TONER DENSITY DETECTION APPARATUS AND IMAGE FORMING APPARATUS HAVING THE SAME

Abstract

A toner density detection apparatus has a sensor unit and a controller. The sensor unit irradiates a toner patch formed on an image carrier with light, splits the light reflected by the toner patch into first and second light components, receives the first and second light components, and outputs first and second light reception signals. The controller causes an analog/digital converter to convert, based on a reference voltage, the output first and second light reception signals into first and second digital data, and detects the density of the toner patch based on the first and second digital data. The toner density detection apparatus adjusts the toner density detection value based on a comparison between a first reference value stored in advance and the first digital data, and a comparison between a second reference value stored in advance and the second digital data.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a view of a toner density detection apparatus.

FIG. 2 is a block diagram of a controller of the toner density detection apparatus shown in FIG. 1.

FIG. 3 is a conceptual graph of an example output signal from a patch sensor unit of the toner density detection apparatus shown in FIG. 1.

FIG. 4 is a flowchart for explaining the operation of the controller of the toner density detection apparatus shown in FIG. 1.

FIG. 5 is a flowchart for explaining another operation of the controller of the toner density detection apparatus shown in FIG. 1.

FIG. 6 is a view of a conventional toner density detection apparatus.

FIG. 7 is a circuit diagram of a receiving unit of the conventional toner density detection apparatus shown in FIG. 6.

FIG. 8 is a sectional view of an image forming unit of an image forming apparatus according to the present invention.

Claims

1. A toner density detection apparatus comprising: a sensor unit configured to irradiate a pattern image for density measurement formed on an image carrier with light, split the light reflected by the pattern image into a first light component and a second light component, receive the first light component and the second light component, and output a first light reception signal and a second light reception signal;an analog/digital converter configured to convert, based on a reference voltage, the first light reception signal and second light reception signal output from the sensor unit into first digital data and second digital data;a density detection unit configured to detect a density of the pattern image based on the first digital data and the second digital data; andan adjusting unit configured to adjust the toner density detection value detected by the density detection unit, based on a comparison between a first reference value stored in correspondence with the density of the pattern image in advance and the first digital data, and a comparison between a second reference value stored in correspondence with the density of the pattern image in advance and the second digital data.

2. The apparatus according to claim 1, wherein the adjusting unit adjusts the reference voltage of the analog/digital converter based on the comparison results.

3. The apparatus according to claim 1, wherein the adjusting unit stores a difference value between a first reference value stored in correspondence with the density of the pattern image in advance and the first digital data, and a difference value between a second reference value stored in correspondence with the density of the pattern image in advance and the second digital data, and adjusts the first digital data and the second digital data, based on the difference values.

4. The apparatus according to claim 1, wherein the sensor unit includes: a light irradiation unit operable to irradiate the pattern image formed on the image carrier with light;a light splitting unit configured to split the light reflected by the pattern image into the first light component and the second light component;a first receiving unit configured to receive the first light component from the light splitting unit and detect a light amount of the first light component;a second receiving unit configured to receive the second light component from the light splitting unit and detect a light amount of the second light component;a first amplifier configured to amplify the signal from the first receiving unit and output the first light reception signal; anda second amplifier configured to amplify the signal from the second receiving unit and output the second light reception signal.

5. The apparatus according to claim 4, wherein the first receiving unit and the second receiving unit include a gain adjusting unit configured to adjust a gain in light amount detection.

6. An image forming apparatus comprising a toner density detection apparatus configured to detect a density of a pattern image for density measurement formed on an image carrier and to execute density control based on a density level of image data to form the pattern image and a density of the detected pattern image, the toner density detection apparatus including: a sensor unit configured to irradiate the pattern image formed on the image carrier with light, split the light reflected by the pattern image into a first light component and a second light component, receive the first light component and the second light component, and output a first light reception signal and a second light reception signal;an analog/digital converter configured to convert, based on a reference voltage, the first light reception signal and second light reception signal output from the sensor unit into first digital data and second digital data;a density detection unit configured to detect the density of the pattern image based on the first digital data and the second digital data; andan adjusting unit configured to adjust the toner density detection value detected by the density detection unit, based on a comparison between a first reference value stored in correspondence with the density of the pattern image in advance and the first digital data, and a comparison between a second reference value stored in correspondence with the density of the pattern image in advance and the second digital data.