrictions on the board layout when attempting to downsize the printing apparatus, the transmission path is provided by providing the data conversion unit on the optical unit side. It is also possible to prevent the extension of the length, and it is possible to prevent the data level from being lowered due to the extension of the transmission path length, the signal level of the print data information, the waveform rounding, and the noise.

Further, according to the second aspect of the present invention, the toner density control section and the toner density correction amount information storage section are provided on the developing unit side, so that the developing unit has its own characteristic such as agitation. High-quality printing can be obtained because the correction can be performed on the developing unit side.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an inventive principle of the present invention.

FIG. 2 is a block diagram for explaining a specific example in which an optical unit of a printing apparatus and a developing unit of the printing apparatus according to the present invention are applied to an electrophotographic apparatus.

FIG. 3 is a block diagram illustrating a conventional example.

[Explanation of symbols]

 1 Central control unit 10,30 Central control board 2,11,32 Optical unit 3,12,31 Data conversion unit 4,16,37 Development unit 5,20 Toner density correction amount information storage unit 6,18,36 Toner density control Part 13, 33 Laser drive part 14, 34 Rotating mirror drive part 15, 35 Synchronous signal forming part 17, 39 Toner density detection part 19, 38 Replenishment toner amount control part

Claims (2)

[Claims] 1. The optical unit (2) comprises a data converter (3) for converting print data information of a parallel signal from the central controller (1) into print data information of a serial signal, the data converter. An optical unit of a printing apparatus, which drives a laser beam based on print data information of a serial signal from (3). 2. The developing unit (4) includes a toner concentration correction amount information storage unit (5) for storing toner concentration correction amount information unique to the development unit (4), and a toner concentration correction amount information storage unit (5). 5) and a toner density control unit (6) for controlling the toner density based on the toner density correction amount information from the central control unit (1) and the toner density control unit (6). A developing unit of a printing apparatus, which controls density.