Using a model with image

I have a model that has a type of image field. But while trying to save the model image is not sent and when I try to send via form submit is also not sent. Follows the code:

ps: I use rest

FORM

Code:

 xtype: 'form',            
            //padding: '10 10 10 10',
            //style: 'background-color: #fff;',
            fieldDefaults: {
                anchor: '100%',
                labelAlign: 'left',
                allowBlank: false,
                combineErrors: true,
                msgTarget: 'side',
                padding: 10
            },
            items: [
                {
                    xtype: 'textfield',
                    name: 'id',
                    fieldLabel: 'id',
                    hidden: true
                },
                {
                    layout: 'hbox',
                    items: [
                        {
                            xtype: 'textfield',
                            name: 'titulo',
                            fieldLabel: 'Titulo'
                        },
                        {
                            xtype: 'textfield',
                            name: 'fonte',
                            allowBlank: true,
                            fieldLabel: 'Fonte'
                        }
                    ]
                },
                {
                    xtype: 'htmleditor',
                    name: 'conteudo',
                    fieldLabel: 'Conteúdo',
                    enableFont: false,
                    enableAlignments: false,
                    enableFontSize: false
                },
                {
                    xtype: 'filefield',
                    emptyText: 'Selecione uma imagem',
                    fieldLabel: 'Imagem',
                    name: 'imagem',
                    buttonConfig: {
                        text: '',
                        iconCls: 'upload-icon'
                    }
                }
            ],

SAVE BUTTON ACTION

Code:

 var win = button.up('window'),
                form = win.down('form'),
                record = form.getRecord(),
                values = form.getValues();


        var novo = false;


        if (values.id > 0) {
            record.set(values);
        } else {
            record = Ext.create('ezCms.model.Noticia');
            record.set(values);
            Ext.getStore('noticias').add(record);
            novo = true;
        }


        win.close();
        Ext.getStore('noticias').sync();


        if (novo) { //faz reload para atualziar
            Ext.getStore('noticias').load();
        }

Using a model with image