A print head for writing data onto a photoreceptor, including a light source panel of light emitting elements arranged in a matrix, optical systems arranged in a matching matrix, light receiving elements, and a corrector. The optical systems each include at least a light-source-side lens and an image-side lens, and focus light from the light emitting elements onto different regions of the photoreceptor. The light receiving elements each include a light receiving surface disposed in a leaked light region and detect light incident on the light receiving surface. The leaked light region is in a gap between the light-source-side lens and the image-side lens of each of the optical systems occupied by optical paths of light transmitted through the light-source-side lenses but not incident on the image-side lenses. The corrector corrects amounts of light to be emitted from the light emitting elements based on the light detected.

An image forming apparatus includes: an LED print head exposing a photosensitive drum with light; a door arranged on one end side of the LED print head; a support portion for the LED print head operating in conjunction with opening and closing movements of the door, positioning the LED print head at a first position for exposing the photosensitive drum when the door is closed, and positioning the LED print head at a second position more apart from the photosensitive drum than the first position when the door is open; and a guide portion formed on the door and guiding a cleaning member to the LED print head, the guide portion having a first inclined surface which is lowered toward the LED print head so that the cleaning member is continuously held in contact with the LED print head under a state in which the door is open.

A print head includes a memory, an input and output unit, and a plurality of light emitting elements. The memory is configured to store a first light quantity value obtained by measuring a light quantity of each of the plurality of light emitting elements when supplied with a first reference current value, and a light quantity difference value between the first light quantity value and a second light quantity value obtained by measuring a light quantity of each of the plurality of light emitting elements when supplied with a second reference current value. The input and output unit is configured to output the first light quantity value and the light quantity difference value and receive a correction value determined based on the first light quantity value and the light quantity difference value. The light emitting elements are configured to emit light based on a correction current value corresponding to the correction value.

An image forming apparatus including a photoconductor and a light emitting unit further includes a generating unit configured to generate correction data used for correcting a shift in the sub-scanning direction of a latent image to be formed on the photoconductor; a correcting unit configured to correct image data based on the correction data; and a control unit configured to control light emission of the light emitting unit so as to form the latent image on the photoconductor. The generating unit is configured to generate the correction data based on configuration information of the light emitting unit, information indicating time required for causing a plurality of light emitting elements to emit light, and information indicating a rotation speed of the photoconductor.

In the image forming method, a halftone image is generated by performing halftone processing for an input image, a scanned image of a printed material on which on which the halftone image is printed is obtained, and a failure component of an image forming apparatus is identified based on a difference between the scanned image and the input image. In the generation, the halftone image is generated by representing a dot pattern of a halftone portion in a case where the input image is a test image for the failure diagnosis by a dot pattern whose frequency is relatively higher than that of a dot pattern that is applied to the halftone portion in a case where the input image is an image other than the test image.

In the image forming method, a halftone image is generated by performing halftone processing for an input image, a scanned image of a printed material on which on which the halftone image is printed is obtained, and a failure component of an image forming apparatus is identified based on a difference between the scanned image and the input image. In the generation, the halftone image is generated by representing a dot pattern of a halftone portion in a case where the input image is a test image for the failure diagnosis by a dot pattern whose frequency is relatively higher than that of a dot pattern that is applied to the halftone portion in a case where the input image is an image other than the test image.

An exposing device according to an embodiment includes: a light emitter; a first light blocking member including first apertures; a first lens array including first lenses, wherein each of the first lenses converges the light passing through the corresponding first aperture; a second light blocking member including second apertures; and a second lens array including second lenses, wherein each of the second lenses converges the light passing through the corresponding second aperture. An optical axis of each of the first lenses and an optical axis of the corresponding one of the second lenses substantially coincide with each other. A first aperture center of each of the first apertures and a second aperture center of the corresponding second aperture are disposed at a predetermined distance from the optical axis of the corresponding first lens and the optical axis of the corresponding second lens in an array direction of the light emitter.

An illuminating device according to an embodiment included in an image reading apparatus and an image forming apparatus includes light source portions, light-guiding members for illuminating an illumination target from an elongated light emitting face that extends in a longitudinal direction, by guiding light from the light source portions, and holding members for holding the light-guiding members. The holding members include holding portions for removably holding the light-guiding members, and tilted portions that reflect light emitted from the light emitting face, the tilted portions extending from a front end on the light emitting face side of the holding portions, obliquely widening with increasing distance from the light-guiding members.

A controller which causes a light emitting element to continuously perform minute emission for a plurality of dots in a level in which toner is not attached to a non-image section on an image bearing member is provided. The controller controls a first driving current for an image section and controls a second driving current used to perform the minute emission by the light emitting element in the non-image section several times in one job. In the image section, a driving current obtained by adding the first driving current to the second driving current is supplied so that the light emitting element emits light.

An illuminating device according to an embodiment included in an image reading apparatus and an image forming apparatus includes light source portions, light-guiding members for illuminating an illumination target from an elongated light emitting face that extends in a longitudinal direction, by guiding light from the light source portions, and holding members for holding the light-guiding members. The holding members include holding portions for removably holding the light-guiding members, and tilted portions that reflect light emitted from the light emitting face, the tilted portions extending from a front end on the light emitting face side of the holding portions, obliquely widening with increasing distance from the light-guiding members.